Náttúra og -tilfeingi
Impact of organic enrichment on the microbial biogeochemistry and overlying water quality in relation to fish farms in Faroese fjords.
Gunnvør á Norði
Stuðul úr Granskingargrunninum:
In fjords and other shallow areas there is a tight coupling between the seabed and the water column. Understanding the influence of anthropogenic organic load therefore requires an ecological study of the water column, the sediment and the interactions between these environments.
Natural and anthropogenic organic particles sink to the seabed where they undergo degradation by a complex web of microbial processes. The organic particles produced in the water column feed the benthic community, of both fauna and bacteria, which in turn are dependent on sedimentation rates and water conditions. In turn, the degradation of organic material results in fluxes of inorganic and organic solutes into the overlying water column. These solutes affect the living condition for farmed fish as well as natural flora and fauna.
Sea cage fish farming causes an excess load of organic material and nutrients to the adjacent environment. This excess organic material affects the seabed around the fish-farming site, and might also reduce the water quality where the fish is farmed. Bacteria feed on organic material, thus increased organic load also increases bacterial concentrations and production in the seabed but also in the water column. This might lead to lower general welfare of the farmed fish, resulting in reduced immune capacity, while fighting against natural harmless bacteria. High bacteria concentrations also reduce the water quality by using oxygen, and releasing reduced compounds to the water column.
The project will explore the following topics:
- Natural and anthropogenic input of organic material to the fjord ecosystem.
- Microbial degradation of organic material and its affect on bacterial abundance and production in the water column.
- Sedimentation rates of organic material.
- Organic enrichment onto the seabed and its impact on the microbial activity and degradation processes in sediments.
- Subsequent release of solutes from the sediment to the water column.
- Influence of water quality on feeding ratio of farmed fish.
The ultimate goal with the project is to find the maximal sustainable use of fjord systems, with emphasis on preserving the fjord ecosystem, while having a high-quality fish production.
A detailed study will be made in Kaldbaksfjørður, and the information on the fjord system can be extrapolated to other fjord systems, by investigating a few key factors in other fjords.
Gaard, E., á Norði, G., Simonsen, K. (2010) Environmental effects on phytoplankton production in a Northeast Atlantic fjord. Faroe Islands. Journal of Plankton Research 2010;doi:10.1093/plankt/fbq156 á Norði G, Glud R N, Gaard E, Simonsen K (2011) Environmental impacts of coastal fish farming: Carbon and nitrogen budgets for trout farming in Kaldbaksfjørður, Faroe Islands. Marine Ecology Progress Series (in press) á Norði, G., Simonsen, K., Gaard, E., Glud, R.N. (2010) Accumulation and mineralization of fish farming residuals in the benthic footprint area at two different farming locations in a Faroese fjord. ICES CM 2010/J:02 á Norði, G. 2010. Impact of organic enrichment on the sediment biogeochemistry and overlying water quality in relation to fish farms in Faroese fjords. PhD Thesis. NVDRit 2010:17 Oktober 2007: Sjónvarpsfyrilestur í Speki http://www.snar.fo/skipan/tilfar/fileobjects/bakteriur‐a-havbotninum/ Mars 2009: Fyrilestur í sambandi við 50 ára føðingardag og navnaskfiti hjá Havstovuni September 2010: Grein í Sjóvarmál. Februar 2011: Fyrilestur á árligu aliráðstevnuni.