Presenter: Elizabeth Miller (University of Hawaii at Manoa)
Description:
Abyssal communities across the ocean have been found to have a carbon demand exceeding that of the particulate organic material (POM) supply as determined by particle collection in near-bottom sediment traps. One potential source of this missing food supply is small, slowly sinking particles, which may be under-sampled in sediment traps. We used stable isotope analysis to identify sources of POM utilized by abyssal food webs at two sites in the North Pacific. The δ15N and δ13C values of individual amino acids can provide information about origins, composition, and extent of microbial alteration of detrital particles throughout the water column. Previous δ15N and δ13C values of individual amino acids at Station ALOHA (North Pacific Subtropics) showed that particles undergo significant microbial breakdown as they settle through the water column, and that small particles (<53 µm) are particularly important for lower mesopelagic and upper bathypelagic food webs. This work expands those findings to abyssal depths by measuring the δ15N and δ13C values of amino acids in sub-micron (<1 µm), small (1-53 µm) and large (>53 µm) particles at Station ALOHA and at Station M (off the California coast). We found that the isotope composition of particles varies with size, season, depth, and location. Of note, sediment traps captured material with δ15N values that differed greatly from material filtered in situ at comparable depths, with near-bottom sediment traps capturing fresher, more metazoan-derived material. Abyssal organisms’ δ15NSource-AA values indicated utilization of a wide range of POM having undergone varying amounts of microbial reworking, but did not indicate a significant contribution from material captured in sediment traps. Our data suggest that sediment traps may not capture all POM reaching abyssal depths, and that smaller (<53 µm), slowly sinking particles may play a bigger role in pelagic-benthic coupling than has been previously appreciated.
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Full list of Authors
- Sonia Romero Romero (University of Hawaii)
- Kenneth Smith (Monterey Bay Aquarium Research Institute)
- Christine Huffard (Monterey Bay Aquarium Research Institute)
- Brian Popp (University of Hawaii)
- Jeffrey Drazen (University of Hawaii)
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AMINO ACID STABLE ISOTOPE COMPOSITION OF PARTICULATE ORGANIC MATTER IN THE NORTH PACIFIC REVEALS ABYSSAL COMMUNITY UTILIZATION OF SMALL PARTICLES
Category
Scientific Session > OB - Ocean Biology and Biogeochemistry > OB18 Illuminating the ecological and biogeochemical dynamics of the Twilight Zone
Description
Presentation Preference: Poster
Supporting Program: None
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