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This study focused on a jellyfish monitoring and sampling programme along the eastern Qatar seawaters and reports the first jellyfish records for the Qatar pelagic ecosystem and the occurrence of three scyphozoans: the semaeostome Chrysaora cf. caliparea and the rhizostomes Marivagia stellata and Catostylus perezi, considered as first records of Scyphomedusae for Qatar. Jellyfish monitoring, underwater photography and sample collection were carried out along an inshore-offshore transect composed of five stations along the eastern coast of Qatar. Jellyfish material examined, systematic description, general distribution and sting risk of the three species are provided. The discussion section highlights the blooming capabilities of Chrysaora cf. caliparea and Catostylus perezi, while Marivagia stellata seems scarcer, being spotted for the first time since we started our jellyfish investigation programme in August 2018.

In the framework of the Coral Management Plan for the North Field Expansion Project (NFE) and North Field Production Sustainability Project (NFPS), Qatargas has partnered with the Environmental Science Center (ESC) to develop the first land-based coral nursery in Qatar. This nursery plan includes the extraction of 1000 corals’ colonies from the NFPS and NFE pipeline corridors, north of Ras Laffan, and hence their transportation to the nursery facility, rehabilitation under controlled husbandry conditions, fragmentation, out-plantation to carefully selected recipient sites and long-term monitoring (up to 48 months). The first two batches of 200 corals were extracted in March and outplanted in April 2021. Results of the first two monitoring events, after 44 and 66 days, were quite encouraging for the seven coral genera tested. Attachment success was very high, with 92% to 97% of the outplanted fragments being detected during monitoring. No bleaching, disease or mortality was recorded so far. The coral propagation methods used in this project (i.e., fragmentation, husbandry and outplanting), although widely used, have been tested with a restricted number of branching coral species and usually in in-situ nurseries. Our project is among the first to apply this type of approach (land-based nursery) to reef restoration in the Arabian Gulf.

portuguesA avaliacao da qualidade da agua baseada em macroinvertebrados em ribeiras temporarias e uma questao importante, mas ainda pouco estudada. Investigar diferentes aspectos da ecologia de macroinvertebrados nestas ribeiras e, portanto, fundamental para a implementacao de programas de bio-avaliacao. No presente trabalho foi investigada a variabilidade nas metricas da comunidade de macroinvertebrados e indice de qualidade da agua entre diferentes tipos de habitat (blocos, cascalho, gravilha, areia, macrofitos, materia orgânica particulada ) e tipologias das ribeiras mediterrânicas temporarias (Rios do Sul de Media-Grande Dimensao, Rios Montanhosos do Sul, Rios do Sul de Pequena Dimensao, Calcarios do Algarve). A estrutura das comunidades bentonicas mostrou diferencas entre habitats e tipologias, mas nao houve interaccao entre estes dois factores, indicando que o efeito da tipologia nao depende dos habitats que estao presentes neste tipo de ribeira. De forma geral, a estrutura da comunidade foi semelhante entre substratos minerais e macrofitos, reflectindo um baixo numero de taxa com um valor indicador significativo, o que sugere a prevalencia de uma tatica generalista e baixa seletividade em termos de particao do habitat nestas ribeiras temporarias. Um maior numero de taxa com potencial indicador foi encontrado para diferentes tipologias de ribeira, fornecendo evidencias de que as tipologias sao melhores preditores para ocorrencias de especies do que uma unidade de habitat nesta escala. Alem disso, foram relatados efeitos significativos de Habitat e Tipologia para o indice de qualidade da agua. As diferencas foram particularmente entre cascalho e os habitats orgânicos ou de deposicao (macrofitos / areia / materia orgânica particulada). Para a tipologia foram observadas diferencas entre calcarias e nao calcarias. Devido as diferencas observadas no indice de qualidade da agua entre habitats orgânicos e nao orgânicos, a amostragem na escala de comprimento da ribeira deve incluir ambos os tipos de substrato. EnglishMacroinvertebrate-based water quality assessment in temporary streams is an important yet still understudied issue. Investigat-ing different aspects of macroinvertebrate distribution in these streams is therefore highly necessary for the successful imple-mentation of bio-assessment programs. We investigated the variability in macroinvertebrate communities (number of families, abundance, taxonomic richness) and water quality index among six different habitat types (boulder, cobble, gravel, sand, macrophytes, particulate organic matter) and four stream typologies (medium-large southern rivers; southern moun-tainous rivers; small southern rivers; calcareous rivers). Samples were collected at 32 intermittent and 4 permanent sites in Mediterranean-type streams.The structure of benthic communities showed differences among both habitats and typologies, but there was no interaction among these two factors, indicating that the effect of stream typology does not depend on the habitats that are present in the given stream type. Overall community structure was similar among mineral substrates and macrophytes, which was also reflected in low number of taxa with significant indicator values suggesting the prevalence of generalist tactic and low selectivity in terms of habitat partitioning at these temporary streams. Much higher number of indicator taxa was found for different stream typologies providing evidence that stream types are better predictor for taxa occurrences than a habitat unit at this scale. Southern mountain-ous streams hosted the highest number of families with significant Indicator Values suggesting that this typology is important for many families with less generalistic set of traits. This typology must be carefully addressed in monitoring programs for water quality assessment even at such fine scale. Further, we reported significant effects of Habitat and Typology for water quality index. Differences were particularly between gravel and organic or depositional habitats (macrophytes/sand/particulate organic matter). For the typology differences were observed between calcareous and non-calcareous stream types

Oil and gas platforms act as artificial habitats for a myriad of marine organisms. In this study, we used opportunistic remotely operated vehicle (ROV) data to describe fouling assemblages through the characterization of functional groups in the Al Shaheen oil field, situated in Qatari waters. The surveys showed a strong vertical stratification, with the number of functional groups increasing from the surface to the bottom. In addition, the majority of functional groups had their highest frequency of occurrence in the 35-60 m interval. In turn, multivariate analyses showed a slight structure among platforms with different ages. The lowest number of functional groups occurred in the early ages (2-3 years old), and some groups either increased or decreased their frequency and abundance along the years. A step further is now required to determine whether these platform foundations should be converted to reefs after their decommissioning (i.e., Rigs to Reefs approach).

The coral reef ecosystems of the Arabian/Persian Gulf (the Gulf) are facing profound pressure from climate change (extreme temperatures) and anthropogenic (land-use and population-related) stressors. Increasing degradation at local and regional scales has already resulted in widespread coral cover reduction. Connectivity, the transport and exchange of larvae among geographically separated populations, plays an essential role in recovery and maintenance of biodiversity and resilience of coral reef populations. Here, an oceanographic model in 3-D high-resolution was used to simulate particle dispersion of "virtual larvae." We investigated the potential physical connectivity of coral reefs among different regions in the Gulf. Simulations reveal that basin-scale circulation is responsible for broader spatial dispersion of the larvae in the central region of the Gulf, and tidally-driven currents characterized the more localized connectivity pattern in regions along the shores in the Gulf's southern part. Results suggest predominant self-recruitment of reefs with highest source and sink ratios along the Bahrain and western Qatar coasts, followed by the south eastern Qatar and continental Abu Dhabi coast. The central sector of the Gulf is suggested as recruitment source in a stepping-stone dynamics. Recruitment intensity declined moving away from the Straits of Hormuz. Connectivity varied in models assuming passive versus active mode of larvae movement. This suggests that larval behaviour needs to be taken into consideration when establishing dispersion models, and establishing conservation strategies for these vulnerable ecosystems.

Rising atmospheric CO2 alters the ocean biochemistry in the process known as ocean acidification (OA). It influences biodiversity at different levels, including zooplankton, which is a key component of aquatic communities and plays a pivotal role in the structure and functioning of marine planktonic food webs as a major link between pelagic primary producers and planktivorous. The effect of OA on the fitness of individual zooplanktonic species has been reported by many studies mostly developed under laboratory conditions. In this context, this chapter reviews the OA effects on zooplankton and describes the potential of natural shallow-water CO2 vents as in situ laboratories. The impact on zooplankton assemblages is shown from a study in the North Atlantic (Azores islands) and the suitability of this area for future studies on marine organisms and ecosystems. Sites with naturally elevated CO2 conditions are described, including which variables and limitations must be considered. Results shown are highly relevant to improve our predictions of the responses of zooplankton to climate change stressors including OA. Future studies including long-term multigenerational exposure to multiple stressors (e.g. increased pCO2 and food shortage) are a priority to understand the adaptation capacity of common species and how the zooplankton communities will shift.

Sites with naturally high CO

More recently, Qatar has undergone a remarkable social and economic transformation in less than a generation. Although Qataris have a historic connection to the sea, dating back to the pearl diving days in the 19th century, the marine environment requires many interventions to be managed in a sustainable manner. Given the fact that coral reefs play an important role in the coastal ecosystem in this peninsular state, principles of environment sustainability should be undertaken for this significant habitats along the Qatari shores. Local pressures and climate change are among the most important factors that have negatively affected Qatar's coral communities. Other major threats result largely from human activities. To achieve sustainable development that preserves the Environment is a core goal especially included in all recent development regimes in Qatar. A balance between development needs and protecting the environment represents the fourth pillar of Qatar National Vision 2030. An explicit reference is also documented in the two most recently adopted strategies of development. This study introduces a good opportunity for Qatar to position itself as a regional leader in the use of environmental management systems that integrate multiple partners in guiding and conserving coral reefs as part of valuable ecosystems as a right of future generations of Qatari nationals guaranteed by the country's sustainable development agenda. It defines 4-stage engagement framework that include 9 diverse stakeholders proposed to participate in the management of coral reef ecosystems, therefore, facilitate monitoring and enforcement, enhance understanding of system dynamics, improve management capacity to respond to shocks and disturbances, and facilitate teamwork. This publication was made possible by the NPRP award [NPRP8-952-1-186] from the Qatar National Research Fund (a member of The Qatar Foundation) through the National Priority Research Program.

