| 1. |
- Bergström, Lena, et al.
(författare)
-
The effects of wind power on marine life : A Synthesis
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- As in many other countries, an expansion of wind power is expected in Sweden during the coming decades. The expansion is driven by rising prices on electricity and the need for an increased production of renewable energy. Since wind conditions at sea are good and relatively constant, several offshore wind farms are planned in Swedish waters. Offshore wind power with a total effect of about 2500 MW has been granted permission and an additional 5500 MW are being planned for. Examples of granted projects are Storgrundet with an effect of 265 MW, Stora Middelgrund with an effect of 860 MW and Kårehamn with an effect of 48 MW. The largest offshore wind farm in Sweden today is Lillgrund in Öresund, with its 48 turbines with an installed effect of 110 MW.Prior to this expected expansion, it is important to investigate the environmental impact of offshore wind power, and how possible negative effects can be minimized. This synopsis about the impact of wind power on the marine life in Swedish waters is based on more than 600 studies, most of which are scientific articles, but also reports by companies and authorities.Habitats and species in Swedish marine areasSwedish marine areas are characterized by a unique salinity gradient that varies from marine conditions in Skagerrak to almost limnic environments in the Gulf of Bothnia. There are also vast differences between areas in terms of environmental factors such as insolation, temperature and wave exposure. This entails variation in species composition, dominance by different populations and structural differences in plant and animal communities. Therefore, this synopsis provides environment descriptions of three widely separated marine areas: the Swedish West Coast (Kattegat and Skagerrak), the Baltic Proper and the Gulf of Bothnia (Bothnian Sea and Bothnian Bay). The main focus is on occurrence of species and communities within the depth interval that is of interest for establishing offshore wind power in Sweden.Offshore wind powerThere are mainly two types of foundation structures used in Sweden today: gravity-based foundations and monopile foundations. These are also the most commercially viable. Offshore wind farm projects affect the environment in different ways during installation, operation and decommissioning. The installation phase is assessed as having the largest impact on the environment, since high noise levels and sediment dispersal can affect marine organisms. A wind farm during operation can cause barrier effects as well as changes in the natural environment. The decommissioning phase can again enhance noise levels and lead to sediment dispersal in the wind park and its adjacent area. Effects on marine organisms and communities Since marine environmental conditions vary between different locations as well as over time, it is difficult to make universal assessments of the effects of offshore wind power. This increases the importance of well-designed pilot studies and monitoring programs of the local environment. Also, location-specific surveys minimize the risk that costly measures to reduce negative impact are used when they are not needed. In general, installation and decommissioning of offshore wind farms should be planned so that sensitive reproductive periods for marine species are avoided. Particular consideration might also be needed for constructions in important growth and spawning areas for fish and marine mammals, or specific environments, such as offshore banks with high natural values. Below is a list of the effects that, according to existing knowledge and accessible literature, might affect marine organisms and communities. Each effect has been assessed after how long, and to what scale, it affects the marine life in the wind farm area.Acoustic disturbances during the installationAs monopile foundations are being driven into the sea floor, a lot of noise is generated that spreads in the water. Cod and herring can potentially perceive noise from pile driving at a distance of 80 kilometres, experiencing physical damage and death at just a few meters from the place of installation. For all types of work involving noise, flight reactions in fish are expected within a distance of about one kilometre from the source. The greatest risk of significant harm to fish populations exists if the installation overlaps with important recruitment areas for threatened or weak populations. Among the marine mammals, porpoises have proved to get both impaired hearing and behavioural disturbances from noise associated with pile driving. There are no studies indicating any long-term negative effects on any of the seal species occurring in Swedish waters. It is not possible to draw any general conclusions of the effects on invertebrates from pile driving noise, since the group is too large and diverse. The few studies that exist, however, show that oysters are relatively sensitive, whilst