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International Journal of Marine Science 2013, Vol.3, No.36, 285-294
http://ijms.sophiapublisher.com
285
Research Article Open Access
A Stable Isotope Study of the Relationship between Coral Tissues and
Zooxanthellae in a Seasonal Tropical Environment of East Kalimantan, Indonesia
Handoko Adi Susanto
1
, Makoto Komoda
2
, Masaaki Yoneda
2
, Akihiro Kano
3
, Mutsunori Tokeshi
4
, Hiroko Koike
3
1. Marine Protected Areas Governance, Jl. Wolter Monginsidi No. 63B. Kebayoran Baru, Jakarta Selatan, 12180. Indonesia,
2. Japan Wildlife Research Center, Taitoku, Tokyo, Japan
3. Department of Environmental Changes, SCS, Kyushu University, Motooka, Nishiku, Fukuoka, Japan
4. Amakusa Marine Biology Laboratory, Department of Biology, Faculty of Science, Kyushu University, Japan
Corresponding author email: handoko.susanto@cbn.net.id
International Journal of Marine Science, 2013, Vol.3, No.36 doi: 10.5376/ijms.2013.03.0036
Received: 26 May, 2013
Accepted: 23 Jun., 2013
Published: 02 Jul., 2013
Copyright
©
2013 Susanto et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Susanto et al, 2013, A Stable Isotope Study of the Relationship between Coral Tissues and Zooxanthellae in a Seasonal Tropical Environment of East
Kalimantan, Indonesia, International Journal of Marine Science, Vol.3, No.36 285
-
294 (doi: 10.5376/ijms.2013.03.0036)
Abstract
This study assessed variations in the relationship between zooxanthellae and their coral hosts seasonally and spatially.
Carbon and nitrogen stable isotopes (
δ
13
C and
δ
15
N) were used to analyze the patterns of nutritional transport between coral and
zooxanthellae. Studies of temporal differences were conducted during two dry seasons and one rainy season in the Berau Marine
Conservation Area, East Kalimantan, Indonesia. To assess spatial variations, coral samples from three genera (
Porites
,
Seriatopora
and
Stylophora
) were collected from three localities, designated as nearest, medium, and farthest from the Berau River mouth. The
lower
δ
13
C of
Seriatopora
compared with the other two genera suggested that corals in this genus were more actively utilizing
particulate organic matter and adopting a heterotrophic feeding mode. The
δ
13
C values of coral tissue and zooxanthellae also were
affected by differences in seasons, localities, and depth, whereas the
δ
15
N values varied significantly with seasons alone. Differences
in
δ
15
N values between coral tissue and zooxanthellae were always positive in the first and second dry seasons, but negative in the
rainy season. This finding indicated that zooxanthellae were the main source of coral nutrients during the dry season, while host coral
may support zooxanthellae nutrition during rainy season of low turbidity. Spatially, sedimentation does not show significant impact
to the relationship between coral and zooxanthellae.
Keywords
δ
13
C;
δ
15
N; Coral; Zooxanthellae; East Kalimantan; Indonesia
1 Introduction
Coral reefs are one of the most productive marine
ecosystems (Birkeland, 1997) and they harbor over
4000 different fish species, 700 coral species, and
thousands of other plants and animals (McAllister et
al., 1994; Hinrichsen, 1997). Such systems typically
have high photosynthetic production reaching 5–20 g
m
–2
day
–1
of organic carbon or 50–200 g m
–2
day
–1
of
wet biomass (Sorokin, 1993). However, coral reefs are
declining in many areas of the world as a result of
steadily increasing threats from direct human pressure
(Chansang et al., 1981; Pastorok and Bilyard, 1985;
Fabricius, 2005; Marion
et al., 2005) and the indirect
effects of global climate change (Hoegh-Guldberg,
1999; Hughes et al., 2003; Hoegh-Guldberg et al., 2007).
The role of reef construction is mostly performed by
reef-building (or hermatypic) corals. Many hermatypic
corals have a symbiotic relationship with algae called
zooxanthellae (Sorokin, 1993). These algae live inside
coral polyps and perform photosynthesis, producing
carbon compounds that are shared with the coral. In
turn, the coral provides the algae with protection and
access to light. Zooxanthellae utilize nitrates,
phosphates, and carbon dioxide produced in the polyp
and also lend their color to their coral symbionts.
Coral bleaching occurs when corals lose their
zooxanthellae, thereby exposing the white color of the
calcium carbonate skeleton through the transparent
coral body.
Variations in the relationship between corals and their
zooxanthellae can be assessed by analyzing carbon
and nitrogen isotopes. Pioneering work by Johannes
and Wiebe (1970) on the nutritional relationship
between hermatypic scleractinian corals and zooxanthellae
determined the coral tissue biomass and composition
using a water-pick method to separate zooxanthellae