Assessing the trophic link between primary and secondary producers in the Southern Ocean: A carbon-biomass based approach

Abstract

Scarcity of Carbon estimates from the biogeochemically important Southern Ocean (SO), if addressed better, can help in improving the present understanding of the Carbon (C) cycle of the region. We present estimates of standing stock of Carbon from every species, as well as the entire copepod community from this region during austral summer. Of the total copepod community, Rhincalanus gigas (13.397 mgC) contributed the most to C stock, followed by Calanus australis (5.269 mgC) and Calocalanus sp (1.027 mgC). The harpacticoid, Microsetella norvegica and poecilostomatoid, Oncaea curvata contributed more to C stock than the cyclopoids, Oithona similis and Oithona frigida. A total of 118.96 mgC was estimated from the copepod community. The trophic efficiency (Czoo/Cphyto) of 0.48 indicated a grazing pressure and exposure of copepods to a wide range of food sizes. Our findings highlight the necessity of regular spatiotemporal observations to better understand the fine ecological fluctuations and C cycle dynamics, given the accelerated changes in SO in the last few decades.