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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Oral Mini-Symposium 19: Biogeochemical Cycles in Coral Reef Environments 19-9 A Role Of Organic Matter In Chemical Symbiosis At Coral Reef Yoshimi SUZUKI* 1 , Beatriz CASARETO 1 , Sylvain AGOSTINI 1 , M.F.M FARIOZ 1 , Kazuyo SHIROMA 1 , Loic CHARPY 2 1 Graduate School of Science and Tecnology, Shizuoka University, Shizuoka, Japan, 2 Cyanobacteria Lab., IRD, Marseille, France Bleaching of corals and damages of the symbiotic zooxanthellae are presently believed to result largely from elevated temperature of the seawater and the increase of UV radiation. Mild or moderate bleaching is commonly followed by recovery, but the long-term effects of high temperature of seawater will end in an irreversible bleaching and massive death of corals. Due to the impact of rising up seawater temperature, corals receive a strong stress, and as a result, corals release high amounts of organic matters (mucus) and ammonia. This means that organic matters in dissolved (DOM) and particulate (POM) forms might play an important role for the fate of corals and coral ecosystem, especially in the food web. The production of organic matters by corals can act as a mechanism for defence but also it is used in feeding for particles capture strategy. High amount of ammonia in the reefs surrounding waters can enhance the growth of pico-phytoplankton, which acts as main food source for benthic community. However organic matters may enhance the growth of certain bacteria, which are known to infect corals and induce bleaching and diseases. Therefore the understanding of organic matters dynamics is of extremely importance for the evaluation of coral health. In this paper, the behaviour of dissolved and particulate organic matters such as concentration, distribution and changes in its characteristics (composition such as amino acids, carbohydrate and molecular weight) at the field and during incubation experiments are reported. We discuss also the significance of chemical symbiosis in coral reef communities. 19-10 Stimulation Of Coral-Derived Organic Matter Release During Bleaching Wolfgang NIGGL* 1 , Martin GLAS 1 , Christoph MAYR 2 , Christian LAFORSCH 3 , Christian WILD 1 1 Coral Reef Ecology Work Group (CORE), GeoBio-Center, Ludwig-Maximilians- Universität München, Munich, Germany, 2 GeoBio-Center & Department of Earth and Environmental Science, Ludwig-Maximilians-Universität München, Munich, Germany, 3 Department Biology II, Ludwig-Maximilians-Universität München, Munich, Germany Corals continuously release mucoid exudates in order to clean their surfaces. But recent research also showed that this coral-derived organic matter acts as an energy carrier and particle trap, thus plays an important ecological role for recycling of matter and conservation of nutrients for the oligotrophic reef ecosystem. Some environmental stressors such as air exposure, high sediment loads and turbidity are known to increase mucus production. But although it is a common statement in the literature, scientific data verifying increased mucus release rates during temperature-induced bleaching events (loss of symbiotic zooxanthellae from the coral host) are lacking. This is critical as coral bleaching is the most extensive coral disease world-wide, and bleaching-induced changes in organic matter release potentially have far reaching consequences for reef functioning. In this study, we induced a bleaching event and determined release of particulate organic carbon (POC) and particulate nitrogen (PN) by corals. A new methodology involving several centrifugation steps was introduced in order to separate released zooxanthellae from the coral-derived organic matter. Microscopical counting revealed that at least 99 % of released zooxanthellae could be removed. Our results show that during bleaching on average 50 % more POC is released whereas PN release rates almost doubled compared to the unstressed controls. This is the first experimental evidence that coral bleaching has consequences for organic matter release and ensuing element cycles in tropical reef ecosystems. 