Gordon, L. I.. Oregon State University, 541-737-2064
Jennings, Jr., J. I.. Same, jenningj@oce.orst.edu
Ross, A. A.. Same, rossan@oce.orst.edu
Wilson, J. Same, wilson@oce.orst.edu

 
NUTRIENT DEPLETION RATIOS DURING THE AESOPS SOUTHERN OCEANS JGOFS STUDY
 
We measured phosphate, nitrate and silicic acid during the AESOPS effort in the Ross Sea as part of the Southern Oceans JGOFS program. AESOPS made four studies along the 76.5 degree S parallel from ca. 165 degrees E to 174 degrees W in Oct/Nov 1996 and Jan/Feb, Apr/May and Nov/Dec 1997. The relative depletions of these nutrients followed some interesting relationships and as would be expected the patterns were clearest and most intense during austral spring and summer. In the near-surface layers, for small geographic areas, sometimes at only one station or perhaps two adjacent ones, there appeared linear correlations between nitrate (N) and phosphate (P) and between silicic acid (Si) and both N and P. The number of linear segments is small; the several slopes of the N vs. P data bracket but do not in general match the classical Redfield ratio of ca. 16. The slopes group around 12 and around 20 such that one might accept a possible average around the Redfield ratio. A similar approach using Si:N and Si:P clearly shows the response of the nutrient fields to growth of prymnesiophytes versus diatoms. For example, Si:N ranged from ca. 0.1 to 2.0, the latter value reflecting the diatom growth, the former value prymnesiophyte growth and in between values reflecting mixed populations. Phosphate displayed less clear correlations.
 
Day: Wednesday, Feb. 3
Time: Poster
Location: Sweeney Center
 
Code: SS31WE1146S