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Population outbreaks of zoantharians in shallow water reefs have been observed globally, including intertidal and subtidal sites in the Canary Islands. This study investigated how zoantharians might be integrating into the local trophic network. For that purpose, we assessed the feeding patterns of common species in zoantharian-dominated habitats, focusing on finding consumers of Zoanthus pulchellus and Palythoa caribaeorum. Through DNA-barcoding and metabarcoding, the gut contents of 11 predatory species were analysed, aiming to characterize their diets and explore local species feeding on zoantharians. Analyses of diet revealed a diverse range of food items and trophic positions of some of the most common and frequent marine species in the archipelago. Furthermore, based on previous observations on the different impacts of Z. pulchellus and P. caribaeorum on shallow benthic ecosystems of the Canary Islands, a preliminary approach to identify their potential influence on feeding patterns of associated species was made. Even though DNA-metabarcoding did not detect zoantharians in the gut contents of any studied species, Sanger sequencing with zoantharian-specific primers indicated their consumption by subject species may be limited to only the crab Platypodiella picta. In addition, by focusing on some of the most common species, this study enhances our understanding of the local trophic network and provides an insight into trophic dynamics in zoantharian-dominated habitats. [ABSTRACT FROM AUTHOR]

The isopod crustaceans reported from or expected to occur in littoral and sublittoral marine habitats of the Southern California Bight (SCB) in the northeastern Pacific Ocean are reviewed. A total of 190 species, representing 105 genera in 42 families and six suborders are covered. Approximately 84% of these isopods represent described species with the remaining 16% comprising well-documented "provisional" but undescribed species. Cymothoida and Asellota are the most diverse of the six suborders, accounting for ca. 36% and 29% of the species, respectively. Valvifera and Sphaeromatidea are the next most speciose suborders with between 13-15% of the species each, while the suborder Limnorioidea represents fewer than 2% of the SCB isopod fauna. Finally, the mostly terrestrial suborder Oniscidea accounts for ca. 5% of the species treated herein, each which occurs at or above the high tide mark in intertidal habitats. A key to the suborders and superfamilies is presented followed by nine keys to the SCB species within each of the resultant groups. Figures are provided for most species. Bathymetric range, geographic distribution, type locality, habitat, body size, and a comprehensive list of references are included for most species. [ABSTRACT FROM AUTHOR]

This work describes the structure of the assemblage of bivalve mollusks (i.e., composition, abundance, density, distribution and species diversity) of four representative rocky beaches of Mazatlan bay, Mexico. Biological samples were taken in the upper intertidal, lower intertidal and shallow subtidal of the beaches together with environmental parameters: type of sediment, organic matter, water temperature, dissolved oxygen, wave exposure and concentration of chlorophyll a. A total of 19,848 individuals distributed in 77 species, 50 genera and 27 families were recorded. The permutational ANOVA and PERMANOVA indicated significant differences in the bivalve assemblage structure among environments across studied sites. However, the intertidal (IT) and SS environments had different bivalve assemblages. Six species had a broad distribution: Acar rostae, Arcopsis solida, Isognomon janus, Saccostrea palmula Chama buddiana and Carditamera affinis. Four species had the highest density in the IT: Brachidontes semilaevis (196.0 ind m2), B. adamsianus (35.0 ind m2), Arcopsis solida (18.0 ind m2) and Lithophaga aristata (15.0 ind m2), and in the SS were Lithophaga aristata (7.1 ind m2), B. semilaevis and Acar rostae (3.2 ind m2). This study shows that exposure to waves was determinant for the bivalve distribution that inhabit the intertidal zone. In contrast, chlorophyll a and organic material are the variables that best explain the distribution of the species in the SS. However, more detailed information is required regarding the importance of the interaction between the hydrodynamics and the topography of the rocky beaches of Mazatlan bay. [ABSTRACT FROM AUTHOR]

The muricid gastropod Acanthina monodon deposits egg capsules in both subtidal and intertidal environments. Intertidal egg capsules are naturally exposed during low tides to sublethal environmental stressors, including desiccation and fluctuations in temperature and salinity. This study was undertaken to determine if juveniles hatching from intertidal egg capsules show reduced rates of feeding or growth. This research therefore compares the performance of juveniles during the first month of post-hatching life, according to whether the juveniles had developed in capsules that had been naturally deposited intertidally or subtidally. We found that juveniles that hatched from intertidal egg capsules grew more slowly than those that hatched from subtidally collected capsules. Moreover, juveniles that hatched from intertidal egg capsules consumed fewer prey per week and ate more slowly than those that hatched from subtidal capsules, although by the end of the study, the total dry weight of juveniles from the two environments was no longer significantly different. Even so, the final mean organic content of juveniles that had hatched from subtidal capsules was significantly higher than that of juveniles that had hatched from capsules of intertidal origin, suggesting that the juveniles from intertidal egg capsules prioritized inorganic shell growth over tissue growth. These results suggest that the intertidal placement of egg capsules imposes stresses on embryos that subsequently reduce rates of juvenile feeding and shell growth, demonstrating how sublethal stresses experienced during early, pre-hatching development in the field interacting with likely maternal effects can produce deleterious latent effects in later life. [ABSTRACT FROM AUTHOR]

Three infaunal apodid sea cucumbers collected in Kushimoto, Shirahama, and Susami, in the southern coast of Wakayama, Japan are described. They have different morphological characteristics in body color, ossicle arrangement, and internal organs, each other. First species, animal displays a large body size (approximately 70–150mm) and pale body color (semitransparent pink with anterior tip brownish) was found out. Second species, animal displays a small body size (approximately 20mm) and pale body color (transparent yellow) with whitish wheel-papillae on three dorsal interradii was found out. Third species, animal displays a moderate body size (approximately 20–35mm) and deep red or reddish brown body color with dark yellowish wheel-papillae on three dorsal interradii was found out. All three species having 10 tentacles, sigmoid-hook ossicles, and wheel ossicles in their body wall, turned out to be belonging to the genus Taeniogyrus Semper, 1867, and new to science. [ABSTRACT FROM AUTHOR]