mussels are not affected at all. The effects of high noise levels can be reduced by, for example, successively increasing the power and thus the noise during piling, so that larger animals such as fish, seal and porpoises are intimidated at an early stage and leave the construction area well before high noise levels are reached.Sediment dispersalDredging work during the construction of gravitational foundations, and laying of cables between the wind turbines and land, can cause sediment from the bottom to whirl up and disperse in the water mass. The amount of sediment dispersed depends on the type of sediment, water currents and which dredging method is being used. Increased concentrations of sediment in the water affect mainly fish fry and larval stages negatively. Invertebrates are often adapted to re-suspension of sediment, since it occurs naturally in their environment. The sediment dispersal at the construction of a wind farm is often confined to a short period. The effects are also relatively small due to the fact that the bottom sediment is usually coarse-grained. The overall assessment is therefore that sediment dispersal is a limited problem for most animal and plant communities, but specific consideration should be taken and fish recruitment periods should be avoided.Introduction of a new habitatThe foundations of wind turbines can function as artificial reefs and attract many fish species, particularly around gravitational foundations which have a structurally complex erosion protection. At first there is often a redistribution of fish from nearby areas to the wind park foundations, but over time an actual increased fish production within the park is possible, as long as the park is large enough and the fishing pressure is low. The structure of the erosion protection can bring local positive effects for crustaceans such as lobster and crab, by functioning as shelter as well as increasing their foraging area. One example of a species that seems to increase locally around foundation structures on the Swedish West Coast and the Baltic Proper is the blue mussel. Which species that will dominate depends on the salinity in the area. There are no studies showing that foundation structures will facilitate the distribution of new species to Swedish marine areas. One reason for this might be that the total amount of hard bottom surface formed by the foundations and their structures is relatively small compared to natural hard bottoms.Turbine noise and boat trafficMaintenance work on the wind turbines causes a certain increase in boat traffic in the area of an operating wind farm. Also, different parts of the turbines generate noise during operation that spreads through the water. The reactions of fish on noise from turbines and boat engines vary, but study results indicate that the effect on most fish species from noise produced in a wind farm is low. There are, however, no studies on long-term effects of stress due to an increased noise level or effects of noise disturbance on fish spawning behaviour. Porpoises especially, but to some extent also seals, are sensitive to noise disturbance. Today there are no studies showing negative effects from the operational sounds from a wind farm on populations of marine mammals. The noise of both strong winds and engines from ships often exceeds the underwater noise generated by operating wind farms.Electromagnetic fieldsThe electric cables leading from a wind turbine generates a magnetic field that decreases with distance from the cable. The expected effect on most fish species is low, but since the effect is ongoing throughout the entire operational stage, the risk should be considered in areas that are important to migrating fish species. No studies have been found that show how electromagnetic fields affect marine mammals. The few studies that have been found on invertebrates indicate that the electromagnetic fields around common transmission cables have no effect on either reproduction or survival.Exclusion of birdsMost birds do not avoid wind farm areas. An exception is several common diving ducks that avoid flying or swimming within wind farms and keep a safe distance of at least 500 meters to a turbine tower. The most common food for these species in the Baltic Sea is blue mussels. Areas within the Swedish economic zone where a large-scale expansion of wind power would have the greatest effect on the ducks, and thereby indirectly affect the benthic community, are the offshore banks in the central Baltic Proper, mainly Hoburg Bank and Northern Midsjö Bank, where two thirds of the oldsquaw populations in Europe overwinters. The level of impact will depend on the total area of the park, and the distance between the turbine towers. Large-scale studies are needed in order to assess if the effect might lead to substantial changes for the benthic community.Gaps of knowledgeThe basis of this synopsis is research results from studies concerning single wind turbines or small wind farms, which in many
|
|
| 2. |
- Bergström, Lena, et al.
