11th ICRS Abstract book - Nova Southeastern University
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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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12-5 The Contribution Of Heterotrophy To Recovery From Bleaching in A Cnidarian- Algal Symbiosis Cameron JOHNSON* 1 , Tamar GOULET 1 1 Biology, University of Mississippi, University, MS When elevated sea-surface temperatures cause the decoupling of cnidarian-algal symbioses, leading to reductions in the densities of the host’s autotrophic endosymbionts, some species of hosts will compensate by increasing heterotrophic feeding. In this study, we experimentally bleached the symbiotic sea anemone Aiptasia pallida, and then either starved (S) or fed (F) them during a 5 week period in order to see what effect heterotrophy may have on recovery rates. In each of three repeated factorial experiments (bleaching x feeding), half of the anemones were bleached (B) by elevating the temperatures from 25°C to 32°C for one week (week 0), while non-bleached anemones (NB) remained at 25°C. At the beginning of week 1, the bleached anemones were returned to their normal temperature (25°C), and both B and NB anemones were evenly divided among 2 additional treatments; starvation (SB and SNB), and fed (FB and FNB). Zooxanthella densities were monitored using photographic analysis of reflected spectra, which was calibrated with traditional bio-assays. Over the five week recovery period, zooxanthella densities had increased in the SNB, SB and FB treatments, while the zooxanthella densities in the FNB treatment remained constant. FB anemones had higher recovery rates than SB anemones (P=0.0044). Additionally, SNB anemones had significantly increased their zooxanthella densities (P=0.0331). These results suggest heterotrophy may play an important role in the reestablishment of endosymbiont populations after a bleaching event. Monitoring availability of plankton on a given reef may therefore be another important factor in determining reef recovery from a bleaching event. 12-6 Bleaching Effects On Scleractinian Coral Reproduction And Lipids Stores On The Great Barrier Reef, Australia Devin TU* 1 , Selina WARD 1 1 Centre for Marine Studies, University of Queensland, Brisbane, Australia This study investigated if bleaching reduced coral fecundity and lipids in the Great Barrier Reef. A secondary objective was to monitor the recovery rate of different coral species by using fecundity and percentage of lipid tissue in coral as a biological indicator. In addition, the study compared the severity of conditions in 1998 to the 2006 bleaching periods on the reef-flat, based on temperature and weather data. Many studies on coral bleaching focused on the 1998 bleaching event, which was considered the most severe event on the Great Barrier Reef (GBR) in that century (Hoegh-Guldberg 1999, NOAA 1998, ICRS 1998). Few have studied the effects of the 2006 bleaching event that took place in the southern Great Barrier Reef, Australia. Results demonstrate bleaching may not always impact negatively on the physiology of Acropora corals. Because of high variability of samples, there were no obvious differences in fecundity between bleached and unbleached Acropora aspera and Acropora millepore colonies based on percentage of reproductive polyps, and egg size and egg number per polyps. We hypothesize that there were no significant differences in lipid content between bleached and healthy corals in several species, however complete results were not available at the time of this submission. Bleached corals may have recovered before reproductive development. Basic in situ data suggests that summer 2006 conditions had abnormally high SSTs and light, but were not as elevated as 1998 at Heron Island, Australia. Potentially, zooxanthellae loss in bleached coral was not significant enough to reduce reproduction and lipids in Acropora species. This suggests that 2006 bleaching event, unlike pervious events, did not have a major impact on corals. Future research anticipates examining changes in chlorophyll a and