Population dynamics and environmental conditions affecting Trichodesmium spp. (filamentous cyanobacteria) blooms in the south-west lagoon of New Caledonia - IRD - Institut de recherche pour le développement Access content directly
Journal Articles Journal of Experimental Marine Biology and Ecology Year : 2008

Population dynamics and environmental conditions affecting Trichodesmium spp. (filamentous cyanobacteria) blooms in the south-west lagoon of New Caledonia

Abstract

The present description of Trichodesmium spp. population dynamics and associated environmental variables is the first one using a very short sampling interval (2-3 days). Such a strategy allows a fine description of changes involving the population density and characteristics. It also tends itself to interpreting those changes from past environmental conditions. During the two surveys, 2 and 5 month-long, T. erythraeum dominated the Trichodesmium population, with temporary occurrence of T. thiebautii and five blooms could be described. These events appeared at temperatures >24 degrees C and followed, in all cases, nitrate, soluble reactive phosphorus and chlorophyll a enrichments, with a 3-7 day time lag. Low wind speed (<4 m s(-1)) was not a prerequisite for Trichodesmium bloom developments as long as temperatures exceeded 26 degrees C. As abundance increased during the bloom, so did the number of filaments (trichomes) in colonies and their buoyancy, leading to a clear positive biomass gradient from the bottom to the surface. A simple model, using variable growth rates, showed trichome ascent would be responsible for 87-99% of concentrations at 0.5 m, with Trichodesmium net growth rates ranging from 0.11 to 0.38 d(-1). Finally, rapid trichome density declines could be ascribed to nutrient depletion and massive surface death following ascent.

Domains

Ecosystems
Fichier principal
Vignette du fichier
RodierLeBorgne.pdf (908.5 Ko) Télécharger le fichier
Origin : Files produced by the author(s)
Loading...

Dates and versions

ird-00288736 , version 1 (18-06-2008)

Identifiers

Cite

Martine Rodier, Robert Le Borgne. Population dynamics and environmental conditions affecting Trichodesmium spp. (filamentous cyanobacteria) blooms in the south-west lagoon of New Caledonia. Journal of Experimental Marine Biology and Ecology, 2008, 358 (1), pp.20-32. ⟨10.1016/j.jembe.2008.01.016⟩. ⟨ird-00288736⟩

Collections

IRD AGROPOLIS
106 View
591 Download

Altmetric

Share

Gmail Facebook X LinkedIn More