Takahashi, T. Lamont-Doherty Earth Observatory of Columbia University, taka@ldeo.columbia.edu
Hales, B. College of Oceanic and Atmospheric Sciences, Oregon State University, 541 737 2064
Sweeney, C. Lamont-Doherty Earth Observatory of Columbia University, csweeney@ldeo.columbia.edu

We deployed the Lamont Pumping SeaSoar, equipped with an in situ CTD and sensor array and a pump for continuous delivery of seawater samples for shipboard chemical analyses, four times during the AESOPS Ross Sea Process IV cruise (November-December 1997). Three of these were transects from 169 E to 179 E along 76 30'S. We measured in situ temperature, salinity, chlorophyll, O2, and PAR at vertical resolution <25cm and horizontal resolution <5km. We measured PCO2 and nitrate, phosphate, silicate, and TCO2 concentrations of the seawater samples delivered by the SeaSoar with several specially-developed high-speed analytical systems. All properties exhibited strong mesoscale variability and 'finger'-like vertical structure penetrating as deep as 100m, and horizontal scales 5-15km. A persistent mass of Modified Circumpolar Deep Water, identified by a pronounced temperature maximum, intruded at a depth of about 100m in the middle of the transect. Nearly vertical density contours bracket this feature, implying northerly flow at its western boundary and southerly flow on the east. With only two-dimensional coverage we cannot say whether this is a meandering current or an eddy. A low salinity cap over the warm intrusion produced well-stratified surface waters, yet was a minimum in chlorophyll productivity and macronutrient utilization.
Day: Wednesday, Feb. 3
Time: Poster
Location: Sweeney Center
Code: SS31WE0921S