The Trophic Ecology of Psammechinus miliaris in Scottish Sea Lochs

Understanding the trophic relationships between organisms is crucial to understanding ecosystem functioning and as such regular echinoids have been termed keystone through the action of their grazing. Much research has focused on this group’s action as herbivores, but as a group omnivory is common. The aim of this study was to investigate the trophic ecology of the locally super abundant regular echinoid species Psammechinus miliaris within<br/>Scottish sea lochs. To do this the study used manipulative field experiments combined with biochemical analysis of trophic proxies. The manipulative field experiments involved either the hand removal or the caging of P. miliaris to determine the impact the sea urchin grazinghas on benthic community structure. These studies revealed that grazing of P. miliaris can have a major influence on the biomass and structure of the benthic invertebrate<br/>communities. The biochemical analysis of trophic proxies was used to quantify the spatial and temporal variations in the trophic interactions of P. miliaris. These studies focused on the urchin gonad and compared differences in the gonadal somatic indices (reflecting nutritional and reproductive state) with the fatty acid biochemistry and stable isotope ratios of Carbon and Nitrogen. These studies revealed high levels of spatial and temporal heterogeneity in the trophic interactions of P. miliaris and suggested that the populations<br/>exhibited significant levels of omnivory. The combination of these studies showed that P.miliaris plays an important role in structuring benthic invertebrate communities and in the flow of energy through ecosystems and through this, ecosystem functioning.

Name dc:type.qualificationname

Doctor of Philosophy (awarded by OU/Aberdeen)

Level dc:type.qualificationlevel

Doctoral Thesis

Grantor dc:publisher.institution

The Open University

Year dc:date.issued

2006

Author dc:creator

• Hughes, Adam

Advisor dc:contributor.advisor

• Barnes, Dave

Language dc:language

eng

Identifier

oai:pure.atira.dk:studenttheses/e43ce06b-4b20-4582-9beb-bdbc61b7a214

OAI identifier oai:identifier

oai:pure.atira.dk:studenttheses/e43ce06b-4b20-4582-9beb-bdbc61b7a214