The coastline of Qatar is a rich mosaic of productive and diverse ecosystems including mangrove forests, intertidal mudflats (sabkha), seagrass beds, and coral reefs. These ecologically interconnected ecosystems contain a substantial proportion of Qatar's total biodiversity, and support an estimated 97% of the >US$ 67 million in annual commercial fisheries, the highest value resource sector after petroleum. The extreme environmental conditions that characterize Qatar has led to fauna that are robust compared with other regions, but makes them highly sensitive to further pressure from anthropogenic stress. These vulnerable ecosystems have come under increasing pressure in recent decades as a result of dramatic expansion of coastal development, and threats to these ecosystems are likely to accelerate in the coming years as Qatar's economy and population continue to grow. Although environmental regulation had historically lagged behind the rapid pace of development, in recent years Qatar's leadership has aggressively expanded environmental management as a result of the growing awareness of the importance of coastal ecosystems. While these improvements are encouraging, management remains challenged by its current sectorial, project-driven focus. Ecosystem-based management (EBM) offers an opportunity to overcome these challenges by integrating impacts from across all major activities in multiple sectors and considering their cumulative effects on ecosystem services and products. While an EBM approach would require modest reprioritizing of existing processes and attention to addressing deficiencies in data needed to support decision making, it has the potential to greatly enhance the efficiency and effectiveness of coastal zone management. The article closes by summarizing a recently initiated research project on coral reefs and seagrass beds in Qatar which can serve as a model for development of the EBM approach for other coastal ecosystems in Qatar.

An assessment of vertical distribution, diel migration, taxonomic and functional diversity of fishes was carried out at offshore platforms in The (Arabian–Iranian–Persian) Gulf. Video footage was recorded at the Al Shaheen oil field between 2007 and 2014 using a remotely operated vehicle (ROV). A total of 12 822 individual fishes, from 83 taxonomic groups were recorded around the platforms. All the species identified are considered native to The Gulf, although Cyclichthys orbicularis and Lutjanus indicus were recorded for the first time in Qatari waters. Several trends were uncovered in the vertical distribution of the fish community; most species were observed between 20 and 50 m depth and fish abundance decreased towards the bottom, with the highest abundances recorded in the upper layers, i.e. down to 40 m depth. Vertical variation in fish diversity, however, was generally not accompanied by differences in vertical movements. Carnivores and invertivores were the dominant trophic groups, being found at each depth range from surface to seabed. The functional indices showed no significant differences between water depths or diel cycles. The study demonstrates that oil platforms represent a hotspot of fish diversity and interesting sites for studying fish communities, abundance and behaviour.

Current classifications used in bioassessment programs, as defined by the Water Framework Directive (WFD), do not sufficiently capture the variability present in temporary Mediterranean streams. This may result in inaccurate evaluation of the water quality biological metrics and difficulties in setting reference conditions. The aim of the study was to examine if aquatic invertebrate data of increased taxonomical resolution but expressed on a binary abundance (frequent/rare) scale and referring to good bioindicator species only suffice to indicate clear gradients in water courses with high natural variability such as intermittent Mediterranean streams. Invertebrate samples were collected from 74 sites in the Quarteira River basin, located in southern Portugal. Their classification with the use of a Kohonen artificial neural network (i.e., self-organising map, SOM) resulted in five categories. The variables that drove this categorization were primarily altitude, temperature and conductivity, but also type of substrate, riparian cover and percentage of riffles present. According to the indicator species analysis (ISA), almost all the studied taxa were significantly associated with certain SOM categories except for the category that included sites with disrupted flow regime. The SOM and ISA allowed us to effectively recognize biotic and abiotic patterns. Combined application of both methods may thus greatly enhance the effectiveness and precision of biological surveillance and establish reference sites for specific channel units in streams with high natural variability such as intermittent Mediterranean streams. The authors specially acknowledge Samantha Hughes, Simone Varandas and Maria Schrder for their help in taxonomic identification of macroinvertebrates and species selection, and Tom Goulding for his comments on the manuscript and English review. The following work was a part of the IMPACT project funded by Foundation for Science and Technology (FCT) of Portugal ( ERA-IWRM/0003/2009 ). Comments by two anonymous referees substantially improved the original manuscript. Scopus

19 páginas.- 5 figuras.- 2 tablas.- referencias.- Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10750-020-04263-5) contains supplementary material, which is available to authorized users., Anthropogenic impact can alter food web structure through changes in species interactions. In this study, we explored the food web of three Mediterranean stream reaches (two seasonal and one permanent) along an anthropogenic impact gradient to test the hypothesis that increasing impact simplifies food webs. To test this, we applied the isotopic (δ13C and δ15N) niche concept to compare reaches using isotopic metrics (isotopic richness, divergence, dispersion, evenness, and redundancy). The isotopic indices were useful to identify differences in food web architecture among the three reaches. The least impacted site had the highest isotopic richness, dispersion, and isotopic redundancy, suggesting higher ecological resilience at this site. The effect of disturbance in the remaining two sites was masked by the presence of invasive crayfish, which increased isotopic divergence and was responsible for higher food-chain length in the most impacted reach, but not in the moderately impacted reach. Consumers displayed generalistic feeding habits, with Bayesian mixing models indicating that they relied primarily on a mixture of periphyton, other macroinvertebrates, and to a lesser extent, detritus. Some taxa displayed changes in their dietary habitats depending on the site, indicating that the same type of taxa fed on distinct foods at each stream reach., The following work was a part of the IMPACT project funded by Foundation for Science and Technology (FCT) of Portugal (ERA558IWRM/0003/2009)

The coral reef ecosystems of the Arabian/Persian Gulf (the Gulf) are facing profound pressure from climate change (extreme temperatures) and anthropogenic (land-use and population-related) stressors. Increasing degradation at local and regional scales has already resulted in widespread coral cover reduction. Connectivity, the transport and exchange of larvae among geographically separated populations, plays an essential role in recovery and maintenance of biodiversity and resilience of coral reef populations. Here, an oceanographic model in 3-D high-resolution was used to simulate particle dispersion of “virtual larvae.” We investigated the potential physical connectivity of coral reefs among different regions in the Gulf. Simulations reveal that basin-scale circulation is responsible for broader spatial dispersion of the larvae in the central region of the Gulf, and tidally-driven currents characterized the more localized connectivity pattern in regions along the shores in the Gulf's southern part. Results suggest predominant self-recruitment of reefs with highest source and sink ratios along the Bahrain and western Qatar coasts, followed by the south eastern Qatar and continental Abu Dhabi coast. The central sector of the Gulf is suggested as recruitment source in a stepping-stone dynamics. Recruitment intensity declined moving away from the Straits of Hormuz. Connectivity varied in models assuming passive versus active mode of larvae movement. This suggests that larval behaviour needs to be taken into consideration when establishing dispersion models, and establishing conservation strategies for these vulnerable ecosystems.

Coral reefs are facing global challenges, with climate change causing recurrent coral bleaching events at a faster rate than corals may be able to recover from, and leading to an overall decline of coral cover and shifts in communities across the tropics. Scleractinian corals are ecosystem builders that provide a habitat for numerous marine species, and their loss is disrupting a range of ecosystem functions and services that reefs normally provide. Climate change will continue to warm the world’s oceans, leading to thermal conditions similar to those already existing in the Persian/Arabian Gulf (hereafter termed “the Gulf”). Indeed, the Gulf is in the summer the world’s hottest sea (SST > 36 °C) and thus represents a “natural laboratory” in which to understand how reefs in other regions might respond under increasing temperatures. Recent research has shown that physiological thresholds of Persian/Arabian Gulf corals are higher than elsewhere, allowing them to survive in the Gulf’s extreme temperatures. However, these marginal conditions result in coral communities that are low in diversity and comprised mainly of stress-tolerant species that provide limited three-dimensional structure. This low complexity habitat and the environmental extremes are associated with reef fish communities that have lower diversity, abundance, biomass, and size at maturity compared with conspecifics outside of the Gulf, and these fish communities have been shown to function quite differently. As climate change continues, coral reef ecosystems around the world are expected to gradually shift to thermal conditions similar to the present-day Gulf, and as such today’s Gulf can provide insights into ecological patterns and processes we can expect in the tropics in the future. However, while Gulf fauna are adapted to extreme temperatures, they live very near their upper thermal threshold each summer. Recent climate change has resulted in recurrent mass bleaching events that have caused widespread loss of coral and knock-on effects on reef-dependent fishes. Thus, paradoxically, on the world’s most robust reefs, we may be witnessing the world’s first region-wide extirpation of reef fauna as a result of climate change.

Conservation and management of marine biodiversity depends on biomonitoring of marine habitats, but current approaches are resource‐intensive and require different approaches for different organisms. Environmental DNA (eDNA) extracted from water samples is an efficient and versatile approach to detecting aquatic animals. In the ocean, eDNA composition reflects local fauna at fine spatial scales, but little is known about the effectiveness of eDNA‐based monitoring of marine communities at larger scales. We investigated the potential of eDNA to characterize and distinguish marine communities at large spatial scales by comparing vertebrate species composition among marine habitats in Qatar, the Arabian Gulf (also known as the Persian Gulf), based on eDNA metabarcoding of seawater samples. We conducted species accumulation analyses to estimate how much of the vertebrate diversity we detected. We obtained eDNA sequences from a diverse assemblage of marine vertebrates, spanning 191 taxa in 73 families. These included rare and endangered species and covered 36% of the bony fish genera previously recorded in the Gulf. Sites of similar habitat type were also similar in eDNA composition. The species accumulation analyses showed that the number of sample replicates was insufficient for some sampling sites but suggested that a few hundred eDNA samples could potentially capture >90% of the marine vertebrate diversity in the study area. Our results confirm that seawater samples contain habitat‐characteristic molecular signatures and that eDNA monitoring can efficiently cover vertebrate diversity at scales relevant to national and regional conservation and management., Article impact statement: Environmental DNA provides habitat‐characteristic molecular signatures and can be used efficiently to map marine biodiversity at large spatial scales.

