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Ecological differentiation between sympatric pseudocryptic species in the estuarine benthic diatom Navicula phyllepta (Bacillariophyceae)

Vanelslander, B. and Creach, V. and Vanormelingen, P. and Ernst, A. and Chepurnov, V.A. and Sahan, E. and Muyzer, G. and Stal, L.J. and Vyverman, W. and Sabbe, K. (2009) Ecological differentiation between sympatric pseudocryptic species in the estuarine benthic diatom Navicula phyllepta (Bacillariophyceae). Journal of Phycology, 45, 1278-1289. ISSN 0022-3646.

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Official URL: http://dx.doi.org/10.1111/j.1529-8817.2009.00762.x

Abstract

The occurrence of cryptic and pseudocryptic species, often living in sympatry, is widespread among microalgae. This phenomenon raises important questions about niche partitioning between these closely related species. To date, however, few studies have addressed the ecological mechanisms underlying sympatry in cryptic and pseudocryptic species. As a result, we have only a limited understanding of the factors that govern their distribution along environmental gradients. Here, we used the ribosomal internal transcribed spacer (ITS), 18S rRNA gene, and the RUBISCO LSU (rbcL) chloroplast gene sequence data together with cell wall morphology to show that estuarine populations of the widespread and common benthic diatom Navicula phyllepta Kutz. consist of pseudocryptic species. Growth rate measurements in function of salinity showed that N. phyllepta strains assigned to the different species differed in their tolerance to low salinities (< 5 practical salinity units, psu), whic! h was reflected by their different (but widely overlapping) distribution in the Westerschelde estuary (the Netherlands). Multiple regression analyses of the factors determining the abundance of the different species in field samples revealed that, in addition to salinity, sediment type and ammonium concentrations were probably equally important. Our results show that N. phyllepta sensu lato comprises different species with specialized ecophysiological characteristics rather than generalists with a broad adaptability to different environmental conditions.

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:6204
Deposited On:23 Mar 2010 01:00
Last Modified:24 Apr 2012 16:45

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