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Nutrient input from estuarine producers underpins coastal fisheries production and knowing which producers are the most responsible for fish diet helps effectively protect and restore coastal ecosystems. Focussing on the Richmond River in Australia as a case study, we sampled the main estuarine producers and estimated their proportional contributions of nutritional input to seven commercially important fisheries species using Bayesian isotope mixing models. We valued the dietary input of estuarine producers to the commercial fisheries by combining dietary contribution estimates with total annual catch data from commercial fishers. A conservative estimate is that estuarine producers in the Richmond River Estuary contribute at least 82 725 kg (78%) of the total annual catch of the seven commercially important fish with an estimated annual value of $AU 450 117. Sea mullet and Mud crab contributed 95% of the total catch, and 93% of the total value assigned to estuarine producers. The two highest valued estuarine producers were tidal marsh (Juncus kraussii) $AU 82 432 and seagrass (Zostera capricorni) $AU 65 423. This study demonstrates the substantial role of estuarine producers to commercial fisheries production and the fisheries economy more broadly. With large areas of estuarine producers under threat globally from land clearing for agriculture, aquaculture and urbanisation, the results presented here provide evidence to support the value of coastal habitats and benefits of their preservation and restoration. GRAPHIC ABSTRACT: [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13280-021-01600-3.

Highlights: • Effects of microplastic on marine biota reflect the quality of experimental research. • The quality of published experiments can be quantified from an “ideal” experiment. • Previously published experiments have significantly deviated from “ideal”. • Implementation of proposed criteria can improve future microplastic experiments. Abstract: This article presents a novel conceptual blueprint for an ‘ideal’, i.e., ecologically relevant, microplastic effect study. The blueprint considers how microplastics should be characterized and applied in laboratory experiments, and how biological responses should be measured to assure unbiased data that reliably reflect the effects of microplastics on aquatic biota. This ‘ideal’ experiment, although practically unachievable, serves as a backdrop to improve specific aspects of experimental research on microplastic effects. In addition, a systematic and quantitative literature review identified and quantified departures of published experiments from the proposed ‘ideal’ design. These departures are related mainly to the experimental design of microplastic effect studies failing to mimic natural environments, and experiments with limited potential to be scaled-up to ecosystem level. To produce a valid and generalizable assessment of the effect of microplastics on biota, a quantitative meta-analysis was performed that incorporated the departure of studies from the ‘ideal’ experiment (a measure of experimental quality) and inverse variance (a measure of the study precision) as weighting coefficients. Greater weights were assigned to experiments with higher quality and/or with lower variance in the response variables. This double-weighting captures jointly the technical quality, ecological relevance and precision of estimates provided in each study. The blueprint and associated meta-analysis provide an improved baseline for the design of ecologically relevant and technically sound experiments to understand the effects of microplastics on single species, populations and, ultimately, entire ecosystems.

Marine eutrophication is a pervasive and growing threat to global sustainability. Macroalgal cultivation is a promising circular economy solution to achieve nutrient reduction and food security. However, the location of production hotspots is not well known. In this paper the production potential of macroalgae of high commercial value was predicted across the Baltic Sea region. In addition, the nutrient limitation within and adjacent to macroalgal farms was investigated to suggest optimal site-specific configuration of farms. The production potential of Saccharina latissima was largely driven by salinity and the highest production yields are expected in the westernmost Baltic Sea areas where salinity is >23. The direct and interactive effects of light availability, temperature, salinity and nutrient concentrations regulated the predicted changes in the production of Ulva intestinalis and Fucus vesiculosus. The western and southern Baltic Sea exhibited the highest farming potential for these species, with promising areas also in the eastern Baltic Sea. Macroalgal farming did not induce significant nutrient limitation. The expected spatial propagation of nutrient limitation caused by macroalgal farming was less than 100–250 m. Higher propagation distances were found in areas of low nutrient and low water exchange (e.g. offshore areas in the Baltic Proper) and smaller distances in areas of high nutrient and high water exchange (e.g. western Baltic Sea and Gulf of Riga). The generated maps provide the most sought-after input to support blue growth initiatives that foster the sustainable development of macroalgal cultivation and reduction of in situ nutrient loads in the Baltic Sea.

