Benthic respiration measured by total carbonate production

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Abstract
The suitability of total carbonate production instead of oxygen consumption as a measure of benthic respiration has been investigated. In situ fluxes of total carbonate, oxygen, calcium, total alkalinity, nutrients, and sulfide across the sediment‐water interface were measured in diver‐operated benthic flux chambers. Two chambers were run in parallel to test the influence of oxygen and pH levels on total carbonate production. In one, oxygen and pH were kept constant near ambient levels; in the other, benthic respiration was allowed to deplete oxygen and lower the pH. We found that the flux of total carbonate, corrected for CaCO3 precipitation/dissolution, is a suitable measure of benthic mineralization in sediments where methane production can be neglected. The production rate of total carbonate was not seriously affected as long as the oxygen concentration remained > 100 µM.