(författare)
-
Vindkraftens effekter på marint liv : En syntesrapport
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Precis som i manga andra lander forvantas en utbyggnad av vindkraft i Sverige under de narmaste decennierna. Expansionen drivs bland annat av stigande elpriser och behovet av okad produktion av fornybar el. I Sverige har havsbaserad vindkraft med en total effekt pa ungefar 2500 MW fatt tillstand och ytterligare 5500 MW ar under utveckling. Exempel pa vindkraftsprojekt med fardiga tillstand ar Storgrundet med en effekt pa 265 MW, Stora Middelgrund med en effekt pa 860 MW och Karehamn med en effekt pa 48 MW. I dag utgor Lillgrund i Oresund med sina 48 vindkraftverk och 110 MW i installerad effekt, Sveriges storstahavsbaserade vindkraftpark. Infor denna forvantade expansion ar det viktigt att undersoka vindkraftens miljoeffekter, och hur eventuella negativa effekter kan minimeras. Over 600 studier, huvudsakligen vetenskapliga artiklar, men aven rapporter fran foretag och myndigheter, ligger till grund for slutsatserna och rekommendationerna i denna syntesrapport om paverkan av vindkraft pa det marina livet i svenska havsomraden. [...]
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Greger, Maria, et al.
(författare)
-
Heavy metal transfer from composted macroalgae to crops
- 2007
-
Ingår i: European Journal of Agronomy. - : Elsevier BV. - 1161-0301 .- 1873-7331. ; 26:3, s. 257-265
-
Tidskriftsartikel (refereegranskat)abstract
- Marine macroalgal compost may be used as fertiliser in agriculture and horticulture. However, macroalgae may accumulate heavy metals, thereby rendering compost made from it unsuitable for food crop production. Our aim was to determine whether the edible parts of crop plants grown in various macroalgal composts contain elevated concentrations of heavy metals. Compost of seaweed beach-cast containing up to 85% red macroalgae and experimentally produced red and brown-algal (Fucus serratus) composts, respectively, were used in cultivating vegetables. The vegetables produced were compared with ones cultivated in composted horse manure and in soil in terms of transfer of cadmium (Cd), and in some cases also of copper (Cu), lead (Pb), and mercury (Hg) from the different substrates to the edible parts of the plants. Effects of the composted material on biomass production and seed germination were also examined. Concentrations of Cu, Hg, and Pb were not elevated in either of the composts or in the crop plants compared with limit values for cultivated plants and soil. However, the concentration of Cd in the composts and crop plants was greater than the limit values for arable soil and cultivated plants, respectively. Furthermore, more Cd was transferred to the plants grown in red-algal than in brown-algal (F. serratus) compost, despite the fact that the brown-algal (F. serratus) compost had a higher Cd concentration. The Cd concentrations in lettuce and oats cultivated in the seaweed composts exceeded official EU limit values, while the concentrations in root vegetables and leguminous plants were lower than the limit values. Cultivation in composted red macroalgae increased the biomass production of all vegetables except beans, compared with cultivation in the other substrates. However, the germination frequency was lower for seed sown in composted red and brown algae than for seed sown in soil. We conclude that although cultivation of food crops directly in composted macroalgae (specifically, composted red algae) would enhance yields, it is not recommended. Instead, macroalgal compost could be used in smaller amounts on agricultural soils as a valuable nutrient source for non-food crop cultivation.
|
|
| 7. |
- Malm, Torleif, et al.
(författare)
-
Bentiska processer på och runt artificiella strukturer i Sveriges kustvatten
- 2011
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Inom de närmaste decennierna kommer sannolikt vindkraftsparker med en utbredning på många kvadratkilometer att byggas i svenska kustvatten. Dessa installationer kan påverka miljön med dess ekologiska samhällen på olika sätt; till exempel genom den redan kända reveffekten, genom att populationsstrukturen hos viktiga predatorer som fisk och mussel- och fiskätande fåglar kan förändras, eller genom förändrade strömmar som kan gynna vissa arter, främst mjukbottenarter, medan andra arter missgynnas. Därigenom kan trofiska kaskader (födovävsinteraktioner) ner i det bentiska samhället uppstå på såväl hård- som mjukbottnar. Hur parkerna påverkar de ekologiska samhällena beror troligen i hög grad på de initiala förhållandena i de aktuella områdena. Under perioden 2005–2009 utfördes en studie i syfte att undersöka den bentiska samhällsstrukturen på hårdbottnar före och efter byggnationen av större vindkraftparker. De områden