Effects of salinity on the growth rate and morphology of ten Skeletonema strains

Sergio Balzano (1) , Wiebe Kooistra (2) , Diana Sarno (2)

1 DIPO - Diversité et Interactions au sein du Plancton Océanique
2 Marine Botany

Skeletonema comprises a planktonic genus of centric diatoms occurring in coastal and brackish waters worldwide. The most commonly reported species, S. costatum, was believed to be ubiquitous, morphologically plastic and euryhaline. Yet, recent studies showed that this perceived taxon consists of a series of species, including a more narrowly defined S. costatum sensu stricto. Here we investigated the effect of salinity on growth rate and cell morphology. Ten strains belonging to six Skeletonema species were incubated at salinities between zero and 35, their growth response was measured and their cell morphology observed in light and electron microscopy. All strains grew well between salinities of 10 and 35, whereas the lowest salinity at which growth was observed differed among species and even within the same species: Skeletonema marinoi strains deriving from distinct environments (Baltic and North Sea) showed different lower tolerance limits. Two species, Skeletonema costatum and S. subsalsum, showed growth between salinities of zero and 35 and exhibited very short intercellular processes when cultured in freshwater. Skeletonema subsalsum went through cell enlargement when exposed to a salinity of 35.

Mots clés: Life Sciences

Sergio Balzano, Wiebe Kooistra, Diana Sarno. Effects of salinity on the growth rate and morphology of ten Skeletonema strains. Journal of Plankton Research, 2010, ⟨10.1093/plankt/FBQ150⟩. ⟨hal-00648048⟩