Spatially discrete stocks that vary in life history traits on a reef‐to‐reef scale present a challenge for fisheries managers. Nationally or regionally applied one‐size‐fits‐all approaches to management fail to account for this variability, and when coupled with fishing pressure this can result in serial depletion and localized extinction.Where mechanisms for local management exist, as they do in New Zealand via customary protection areas (Taiāpure Local Fisheries, Mātaitai Reserves), managers have the opportunity to trial tools on scales relevant to the stocks managed. This study assesses the effect of bag limits and a rāhui (temporary closure) in managing the spatially discrete, and culturally important, blackfoot abalone (Haliotis iris, pāua) in the East Otago Taiāpure, in southern New Zealand.Using surveys spanning 8 years and 26 sites, the rāhui was found to have had mixed results: halting the decline in pāua density at 0 m but not 0.5 m depths. The rāhui did, however, result in an increase in the percentage of individuals above the minimum legal size at both depths.Where bag limits alone had been applied, pāua densities and the percentage of legal‐sized individuals continued to decline over the 8‐year period, with the loss of large individuals, translating into a decline in estimated egg production.Growth estimates from mark–recapture and surveys of juvenile abundance at sites inside and outside the rāhui highlight the fine‐scale variability in pāua life history even within this local area. This suggests there may be biological impediments to pāua management using bag limits alone.Though pāua restoration efforts have had mixed results to date, this study highlights the potential for legally empowered local managers and communities to respond to fisheries declines in their own local area in an action‐driven, adaptable, and timely way. [ABSTRACT FROM AUTHOR]

Biodiversity is crucial for maintaining ecosystem stability and functionality under increasing anthropogenic stress. Part of this resilience comes from having many species performing the same function (functional redundancy) leading to the quantification of community composition and functional redundancy in relation to increasing stress. However, much of the research within coastal ecosystems focuses on distinct areas, rather than whole ecosystems. Here, we investigate the relationship between biodiversity and functional redundancy across two environmental gradients (sediment mud content and water column depth) and different habitat types following a survey of benthic macrofauna and sediment characteristics at 24 sites within Whangārei Harbour, New Zealand. We observed strong gradients in biodiversity which fragmented communities into fewer species that were a subset of the wider community. The lowest biodiversity was observed at muddy, intertidal and shallow subtidal sites which also had the lowest predicted functional redundancy. We show the stronger influence of water column depth on predicted functional redundancy than sediment mud content, highlighting the importance of subtidal regions. Overall, our study highlights the importance of studying the individual contributions of different areas in a landscape to characterise effective colonist pool size and how this can be used to predict recovery potential following disturbance.

A rapidly accumulating body of research has shown that species diversity consistently affects the functioning of ecosystems. The incorporation of trophic complexity and the extension of this research to larger scales and natural ranges in species diversity remain as important challenges for understanding the true magnitude of these effects in natural systems. Here, we test whether the diversity of prey communities affects the magnitude of aggregate consumer effects. We conducted a meta-analysis of 57 consumer removal field experiments from a range of intertidal and subtidal hard substrate marine communities. We found that the richness of the prey community was the strongest predictor of the magnitude of consumer effects while controlling for habitat type, taxonomic composition, and other variables. Consumer removal increased aggregate prey abundance on average by 1200% at the lower limit of prey diversity (two species), but only 200% at the upper limit of 37 species. Importantly, compositional change was substantial at both high and low prey diversity, suggesting predation intensity did not vary with prey richness. Rather diverse prey communities appear to be more capable of maintaining abundance via compensatory responses, by containing prey species that are resistant to (or tolerant of) predators. These results suggest that the effects of species diversity on trophic interactions may scale consistently from small-scale manipulations to cross-community comparisons.

Historic hunting has led to severe reductions of many marine mammal species across the globe. After hunting ceased, some populations have recovered to pre-exploitation levels and may have regained their prominent position as top predator in marine ecosystems. Also, the harbor seal population in the international Wadden Sea grew at an exponential rate following a ban on seal hunting in 1960s, and the current number ~38,000 is close to the historic population size. Here we estimate the impact of the harbor seal predation on the fish community in the Wadden Sea and nearby coastal waters. Fish remains in fecal samples and published estimates on the seal's daily energy requirement were used to estimate prey selection and the magnitude of seal consumption. Estimates on prey abundance were derived from demersal fish surveys, and fish growth was estimated using a Dynamic Energy Budget model. GPS tracking provided information on where seals most likely caught their prey. Harbor seals hauling-out in the Dutch Wadden Sea fed predominantly on demersal fish, for example, flatfish species (flounder, sole, plaice, dab), but also on sandeel, cod, and whiting. Although harbor seals acquire the majority of prey further offshore in the adjacent North Sea, and only spend 14% of their diving time in the Wadden Sea, seal predation was still estimated to cause an average annual mortality of 43% of the remaining fish in the Wadden Sea and 60% in the nearby shallow coastal waters (<20 m). There were however large sources of uncertainty in the estimated impact of seals on fish, including the migration of fish between the North Sea and Wadden Sea, and catchability estimates of the fish survey sampling gear, particularly for sandeel and other pelagic fish species. Our estimate suggested a considerable top-down pressure by harbor seals on demersal fish. However, predation by seals may also alleviate density-dependent competition between the remaining fish, allowing for increased fish growth, and partly compensating for the reduction in fish numbers. This study shows that recovering coastal marine mammal populations could become an important component in the functioning of shallow coastal ecosystems. [ABSTRACT FROM AUTHOR]

Fluctuating asymmetry (FA) consists of random deviations from perfect symmetry, and it is a useful trait to monitor developmental stability and ecological stress. The principal goal in this work was to study shell shape FA in Mytilus platensis as a measure of stress of living in intertidal wild areas compared to subtidal cultured ones. Shell shape asymmetry was studied by geometric morphometrics using landmarks and semilandmarks from internal and external anatomical structures. We analyzed FA comparing shell shape from 452 individuals living at different habitats (intertidal rocky shores vs. subtidal longlines) in two Patagonian sites. We predict that mussels living in the intertidal present higher levels of morphological alterations (i.e., FA) than those from the subtidal, where the environmental stress is lower. We based the asymmetry analysis on the FA scores from Procrustes ANOVA; all effects of the model were statistically significant. The Procrustes FA scores differed significantly between habitats: intertidal populations presented higher FA scores than subtidal ones. As predicted, shell shape in Mytilus platensis is influenced by the habitat and these differences add evidence to the fact that FA is a suitable measure of developmental instability, indicating the inability of species to buffer stress in its developmental pathways. [ABSTRACT FROM AUTHOR]

Abstract: In modern siliciclastic environments terrestrial and aquatic vegetation binds substrate, controls weathering and erosion rates, influences run‐off, sediment supply and subsequent depositional architecture. This study assesses the applicability of modern depositional models that are impacted by vascular vegetation, as analogues for ancient pre‐land plant systems. A review of pre‐Devonian published literature demonstrates a paucity of described tidal successions; this is possibly due to the application of modern analogues for interpreting the record when there is a lack of tidal indicators. This paucity suggests a need for revised models of tidal deposition that consider the different environmental conditions prior to land plant evolution. This study examines the Ordovician–Silurian Tumblagooda Sandstone, which is exposed in the gorge of the Murchison River and coastal cliffs near Kalbarri, Western Australia. The Tumblagooda Sandstone comprises stacked sand‐rich facies, with well‐preserved bedforms and trace fossils. Previous interpretations of the depositional setting have proposed from a mixed sheet‐braided fluvial and intertidal flats; to a continental setting dominated by fluvial and aeolian processes. An enigmatic element is the rarity of mud‐rich facies preserved in the succession. Outcrop logging, facies and petrographic analysis record dominantly shallow water conditions with episodes of emergence. Abundant ichnotaxa indicate that marine conditions and bi‐directional flow structures are evidence for an intertidal and subtidal depositional environment. A macrotidal estuary setting is proposed, with evidence for tidal channels and repeated fluvial incursions. Physical and biogenic sedimentary structures are indicative of tidal conditions. The lack of clay and silt resulted in the absence of flaser or lenticular‐bedding. Instead cyclic deposition of thin beds and foreset bioturbation replaced mud drape deposits. Higher energy conditions prevailed in the absence of the binding activity of plants in the terrestrial and marine realm. This is suggestive of different weathering processes and a reduction in the preservation of some sedimentary features. [ABSTRACT FROM AUTHOR]

