Penetration of Bomb 14C Into the Deepest Ocean Trench

Abstract

AbstractThe food source of hadal endemic fauna provides an insight into the carbon cycle in trenches and a biological adaptation to the impoverished and harsh trench environment. Here, we present the first Δ14C results of hadal amphipods from three trenches in the Pacific to define the organic matter source in these remote ecosystems. Amphipod muscle tissues contain a bomb 14C signature (Δ14C from 10 ± 2‰ to 65 ± 2‰), thereby revealing a dietary preference for labile and fresh organic matter derived from the surface water. Thus, the carbon cycle in the deepest ocean trench has a tight linkage with the surface ocean via the food chain. The bomb 14C dating result suggests that hadal amphipods have a low tissue turnover rate and an unexpectedly long lifetime (>10 years), at more than 4 times higher than the common longevity (~2 years) of amphipods in shallow waters.