zooxanthellae densities to identify the relationship between the severity of bleaching and the physiological impact on corals. Oral Mini-Symposium 12: Reef Resilience 12-8 Thailand’s Coral Reefs Show Resilience in The Face Of Repeated Natural Stressors Niphon PHONGSUWAN 1 , Anchalee CHANKONG 2 , Ronawon BOONPRAKOB 2 , Chaimongkol YAMARUNPATTHANA 1 , Sathika PAOKANTA 1 , Niphon PHONGSUWAN* 1 1 Marine and Coastal Resources, Phuket Marine Biological Center, Phuket, Thailand, 2 Marine and Coastal Resources, Eastern Marine and Coastal Resources Research Center, Rayong, Thailand Thailand’s coral reefs in the Andaman Sea and Gulf of Thailand have been repeatedly affected by both man-made and natural stressors over the last 20 years and yet have demonstrated considerable resilience, in particular to natural perturbations. Natural stressors have included Acanthaster infestations on the Andaman Sea coast in the mid 1980s; monsoon storms in 1986; elevated sea water temperatures which led to extensive coral bleaching in 1991 and 1995 in the Andaman Sea and in 1998 in the Gulf of Thailand; sea-level depression in 1997-98 and the tsunami of 2004, both of which only affected reefs in the Andaman Sea. Repeated monitoring of reefs in the periods 1988-1989; 1995-1998, in 2002 and again during 2006-2007 has revealed remarkable recovery at sites affected by major bleaching in 1991 and 1995 with virtually no impacts of minor localised bleaching noted at some sites in 2003, 2005 and 2007. The tsunami of 2004 had a very limited effect on coral reefs of the Andaman Sea and where damage occurred recovery is well underway at several locations. Such resilience appears to be restricted to sites affected only by natural perturbations since many shallow reefs near the mainland, which are chronically affected by siltation from land development, show little recovery. 12-9 Reefs, Resilience, And Refuges - Theoretical Considerations And Real-Life Examples Bernhard RIEGL* 1 , Samuel PURKIS 1 1 National Coral Reef Institute, Nova Southeastern University, Dania, FL If global changes impact reefs relatively uniformly, reefs with viable population dynamics will be resilient but some, and maybe eventually all, corals may be forced into refuges. Resilience or refuge character can be rooted in a more clement environment, adaptation to a harsh environment, or readjustments of population (community) dynamics caused by modified mortality-, survival- and recruitment-characteristics among species. Since many “traditional reefal settings” (tropical reef crests and slopes) seem to be degrading, one may search for sustainable dynamics in different habitats such as upwelling areas, deep reefs, or non-reefs. While these habitats may harbor less species or individuals, their population dynamics may be more advantageous. Even if the environments appear less suitable and the communities depauperate, a positive net population growth identifies potential refuges. Also, pulse-instability within dominance hierarchies may promote, or be a sign of, resilience. Opportunistic species may be naturally prone to large swings in abundance and find refuge in meta-populations that allow easy expansion or restriction of range. These species may adapt to only temporarily dominate communities of more resilient species. Their adaptation to changed environments may be less likely, since their reaction to stress would be population restriction and relocation into other, presumably more favorable, habitats. Temporary local absence would be part of survival strategy. Thus monitoring and assessment programs that primarily focus on coral cover, and not the underlying dynamics, may misunderstand resilience or refuge value of a habitat – since the present abundances are variable and may be misleading. Stochasticity of timing and distribution of impacts may allow apparently rich, but increasingly maladapted communities to persist, and lead to false conclusions regarding the nature of resilience or refuge. The presently richest areas may not be those with highest survivability. We use examples from all oceans to illustrate our point. 101