The aim of the study was to increase knowledge regarding baseline biology of Arctic mussels (Mytilus spp.) in terms of lipid class content at different stages of reproductive development throughout the year. Lipid composition in the mantle and digestive glands were studied in mussels from the intertidal and subtidal zones of mussel beds located in the Norwegian Sea and the White Sea. Thin-layer chromatography was used to quantify phospholipids, triacylglycerols, sterols and their esters. The differences in climatic and hydrological conditions between the studied geographical locations of mussel beds were reflected not only in the timing and duration of the mussel’s reproductive stages, mainly active gametogenesis (stage II) and maturity (stage III), but also in the lipid composition of mussel mantle and digestive gland. The differences in environmental conditions between intertidal and subtidal zones of the studied mussel beds were also reflected in the lipid composition of mussels from both geographic locations, and determined the modifications of their lipid composition during the reproductive development. Although environmental conditions caused specificity in the distribution of the lipid composition in the mantle and digestive gland of Arctic Mytilus spp., the lipid composition variations that accompany the reproductive processes in bivalve mollusks were not affected. [ABSTRACT FROM AUTHOR]

The porcellanid crabs are diverse and abundant species inhabiting the intertidal and subtidal rocky substrate. One particular species is Allopetrolisthes punctatus, a medium-sized crab, poorly studied but strikingly abundant in some places of Chile. Near Chome (central Chile) large aggregations have been reported by local fishermen. A direct population assessment with semi-autonomous scuba diving was performed to evaluate stock structure, distribution, and abundance. A monthly monitoring was established to analyze the temporal variability of biological traits during a one-year time period. Dense crab aggregations were observed over the naked unprotected rocky substrate, with corporal size and sexual proportion spatially segregated. Allopetrolisthes punctatus showed a relatively high fecundity (164-8,741 eggs) and uninterrupted yearly spawning, which seems to favor the quick and successful settlement for this species in Chome. [ABSTRACT FROM AUTHOR]

High-resolution benthic foraminiferal study was carried out on the surficial bottom sediments of the Al-Kharrar Lagoon (KL), north of Rabigh City, eastern Red Sea coast, Saudi Arabia. One hundred thirty surface sediments samples were collected from the lagoon during March 2014 to investigate the benthic foraminiferal diversity, abundance, distribution and controlling factors. The lagoon'swater environmental parameters such as temperature, salinity, dissolved oxygen and pH,water depth, sediment grain size, organic matter and carbonate were also studied. Statistical techniques were applied to test the reliability of collected data and to facilitate the interpretation. The results showed that faunal density and diversity were with averages of 135±300 dead tests/g and 23±10 displaying the highest values (3000 and 44) only in some intertidal areas, respectively. The Q-mode cluster analysis as well as the spatial distribution of the benthic foraminifera allowed the division ofKLinto five environmental biotopes such as the southern tip, the mid-eastern side, the inlet, the whole intertidal-subtidal and, the deeper area. These biotopeswere dominated by five major assemblages such as an intertidal assemblage (Quinqueloculina seminula-Q. laevigata and Affinetrina quadrilateralis-Neorotalia calcar), an inlet Amphistegina lessonii assemblage, an intertidal-subtidal assemblage (Peneroplis planatus-Coscinospira hemprichii-Sorites orbiculus) and deep-water assemblage (Spiroloculina communis-Triloculina serrulata-T. trigonula). The canonical correspondence analysis indicated that the intertidal-subtidal assemblage is positively correlated with high salinity, temperature, and bioclastic sandy substrates with algal mats, sea-grasses and macro-algae, reflecting their preferences to warm, dry climatic conditions. The deep-water assemblage showed positive relationships with pH, deep muddy substrates enriched in organic matter, and negatively correlated with high temperature and salinity. The inlet assemblage is also correlated with the deeper waters where hard to coarse-grained substrates predominate. [ABSTRACT FROM AUTHOR]

This study tested for differences in the composition of intertidal and shallow subtidal rocky reef habitats subjected to a range of human pressures across ∼1000 km of coastline in New South Wales, Australia over 5 years. Percentage covers of habitats were sampled using aerial photography and a large grain size (20 m 2 intertidal; 800 m 2 subtidal) in a nested hierarchical design. Results were consistent with anthropogenic impacts on habitat structure only around estuaries with the most heavily urbanised or agriculturally-intense catchments. The most convincing relationships documented here related to environmental variables such as SST, latitude, reef width and proximity to large estuaries irrespective of human disturbance levels. Moreover, there were suggestions that any influences of estuarine waters (be they anthropogenic or natural) on reef assemblages could potentially extend 10s of kilometres from major estuaries. In general, our results supported those of studies that utilised smaller grain sizes (greatest variability often at smallest spatial scales), but we found that variability over scales of 100s of km can be similar to or greater than variability over scales of 10s of metres. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Biologia Marina y Oceanografía (RBMO) is the property of Universidad de Valparaiso, Facultad de Ciencias del Mar and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Environmental conditions induce phenotypic responses (behavioural, morphological and physiological) in many marine species. The boring mytilidLeiosolenus patagonicusinhabits different types of substrata, such as sandstone intertidal and hard subtidal substrata (here called ‘lifeless-substratum’) and shells of bivalve species (here called ‘live-substratum’), where they are exposed to different restrictions in their growth. We used geometric morphometric methods to compare the contour shell shapes from each type of substratum (live and lifeless) since we expected the body shape to differ between individuals from these different substrata. The results showed that the shell shape depends on the type of substratum where the larvae recruit. The mean shell shapes of individuals from the live-substratum are more slender than those of the individuals growing inside the lifeless-substratum. Individuals from live-substratum can adapt their phenotype depending on the oyster’s anti-parasitism responses, while in lifeless-substratum they are able to build their own refuges. [ABSTRACT FROM PUBLISHER]