© 2020 Elsevier B.V. A novel approach of combining manipulative field experiments and cytogenetic endpoints was used to assess the genotoxic impact of chemical contamination on a local model bivalve species, the pearl oyster -Pinctada imbricata radiata. Baseline levels of Polycyclic Aromatic Hydrocarbons (PAHs), Total Petroleum Hydrocarbons (TPHs) and trace metals were determined from surface sediments and pearl oyster tissue collected from 3 coastal locations in Qatar (Umm Bab, Dukhan and Al-Wakra). Initial aneuploidy –numerical chromosomal abnormality-level in oysters was also assessed during the baseline survey. The oysters’ ability to adapt to new sites, with distinct signatures in terms of chemical contamination, was assessed using a reciprocal transplantation experiment among the same 3 coastal locations, from February to April 2016. Significant differences in sediment contamination levels were detected among the 3 sites. TPHs were in higher concentrations at Umm Bab (western coast), while higher concentrations of metals and PAHs were found at Dukhan (western coast) and Al-Wakra (eastern coast), respectively. Oysters transplanted between locations showed lower levels of aneuploidy, relative to those kept in the original location (controls). Transplanted oysters, regardless of the contamination levels at the origin and destination, showed recovery from initial aneuploidy levels. Moreover, there was a larger percentage of aneuploid cells with chromosomal gain than with chromosomal loss in all treatments, which contrasts with the pattern usually observed in bivalves. This work was supported by Qatar University [grant QUSTCAS-FALL-15/16-32]. The authors are thankful to the QU-DBES staff: Mariam Safi, DM Estremadura, Khwaja Abdul Matheen, Abdol Ali Moghaddasi and Muhammad Habeeb. Also thanks to the QU-ESC staff: Noora Al Shamary, Hassan Hassan, Mazen Assali, Sara Al Saadi, Mariem Bastaki and Hamood Al Saadi. The authors are also grateful to Ismail Al-Shaik and Linso Varghese from Exxon Mobil for helping with the inorganic analysis and to Dr. Elizabeth Goergen, for proofreading the manuscript.

Baseline assessment of fish communities and selected environmental variables (salinity, water temperature, water transparency, current speed, total suspended solid, chlorophyll a) was conducted in Pampanga estuary (Philippines) during a specific dry season (April 2010). The aims were: (a) to examine the variations of fish diversity and community structure, in relation to neap and spring tides and estuary zones and; (b) to examine the influence of environmental variables on fish communities. Reconnaissance showed that salinity was measurable at 6.8 kilometers from the rivermouth, for the surface and mid-water layers, and at 15.9 kilometers for the bottom layers, indicating the occurrence of a salt wedge. Bottom salinity was used to establish the sampling stations, grouped into 3 zones (lower 1-3, middle 4-6, upper 7-9). Sampling of fish, using otter trawl, and measurement of environmental variables were done under four tidal conditions at each station (neap low and high tide; spring low and high tide). Neap tide showed low and homogenous horizontal salinity, higher temperature, slower current speed, high TSS and chlorophyll a, whereas, spring tide showed higher salinity, horizontal saline stratification, lower temperature, faster current speed, low TSS and chlorophyll a. A total of 330 fish were captured from 32 trawl samples, encompassing 20 families and 27 species. Number of species generally did not vary between neap (20) and spring tide (18), but showed a decreasing pattern from lower to the upper estuary. Only 36% of total species were shared between neap and spring tides. Fish abundance was significantly affected by neap and spring tide, and zonation, whereas fish biomass was solely affected by zonation. Arius manillensis was the most typifying species, suggesting high probability of encounter. Chlorophyll a, TSS, salinity and current speed have a significant influence on the variations of abundance, biomass and frequency of occurrence of particular fish species. (C) 2020 Elsevier B.V. All rights reserved. info:eu-repo/semantics/publishedVersion

Arabian Gulf coral communities are particularly known for their utmost tolerance and adaptation to region’s extreme environmental conditions. However, stress through increasing sea temperatures, salinities, sustained coastal development, etc., has resulted in shifts in reef communities across the region in recent years. We conducted a comprehensive assessment of the status of coral communities at 15 reef sites, NW Arabian Gulf, focusing on the abundance of living coral cover and species biodiversity using photoquadrat surveys; we also investigate potential spatial and environmental drivers of changes in coral communities. We show a strong north-to-south gradient of declining live coral cover (38% to 13%) and species richness (28 to 7 species), with an additional reduction of species richness in coastal areas (2 species). Recent surveys in late summer 2017 revealed 100% bleaching in inshore coral communities and occasionally, the complete loss of coral cover resulting in a shift to a non-coral ecosystem composed of mostly rubble and turf-algae. Species turnover (Beta-diversity) and canonical correspondence analyses determined that environmental factors such as depth, salinity and sea surface temperatures play a significant role in driving these spatial patterns of coral biodiversity and biogeography and in predicting their shift as function of future regional climate scenarios.

In this study we assessed the small-scale effects of submarine groundwater discharges (SGD) on macrofaunal assemblages associated with shallow sandy sediments along the south coast of Portugal. Corer samples were collected in a (1) subtidal seep, (2) at the edge of the seep (periphery) and (3) in the surrounding area. Community structure varied across areas, with diversity, species richness and evenness generally low at seep relatively to the surrounding area. Community composition within the seep was reduced to a small number of taxa, although total abundance was similar between seeps and surrounding areas. The seep was characterized by a distinct hydrological environment, with lower salinity and pH, relative to the surroundings sandy areas. More than 93% of the benthic macrofauna in the seep was dominated by Lumbricillus lineatus (enchytraeid oligochaetes). This study is the first to record the presence of this euryaline species in Portuguese marine waters. In the surrounding area Spionidae Polychaetes and Bathyporeia sp. (Amphipoda) were the most frequent and abundant taxa. These findings provide evidence for a direct association between SGD effect and the composition of benthic marine assemblages. The patchy habitat created by groundwater seep allowed euryhaline species with short and fast recruitment times to occur in a fully marine environment. Whether this pattern is consistent, or only occurs when smooth favorable sea conditions are not superimposed on the groundwater effect remains uncertain.

Artificial structures get introduced into the marine environment by accident (e.g., shipwrecks) or intentionally, for logistical (i.e., coastal protection), industrial (i.e., oil exploitation) or biological habitat enhancement (i.e., artificial reefs). Similarly to other types of man-made submerged structures, offshore oil and gas platforms provide adequate hard substratum for the development of sessile marine invertebrates and to increase habitat and food availability for fishes and other motile marine organisms (Svane and Petersen, 2001). Furthermore, offshore platforms generally face minimum external interference and are usually located in waters with strong currents, which facilitate larval dispersal and settlement. Despite the fact that there are currently more than 800 offshore oil and gas platforms in the Arabian Gulf (Sheppard et al., 2012), scarce information exists about the biological assemblages associated to these structures (Burt et al., 2012; Stachowitsch et al., 2002). In fact, oil and gas platforms are high-security areas with an exclusion zone of at least 500 m around the structures (Kashubsky and Morrison, 2013), which prevents fishing and other human impacts, but also restricts sampling for scientific purposes. Considering the substantial habitat and diversity losses of natural reefs in recent years, the perceived ecological role of these offshore structures is gaining increasing recognition. Several research and industrial programs have tried to promote the transition of decommissioned platforms into artificial reefs (e.g., Rigs to Reefs, Reggio Jr, 1987). It is vital, therefore, to study the community structure in such isolated marine habitats, to assess their structural and functional similarity and connectivity to natural marine ecosystems (Zintzen et al., 2008), in order to provide the scientific underpinning to the planning and decommissioning stage of the platforms. These issues are currently being addressed in the framework of the project “Connectivity, diversity and genetic flow between offshore natural coral reefs and oil platforms - NPRP No.: 7-1129-1-201”. In this specific study we aim to understand the recruitment and succession patterns of fouling communities offshore in Qatari waters, using stainless steel plates as artificial substrates, in order to mimic the stainless steel jackets, which generally support offshore oil platform in the Gulf. In October 2016, six vertical structures were deployed in the northeast of the Qatari Exclusive Economic Zone, in an area between the Al Shaheen oil field and natural offshore reefs, to investigate the source of the epibenthic species that colonize these artificial substrates. Each structure supports 30 stainless steel fouling plates (20 × 20 cm), spaced by 1 m, at depths ranging between 10 m and 45 m. Temperature data loggers (Onset TidbiT) were attached to the plate structures, at max and min depth, to investigate how the temperature and depth variations affect recruitment and development of fouling assemblages. All the structures were successfully retrieved during the first assessment, done 15 weeks after deployment, in February 2017. After all the plates were photographed and data downloaded from the temperature loggers, the structures were re-deployed in the same location. This imagery is currently being analyzed using the online platform CoralNet, to assess the percentage cover, abundance and diversity of the fouling assemblages. Preliminary results of this first assessment indicate strong invertebrate recruitment, with almost 100% cover of the plates, at all depths and locations. A clear vertical gradient was, however, apparent, with diversity and cover generally increasing with depth. Barnacles, bivalves, anemones and fenestrate bryozoans were dominant at shallow depths, while other types of macroinvertebrates, such as encrusting sponges, foliaceous bryozoans and hydrozoans, became more dominant as depth increased. As expected, important seasonal variations of seawater temperature (e.g summer-winter) were registered in shallow (< 10 m) and deep (> 40 m) layers. Variations observed in deep water (>40 m) during autumn and early winter were, however, larger than expected. High variability was found in all locations, with sea temperatures ranging 3-4°C during one single day. The semi-diurnal and lunar periodicity of these variations strongly suggests they are associated with tidal cycles. The full seasonal time series (one year), which will be available in November 2017, will allow the precise delimitation of the periodicity and magnitude of these temperature variations. The final data analyses will integrate data on temperature with depth and distance among structures to infer on recruitment and succession of sessile and mobile epifauna. References Burt, J.A., Bartholomew, A., Feary, D.A., 2012. Man-Made Structures as Artificial Reefs in the Gulf, in: Riegl, B.M., Purkis, S.J. (Eds.), Coral Reefs of the Gulf, Coral Reefs of the World. Springer Netherlands, pp. 171–186.Kashubsky, M., Morrison, A., 2013. Security of offshore oil and gas facilities: exclusion zones and ships’ routeing. Aust. J. Marit. Ocean Aff. 5, 1–10. doi:10.1080/18366503.2013.10815725Reggio Jr, V.C., 1987. Rigs-to-reefs. Fisheries 12, 2–7.Sheppard, C., Al-Husiani, M., Al-Jamali, F., Al-Yamani, F., Baldwin, R., Bishop, J., Benzoni, F., Dutrieux, E., Dulvy, N.K., Durvasula, S.R.V., Jones, D.A., Loughland, R., Medio, D., Nithyanandan, M., Pilling, G.M., Polikarpov, I., Price, A.R.G., Purkis, S.J., Riegl, B.M., Saburova, M., Samimi-Namin, K., Taylor, O., Wilson, S., Zainal, K., 2012. Environmental Concerns for the Future of Gulf Coral Reefs, in: Riegl, B.M., Purkis, S.J. (Eds.), Coral Reefs of the Gulf, Coral Reefs of the World. Springer Netherlands, pp. 349–373.Stachowitsch, M., Kikinger, R., Herler, J., Zolda, P., Geutebrück, E., 2002. Offshore oil platforms and fouling communities in the southern Arabian Gulf (Abu Dhabi). Mar. Pollut. Bull. 44, 853–860. doi:10.1016/S0025-326X(02)00085-1Svane, I., Petersen, J.K., 2001. On the Problems of Epibioses, Fouling and Artificial Reefs, a Review. Mar. Ecol. 22, 169–188. doi:10.1046/j.1439-0485.2001.01729.xZintzen, V., Norro, A., Massin, C., Mallefet, J., 2008. Spatial variability of epifaunal communities from artificial habitat: Shipwrecks in the Southern Bight of the North Sea. Estuar. Coast. Shelf Sci. 76, 327–344. doi:10.1016/j.ecss.2007.07.012

