Markku Viitasalo

Effects of climate change and agricultural adaptation on nutrient loading from Finnish catchments to the Baltic Sea

Climate change is expected to increase annual and especially winter runoff, shorten the snow cover period and therefore increase both nutrient leaching from agricultural areas and natural background leaching in the Baltic Sea catchment. We estimated the effects of climate change and possible future scenarios of agricultural changes on the phosphorus and nitrogen loading to the Baltic Sea from Finnish catchments. In the agricultural scenarios we assumed that the prices of agricultural products are among the primary drivers in the adaptation to climate change, as they affect the level of fertilization and the production intensity and volume and, hence, the modeled changes in gross nutrient loading from agricultural land. Optimal adaptation may increase production while supporting appropriate use of fertilization, resulting in low nutrient balance in the fields. However, a less optimal adaptation may result in higher nutrient balance and increased leaching. The changes in nutrient loading to the Baltic Sea were predicted by taking into account the agricultural scenarios in a nutrient loading model for Finnish catchments (VEMALA), which simulates runoff, nutrient processes, leaching and transport on land, in rivers and in lakes. We thus integrated the effects of climate change in the agricultural sector, nutrient loading in fields, natural background loading, hydrology and nutrient transport and retention processes.

The mussel caging approach in assessing biological effects of wastewater treatment plant discharges in the Gulf of Finland (Baltic Sea)

Biological effects of wastewater treatment plant (WWTP) effluents were investigated in Baltic mussels (Mytilus trossulus) caged for one month 800m and 1100m from the WWTP discharge site and at a reference site 4km away. Significant antioxidant, genotoxic and lysosomal responses were observed close to the point of the WWTP discharge. Passive samplers (POCIS) attached to the cages indicated markedly higher water concentrations of various pharmaceuticals at the two most impacted sites. Modeling the dispersal of a hypothetical passive tracer compound from the WWTP discharge site revealed differing frequencies and timing of the exposure periods at different caging sites. The study demonstrated for the first time the effectiveness of the mussel caging approach in combination with passive samplers and the application of passive tracer modeling to examine the true exposure patterns at point source sites such as WWTP pipe discharges in the Baltic Sea.

Impacts of changing climate on the non-indigenous invertebrates in the northern Baltic Sea by end of the twenty-first century

Biological invasions coupled with climate change drive changes in marine biodiversity. Warming climate and changes in hydrology may either enable or hinder the spread of non-indigenous species (NIS) and little is known about how climate change modifies the richness and impacts of NIS in specific sea areas. We calculated from climate change simulations (RCO-SCOBI model) the changes in summer time conditions which northern Baltic Sea may to go through by the end of the twenty-first century, e.g., 2–5xa0°C sea surface temperature rise and even up to 1.75 unit decrease in salinity. We reviewed the temperature and salinity tolerances (i.e., physiological tolerances and occurrence ranges in the field) of pelagic and benthic NIS established in—or with dispersal potential to—the northern Baltic Sea, and assessed how climate change will likely affect them. Our findings suggest a future decrease in barnacle larvae and an increase in Ponto-Caspian cladocerans in the pelagic community. In benthos, polychaetes, gastropods and decapods may become less abundant. By contrast, dreissenid bivalves, amphipods and mysids are expected to widen their distribution and increase in abundance in the coastal areas of the northern Baltic Sea. Potential salinity decrease acts as a major driver for NIS biogeography in the northern Baltic Sea, but temperature increase and extended summer season allow higher reproduction success in bivalves, zooplankton, amphipods and mysids. Successful NIS, i.e., coastal crustacean and bivalve species, pose a risk to native biota, as many of them have already demonstrated harmful effects in the Baltic Sea.