Since the mid-1980s major changes in spatiotemporal patterns of distribution of juvenile plaice have occurred in the Wadden Sea. Large juvenile (I- and II-group) plaice have almost completely disappeared from the intertidal flats in spring and summer and are no longer found in subtidal and tidal channels in autumn, consistent with an offshore movement reported in the nearshore coastal zone. In this paper we evaluate the present functional importance of the western Wadden Sea as a nursery for young-of-the-year (0-group) plaice and the changes over time compared to the mid-1980s period by analyzing abundance, growth and distribution patterns in various intertidal, subtidal and tidal channel areas. Spatiotemporal changes in habitat use were observed compared to 1986 based on a depth-stratified sampling repeated two decades later, in 2009. Present results showed that the utilization of the western Wadden Sea has greatly changed, with changing patterns of depth distribution of the 0-group. Settlement of 0-group plaice still occurred in the intertidal, however, shortly thereafter, they moved to deeper waters. Such shift in habitat use did not seem to have affected growth rates. Overall, it seems that the western Wadden Sea can still support young-of-the-year plaice population and in spite of changes in habitat use, the functional importance of the area for this group has not been affected. [ABSTRACT FROM AUTHOR]

Baggett et al. (2015) identified a set of three universal environmental variables to be monitored for evaluating all oyster habitat restoration projects: salinity, temperature, and dissolved oxygen. Perhaps evidencing a bias toward subtidal reefs, this set of parameters omits another first-order environmental factor, tidal emersion. Intertidal oyster reefs can be the dominant reef habitat in estuaries, with clear zonation in oyster performance across the intertidal exposure gradient. Therefore, we propose to include tidal emersion as a fourth universal environmental parameter when designing and evaluating oyster restoration projects to better encompass the whole environmental spectrum along which reefs occur. [ABSTRACT FROM AUTHOR]

La diversidad de macroinvertebrados marinos ha recibido una atención creciente, no obstante, con un escaso tratamiento en el contexto biogeográfico. Este estudio analiza los registros de 1.601 especies de macroinvertebrados bentónicos pertenecientes a: Demospongiae, Anthozoa, Polychaeta, Mollusca, Crustacea, Echinodermata y Ascideacea, agrupados en 10 zonas y tratados desde una perspectiva zoogeográfica. Mollusca (611 especies), Polychaeta (403) y Crustacea (370) corresponden a los grupos mejor representados a lo largo de la costa chilena, determinantes en el patrón global de la biodiversidad. Este aumenta suavemente de norte a sur, interrumpido por máximos que sugieren esfuerzos diferenciales de estudio más que un comportamiento natural de la biodiversidad. El grado de agrupamiento entre las zonas muestra las tres unidades biogeográficas definidas recientemente por Lancellotti & Vásquez. Este arreglo, que representa lo exhibido por los grupos más diversos, se ve alterado en los grupos menos representados donde las diferencias obedecen al patrón de afinidades mostradas por las zonas comprendidas dentro de la Región Templada Transicional. El quiebre zoogeográfico alrededor de los 41º S, sugerido largamente en la literatura, sólo ocurre en Echinodermata y Demospongiae, evidenciando en los otros taxa la existencia de un área de transición entre los 35º y 48º S, caracterizada por un reemplazo gradual de especies. Dentro de las regiones la biodiversidad muestra homogeneidad, contrario al endemismo, el que alcanza un máximo de 52% en la Región Templada Fría y que parece ser consecuencia del alto número de especies con registros únicos (38,2% de especies citadas para una sóla zona). Esto sugiere un desconocimiento de los macroinvertebrados chilenos (distribución y diversidad), sobrestimando el endemismo regional y distorsionando los patrones locales de biodiversidadThe diversity of marine macroinvertebrates has received increasing attention, although with little emphasis on its biogeographical significance. The present study analyses an updated data base on 1,601 littoral benthic species, belonging to: Demospongiae, Anthozoa, Polychaeta, Mollusca, Crustacea, Echinodermata y Ascideacea, whose records grouped into 10 zones, have been studied from the zoogeographic perspective. The groups best represented along the Chilean coast include the Mollusca (611 species), Polychaeta (403) and the Crustacea (370), with an important influence on its general pattern of biodiversity. This biodiversity showed a mild but progressive increase along the latitudinal gradient from north to south, interrupted by maxima which appear to reflect differences in study effort rather than normal behavior. The degree of relationship between zones showed three faunistic units recently defined by Lancellotti & Vásquez. This arrangement, which was evident in the most diverse groups, became altered in the lesser speciose groups where differences obeyed a pattern of affinity to particular zones within the Transitional Temperate Region. The presence of a zoogeographic break near 41º S, as broadly suggested in the literature, was only seen in data for the Echinodermata and the Demospongiae; other taxa show the existence of a region of transitional character having gradual replacement of species. Within the Regions, the biodiversity showed great homogeneity, contrary to endemism, which reached 52% in the Cold Temperate Region, as a consequence of an important number of single species records (38.2% species recorded in only one zone). This represents the present lack of knowledge of the Chilean fauna, probably overestimating regional endemism, and thus distorting knowledge of local patterns of biodiversity

Thirty species of sea cucumbers (holothuroids) are recorded from the Johor Straits based on the Comprehensive Marine Biodiversity Survey between December 2010 and April 2014. Specimens were collected by hand at intertidal sites and by trawling and dredging at subtidal sites. A total of 193 lots of specimens were examined, which comprised 30 species from four orders and seven families. Of these, five species have previously been documented from Singapore, 11 are new records for Singapore, ten are potential new species, and four are unconfirmed at species level. The new records and possibly new species represent six families: five species of Synaptidae, i.e., Anapta gracilis (Semper), Protankyra pseudodigitata (Semper), Protankyra species, Synaptula recta (Semper) and Synaptula reticulata (Semper); one species of Holothuriidae, i.e., Holothuria (Metriatyla) albiventer (Semper); three species of Cucumariidae, i.e., Colochirus species, Leptopentacta imbricata (Semper) and Mensamaria intercedens (Lampert); five species of Phyllophoridae, i.e., Stolus species, Thorsonia adversaria (Semper), Thyone species a, Thyone species b, and Thyone species c; two species of Psolidae, i.e., Psolidium species a and Psolidium species b; two species of Sclerodactylidae, i.e., Cladolabes hamatus (Sluiter) and Globosita species; three species of Caudinidae, i.e., Acaudina leucoprocta (H. L. Clark), Acaudina molpadioides (Semper) and Acaudina species. These new records and possible new species attest to the still poorly documented state of biodiversity in the Malayan archipelago. The holothuroid fauna of the muddy estuarine habitat in the Johor Straits is surprisingly diverse. [ABSTRACT FROM AUTHOR]