About one third of the oil and gas extracted worldwide comes from offshore sources. There is currently thousands of large-scale oil and gas platforms spread across the seas and coastal oceans, from the North Sea to the seas of South Asia. Although their primary purpose is not related to enrichment of biodiversity, gas and oil platforms can act as large and complex artificial marine habitats for a wide range of marine organisms, including sessile invertebrates and fishes. These structures have shown to enhance ecosystem function, especially secondary fish production, relative to adjacent natural reefs, besides being among the most productive marine fish habitats globally. Indeed oil platforms constitute important fish aggregating devices, especially in areas subjected to a range of environmental perturbations. Hard substratum availability combined with exclusion zones around these structures allows for the development of diverse fish assemblages. We carried out the first assessment of vertical distribution, diel migration, taxonomic and functional diversity of fishes at offshore platforms in the Arabian Gulf. Video footages were recorded at the Al Shaheen Oil Field, between 2007 and 2014 using a Remotely Operated Vehicle (ROV). Indeed diving and snorkeling are strictly forbidden in the exclusion zone around offshore platforms, precluding conventional monitoring techniques such as underwater visual census, collection of sessile organisms, etc. Routine inspection and maintenance surveys, however, are conducted to monitor the state of underwater structures using ROVs. A total of 4,510 video files, containing 120 hours of underwater video recordings, were provided by Maersk Oil Qatar A/S. These videos were recorded over six years (2007, 2009, 2010, 2011, 2012 and 2014), during day and night, at the 9 platform locations (A-I) within the Al Shaheen Oil Field using a ROV of the model SAAB Seaeye Surveyor Plus 229. To assess the local fish community, a total of 242 videos amounting to twenty-one hours of observation were selected randomly, however, if no fish appear in a selected video a new video was randomly selected from the list. This work represents the first assessment of reef fish communities inhabiting oil and gas platforms in the Arabian Gulf. A total of 12,822 fish, belonging to 83 taxonomic groups were recorded around the platforms. Among them, two species are first recorded for Qatari waters: Cyclichthys orbicularis and Lutjanus indicus. In addition two chondrichthyes, one endangered (Stegostoma fasciatum) and a vulnerable species (Taeniurops meyeni), were also observed across the platforms. Several trends were found in the vertical distribution of the fish community, most species were observed between 20 and 50 m depth and higher fish abundance recorded in the upper layers, down to 40 m depth and decreasing with depth. Vertical variation, however, in fish diversity was generally not accompanied by differences in vertical movements. The vertical variation, however, in fish diversity was not accompanied by differences in vertical movements of the fish. These results suggest that the vertical zonation pattern does not change, or only changes slightly, on a daily basis. The mean centers of mass of the most abundant fish species did not overlap, likely due to potential competition or niche differences. The dominant trophic groups were carnivores and invertivores, being well represented at each depth range (each spanning 10 m) from surface to seabed. Diel vertical movement was observed only for Acanthopagrus bifasciatus, which was concentrated at shallow depths during the daytime but migrated to deeper layers at night. The functional indices showed no significant differences between water depths or diel cycles (day / night). Besides the temperature variation, the reduced light penetration due to platform structures makes difficult the algal growth necessary for browsing herbivorous fish. Thereby, the effect of sunlight penetration may be reflected in the vertical distribution of herbivorous fish, which are rare in deeper layers. Planktivores are densely grouped within and just below the thermocline, which is located around 18 m during summertime. The study demonstrates that oil platforms represent a hotspot of fish diversity and interesting sites for studying fish communities, abundance and behaviour.

The geographical and hydrological characteristics and industrial activities of the Arabian/Persian Gulf contribute to its classification as a stressed marine environment. The persistency of some contaminants released by human activity is putting additional pressure on this already fragile system. Several studies have assessed the chemical contamination levels in Qatari coastal sediments but this is one of a few studies that assessed their eco-genotoxicological impacts, by using cytogenetic endpoints in a local model bivalve species. Bivalves were specifically selected for this study due to their role as filter feeders, high tolerance for harsh environmental conditions, and availability around Qatar. In this project, determination of Polycyclic Aromatic Hydrocarbons (PAHs), Total Petroleum Hydrocarbons (TPHs) and trace metals in surface sediments and pearl oyster -Pinctada radiata- was conducted in samples collected from 3 coastal locations in Qatar: Umm Bab, Dukhan and Al-Wakra. The selected sites were expected to be dissimilar in regard to the chemical pollutant level and contaminants distribution due to the different anthropogenic activities. Initial aneuploidy levels –numerical abnormality in chromosomes- in oysters were examined between December 2015 to February 2016 through randomly selecting 140 well spread metaphases. Metaphases with 26 chromosomes were recorded as diploid or normal and the ones with less or more number of chromosomes considered aneuploidy (Ebied, 1999). The ability of the oysters to adapt in terms of chemical contaminants accumulation and aneuploidy level when moved between sites with different levels of chemical pollution was assessed in the second sampling in April 2016, and using experimental approach with three treatments (control, transplanted, and translocated). The control treatments were collected from the original site and kept there, the transplanted treatments consisted of individuals composed from the other two sites and moved to Al-Wakra and the opposite, while the translocated treatment were the ones moved from Dukhan to Umm Bab and versa vise. Statistical analysis showed significant difference between sediment in the three sites; TPHs concentrated in Umm Bab, higher concentrations of metals found in Dukhan, while PAHs concentrated the most in AL-Wakra. Hydrocarbons and metals were detected in higher doses in oyster tissues collected in first sampling comparing to those analyzed in the second sampling with consistency of accumulating same contaminants. Predation by gastropod whelks caused high mortality of oyster during the second stage of the study especially in Dukhan control while transplanted animals from Al-Wakra were the least selected by gastropods. Mortality rates in Dukhan were generally higher than in other sites, except for oysters transplanted from Al-Wakra to Dukhan. Positive correlation was found between the high levels of contaminants and aneuploidy during the first phase. Unexpectedly, to the usually observed in bivalves, there was a bigger percentage of abnormal cells with chromosomal gain (hyperdiploids) than with chromosomal loss (hypodiploids) in all treatments. Among all the treatments, transplanted oysters showed the lowest level of aneuploidy followed by translocated, then control. In other words: oysters moved from site to another, regardless of the contamination levels at origin and destination, showed some recovery from initial aneuploidy levels. Further research is needed to determine the underlying mechanisms for this pattern.

Increasing seawater temperatures are being measured worldwide, causing coral bleaching events during which the symbiosis between the coral host and its symbiotic zooxanthellae is disrupted, and a global decline in reef corals. In the Arabian Gulf where water temperatures are naturally extreme with summer maxima at 35°C and above and winter minima at 18°C and below, seawater temperature anomalies are repeatedly recorded in the summer. While Arabian Gulf corals have naturally evolved to survive at temperatures that would cause bleaching and mortality to most corals elsewhere, an increasing number of mortality events have been recorded in the Gulf (Qatar, Saudi Arabia, and the UAE) in the last decades, resulting in a substantial loss of biodiversity and coral cover, mostly in inshore environments. Efforts are being deployed locally to conserve remaining habitats and attempt the restoration of lost habitats, but to be successful, efforts need to incorporate regional species-specific traits such as the susceptibility and resistance to future bleaching. We here assess the tolerance and sensitivity of three ecologically important species from the Arabian Gulf, Acropora downingi, Porites lutea, and Dipsastraea pallida, sampled in Qatari offshore reefs in the mid-winter, by exposing them to heat stress in enclosed aquaria. Colonies were assigned to control aquaria maintained at 25°C, aquaria to be raised to 30°C, or aquaria to be raised to 36°C. After an acclimatization period, the 30°C and the 35°C aquaria were raised to their target temperature at a maximum rate of 1°C per day. During the warming period and for another three weeks, we monitored the photosynthetic activity of their symbiotic zooxanthellae twice a week with a diving-PAM fluorometer while checking for signs of bleaching. We found that the photosynthetic activity was not affected in any of the three species when the temperature was raised from 25°C to 30°C. At 34°C, the photosynthetic activity in A. downingi started declining. Once the temperature reached the 35°C target, all A. downingi colonies bleached, expelling their zooxanthellae, and died three days later. The photosynthetic activity in P. lutea and D. pallida started declining once the temperature reached 35°C and continued declining for an additional three weeks, after which P. lutea died and D. pallida recovered. The high tolerance of P. lutea and especially of D. pallida is promising for the survival of the two reef-builders in coming years, despite increasing seawater temperatures caused by climate change. However, the branching Acropora coral is not expected to respond well to any further increase of temperature, as reflected in its major regional decline in the past decades. Due to its high sensitivity, Acropora might also not be a good candidate in coral restoration projects, as it showed a high sensitivity to bleaching and the inability to survive bleaching events. However, aquarium conditions not being able to fully reflect natural conditions on the reef, further work would need to be conducted directly on the reef to determine whether other factors might be involved in assisting resistance to bleaching, survival under bleaching conditions, or recovery following bleaching. In any case, P. lutea and D. pallida would be excellent candidates in coral restoration projects, having showed a lower sensitivity to bleaching and the ability to survive for several weeks under thermal stress, therefore showing potential for a long-term survival even under warming conditions.

