11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 19: Biogeochemical Cycles in Coral Reef Environments
19.786
Using Fatty Acid Biomarkers And Nutrients in Sediments To Detect Seasonal
Changes in Organic Matter And Nutrient Sources Within A Mixed Coral And
Seagrass Community, Bise, Okinawa, Japan
Preetika SINGH* 1 , Makoto TSUCHIYA 1 , Nakano YOSHIKATSU 1 , Ninomiya
SAYUKO 2
1 University of the Ryukyus, Okinawa, Japan, 2 Tokyo Kyuei Co., Ltd, Kawaguchi, Japan
Changes in fatty acid biomarkers and nutrients in sediments from various areas of a coral
and seagrass moat were analyzed. Sediments near the wastewater pipes leading into the
moat were compared with sediments from the subtidal region, which comprised of a
seagrass bed, and a mixed coral and seagrass community.
The high amount of nitrites (0.7 µMol/g ) from autumn 2006 until spring 2007, and
ammonium (21.6 µMol/g) during the spring season in 2007 observed in sediments near
the wastewater pipes indicates that there is a significant input of nutrients from the
terrestrial sources. The fatty acid results show that the sediments near the wastewater
pipes had a significantly high amount of essential fatty acids (ω3 and ω6 polyunsaturated
fatty acids) in autumn of 2006 and macroalgal fatty acids in winter.
In the subtidal regions, the seagrass bed sediments had the highest amounts of ammonium
(24.4 µMol/g) during the summer season and this was followed by ammonium levels in
the sediments from the mixed coral and seagrass community (17.7 µMol/g). The
sediments also had the highest essential fatty acids and microalgal biomarkers
concentrations during the summer season.
The fatty acids results thus indicate that while the sediments near the wastewater pipe are
contributing a significant amount of organic matter during autumn and winter, the
diatoms and dinoflagellates may be contributing to organic matter within the subtidal
sediments during the summer season.
19.787
Nutrient Enrichment Of A Marine Cage Culture And Its Impact On The
Composition Of Coral Species in The Subtropical Coral Community
Yuan Chao Angelo HUANG* 1 , Pei-Jie MENG 2 , Yung- Song CHEN 3 , Shou Chong
HUANG 4 , Chaolun Allen CHEN 5
1 Institute of Oceanography, National Taiwan university, Taipei, Taiwan, 2 National
Museum of Marine Biology and Aquarium, Pintung, Taiwan, 3 Department of Animal
Science, National IlanUniversity, Ilan, Taiwan, 4 Researcg Center for Biodiversity,
Academia Sinica, Taipei, Taiwan, 5 Research Centre for Biodiversity, Academia Sinica,
Taipei, Taiwan
Offshore cage culture has been demanded increasingly in the oligotrophic water around
coral reefs, particularly in those reefs of developing countries. However, the nutrient
enrichment and its impact on the adjacent coral community remain unexplored. In this
study, the nutrient gradient and the coral species composition in a subtropical coral
community were investigated from 2006 to 2007 in the Makong inner Bay
(23¢X32.471'N; 119¢X35.320'E), Penghu Islands, Taiwan. Three zones, cage, middle,
and none-cage, were divided according to the GPS of cages and coral community. The
results indicated that nutrient enrichment in cage zone was significantly higher, especially
the nitrogenous components (Ammonia) from the metabolized waste of the cultivated
fishes. The other environmental factors presumably affected by cage cultures, including
sedimentation rate, organic matter content, and total suspend solids, were not
significantly different between cage zone and these other two zones. The highest coral
species richness was observed in the middle zone (29 species). In the cage zone coral
species richness was slightly decreased to 20 species, and in the non-cage zone it sharply
decreased to between 4 and14 species. This tendency is also reflected by the variability of
Shannon-Weaver species diversity index. In conclusion, there was a distinct within-reef
zonation in coral distribution. Furthermore, nutrient enrichment caused by effluent from
the cage did not reduce the coral diversity, but changed the species composition of reefbuilding
corals.