This study aims to investigate the periodicity of shell microgrowth lines and increments of cockles in the intertidal and subtidal areas. A total of 600 marked specimens of the blood cockle Anadara granosa were placed in buried cages that were placed at three sites of differing water levels (Site A: exposed in all low tides, Site B: exposed during spring tides, and Site C: continuously immersed) in Pinang Island, Malaysia. Cockles were collected on a fortnightly basis and the shells were sectioned from the umbo to the ventral margin, before being polished, etched and photographed under a light microscope to observe microgrowth lines and increments. The majority of the cockle shells examined showed that the number of growth lines in shell structures was close to the number of tidal emersions ( P > 0.01). The number of microgrowth lines observed in shells during the study period was significantly different ( P < 0.01) from the number of days and tidal changes. Similarly, cockles grown in the laboratory in a simulated tidal regime, deposited a number of microgrowth bands which coincided with the number of tidal emersions. This study shows that shell microgrowth lines are typically formed in accordance with tidal emersions, providing a calendar base for high resolution environmental reconstructions. Endogenous activity synchronised by tidal cues may control rhythmic microgrowth line formation in subtidal areas. [ABSTRACT FROM AUTHOR]

In this study the effect of inputs of organic matter and anthropogenic nitrogen at small spatial scales were investigated in the benthos of the Ria of A Coruña (NW Spain) using stable carbon and nitrogen isotopes. This ria is characteristically enriched in nutrients provided either by marine processes (as coastal upwelling) or by urban and agricultural waste. Stable isotope composition in trophic guilds of infaunal benthos revealed spatial differences related to their nutrient inputs. The main difference was the presence of an additional chemoautotrophic food web at the site with a large accumulation of organic matter. The enrichment in heavy nitrogen isotopes observed in most compartments suggests the influence of sewage-derived nitrogen, despite large inputs of marine nitrogen. Macroalgae ( Fucus vesiculosus ) resulted significantly enriched at the site influenced by estuarine waters. In contrast, no differences were found in mussels ( Mytilus galloprovincialis ), thus suggesting a major dependence on marine nutrient sources for this species. However, the estimations of anthropogenic influence were largely dependent on assumptions required to model the different contributions of sources. The measurement of stable isotope signatures in various compartments revealed that, despite anthropogenic nutrients are readily incorporated into local food webs, a major influence of natural marine nutrient sources cannot be discarded. [ABSTRACT FROM AUTHOR]

Abstract: Highly mobile predators such as fish and crabs are known to migrate from the subtidal zone to forage in the intertidal zone at high-tide. The extent and variation of these habitat linking movements along the vertical shore gradient have not been examined before for several species simultaneously, hence not accounting for species interactions. Here, the foraging excursions of Carcinus maenas (L.), Necora puber (Linnaeus, 1767) and Cancer pagurus (Linnaeus, 1758) were assessed in a one-year mark-recapture study on two replicated rocky shores in southwest U.K. A comparison between the abundance of individuals present on the shore at high-tide with those present in refuges exposed at low-tide indicated considerable intertidal migration by all species, showing strong linkage between subtidal and intertidal habitats. Estimates of population size based on recapture of marked individuals indicated that an average of ~4000 individuals combined for the three crab species, can be present on the shore during one tidal cycle. There was also a high fidelity of individuals and species to particular shore levels. Underlying mechanisms for these spatial patterns such as prey availability and agonistic interactions are discussed. Survival rates were estimated using the Cormack-Jolly-Seber model from multi-recapture analysis and found to be considerably high with a minimum of 30% for all species. Growth rates were found to vary intraspecifically with size and between seasons. Understanding the temporal and spatial variations in predation pressure by crabs on rocky shores is dependent on knowing who, when and how many of these commercially important crab species depend on intertidal foraging. Previous studies have shown that the diet of these species is strongly based on intertidal prey including key species such as limpets; hence intertidal crab migration could be associated with considerable impacts on intertidal assemblages. [Copyright &y& Elsevier]

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Sculpin fishes of the North American Pacific Coast provide an ideal opportunity to examine whether adaptive morphological character shifts have facilitated occupation of novel habitat types because of their well-described phylogeny and ecology. In this group, the basal-rooted species primarily occupy the subtidal habitat, whereas the species in the most distal clades are found in the intertidal. We tested multiple evolutionary models to determine whether changes in body size and changes in number of scales are adaptive for habitat use in sculpins. Based on a statistically robust, highly resolved molecular phylogeny of 26 species of sculpins, in combination with morphometric and habitat affinity data, our analyses show that an adaptive model based on habitat use best explains changes in body size and number of scales. The habitat model was statistically supported over models of neutral evolution, stabilizing selection across all habitats, and three clade-based models. We suggest that loss of scales and reduction of body size in the intertidal may facilitate cutaneous breathing in air when tidepools become hypoxic during low tides. This study demonstrates how the combined use of phylogenetic, ecological and statistical approaches helps to identify traits that are likely adaptive to novel habitats. [ABSTRACT FROM AUTHOR]

Abstract: With 92 species along the North American Pacific Coast, marine sculpins represent the most species-rich radiation of fishes in this region. I used the mitochondrial cytochrome b gene and the nuclear ribosomal S7 intron for 99 species (76 North American, 19 Asian, and four North Atlantic) to produce the most complete phylogenetic hypothesis yet generated for this assemblage. Maximum likelihood and Bayesian analyses produced highly similar tree topologies. While many previously proposed groupings based on morphology are recovered, the molecular data suggest that a number of genera are para- or polyphyletic. However, this analysis supports the monophyly of one large clade that is found exclusively along the North American Pacific Coast (Chitonotous–Ruscarius–Artedius–Orthonopius–Clinocottus–Leiocottus–Oligocottus). Some sibling species have disjunct ranges, suggesting allopatric speciation. However, many other sibling species have largely overlapping ranges, and repeated habitat shifts appear to have facilitated diversification. [Copyright &y& Elsevier]

Meiofaunal assemblages from intertidal and shallow subtidal seabeds were studied at two sites (one dominated by volcanic sands and the other by organogenic sands) at Tenerife (Canary Islands, NE Atlantic Ocean) throughout an entire year (May 2000--April 2001). Specifically, we aimed (i) to test for differences in diversity, structure, and stability between intertidal and subtidal meiofaunal assemblages, and (ii) to determine if differences in the meiofaunal assemblage structure may be explained by environmental factors (granulometric composition, availability of organic matter, and carbonate content in sediments). A total of 103,763 meiofaunal individuals were collected, including 203 species from 19 taxonomic groups (Acari, Amphipoda, Cnidaria, Copepoda, Echinodermata, Gastrotricha, Isopoda, Insecta, Kinorrhyncha, Misidacea, Nematoda, Nemertini, Oligochaeta, Ostracoda, Polychaeta, Priapulida, Sipuncula, Tanaidacea, and Turbellaria). Nematodes were the most abundant taxonomic group. Species diversity was higher in the subtidal than in the intertidal zone at both sites, as a result of the larger dominance of a few species in the intertidal zone. The meiofaunal assemblage structure was different between tidal levels at both sites, the intertidal presenting greater temporal variability (multivariate dispersion) in the meiofaunal assemblage structure than the subtidal. Sediment grain size, here quantified by the different granulometric fractions, explained the variability in meiofaunal assemblage structure to a greater extent than the percentage of carbonates, a variable linked to sediment origin. This study revealed differences in diversity, assemblage structure, and variability between intertidal and subtidal meiofauna. [ABSTRACT FROM AUTHOR]