This study evaluated the impacts of submarine groundwater discharges (SGD) on a rocky intertidal community of South Portugal, during April–November 2011. Chlorophyll-a concentration was higher at the SGD site in respect to the Reference site. Epibenthic community structure differed between sites, with an increase in Chthamalus spp. and a decrease in macroalgae coverage at the SGD site. The abundance and body size of Mytilus galloprovincialis were consistently higher at the SGD site. During mid-spring, under potentially higher SGD and less favorable conditions for coastal phytoplankton, the ecophysiological condition of M. galloprovincialis and G. umbilicalis was also higher at the SGD site. These beneficial effects on filter-feeders and herbivores probably resulted from local increases in prey availability, supported by SGD-driven nutrient inputs. Conversely, P. depressa was not favoured by SGD, probably due to a lower dependency on algae as food. The analysis of epibenthic community structure and ecophysiological condition represents a promising approach to disentangle the ecological impacts of SGD on intertidal ecosystems. This research was funded by FREEZE (PTDC/MAR/102030/2008) and PHYTOCLIMA (PTDC/AAC-CLI/114512/2009) projects, by public funds from FTC through project UID/Multi/04326/2013. L.A.K. was supported by a PhD scholarship from the Programme Science without Borders (Conselho Nacional de Desenvolvimento Científico e Tecnológico, of the Ministry of Science, Technology and Innovation of Brazil – 237998/2012-2). F.L. hold scholarship from FCT (SFRH/BPD/108949/2015). The authors would like to express their gratitude to NASA (SST data), ESA (Chl-a data), NOAA (wind data) and Agência Portuguesa do Ambiente (aquifer piezometric level and nutrient data) and every group that works hard to provide free and high quality products for the ocean sciences community. The authors thank Judite Fernandes, who kindly provided discriminated nutrient data for ARQ groundwater and Olhos de Água intertidal springs, collected in the framework of FREEZE project, as well as Dr. José Paulo Monteiro for sharing his knowledge on Algarve SGD. Special thanks are also due to Renata Gonçalves and Isa Máximo who helped in the laboratory work. The authors would also like to thank the reviewers and editor for their constructive comments that contributed for substantially improving an earlier version of the manuscript. Scopus

Coral reefs are one of the most biologically diverse and complex marine ecosystems that are being degraded at rapid rates. This consistent steadily trend is especially critical in coastal areas that have experienced an impressive coastal development, as has been occurring in the Arabian Gulf. This Gulf harbours the coral reefs subjected to one of the most extreme environmental conditions worldwide, i.e. high salinities (often >45 psu) and high sea temperatures (> 36° during summer season), together with extensive coastal development that have altered significantly the coastal regions of Bahrain, Qatar and UAE. In these countries most of coastal coral reefs have disappeared throughout the last decades because of habitat loss and alteration; however, offshore coral reefs have been away from these extensive disturbances and they may be considered as regional hotspots of corals. Even, the massive presence of submerged structures from offshore oil and gas platforms needs to be taken into account, since preliminary exploratory field surveys have shown a rich fouling community, dominated by a high variety of sessile groups. Thus, the conservation of coral reefs and associated macroinvertebrates and fish could be enhanced by studying the unexplored artificial reefs that grow attached to submerged structures of offshore oil platforms. This objective is currently being pursued in the framework of the project “Connectivity, diversity and genetic flow between offshore natural coral reefs and oil platforms - NPRP No.: 7-1129-1-201”. We herein analyzed video footages from oil platforms located at the Al Shaheen Oil Field, ca. 90 km offshore NE Qatar. The visual assessment was done by Maersk Oil Qatar in 2014, via a remotely operated vehicle (ROV). The video recordings were done during routine inspections conducted in 20 oil platforms, located at 8 locations. A total of 2000 video files were analyzed to study the relative abundance of Al Shaheen Oil Field's macroinvertebrates, using the CATAMI (Collaborative and Annotation Tools for Analysis of Marine Imagery and Video) classification scheme. This guide has been designed to promote consistency and standards for classifying marine biota and substrata captured in underwater imagery from a broad range of depths (shallow-abyssal) and habitats (temperate reefs, corals, etc.). A total of 17 morphology-based functional groups were identified (Encrusting; Porifera, Octocorallia, Hydrozoa and Bryozoa; Turf: Hydrozoa and Bryozoa; Fleshy arborescent: Antipatharia, and Octocorallia; Hard Coral: Scleractinia; Foliaceous: Hydrozoa and Bryozoa; Barnacle: Cirripedia; Bivalve: Mollusca; Massive simple: Porifera; None Flesh Bushy: Antipatharia, and Octocorallia; Fan Simple: Antipatharia, and Octocorallia; Fan Complex: Antipatharia, and Octocorallia; Whip: Antipatharia, and Octocorallia; Bryozoa: Bryozoa; Anemone: Actiniaria; Unstalked crinoid: Crinoidea; Regular urchins: Echinoidea). The MNCR's (Marine Nature Conservation Review) SACFOR (Superabundant, Abundant, Common, Frequent, Occasional and Rare) semi-quantitative abundance scale was used to study the relative macroinvertebrate abundance. The submerged structures of the oil platforms were studied from 0-60 m depth, divided into 8 depth layers (0-10, 10-20, 20-30, 30-40, 40-45, 45-50, 50-55 and 55-60 m), with time intervals of 30 seconds per layer. PERMANOVA (Permutational Multivariate Analysis of Variance) was used to calculate the similarities among samples using the resemblance of Bray-Curtis similarity. Age and depth were the main factors structuring the sessile macroinvertebrate community in the studied platforms. In contrast, no differences in community structure were found among the platform locations, probably due to the high level of connectivity within the Al Shaheen Oil Field. A total of 8 functional groups contributed >10% to the average dissimilarity of the community (hard coral, fleshy arborescent, foliaceous, encrusting, turf, barnacles, bivalve and massive simple). A clear vertical gradient is apparent for the coverage of epibenthic macroinvertebrates, with diversity and biomass increasing with depth. Encrusting sponges and bryozoans are dominant at shallow depths. Other types of macroinvertebrates become dominant as depth increases, such as foliaceous bryozoans and hydrozans, massive sponges, bivalves, anemones, crinoids and octocorals. Fleshy arborescent octocorals (Dendronephthya sp.) and azooxanthellate scleractinian corals were frequently found on the Al Shaheen oil platforms, at depths greater than 30m. The abundance of both groups tends to increase with depth and the hard corals also tend to be more abundant on older platforms. This study clearly showed that azooxanthellate scleractinian, reef building corals are recruiting and growing on the platforms the Al Shaheen Oil Field, in some cases at high densities. Given that no specimens could be obtained, precise taxonomic identification was not possible, but their morphology suggests they belong to the Caryophylliidae family. This finding is highly significant, given that this type of corals has not previously been reported in Qatari waters. Furthermore, it clearly illustrates the potential of this type of offshore infrastructure to support the establishment of functional reef ecosystems in areas where they are degraded or were previously absent, thus contributing to offset the current net loss of this important type of natural marine habitat.

[No abstract available] The Arabian/Persian Gulf is a relatively shallow, semi‐enclosed sea at high tropical latitudes, surrounded by desert land with limited water exchange, high salinities, and extreme annual fluctuations of surface temperatures (Sheppard et al. 1992). These conditions restrict the Gulf's marine biodiversity, as demonstrated by the mushroom coral family Fungiidae (Scleractinia). In the Gulf, this family has only been known to be represented by the free‐living (unattached) species, Cycloseris curvata (Hoeksema, 1989), which is considered uncommon (Riegl et al. 2012), whereas this coral family consists of 52 described species in the entire tropical Indo‐Pacific, 40 of which are unattached (Benzoni et al. 2012). This publication was made possible by NPRP awards [NPRP 7-1129-1-201 and NPRP 8-952-1-186] from the Qatar National Research Fund (a member of the Qatar Foundation) and by the Qatar Museums Authority through the project �Research on Qatar�s geological history and present-day biodiversity� granted to Naturalis Biodiversity Center. The statements made herein are solely the responsibility of the authors. The whip coral species (Fig. 1) was identified by L. P. van Ofwegen. We thank the reviewer and editor for their constructive comments. Scopus

Submarine groundwater discharges (SGD) have been documented as contributing to the biological productivity of coastal areas, through a bottom-up support to higher trophic levels. Nevertheless, the effects on the bottom levels of the coastal food web, namely the meiofauna, are still very poorly known. The “Olhos de Agua” beach is the only area on the South coast of Portugal where submarine freshwater seepages have been identified. In this study, meiofauna assemblages in the area impacted by SGD were compared with the meiofauna from a similar area, but without SGD. Samples were taken in Spring and Summer 2011, under different hydrological regimes, aquifer recharge (after Winter) and dryness (after Spring), respectively. The major changes in the community were recorded at a seasonal level, with higher abundances and number of taxa in Spring, when compared to Summer. This may be explained by better sediment aeration during spring along with higher food availability from the sedimentation of spring phytoplankton blooms. Although no significant differences were detected by multivariate analysis on the meiofauna abundances between Control and Impact areas, pair-wise tests on the interactions between factors in number of taxa ( S ) and species richness (Margalef's d ) suggested that the discharge of groundwater stimulated an increase in meiofauna diversity. Such effect can be observed between the meiofauna assemblages from impacted and control areas and also between periods with different discharge regimes (Spring and Summer) in the impacted area. These findings highlight the role that freshwater discharges from coastal aquifers have on meiofauna assemblages and suggest that SGD contribute to enhance the transfer of energy from the lower levels of the trophic web to upper levels.