The Baltic Sea is a unique and sensitive brackish-water ecosystem vulnerable to damage from shipping activities. Despite high levels of maritime safety in the area, there is a continued risk of oil spills and associated harmful environmental impacts. Achieving common situational awareness between oil spill response decision makers and other actors, such as merchant vessel and Vessel Traffic Service center operators, is an important step to minimizing detrimental effects. This paper presents the Next-Generation Smart Response Web (NG-SRW), a web-based application to aid decision making concerning oil spill response. This tool aims to provide, dynamically and interactively, relevant information on oil spills. By integrating the analysis and visualization of dynamic spill features with the sensitivity of environmental elements and value of human uses, the benefits of potential response actions can be compared, helping to develop an appropriate response strategy. The oil spill process simulation enables the response authorities to judge better the complexity and dynamic behavior of the systems and processes behind the potential environmental impact assessment and thereby better control the oil combat action.

Este artículo contiene 7 páginas, 3 figuras, 1 tabla., The global distribution of primary production and consumption by humans (fisheries) is well-documented, but we have no map linking the central ecological process of consumption within food webs to temperature and other ecological drivers. Using standardized assays that span 105° of latitude on four continents, we show that rates of bait consumption by generalist predators in shallow marine ecosystems are tightly linked to both temperature and the composition of consumer assemblages. Unexpectedly, rates of consumption peaked at midlatitudes (25 to 35°) in both Northern and Southern Hemispheres across both seagrass and unvegetated sediment habitats. This pattern contrasts with terrestrial systems, where biotic interactions reportedly weaken away from the equator, but it parallels an emerging pattern of a subtropical peak in marine biodiversity. The higher consumption at midlatitudes was closely related to the type of consumers present, which explained rates of consumption better than consumer density, biomass, species diversity, or habitat. Indeed, the apparent effect of temperature on consumption was mostly driven by temperature-associated turnover in consumer community composition. Our findings reinforce the key influence of climate warming on altered species composition and highlight its implications for the functioning of Earth’s ecosystems., We acknowledge funding from the Smithsonian Institution and the Tula Foundation.

The value of critical habitats, such as seagrass, to act as a nursery varies spatially and temporally; however, such information is essential for the public and stakeholders to appropriately value and manage these habitats. We use an existing systematic long-term fisheries dataset in Port Phillip Bay to examine variability in nursery habitat value for an important commercial and recreational species, King George Whiting (Sillaginodes punctatus). Port Phillip Bay represents one of the most important marine assets in the southern hemisphere and is surrounded by the second-largest city in Australia, Melbourne, home to 4.5 million people. We modelled the abundance of King George whiting as a function of environmental variables, using Boosted Regression Trees (BRT). Fish densities ranged from 1,000 to 30,000 individuals ha−1y−1, equalling an adult biomass of 110–3,300 kg ha−1y−1. This production supports between 69 and 2,062 recreational fishing trips a year, with an estimated value of seagrass of AUD 687–20,625 ha−1y−1. Based on biomass production of King George Whiting and recreational fisheries data, the 6662 ha of seagrass in Port Phillip Bay are valued at around AUD 36 million annually.

