Although
the natural absorption of CO2 by the world’s oceans help mitigate climate
effects, the resulting decrease in pH causes ocean acidification which can have
negative consequences for much of the marine life, specifically calcifiers such
as corals and mollusks that construct their shells and skeletons from calcium
carbonate.
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To study
the effects of ocean acidification on deep-sea organisms, a team of researchers
at the University of Bristol and Yale University used Synchrotron Radiation
X-ray Tomographic Microscopy (SRXTM) of the TOMCAT beamline at the Paul Scherer
Institute in Switzerland. This technology is capable of generating high
resolution, 3D images of deep-sea benthic foraminifera, unicellular organisms that
make microscopic fossil shells.
About
55.5 million years ago, the earth underwent a global warming of five degrees Celsius,
which caused severe ocean acidification, and widespread extinction of
microscopic organisms living on the deep-sea floor (foraminifera). By studying
the survivors of this extinction, unique insight was discovered from past
warming events that may resemble future consequences of fossil fuel CO2
emissions.
Research
shows that the calcifying organisms actually increased the thickness of their
shells during ocean acidification. Also organisms living buried within the
sediment were able to survive better than forms living on the sediment surface.
Dr Laura Foster, first author of the paper, and
post-doctoral researcher at the University of Bristol’s School of Earth Sciences,
explained: “We use state-of-the-art techniques to virtually section
foraminifera, and gain insight in their shell construction, duration of life
and mode of reproduction. We have much to learn about and from single-celled
organisms, which serve as monitoring organisms for deep-sea calcifiers in
general, and their response to past ocean acidification. They are a crucial
part of the huge deep-sea oceanic ecosystem, and understanding what happened to
them during acidification in the past is critical to improving projections on
the effects of future climate change.”
Dr Daniela Schmidt, a Royal Society Research Fellow at
Bristol’s School of Earth Sciences, added: “Short-term experiments cannot
provide information on ways in which organisms can acclimatise, adapt or evolve
in the long term. We used the geological record to examine the impact of
multiple stressors, such as changes in carbonate chemistry and temperature, to
provide information on how organisms adapt to large CO2 releases.”
The
research, by scientists from the University of Bristol (UK) and Yale University
(USA), is reported in this week’s early edition of the Proceedings of the National Academies of
Science.
Read more at the University of Bristol.
Coral image via Shutterstock.