A study of nutrient dynamics in the Atlantic Ocean

• Main Author: Dahm, Clifford N.
• Other Authors: Park, P. Kilho, School of Oceanography, Oregon State University. Graduate School
• Format: Master Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: Chemical oceanography; Antarc*; Antarctic; NADW; North Atlantic Deep Water; North Atlantic
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/mc87ps745

During the GEOSECS cruise of the R/V KNORR, July 1972-April 1973, a very complete and high quality nutrient data set was acquired for the Atlantic Ocean. One hundred and twenty-one hydrographic stations were occupied throughout the Atlantic providing an internally consistent picture of the nutrient dynamics for this ocean. The dynamic and biological controls on the nutrient distribution were viewed by means of horizontal distribution patterns, vertical profiling, and statistical modeling of relationships between oxygen, potential temperature, salinity, and nutrients. The general conclusions are summarized as follows: 1. The nutrient concentrations in the Atlantic exhibit the interplay at all depths of nutrient rich waters of South Atlantic origin with nutrient poor waters of the North Atlantic. This interrelationship of the two water sources manifests itself in numerous extrema (maxima and minima) in the water column. 2. For intermediate and deep waters, the strong predominance of lateral transport over processes of vertical dissipation are apparent in the Atlantic. Identifiable water types with only small variations of potential temperature (θ), salinity (S), and preformed nutrients can be characterized thousands of miles from their region of origin. 3. Silicate distribution in the Atlantic exhibits very marked gradients between waters of South and North Atlantic origin. Variations of up to 100 μm/kg occur where salinity differences are less than 0.3‰. Great potential exists for the use of silicate as a water mass tracer for Antarctic Intermediate Water (AAIW), North Atlantic Deep Water (NADW), and Antarctic Bottom Water (AABW). 4. The deep and bottom water nutrient distribution can be explained purely from hydrodynamic considerations. Nutrients, dissolved oxygen (O₂), and apparent oxygen utilization (AOU) behave like conservative parameters. The rates of oxidation in deep water are slow relative to the physical processes of mixing and advection, 5. The total organic carbon (TOG) is relatively invariant below a ...