11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 25: Predicting Reef Futures in the Context of Climate Change
25.1137
Effects Of Elevated Seawater Temperatures On The Development And
Survivorship Of Larvae Of The Eklhorn Coral acropora Palmata
Carly RANDALL* 1 , Alina SZMANT 1
1
Biology and Marine Biology, University of North Carolina Wilmington, Wilmington,
NC
Elevated seawater temperatures during the late summer and fall, followed by periods of
bleaching and increased susceptibility to disease, have led to a reduction in live coral
cover on coral reefs. Bleached corals have also been found to exhibit reduced
reproductive success. Both lower adult abundance and lower fecundity could result in a
reduced ability of these populations to recover. The effect of elevated seawater
temperatures on early life-stages of corals that reproduce during these warm times of year
also remains poorly studied. If elevated temperatures reduce survival and settlement of
coral larvae, the recovery of coral populations will be further impeded. Effects of
elevated temperature on the survivorship of the larvae of the broadcast spawning coral
Acropora palmata were studied experimentally. Larvae maintained at temperatures
only one degree above historic summer values (29.5-31 ºC) exhibited reduced
survivorship as compared to those maintained within the normal summer temperature
range (27-28 ºC). Larvae maintained at the control temperature, 27.5 ºC, exhibited a
cumulative average survivorship of 28.9 % over the 140 hour experiment whereas larvae
maintained at the elevated temperature of 31.5 ºC exhibited a significantly reduced
cumulative average survivorship of only 2.0 %. Intermediate survivorship of 10.9 % was
observed at the intermediate temperature of 29.3 ºC. However, in a preliminary
settlement trial, there was no significant difference among those larvae that survived to
this stage. These results show that the supply of coral larvae to Caribbean reefs is being
seriously reduced by global warming. Samples of embryos and larvae were fixed for
electron microscopy at various times during the course of temperature exposure and
processing of those samples is ongoing to examine the effects of elevated temperature on
the larval development.
25.1138
Coral Reef Monitoring In The Gilbert Group, Kiribati: Taking Into Account Longterm
Monitoring And Limited Resources
Taratau KIRATA* 1 , Toaea BEIATEUEA 1 , Tebaua SAPOLU 1 , Aaranteiti TEKIAU 1 ,
Dr. Simon DONNER 2,3
1 Fisheries Department, Ministry of Fisheries and Marine Resources Development,
Tarawa, Kiribati, 2 Geography Department, University of British Columbia, Vancouver,
BC, Canada, 3 Woodrow Wilson School of Public & International Affairs, Princeton
University, Princeton
The coral reefs of the western part of Kiribati (Gilbert Islands), a group of coral atolls
stretching from 3 ° N to 6 ° S in the Western Pacific, are subject to multiple stresses
including pollution (sewage), resources exploitation and coral bleaching. The increasing
local and global demand for fish and other marine resources may be affecting coral reef
health, resource availability and contributing to outbreaks of toxic fish poisoning. The
region is also exposed El Nino-related warm water anomalies that can cause mass coral
bleaching. There is a need for a long-term monitoring program that considers the limited
resources of the isolated islands and increasing threats from climate change.
Here we describe a new continuous monitoring program for the Gilbert group. The
protocol includes manta tows, PITs at 3m and 10m depth and random photo-quadrats at
selected islands; more detailed monitoring is conducted around the central atoll of
Tarawa due to easier access. Preliminary results show hard coral cover of 10-20% on the
outer reefs of South Tarawa, possibly due to population pressure and wave action; hard
coral cover is higher (25-40%) at similar depths around Butaratari and Abaiang.
Acropora sp. is surprisingly rare around Tarawa and Abaiang. There are a high number of
dead colonies of Pocillipora sp. at most sites, particularly around Butaritari, possibly
from coral bleaching in 2004. The results from ongoing monitoring could help the people
of Kiribati understand how to adapt to the rising pressure on marine resources, outbreaks
of fish poisoning and climate change.