19-11 Bacterial Degradability Of The Organic Matter Released From Symbiotic Coral Colonies Yasuaki TANAKA* 1 , Toshihiro MIYAJIMA 1 , Yu UMEZAWA 2 , Isao KOIKE 3 , Takeshi HAYASHIBARA 4 , Hiroshi OGAWA 1 1 The University of Tokyo, Tokyo, Japan, 2 Research Institute for Humanity and Nature, Kyoto, Japan, 3 University of the Ryukyus, Naha, Japan, 4 Seikai National Fisheries Research Institute, Ishigaki, Japan The organic matter released from corals is well known to be utilized by bacteria and stimulate the bacterial growth. However, degradability of the organic matter has not been investigated in a long-term perspective and therefore it is still not understood what % of the released organic matter can actually be mineralized by bacteria. To investigate the long-term degradability, the reef-building corals Acropora pulchra and Porites cylindrica were first incubated in a normal submerged condition or a stressful condition (air exposure), and released organic matter to the ambient seawater. After taking out of the corals, the incubation seawater containing organic matter was put under dark over 1 year to follow bacterial decomposition of dissolved and particulate organic matter (DOM and POM). The results showed that the concentrations of DOM and POM rapidly decreased within the first 1 week and the remaining organic matter was gradually decomposed much more slowly, suggesting that the coral-derived organic matter had two different fractions in bacterial degradability. The labile organic matter (L-OM) had turnover time of 3.2-9.1 d (average 6.2 d) for DOM and 5.6-9.1 d (average 7.4 d) for POM. The L-OM could be easily mineralized within or around the reef ecosystem. The stressful condition increased the ratio of degradable to bulk organic matter. On the other hand, a part of the coralderived organic matter was not mineralized even after 1 year, suggesting that it was very recalcitrant to bacterial decomposition. The corals might routinely release such refractory organic matter to the ambient seawater for defense against pathogens. 19-12 Uptake Of Dissolved Organic Matter By The Scleractinian Coral Stylophora Pistillata Renaud GROVER* 1 , Jean-François MAGUER 2 , Denis ALLEMAND 1 , Christine FERRIER- PAGÈS 1 1 Centre Scientifique de Monaco, Monaco, Monaco, 2 Laboratoire de Chimie Marine, Institut Universitaire Européen de la Mer, PLOUZANE, France In this work, we investigated the importance of dissolved free amino acids (DFAA) as an organic nitrogen source for the scleractinian coral Stylophora pistillata. For this purpose, 15Nenriched DFAAs were used and %15N enrichments were measured separately in both symbiotic zooxanthellae and animal tissue after incubation of the entire coral colonies at different DFAA concentrations and light levels. As previously observed for urea, which is another organic nitrogen source for corals, DFAA uptake is carrier mediated for concentrations below 3 µM and diffusive for higher concentrations. Our results showed that corals are well adapted to in situ DFAA concentrations, since they are able to take up DFAAs at very low concentrations (ca. 0.5 µM) and their Km, that represents the carrier affinity for the substrate was also very low. When normalized to skeletal surface area, uptake rates were ca. twice higher in the animal tissue than in the zooxanthellae and were enhanced by light exposure. The contribution of DFAA as a nitrogen source for tissue growth in the coral Stylophora Pistillata was compared to other nitrogen sources such as ammonia and nitrate for the inorganic part, as well as urea for the organic part. It ensues that inorganic sources constitute 75% of the daily nitrogen needs against 24% for the organic sources, and that all dissolved nitrogen sources can supply almost 100% of the nitrogen needed for tissue growth. 165

