The influence of organic ligands on the growth of phytoplankton in the northwest African upwelling region |
| |
Authors: | Smith Walker O Jr; Barber Richard T; Huntsman Susan A |
| |
Institution: | 1Department of Botany and Program in Ecology, The University of Tennessee Knoxville, TN 37996
2Duke University Marine Laboratory Beaufort, NC 28516
3Ralph M. Parsons Laboratory, Massachusetts Institute of Technology Cambridge, MA 02139, USA |
| |
Abstract: | Chelation bioassays were conducted off the coast of northwestAfrica during two seasons. The first (winter) was characterizedby strong shelf-break upwelling and the second (spring) wascharacterized by upwelling closer to shore. Phytoplankton insamples taken from surface waters during winter showed a markedstimulation in growth upon addition of the artificial chelatorEDTA. Optimal concentrations of the ligand were 106 M.No stimulation was observed during upwelling conditions encounteredin the spring. Primary productivity in the winter season wassignificantly lower than in the spring, averaging only 35% ofthe spring rates. Ionic copper additions reduced growth in phytoplanktonassayed in the spring and the growth reductions were eliminatedby addition of EDTA. It is hypothesized that the winter growthdepression resulted from either (1) a lack of organic compoundscapable of binding ionic copper as a result of either a lackof organic input from the sediments or surface waters becauseof direct advection to the surface, or by (2) the upwellingof water from a ligand-deficient water mass whose relative importanceas a source for newly upwelled water declined and disappearedas the season progressed. |
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|