12-10 Tolerance, Refuge And Recovery Of Coral Communities To Thermal Bleaching David SUGGETT* 1 , David SMITH 1 , Nat SPRING 2 , Michelle ETIENNE 3 1 Biological Sciences, University of Essex, Colchester, United Kingdom, 2 Earthwatch Institute (Europe), Oxford, United Kingdom, 3 Seychelles Centre for Marine Research and Technology, Victoria, Seychelles Long term viability of coral communities is dictated by their ability to withstand environmental change, such as periods of elevated temperature. Three “mechanisms” exist by which reefs may survive such change: (1) physiological tolerance, (2) geographical retreat (refuge), and (3) repopulation and growth (recovery) once ambient conditions return. Here we report these “mechanisms” in operation by corals and coral communities exposed to thermally-induced bleaching conditions in the Seychelles. During the 1998 El Niño event, sea surface temperatures (SSTs) around the Seychelles persisted above 32°C and more than 75% of all reefs bleached. Since then, SSTs have not exceeded 32°C potentially allowing reefs to recover unchecked from repeat exposure. We performed extensive surveys of the size frequency distribution of species-specific colonies and observed that certain species survived the 1998 event whilst other species did not but have rapidly recruited into the system post 1998. Laboratory experiments confirmed that these different species-groups exhibited alternative physiological properties: Older established corals were most tolerant to periods of elevated temperature, as characterised by minor ‘downregulation’ of photosynthesis, and exhibited a greater metabolic potential for recovery (higher heterotrophy: autotrophy). Consequently, physiological properties of key coral species determined the current community structure post 1998. Turbid lagoons containing large colonies of susceptible species were identified, suggesting that these species survived 1998 by recruiting into ‘sub-optimal’ habitats and thus buffered against the elevated temperatures. Our results demonstrate that community structure analysis can be an important tool in identifying the ability of species to withstand environmental variability. Furthermore, that corals will survive climatic events and possible climate change by utilising various “mechanisms”. 12-11 Defining And Utilizing Indicators Of Reef Resilience in The Red Sea And Arabian Gulf Ameer ABDULLA* 1 , David OBURA 2 1 Marine Biodiversity and Conservation Science, IUCN Global Marine Program, malaga, Spain, 2 CORDIO, Mombasa, Kenya Defining and utilizing reef resilience indicators in the Red Sea and Arabian Gulf Red sea and Arabian Gulf coral reefs are characterized by high endemism and a naturally high tolerance to extreme environmental conditions such as high salinity, turbidity, and temperatures. These characteristics may indicate particularly high resilience to impacts associated with Climate Change, a feature of global importance. Consequently, Red Sea and Arabian Gulf sites were surveyed for resilience characteristics in 2007 and 2008. Forty nine resilience factors were identified for the two seas and their relative importance are compared to similar studies and indices developed for the Indian Ocean and Indopacific. These factors were used to identify key ecological areas of high resilience that were undamaged by particularly high regional SSTs in 1998, 1999, and 2001 – 2003 and that are priority areas for conservation. An aggregate of these factors and their relative weighting may prove useful in identifying other global reef sites of particularly high resilience and conservation importance. Oral Mini-Symposium 12: Reef Resilience 12-12 Reef Resilience and Change 1998-2007, Alphonse Atoll, Seychelles Annelise HAGAN* 1 , Tom SPENCER 1 1 Cambridge Coastal Research Unit, Department of Geography, University of Cambridge, Cambridge, United Kingdom Alphonse Atoll, southern Seychelles (7o01’S; 52o44’E), a small (11.28 km2) atoll with minimal anthropogenic influences, was severely impacted by the Indian Ocean warming event of 1997-1998. Quantitative measurements of benthic cover commenced at this location at the peak of the warming (April 1998), establishing bleaching impacts and allowing estimation of pre-bleaching cover characteristics. Underwater videography surveys of fixed transect lines were made in 2001/02, 2003, 2005 and 2007, providing quantitative information on the changing cover characteristics of 10 benthic classes. Immediately post-bleaching, the scleractinian community was dominated by few genera, particularly Porites, which survived the bleaching event, and Pocillopora and Acropora, which rapidly re-colonised bare surfaces, including dead coral skeletons. Lagoon corals and many shallow water corals, presumably acclimatised to warmer water conditions, were resilient to the 1998 thermal stress and may have seeded local coral recovery. In December 2006, wave fields associated with the passage of Cyclone Bondo resulted in transport of Porites colonies and large blocks of reef framework onto reef-flats, loss of post-bleaching coral recruits and increased macroalgal cover on the forereef slope. There is now a marked difference in reef health between the west and east fore-reef slope, despite a separation of only 2 km. This location provides one of the most detailed longterm (> 9 yrs) records of post-bleaching reef dynamics in the Western Indian Ocean. It demonstrates i) the interaction between, and subsequent recovery from, both physiological and physical disturbances and ii) varying resilience by atoll environment (fore-reef slope, reef crest, lagoon). Surveys 1998-2007 have shown changing relative proportions of scleractinian and macroalgal communities but no clear ‘phase-shift’ from a hard to a soft dominated reef community. 12-13 The Effects Of Habitat On Coral Resistance And Resilience To Bleaching Gabriel GRIMSDITCH* 1,2 , Nassir AMIYO 3 , Joseph KILONZO 4 1 IUCN Global Marine Programme, Mombasa, Kenya, 2 Cordio East Africa, Mombasa, Kenya, 3 Kenya Wildlife Service, Mombasa, Kenya, 4 Kenya Marine and Fisheries Research Institute, Mombasa, Kenya This study examines the bleaching responses of scleractinian corals at four sites in Kenya (Kanamai, Vipingo, Mombasa Marine Park and Nyali) representing two distinct lagoon habitats (relatively shallow and relatively deep). Bleaching responses were monitored for the general coral community and zooxanthella densities and chlorophyll levels were monitored for target species (Pocillopora damicornis, Porites lutea and Porites cylindrica) during a non-bleaching year (2006) and a year of mild bleaching (2007). The objective of this study is to determine whether corals in different habitats display varying resistance and resilience to bleaching stress and to indicate which environmental characteristics are responsible for the variation in response. Considerable differences in bleaching responses between shallower and deeper lagoon sites were observed, with shallower sites Kanamai and Vipingo exhibiting much lower bleaching and paling incidence than deeper sites Nyali and Mombasa Marine Park. These shallower lagoons display much more fluctuating thermal and light environments than the deeper sites, with higher maximums, lower minimums, higher standard deviations and higher diel variation. These results suggest that corals in the shallower lagoons have acclimatized and/or adapted to the fluctuating environmental conditions they endure on a daily basis and have become more resistant to bleaching stress. Furthermore, in deeper sites that did exhibit significant bleaching (Mombasa Marine Park and Nyali), it was found that coral recovery occurred more quickly in the protected area compared to the non-protected area. 102