19.788
Submarine Groundwater Discharge And Its Role in Structuring Coral Reef Communities
Along The Arid Kona Coast Of Hawaii, Usa
Eric GROSSMAN* 1 , Karen LISA-KNEE 2 , Adina PAYTAN 3 , Ann GIBBS 1 , Josh LOGAN 1 ,
Kathy PRESTO 1 , Curt STORLAZZI 1 , Sallie BEAVERS 4 , Lisa MARRACK 4 , Rebecca MOST 4
1 Coastal and Marine Geology Program, US Geological Survey, Santa Cruz, CA, 2 Stanford
University, Palo Alto, CA, 3 Institute of Marine Sciences, University of California Santa Cruz,
Santa Cruz, CA, 4 National Park Service, Kailua-Kona, HI
Coral reef mapping and measurements of nearshore water temperature (T), salinity (S), Radium
(Ra) isotope quartets, nutrients, waves, and tidal currents suggest that submarine groundwater
discharge (SGD) may play an important role in shaping coral reef communities along the arid
Kona coast of the island of Hawaii. Seasonal and tidal surveys across the reef complex of
Kaloko-Honokohau National Historical Park (KAHO) between Dec 2003 and April 2006 show
persistent discharge of cool, fresh surface water into the nearshore and patterns of transport and
mixing with marine waters. In the absence of stream flow, these data reveal that the source of
this fresh to brackish water is SGD. Fluxes to the park’s coastal waters ranged between 9.4 and
47.0 m3/d/m of coast and are adequate to maintain a buoyant fresh to brackish surface lens
across extensive areas of the reef complex. Nutrient concentrations in groundwater were an
order of magnitude higher than surrounding coastal waters of the park. Northerly, alongshore
currents generally transported this nutrient-rich water through the park from a dominant source
(Honokohau Small Boat Harbor), while large waves mixed the water column to ~10-15 m
depths. Coral zonation largely reflects wave exposure along KAHO, however, the octocoral
Sarcothelia edmonsoni and various green and brown algae were most dense in areas of high
SGD. It is likely that recent increases in municipal groundwater withdrawals and nutrient (urban
chemical) loadings translate to elevated SGD-derived nutrient and contaminant discharges.
Such data provide important near-baseline information for assessing and predicting climate,
land use, and SGD impacts to the area’s fragile ecosystems.
19.789
Detrital Resources in An Undisturbed Coral Reef Food Web: Preliminary Findings From
Palmyra Atoll's Coral Reefs
Lisa MAX* 1
1 Ecology Evolution and Marine Biology, University of California, Santa Barbara, Santa
Barbara, CA
Coral reef food web studies have traditionally focused on the competitive and predator-prey
relationships between reef organisms. These studies often discount the driving roles that
ecosystem processes, such as detritus-cycling, play in maintaining energetic and nutritional
pathways on coral reefs. Detritus, the pool of non-living organic material that organisms
contribute to via metabolic by-products and eventual death, is an important conduit of energy
and nutrients to all trophic levels within ecological communities, yet it receives scant attention
in coral reef food web literature. My preliminary studies on the role of detritus at Palmyra Atoll
National Wildlife Refuge, demonstrate that detrital material is of high nutritional quality, and is
a likely food source for a wide variety of reef organisms in this undisturbed coral reef system.
Stable isotope analyses performed on detrital samples demonstrate that its isotopic signature
varies among Palmyra’s backreef and forereef habitats. Detrital material used in this study was
collected via suction sampling from reef substrates and via sediment traps fixed to the benthos.
In order to characterize the biological community in each sampling area, still photo-quadrats
and fish and invertebrate surveys were carried out. Overall, this study’s findings suggest that
detritus may be an important link in Palmyra Atoll’s coral reef food webs, opening avenues for
further research on Palmyra and other coral reefs systems.
460