Search results for "vesiekosysteemit"
showing 10 items of 54 documents
Workshop on ICES reference points (WKREF2)
2022
The ICES Workshop on ICES reference points (WKREF2) was tasked review the WKREF1 report and based on the outcome develop updated guidelines for the ICES reference points system and recommendations for ACOM consideration. The WKREF1 report has suggested 5 key recommendations to simplify and harmonise the ICES reference points framework representing a major change to the current guidelines. At WKREF2, we detailed discussions and four key concerns were raised about the proposed approach. The first related to the simplification of rules to define Blim. Around two thirds of category 1 stocks would end up as WKREF1 “Blim Type 2” where Blim would be set as a fraction of B0. The Allee effect or “de…
Water-smart circular economy – Conceptualisation, transitional policy instruments and stakeholder perception
2022
Highlights • A concept for a water-smart Circular Economy (CE) is introduced. • Elements of a water-smart CE are presented. • Instruments to support the transition to a water-smart CE are analysed. • Drivers for and barriers to the transition to a water-smart CE are identified. The Circular Economy (CE) is a concept that has gained considerable global attention during the past decade amongst private and public sector actors, politicians and policymakers, citizens and media, and scientific communities. Water and water-related ecosystems, despite their vital role in practically all human activities, have been largely missing from conceptualisations and scientific definitions of the CE. Theref…
Bacterial Diversity in a Dynamic and Extreme Sub-Arctic Watercourse (Pasvik River, Norwegian Arctic)
2020
Microbial communities promptly respond to the environmental perturbations, especially in the Arctic and sub-Arctic systems that are highly impacted by climate change, and fluctuations in the diversity level of microbial assemblages could give insights on their expected response. 16S rRNA gene amplicon sequencing was applied to describe the bacterial community composition in water and sediment through the sub-Arctic Pasvik River. Our results showed that river water and sediment harbored distinct communities in terms of diversity and composition at genus level. The distribution of the bacterial communities was mainly affected by both salinity and temperature in sediment samples, and by oxygen…
Increasing temperature and productivity change biomass, trophic pyramids and community‐level omega‐3 fatty acid content in subarctic lake food webs
2021
Climate change in the Arctic is outpacing the global average and land-use is intensifying due to exploitation of previously inaccessible or unprofitable natural resources. A comprehensive understanding of how the joint effects of changing climate and productivity modify lake food web structure, biomass, trophic pyramid shape and abundance of physiologically essential biomolecules (omega-3 fatty acids) in the biotic community is lacking. We conducted a space-for-time study in 20 subarctic lakes spanning a climatic (+3.2 degrees C and precipitation: +30%) and chemical (dissolved organic carbon: +10 mg/L, total phosphorus: +45 mu g/L and total nitrogen: +1,000 mu g/L) gradient to test how temp…
Periphyton as a key diet source of essential fatty acids for macroinvertebrates across a nutrient and dissolved organic carbon gradient in boreal lak…
2022
We studied how physiologically important long-chain polyunsaturated fatty acids (PUFA) in benthic macroinvertebrates (Asellus aquaticus, Chironomidae, and Oligochaeta) were related to those in periphyton and terrestrial organic matter (tree leaves), collected from littoral areas of 17 boreal lakes that differed in their dissolved organic carbon (DOC) and nutrient (phosphorus and nitrogen) concentrations. We also analyzed fatty acid (FA)-specific stable carbon isotopes (δ13CFA) to investigate the dietary origin (periphyton vs. terrestrial organic matter) of PUFA in the consumers. In contrast to periphyton, terrestrial organic matter was deprived of long-chain PUFA, such as eicosapentaenoic a…
Metabolic plasticity of mixotrophic algae is key for their persistence in browning environments
2022
Light availability is the main regulator of primary production, shaping photosynthetic communities and their production of ecologically important biomolecules. In freshwater ecosystems, increasing dissolved organic carbon concentrations, commonly known as browning, leads to lower light availability and the proliferation of mixotrophic phytoplankton. Here, a mixotrophic algal species (Cryptomonas sp.) was grown under five increasing dissolved organic carbon concentrations to uncover the plastic responses behind the success of mixotrophs in browning environments and their effect in the availability of nutritionally important biomolecules. In addition to the browning treatments, phototrophic, …
Evidence of energy and nutrient transfer from invasive pink salmon (Oncorhynchus gorbuscha) spawners to juvenile Atlantic salmon (Salmo salar) and br…
2021
Recent large influxes of non‐native Pacific pink salmon (Oncorhynchus gorbuscha) to North European rivers have raised concern over their potential negative impacts on native salmonids and recipient ecosystems. The eggs and carcasses of semelparous pink salmon may provide a significant nutrient and energy subsidy to native biota, but this phenomenon has not been widely documented outside the species' native distribution. We analysed the stomach contents and stable isotope values (δ15N and δ13C) in muscle and liver tissues of juvenile Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) to determine whether these native salmonids utilise marine‐derived nutrients and energy provided by…
Benthic‐pelagic coupling and trophic relationships in northern Baltic Sea food webs
2020
Understanding marine ecosystem structure and functioning is crucial in supporting sustainable management of natural resources and monitoring the health of marine ecosystems. The current study utilized stable isotope (SI) mixing models and trophic position models to examine energy flow, trophic relationships, and benthic‐pelagic coupling between food web components. Roughly 1900 samples from different trophic levels in the food web, collected during 2001–2010 from four northern and central sub‐basins of the Baltic Sea, were analyzed for SI ratios of carbon and nitrogen. Trophic structure of the food webs among the sub‐basins was consistent, but there were differences between the proportions …
Selective Fatty Acid Retention and Turnover in the Freshwater Amphipod Pallaseopsis quadrispinosa
2021
Gammarid amphipods are a crucial link connecting primary producers with secondary consumers, but little is known about their nutritional ecology. Here we asked how starvation and subsequent feeding on different nutritional quality algae influences fatty acid retention, compound-specific isotopic carbon fractionation, and biosynthesis of omega-3 and omega-6 polyunsaturated fatty acids (PUFA) in the relict gammarid amphipod Pallaseopsis quadrispinosa. The fatty acid profiles of P. quadrispinosa closely matched with those of the dietary green algae after only seven days of refeeding, whereas fatty acid patterns of P. quadrispinosa were less consistent with those of the diatom diet. This was ma…
Community structure of macroinvertebrates, bryophytes and fish in boreal streams : patterns from local to regional scales, with conservation implicat…
2003
Voitaisiinko luonnonsuojelualueiden valinnassa käyttää nykyistä helpompia menetelmiä? Tällainen voisi olla esimerkiksi ns. ilmentäjälajien käyttö niiden valinnassa, jos eri eliöyhteisöjen rakenteet olisivat yhteneviä sekä paikallisessa että laajemmassa, esimerkiksi jokisysteemien yli ulottuvassa mittakaavassa. Riku Paavolan väitöskirjassa tarkastellaan tätä kysymystä pohjoisissa virtavesissä makroskooppisten pohjaeläinten, vesisammalten ja kalojen avulla. Aihetta on sisävesissä tutkittu maailmanlaajuisestikin erittäin vähän, eikä yhtä seikkaperäisiä nimenomaan virtavesissä tehtyjä tutkimuksia ole lainkaan olemassa. The alarming lack of information about the habitat requirements, biogeograph…