Climate changes affect marine ecosystems and the survival, growth, reproduction and distribution of species, including those targeted by commercial fisheries. The impact of climate change has been reported for many fish species, but studies focusing on the effects of climate on bivalve resources are lacking. In Portugal, the harvesting of bivalves is an old and artisanal activity, of special importance along the Algarve coast (South of Portugal). This study aims to evaluate the influence of climatic, environmental and fisheries factors on the landings of intertidal coastal lagoon and coastal bivalve species (subtidal nearshore species). The environmental and fisheries parameters considered to affect the landings of bivalves in the eastern Algarve were: fishing effort (number of fishing events), sea surface temperature, North Atlantic Oscillation (NAO) index, upwelling index, wind magnitude and direction and river discharges. Analysis of time series data using min/max autocorrelation factor analysis and dynamic factor analysis showed that, for most species, fishing effort was positively related with landings per unit effort trends in the following year. Lagoon bivalve species (Cerastoderma edule and Ruditapes decussatus) responded to different environmental variables than the coastal bivalve species (Chamelea gallina, Pharus legumen, Donax spp. and Spisula solida). Upwelling index had a significant effect on the lagoon bivalves while the NAO index, wind magnitude and direction, and river discharges only affected the coastal species. This study highlighted the need to adapt fishing effort regimes, while considering the background effects of environmental variability, in order to improve fisheries management.

Eight sandy beaches along the coastline of Qatar and four sea surface stations on the eastern coast, adjacent to Doha Bay, were surveyed between December 2014 and March 2015. Microplastics, mainly low density polyethylene and polypropylene, were found in all samples of sediments and seawater. Blue fibers, ranging between 1 and 5 mm, were the dominant type of particle present. Abundances on the sea surface varied between 4.38 × 104 and 1.46 × 106 particles·km− 2, with the highest values being consistently found 10 km offshore, suggesting the presence of a convergence zone. No significant temporal variability was detected for sea surface samples. The concentration of microplastics in intertidal sediments varied between 36 and 228 particles m− 2, with no significant differences among the 8 beaches examined. These results show the pervasiveness of microplastic pollution in coastal environments of the Arabian Gulf. Potential local sources and sinks for microplastics are discussed. We would like to thank Mariem Amor Safi for her support during sampling activities. This work was funded by Qatar University , through the Department of Biological and Environmental Sciences ( QUUG-CAS-DBES-13/14-9 ) and the College of Arts and Sciences ( QUST-CAS-SPR-14\15-30 ), and supported by the Environmental Science Center . Scopus

The combustion of fossil fuels is pushing atmospheric concentrations of carbon dioxide (CO2) to unprecedented levels. This rapid increase in atmospheric CO2 is causing global changes, with noticeable increases in temperature, sea level rise and changes to marine carbon chemistry (i.e., Ocean Acidification - OA). The today average pH of ocean surface waters has already declined by 0.1 units from pre-industrial levels. According to the IPCC representative concentration pathways (RCPs), further declines in pH are predicted until the end of the century, varying between 0.14 units and 0.43 units. OA is irreversible on short time frames and previous studies have shown the potential impacts of ocean acidification on the physiology, reproduction, immunology and behavior of marine organisms, with effects already documented in multiple species and several regions of the world, although not in the Arabian Gulf. Nevertheless, the strong environmental variability of the Arabian Gulf presents good opportunities to study the potential impacts of future global change on marine ecosystems and to investigate the underlying mechanisms governing their resistance and adaptation to future environmental extremes. In this research we are targeting the response of zooplanktonic assemblages to OA, since these are commonly used as bioindicators of environmental and climate driven impact on marine ecosystems. The approach is mainly experimental, using controlled CO2 perturbation experiments, done aboard the Qatar University research vessel “Janan”. We are specifically investigating the response of zooplankton communities to relevant scenarios of seawater acidification by CO2, in terms of assemblage composition and structure; respiration rates; and egg production rates. The first round of experiments was conducted during a 3 day cruise offshore from Doha (June 3–5, 2016); complemented with a second cruise and round of experiments (November 17–19, 2016). Results provide insightful information about zooplankton communities’ responses to high CO2 levels in seawater of the Arabian Gulf and contribute to a better understanding about the biogeochemistry of coastal marine areas in Qatar, and more broadly in the Arabian Gulf.Acknowledgments: This study is funded by QNRF through the project “Zooplankton community responses to CO2 acidification in Qatar coastal waters (UREP18-177-1-021).

Noticeable changes in global temperatures, climate and ocean carbon chemistry are the result of carbon dioxide increase in the atmosphere. This increase has been mitigated by the oceans capacity to absorb one-fourth of the carbon dioxide in the atmosphere, although this CO2 intake affects oceans carbonate chemistry [i.e., ocean acidification—(OA)]. The detrimental effect of OA in the development and shell formation has been studied in several species of bivalves, although no information is available on the wedge shell Donax trunculus, a gastronomically appreciated species and an important economical resource in several southern European countries. We evaluated the effect of pCO2 increase on hatching and early life stages of D. trunculus, considering two ocean acidification scenarios (ΔpH −0.3 and ΔpH −0.6). Our results showed that elevated pCO2 caused a delay in hatching into D-larvae and reduced larvae survival. In the extreme scenario (ΔpH −0.6), some trochophore larvae persisted to day 9 of the experiment and more abnormal larvae were produced than in the ΔpH −0.3 and control treatments. At day 5, normal veligers under extreme acidification were smaller than in other treatments, but by day 9, these differences were attenuated and the average size of normal D-larvae varied inversely to the pH gradient. Possible underlying mechanisms for these complex response patterns are discussed, including the existence of phenotypic plasticity or genetic pre-adaptive capacity in this D. trunculus population to cope with future environmental changes.

The carbonate chemistry of seawater from the Ria Formosa lagoon was experimentally manipulated, by diffusing pure CO2, to attain two reduced pH levels, by − 0.3 and − 0.6 pH units, relative to unmanipulated seawater. After 84 days of exposure, no differences were detected in terms of growth (somatic or shell) or mortality of juvenile mussels Mytilus galloprovincialis. The naturally elevated total alkalinity of the seawater (≈ 3550 μmol kg− 1) prevented under-saturation of CaCO3, even under pCO2 values exceeding 4000 μatm, attenuating the detrimental effects on the carbonate supply-side. Even so, variations in shell weight showed that net calcification was reduced under elevated CO2 and reduced pH, although the magnitude and significance of this effect varied among size-classes. Most of the loss of shell material probably occurred as post-deposition dissolution in the internal aragonitic nacre layer. Our results show that, even when reared under extreme levels of CO2-induced acidification, juvenile M. galloprovincialis can continue to calcify and grow in this coastal lagoon environment. The complex responses of bivalves to ocean acidification suggest a large degree of interspecific and intraspecific variability in their sensitivity to this type of perturbation. Further research is needed to assess the generality of these patterns and to disentangle the relative contributions of acclimation to local variations in seawater chemistry and genetic adaptation.

10 páginas, 3 tablas, 1 figura, Coastal ocean acidification is expected to interfere with the physiology of marine bivalves. In this work, the effects of acidification on the physiology of juvenile mussels Mytilus galloprovincialis were tested by means of controlled CO2 perturbation experiments. The carbonate chemistry of natural (control) seawater was manipulated by injecting CO2 to attain 2 reduced pH levels: −0.3 and −0.6 pH units as compared with the control seawater. After 78 d of exposure, we found that the absorption efficiency and ammonium excretion rate of juveniles were inversely related to pH. Significant differences among treatments were not observed in clearance, ingestion and respiration rates. Coherently, the maximal scope for growth and tissue dry weight were observed in mussels exposed to the pH reduction ΔpH = −0.6, suggesting that M. galloprovincialis could be tolerant to CO2 acidification, at least in the highly alkaline coastal waters of Ria Formosa (SW Portugal)., This is a contribution to the ‘The integrated impacts of marine acidification, temperature and precipitation changes on bivalve coastal biodiversity and fisheries: how to adapt?’ project, which is part of the CIRCLE Med projects, funded by the Regional Ministry of Innovation and Industry of the Galician Government (08MDS 018402PR), the Italian Ministry for Environment, Land and Sea, and the Foundation for Science and Technology of Portugal (ERA-CIRCLE/0004/2007), in the framework of the Circle ERA Net project (which is funded by the European Commission 6th Framework Programme).

Excluding particular species or guilds of grazing gastropods from experimental areas on intertidal rocky shores is a manipulation frequently used by marine ecologists. Manual removals, cages or fences are classical methods, but they usually require large areas or multiple procedural controls to avoid experimental artefacts. In order to minimise some of those constraints, alternative methods have been developed and are increasingly being used. The effects and limitations of these methods are, however, generally assumed and hardly ever tested. The experiment described here was designed to compare the effectiveness of manual removals, copper paint and sticky barriers in excluding intertidal grazing gastropods from experimental areas on a natural sandstone platform in South-eastern Australia. The response of the grazing assemblage was evaluated for individual species and collectively (integrating all species) by direct counts of individuals and from radular marks on wax discs. The observed patterns varied considerably among species. As predicted, barriers of copper paint effectively excluded the limpet Cellana tramoserica, for several weeks, while having no apparent effect on co-occurring species of grazing gastropods. Sticky barriers were also effective in excluding C. tramoserica, but for shorter periods of time. Contrary to expectations, however, sticky barriers were generally incapable of deterring the coiled snails Bembicium nanum and Nerita atramentosa. Barriers of copper paint are, therefore, a cost-effective way to manipulate diversity (densities of individuals, number and composition of species) and function (intensity of grazing) in this type of assemblage. Care must be taken to clarify the underlying mechanisms and to identify adequate procedural controls.