A surprisingly high number of shallow water sponge species (197) were recorded from extensive sampling of natural intertidal and subtidal habitats in Singapore (Southeast Asia) from May 2003 to June 2010. This is in spite of a highly modified coastline that encompasses one of the world's largest container ports as well as extensive oil refining and bunkering industries. A total of 99 intertidal species was recorded in this study. Of these, 53 species were recorded exclusively from the intertidal zone and only 45 species were found on both intertidal and subtidal habitats, suggesting that tropical intertidal and subtidal sponge assemblages are different and distinct. Furthermore, only a third of the fouling species of sponges from a previous study was recorded in this study, thus suggesting that sponge assemblages from natural and fouling communities in the tropics are different as well. A new species, Forcepia (Forcepia) vansoesti is described from Singapore. Members of this genus possess unique spicules shaped in the form of a pair of forceps. The new species is distinguished from its congeners in having the largest forceps (nearly 300 μm in length) so far recorded in the Indo-Pacific. [ABSTRACT FROM AUTHOR]

Abstract: The Santanyí Limestone, a 30–35-m thick upper Miocene limestone succession cropping out in Mallorca, contains abundant microbialite deposits, the shape, microstructure and texture of which was controlled by environmental factors: depth, energy and salinity. Three main types of microbialites are distinguished: (1) domed (DNOS) and stratiform, mostly undulate (UNOS) non-oolitic stromatolites, (2) undulate oolitic laminites (UOL) and (3) domed-oolitic thrombolites (DOTs). Based on lithofacies associations and occurrence of microbialite types, the Santanyí Limestone succession is subdivided into five stratigraphic units (I to V) separated by sharp surfaces. Within units II, III and V, the vertical evolution of microbialites was induced by changes in accommodation space/depth: (1) intertidal/very-shallow subtidal conditions at the base were induced by flooding over a wide area, (2) continued sea-level rise caused submergence to subtidal conditions, and (3) a significant bathymetric decrease created the sharp surface bounding these units. In units II and III, NOS accumulated in variable energy and depth conditions, as buildups with thick, somewhat discontinuous and mostly non-isopachous lamination, surrounded by oolitic grainstones with wave and current structures and oolitic intraclasts. In contrast, thin and generally regular and smooth lamination of NOS in unit V suggests, along with the absence of oolite grainstones and macrobiota, calm and restricted, maybe more saline, conditions. UOL, consisting of oolitic layers separated by thin micritic laminae, developed adjacent to NOS in units II and III and to DOT at the lower part of unit III, in shallow-water and low-energy conditions. Both ooids and micrite laminae have evidence for biogenesis. Micritized ooids containing microbial remains are common. Micritic laminae in UOL and the dark micritic laminae in NOS are thought to represent bacterially enhanced calcite precipitation and lithification during periods of low sedimentation. Oolitic thrombolites containing macrobiota are only present in unit III. They represent deeper and open-marine conditions affected by high-energy events, in which microbially mediated precipitation favoured microbialite accretion and lithification. [Copyright &y& Elsevier]

The article presents a study that investigated the relationship between sudden changes or thresholds in marine ecosystems and the theory of multiple stable states to determine how thresholds can occur in parameters, processes and ecosystem states. Researchers showed that thresholds and hysteresis-like behavior are possible in linear systems using a 2-species Lotka-Volterra model of competition. They also addressed the confusion caused by the different meanings of thresholds by reviewing the concept of thresholds within the context of multiple stable states.

Abstract: The phylum-level meta-analysis approach was applied to assess the status of disturbance of intertidal and subtidal macrobenthos in two estuaries in northeastern Brazil that are subject to different sources of pollution. Previously published estuarine data were included in the body of knowledge considered in the meta-analysis, to improve the reliability of the assessment of the Brazilian samples. Further multivariate and distributional techniques were applied to discriminate differences between estuaries and assess the pollution status of each. Phylum-level multivariate comparisons based on community attributes succeeded in discriminating the estuaries, and species distributions against abundance separated the estuaries in terms of pollution status. The meta-analysis indicated an almost indistinguishable moderate pollution status for both systems. Addition of new comparative data to the meta-analysis did not improve its sensitivity. Although the meta-analysis yielded satisfactory results in detecting disturbance in tropical estuaries, the method is not very sensitive to differences in sources of pollution. [Copyright &y& Elsevier]

1. Positive species interactions are increasingly recognized as important drivers of community structure and ecosystem functioning. Although the literature on facilitative interactions in terrestrial environments has been reviewed and emerging patterns have been synthesized, comparable attempts are lacking for the marine realm. 2. By means of a quantitative survey of the literature, I provide a critical summary of current knowledge on positive species interactions in marine environments. In particular, I (i) assess how marine facilitation research compares to that carried out in terrestrial environments in terms of focus and philosophical approach; (ii) illustrate the mechanisms by which facilitation takes place in different habitats; (iii) assess whether benefactor and beneficiary species are more likely to belong to the same or to a different trophic level; and (iv) provide examples of how including facilitation into ecological theory might advance our understanding of the mechanisms that regulate ecosystem functioning. 3. Except for some studies in intertidal habitats, few studies in marine environments have been framed within mainstream facilitation theory (e.g. the Stress Gradient Hypothesis) and research does not seem to be organized in a self-contained theme. Amelioration of physical conditions appears to be the most common mechanism of facilitation in intertidal habitats, whilst associational defence predominates in the subtidal. 4. In contrast to the terrestrial literature, dominated by plant–plant interactions, marine benefactors and beneficiary species often belong to different trophic levels. This might imply little overlapping of resource niches or a differential response to environmental conditions or consumer pressure, with implications for the persistence of facilitative effects at the extreme ends of stress gradients. 5. Recent research shows that facilitation can enhance temporal variability and invasibility of marine communities and emphasizes the central role of positive species interactions in regulating the functioning of natural ecosystems. 6. Synthesis. Studies encompassing a wide variety of life histories and environmental conditions are central to achieving a unified facilitation theory. Research in marine environments can provide new insights into the mechanisms underlying variations in the strength and direction of species interactions, but this will require greater awareness and consideration of facilitation. [ABSTRACT FROM AUTHOR]