Oral Mini-Symposium 19: Biogeochemical Cycles in Coral Reef Environments 19-13 Water Quality Monitoring Along The Florida Reef Tract: Assessment Of Dissolved Organic Matter Sources And Compositional Variations Youhei YAMASHITA* 1 , Joseph BOYER 1 , Diane WILLIAMS 1 , Rudolf JAFFE 1 1 Southeast Environmental Research Center, Florida International University, Miami, FL The characterization of DOM can contribute to understanding its ecological roles in diverse aquatic environments. This carbon pool is highly reactive and influences ecosystem function through many biogeochemical reactions and is known to fuel the microbial loop, particularly in oligotrophic environments. Thus in addition to its quantity it is important to determine its source and characteristics (i.e. quality) in large scale and long term water quality monitoring programs. DOM in coastal regions is derived from a variety of sources, including autochthonous planktonic as well as allochthonous terrestrial and anthropogenic sources and its quality has been found to strongly depend on sources and physical and biological processes. This study reports on preliminary data on DOM quality along the Florida Keys reef tract. The concentration of dissolved organic carbon (TOC) and dissolved organic nitrogen (DON) in addition to optical properties of DOM were determined at over 100 field stations ranging from the upper Florida Keys to the Dry Tortugas National Park in the Gulf of Mexico on a quarterly schedule. DOM quality was determined through excitation emission matrix (EEM) fluorescence in combination with parallel factor analysis (PARAFAC). Results show that the DOM associated with the South Florida coral reef community is derived from a combination of sources including autochthonous microbial sources as well as terrestrial and anthropogenic sources, both from the Florida Keys as well as through water exchange with Florida Bay and the Florida Shelf. The spatial variability confirmed potential source assignments of the DOM. 19-14 Organic Matter Cycling in Tropical Coral Reef Ecosystems: The Role Of The Reef Framework And Its Biota, Dominated By Encrusting Sponges. Jasper M. DE GOEIJ* 1,2 , Joost W. VAN DAM 1,2 , Hubèrt EIJKELENBOOM 1,2 , Eric H.G. EPPING 3 , Fleur C. VAN DUYL 1 1 Department of Biological Oceanography, Royal Netherlands Institute for Sea Research, Den Burg, Netherlands, 2 Caribbean Research & Management of Biodiversity, The CARMABI Foundation, Willemstad, Netherlands Antilles, 3 Department of Marine Chemistry & Geology, Royal Netherlands Institute for Sea Research, Den Burg, Netherlands The coral reef framework is a major sink of organic matter. The removal of organic carbon by framework cavities, with volumes ranging from 50-250 dm 3 , in reefs of the Berau area, East-Kalimantan, Indonesia and in the reefs of Curaçao, Netherlands Antilles were in the range, or even exceeded the estimated average gross primary production of a coral reef ecosystem. Dissolved organic carbon removal rates by coral cavities were on average 1 to 2 orders of magnitude higher than particulate organic carbon removal rates. A mass balance for carbon (C), nitrogen (N) and phosphorus (P) was constructed for Curaçaoan coral reef framework cavities. The major fate of C was assimilation, suggesting a rapid turnover of matter for a net increase in biomass close to zero. Relative to C and N, P was selectively retained from the reef water flushing the coral cavities. To directly link the nutrient cycling within the reef framework with the cryptic biota, the organic carbon fluxes were determined for the four dominant communities: (1) Sponge, (2) calcareous algae, (3) sediment, and (4) bare substrate – together accounting for, on average, 88% of the surface of the cavities. Evidently, sponges play a key role in the carbon cycling within the reef framework. Sponges, with an average cavity surface cover of approximately 25%, represented approximately 75% of the total organic carbon flux by coral cavities. Dissolved organic carbon accounted for more than 90% of the total organic carbon removal rate by encrusting sponges. We conclude that the coral reef framework is an important habitat for decomposition and (re)cycling of - to large extent dissolved - organic matter within the coral reef ecosystem. The nutrient cycling is mainly accounted for by a thin veneer of, mostly encrusting, sponges. 