The Fatty Acid Profile of the Deep‐Sea Gastropod Parvaplustrum wareni Indicates a Dominant Role of Chemosynthesis in the Nutrition of the Hydrothermal Vent Ecosystem (Piip Volcano)

Abstract

The gastropod Parvaplustrum wareni (Parvaplustridae) is an important faunal component in the ecosystem of deep‐sea hydrothermal vents of the Piip submarine volcano, Bering Sea. To highlight trophic relationships in this ecosystem, the fatty acid (FA) composition of the hydrothermal gastropod P. wareni has been studied. This is one of the few studies analyzing FA compositions of gastropods in a hydrothermal vent ecosystem. The major polyunsaturated FAs of this mollusk are represented by n‐3 and n‐6 FAs: arachidonic acid (20:4n‐6), eicosapentaenoic acid (20:5n‐3), docosatetraenoic acid (22:4n‐6), and docosapentaenoic acid (22:5n‐3). The low level of FA markers of phytoplankton suggests an insignificant role of organic matter created by photosynthesis in the nutrition of P. wareni. A high level of monounsaturated FAs (more than 70% of total FAs) dominated by palmitoleic (16:1n‐7) and cis‐vaccenic (18:1n‐7) FAs indicates the bacterial nutrition of the mollusk. In general, the analysis of the P. wareni FA composition has allowed a conclusion that the organic matter created by chemosynthesis provides a favorable basis for the P. wareni population to thrive in the hydrothermal vents of the Piip volcano.