Coastal salt marshes are highly-productive vegetated areas at the upper intertidal that develop in wave-sheltered estuaries, deltas, and semi-enclosed bays. They sequester and store organic carbon and provide food, shelter and breeding sites for multiple invertebrates, fish, waterfowl and mammals. Due to their location salt marshes are vulnerable to anthropogenic impact associated with oil and gas exploration and transportation, which puts them at risk, as the petroleum industry develops in the Arctic region. The present levels of chemical contamination in the subarctic White Sea still allow to establish reference sites in pristine environments that can be further used in environmental monitoring studies. Foraminiferans are meiofaunal protists common in salt marshes and well suited for environmental monitoring due to their diversity, abundance, reproduction rate, and presence of stress-tolerant taxa. The salt-marsh foraminiferal assemblages at the White Sea have never been surveyed yet.
Here, we related the species compositions of the foraminiferans and vascular plants from the two undisturbed salt marshes in the White Sea. We identified 9 foraminiferal species: Jadammina macrescens, Balticammina pseudomacrescens, Trochammina inflata, Miliammina fusca, Ovammina opaca, Elphidium williamsoni, Elphidium albiumbilicatum, Ammotium salsum, Ammobaculites exiguus, which grouped into two distinct assemblages ('high marsh' and 'low marsh') each confined to certain vascular vegetation belts. Foraminiferans J. macrescens, B. pseudomacrescens, T. inflata resided at high marsh and were associated with reed foxtail Alopecurus arundinaceus, black-grass Juncus gerardii and sea plantain Plantago maritima, whereas M. fusca and E. williamsoni dwelled at low marsh and were associated with annual glasswort Salicornia pojarkovae and seashore alkali grass Puccinellia maritima. The foraminiferal species diversity of the studied subarctic salt marshes is lower than in temperate regions (approximately 10-30 species) but remains unexpectedly high (9 species). The White Sea salt-marsh foraminiferal fauna is highly abundant (up to 3000 living specimens per 10cm³). Expected disturbance thus can be traced using foraminiferal abundance and species diversity. We acknowledge the RFBR grant 14-04-93083 and OSL-14-11 grant.