19-15 Seasonal Carbon Production And Topographic Features in Sesoko Beach Reef, Okinawa, Japan Hiroyuki FUJIMURA* 1 , Takashi FUKUNAGA 1 , Kyouhei ISHIKAWA 1 , Koujiro SHIMADA 1 , Tomihiko HIGUCHI 1 , Tamotsu OOMORI 1 , Yoshikatsu NAKANO 2 , Tatsuo NAKAI 3 , Beatoriz CASARETO 4 , Yoshimi SUZUKI 5 , Takuji ITO 6 1 Department of Chemistry, Biology and Marine Science, University of the Ryukyus, Okinawa, Japan, 2 Sesoko Station Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan, 3 Kokushikan University, Tokyo, Japan, 4 Laboratory of aquatic science consultant (LASC), Tokyo, Japan, 5 Shizuoka University, Shizuoka, Japan, 6 Mitsubishi corporation, Tokyo, Japan Owing to the global warming and environmental change, coral reefs have been under a serious threat of degradation in the world. In order to understand the present state of coral reefs and predict the future changes, it is important to study a seasonal variation of community carbon metabolism and topographic features in coral reefs. We observed the community carbon metabolism of photosynthesis and calcification every month in Sesoko Beech reef in northwestern part of Sesoko Island, Okinawa, Japan. Most of the corals damaged by mass coral bleaching in 1998 and has not recovered yet. Topographically and biologically different sites were selected as representatives of the reef community in Sesoko. We took water samples every 30min for pH, dissolved oxygen and total alkalinity during slack water periods when the shallow lagoon water (< 80cm) was isolated from offshore. Only two narrow channels is existed and small portion of inside water is flowing out to offshore during low tide. Organic and inorganic carbon productions were estimated from the change in total alkalinity (AT) and total dissolved inorganic carbon (CT) with time. CT was calculated from pH and total alkalinity using a carbonate equilibrium in seawater. Gross primary production was 300-400 mmol/m 2 /d and respiration was 150-300 mmol/m 2 /d. P/R ratio varied 1.3-1.9, indicating the high photosynthesis rate of fringing reef in Ryukyu Islands. While the high organic carbon production, inorganic carbon production of calcification was 45-55 mmol/m 2 /d which is lower value than the other reefs of Okinawa reported before the bleaching. This suggests that the Sesoko coral reef has significantly degraded since coral bleaching in 1998. Further observations are needed to detect the early change in recovery or more additional degradation in the future. 19-16 Temporal Variations in Dissolved Inorganic Nitrogen, Dissolved Gas And Volatile Organic Matter Fluxes Resulting From Sponge Respiration And Microbial Transformations On Conch Reef, Florida Keys (Usa) Christopher MARTENS* 1 , Niels LINDQUIST 2 , Howard MENDLOVITZ 3 , James HENCH 4 , Richard CAMILLI 5 , Anthony DURYEA 6 , Brian POPP 7 , Patrick GIBSON 3 , Melissa SOUTHWELL 3,8 , Jeremy WEISZ 9 , Nyssa SILBIGER 3 1 Marine Sciences, UNC-Chapel Hill, Chapel Hill, NC, 2 Institute of Marine Sciences, UNC- Chapel Hill, Morehead City, NC, 3 UNC-Chapel Hill, Chapel Hill, NC, 4 Stanford University, Stanford, CA, 5 Woods Hole Oceanographic Institution, Woods Hole, MA, 6 Monitor Instruments Company, Cheswick, PA, 7 University of Hawaii at Manoa, Honolulu, HI, 8 UNC-Wilmington, Wilmington, 9 Old Dominion University, Norfolk, VA High nutrient element fluxes from sponges resulting from rapid respiration rates of dissolved and particulate organic matter likely dominate dissolved inorganic nitrogen (DIN) cycling on the Florida Keys reefs and should be dominant in coral reef ecosystems around the world featuring significant sponge biomass. The barrel sponge Xestospongia muta accounts for approximately 60% of sponge biomass in a 600m2 area on Conch Reef off Key Largo, and generates net DIN fluxes exceeding 10 mmol/m2/day, far greater than fluxes from coral substrate and sediments. Respiration by X. muta generally results in a 5-15% oxygen drawdown in the huge volumes of ambient water pumped through its tissues. This sponge and many other plentiful species have a single exit point for all exhaled water, allowing for rigorous in situ quantification of filtration rates and net chemical fluxes utilizing a variety of underwater instrumentation. During two 2007 missions utilizing the NURC/UNCW Aquarius Reef Base undersea observatory, chemical transformations and fluxes resulting from X. muta respiration were quantified continuously for periods of hours to weeks by coupling chemical sensor measurements with acoustic Doppler velocimetry (ADV) pumping rate measurements. Three different instrument arrays, including a newly designed, in situ membrane inlet mass spectrometer (MIMS), were utilized to continuously measure dissolved gases including O2 (mass 32), N2 (28), Ar (40) and CO2 (44,45) plus a variety of volatile dissolved organic molecules. The stoichiometries of O2 consumption, CO2 production and DIN release were utilized to quantify the role of barrel sponges in reef respiration and C and N cycling and to identify potential biogeochemical transformations such as the uptake of dissolved organic matter, N2 fixation and denitrification. The new capability to measure fluxes of volatile organic molecules from sponges using MIMS should provide novel insights into the chemical interactions of sponges with other reef ecosystem inhabitants. 166

