Long term regulative effects of Atlantic climatic factors on Archipelago Sea zooplankton biomass
– a comparison with terrestrial arctic butterflies by Heta Rousi, Julia Fält-Nardmann, Pekka Niemelä & Jari Hänninen (Univ. of Turku)
impacts of climatic
control (e. g. Winter
NAO index, n:o of Ice
days, Baltic Regime
shifts) on Archipelago
biomass time series in
with an identical study
of arctic terrestrial
during the same time
frame Synthesis of
Figure 1. Acartia spp. and Bosmina longispina maritima individuals under
Figure 2. Biomass development of Acartia spp. adults in the Archipelago Sea,
SW Finland during 1966-2019.
Preliminary results and questions
• Overall zooplankton biomass has decreased
markedly in the Baltic Sea during the last 50
• Especially species of marine origin such as
Centropages hamatus, Temora longicornis,
Acartia spp. and Evadne nordmanni have
decreased in biomass.
• Other species of brackish or limnic origin such
as Eurytemora affinis or Limnocalanus
macrurus, have increased in biomass.
• Based on earlier studies we know that
temperature and salinity strongly affect the
zooplankton species in the Baltic Sea.
• We are interested, besides of further biomass
changes of aquatic zooplankton, to find out
whether the Atlantic climatic factors regulate
terrestrial arctic butterfly species in similar
Figure 3. The field station of Archipelago Research Institute /
Turku University on the island of Seili, SW Finland.
Reference: Hänninen, J. 2022. The Baltic Sea Ecosystem
Regulation Mechanism. Environmental Analysis & Ecology
Studies 9(5). doi: 10.31031/EAES.2022.09.000721.