TY - JOUR

T1 - Saltmarsh foraminifera in the subarctic White Sea: thrive in summer, endure in winter

AU - Golikova, Elena

AU - Varfolomeeva, Marina

AU - Yakovis, Eugeniy

AU - Korsun, Sergei

PY - 2020/6/5

Y1 - 2020/6/5

N2 - Abundance and diversity of intertidal benthic foraminifera decreases towards the poles. Well studied in the temperate zone, saltmarsh foraminiferal assemblages have only recently received attention at higher latitudes. We report modern foraminifera, including the taxonomy, abundance, and zonation, from a pristine saltmarsh in the subarctic White Sea, northern Europe. We sampled 10 stations (surface sediment, two replicates) from two high-tide flats covered with lush halophytic plants. Nine foraminiferal species found exhibited distinct vertical zonation confined to certain elevation levels. The high marsh assemblage comprised arenaceous Balticammina pseudomacrescens, Trochammina inflata, Jadammina macrescens, and monothalamous Ovammina opaca. This is the northernmost location where the first two species have been encountered alive. The low marsh assemblage was dominated by Miliammina fusca and Elphidium williamsoni. Summer abundances of live foraminifera were surprisingly higher than on other subarctic saltmarshes studied, mostly 100–500 and up to 3000 per 10 cm³. In winter, under a 40 cm of ice, the abundances were only 15–20 ind./10 cm³, but the species richness was the same. Unlike summer specimens of calcareous foraminifera, which are always brightly colored, winter Elphidium williamsoni all had bleak colorless cytoplasm, suggesting they discard kleptoplasts and abandon algal diet. We conclude that the insulating blanket of fast ice, which hardly moves on saltmarshes, prevents elimination of foraminifera in the harshness of winter, whereas the intense continental heating in summer lets them thrive on White-Sea saltmarshes. The composition of foraminiferal assemblages under local climatic conditions may thus deviate substantially from the latitudinal trend.

AB - Abundance and diversity of intertidal benthic foraminifera decreases towards the poles. Well studied in the temperate zone, saltmarsh foraminiferal assemblages have only recently received attention at higher latitudes. We report modern foraminifera, including the taxonomy, abundance, and zonation, from a pristine saltmarsh in the subarctic White Sea, northern Europe. We sampled 10 stations (surface sediment, two replicates) from two high-tide flats covered with lush halophytic plants. Nine foraminiferal species found exhibited distinct vertical zonation confined to certain elevation levels. The high marsh assemblage comprised arenaceous Balticammina pseudomacrescens, Trochammina inflata, Jadammina macrescens, and monothalamous Ovammina opaca. This is the northernmost location where the first two species have been encountered alive. The low marsh assemblage was dominated by Miliammina fusca and Elphidium williamsoni. Summer abundances of live foraminifera were surprisingly higher than on other subarctic saltmarshes studied, mostly 100–500 and up to 3000 per 10 cm³. In winter, under a 40 cm of ice, the abundances were only 15–20 ind./10 cm³, but the species richness was the same. Unlike summer specimens of calcareous foraminifera, which are always brightly colored, winter Elphidium williamsoni all had bleak colorless cytoplasm, suggesting they discard kleptoplasts and abandon algal diet. We conclude that the insulating blanket of fast ice, which hardly moves on saltmarshes, prevents elimination of foraminifera in the harshness of winter, whereas the intense continental heating in summer lets them thrive on White-Sea saltmarshes. The composition of foraminiferal assemblages under local climatic conditions may thus deviate substantially from the latitudinal trend.

KW - foraminifera

KW - kleptoplasts

KW - living assemblages

KW - saltmarsh

KW - sub-ice winter densities

KW - subarctic

KW - GLOBAL PATTERNS

KW - CHUPA INLET

KW - ST-LAWRENCE

KW - LEVEL INDICATORS

KW - ICE

KW - COMMUNITIES

KW - KANDALAKSHA BAY

KW - MYTILUS SPP.

KW - LIVING FORAMINIFERA

KW - DIVERSITY

UR - http://www.scopus.com/inward/record.url?scp=85081672621&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/9284c606-52e9-3946-9c32-4882a54b1ee6/

U2 - DOI: 10.1016/j.ecss.2020.106685

DO - DOI: 10.1016/j.ecss.2020.106685

M3 - Article

VL - 238

JO - Estuarine, Coastal and Shelf Science

JF - Estuarine, Coastal and Shelf Science

SN - 0272-7714

M1 - 106685

ER -