{"id":{"repo_id":"holar","oai_identifier":"oai:skemman.is:1946/53393"},"canonical_url":"https://search.dev.ndltd.org/etd/holar/oai:skemman.is:1946/53393","repository":{"repo_id":"holar","name":"Hólar University College","base_url":"https://skemman.is/oai/request"},"display":{"title":"Crustacea Zooplankton Communities in Icelandic Lakes Comparison Over Time","abstract":"This study examines freshwater Crustacea zooplankton communities in 19 Icelandic lakes, focusing on Copepoda and Cladocera. Zooplankton form a key trophic link in freshwater ecosystems, grazing on phytoplankton and serving as prey for higher trophic levels. Monitoring biodiversity in Arctic and sub-Arctic regions is particularly important given ongoing rapid climate change. Communities were compared using data from two national surveys: the Ecological Survey of Icelandic Lakes (1992–1998) and the Natura Project (2012–2013). Multivariate statistical analyses were applied to assess temporal changes in diversity and composition and to evaluate the influence of environmental variables, including geological variables, spatial gradients, and nutrient concentrations. Mandibular morphology in Cyclops abyssorum G. O. Sars, 1863 was further examined as a case study of intraspecific variation. Species richness showed a slight but significant increase over time, whereas Pielou’s evenness declined marginally. Overall temporal changes were modest compared to spatial variability among lakes. Geological substrate, altitude, and nutrient availability were the strongest predictors of community structure. In addition, distinct mandibular morphology observed in C. abyssorum from Þingvallavatn suggests ecologically relevant intraspecific variation potentially linked to trophic conditions. These findings indicate that Icelandic Crustacea zooplankton communities remain relatively stable over decadal timescales, while subtle shifts reflect environmental gradients and ongoing ecosystem change.","abstract_html":"This study examines freshwater Crustacea zooplankton communities in 19 Icelandic lakes, focusing on Copepoda and Cladocera. Zooplankton form a key trophic link in freshwater ecosystems, grazing on phytoplankton and serving as prey for higher trophic levels. Monitoring biodiversity in Arctic and sub-Arctic regions is particularly important given ongoing rapid climate change. Communities were compared using data from two national surveys: the Ecological Survey of Icelandic Lakes (1992–1998) and the Natura Project (2012–2013). Multivariate statistical analyses were applied to assess temporal changes in diversity and composition and to evaluate the influence of environmental variables, including geological variables, spatial gradients, and nutrient concentrations. Mandibular morphology in Cyclops abyssorum G. O. Sars, 1863 was further examined as a case study of intraspecific variation. Species richness showed a slight but significant increase over time, whereas Pielou’s evenness declined marginally. Overall temporal changes were modest compared to spatial variability among lakes. Geological substrate, altitude, and nutrient availability were the strongest predictors of community structure. In addition, distinct mandibular morphology observed in C. abyssorum from Þingvallavatn suggests ecologically relevant intraspecific variation potentially linked to trophic conditions. These findings indicate that Icelandic Crustacea zooplankton communities remain relatively stable over decadal timescales, while subtle shifts reflect environmental gradients and ongoing ecosystem change.","abstract_has_math":false,"creators":["Þóra Atladóttir 1980-"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Háskólinn á Hólum"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2026,"date_issued":"2026-05-29T10:43:44Z","date_published":"2026-05-29T10:43:44Z","updated_at":"2026-07-27T19:56:59Z","subjects":["Sjávar- og