Highlights: • We summarized 20 ecosystem services provided by coastal Baltic ecosystems. • Information on how services translate into socio-economic benefits is lacking. • The deep knowledge gap impairs the sustainable management of the benefits. • We propose a framework with four key measures to close this knowledge gap. • Toxins and Nutrients are the most well-document pressures to these services. Abstract: Seagrass meadows, algal forests and mussel beds are widely regarded as foundation species that support communities providing valuable ecosystem services in many coastal regions; however, quantitative evidence of the relationship is scarce. Using the Baltic Sea as a case study, a region of significant socio-economic importance in the northern hemisphere, we systematically synthesized the primary literature and summarized the current knowledge on ecosystem services derived from seagrass, macroalgae, and mussels (see animated video summary of the manuscript: Video abstract). We found 1740 individual ecosystem service records (ESR), 61% of which were related to macroalgae, 26% to mussel beds and 13% to seagrass meadows. The most frequently reported ecosystem services were raw material (533 ESR), habitat provision (262 ESR) and regulation of pollutants (215 ESR). Toxins (356 ESR) and nutrients (302 ESR) were the most well-documented pressures to services provided by coastal ecosystems. Next, we assessed the current state of knowledge as well as knowledge transfer of ecosystem services to policies through natural, social, human and economic dimensions, using a systematic scoring tool, the Eco-GAME matrix. We found good quantitative information about how ecosystems generated the service but almost no knowledge of how they translate into socio-economic benefits (8 out of 657 papers, 1.2%). While we are aware that research on Baltic Sea socio-economic benefits does exist, the link with ecosystems providing the service is mostly missing. To close this knowledge gap, we need a better analytical framework that is capable of directly linking existing quantitative information about ecosystem service generation with human benefit.

Summary 1.The relationship between community structure and the functioning of ecosystems is the subject of ongoing debate. Biological or functional trait-based approaches that capture life strategy, morphology and behavioural characteristics have received far less attention than taxonomic diversity in this context, despite their more intuitive link to ecosystem functioning. 2.Macrophyte primary production underpins aquatic food webs, regulates benthic and pelagic ecosystems and is a key aspect of the global carbon cycle. This study spans a range of aquatic biomes across Europe and aims to examine potential for predicting primary production of macrophyte communities based on the functional traits of species and identify the traits that are the most informative indicators of macrophyte production. 3.Macrophyte primary production was assessed based on the oxygen production of the whole community, linked to biomasses of selected biological traits derived of its component species and analysed using the novel boosted regression trees (BRT) modelling technique. 4.Results showed that functional traits derived from macrophyte community data explained most of the variation in primary production of macrophyte communities without the need to incorporate environmental data on the habitats. Macrophyte primary production was influenced by a combination of tolerance, morphology and life habit traits; however tolerance traits contributed most of variability in macrophyte primary production when all traits were analysed jointly. 5.The study also showed the existence of trait clustering as the studied trait categories were not fully independent; strong interlinkages between and within trait categories emerged. 6.Our study suggests that functional trait analysis captures different aspects of ecosystem functioning and thereby enables assessing primary production of macrophyte communities over geographically distinct areas without extensive taxonomic and environmental data. This could result in a novel framework through which a simplification of the general procedure of production estimations and comparisons across environmental gradients can be achieved. This article is protected by copyright. All rights reserved.

Aquatic invertebrate communities are influenced by interactions between the abiotic and biotic environment at multiple spatial and temporal scales. Studies of mesozooplankton community patterns in relation to spatial and temporal scales are rare. In this study, we examined scale-specific variability of mesozooplankton in the shallow coastal Baltic Sea and related this variability to key environmental proxies. Seasonality defined the majority of variability in taxonomic composition and abundance patterns, as well as in aggregated parameters of zooplankton. However, these properties also varied spatially at a large, 100-km scale. The variability in all properties except taxonomic composition was negligible at the smaller spatial scale. Taxonomic richness increased until moderate levels of total abundance, whereas peak blooms were always characterized by higher dark diversity. Shannon diversity was unrelated to total abundance. Observed spatio-temporal patterns were strongly related to abiotic forcing and uncoupled from phytoplankton standing stock and primary production. Results show the importance of seasonality over spatial variability and abiotic factors over phytoplankton variability for sub-boreal brackish coastal mesozooplankton at the spatial scales studied. Information loss from spatial generalization can be larger for taxonomic occurrences and rare species than for species abundances and aggregated community parameters such as total abundance or taxonomic richness.

