ABSTRACT

The most major paradigm shift in the ocean carbon cycle grew from extensive research carried out in the 1990s—largely driven by growing concerns about the effects on ocean processes of increasing atmospheric carbon dioxide levels. Various multi-disciplinary teams published results from analysis of the origins, distribution, and analysis of recalcitrant dissolved organic matter (DOM) collected during research cruises and this led to the realization that there is a huge, ancient reservoir of organic carbon compounds in the deep ocean. In addition to purely physical factors, the “biological carbon pump” is responsible for massive redistribution of organic carbon in the oceans. About 50% of the daily net production from photosynthesis enters the ocean system as DOM, which supports the growth of heterotrophic microbes via the microbial loop, resulting in greater retention of dissolved nutrients in the upper layers of the ocean.