vatnalíffræði","Dýrasvif","Ferskvatn","Líffræðileg fjölbreytni","Vistkerfi"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/1946/53393","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Háskólinn á Hólum"]},{"key":"dc:creator","label":"Author","values":["Þóra Atladóttir 1980-"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2026-05-29T10:43:38Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2026-05-29T10:43:38Z"]},{"key":"dc:date.issued","label":"Date","values":["2026-05-29T10:43:44Z"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Sjávar- og vatnalíffræði","Dýrasvif","Ferskvatn","Líffræðileg fjölbreytni","Vistkerfi"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/1946/53393"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This study examines freshwater Crustacea zooplankton communities in 19 Icelandic lakes, focusing on Copepoda and Cladocera. Zooplankton form a key trophic link in freshwater ecosystems, grazing on phytoplankton and serving as prey for higher trophic levels. Monitoring biodiversity in Arctic and sub-Arctic regions is particularly important given ongoing rapid climate change. Communities were compared using data from two national surveys: the Ecological Survey of Icelandic Lakes (1992–1998) and the Natura Project (2012–2013). Multivariate statistical analyses were applied to assess temporal changes in diversity and composition and to evaluate the influence of environmental variables, including geological variables, spatial gradients, and nutrient concentrations. Mandibular morphology in Cyclops abyssorum G. O. Sars, 1863 was further examined as a case study of intraspecific variation. Species richness showed a slight but significant increase over time, whereas Pielou’s evenness declined marginally. Overall temporal changes were modest compared to spatial variability among lakes. Geological substrate, altitude, and nutrient availability were the strongest predictors of community structure. In addition, distinct mandibular morphology observed in C. abyssorum from Þingvallavatn suggests ecologically relevant intraspecific variation potentially linked to trophic conditions. These findings indicate that Icelandic Crustacea zooplankton communities remain relatively stable over decadal timescales, while subtle shifts reflect environmental gradients and ongoing ecosystem change.","Í ritgerðinni eru samfélög ferskvatns-svifkrabbadýra skoðuð með áherslu á árfætlur og vatnaflær. Svifdýr sinna lykilhlutverki í fæðukeðju ferskvatnsvistkerfa með þörungaáti og sem fæða fyrir lífverur ofar í fæðukeðjunni. Eftirlit með líffræðilegri fjölbreytni á norðurslóðum er sérstaklega mikilvægt í ljósi þeirra hröðu loftslagsbreytinga sem nú eiga sér stað. Samfélög voru borin saman með gögnum úr tveimur íslenskum rannsóknum: Yfirlitskönnun á lífríki íslenskra vatna: samræmdur gagnagrunnur (1992–1998) og Natura verkefni (2012–2013). Fjölbreytu-greining var gerð til að meta breytingar á fjölbreytni og samsetningu samfélaga yfir tíma og til að meta áhrif umhverfisþátta, þar á meðal jarðfræðilegir þættir, staðbundnir þættir og magn næringarefna. Formfræði munnlima í Cyclops abyssorum G. O. Sars, 1863 var skoðuð sem hluti af forrannsókn í tengslum við innantegunda breytileika. Tegundafjölbreytni jókst örlítið en þó marktækt milli verkefna á meðan Pielou’s jafnræði minnkaði lítillega. Á heildina litið voru breytingar yfir tíma fremur litlar miðað við staðbundnar breytur. Berggrunnur, hæð og magn næringarefna voru helstu áhrifaþættir í tegundasamsetningu samfélaganna. Auk þess bendir formbreyting í gerð tanna í munnlimum C. abyssorum í Þingvallavatni til innantegundabreytileika, sem mögulega tengjast fæðuskilyrðum. Þessar niðurstöður benda til að íslensk svifkrabbadýra samfélög í ferskvatni haldist nokkuð stöðug yfir tíma, en lítilsháttar breytingar samfélaganna endurspegla umhverfisþætti og stöðugar breytingar vistkerfa."]