Oral Mini-Symposium 19: Biogeochemical Cycles in Coral Reef Environments<br />

19-9<br />

A Role Of Organic Matter In Chemical Symbiosis At Coral Reef<br />

Yoshimi SUZUKI* 1 , Beatriz CASARETO 1 , Sylvain AGOSTINI 1 , M.F.M FARIOZ 1 ,<br />

Kazuyo SHIROMA 1 , Loic CHARPY 2<br />

1 Graduate School of Science and Tecnology, Shizuoka <strong>University</strong>, Shizuoka, Japan,<br />

2 Cyanobacteria Lab., IRD, Marseille, France<br />

Bleaching of corals and damages of the symbiotic zooxanthellae are presently believed to<br />

result largely from elevated temperature of the seawater and the increase of UV radiation.<br />

Mild or moderate bleaching is commonly followed by recovery, but the long-term effects<br />

of high temperature of seawater will end in an irreversible bleaching and massive death<br />

of corals. Due to the impact of rising up seawater temperature, corals receive a strong<br />

stress, and as a result, corals release high amounts of organic matters (mucus) and<br />

ammonia. This means that organic matters in dissolved (DOM) and particulate (POM)<br />

forms might play an important role for the fate of corals and coral ecosystem, especially<br />

in the food web. The production of organic matters by corals can act as a mechanism for<br />

defence but also it is used in feeding for particles capture strategy. High amount of<br />

ammonia in the reefs surrounding waters can enhance the growth of pico-phytoplankton,<br />

which acts as main food source for benthic community. However organic matters may<br />

enhance the growth of certain bacteria, which are known to infect corals and induce<br />

bleaching and diseases. Therefore the understanding of organic matters dynamics is of<br />

extremely importance for the evaluation of coral health. In this paper, the behaviour of<br />

dissolved and particulate organic matters such as concentration, distribution and changes<br />

in its characteristics (composition such as amino acids, carbohydrate and molecular<br />

weight) at the field and during incubation experiments are reported.<br />

We discuss also the significance of chemical symbiosis in coral reef communities.<br />

19-10<br />

Stimulation Of Coral-Derived Organic Matter Release During Bleaching<br />

Wolfgang NIGGL* 1 , Martin GLAS 1 , Christoph MAYR 2 , Christian LAFORSCH 3 ,<br />

Christian WILD 1<br />

1 Coral Reef Ecology Work Group (CORE), GeoBio-Center, Ludwig-Maximilians-<br />

Universität München, Munich, Germany, 2 GeoBio-Center & Department of Earth and<br />

Environmental Science, Ludwig-Maximilians-Universität München, Munich, Germany,<br />

3 Department Biology II, Ludwig-Maximilians-Universität München, Munich, Germany<br />

Corals continuously release mucoid exudates in order to clean their surfaces. But recent<br />

research also showed that this coral-derived organic matter acts as an energy carrier and<br />

particle trap, thus plays an important ecological role for recycling of matter and<br />

conservation of nutrients for the oligotrophic reef ecosystem. Some environmental<br />

stressors such as air exposure, high sediment loads and turbidity are known to increase<br />

mucus production. But although it is a common statement in the literature, scientific data<br />

verifying increased mucus release rates during temperature-induced bleaching events<br />

(loss of symbiotic zooxanthellae from the coral host) are lacking. This is critical as coral<br />

bleaching is the most extensive coral disease world-wide, and bleaching-induced changes<br />

in organic matter release potentially have far reaching consequences for reef functioning.<br />

In this study, we induced a bleaching event and determined release of particulate organic<br />

carbon (POC) and particulate nitrogen (PN) by corals. A new methodology involving<br />

several centrifugation steps was introduced in order to separate released zooxanthellae<br />

from the coral-derived organic matter. Microscopical counting revealed that at least 99 %<br />

of released zooxanthellae could be removed. Our results show that during bleaching on<br />

average 50 % more POC is released whereas PN release rates almost doubled compared<br />

to the unstressed controls. This is the first experimental evidence that coral bleaching has<br />

consequences for organic matter release and ensuing element cycles in tropical reef<br />

ecosystems.<br />

19-11<br />

Bacterial Degradability Of The Organic Matter Released From Symbiotic Coral Colonies<br />

