Mixing apples and oranges: Assessing ecological status and its confidence from multiple and diverse indicators

Ecosystem responses to increasing human pressures are complex and diverse, affecting organisms across all trophic levels. This has prompted the development of methods that integrate information across many indicators for environmental management. Legislative frameworks such as the European Water Framework Directive (WFD), specifically prescribe that integrated assessme nt (IA) of ecological status must consider indicators representing various biological and supporting quality elements. We present a general approach for an IA system based on a piece-wise linear transformation of indicator distributions to a standardized scale, allowing for integrating information from multiple and diverse indicators through a policy-dependent aggregation scheme. Uncertainties associated with monitoring data used for calculating indicators and their propagation throughout the integration scheme allow for confidence assessment at all levels of the hierarchical integration. Specific pressures leading to ecological impact can be identified through the most impaired indicators in the hierarchical and transparent aggregation scheme. The IA and its confidence are facilitated though the development of an online tool that accesses information from monitoring databases and presents the outcome at all levels of the assessment, ensuring consistency and transparency in the calculations for all potential stakeholders. We demonstrate the versality and applicability of the approach using indicators and aggregation principles from the Swedish national guidelines for assessing ecological status of rivers, lakes and coastal waters according to the WFD. Although the approach and the tool were developed specifically for the WFD ecological status assessment in Sweden, the generality of the approach implies that it can easily be adapted to the WFD assessment methods of other countries as well as other policies, where an integrated assessment is required.publishedVersio

Physical and numerical modeling of the role of hydrodynamic processes on adult-larval interactions of a suspension-feeding bivalve

The importance of hydrodynamic processes for adult-larval interactions in the cockle, Cerastoderma edule, was examined through physical and numerical modeling. A set of physical experiments in a flow-tank using adult cockles and larval mimics showed that the settlement of particles was affected by adult cockles. Settlement was reduced by 20% in an area of 2.5 cm2 surrounding the siphons, and the most marked decrease occurred near the inhalant siphon. On a larger spatial scale downstream of the siphons, settlement was more heterogeneous compared to surfaces without cockles. The experimental results near individual cockles were compared with numerical models of settlement dynamics in conditions with no horizontal flow. The models suggest that the vertical position of the siphon orifice determines whether any small-scale reduction in larval settlement should be expected near suspension-feeding benthic invertebrates. The results are compared qualitatively and quantitatively with previous observations of small-scale patterns (≈1 cm) around individual C. edule and with observations of larger-scale (1-10 m) differences among patches with varying densities of cockles. These comparisons indicate that passive hydrodynamic processes can explain patterns around individual cockles, whereas a combination of active and passive processes are necessary to explain differences among patches. Such hydrodynamic modification of larval behavior has previously been reported to greatly increase rates of mortality for settling bivalve larvae

Seabed Mapping and Marine Spatial Planning: A Case Study from a Swedish Marine Protected Area

Physical chemistr

Chapter Seabed Mapping and Marine Spatial Planning: A Case Study from a Swedish Marine Protected Area

Physical chemistr

The invasive Pacific oyster, Crassostrea gigas, in Scandinavia coastal waters:A risk assessment on the impact in different habitats and climate conditions

A massive invasion of the Pacific oyster, Crassostrea gigas, has occurred in Scandinavia during the last decade. The introduction and dispersal was described through collaboration between scientists from Sweden, Denmark and Norway. This work has been followed up by national activities that clearly visualized the need for a continued collaboration between scientists in the Scandinavian countries, as the bio-invasion is a cross-border issue and management actions then have to be synchronized, and based on a “state of the art” knowledge of the Scandinavian bio-invasion of the species. The risk assessment presented in this report is based on available scientific literature, expert judgments and data collected during a Nordic collaboration project on Pacific oysters in 2011 – 2013

Testing the Potential for Predictive Modeling and Mapping and Extending Its Use as a Tool for Evaluating Management Scenarios and Economic Valuation in the Baltic Sea (PREHAB)

Peer reviewe

Impact of an icy winter on the Pacific oyster (Crassostrea gigas Thunberg, 1793) populations in Scandinavia

The Pacific oyster (Crassostrea gigas) is an invasive species that has dispersed into Scandinavia during the last few decades. The objective of this study was to evaluate the effects of extreme winter conditions on the mortality of the Pacific oyster in Scandinavia. The study was done by compiling mortality data from independent surveys in Denmark, Sweden and Norway. Winter mortality of the oysters increased with latitude, which can be explained by the colder climate experienced at higher latitudes. Mortality was also found to be affected by site specific conditions such as water depth at the sampling sites of oyster populations. Despite the severe winter conditions of 2009/2010 causing high mortality, the Pacific oyster still exists in large numbers in Scandinavia. The present investigation indicates that extreme winter onditions may result in a temporary reduction of the density of the Pacific oyster, but that the species can be expected to continue its invasion of Scandinavian coastal areas.publishedVersio

Cleaning up seas using blue growth initiatives : Mussel farming for eutrophication control in the Baltic Sea

Eutrophication is a serious threat to aquatic ecosystems globally with pronounced negative effects in the Baltic and other semi-enclosed estuaries and regional seas, where algal growth associated with excess nutrients causes widespread oxygen free “dead zones” and other threats to sustainability. Decades of policy initiatives to reduce external (land-based and atmospheric) nutrient loads have so far failed to control Baltic Sea eutrophication, which is compounded by significant internal release of legacy phosphorus (P) and biological nitrogen (N) fixation. Farming and harvesting of the native mussel species (Mytilus edulis/trossulus) is a promising internal measure for eutrophication control in the brackish Baltic Sea. Mussels from the more saline outer Baltic had higher N and P content than those from either the inner or central Baltic. Despite their relatively low nutrient content, harvesting farmed mussels from the central Baltic can be a cost-effective complement to land-based measures needed to reach eutrophication status targets and is an important contributor to circularity. Cost effectiveness of nutrient removal is more dependent on farm type than mussel nutrient content, suggesting the need for additional development of farm technology. Furthermore, current regulations are not sufficiently conducive to implementation of internal measures, and may constitute a bottleneck for reaching eutrophication status targets in the Baltic Sea and elsewhere. Highlights • Mussel farming is a viable internal measure to address Baltic Sea eutrophication. • Rates of nutrient removal depend on salinity at the regional scale and food availability at the local scale. • Cost effectiveness of nutrient removal by mussel farming depends also on farm type. • Total farm area needed for achieving HELCOM nutrient reduction targets is realistic