title: Multi-decadal range changes vs. thermal adaptation for north east Atlantic oceanic copepods in the face of climate change.
abstract: Populations may potentially respond to climate change in various ways including moving to new areas or alternatively staying where they are and adapting as conditions shift. Traditional laboratory and mesocosm experiments last days to weeks and thus only give a limited picture of thermal adaptation, whereas ocean warming occurring over decades allows the potential for selection of new strains better adapted to warmer conditions. Evidence for adaptation in natural systems is equivocal. We used a 50-year time series comprising of 117 056 samples in the NE Atlantic, to quantify the abundance and distribution of two particularly important and abundant members of the ocean plankton (copepods of the genus Calanus) that play a key trophic role for fisheries. Abundance of C. finmarchicus, a cold-water species, and C. helgolandicus, a warm-water species, were negatively and positively related to sea surface temperature (SST) respectively. However, the abundance vs. SST relationships for neither species changed over time in a manner consistent with thermal adaptation. Accompanying the lack of evidence for thermal adaptation there has been an unabated range contraction for C. finmarchicus and range expansion for C. helgolandicus. Our evidence suggests that thermal adaptation has not mitigated the impacts of ocean warming for dramatic range changes of these key species and points to continued dramatic climate induced changes in the biology of the oceans.
authors: Institute of Life Sciences, Swansea University, Singleton Park, Swansea, SA2 8PP, UK; Department of Biosciences, Swansea University, Singleton Park, Swansea, SA2 8PP, UK; The Laboratory, SAHFOS, Citadel Hill, Plymouth, PL1 2PB, UK.
authors: Stephanie L
authors: SL
authors: Hinder
authors: Mike B
authors: MB
authors: Gravenor
authors: Martin
authors: M
authors: Edwards
authors: Clare
authors: C
authors: Ostle
authors: Owen G
authors: OG
authors: Bodger
authors: Patricia L M
authors: PL
authors: Lee
authors: Antony W
authors: AW
authors: Walne
authors: Graeme C
authors: GC
authors: Hays
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001267:Atlantic Ocean; D044822:Biodiversity; D057231:Climate Change; D033342:Copepoda / Q000502:physiology*; D011156:Population Density; D013696:Temperature
keywords: Mesozooplankton; NAO; bottom up control; climate change; copepods; long-term changes; sea surface temperature; top down control; westerly wind