Search results for "vesiekosysteemit"
showing 4 items of 54 documents
Improving statistical classification methods and ecological status assessment for river macroinvertebrates
2016
Aquatic ecosystems are facing a growing number of human-induced stressors and the need to implement more biomonitoring to assess the ecological status of water bodies is eminent. This dissertation aims at providing tools to reduce the costs and improve the accuracy of freshwater benthic macroinvertebrate biomonitoring. To improve the cost-e ciency, we consider automated classi cation and develop a novel classi er suitable for complex macroinvertebrate image data. To enhance the accuracy of macroinvertebrate biomonitoring, we study the statistical properties of the Percent Model A nity index crucial to current Finnish biomonitoring and the factors a ecting these statistics. Finally, we perfo…
Hydrogen isotopes (δ2H) of polyunsaturated fatty acids track bioconversion by zooplankton
2022
1. Organisms at the base of aquatic food webs synthesize essential nutrients, such as omega-3 polyunsaturated fatty acids (n-3 PUFA), which are transferred to consumers at higher trophic levels. Many consumers, requiring n-3 long-chain (LC) PUFA, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have limited ability to biosynthesize them from the essential dietary precursor α-linolenic acid (ALA) and thus rely on dietary provision of LC-PUFA. 2. We investigated LC-PUFA metabolism in freshwater zooplankton using stable hydrogen isotopes (δ2H) of fatty acids as tracers. We conducted feeding experiments with the freshwater keystone grazer Daphnia to quantify changes in the δ2…
Effects of organic material on the bioavailability, toxicokinetics and toxicity of xenobiotics in freshwater organisms
2001
Pohjoisille ekosysteemeille tyypillinen runsas orgaanisen aineksen määrä joko liuenneena vedessä tai järvien pohjamudassa voi sitoa useita kemiallisia saasteita ja siten vähentää eliöiden altistumista niille sekä siitä syntyviä myös koko ekosysteemille haitallisia vaikutuksia. Anna Nikkilän tutkimuksessa havaittiin, että orgaaninen aines voi vähentää merkittävästi harvasukamadon sekä vesikirpun altistumista tietyille rasvaliukoisille ympäristömyrkyille aromaattisten monirenkaisten hiilivetyjen (pyreeni, reteeni) sekä kloorifenolien (2,4,5-trikloorifenoli, pentakloorifenoli) ryhmistä. Osa tutkituista yhdisteistä sitoutui orgaaniseen ainekseen eikä näin ollut eliöille altistavassa muodossa. V…
Assessing the conservation priority of freshwater lake sites based on taxonomic, functional and environmental uniqueness
2022
Aim We propose a novel approach that considers taxonomic uniqueness, functional uniqueness and environmental uniqueness and show how it can be used in guiding conservation planning. We illustrate the approach using data for lake biota and environment. Location Lake Puruvesi, Finland. Methods We sampled macrophytes and macroinvertebrates from the same 18 littoral sites. By adapting the original “ecological uniqueness” approach, we used distance-based methods to calculate measures of taxonomic (LCBD–t), functional (LCBD–f) and environmental (LCEH) uniqueness for each site. We also considered the numbers and locations of the sites needed to protect up to 70% of total variation in taxonomic, fu…