Coastal ecosystems are estimated to support 95% of the world’s commercially-important fish, owing largely to their provision of nursery habitat for juveniles; however, systematic databases with such data are scarce. By systematically reviewing the literature across Australia, we quantified fisheries enhancement from three key coastal vegetated habitats: seagrass meadows, mangrove forests, and tidal marshes. From juvenile densities, we modelled adult fish biomass enhancement resulting from these structured habitats and linked fish of economic importance with market values. We found that seagrass displayed higher per hectare abundance, biomass and economic enhancement compared to mangroves and tidal marshes. On average, one hectare of seagrass supported 55,000 more fish annually compared to unvegetated seabed, resulting in an additional biomass of 4000 kg and a value increase of AUD 21,200 annually. Mangroves supported 19,000 more fish, equivalent to 265 kg−1 ha−1 y−1, and tidal marshes provided a modest 1700 more fish, equivalent to 64 kg−1 ha−1 y−1. The most abundant fish across all ecosystems were small, non-commercial species (e.g. gobies and glassfish), but the highest biomass and economic value originated from larger, longer-lived fish that are regularly targeted by fisheries (e.g. breams and mullets). By quantifying enhancement value across Australia, our findings provide further evidence for, the benefit these critical habitats provide in supporting coastal fisheries and human well-being.

The escalating spread of invasive species increases the risk of disrupting the pathways of energy flow through native ecosystems, modify the relative importance of resource (‘bottom-up’) and consumer (‘top-down’) control in food webs and thereby govern biomass production at different trophic levels. The current lack of understanding of interaction cascades triggered by non-indigenous species underscores the need for more basic exploratory research to assess the degree to which novel species regulate bottom-up and/or top down control. Novel predators are expected to produce the strongest effects by decimating consumers, and leading to the blooms of primary producers. Here we show how the arrival of the invasive crab Rhithropanopeus harrisii into the Baltic Sea – a bottom-up controlled ecosystem where no equivalent predators ever existed – appeared to trigger not only strong top-down control resulting in a decline in richness and biomass of benthic invertebrates, but also an increase in pelagic nutrients and phytoplankton biomass. Thus, the addition of a novel interaction – crab predation – to an ecosystem has a potential to reduce the relative importance of bottom-up regulation, relax benthic-pelagic coupling and reallocate large amounts of nutrients from benthic to pelagic processes, resulting in a regime shift to a degraded ecosystem state.

The North American amphipod Gammarus tigrinus is one of the most aggressive invaders recently expanding its distribution in the European waters. The species was detected in the north-eastern Baltic Sea in 2003 and has rapidly expanded its distribution ever since. This invasive amphipod has been notably successful in shallow, soft and mixed bottom habitats becoming one of the most abundant gammarid colonizing such environments. This study carried out two experiments: (1) an outdoor aquarium experiment to assess interspecific competition among the invasive G . tigrinus and the native Gammarus duebeni and compare their reproductive potential, and (2) an in situ meshbag experiment to determine the effect of adult G . tigrinus and native gammarids on juvenile gammarid amphipods. These demonstrated that the adult G . tigrinus had no effects on the adult G . duebeni ; however, the invasive amphipod had higher reproductive potential compared to the native species such as G . duebeni . Moreover, almost all adult gammarids exerted a significant predation pressure on juvenile amphipods. Thus, the combined effect of predation on juvenile amphipods and large brood production of G . tigrinus could be plausible explanations describing increased abundance of G . tigrinus and decrease of local gammarid populations in the north-eastern Baltic Sea but plausibly in similar shallow water habitats in other seas.

Knowledge and understanding of geographic distributions of species is crucial for many aspects in ecology, conservation, policy making and management. In order to reach such an understanding, it is important to know abiotic variables that impact and drive distributions of native and non-native species. We used an existing long-term macrobenthos database for species presence-absence information and biomass estimates at different environmental gradients in the northern Baltic Sea. Region specific abiotic variables (e.g. salinity, depth) were derived from previously constructed bathymetric and hydrodynamic models. Multidimensional ordination techniques were then applied to investigate potential niche space separation between all native and non-native invertebrates in the northern Baltic Sea. Such an approach allowed to obtain data rich and robust estimates of the current native and non-native species distributions and outline important abiotic parameters influencing the observed pattern. The results showed clear niche space separation between native and non-native species. Non-native species were situated in an environmental space characterized by reduced salinity, high temperatures, high proportion of soft seabed and decreased depth and wave exposure whereas native species displayed an opposite pattern. Different placement of native and non-native species along the studied environmental niche space is likely to be explained by the differences in their evolutionary history, human mediated activities and geological youth of the Baltic Sea. The results of this study can provide early warnings and effectively outline coastal areas in the northern Baltic Sea that are prone to further range expansion of non-native species as climate change is expected to significantly reduce salinity and increase temperature in wide coastal areas, both supporting the disappearance of native and appearance of non-native species.