12-10<br />

Tolerance, Refuge And Recovery Of Coral Communities To Thermal Bleaching<br />

David SUGGETT* 1 , David SMITH 1 , Nat SPRING 2 , Michelle ETIENNE 3<br />

1 Biological Sciences, <strong>University</strong> of Essex, Colchester, United Kingdom, 2 Earthwatch<br />

Institute (Europe), Oxford, United Kingdom, 3 Seychelles Centre for Marine Research and<br />

Technology, Victoria, Seychelles<br />

Long term viability of coral communities is dictated by their ability to withstand<br />

environmental change, such as periods of elevated temperature. Three “mechanisms”<br />

exist by which reefs may survive such change: (1) physiological tolerance, (2)<br />

geographical retreat (refuge), and (3) repopulation and growth (recovery) once ambient<br />

conditions return. Here we report these “mechanisms” in operation by corals and coral<br />

communities exposed to thermally-induced bleaching conditions in the Seychelles.<br />

During the 1998 El Niño event, sea surface temperatures (SSTs) around the Seychelles<br />

persisted above 32°C and more than 75% of all reefs bleached. Since then, SSTs have not<br />

exceeded 32°C potentially allowing reefs to recover unchecked from repeat exposure. We<br />

performed extensive surveys of the size frequency distribution of species-specific<br />

colonies and observed that certain species survived the 1998 event whilst other species<br />

did not but have rapidly recruited into the system post 1998. Laboratory experiments<br />

confirmed that these different species-groups exhibited alternative physiological<br />

properties: Older established corals were most tolerant to periods of elevated temperature,<br />

as characterised by minor ‘downregulation’ of photosynthesis, and exhibited a greater<br />

metabolic potential for recovery (higher heterotrophy: autotrophy). Consequently,<br />

physiological properties of key coral species determined the current community structure<br />

post 1998. Turbid lagoons containing large colonies of susceptible species were<br />

identified, suggesting that these species survived 1998 by recruiting into ‘sub-optimal’<br />

habitats and thus buffered against the elevated temperatures. Our results demonstrate that<br />

community structure analysis can be an important tool in identifying the ability of species<br />

to withstand environmental variability. Furthermore, that corals will survive climatic<br />

events and possible climate change by utilising various “mechanisms”.<br />

12-11<br />

Defining And Utilizing Indicators Of Reef Resilience in The Red Sea And Arabian<br />

Gulf<br />

Ameer ABDULLA* 1 , David OBURA 2<br />

1 Marine Biodiversity and Conservation Science, IUCN Global Marine Program, malaga,<br />

Spain, 2 CORDIO, Mombasa, Kenya<br />

Defining and utilizing reef resilience indicators in the Red Sea and Arabian Gulf<br />

Red sea and Arabian Gulf coral reefs are characterized by high endemism and a naturally<br />

high tolerance to extreme environmental conditions such as high salinity, turbidity, and<br />

temperatures. These characteristics may indicate particularly high resilience to impacts<br />

associated with Climate Change, a feature of global importance. Consequently, Red Sea<br />

and Arabian Gulf sites were surveyed for resilience characteristics in 2007 and 2008.<br />

Forty nine resilience factors were identified for the two seas and their relative importance<br />

are compared to similar studies and indices developed for the Indian Ocean and Indopacific.<br />

