Traditional and emerging human activities are increasingly putting pressures on marine ecosystems and impacting their ability to sustain ecological and human communities. To evaluate the health status of marine ecosystems we need a science-based, integrated Ecosystem Approach, that incorporates knowledge of ecosystem function and services provided that can be used to track how management decisions change the health of marine ecosystems. Although many methods have been developed to assess the status of single components of the ecosystem, few exist for assessing multiple ecosystem components in a holistic way. To undertake such an integrative assessment, it is necessary to understand the response of marine systems to human pressures. Hence, innovative monitoring is needed to obtain data to determine the health of large marine areas, and in an holistic way. Here we review five existing methods that address both of these needs (monitoring and assessment): the Ecosystem Health Assessment Tool; a method for the Marine Strategy Framework Directive in the Bay of Biscay; the Ocean Health Index (OHI); the Marine Biodiversity Assessment Tool, and the Nested Environmental status Assessment Tool. We have highlighted their main characteristics and analyzing their commonalities and differences, in terms of: use of the Ecosystem Approach; inclusion of multiple components in the assessment; use of reference conditions; use of integrative assessments; use of a range of values to capture the status; weighting ecosystem components when integrating; determine the uncertainty; ensure spatial and temporal comparability; use of robust monitoring approaches, and address pressures and impacts. Ultimately, for any ecosystem assessment to be effective it needs to be: transparent and repeatable and, in order to inform marine management, the results should be easy to communicate to wide audiences, including scientists, managers, and policymakers.

No abstract

As the EU's commitment to renewable energy is projected to grow to 20% of energy generation by 2020, the use of marine renewable energy from wind, wave and tidal resources is increasing. This literature review (233 studies) (i) summarizes knowledge on how marine renewable energy devices affect benthic environments, (ii) explains how these effects could alter ecosystem processes that support major ecosystem services and (iii) provides an approach to determine urgent research needs. Conceptual diagrams were set up to structure hypothesized cause-effect relationships (i.e. paths). Paths were scored for (i) temporal and spatial scale of the effect, (ii) benthic sensitivity to these effects, (iii) the effect consistency and iv) scoring confidence, and consecutively ranked. This approach identified prominent knowledge gaps and research needs about (a) hydrodynamic changes possibly resulting in altered primary production with potential consequences for filter feeders, (b) the introduction and range expansion of non-native species (through stepping stone effects) and, (c) noise and vibration effects on benthic organisms. Our results further provide evidence that benthic sensitivity to offshore renewable effects is higher than previously indicated. Knowledge on changes of ecological functioning through cascading effects is limited and requires distinct hypothesis-driven research combined with integrative ecological modelling.

No abstract

The eutrophication status of the entire Baltic Sea is classified using a multi-metric indicatorbased assessment tool. A total of 189 areas are assessed using indicators where information on reference conditions (RefCon), and acceptable deviation (AcDev) from reference condition could be combined with national monitoring data from the

Followed by the massive increase in the biomass of Pilayella littoralis, Fucus vesiculosus has almost disappeared in Kõiguste Bay, north-eastern Baltic Sea during 1995 -1998. Consequently, Idotea baltica, which previously fed on Fucus, switched to new food items -Furcellaria lumbricalis and Pilayella littoralis. Idotea grazed more Pilayella than Furcellaria whereas Furcellaria was highly preferred as a habitat. Maximum 2.2% and 4.7% of the production of Furcellaria and Pilayella were removed by grazing. We conclude that the grazing pressure by Idotea is not sufficient to control the outbreak of Pilayella. However, Idotea has an advantageous effect on the persistence of Furcellaria by preferentially removing fast growing epiphyte Pilayella.

No abstract

Studies on the effects of increasing acidification on marine communities have been previously mostly carried out in truly marine areas whereas brackish-water ecosystems such as the Baltic Sea have been less studied. The current study analyses how acidification induced by elevated atmospheric carbon dioxide affects the photosynthetic net production of different macroalgal species in the brackish Baltic Sea. Research methods include sets of laboratory and field experiments carried out in shallow coastal brackish waters. The aim of the laboratory experiments was to develop the necessary techniques and experience for the mesocosm experiments. Laboratory experiments were carried out using specimens of the red alga Furcellaria lumbricalis collected from Kakumäe Bay. The mesocosm experiments were conducted in Kôiguste Bay during the field season of 2011. Separate mesocosms were operated in each set with different CO2 concentrations and a control treatment in natural conditions. Field experiments were carried out with three species representing three different morphological and ecological groups: Ulva intestinalis, a fast-growing green alga; Fucus vesiculosus, a perennial brown alga with a slow metabolism; and Furcellaria lumbricalis, a perermial red alga. Photosynthetic activity was used as the response variable. In the laboratory decreasing pH increased the net primary production of F. lumbricalis with the lowest net primary production values measured at pH 8.0 and the highest at pH 6.5. Results of the field experiments indicated that increased CO? levels in seawater favoured photosynthetic activity of the macroalgae U. intestinalis and F. lumbricalis, but F. vesiculosus showed no response to elevated CO2. Elevated CO2 levels are suggested to favour the production of fast-growing filamentous species, which thus may indirectly enhance the effect of eutrophication in the shallow coastal brackish waters.