som undersöktes var, Skottarevet i Kattegatt, Lillgrund i södra Öresund, Utgrunden II i södra Kalmarsund, Kårehamn utanför nordöstra Öland samt Klasådern utanför sydvästra Gotland. Av legala och ekonomiska orsaker byggdes endast en park, Lillgrund, under projekttiden. Vi fann betydande samhällsskillnader mellan områdena på såväl art- som funktionell nivå. Den största skillnaden fann vi mellan Kattegatt och Östersjön med stora skillnader i artsammansättningen och delvis med andra funktionella grupper. Även inom Östersjölokalerna hittades betydande skillnader. Samhällena i de båda sunden hade betydligt högre biomassor av musslor per kvadratmeter än de öppna områdena vid Gotland och Öland. Även algfloran skilde sig betydligt. I sunden dominerade övergödningsgynnade fintrådiga brunalger medan bottnarna längs de öppna kusterna i högre grad var beklädda med perenna rödalger. Vindkraftsutbyggnaden vid Lillgrund påverkade de bentiska samhällena måttligt men tydligt. Musslor och havstulpaner koloniserade fundament och erosionsskydd snabbt. Redan efter två år hade de artificiella och naturliga substraten en liknande samhällsstruktur. Dessutom verkar bottnarna som helhet ha påverkats av parken. Jämfört med tidigare år hade de naturliga substraten år 2009 en större biomassa av musslor och havstulpaner och en lägre biomassa av fintrådiga alger. Skillnaden var liten men signifikant.Slutsatsen av denna studie är att vindkraftsparker möjligen kan ge ekologiska effekter på bottensamhällena men att vår studie har sådana brister i geografisk och tidsmässig utsträckning att det inte säkert går att dra denna slutsats. Eftersom förhållandena runt våra kuster skiljer sig åt kan man inte dra säkra slutsatser från en plats. Det är också svårt att dra slutsatser från den korta period som förflutit sedan byggnationen av parken. Meteorologiska och oceanografiska processer som inte är relaterade till vindkraftsparken kan ha bidragit till resultatet.
|
|
| 8. |
|
|
| 9. |
- Malm, Torleif, et al.
(författare)
-
Grazing effects of two freshwater snails on juvenile Fucus vesiculosus in the Baltic Sea
- 1999
-
Ingår i: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 188, s. 63-71
-
Tidskriftsartikel (refereegranskat)abstract
- The low salinity in the non-tidal Baltic Sea excludes many species, including marine littorinoids. The only large gastropods that occur in substantial quantities in the central Baltic proper are the freshwater snails Lymnaea peregra (O.F. Müller) and Theodoxus fluviatilis (L.); both are known to consume filamentous green and brown algae. The main objective of the present study was to test the hypothesis that freshwater snails can exert substantial grazing pressure on juvenile and regenerating Fucus vesiculosus populations in the Baltic Sea. In laboratory experiments, both snail species were able to graze on F. vesiculosus germlings up to a size of approximately 0.8 to 1.0 mm. During the study period (autumn 1996 and spring and summer 1997), the largest F. vesiculosus germlings of the cohorts settled in September and May reached approximately 1.0 mm at the same time (July). Thus, to reach the 'safe' size and escape grazing requires about 8 mo for germlings settling in autumn but only 1 mo for germlings settling in spring. The survival and growth rate of new fronds from regenerating F. vesiculosus holdfasts in outdoor tank experiments were higher than for sexually recruited juveniles. After 1 yr, 95% of the holdfasts had survived, and the mean length (±SE) of the largest frond on each holdfast was 12 ± 2 mm. Grazing by L. peregra or T. fluviatilis did not affect regeneration or frond growth. During a long-term field study (1991 to 1994), an average of 8.5 ± 0.7 T. fluviatilis ind. dm-2 were found, with a maximum density of 40 ind. dm-2 in September. During a 1 yr study (1996), the average density of L. peregra was comparatively low and varied from 0.5 ind. dm-2 in April to 20 ind. dm-2 in August. The higher density found in August (L. peregra) and in September (T. fluviatilis) suggests that both species may have a grazing impact during this time. We conclude that both T. fluviatilis and L. peregra have the capacity to graze on zygotes and germlings of F. vesiculosus until they reach a safe size of approximately 0.8 to 1.0 mm. Both snail species can occasionally reach abundances high enough to affect the recruitment of F. vesiculosus. Freshwater snails do not affect the regeneration from holdfasts. However, because the time for germlings settled in autumn to reach a safe size is much longer than for germlings settled in spring, it is possible that even a low snail density has an impact on recruitment in the field. This will, however, require verification because levels of grazing activity during different times of the year are unknown.