These factors were used to identify key ecological areas of high resilience that<br />

were undamaged by particularly high regional SSTs in 1998, 1999, and 2001 – 2003 and<br />

that are priority areas for conservation. An aggregate of these factors and their relative<br />

weighting may prove useful in identifying other global reef sites of particularly high<br />

resilience and conservation importance.<br />

Oral Mini-Symposium 12: Reef Resilience<br />

12-12<br />

Reef Resilience and Change 1998-2007, Alphonse Atoll, Seychelles<br />

Annelise HAGAN* 1 , Tom SPENCER 1<br />

1 Cambridge Coastal Research Unit, Department of Geography, <strong>University</strong> of Cambridge,<br />

Cambridge, United Kingdom<br />

Alphonse Atoll, southern Seychelles (7o01’S; 52o44’E), a small (11.28 km2) atoll with<br />

minimal anthropogenic influences, was severely impacted by the Indian Ocean warming event<br />

of 1997-1998. Quantitative measurements of benthic cover commenced at this location at the<br />

peak of the warming (April 1998), establishing bleaching impacts and allowing estimation of<br />

pre-bleaching cover characteristics. Underwater videography surveys of fixed transect lines<br />

were made in 2001/02, 2003, 2005 and 2007, providing quantitative information on the<br />

changing cover characteristics of 10 benthic classes. Immediately post-bleaching, the<br />

scleractinian community was dominated by few genera, particularly Porites, which survived the<br />

bleaching event, and Pocillopora and Acropora, which rapidly re-colonised bare surfaces,<br />

including dead coral skeletons. Lagoon corals and many shallow water corals, presumably<br />

acclimatised to warmer water conditions, were resilient to the 1998 thermal stress and may have<br />

seeded local coral recovery. In December 2006, wave fields associated with the passage of<br />

Cyclone Bondo resulted in transport of Porites colonies and large blocks of reef framework<br />

onto reef-flats, loss of post-bleaching coral recruits and increased macroalgal cover on the forereef<br />

slope. There is now a marked difference in reef health between the west and east fore-reef<br />

slope, despite a separation of only 2 km. This location provides one of the most detailed longterm<br />

(> 9 yrs) records of post-bleaching reef dynamics in the Western Indian Ocean. It<br />

demonstrates i) the interaction between, and subsequent recovery from, both physiological and<br />

physical disturbances and ii) varying resilience by atoll environment (fore-reef slope, reef crest,<br />

lagoon). Surveys 1998-2007 have shown changing relative proportions of scleractinian and<br />

macroalgal communities but no clear ‘phase-shift’ from a hard to a soft dominated reef<br />

community.<br />

12-13<br />

The Effects Of Habitat On Coral Resistance And Resilience To Bleaching<br />

Gabriel GRIMSDITCH* 1,2 , Nassir AMIYO 3 , Joseph KILONZO 4<br />

1 IUCN Global Marine Programme, Mombasa, Kenya, 2 Cordio East Africa, Mombasa, Kenya,<br />

3 Kenya Wildlife Service, Mombasa, Kenya, 4 Kenya Marine and Fisheries Research Institute,<br />

Mombasa, Kenya<br />

This study examines the bleaching responses of scleractinian corals at four sites in Kenya<br />

(Kanamai, Vipingo, Mombasa Marine Park and Nyali) representing two distinct lagoon habitats<br />

(relatively shallow and relatively deep). Bleaching responses were monitored for the general<br />

coral community and zooxanthella densities and chlorophyll levels were monitored for target<br />

species (Pocillopora damicornis, Porites lutea and Porites cylindrica) during a non-bleaching<br />

year (2006) and a year of mild bleaching (2007). The objective of this study is to determine<br />

whether corals in different habitats display varying resistance and resilience to bleaching stress<br />

and to indicate which environmental characteristics are responsible for the variation in response.<br />

Considerable differences in bleaching responses between shallower and deeper lagoon sites<br />

were observed, with shallower sites Kanamai and Vipingo exhibiting much lower bleaching and<br />

paling incidence than deeper sites Nyali and Mombasa Marine Park. These shallower lagoons<br />

display much more fluctuating thermal and light environments than the deeper sites, with higher<br />

maximums, lower minimums, higher standard deviations and higher diel variation. These<br />

results suggest that corals in the shallower lagoons have acclimatized and/or adapted to the<br />

fluctuating environmental conditions they endure on a daily basis and have become more<br />

resistant to bleaching stress. Furthermore, in deeper sites that did exhibit significant bleaching<br />

(Mombasa Marine Park and Nyali), it was found that coral recovery occurred more quickly in<br />

the protected area compared to the non-protected area.<br />

102

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