Search results for "vesieläimistö"

Community size can affect the signals of ecological drift and niche selection on biodiversity

2020

Made available in DSpace on 2020-12-12T01:24:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Academy of Finland Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Ecological drift can override the effects of deterministic niche selection on small populations and drive the assembly of some ecological communities. We tested this hypothesis with a unique data set sampled identically in 200 streams in two regions (tropical Brazil and boreal Finland) that differ in macroinvertebrate community size by fivefold. Null models allowed us t…

Ecological niche features override biological traits and taxonomic relatedness as predictors of occupancy and abundance in lake littoral macroinverte…

2018

The degree to which species ecological and biological traits determine their distribution and abundance has intrigued ecologists for a long time, and it has seen a revival in recent years. This topic is important because it provides information about the determinants of species rarity and their conservation implications. We examined the effects of niche breadth, niche position, biological traits and taxonomic relatedness on the interspecific occupancy–abundance relationship, as well as on occupancy and abundance, in lake littoral macroinvertebrates. We sampled 48 lakes in a boreal lake district, found altogether 155 species, and calculated regional occupancy (as the proportion of sites occu…

Sulfate sensitivity of aquatic organism in soft freshwaters explored by toxicity tests and species sensitivity distribution

2023

Elevated concentrations of sulfate in waterways are observed due to various anthropogenic activities. Elevated levels of sulfate can have harmful effects on aquatic life in freshwaters: sulfate can cause osmotic stress or specific ion toxicity in aquatic organisms, especially in soft waters where Ca2+ and Mg2+ concentrations are low. Formerly, chronic toxicity test data in soft water have been scarce. The chronic and acute sulfate toxicity tests conducted with aquatic organisms from 10 families across various trophic levels in this study multiplied the number of tests conducted in soft freshwater conditions and enabled derivation of the species sensitivity distribution (SSD) and sulfate haz…

New applications of zoobenthos measurements for risk assessment of chemicals in aquatic ecosystems

2015

Artikkeliväitöskirja. Yhteenveto-osa ja viisi artikkelia. (Artikkelit eivät avoimesti saatavilla.) Article dissertation. An introduction and five articles (not available in this version). Benthic animals in aquatic ecosystems suffer from various anthropogenic pollutants. A challenge in risk assessment of chemicals in aquatic ecosystems (i.e. ecological risk assessment) has been to balance cost-efficiency and effectiveness in detecting early warning signals of chemicals. In this study, hyperspectral imaging and behavioural measurements were evaluated as novel applications for detecting chemical effects on benthic animals, and the reliability of the incidence of chironomid morphological defor…

Parasite avoidance behaviours in aquatic environments

2018

Parasites, including macroparasites, protists, fungi, bacteria and viruses, can impose a heavy burden upon host animals. However, hosts are not without defences. One aspect of host defence, behavioural avoidance, has been studied in the terrestrial realm for over 50 years, but was first reported from the aquatic environment approximately 20 years ago. Evidence has mounted on the importance of parasite avoidance behaviours and it is increasingly apparent that there are core similarities in the function and benefit of this defence mechanism between terrestrial and aquatic systems. However, there are also stark differences driven by the unique biotic and abiotic characteristics of terrestrial …

Environmental drivers of lake profundal macroinvertebrate community variation : implications for bioassessment

2011

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…

Exposure assessment of animals to sediments contaminated by pulp and paper mills

2007

Sellu- ja paperiteollisuuden jätevesillä on haittavaikutuksia kaloihin ja muihin vesieläimiin vielä senkin jälkeen, kun vierasaineet ovat hautautuneet vesistön pohjaan osaksi sedimenttiä eli järven pohjaan kerrostunutta ainesta. Vierasaineet voivat vapautua takaisin eliöille saatavaan muotoon, jos vesi sekoittuu voimakkaasti esimerkiksi ruoppauksen tai rajujen myrskyjen yhteydessä. Myös sedimentissä asustaviin pohjaeläimiin kertyy sellu- ja paperiteollisuuden vierasaineita. FM Päivi Meriläinen tutki väitöskirjassaan sellu- ja paperiteollisuuden saastuttamien sedimenttien altistamia vesieläimiä Etelä-Saimaan alueella. Sellu- ja paperiteollisuuden jätevesien haittavaikutuksia kaloihin ja muih…