Accomplishments & Reports: Drake Passage Transect

Team S-046, D. Karl et al.
University of Hawaii, SOEST, Department of Oceanography
Honolulu, HI 96822
dkarl@soest.hawaii.edu)

In 1989, we had an opportunity to collect underway water samples every two hours on a transect from the South Shetland Islands (62^oS, 57^oW) to the Beagle Channel (55^oS, 70^oW). Analyses of bacterial cell numbers and phycoerythrin-containing cyanobacteria documented a strong north-south gradient in cyanobacteria with maximum concentrations of 8.7 x 10⁶ cells per liter near the mouth of the Beagle with a two-order of magnitude decrease in cell numbers south of the Antarctic Convergence (Letelier and Karl 1989). Although cyanobacterial abundance was positively correlated with temperature the relationship was not suggested as having a "cause-and-effect" basis.

On Polar Duke 94-12 we took the opportunity of having an experienced science team in place to attempt our second Drake Passage underway sampling survey (Figure 2). On approximately 3 hr intervals beginning late on Christmas Eve and terminating on 26 Dec at 1000 hrs we obtained a surface water sample that was processed for: (1) total dissolved inorganic carbon and total alkalinity, (2) dissolved oxygen, (3) archaeoplankton abundance, (4) hydrogen peroxide, (5) bacterial and cyanobacterial cell numbers by flow cytometry, (6) dissolved organic and inorganic nutrients, (7) chlorophyll and phaeopigments, (8) virus abundance and (9) eukaryotic phytoplankton cell number and taxonomic ID. Together, these ecological data should help describe the coupled linkages among microorganisms that we initially set out to investigate during Project SANTA CLAµS.

Reference

Letelier, R. M. and D. M. Karl. 1989. Phycoerythrin-containing cyanobacteria in surface waters of the Drake Passage during February 1987. Antarctic Journal of the United States, 24: 185-188.