Chlorophylls and Phycoerythrins as Markers of Environmental Forcings Including Cyclone Erica Effect (March 2003) on Phytoplankton in the Southwest Lagoon of New Caledonia and Oceanic Adjacent Area

[摘要] Spatio-temporal variations of chlorophylls and phycoerythrins, inferred by spectrofluorometric methods, were studied from April 2002 to June 2003 in the southwest lagoon and oceanic waters of New Caledonia. Trade winds blew 75% of the time and appeared as the main factor influencing surface Tchla(sum of monovinyl- and divinyl-chlorophylla) variations in the ocean, near the barrier reef. Lagoon and oceanic waters differed in the composition of picoplanktonic cyanobacteria with a relative dominance ofProchlorococcusand high-phycourobilinSynechococcusin the ocean, and a relative dominance of high-phycoerythrobilinSynechococcusin the lagoon. Main pigment variations in the lagoon were associated with cyclone Erica in March 2003 and showed a 5-6 fold Tchlaincrease around Nouméa. The cyclone stimulated mainly diatom growth as indicated by the high chlorophyll (c1+c2)/chlorophyllaratio and by the lowest values for the other pigment ratios. The relative importance of divinyl-chlorophyllaconcentration and fluorescence excitation spectra of phycoerythrins appeared as useful tools for characterizing lagoon-ocean exchanges.

[学科分类] 地质学