Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2021
Erindi/veggspjald / Talk/poster E96
Höfundar / Authors: Sigurður S. Snorrason (1), Fia Finn (1), Finnur Ingimarsson (2), Haraldur R. Ingvason (2), Marina de la Camara (1), Han Xiao (1), Kalina H. Kapralova(1), Lieke Ponsioen (1), Marcos Lagunas (1), Nahal Eskafi (1), Quentin Jean B. Horta-Lacueva (1), Stefán M. Stefánsson (2)
Starfsvettvangur / Affiliations: 1. Háskóli Íslands, 2.Náttúrustofa Kópavogs
Kynnir / Presenter: Sigurður S. Snorrason
Global warming affects temperature cycles of lakes in boreal and Arctic areas, - e.g. by extending the productive season, increasing water temperature and stabilizing thermoclines during the summertime in deep lakes. Such changes can have profound effects on the life history of aquatic animals. Here we compare patterns of growth and sexual maturation in four sympatric morphs of Arctic charr in Lake Thingvallavatn, Iceland, before and after a period of rapid global warming (1975-2019). The pattern of growth has changed dramatically in all four morphs. Adult fish of all morphs were significantly larger in 2019 than in 1984, - an increase in adult fork-length of 53, 46, 30 and 17% for the small (SB) and large (LB) benthivorous charr, piscivorous (PI) and planktivorous (PL) charr, respectively. We also saw some differences in the patterns of sexual maturation, - in PL-charr both males and females tended towards later maturation in 2019 whereas female SB-charr had matured earlier in 2019. There seems little doubt that some of these changes are caused by the marked changes in the annual temperature cycle of the lake. The results will be discussed in the light of the nature of the causal relationships, i.e. direct effects of temperature on metabolism and indirect effects mediated via temperature induced changes in community structure and function. Considering hypotheses about factors shaping the life histories of the morphs we also discuss the potential fitness consequences of these changes.