Sea-ice eukaryotes of the Gulf of Finland, Baltic Sea, and evidence for herbivory on weakly shade-adapted ice algae

Abstract

To determine community composition and physiological status of early spring sea-ice organisms, we collected sea-ice, slush and under-ice water samples from the Baltic Sea. We combined light microscopy, HPLC pigment analysis and pyrosequencing, and related the biomass and physiological status of sea-ice algae with the protistan community composition in a new way in the area. In terms of biomass, centric diatoms including a distinct Melosira arctica bloom in the upper intermediate section of the fast ice, dinoflagellates, euglenoids and the cyanobacterium Aphanizomenon sp. predominated in the sea-ice sections and unidentified flagellates in the slush. Based on pigment analyses, the ice-algal communities showed no adjusted photosynthetic pigment pools throughout the sea ice, and the bottom-ice communities were not shade-adapted. The sea ice included more characteristic phototrophic taxa (49%) than did slush (18%) and under-ice water (37%). Cercozoans and ciliates were the richest taxon groups, and the differences among the communities arose mainly from the various phagotrophic protistan taxa inhabiting the communities. The presence of pheophytin a coincided with an elevated ciliate biomass and read abundance in the drift ice and with a high Eurytemora affinis read abundance in the pack ice, indicating that ciliates and Eurytemora affinis were grazing on algae.

Culturable diversity of Arctic phytoplankton during pack ice melting

“…Cells are round or elongated, ~ 7 µ m in diameter or 10 µ m long, respectively (Figure 7H). Chlamydomonas is a common genus found in the Arctic during the spring and summer months (Balzano et al, 2012; Lovejoy et al, 2002), that can occur in association with sea-ice (Majaneva et al, 2017).…”

“…The nucleus, stigma and two 7 µ m flagella can be observed (Figure 7L). Although mainly isolated from coastal and estuarine environments (Bendif et al, 2013), this genus has also been reported as characteristic of sea-ice environments (Majaneva et al, 2017).…”

“…Ice, under-ice and open water Arctic phytoplankton communities differ in diversity, biomass, growth rate and tolerance to environmental conditions (Arrigo et al, 2012). Similarly, different types of ice provide different substrates, and therefore harbor different communities (Comeau et al, 2013; Majaneva et al, 2017). The same is true for the stages of ice formation (Kauko et al, 2018; Olsen et al, 2017).…”

Photosynthetic Picoeukaryotes Diversity in the Underlying Ice Waters of the White Sea, Russia

“…Studies of the biomass plankton algae dynamics from January to April in Kandalaksha Bay also revealed the highest values in April [50]. The values of Chl a concentration obtained in the under-ice water of the White Sea are comparable to those in the under-ice water of the Baltic Sea in March (0.5-1.0 µg L −1 ) [51].…”

Progress in Microbial Ecology in Ice-Covered Seas

“…These centric diatoms are supplemented by large contributions of Melosira arctica and the cyanobacterium Aphanizomenon sp. that can predominate abundances in the brine channels (Majaneva et al 2017). In contrast to Arctic and Antarctic sea ice communities, dinoflagellates and green algae contribute to a large fraction of the biomass in Baltic Sea ice and open water (Kaartokallio et al 2007;Piiparinen et al 2010).…”