Carbonate degradation, factors affecting

The final important factor affecting the solubility of CaCOs in the ocean is the concentration of carbonate ion. The high ratio of organic carbon to carbonate carbon in the particulate material degrading and dissolving in the deep sea causes the deep waters to become more acidic and carbonate-poor as they progress along the conveyor belt... 

The few studies that exist on Fe control of bacterial degradation in HNLC waters agreed that bacterio-plankton is first C-limited as a consequence of low primary production due to Fe limitation and not directly limited by Fe (Hutchins et al. 1998 Church et al. 2000 Kirchman et al. 2000). As reported above, the amount of TOC, potential OC available for bacteria, was similar in our HFe and LFe experiments and therefore bacteria could be colimited by two major factors the availability of Fe and the quality of the organic matter. These factors cannot be discriminated in our experiments. HFe bioassays contained, in addition to increased Fe, a better quality of OM than the LFe bioassays. Moreover, as the distribution in dissolved and particulate organic carbon was affected by Fe availability in the phytoplanktonic cultures, the response of bacteria to different size pool of organic matter (DOM-TOM) was also investigated. 

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