Change search
ReferencesLink to record
Permanent link

Direct link
Functional significance of dinitrogen fixation in sustaining coral productivity under oligotrophic conditions
Show others and affiliations
Number of Authors: 8
2015 (English)In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, no 1818, 20152257Article in journal (Refereed) Published
Abstract [en]

Functional traits define species by their ecological role in the ecosystem. Animals themselves are host-microbe ecosystems (holobionts), and the application of ecophysiological approaches can help to understand their functioning. In hard coral holobionts, communities of dinitrogen (N-2)-fixing prokaryotes (diazotrophs) may contribute a functional trait by providing bioavailable nitrogen (N) that could sustain coral productivity under oligotrophic conditions. This study quantified N-2 fixation by diazotrophs associated with four genera of hermatypic corals on a northern Red Sea fringing reef exposed to high seasonality. We found N-2 fixation activity to be 5- to 10-fold higher in summer, when inorganic nutrient concentrations were lowest and water temperature and light availability highest. Concurrently, coral gross primary productivity remained stable despite lower Symbiodinium densities and tissue chlorophyll a contents. In contrast, chlorophyll a content per Symbiodinium cell increased from spring to summer, suggesting that algal cells overcame limitation of N, an essential element for chlorophyll synthesis. In fact, N-2 fixation was positively correlated with coral productivity in summer, when its contribution was estimated to meet 11% of the Symbiodinium N requirements. These results provide evidence of an important functional role of diazotrophs in sustaining coral productivity when alternative external N sources are scarce.

Place, publisher, year, edition, pages
2015. Vol. 282, no 1818, 20152257
Keyword [en]
diazotrophs, Symbiodinium, hermatypic corals, nitrogen fixation, photosynthesis, organic matter release
National Category
Biological Sciences
URN: urn:nbn:se:su:diva-124766DOI: 10.1098/rspb.2015.2257ISI: 000364850200022OAI: diva2:891883
Available from: 2016-01-08 Created: 2016-01-04 Last updated: 2016-01-08Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Foster, Rachel A.
By organisation
Department of Ecology, Environment and Plant Sciences
In the same journal
Proceedings of the Royal Society of London. Biological Sciences
Biological Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 14 hits
ReferencesLink to record
Permanent link

Direct link