|
|
| 10. |
- Malm, Torleif
(författare)
-
Hårt substrat i marin miljö : En litteraturöversikt
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport sammanfattar den litteratur som diskuterar hårda substrats betydelse för de bottenlevande samhällena. Marina vindkraftverk uppförs för närvarande i tusental längs västra och norra Europas kuster. Det väcker berättigade frågor om vilka effekter detta kan ha på den marina miljön. Den så kallade reveffekten har i sammanhanget blivit mycket uppmärksammad. Med detta begrepp avses en lokal ansamling av fisk, ryggradslösa djur och alger på och runt fundamenten och deras erosionsskydd. Det är dock ur strikt vetenskaplig synvinkel felaktigt att tala om reveffekten som positiv eller negativ som sådan. Om reveffekten ger en lokal ökning av den biologiska mångfalden i artfattiga men unika habitat kan den vara negativ men om den skyddar hotade arter, exempelvis hårt beskattade bestånd av fisk och skaldjur är den positiv. En artificiell struktur kan också vara en inkörsport för nya främmande arter som kan påverka samhällen och system över stora områden. Effekten av en artificiell struktur som ett vindkraftsfundament bör därför bedömas från fall till fall utifrån de miljöförhållanden som råder på platsen. Vindkraftverkens fundament består av betong eller stål och betong och de kan olika lutning och orientering. Substratets egenskaper kan ha betydelse för larvers och sporers chans att hitta en lämplig plats att sätta sig fast och överleva. Störst betydelse verkar substratet ha vid primär succession, det vill säga när en större yta nykoloniseras efter en störning. Larver och sporer sprids med vågor och strömmar. I det tunna gränslagret mot klippan där vattenrörelserna är små kan förmågan att simma ha betydelse för valet att etableringsplats. Särskilt larver söker sig till gropar i storleksordningen 1–10 millimeter. Algsporer som ofta saknar simförmåga kan i stället reglera sin klibbighet och avvägning och på det viset hitta lämpliga miljöer att etablera sig i. Även algsporer föredrar en räfflad struktur men den optimala reliefen beror på den enskilda arten och storleken på dess sporer. Överlevnaden hos vuxna organismer kan påverkas av klippas topografi. Vågkrafterna är ofta svagare i sprickor och detta gynnar överlevnaden av både fastsittande djur, fleråriga stora alger och betare. Substratets lutning har stor betydelse för vilket samhälle som etableras. Vågornas kraft är större på en vertikal jämfört med en horisontal yta och de olika organismerna växer därför djupare på en vertikal yta jämför med en horisontal. Vertikala ytor är oftast djurdominerade medan alger förhärskar på horisontala ytor. På stenrev är störningsfrekvensen stor. Under stormar välts och snurrar blocken vilket framförallt påverkar stora och fleråriga organismer negativt. Den biologiska mångfalden är störst på medelstora block. På små block hinner bara efemära arter etablera sig mellan störningstillfällena medan störningsfrekvensen på de största blocken är låg och samhällena där liknar den fasta klippan som domineras av konkurrenskraftiga, fleråriga arter. Klippans mineralsammansättning verkar ha liten betydelse för etableringen av alger och djur i marin miljö. Biofilmen av mikroorganismer som alltid etableras före de makroskopiska organismerna tycks utjämna skillnader mellan substrat olika kemisk sammansättning. Mineralsammansättningens betydelse för verlevnaden av vuxna organismer är också dåligt utforskad. Borrande organismer, organismer som etsar substratet med kemikalier eller penetrerar berget med rizoider tycks vara mer framgångsrika på kalkberggrund jämför med en sur berggrund som granit. Substratets färg har betydelse för etableringen av vissa djur men responsen varierar mycket mellan olika arter.
|
|
