11th ICRS Abstract book - Nova Southeastern University
11th ICRS Abstract book - Nova Southeastern University
11th ICRS Abstract book - Nova Southeastern University
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Oral Mini-Symposium 25: Predicting Reef Futures in the Context of Climate Change<br />
25-17<br />
Climate Change And Reef Development in The Tropical Eastern Pacific<br />
Richard ARONSON* 1 , Ian MACINTYRE 2 , Steven VOLLMER 3 , Jennifer HOBBS 4 ,<br />
Anke MOESINGER 1<br />
1 Dauphin Island Sea Lab, Dauphin Island, AL, 2 Department of Paleobiology,<br />
Smithsonian Institution, Washington, DC, 3 Marine Sciences Center, Northeastern<br />
<strong>University</strong>, Nahant, MA, 4 School of Marine and Atmospheric Science, Stony Brook<br />
<strong>University</strong>, Stony Brook, NY<br />
Understanding how biotic turnover controls the development of coral reefs will be critical<br />
to projecting their future in a rapidly changing world. How well reefs keep up with rising<br />
sea level will determine the extent to which they protect adjacent land masses from<br />
coastal erosion. In the tropical eastern Pacific, populations of Pocillopora damicornis, the<br />
dominant constructor of reef framework, were bleached on a regional scale by the 1982–<br />
83 El Niño event. Subsequent coral mortality and bioerosion suggested that centennialscale<br />
recurrences of extreme thermal anomalies associated with the El Niño–Southern<br />
Oscillation have slowed accretion rates of eastern Pacific reefs by killing Pocillopora<br />
episodically. Off the Pacific coast of Panamá, Pocillopora recovered rapidly after 1983 in<br />
some places but not in others. Where it did not recover, the Pocillopora rubble was<br />
colonized by another coral species, Psammocora stellata, which is not a frameworkbuilder.<br />
Coring studies in the Gulf of Panamá showed that Pocillopora kills and shifts to<br />
Psammocora occurred episodically over the past 6000–7000 years; however, Pocillopora<br />
growth was suppressed for centuries to millennia, depressing vertical reef accretion for<br />
intervals far longer than the return time of strong El Niño events. These protracted<br />
intervals of suppressed coral growth can be used to parameterize models of reef accretion<br />
under scenarios of biannual to annual coral bleaching, predicted to commence in the next<br />
several decades. Oceanic acidification will further inhibit reef accretion, especially in the<br />
tropical eastern Pacific where upwelled waters already expose Pocillopora populations to<br />
elevated concentrations of dissolved carbon dioxide.<br />
25-18<br />
Fragile Reefs Of The Eastern Pacific: A Model For Reefs in A High Co2 World<br />
Derek MANZELLO* 1 , Joanie KLEYPAS 2,3 , David BUDD 4 , Mark EAKIN 5<br />
1 Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School,<br />
<strong>University</strong> of Miami, Miami, FL, 2 Institute for the Study of Society and Environment,<br />
National Center for Atmospheric Research, Boulder, CO, 3 Institute for the Study of<br />
Society and Environment, National Center for Atmospheric Research, Boulder, 4 Dept. of<br />
Geological Sciences, Univ. of Colorado, Boulder, CO, 5 Coral Reef Watch, NOAA<br />
NESDIS, Silver Spring, MD<br />
Ocean acidification describes the progressive, global reduction in seawater pH that is<br />
currently underway due to the oceanic uptake of increasing atmospheric CO2.<br />
Acidification is expected to reduce coral reef calcification and increase reef dissolution,<br />
and the relative rates of change will likely be a function of pCO2 (the partial pressure of<br />
CO2) in seawater, which is directly proportional to pCO2 in the atmosphere. Little is<br />
known about the effects of acidification on syndepositional processes that affect the<br />
persistence and preservation of carbonates (i.e., early marine diagenesis). Newly<br />
analyzed samples agree with previous studies showing that only trace amounts of<br />
inorganic cements occur in modern day coral reefs that exist naturally under low ambient<br />
pH in the eastern Tropical Pacific (ETP). The variation in cement abundance and rates of<br />
bioerosion between sites in Panamá and Galápagos appears to be related to differences in<br />
the saturation state of CaCO3 (Ω); suggesting a link between Ω, inorganic cementation<br />
and coral reef development in the ETP. ETP reefs may thus provide a real-world model<br />
