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Meiofaunal communities and human impacts at Casey Station, Antarctica

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Mohammad, M (2011) Meiofaunal communities and human impacts at Casey Station, Antarctica. PhD thesis, University of Tasmania.

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Abstract

Marine benthic communities, including meiofauna, have commonly been used as a focus
of monitoring programs and of research into the effects of human activities in the marine
environment. In Antarctica, benthic communities have been shown to be good indicators
of human impacts, however, there is very limited information on Antarctic meiofaunal
communities and how they may respond to anthropogenic disturbances. The main types
of contamination present in marine sediments around Antarctic stations are metals and
hydrocarbons.
A survey of sediment meiofaunal communities was done at Casey Station, Antarctica,
with sampling at a range of spatial scales, from 10 meters to kilometers, to determine the
spatial patterns of community composition and abundance. This included a comparison of
control and disturbed areas (adjacent to old waste disposal sites). An MDS of all 47
samples supported by one way ANOSIM (Global R= 0.955, P< 0.001) showed the
variation within locations was less than the variation between locations (kms) and
significantly different between control and polluted locations. From the total meiofauna,
a higher percentage of nematodes, by comparison to harpacticoid copepods in both
controlled (nematode, 94.8%: harpacticoid copepods, 5.2%) and disturbed locations
(nematode, 95.4%: harpacticoid copepods, 4.6%).
Multivariate biological (meiofaunal communities) and environmental datasets were
examined to determine whether there were any correlations between patterns of community composition and environmental variables. The analysis suggested that the
most influential variables on the community pattern were metals of anthropogenic origin
such as tin, lead, iron, copper, and zinc but also metals that probably relate to local
differences in mineralogy such as silver, barium, uranium and arsenic. Grain size
parameters were found to have a much lower capacity to explain differences in
meiofaunal communities, although there did appear to be some influence.
An experiment was setup in which four different hydrocarbons (SAB diesel fuel, and
clean, used and biodegradable lubricant oils) were added to defaunated marine sediments
and deployed in trays in a sheltered marine bay. The communities colonizing the
sediments were monitored for up to five years. The effects of hydrocarbon contamination
on meiofaunal communities were different for each type of hydrocarbon. The Control and
Biodegradable treatments had the most similar meiofaunal communities at all sampling
times. Effects of hydrocarbon treatments were still evident after five years. Results also
suggest that changes in nematode composition are ideal for long term pollution
monitoring. By comparison, copepods appeared to be less sensitive to hydrocarbon
pollution. Long-term monitoring is essential to understand the true extent to which
lubricants impact the community structure.

Item Type: Thesis (PhD)
Copyright Holders: The Author
Copyright Information:

Copyright © 2011 the Author

Date Deposited: 19 Sep 2011 01:11
Last Modified: 11 Mar 2016 05:53
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