Ecology of Algal Mats from Hypersaline Ponds in the British Virgin Islands

doi:2006.21.2.235

Algae > Volume 21(2); 2006 > Article

Algae 2006;21(2): 235-243. doi: https://doi.org/10.4490/algae.2006.21.2.235

Lianna Jarecki¹, Sarah M. Burton-MacLeod² and David J. Garbary²^*

¹H. Lavity Stoutt Community College, Road Town, Tortola, British Virgin Islands
²Department of Biology, St. Francis Xavier University, Box 5000 Antigonish, Nova Scotia, Canada B2G 2W5

ABSTRACT

Benthic sediment samples ranging from poorly aggregated sand to complex, stratified mats were collected from six hypersaline ponds from March and July 1995 in the British Virgin Islands. Assemblages were analyzed with respect to species composition and abundance within visibly distinct layers in each mat sample. In individual ponds there was no apparent association between changing depth and the development of the benthic mats. Some species were present in all samples (e.g. Oscillatoria sp.) while others were restricted to single sites (e.g. Johannesbaptistia pellucida). Primary species included Microcoleus chthonoplastes, Phormidium spp., Coccochloris stagnina, and purple sulfur bacteria. Quantitative analysis of community structure included cluster and principal component analysis. Samples from individual ponds were often clustered; however, this was subject to seasonal variation. Mats collected in March were generally thicker and contained more layers than those in July. Variation among sites was not explained by the measured variation in environmental factors such as average pond salinity, depth, and oxygen concentration (mg/L). This study provides a detailed analysis of mat communities in hypersaline ponds and compares them with similar mat communities from other areas.

Key words: algal mats, British Virgin Islands, Caribbean Sea, Cyanobacteria, hypersaline ponds