11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 19: Biogeochemical Cycles in Coral Reef Environments
19.798
Planktonic Carbon Balance Over A Coral Reef System
Paula SPINIELLO* 1
1 Instituto de Zoologia Tropical, Universidad Central de Venezuela, Caracas, Venezuela
The following investigation was conducted to evaluate the temporal dynamic of carbon
supply and demand in the planktonic compartment on a coral reef based system.
Phytoplankton carbon supply was estimated through measurements of primary
productivity and express as mg C/m/day. Zooplankton secondary production, and
ingestion and assimilation efficiencies were used to estimate the carbon demand. Primary
net productivity didn’t show significant variations throughout the study, with values
ranging from 205,02 to 265,22 mgC/m3/day. These values are high compared to other
reefs systems in the Caribbean, which is mainly a consequence of the nutrients input from
the adjacent mangrove system as well as the urban development. Carbon demand by the
zooplankton showed a significant seasonal variation with values ranging from 26
mgC/m3/day at the beginning of the dry season to 209 mgC/m3/day at the end of the
rainy season. The carbon supply throughout the study was higher than the demand,
indicating that the production of autotrophic carbon in the pelagic zone is sufficient to
cover the requirements of the zooplankton community.
19.799
Temporal And Spatial Variability Of Sediment Productivity On A Fringing Reef
(Reunion Island, Western Indian Ocean)
Dorothée TADDEI* 1 , Pascale CUET 1 , Jacques CLAVIER 2 , Patrick FROUIN 1
1 Biology, ECOMAR Lab, University of Reunion Island, Saint Denis cedex 9, Reunion,
2 University of Bretagne, UMR CNRS IUEM, Plouzané, France, Metropolitan
The aim of this study was to assess the contribution of sediments to the carbon cycle in
coral reefs. Productivity was measured at 8 stations (200 m apart) of La Saline fringing
reef (Reunion Island), in winter and summer. Changes in pH, total alkalinity,
temperature, salinity and light intensity (photosynthetically active radiation) at the watersediment
interface were measured in benthic chambers. Community net (CPnet) and gross
(CPgross) productions, and community respiration (CR) were estimated at different times
of the day (and, hence different light intensities). Light response curves were plotted for
productivity using the exponential model. At the whole reef scale, sediments were
heterotrophic with a CPgross/CR being 0.8 ± 0.1. Carbon consumption exceeded
production; sediments were therefore a sink for POC. The reef flat productivity was
steady for the different sites without any seasonal trend (CPnet = 14 ± 12, CPgross = -87 ±
17, CR = 101 ± 11 mmolC m -2 d -1 ). Conversely, back reefs showed a specific pattern of
spatial variations with the highest values recorded in summer. In summer, CR varied
from 88 to 264 mmolC m -2 d -1 and CPgross from -86 to -212 mmolC m -2 d -1 . This pattern
reflected the combined effects of reef currents and groundwater discharge that brings
DIN from land-based human activities. This study 1) confirms the heterotrophic status of
sediments whose communities depend on exogenous organic matter probably originated
from coral/macroalgae communities and 2) highlights a seasonal trend for production in
back reef and as well as a small scale spatial variability which is rarely taken into account
in such reef studies. Finally this work highlights the importance to sample at small spatial
scale in fringing reef to avoid errors in budget calculation.
19.800
Recycling-Oriented Aquaculture System Utilizing Natural Ecological Functions Of
Mangrove Organisms
Yoshimi FUJIOKA* 1 , Chumpol SRITHONG 2 , Ryuichi TABUCHI 3 , Toru SHIMODA 4 ,
Takuro SHIBUNO 4 , Hideo OHBA* 5
1 National Research Institute of Aquaculture, Minami-ise, Japan, 2 Kasetsart University,
Bangkok, Thailand, 3 Forestry and Forest Products Research Institute, Tsukuba, Japan, 4 Seikai
National Fisheries Research Institute, Okinawa, Japan, 5 Tokyo University of Marine Science
and Technology, Tokyo, Japan
Model experiments of a recycling-oriented prawn aquaculture using natural ecological function
of mangrove ecosystem to protect coastal environments including coral reefs were carried out in
Samut Songkhram, the Gulf of Thailand. The survival rate and average weight of prawns,
Penaeus monodon, in the water-circulated culture systems were higher than those in the closed
culture system. When prawns were cultured under semi-intensive conditions in mangrove
planted ponds, their average size increased about by 25%, and artificial feed could be reduced
about by 19% compared to the intensive culture system. Diversity and biomass of the
macrobenthos decreased during the culture experiments in the prawn culture ponds, while they
increased in the mangrove ponds, indicating the possibility that the prawns fed on the small
macrobenthos such as polychaetes and juvenile gastropods as a natural food source. Benthic
and planktonic organisms found in the system were investigated quantitatively and 29
macrobenthos, 22 phytoplankton, 19 zooplankton, 17 algae/seagrass and 2 mangroves were
identified. The results of feed preference experiments and analysis of digested materials
demonstrated that prawns significantly selected polychaetes and crustaceans over commercially
sold pellet feed. On the basis of a serious of study, we constructed a model of a recyclingoriented
aquaculture system by utilizing the natural ecological functions of benthic and
planktonic organisms, mangrove stands and seaweeds.
19.801
Natural Feeding Of Coral Reef Holothurian, Holothuria Atra On Microalgae And
Meiofauna From Seagrass Beds in Chuuk, Fsm
Do-Hyung KANG* 1 , MD Abu AFFAN 1 , Hyun Soo RHO 1 , Sang-Gyu PAIK 1 , Heung-Sik
PARK 1
1 Korea Ocean Research and Development Institute, Seoul, Korea, Republic of
Ansan P.O. Box 29, Seoul 426–744, Republic of Korea
The coral reef holothurian, Holothuria atra (Jäger, 1833) has an important role in nutrient
recycling as a sediment-feeder in coral reef ecosystems. This recycling of nutrients contributes
to the high productivity in coral reefs. Limited information is available on the main food
sources of H. atra, despite their importance on the reefs. This study investigates the food items
(i.e. microalgae and meiofauna) consumed by the sediment feeding holothurian, H. atra.
Sediment samples in front of the mouth, faeces at the posterior and the intestines of the sea
cucumbers were taken from each individual. The different sediment samples were fixed in 10%
formalin for later qualitative and quantitative analysis of microalgae and meiofauna.
Taxonomical determination of microalgae was performed with an inverted microscope.
Extraction of the meiofauna was performed using Ludox HS 40 and the species were identified
to the class level. Total number of microalgae and meiofauna was identified to 25 species and
10 classes in three different samples, respectively. Microalgae and meiofauna in before feeding
sediment were recorded 349 ind. ml–1 and 12.2 ind. ml–1 with the major groups of
Bacillariophyceae and Polychaeta, respectively. After feeding, the microalgae and meiofauna
were ingested up to 85.6% and 79.1% by the holothurians. In the intestine contents, the
abundance of Bacillariophyceae without chlorophyll was higher than other groups while the
abundance of Polychaeta was lower than other groups. This data demonstrated that
Bacillariophyceae and Polychaeta were main ingested food items of H. atra.
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