BIOLOGIYA MORYA, 2025, Vol. 51, No. 6, pp. 375-390

Trophic Characteristics of Bivalve Mollusks (Bivalvia) from the Shallow Shelf of the Laptev Sea

© 2025 A. V. Konoplina, S. I. Kiyashko, K. A. Lutaenko, T. N. Dautova

Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, 690041 Russia

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Bivalves (Bivalvia) are one of the main components of Arctic ecosystems, but their trophic ecology is poorly understood. This study presents the trophic characteristics of bivalves found along a submeridional transect from the Lena River delta to the northern shelf boundary during an expedition aboard the R/V Akademik Mstislav Keldysh (cruise No. 73) in the Laptev Sea in September-October 2018. Based on the abiotic characteristics of the sampling stations and the δ¹³C values in the soft tissues of bivalves, four groups of stations were identified: delta-proximal stations, midshelf stations, methane seep stations, and non-methane stations at the northern shelf boundary. A decrease in the influence of terrigenous organic matter carried by the Lena River runoff on the carbon isotope composition of bivalves was observed with increasing distance from the delta: delta-proximal stations (δ¹³C -28.1 ± 0.5‰), midshelf stations (δ¹³C -24.9 ± 0.3‰), and background stations near the northern shelf boundary (δ¹³C -22.2 ± 0.9‰). At the methane stations, the δ¹³C values in Bivalvia tissues were lower than at the background stations (-27.6 ± 0.5‰ and -22.2 ± 0.9‰, respectively).

Key words: Laptev Sea, trophic characteristics, Bivalvia, stable isotopes δ¹³C and δ¹⁵N.