Modelling Environmental Impacts on Marine Ecosystems and Coral Reefs
Kwiatkowski, Lester
Date: 23 December 2013
Publisher
University of Exeter
Degree Title
PhD in Mathematics
Abstract
Coral reefs are the iconic ecosystem of tropical seas and yet they are under increasing
pressure as a result of multiple climatic stressors. This thesis uses observations
and models to further understanding of environmental impacts on coral reefs. In
particular it examines the impact of rising Sea Surface Temperature (SST) and
ocean ...
Coral reefs are the iconic ecosystem of tropical seas and yet they are under increasing
pressure as a result of multiple climatic stressors. This thesis uses observations
and models to further understanding of environmental impacts on coral reefs. In
particular it examines the impact of rising Sea Surface Temperature (SST) and
ocean acidification on coral growth and the frequency of coral bleaching events.
UK ocean biogeochemical models are assessed for implementation in the next UK
Earth System Model. This analysis finds little evidence that more complex ocean
biogeochemical models provide better simulations of large scale biogeochemical
features. An established wavelet-based spatial comparison technique is used to
analyse the spatial scales that Earth System Models can skillfully simulate patterns
of SSTs. It is shown that in coral regions, current models cannot skilfully
simulate patterns of historical SST anomalies at sub-regional (<32◦) scales. These
findings are used in combination with SST and aragonite saturation state outputs
from Earth System Models to show that historical Caribbean coral growth has
been influenced by anthropogenic aerosol emissions over the 20th Century. Earth
System Model outputs are also used to make projections of global coral bleaching
throughout the 21st Century. It is shown that under even the most extreme conventional
mitigation scenarios the majority of the world’s coral reefs are projected
to experience levels of thermal stress induced bleaching that cause reef degradation
throughout the 21st Century. Geoengeering scenarios involving the injection of SO2
into the stratosphere can reduce the projected thermal stress on coral reefs relative
to conventional mitigation scenarios but such benefits are shown to be highly
dependent on the sensitivity of coral bleaching thresholds to ocean acidification.
Doctoral Theses
Doctoral College
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