Abstract: Estuaries consist of a complex mosaic of many distinctive habitat types. Each one may perform several vital functions in the functioning of the whole system and although its value is often based on species density patterns, functional relationships between them also need to be examined. Spatial patterns of estuarine habitat use by fish assemblages were determined within and among nine estuarine systems along the Portuguese coast. Fish sampling surveys were conducted in May and July 2006, covering the full estuarine gradient. All the different habitat types were sampled in each estuarine system with a beam trawl. Estuarine habitats were mapped with GIS and habitat specific associated fish assemblages were described based on several community descriptors, namely richness (S), evenness (J′), and diversity (H′) and on an ecological and feeding guilds classification. A canonical correspondence analysis was performed to evaluate the relationship between estuarine habitats and fish assemblages in this set of estuaries. The intertidal and subtidal soft substratum habitats corresponded to the largest areas in all the estuaries and presented higher number of species. Nevertheless the highest mean density of fish was registered at the salt marsh habitat, which occupies smaller areas within each estuary. The fact that small vegetated habitats like salt marsh and seagrass supported high densities of fish may be an indication of the important role these habitats play in the whole system functioning. Differences in fish assemblage structure were found with latitude and between habitats amongst and within estuaries. Some of the fish species were found to be particularly associated with certain habitat types, which might indicate that each estuarine habitat may be related with specific fish assemblages regardless the estuary. The present work provides valuable information for management by identifying the most important habitats for species conservation and predicting the possible effects of habitat disturbance or destruction, namely by climate change and anthropogenic pressures. [Copyright &y& Elsevier]

Marine ecosystems in the Arctic and Antarctica were once thought pristine and away from important human influence. Today, it is known that global processes as atmospheric transport, local activities related with scientific research bases, military and touristic maritime traffic, among others, are a potential source of pollutants. Macroalgae have been recognized as reliable metal-biomonitoring organisms due to their accumulation capacity and physiological responses. Metal accumulation (Al, Cd, Cu, Fe, Pb, Zn, Se, and Hg) and photosynthetic parameters (associated with in vivo chlorophyll a fluorescence) were assessed in 77 samples from 13 different macroalgal species (Phaeophyta; Chlorophyta; Rhodophyta) from areas with high human influence, nearby research and sometimes military bases and a control area, King George Island, Antarctic Peninsula. Most metals in macroalgae followed a pattern influenced by rather algal lineage than site, with green seaweeds displaying trends of higher levels of metals as Al, Cu, Cr and Fe. Photosynthesis was also not affected by site, showing healthy organisms, especially in brown macroalgae, likely due to their great dimensions and morphological complexity. Finally, data did not demonstrate a relationship between metal accumulation and photosynthetic performance, evidencing low anthropogenic-derived impacts associated with metal excess in the area. Green macroalgae, especially Monostroma hariotti, are highlighted as reliable for further metal biomonitoring assessments. In the most ambitious to date seaweed biomonitoring effort conducted towards the Austral pole, this study improved by 91% the overall knowledge on metal accumulation in macroalgae from Antarctica, being the first report in species as Sarcopeltis antarctica and Plocamium cartilagineum. These findings may suggest that human short- and long-range metal influence on Antarctic coastal ecosystems still remains under control. [Display omitted] • Accumulation of eight metals was investigated in Antarctic seaweeds. • Photosynthesis varied upon algal lineage but not metal content. • Photosynthesis was enhanced in brown macroalgae due to dimensions and complexity. • Green macroalgae arise as reliable metal-biomonitoring organisms for Antarctica. • Metals in macroalgae cannot be attributed to human-mediated pollution. [ABSTRACT FROM AUTHOR]

Abstract: A comparative survey of the anaerobic survival potential of four different bivalve species and the interference of associated bacteria has been carried out. Individuals from both subtidal and intertidal environments were considered by selecting the following species: Mytilus edulis (subtidal epifaunal), Spisula subtruncata (subtidal infaunal), Macoma balthica (intertidal infaunal) and Cerastoderma edule (intertidal infaunal). Anaerobiosis was simulated in the laboratory by subjecting individuals to the following conditions: nitrogen atmosphere, air atmosphere and anoxic seawater incubation. Moreover, the effect of the antibiotic CA (chloramphenicol) was investigated, either as a pre-treatment of individuals kept under normoxic conditions for a week or directly added to the anoxic incubation media. According to survival performances of the individuals, intertidal animals that use to cope with tidal fluctuations in the coastline (emersion processes) had an extraordinary greater capacity to survive aerial exposure as compared to both nitrogen gas and anoxic seawater incubations most likely due to their capacity to perform aerobiosis at certain rate from atmospheric oxygen availability. Specifically, Macoma balthica enlarged its survival potential up to 24.8 days (LT50) under air exposure at 12 °C as compared to other specific treatments used here (4.9 days). The latter pattern was also observed, although in a much lower magnitude, for the other intertidal species Cerastoderma edule that survived 3.7 and 4.6 days (LT50) under nitrogen atmosphere and anoxic seawater incubation, respectively as compared to 9.5 days for emersed individuals. In contrast to the subtidal species, aerial exposure of both intertidal species led to a much higher survival performances than incubation of individuals in anoxic media with the presence of antibiotic. Survival capacity of the subtidal species Mytilus edulis and Spisula subtruncata was statistically similar under air and nitrogen atmospheres and anoxic seawater incubation. Then, subtidal species have a limited ability to air breathing as a conclusion of a similar survival in atmospheric and anoxic seawater incubations. Remarkably, M. edulis represented the only exception when considering longer-term survival capacity compared to the LT50 values. Indeed, differences in LT90 values for M. edulis were statistically different, values decreasing significantly from 19.7–19.9 days (under both nitrogen and air atmospheres) to 16.7 days when individuals are incubated in anoxic seawater. This may be due to the adverse effects of anaerobic bacteria that spontaneously proliferate within the static seawater incubations. As well as for S. subtruncata, possible aerobic processes under aerial exposure of mussels seemed to be not significant for the enlargement of its survival potential, since results obtained for both air and nitrogen atmospheres are similar. Pre-treatment with the antibiotic chloramphenicol caused survival capacity to increase by a factor of approx. 2 (M. edulis) and 34–44% (S. subtruncata). In contrast to intertidal species, the direct addition of the antibiotic to the incubation media caused the highest survival performances in both subtidal species. Habitat differences and species-dependent variability must be considered as significant sources of variation when studying the anaerobic performance of individuals using the most common experimental anaerobic techniques to test survival potential. [Copyright &y& Elsevier]

Abstract: Despite the great importance of shallow rocky communities (<30m deep) due to their contribution to the biodiversity of coastal waters, most efforts in ecological status assessment of marine waters have been carried out in the implementation of soft bottom biotic indices. Therefore, in this paper, a methodology for the environmental evaluation of coastal rocky communities for the Bay of Biscay (NE Atlantic), the CFR index (Quality of Rocky Bottoms), is presented. This index is based on the analysis of seaweed communities throughout the depth gradient, from the intertidal to the shallow subtidal, through the combination of a multimetric approach, which combines the richness of characteristic macroalgae populations, their total cover, the presence of opportunistic species and the physiological condition of the whole macroalgae community. Quality thresholds for these indicators are based on both ecological data and expert judgment. Finally, a preliminary application of this metric to sites with theoretically good and bad environmental conditions is used to analyze the suitability of the index. As a result, the four selected indicators responded in a significant way to the pressure gradient tested, proving to be appropriate for the type of pressure analysed and obtaining coherent results in the final quality assessment with the CFR index. In conclusion, the CFR index has proved to be an effective tool for the assessment of the ecological quality of coastal rocky communities, based on the analysis of macroalgae assemblages. [Copyright &y& Elsevier]

Wadden Sea tidal flats are highly dynamic regarding the spatial distribution and the grain size composition of their sediments. From 2003 to 2006 surface sediments have been surveyed in an intertidal and a subtidal area within the tidal inlet Königshafen (south-eastern North Sea, northern Wadden Sea, island of Sylt) with the goal to gain information on short-term development trends in the grain size composition. The average grain size (Mean) becomes finer in the sheltered part of the intertidal survey area whereas a coarsening tendency can be observed in the more exposed part of the intertidal and especially in the subtidal survey area. The trend of the most frequent grain size (first Mode) shows the same spatial distribution pattern but is far less distinct. Thus, the changing Mean must be related to an increase in the deposition of fines in the sheltered part of the intertidal Königshafen as well as a general removal of fine-grained material in the exposed intertidal and subtidal Königshafen. In order to see long-term trends the surveys of 2003-2006 were compared to earlier studies conducted in 1932/1933, 1981 and 1989. A significant depletion of mud can be observed in the entire survey area. It is concluded that primarily changed hydrodynamics that may accompany ongoing climate change are responsible for this. However, the loss of fine-grained sediments is additionally amplified by a reduced vegetation cover and coastal protection measures. [ABSTRACT FROM AUTHOR]

We report the composition of terrestrial, intertidal and shallow sublittoral faunal communities at sites around Rothera Research Station, Adelaide Island, Antarctic Peninsula. We examined primary hypotheses that the marine environment will have considerably higher species richness, biomass and abundance than the terrestrial, and that both will be greater than that found in the intertidal. We also compared ages and sizes of individuals of selected marine taxa between intertidal and subtidal zones to test the hypothesis that animals in a more stressed environment (intertidal) would be smaller and shorter lived. Species richness of intertidal and subtidal communities was found to be similar, with considerable overlap in composition. However, terrestrial communities showed no overlap with the intertidal, differing from previous reports, particularly from further north on the Antarctic Peninsula and Scotia Arc. Faunal biomass was variable but highest in the sublittoral. While terrestrial communities were depauperate with low biomass they displayed the highest overall abundance, with a mean of over 3 × 105 individuals per square metre. No significant differences in ages of intertidal and subtidal individuals of the same species were found, with bryozoan colonies of up to 4 years of age being present in the intertidal. In contrast with expectation and the limited existing literature we conclude that, while the Antarctic intertidal zone is clearly a suboptimal and highly stressful habitat, its faunal community can be well established and relatively diverse, and is not limited to short-term opportunists or waifs and strays. [ABSTRACT FROM AUTHOR]

Most Atlantic and Gulf coast U.S. states with an oyster fishery have operated some form of oyster reef enhancement program over the past 50 years. Although programs were initially only directed at oyster fisheries augmentation, recent emphasis has shifted to include the restoration of their ecological functions. Furthermore, many of these programs are managed by environmental organizations or state agencies not traditionally involved in fisheries management or research, but rather in ecological restoration, monitoring, and/or environmental education. A simple assessment of shellfish meetings over the past five years, including the inaugural Restore America's Estuaries meeting from which this paper is derived, revealed more than 300 presentations related to oyster restoration, with fewer than 25% focused solely on oyster fishery restoration. Unfortunately, many of those efforts lacked well-defined "success criteria," with progress often judged using fisheries-based metrics such as market-sized (generally 75 mm or 3") oysters. Here we discuss our findings as they relate to the value of alternative restoration metrics and associated success criteria using data from two very different systems and approaches: one conducted in Virginia's lower Chesapeake Bay (Rappahannock River), based on data from a two-year program utilizing subtidally constructed reefs of different reef "scale," and the other a long-term study in South Carolina focusing on intertidal reefs. For each system, we compared newly created reef structures, relating oyster abundance and size to resident species abundance and biodiversity over time. Our results revealed positive correlations between several community descriptors and the size and density of oysters on the reefs. Of the 15 significant (and 5 marginally insignificant) correlations observed out of a total 78 examined across both studies, all but one were positive. The exception was for epifaunal invertebrate diversity vs. oyster biomass on the Rappahannock reefs. Despite these numerous positive correlations, none indicated that market-sized oysters are a prerequisite for supporting an abundant and diverse community. For example, intertidal oyster >75 mm in South Carolina typically make up <10% of all reef oysters, with a maximum of 18%. Finally, until we have a more thorough understanding of the interactions between individual species and the mechanisms linking oyster populations and reef community attributes, we propose that oyster abundance/size structure be used for assessments. Future studies need to develop and evaluate restoration progress using a combination of standardized criteria that can be applied to reef success over a wide geographical range and surrogate or indirect ecological measures (e.g., filtering, habitat use). [ABSTRACT FROM AUTHOR]

Measurements of pH drift were used to assess the ability of 38 red algal seaweeds to use bicarbonate and to deplete the dissolved inorganic carbon pool (DIC) from seawater medium. Subtidal algae were typically restricted to the use of DIC in the form of dissolved CO2, reducing the initial DIC by only 9%. Intertidal species used both dissolved CO2 and bicarbonate and reduced initial DIC by as much as 70%. DIC reductions and pH compensation points for the intertidal species tested were strongly correlated with their vertical zonation on the rocky shoreline (analysis of variance). DIC acquisition efficiency increased with tidal height, but species from the upper edge of the intertidal demonstrated a reversal of this trend. This general pattern associated with tidal height was observed not only among intertidal red algae in general, but also among four species of the genusPorphyra(P. tortaV. Krishnamurthy,P. papenfussiiKrishnamurthy,P. perforataJ. Agardh,P. fucicolaKrishnamurthy) and among four populations of the broadly distributed speciesMastocarpus papillatus(C. Agardh). TheMastocarpusobservations suggest either that individuals of this species may be able to express alternate strategies for carbon acquisition or that intertidal height may select for survivorship of genotypes with different carbon acquisition strategies. Taken together, these data suggest that the carbon acquisition strategy of intertidal red algae may be an important physiological set of adaptations that is under active evolutionary selection. These physiological differences were not related to phylogeny, tested as membership in red algal families and orders. [ABSTRACT FROM AUTHOR]