Yasuaki TANAKA* 1 , Toshihiro MIYAJIMA 1 , Yu UMEZAWA 2 , Isao KOIKE 3 , Takeshi<br />

HAYASHIBARA 4 , Hiroshi OGAWA 1<br />

1 The <strong>University</strong> of Tokyo, Tokyo, Japan, 2 Research Institute for Humanity and Nature, Kyoto,<br />

Japan, 3 <strong>University</strong> of the Ryukyus, Naha, Japan, 4 Seikai National Fisheries Research Institute,<br />

Ishigaki, Japan<br />

The organic matter released from corals is well known to be utilized by bacteria and stimulate<br />

the bacterial growth. However, degradability of the organic matter has not been investigated in<br />

a long-term perspective and therefore it is still not understood what % of the released organic<br />

matter can actually be mineralized by bacteria. To investigate the long-term degradability, the<br />

reef-building corals Acropora pulchra and Porites cylindrica were first incubated in a normal<br />

submerged condition or a stressful condition (air exposure), and released organic matter to the<br />

ambient seawater. After taking out of the corals, the incubation seawater containing organic<br />

matter was put under dark over 1 year to follow bacterial decomposition of dissolved and<br />

particulate organic matter (DOM and POM). The results showed that the concentrations of<br />

DOM and POM rapidly decreased within the first 1 week and the remaining organic matter was<br />

gradually decomposed much more slowly, suggesting that the coral-derived organic matter had<br />

two different fractions in bacterial degradability. The labile organic matter (L-OM) had turnover<br />

time of 3.2-9.1 d (average 6.2 d) for DOM and 5.6-9.1 d (average 7.4 d) for POM. The L-OM<br />

could be easily mineralized within or around the reef ecosystem. The stressful condition<br />

increased the ratio of degradable to bulk organic matter. On the other hand, a part of the coralderived<br />

organic matter was not mineralized even after 1 year, suggesting that it was very<br />

recalcitrant to bacterial decomposition. The corals might routinely release such refractory<br />

organic matter to the ambient seawater for defense against pathogens.<br />

19-12<br />

Uptake Of Dissolved Organic Matter By The Scleractinian Coral Stylophora Pistillata<br />

Renaud GROVER* 1 , Jean-François MAGUER 2 , Denis ALLEMAND 1 , Christine FERRIER-<br />

PAGÈS 1<br />

1 Centre Scientifique de Monaco, Monaco, Monaco, 2 Laboratoire de Chimie Marine, Institut<br />

Universitaire Européen de la Mer, PLOUZANE, France<br />

In this work, we investigated the importance of dissolved free amino acids (DFAA) as an<br />

organic nitrogen source for the scleractinian coral Stylophora pistillata. For this purpose, 15Nenriched<br />

DFAAs were used and %15N enrichments were measured separately in both symbiotic<br />

zooxanthellae and animal tissue after incubation of the entire coral colonies at different DFAA<br />

concentrations and light levels. As previously observed for urea, which is another organic<br />

nitrogen source for corals, DFAA uptake is carrier mediated for concentrations below 3 µM and<br />

diffusive for higher concentrations. Our results showed that corals are well adapted to in situ<br />

DFAA concentrations, since they are able to take up DFAAs at very low concentrations (ca. 0.5<br />

µM) and their Km, that represents the carrier affinity for the substrate was also very low. When<br />

normalized to skeletal surface area, uptake rates were ca. twice higher in the animal tissue than<br />

in the zooxanthellae and were enhanced by light exposure. The contribution of DFAA as a<br />

nitrogen source for tissue growth in the coral Stylophora Pistillata was compared to other<br />

nitrogen sources such as ammonia and nitrate for the inorganic part, as well as urea for the<br />

organic part. It ensues that inorganic sources constitute 75% of the daily nitrogen needs against<br />

24% for the organic sources, and that all dissolved nitrogen sources can supply almost 100% of<br />

the nitrogen needed for tissue growth.<br />

165

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