HAGFISH IN THE NEW ZEALAND FJORDS ARE SUPPORTED BY CHEMOAUTOTROPHY OF FOREST CARBON.

Forest litter is often considered to be a minor energy source to marine communities due to its refractory nature. Large volumes of forest litter are deposited in the New Zealand fjords, and likely recycled into available energy by microbial activity. In this study we used evidence from stable isotope analyses to test whether recycled carbon from chemoautotrophs was an important contributor to the diet of hagfish (Eptatretus cirrhatus). We then analyzed fatty acid biomarkers from the chemoautotrophic clam Solemya parkhlsoni and E. cirrhatus to further discriminate the contribution of marine, terrestrial, and chemoautotrophic sources. Bulk isotopic signatures of E. cirrhatus varied considerably (δ13C, from -29.2‰ to -16.7‰; δ15N, from -2.8‰ to +15.5‰; δ34S, from -21.7‰ to +16.7‰) and indicated that a significant percentage of organic matter (38-51%) originated from chemoautotrophs (δ13C, -31.3‰ ± 0.1‰ [mean ± SE]; δ15N, -5.7‰ ± 0.2‰; δ34S, -32.4‰ ± 3.8‰). Fatty acid biomarkers were depleted in 13C, particularly cis-vaccenic acid (18:1ω7: δ13C, -39.0‰) indicating specific microbial origins of carbon. A high proportion of forest litter in sediments, coupled with isotopic and fatty acid biomarker results, indicates that terrestrial organic matter is a dominant contributor to this marine benthic system. This study demonstrates a clear linkage between terrestrial and marine ecological processes. [ABSTRACT FROM AUTHOR]