UNDER CONSTRUCTION |
You can find the PDF of the publications cited below on my 'Publications' page. Alternatively, you can request them by e-mail. My collaborators and links to their webpages are listed on my 'CV' page.
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Benthic Community Metabolism
(c) N. Spilmont
Intertidal
soft sediments have long been suspected to be major contributors the global
primary production and respiration of coastal areas. However, in most of the
early studies that aimed to estimate benthic fluxes in these environments, the
substratum (and therefore the related fauna and flora) had to be manipulated.
Indeed, most measurements were performed in the lab, and only during immersion
periods. In this context, a benthic chamber was developped, that allowed in
situ measurement of CO2 exchanges (infrared gas analysis) at the
community level in intertidal soft sediments (Publication 1).
Surveys were performed on several study sites
along the French coast of the English Channel. The seasonal variations of the
benthic metabolism were examined and permitted the calculation of annual budgets
at the m2 scale. No clear relationship was detected between biomasses and
fluxes and global budgets depended mainly on variations in light, temperature
and tidal cycle at scales ranging from hours to seasons (Publications 4, 6, 12, 18).
In the context of global warming and the rise of atmospheric CO2
concentrations, these data are critical to determine whether intertidal areas
constitute a source or a sink of CO2. Their status is still
uncertain and further studies are still needed (Publication 15).
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Spatio-temporal Variability of Processes and Biomass Distributions
(c) N. Spilmont
Realistic budgets of CO2 fluxes are obtained
only when the short-term (microphytobenthos migration) and daily (tidal cycle) variability
of the processes is taken into account (Publications 7, 12). Furthermore,
exceptional and unpredictable events (such as the Phaeocystis bloom in the Eastern English Channel) may have profound
impacts on intertidal processes but remain difficult to consider, both in space
and time, in budget calculations (Publications 5, 9, 18, 21). We have also shown that benthic CO2 fluxes inconsistently vary along a range of spatial scales, from a
few m to 100s of km (Publication 10).
Microphytobenthos (benthic microalgae that live
in the first few mm of the sediment) distributions are highly heterogeneous.
These distributions exhibit multifractal properties and some fingerprints for
self-organized criticality (Publication 2). Besides being another proof of the
universality of the fractal patterns, this has profound implications
for the sampling of Chla as a
descriptor of microphytobenthos biomass (Publication 14) and may drive the
behavior/distribution of their grazers (more to read soon…hopefully!).
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Tools have recently been developed or adapted to the sediment and allow the estimation microphytobenthos biomass and primary production with non-destructive methods (Spectral reflectance and PAM fluorescence). They are useful to examine the processes occurring at microscale that govern the overall fluxes at the community level, and can also be used for the mapping of Chla at large scales (Publications 3, 8).
In the framework of the CHARM (Channel Habitat Atlas for marine Resource Management) project, I also investigated the large scale distribution of benthic species to help managing the living resources of the English Channel (Publication 13). However, even in a management context, ecology-related words should be used with caution (Publication 17)!
In the framework of the CHARM (Channel Habitat Atlas for marine Resource Management) project, I also investigated the large scale distribution of benthic species to help managing the living resources of the English Channel (Publication 13). However, even in a management context, ecology-related words should be used with caution (Publication 17)!
Sources and fate of organic matter in benthic communities
Trypaea australiensis. (c) N. Spilmont
The fate of the organic matter produced by
microphytobenthos was studied on a sandbank of the Gold Coast (Queensland,
Australia) where the ghost shrimp (Trypaea australiensis) and the soldier crab
(Myctyris longicarpus) were the dominant species. Their diet was studied using
fatty acids and stable isotopes biomarkers. Microphytobenthos was a source of
organic matter for both species, but was largely dominant in the shrimp’s diet,
whereas the soldier crab also fed on bacteria and meiofauna (Publication 11).
Lipids can also be used as indicators (Publications 19, 21), e.g. for the physiological status of fish (Publication 16).
Lipids can also be used as indicators (Publications 19, 21), e.g. for the physiological status of fish (Publication 16).