25.1139
Effects of elevated pCO2 and temperature on calcification and photosynthesis of the
Mediterranean coral Cladocora caespitosa
Riccardo RODOLFO-METALPA* 1 , Sophie MARTIN 2 , Christine FERRIER-PAGÈS 3 , Jean-
Pierre GATTUSO 4
1Marine Biology and Ecology Research Centre, University of Plymouth, Plymouth, United
Kingdom, 2International Atomic Energy Agency, Monaco, Monaco, 3Centre Scientifique de
Monaco, Monaco, Monaco, 4CNRS-Centre National de la Recherche Scientifique,
Villefranche-sur-mer Cedex, France
Atmospheric CO2 partial pressure (pCO2) is expected to double by the end of the present
century, and will be accompanied by an increase in seawater temperature. Since pCO2 was
shown to decrease calcification rates in tropical corals, it might also affect temperate corals,
such as those living in the Mediterranean Sea. Colonies of the Mediterranean coral Cladocora
caespitosa were collected at ca. 30 m depth in the NW Mediterranean Sea and maintained under
normal and elevated temperature (T and T+3°C, respectively) and pCO2 (400 and 700 µatm,
respectively) levels, alone or in combination. Temperature (T = 13-22°C) and light (20-60 µmol
photons m-2 s-1) varied seasonally while pCO2 was kept constant. Rates of photosynthesis and
calcification, and symbiont parameters were measured during two short-term (one month)
experiments carried out in Summer 2006 and Winter 2007. Additionally, coral growth and the
effective quantum yields (∆F/Fm') were measured during a long-term (1 year) experiment.
A 3°C increase in temperature had some effects on coral physiological parameters, increasing
photosynthetic and respiration rates and decreasing ∆F/Fm', depending on the season.
Conversely, a doubling in pCO2, alone or in combination with elevated temperature, had no
significant effect on any of the parameters tested, either during the short or the long-term
experiment. In particular, no significant effect was found on calcification and growth rates. This
result seems different from tropical corals, in which rates of calcification decrease at elevated
pCO2. However, it is important to note that the corals used were collected at the deeper end of
their bathymetric range, were grown at low irradiance and were therefore likely light-limited. It
is critical to investigate the response of shallow-water colonies to elevated pCO2 to investigate
a potentially significant interaction between light, temperature and pCO2 to control the
metabolism of Mediterranean corals.
25.1140
Distribution of algal symbionts (Symbiodinium spp.) in reef corals along a latitudinal
gradient in Western Australia
Rachel SILVERSTEIN* 1 , Adrienne M. S. CORREA 2,3 , Andrew BAKER 1
1 Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Sciences,
University of Miami, Miami, FL, 2 Ecology, Evolution and Environmental Biology, Columbia
University, New York, NY, 3 Marine Biology and Fisheries, Rosenstiel School of Marine and
Atmospheric Sciences, University of Miami, Miami
Mutualisms involving dinoflagellate algae in the genus Symbiodinium metabolically support
reef-building corals, thereby underpinning the high levels of productivity characteristic of coral
reefs. High temperature-related “bleaching” events cause reef corals to lose their endosymbiotic
algae and, if prolonged, lead to coral mortality. However, corals may be able to recover from
bleaching and to acclimatize to climatic changes by shuffling between symbiont types with
varying environmental optima. The diversity of these symbiont types within scleractinian
corals is still being realized and appears to be geographically specific in many cases. To
document symbiont diversity in Western Australia, where little Symbiodinium research has
previously taken place, this study examined symbiotic algae within more than 30 coral hosts
sampled from five sites that span over 2500 km of coastline. Collection locations include the
sub-tropical Ningaloo Reef, which hosts high coral diversity, Rottnest Island and Dunsborough,
an extreme high latitude (~33°S) with respect to the range of reef corals. In order to study the
genetic diversity of Symbiodinium, the ITS-2 region of the nuclear ribosomal DNA was
amplified and sequenced. Resulting ITS-2 types were then compared to a database of known
Symbiodinium diversity and novel sequences were placed in an evolutionary context by
building phylogenetic trees and statistical parsimony networks. This study demonstrates
patterns of symbiont distributions in accordance with the prevailing environmental conditions
varying along a gradient of irradiance and temperature. Our data indicate that Western Australia
is a region of high symbiont diversity both between and within host coral species, with many
apparently unique symbiont types. This study both reconfirms ecological symbiont patterns
previously reported and shows some unexpected distributions.
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