INTRODUCTION The value of zooplankton as an indicator of ecological processes arises from its position in various food webs. Zooplankton acts as a middle point between top-down (fishes) and bottom-up (phytoplankton) regulators (Jeppesen et al., 2011). Thereby, zooplankton indirectly indicates trophic interactions between phytoplankton/bacterioplankton and zooplankton as well as zooplankton and fishes, hence, eutrophication as well as fish predation on zooplankton (Haberman, 1996). Direct predation pressure from fish can significantly impact on zooplankton communities. For example, predation-induced mortality leads to a high percentage of overall mortality in copepods (Hirst and Kiorboe, 2002; Tang et al., 2006; Martinez et al., 2014). Larger individuals of zooplankton are normally consumed in case of high rates of fish predation, which leads into a situation where domination within zooplankton communities is given to smaller individuals (Haberman, 1996; Brucet et al., 2010; Jeppesen et al., 2011). In addition to the size of zooplankton, top-down predation pressure is also affected by the morphology of various life history stages of zooplankton (Brooks and Dodson, 1965; Otto et al., 2014). A common assumption is that marine zooplankton is bottom-up controlled. Thus, it could be used as an indicator of climate change effects in the open ocean where anthropogenic impact on top of the food chain is considered to be negligible (Adrian et al., 2006; Barton et al., 2013; Daewel et al., 2014). Nevertheless, recently species on lower trophic levels have shown cascading effects in various marine ecosystems due to the overfishing of top-down predators (Casini et al., 2008, 2014). Various studies have focused on long-term dynamics of zooplankton in relation to hydro-climatic conditions in the adjacent sea (Viitasalo et al., 1995; Mollmann et al., 2000, 2008; Kotta et al., 2009). It is common in aquatic ecosystems that hierarchic response takes place along trophic levels, i.e. the intensity of response to eutrophication can vary among trophic levels (Hsieh et al., 2011; Lewandowska et al., 2014). Surprisingly, mesozooplankton has not been included into the European Water Framework Directive (WFD) as a quality element. The importance of mesozooplankton in terms of ecological environmental assessment has been demonstrated in rivers and lakes, and the necessity of including mesozooplankton in the WFD has been outlined (Jeppesen et al., 2011). However, mesozooplankton is included into the EU Marine Strategy Framework Directive (MSFD). On the basis of work carried out by the MSFD HELCOM zooplankton working group, a core indicator of food web structure based on mesozooplankton, i.e. the average size or weight of a zooplankter, was proposed by Gorokhova et al. (2013a). The indicator is also supported by total values of zooplankton abundance and biomass. Thus, the measure captures both zooplankton community structure (by mean weight) and the stock size (by biomass or abundance). In the current study we analysed the use of this indicator of good environmental status in the northeastern Gulf of Riga based on zooplankton data collected mainly from Parnu Bay. The effect of zooplankton as a food source affecting fish growth was evaluated. Seasonal and interannual variation of total abundance and biomass of zooplankton together with mean weight of a zooplankter was analysed based on both seasonal and long-term data. MATERIAL AND METHODS Field data were collected from the northeastern Gulf of Riga, mainly from Parnu Bay, between 1957 and 2013. In total 6746 quantitative samples of mesozooplankton were used (of these 3067 were collected from June to August). Zooplankton sampling and analysis followed the HELCOM recommendations (1988). Samples were collected with a Juday type plankton net (mouth opening 0.1 [m.sup.2]; mesh size 90 [micro]m) with vertical hauls from the seabed up to the surface. …