Export and molecular level characterization of dissolved and particular organicmatter from the mid-Atlantic bight

摘要

As part of the OMP field program, Dr. Repeta served as chief scientist on twowhole shelf cruises to survey the MAB, one in late winter/ spring (February/March 1996) and one in summer (July/August, 1996). Our field program surveyed the shelf under two very different biogeochemical regimes. In the late winter/spring, river discharge and primary productivity are maximal. The water column is well mixed, relatively fresh, and has high standing stocks of nutrients and biomass. In summer, both primary production and river discharge decrease. A strong pycnccline develops that restricts the freshwater inputs to a very shallow surface layer, and isolates surface water from colder deep water (cold pool). Our objective was to inventory dissolved and particulate forms of carbon (and to the extend possible, nitrogen) in order to establish spatial gradients and seasonal patterns of elemental distribution and flux on a much wider area of the shelf than accounted for by the moored array. We proposed to use geochemical tracers that integrate over longer spatial and temporal scales to supplement C cycling studies conducted by the benthic, water column processes and moored array teams of OMP.