Assessing the apparent imbalance between geochemical and biochemical indicators of meso- and bathypelagic biological activity: What the @$#! is wrong with present calculations of carbon budgets?

Adrian B. Burd, Dennis A. Hansell, Deborah K. Steinberg, Thomas R. Anderson, Javier Aristegui, Federico Baltar, Steven R. Beaupre, Ken O. Buesseler, Frank DeHairs, George A. Jackson, David C. Kadko, Rolf Koppelmann, Richard S. Lampitt, Toshi Nagata, Thomas Reinthaler, Carol Robinson, Bruce H. Robinson, Christian Tamburini, Tsuneo Tanaka

Metabolic activity in the water column below the euphotic zone is ultimately fuelled by the vertical flux of organic material from the surface. Over time, the deep ocean is presumably at steady state, with sources and sinks balanced. But recently compiled global budgets and intensive local field studies suggest that estimates of metabolic activity in the dark ocean exceed the influx of organic substrates. This imbalance indicates either the existence of unaccounted sources of organic carbon or that metabolic activity in the dark ocean is being over-estimated. Budgets of organic carbon flux and metabolic activity in the dark ocean have uncertainties associated with environmental variability, measurement capabilities, conversion parameters, and processes that are not well sampled. We present these issues and quantify associated uncertainties where possible, using a Monte Carlo analysis of a published data set to determine the probability that the imbalance can be explained purely by uncertainties in measurements and conversion factors. A sensitivity analysis demonstrates that the bacterial growth efficiencies and assumed cell carbon contents have the greatest effects on the magnitude of the carbon imbalance. Two poorly quantified sources, lateral advection of particles and a population of slowly settling particles, are discussed as providing a means of closing regional carbon budgets. Finally, we make recommendations concerning future research directions to reduce important uncertainties and allow a better determination of the magnitude and causes of the unbalanced carbon budgets.

External organisation(s)
University of Georgia, University of Miami, Virginia Institute of Marine Science, University of Southampton, Universidad de Las Palmas de Gran Canaria, University of California, Irvine, Woods Hole Oceanographic Institution, Vrije Universiteit Brussel, Universität Hamburg, University of Tokyo, University of East Anglia, Monterey Bay Aquarium Research Institute, Aix-Marseille Université, Royal Netherlands Institute for Sea Research
Deep-Sea Research. Part 2: Topical Studies in Oceanography
No. of pages
Publication date
Peer reviewed
Austrian Fields of Science 2012
106026 Ecosystem research, 105105 Geochemistry, 106022 Microbiology
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