of coral reef growth in low Ω waters and provide insights into the role of decreasing Ω on<br />
reefs beyond the prediction of reduced CaCO3 production.<br />
25-19<br />
Phase Shifts in Coral Reefs – Comparative Investigation Of Corals And Benthic Algae As<br />
Ecosystem Engineers<br />
Christian WILD* 1 , Andreas HAAS 1 , Malik NAUMANN 1 , Christoph MAYR 2<br />
1 Coral Reef Ecology (CORE) Work Group,GeoBio-Center, Ludwig-Maximilians-Universität<br />
München, München, Germany, 2 GeoBio-Center, Ludwig-Maximilians-Universität München,<br />
München, Germany<br />
Global climate change and direct anthropogenic stress factors do strongly affect the benthic<br />
community structure in coral reefs. It is reported from the literature that hermatypic corals are<br />
gradually replaced by benthic micro- and macro-algae at many reef locations around the world,<br />
a process which is commonly referred to as phase shift. Recent research showed that hermatypic<br />
corals via the release of organic matter and concomitant effects on cycles of matter can act as<br />
engineers of reef ecosystems. There are strong indications that reef associated benthic algae do<br />
also affect reef ecosystem functioning via organic matter release, but all relevant information is<br />
lacking. To gain a better understanding of the biogeochemical consequences such phase shifts<br />
from corals to algae entail, a series of comparative studies with hermatypic corals and benthic<br />
algae were conducted in reefs of the Northern Red Sea during four seasonal expeditions in<br />
2006-2008. These investigations primarily focused on the quantity and quality of the organic<br />
matter released by both groups of organisms involving dissolved organic carbon (DOC),<br />
particulate organic carbon (POC) and particulate nitrogen (PN). Supplementary mass<br />
spectrometric analyses were conducted in order to analyse stable isotope signatures of coral- or<br />
algae-derived organic matter. Finally, planktonic and benthic degradation of the respective<br />
organic matter were investigated in the field using bottle incubation experiments and stirred<br />
benthic chambers, respectively. Our data show clear differences between organic matter release<br />
by benthic reef algae or corals for most of the measured parameters, thus, suggest a massive<br />
influence of the described phase shifts onto biogeochemical cycles and processes in warm water<br />
coral reefs.<br />
25-20<br />
Long-Term, Regional-Scale Patterns in Caribbean Coral Bleaching Responses<br />
Allison L. PERRY* 1,2 , Isabelle M. CÔTÉ 3 , John D. REYNOLDS 3 , Andrew R.<br />
WATKINSON 4,5<br />
1 WorldFish Center, Bayan Lepas, Penang, Malaysia, 2 School of Biological Sciences, <strong>University</strong><br />
of East Anglia, Norwich, United Kingdom, 3 Department of Biological Sciences, Simon Fraser<br />
<strong>University</strong>, Burnaby, BC, Canada, 4 School of Environmental Sciences, <strong>University</strong> of East<br />
Anglia, Norwich, United Kingdom, 5 Tyndall Centre for Climate Change Research, Norwich,<br />
United Kingdom<br />
Coral bleaching is one of the most serious and immediate ecological impacts of climate change,<br />
with bleaching events increasing in frequency, severity and extent with rising sea surface<br />
temperatures (SSTs). Given the geographically widespread nature of this phenomenon, there is<br />
a need to understand patterns and drivers of bleaching over multiple spatial and temporal scales.<br />
We take a regional-scale approach, and examine long-term trends in the occurrence of coral<br />
bleaching in the Caribbean region, and in the SST anomalies associated with bleaching. Using<br />
data over a 24-year period, we assess whether corals may be adjusting to rising temperatures,<br />
and examine the regional-scale relationship between the geographic extent of bleaching and<br />
rising SST anomalies. At both local and regional scales, there is little evidence to support the<br />
possibility that Caribbean reefs are keeping pace with rising sea temperatures, while the<br />
geographic extent of bleaching in the region is accelerating with rising sea temperatures even<br />
more rapidly than previously known. In combination, our results emphasise the particular<br />
vulnerability of reefs to climatic warming.<br />
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