| This dissertation explores the natural capacity of the ocean's biological pump to transport particulate matter into the ocean interior. Research presented includes field observations from the Southern Ocean and global synthesis and modeling estimates of flux to depth. Within the Southern Ocean relationships between climatic forcings and the response of marine biogeochemical cycles are examined. Research presented indicates that pelagic to benthic coupling of carbon, nitrogen, and phosphorus is related to upper ocean biological community structure. Non-Redfield dissolved nutrient drawdown ratios specific to diatom and Phaeocystis antarctica communities sustain in the suspended, sinking, and sedimentation of particulate matter of the Ross Sea. A synthesis of global estimates of production, export, and flux to depth reveals pronounced regional variability in the vertical flux of particulate organic carbon in the ocean interior. Results indicate that commonly applied flux relationships, while representative of some of areas the ocean, generally overestimate flux to depth. A one-dimensional ocean model shows that the residence time of biogenic carbon in the ocean may vary by up to two orders of magnitude depending on the regional efficiency of export and vertical transport. The influences of the regional and seasonal variability of the efficiency of the ocean's biological pump are examined using global sediment trap- and satellite-based climatologies. New systems-based relationships are generated that allow for improved estimates of deep-sea particulate fluxes from satellite-based estimates of net primary production, the variability of production, and sea surface temperature. Results indicate that the fraction of primary production that reaches the deep ocean during bloom production is one to two orders of magnitude less than during minimum production. This research suggests that the seasonal variability in primary production and the interannual retention of particulate matter in the ocean interior play a significant role in flux of particulate matter in the deep ocean. |