},{"key":"dc:title","label":"Title","values":["Crustacea Zooplankton Communities in Icelandic Lakes Comparison Over Time"]}]}],"canonical_facts":{"dc:contributor":["Háskólinn á Hólum"],"dc:creator":["Þóra Atladóttir 1980-"],"dc:date.accessioned":["2026-05-29T10:43:38Z"],"dc:date.available":["2026-05-29T10:43:38Z"],"dc:date.issued":["2026-05-29T10:43:44Z"],"dc:description.abstract":["This study examines freshwater Crustacea zooplankton communities in 19 Icelandic lakes, focusing on Copepoda and Cladocera. Zooplankton form a key trophic link in freshwater ecosystems, grazing on phytoplankton and serving as prey for higher trophic levels. Monitoring biodiversity in Arctic and sub-Arctic regions is particularly important given ongoing rapid climate change. Communities were compared using data from two national surveys: the Ecological Survey of Icelandic Lakes (1992–1998) and the Natura Project (2012–2013). Multivariate statistical analyses were applied to assess temporal changes in diversity and composition and to evaluate the influence of environmental variables, including geological variables, spatial gradients, and nutrient concentrations. Mandibular morphology in Cyclops abyssorum G. O. Sars, 1863 was further examined as a case study of intraspecific variation. Species richness showed a slight but significant increase over time, whereas Pielou’s evenness declined marginally. Overall temporal changes were modest compared to spatial variability among lakes. Geological substrate, altitude, and nutrient availability were the strongest predictors of community structure. In addition, distinct mandibular morphology observed in C. abyssorum from Þingvallavatn suggests ecologically relevant intraspecific variation potentially linked to trophic conditions. These findings indicate that Icelandic Crustacea zooplankton communities remain relatively stable over decadal timescales, while subtle shifts reflect environmental gradients and ongoing ecosystem change.","Í ritgerðinni eru samfélög ferskvatns-svifkrabbadýra skoðuð með áherslu á árfætlur og vatnaflær. Svifdýr sinna lykilhlutverki í fæðukeðju ferskvatnsvistkerfa með þörungaáti og sem fæða fyrir lífverur ofar í fæðukeðjunni. Eftirlit með líffræðilegri fjölbreytni á norðurslóðum er sérstaklega mikilvægt í ljósi þeirra hröðu loftslagsbreytinga sem nú eiga sér stað. Samfélög voru borin saman með gögnum úr tveimur íslenskum rannsóknum: Yfirlitskönnun á lífríki íslenskra vatna: samræmdur gagnagrunnur (1992–1998) og Natura verkefni (2012–2013). Fjölbreytu-greining var gerð til að meta breytingar á fjölbreytni og samsetningu samfélaga yfir tíma og til að meta áhrif umhverfisþátta, þar á meðal jarðfræðilegir þættir, staðbundnir þættir og magn næringarefna. Formfræði munnlima í Cyclops abyssorum G. O. Sars, 1863 var skoðuð sem hluti af forrannsókn í tengslum við innantegunda breytileika. Tegundafjölbreytni jókst örlítið en þó marktækt milli verkefna á meðan Pielou’s jafnræði minnkaði lítillega. Á heildina litið voru breytingar yfir tíma fremur litlar miðað við staðbundnar breytur. Berggrunnur, hæð og magn næringarefna voru helstu áhrifaþættir í tegundasamsetningu samfélaganna. Auk þess bendir formbreyting í gerð tanna í munnlimum C. abyssorum í Þingvallavatni til innantegundabreytileika, sem mögulega tengjast fæðuskilyrðum. Þessar niðurstöður benda til að íslensk svifkrabbadýra samfélög í ferskvatni haldist nokkuð stöðug yfir tíma, en lítilsháttar breytingar samfélaganna endurspegla umhverfisþætti og stöðugar breytingar vistkerfa."],"dc:identifier.uri":["https://hdl.handle.net/1946/53393"],"dc:language.iso":["en"],"dc:subject":["Sjávar- og vatnalíffræði","Dýrasvif","Ferskvatn","Líffræðileg fjölbreytni","Vistkerfi"],"dc:title":["Crustacea Zooplankton Communities in Icelandic Lakes Comparison Over Time"],"dc:type":["Thesis"]},"updated_at":"2026-07-27T19:56:59Z"}