Complex metacommunity structure for benthic invertebrates in a low-diversity coastal system

Abstract The majority of studies in metacommunity ecology have focused on systems other than marine benthic ecosystems, thereby providing an impetus to broaden the focus of metacommunity research to comprise marine systems. These systems are more open than many other systems and may thus exhibit relatively less discrete patterns in community structure across space. Metacommunity structure of soft‐sediment benthic invertebrates was examined using a fine‐grained (285 sites) data set collected during one summer across a large spatial extent (1700 km2). We applied the elements of metacommunity structure (EMS) approach, allowing multiple hypothesis of variation in community structure to be tested. We demonstrated several patterns associated with environmental variation and associated processes that could simultaneously assemble species to occur at the sites. A quasi‐Clementsian pattern was observed frequently, suggesting interdependent ecological relationships among species or similar response to an underlying environmental gradient across sites. A quasi‐nested clumped species loss pattern was also observed, which suggests nested habitat specialization. Species richness declined with depth (from 0.5 to 44.8 m). We argue that sensitive species may survive in shallower water, which are more stable with regard to oxygen conditions and present greater habitat complexity, in contrast to deeper waters, which may experience periodic disturbance due to hypoxia. Future studies should better integrate disturbance in terms of temporal dynamics and dispersal rates in the EMS approach. We highlight that shallow water sites may act as sources of recruitment to deeper water sites that are relatively more prone to periodic disturbances due to hypoxia. However, these shallow sites are not currently monitored and should be better prioritized in future conservation strategies in marine systems.

The pelagic food web

1. n nEnvironmental drivers and food web structure in the pelagic zone vary from south to north in the Baltic Sea. n n n n n2. n nWhile nitrogen is generally the limiting nutrient for primary production in the Baltic Sea, phosphorus is the limiting nutrient in the Bothnian Bay. n n n n n3. n nIn the Gulf of Bothnia the food web is to a large extent driven by terrestrial allochthonous material, while autochthonous production dominates in the other parts of the Baltic Sea. n n n n n4. n nChanges in bacterioplankton, protist and zooplankton community composition from south to north are mainly driven by salinity. n n n n n5. n nBacteria are crucial constituents of the pelagic food web (microbial loop) and in oxygen-poor and anoxic bottom waters where they mediate element transformations. n n n n n6. n nDiatoms and dinoflagellates are the major primary producers in the pelagic zone. Summer blooms of diazotrophic (nitrogen-fixing) filamentous cyanobacteria are typical of the Baltic Sea, especially in the Baltic Sea proper and the Gulf of Finland. n n n n n7. n nThe mesozooplankton (mainly copepods and cladocerans) channel energy from primary producers and the microbial food web to fish and finally to the top predators in the pelagic system (waterbirds and mammals). n n n n n8. n nHerring and sprat populations are affected by the foraging intensity of their main predator (cod), and therefore the environmental conditions that affect cod may also influence mesozooplankton due to food web effects “cascading down the food web”. n n n n n9. n nAnthropogenic pressures, such as overexploitation of fish stocks, eutrophication, climate change, introduction of non-indigenous species and contamination of top predators by hazardous substances, cause changes in the pelagic food web that may have consequences for the balance and stability of the whole ecosystem.

Environmental Impacts—Marine Ecosystems

Increase in sea surface temperature is projected to change seasonal succession and induce dominance shifts in phytoplankton in spring and promote the growth of cyanobacteria in summer. In general, climate change is projected to worsen oxygen conditions and eutrophication in the Baltic Proper and the Gulf of Finland. In the Gulf of Bothnia, the increasing freshwater discharge may increase the amount of dissolved organic carbon (DOC) in the water and hence reduce phytoplankton productivity. In winter, reduced duration and spatial extent of sea ice will cause habitat loss for ice-dwelling organisms and probably induce changes in nutrient dynamics within and under the sea ice. The projected salinity decline will probably affect the functional diversity of the benthic communities and induce geographical shifts in the distribution limits of key species such as bladder wrack and blue mussel. In the pelagic ecosystem, the decrease in salinity together with poor oxygen conditions in the deep basins will negatively influence the main Baltic Sea piscivore, cod. This has been suggested to cause cascading effects on clupeids and zooplankton.