Coral reefs represent one of the most biologically and socio-economically important natural assets in the Arabian region, particularly in Qatar. Stress through increasing sea temperatures and salinities, growing development, and other pressures, has resulted in shifts in reef communities across the region in recent years. Branching corals have disappeared from most reef systems while previously thriving inshore reefs are being reduced to rubble with little signs of life remaining. We here conduct a thorough re-assessment of coral reefs around Qatar, focusing on coral cover and biodiversity using photoquadrat surveys, and we investigate potential environmental drivers of coral communities in the region. Results show higher coral cover on offshore reefs than on inshore reefs. Additionally, among previously documented inshore corals reefs, several have lost their coral cover and have shifted to non-coral ecosystems composed of rubble, turf algae, and oysters. Coral diversity is higher on offshore reefs than inshore reefs, with previously reported species now absent on inshore reefs. Environmental factors such as salinity and sea surface temperatures could play an important role in driving current patterns of coral biodiversity and biogeography and in predicting their shift as a function of future regional climate scenarios. We expect inshore reefs to be generally more fragile and susceptible to stress due the higher variability in environmental conditions. These same inshore reefs are also the most exposed to human interactions and coastal development. To ensure the future of coral reefs in the region and to sustain their ecosystem services, coral reefs in Qatar will need to be effectively regulated (i.e. through the development and implementation of an ecosystem-based management plan). In addition, recovery of impacted reefs could be assisted through the creation of a network of marine protected areas (MPAs), allowing for natural replenishment of coral communities through connectivity. In the meantime, local reefs are likely to continue their decline in coral cover and diversity, particularly the inshore environments.

The use of field reflectance spectrometry to detect and quantify chlorophyll-a in intertidal epilithic micro-algae is evaluated. Sandstone disks were placed into intertidal areas for different amounts of time to accumulate micro-algae. Field reflectance spectra (350–1050 nm) were acquired from each of the disks before and after they were collected from the intertidal zone. Pigments were extracted from the sandstone disks using methanol and chlorophyll-a concentration was determined spectrophotometrically. Other pigments were identified using High Performance Liquid Chromatography (HPLC). Different ratios of reflectance were tested. A ratio of reflectances at 750 and 670 nm (R750 / R670) had the tightest correlation with chlorophyll-a (R2 = 0.93; SE = 1.14; P = Absorptions due to chlorophylls a, b and c, carotenoids and the phycobiliproteins phycoerythrin, phycocyanin and allophycocyanin were identified. The techniques described here enable estimation of amounts of chlorophyll-a and the detection of several other pigments. Thus, investigations of microflora in studies of succession, biofilms or grazing in intertidal habitats can be enhanced by field spectrometry.

من المتوقع أن يخضع الساحل الشمالي الشرقي القطري في المستقبل القريب لتغييرات التي تفرضها الضغوطات البشرية )مشاريع التنمية الساحلية( . يتألف هذا الساحل من النباتات المتنوعة والحيوانات حساسة )مثل الشعاب المرجانية ، ومروج الأعشاب البحرية والسلاحف ( لذلك هناك حاجة ملحة إلى دراسة الآثار المترتبة على مثل هذه الثغيرات على النظم الإيكولوجية. النماذج الإيكولوجية ، هي عبارة عن تمثيلات رياضية و نظرية للنظام الطبيعي، التي أدخلت على فهم الخصائص الوظيفية للنظام البيئي الحقيقي تحت تاثيرات فيزيائية معروفة تمثل النظام المدروس . باستخدام البيانات التي تم جمعها من حقول او من الجمعيات البيئية لبناء نموذج النظام البيئي الوظيفي الذي يحاكي البيئة الحقيقية . ثم يتم استخدام هذه النظم كنموذج من أجل مساعدة تقييم تأثير السيناريوهات المستقبلية على الأنظمة الحقيقية . الهدف من هذه الدراسة هو خلق المحاكاة الهيدروديناميكية جنبا إلى جنب مع نموذج نقل الرواسب لتمتد من الساحل قبالة جبل فويرط . وقد تحقق هذا الهدف باستخدام برنامج GEMSS لصناعة النماذج، و الذي يتطلب البيانات التالية للحصول على نموذج السليم 1( البيانات الفضائيه ) كملفات من نظام ( ArcGIS (، الذي يتضمن الخط الساحلي للمنطقة وقياس الأعماق، بالإضافة إلى المواقع، الارتفاعات، و تشكيلات الهياكل التي من صنع الإنسان . . (2) البيانات التي تستند على الوقت، والتي هي متفاوتة في الوقت المناسب )أي تغيرات المد والجزر، ومعدل التدفق ودرجة الحرارة وبيانات الأرصاد الجوية( . (3) تكوين الرواسب. تم صنع النموذج الهيدروديناميكي لمحاكاة ميكانيكيات المياة والتحقق من صحة البيانات بمقارنتها مع بيانات حقليه . بالإضافة إلى ذلك, تم صنع نموذج نقل الرواسب الذي يحدد مصير الرواسب العالقة في المنطقة وتحديد أحتمل حدوث التعرية اوالترسيب في اي منطقة اخرى . أظهرت النتائج لكل من النموذج الهيدروديناميكي والنموذج نقل الرواسب أن منطقة الدراسة هي منطقة ديناميكية للغاية، يتم التحكم بها بشكل رئيسي من قبل المد والجزر وأن احتمال التعريه للرواسب تتزايد في الحدود الشمالية والشرق والغرب . يوفر هذا العمل ثلاثة سيناريوهات للتنميه المستقبلية التي قد تحدث في هذه المنطقة، ويظهر تغيير ديناميكيات المياه والرواسب وفقا لذلك . وفقا لذلك خرجنا بمجموعة من التوصيات لصناع القرار لتحسين إدارة المنطقة الساحلية . كما أنه يوفر الأدوات التي يمكن تكرارها في الدراسات الهيدروديناميكية في المستقبل على طول المنطقة الساحلية القطرية .

There has been a tremendous proliferation in plastic production in the last five decades due to its low cost and versatile applications. Plastic debris dominates the marine litter globally and has been found in the most pristine environment including the abysmal region of the world ocean. Studies show that over 8 million tons of plastics are dumped in the ocean annually (Gregory, 2009). Plastics are persistent in the environment and take several decades to degrade especially in the ocean. Large plastic debris can heavily damage the coral reefs and may cause entanglement, choking, blockage of digestive tracts when ingested by turtles, whales, sharks etc, causing several thousand deaths annually among these organisms. Microplastics are tiny plastic particles that seldom originate from fragmentation of large plastic debris or are produced to serve some specific purposes. Microplastics pose greater threats as they can be mistaken for food by filter-feeders and planktivorous fish, and can also adsorb large quantities of recalcitrant organic pollutants (OPs). Impacts on marine biota may include endocrine disruption, carcinogenesis, and sexual disruption, etc. These impacts may not always be obvious but OPs surely affect marine biota once they enter the food web even at low concentrations (Mato et al., 2001) which biomagnify up the marine food web, hence, explains the need for their investigation.In this study, the spatial and temporal distribution of microplastics was investigated for the first time in Qatar; both in sediments and seawater. Eight beaches across Qatar and four sea surface stations were surveyed between the months of December 2014 and March 2015. The objectives of this study were:1. To analyze the spatial and temporal variability of microplastics in seawater and sediments, in sea surface and intertidal sandy beach environments, respectively.2. To characterize the isolated microplastics based on size, shape, colour, and type of polymer.3. To describe macroplastics collected from beaches based on polymer type and quantify the concentration of OPs adsorbed on their surfaces.4. To investigate the rate of adsorption of OPs on virgin plastic pellets in a field experiment.A general overview of the followed methodologies is given in Appendix 1. In the first phase of this study, the spatial and temporal distribution of microplastics was investigated in seawater and sediments respectively. Four sea surface stations (Appendix 2) and eight beaches (Appendix 3) across Qatar were surveyed between the months of December 2014 and March 2015.Seawater was sampled respectively with a surface neuston net (300 μm mesh size) towed off the side of the speedboat in undisturbed water for 5 minutes at 1.5 knots (Doyle et al., 2011). Next, collected materials in the cod were transferred into labeled, acid-treated insulated glass containers to prevent contamination. Concentrations of microplastics were given in square meters as sampling was done in two-dimensional air-sea interface. Physicochemical parameters (temperature, salinity, pH and dissolved oxygen) were measured in-situ and recorded at each sampling site.Additionally, eight coastal stations (Al Dhakhira, Ras-Laffan, The Pearl, Doha Bay, Al Ruwais, Dukhan, Umm Bab, and Mesaieed) were chosen on the basis of their accessibility and being evenly distributed along Qatar coastline.For each sampling, sediments from the top 2 cm were collected at the most recent high tidal mark on shore from a square area (0.5 × 0.5 m) along the shore line. Three replicate quadrats (5 meters apart) were sampled in each beach. The samples were homogenized and transferred into acid-treated glass containers to prevent contamination and transported to the laboratory for analyses.Microplastics (Appendix 4) were discovered in all samples and their abundance varied both in intertidal sandy beaches and sea surface. Two-factor ANOVA revealed that the spatial variability of microplastics in sea surface stations was statistically significant however, there was no observable temporal variability (Appendix 5). The average concentration of microplastics in all 8 beaches was not significantly different (Appendix 6). Chemical analysis revealed the occurrence of OPs with endocrine effects on all obtained macroplastics, and concentration of pollutants was consistent in all sites. Large piece-to-piece variations of contamination up to two orders of magnitude were discovered within sites (2 to 1,005 ng/g), although there was no significant difference in contaminant concentration among all sites for PCBs and PAHs respectively.Since plastic debris are hydrophobic and easily adsorb organic pollutants the second phase of this study was targeted at investigating the concentration of PCBs and PAHs adsorbed on macroplastics in situ. Field adsorption/desorption experiment was performed to investigate how pellets of different polymers and contaminated with POPs behave when placed in ambient seawater. Pellets were deployed and later retrieved at 48h, 96 h, 192 h, and 312 h respectively. The pellets were analyzed for PCBs and PAHs and undeployed pellets were also analyzed at time 0. Adsorbed PCBs and PAHs concentration showed a steady decrease with time, suggesting that contaminated pellets ending in the marine environment release their adsorbed contaminants in less contaminated seawaters revealing a complex OPs dynamic between plastics an seawater as a function of differential concentrations of pollutants and environmental conditions.This study is the first of its kind in Qatar and seemingly in the entire Arabian Gulf region. Marine pollution is a growing concern in Qatar coastal and offshore environment. Marine debris is of major concern due to the fact that plastic can take several decades to be fully degraded. Results from this study indicate that microplastics are ubiquitous in Qatar coastal environment and the fact that they are easily mistaken for food and ingested by zooplankton and smaller fishes makes them a serious threat to the marine food web. Hence, regular monitoring of the occurrence of microplastics and studying how they may affect the foodweb and potential contaminations of exploited (seafood) species are needed to give policy makers an insight of the sources of the debris and proffer suggestions on how to tackle the menace using a holistic approach.ReferencesDoyle, M.J., Watson, W., Bowlin, N.M., Sheavly, S.B., 2011. Plastic particles in coastal pelagic ecosystems of the Northeast Pacific ocean. Marine Environmental Research 71, 41–52.Gregory, M.R., 2009. Environmental implications of plastic debris in marine settings: entanglement, ingestion, smothering, hangers-on, hitch-hiking and alien invasions. Philosophical Transactions of the Royal Society B: Biological Sciences 364, 2013–2025.Mato, Y., Isobe, T., Takada, H., Kanehiro, H., Ohtake, C. and Kaminuma, T. 2001. Plastic Resin Pellets as a Transport Medium for Toxic Chemicals in the Marine Environment. Environmental Science & Technology 35 (2), 318–324.

