OLI Grant: Niche Differentiation in Trichodesmium spp.

John Waterbury, Biology

Grant Funded: 2006

Members of the nitrogen fixing cyanobacterial genus Trichodesmium are capable of forming extensive blooms in the world's tropical and subtropical oceans where they contribute significantly to the cycling of C, N, P and Fe. There are at least five species of Trichodesmium, distinguished morphologically, that are often treated as monospecific entities in the biogeochemical literature even though there are numerous studies showing that different species have differing temporal and spatial patterns in situ.

As part of a PhD thesis project being initiated by Annette Hynes we would like to request OLI funds to develop a method, using our culture collection of Trichodesmium spp, to identify and enumerate species of these cyanobacteria in field samples using quantitative polymerase chain reaction (QPCR) of hetR, a gene found in nitrogen fixing filamentous cyanobacteria.

The ability to identify and quantify Trichodesmium species in the field, coupled with the characterization of key physiological properties of the individual species using laboratory cultures, should allow us to determine niche differentiation in this very important and widespread genus and ultimately provide parameters to more precisely model their contribution to the cycling of C,N,P and Fe.