Using remote sensing methods to identify valuable underwater habitats (Conference Presentation)

Using remote sensing methods to identify valuable underwater habitatsnnnSeagrasses are submerged plants found all over the world from brackish bays to salty continental shelves. Seagrasses create high-productive habitats and are a vital part of the marine ecosystems, providing shelter, nurseries, food, and habitats for other species. Seagrasses can be seen as indicators of environmental changes and ecosystem heath as they are sensitive to water quality. nnAccurate and detailed spatial information of seagrasses would be important in assessments of threatened habitats, establishing MPAs and evaluating ecosystem state. However, spatially comprehensive species information is usually lacking and the knowledge of seagrass habitats around the world relies on scarce field observations and models based on inventory records. Because field work is expensive and time consuming, alternative ways of acquiring information of seagrass habitats are needed. Therefore, aerial and satellite images are useful as they are provided in different resolution, times, and prices depending on the purpose of use. nnWe tested how aerial and high-resolution satellite images could be utilized in finding seagrass habitats in two different environments; in the brackish Finnish coast and in the clear tropical waters of Zanzibar, Tanzania. We did supervised classification to identify seagrasses of pre-processed aerial and satellite images. For the satellite image of the coast of Zanzibar, we also calculated water column correction. Both ways of the method worked, as the seagrass areas were found, although in the Finnish coast poor water visibility hinders light penetration below 4 meter. In developing countries, where marine inventories are usually non-existent, our methodology of utilizing low-cost images for identifying valuable habitats is the only reasonable way of acquiring marine biodiversity data.

Evaluation, gap analysis, and potential expansion of the Finnish marine protected area network

Marine Protected Areas (MPAs) are considered to be an essential tool for safeguarding marine biodiversity. Sustainable use of the oceans and seas relies on the benefits of MPAs, now even more than ever, due to environmental degradation and anthropogenic impacts on marine ecosystems. Various international and regional agreements require that nations designate sufficiently marine areas under protection. MPAs are powerful tools, if coherent and ecologically efficient. Assessing the functionality of MPA networks is challenging, unless extensive data on underwater species and habitats is available. We evaluated the efficiency of the Finnish MPA network by utilizing a unique new dataset of ~140 000 samples, collected by the Finnish Inventory Programme for the Underwater Marine Environment VELMU. For the evaluation of MPAs, we used comprehensive data on: species distribution and abundance models for over 100 taxa, IUCN Red List of Ecosystems, fish reproduction areas, EU Habitats Directive Annex I Habitats and human pressures. Using the quantitative conservation planning and spatial prioritization method Zonation, we identified sites of high biodiversity and developed a balanced ranking of underwater conservation values. Only 27 % of the ecologically most valuable features were covered by the current MPA network. Based on the analyses a set of expansion sites were identified, complementing the ecological and geographical gaps in the current MPA network. Increasing the protected sea area by just one percent with the selection of the most valuable areas indicated by the analysis, the protection level of biological features could be significantly increased. We also discovered that the EU Directive habitats are not in their present form functional proxies for marine benthic species. This suggests that MPA networks based on habitats are not sufficient for safeguarding marine biodiversity in the northern Baltic Sea. Furthermore, the produced rankings are essentially environmental value maps, they can be used in ecosystem-based marine spatial planning and impact avoidance, including, e.g., siting of wind energy or aquaculture. Our approach and analytical procedure can be replicated elsewhere in the Baltic Sea and in other marine areas around the world, provided sufficient data exists.

Information System as a Tool for Marine Spatial Planning: The SmartSea Vision and Prototype

Planning the use of marine areas requires support in allocating space to particular activities, assessing impacts and cumulative effects of activities, and generic decision making. The SmartSea project studies the Gulf of Bothnia, the northernmost arm of the Baltic Sea, as resource for sustainable growth. One objective of the project is to provide an open source and open access toolbox for marine spatial planning. Here we present a vision for the toolbox and an initial prototype. The vision is based on a model of information system as a meeting point of users, information providers, and tasks. A central technical requirement for the system was found to be a data model and related database of spatial planning and a programmable map service. An initial prototype of the system exists comprising a database, data browser/editor, dynamic tile map service, web mapping application, and extensions for a desktop GIS.