Zooplanktons are marine animal members of the planktonic community. They play a key role in marine ecosystem, by linking primary production to higher trophic levels. The spatial and temporal dynamics of zooplankton communities were studied in 4 station along a transect offshore of Doha Bay, Qatar, from June 2014 to March 2015. Zooplankton samples were collected by means of horizontal tows using 120 and 500μm mesh size plankton nets. Two methods of examination were used and intercalibrated: optical microscopy and the automated identification and counting equipment FlowCAM. No spatial variability was observed among the locations sampled, while temporal variability was detected. The faunistic groups contributing most to these temporal variations were Cladocera, Oikopleura, crab larvae, Lucifer typus, fish eggs, and jellyfish. Our results showed no significant differences between the use of either the automated (FlowCAM) or the optical identification and counting suggesting the possible use of both methodologies as they provide complementary information (accurate identification capabilities and size spectra or population structure data).

12 páginas, 3 tablas.-- P. Range ... et al., The effects of seawater acidification caused by increasing concentrations of atmospheric carbon dioxide (CO2), combined with other climatic stressors, were studied on 3 coastal Mediterranean bivalve species: the mussel Mytilus galloprovincialis and the clams Chamelea gallina and Ruditapes decussatus. CO2 perturbation experiments produced contrasting responses on growth and calcification of juvenile shells, according to species and location. In the Northern Adriatic (Italy), long-term exposure to reduced pH severely damaged the shells of M. galloprovincialis and C. gallina and reduced growth for the latter species. Seawater in the Ria Formosa lagoon (Portugal) was consistently saturated in carbonates, which buffered the impacts on calcification and growth. After 80 days, no shell damage was observed in Portugal, but mussels in the acidified treatments were less calcified. Reduced clearance, ingestion and respiration rates and increased ammonia excretion were observed for R. decussatus under reduced pH. Clearance rates of juvenile mussels were significantly reduced by acidification in Italy, but not in Portugal. Both locations showed a consistent trend for increased ammonia excretion with decreasing pH, suggesting increased protein catabolism. Respiratory rates were generally not affected. Short-term factorial experiments done in Italy revealed that acidification caused alterations in immunological parameters of adult bivalves, particularly at temperature and salinity values far from the optimal for the species in the Mediterranean. Overall, our results showed large variations in the sensitivities of bivalves to climatic changes, among different species and between local populations of the same species. Expectations of impacts, mitigation and adaptation strategies have to consider such local variability., Funding was provided by the Foundation for Science and Technology (FCT) of Portugal (ERA- CIRCLE/0004/2007), the Regional Ministry of Innovation and Industry of the Galician Government, and the Italian Ministry for Environment, Land and Sea, in the framework of Circle ERA Net project (which is funded by the European Commission 6th Framework Programme). PR was also supported by a post-doctoral grant from FCT (SFRH/BPD/ 69959/2010)

The distribution, abundance and recruitment of Chthamalus species were studied for one year at two rocky shores on the central coast of Portugal. Chthamalus montagui is the most abundant intertidal barnacle on the Portuguese mainland. Higher abundance of C. montagui was found on the lower levels of the more sheltered shore, which is closer to the influence of the Tagus estuary. Chthamalus stellatus was also present, in very low densities, and always confined to the lower level of the barnacle zone. Chthamalus stellatus was more common at the shore farther away from the estuary, in which exposure to wave action is higher. The metamorphs of C. stellatus settled at the studied shores are considered to be immigrants from other populations, where the density of adults is sufficient for cross-fertilization to occur. Chthamalus spp. recruited almost continuously throughout the year, with a peak between July and September and a gap during February and March. Variations in phytoplanktonic assemblages and temperature may be the main factors controlling the reproductive season of Chthamalus spp. Recruitment was usually stronger on the lower shore levels but extended for a longer period higher on the shore. Seasonalvariations of C. montagui abundance were greater on the lower levels of the more exposed shore. This is probably due to faster growth and higher mortality of barnacle populations occupying the lower shore levels at the more exposed habitats.

The influence of submarine groundwater discharges (SGD) on the dynamics ofcoastal ecosystems is receiving increasing scientific attention, although ourknowledge of this issue still remains insufficient. Understanding the ecologicalresponse of coastal ecosystems to SGD dynamics is important in order to eval-uate and predict changes in coastal communities. The aim of the present studywas to characterize the effect of groundwater discharge on subtidal soft-bottommacrofaunal assemblages in the south coast of Portugal (Algarve) at differenttimes of the year and under different discharge regimes. Sediment macrofaunawas sampled twice per season in spring and summer 2011 in two locations:one under influence of SGD (Olhos de Agua) and one not under that influence(Arrifes). The results showed that differences in community structure betweenlocations occurred mainly during spring, when the magnitude of groundwaterdischarge was higher. Several individual taxa were strongly associated with theSGD, particularly during spring: the polychaete families Magelonidae andOweniidae; the isopod Cyathura carinata;andthebivalvesTellimya ferruginosaand Tellina fabula. Some of these taxa are already considered indicators of SGD,whereas others merit further investigation. The average similarity among sam-ples was consistently larger in the location with SGD and the average similaritybetween the two locations was generally higher during spring, indicating thatSGD promote stability in macrobenthic communities across time and space.SGD were also associated with higher values of Chlorophyll a (Chl a), fine sed-iments and total abundance of organisms (particularly suspension feeders).This suggests that differences between locations are associated with SGD andmediated by nutrient fluxes and sediment transport, or their interaction.IntroductionSubmarine groundwater discharges (SGD) may representan additional source of freshwater to the coastal zonesince they are a widespread natural phenomenon that canoccur whenever an aquifer is hydraulically connected tothe coastal zone by permeable sediments and the head ofthe aquifer is above sea level (Johannes 1980). Alreadycalled ‘subterranean estuaries’ (Moore 1999), SGD canaccount for as much as 10% of the total freshwater inputto the coastal zone, with seepage areas acting as zones ofmixing of fresh and saltwater (Burnett et al. 2003). Therole of SGD in modulating salinity and as a supply ofsediments chemical compounds (e.g. nutrients, carbonand pollutants) into coastal areas is already well docu-mented (e.g. Johannes 1980; D’Elia et al. 1981; Valiela

We used a controlled CO2 perturbation experiment to test hypotheses about changes in diversity, composition and structure of soft-bottom intertidal macrobenthic assemblages, under realistic and locally relevant scenarios of seawater acidification. Patches of undisturbed sediment were collected from 2 types of intertidal sedimentary habitat in the Ria Formosa coastal lagoon (South Portugal) and exposed to 2 levels of seawater acidification (pH reduced by 0.3 and 0.6 units) and 1 unmanipulated (control) level. After 75 d the assemblages differed significantly between the 2 types of sediment and between field controls and the ex situ treatments, but not among the 3 pH levels tested. The naturally high values of total alkalinity buffered seawater from the changes imposed on carbonate chemistry and may have contributed to offsetting acidification at the local scale. Observed differences on biota were strongly related to the organic matter content and grain-size of the sediments, particularly to the fractions of medium and coarse sand. Soft-bottom intertidal macrofauna was significantly affected by the stress of being held in an artificial environment, but not by CO2-induced seawater acidification. Given the previously observed variations in the sensitivities of marine organisms to seawater acidification, direct extrapolations of the present findings to different regions or other types of assemblages do not seem advisable. However, the contribution of ex situ studies to the assessment of ecosystem-level responses to environmental disturbances could generally be improved by incorporating adequate field controls in the experimental design. Scopus

Oceans face a serious change to their natural biogeochemical cycle due to the rapid absorption of CO 2 generated by human activities. Ocean acidification is the common term used to describe the decrease of seawater pH caused by the absorption of atmospheric CO 2 . To evaluate the effects of ocean acidification, we focused on the larval stage of bivalves, which produce a fragile calcareous skeletal structure, very sensitive to changes in seawater chemistry. In this context, we investigated sperm motility, fertilization rate and larval viability (survival, growth and abnormalities) of the Pacific oyster, Crassostrea gigas , a commercially important bivalve, in a controlled CO 2 perturbation experiment. The carbonate chemistry of seawater was manipulated by diffusing pure CO 2 , to attain two reduced pH levels (ΔpH = − 0.4 and ΔpH = − 0.7) which were compared to unmanipulated seawater. The results show high sensitivity of C. gigas veliger larvae to low values of pH, as reflected by a decrease in survival and growth rates, as well as an increased frequency of prodissoconch abnormalities and protruding mantle. Moreover, results also show that sperm motility, fertilization rate, and hatching success, were negatively influenced by acidification. The exposure to ΔpH = − 0.7 had a higher impact on the fertilization and larval viability than ΔpH = − 0.4. The results suggest that the reproductive success and the biological mechanisms for calcification may be prematurely interrupted and disturbed when C. gigas veliger larvae are exposed to an acidified environment which may reduce their viability and compromise settlement and future abundances of this species.