Marine Ecosystems Research Department - jamstec japan agency ...

Japan Marine Science and Technology Center
Research Activities
Marine Ecosystems Research Department
Introduction
Recent marine biological research has revealed extensive biological populations of great diversity from midwater
to ocean bottom layers, and also within the earth's crust beneath the seafloor. These discoveries have altered our
whole concept of the global biosphere, and have given rise to the need to tackle the following issues:
Reconstruction of the marine ecosystem model into a dynamic model of material circulation with interaction
between photosynthetic ecosystems in shallow sea areas and chemosynthetic ecosystems primarily on the deep
seafloor.
Elucidation of marine biological evolution and the interaction between the environment and organisms.
The Marine Ecosystems Research Department will therefore finalize research on "clarifying the mechanism of
changes in marine ecosystems" in fiscal , and restructure this to the project of "Study for Understanding of
Function and Structure of the Marine Ecosystems in the Earth System" in fiscal . Viewing the earth as a system
and understanding its dynamic changes within the global ecosystem network is vital to the overall research direction
of JAMSTEC. The following are the key focus points of our research.
Clarifying the mechanism governing diversity through marine organisms (research into diversity).
Clarifying the biological functions relating to biological production and material circulation in marine ecosystems
(research into ecosystems).
We will link these to OD/IODP, which will start in , and establish methodologies and research structures
for analyzing crustal biospheres in plate boundary and hydrothermal vent zones, their biological interaction with
marine ecosystems, and material circulation. Through this, we will determine the structure of ecosystems extending
from the crust to the ocean, and their role in the global system. Regarding biological production and material circulation
in the surface layers, we are looking to undertake cooperative research with institutions whose research focus
is in this area (fishery research laboratories, universities, and the Ocean Observation and Research Department).
Research Project Category 1
Research and Development of Coral Reef Recovery
Techniques
Period: FY-
Coral reefs are rich in their diversity of marine organisms
and are unique in that while they have extremely
high levels of bioproductivity, they are oligotrophic.
What supports this high bioproductivity is the symbiotic
system formed by symbiotic microalgae typified by the
zooxanthella, and the coral and other invertebrates. In
recent years there have been frequent reports of a collapse
in this symbiotic system as seen in widespread
coral bleaching in coral reefs throughout the world, and
one of the causes of this is said to be environmental
change such as global warming and an increase in ultraviolet
radiation. In this sense, coral reefs can be seen as
a barometer of global environmental change.
Extensive field surveys have been carried out on the
connection between the environment and bleaching of
symbiotic systems such as coral and giant clams
(Tridacnidae) that underpin coral reefs, but details
about the mechanisms by which symbiotic systems
collapse, such as bleaching, have thus far remained
elusive. The reason for this is that the interaction
mechanism between the host and the microalgae symbionts
is not fully understood. For example, microalgae
secrete more than % of their photosynthetic
product into the host, but the signal (host factor) of
this is as yet not clear. To understand this collapse in
the symbiotic system, we have to shed light on the
symbiotic mechanism that sustains coral reefs, and
this in turn will help us to understand the mechanism
of chloroplast acquisition in the process of biological
evolution.
49