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Australia: The Land Where Time Began |
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Northwest Australia – Evidence for Synchrony of Marine and Terrestrial
Ecosystems that is Driven by Climate
It is difficult to predict the effects of climate change for many marine
species as not much is known about their response to climate change in
the past. A variable that integrates multiple physical and biological
factors, the long-term chronologies of growth, have become available for
several marine taxa. These have allowed a search for synchrony in growth
that is driven by climate across multiple taxa and ecosystems,
identifying the key processes that drive biological responses on very
large spatial scales. Ong et al.
hypothesised that in northwest Australia, which is a region that is
predicted to be strongly influenced by climate change, the El
Niño-Southern Oscillation (ENSO) phenomenon would be an important factor
that influences the growth patterns of organisms in terrestrial as well
as marine environments. Ong et al.
analysed existing growth chronologies of the marine fish
Lutjanus argentimaculatus,
the coral
Porites spp. And the tree
Callitris columellaris
and they developed a new chronology for another marine fish,
Lethrinus nebulosus.
Evidence of ENSO-driven synchrony in growth among all 4 taxa at
interannual time scales, was shown by principal components analysis and
linear model selection, which was the first such result for the Southern
Hemisphere. The annual growth of trees, fishes and corals are all
influenced by rainfall, sea surface temperature and the salinities of
the surface water, which are linked to the ENSO system. The 4 taxa had
negative relationships with the Niño-4 index, which is a measure of ENSO
status, and during strong La Niña years, positive growth patterns
occurring. Ong et al. suggest
that it is implied by this finding that changes in the future in the
strength and frequency of ENSO events are likely to have major
consequences for marine and terrestrial taxa. Ong et
al. suggest that as a result
of the strong similarities in growth patterns of fish and trees, tree
ring chronologies may possibly be used, which cover a wider span of time
than fish, to increase understanding of historical and future responses
of fish populations to climate variation.
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |