Climate Change Research in University of the Ryukyus

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1 IPCC Open Symposium New scientific findings on climate change and the importance of GHG inventory to assess mitigation progress 16 March, 2015 Climate Change Research in University of the Ryukyus Dr. Kazuhiko SAKAI Sesoko Station Tropical Biosphere Research Center University of the Ryukyus 1

2 Menu Global warming and corals in Okinawa Global trend in corals, and field studies in Okinawa Belief introduction of climate change research in University of the Ryukyus Introducing climate change related research activities by faculty members and researchers in University of the Ryukyus

3 Reef corals play central role in coral reef ecosystems Provision of complex habitats Coral zooxanthella holobionts are main primary producers Bacteria in coral cells and skeletons fix nitrogen

4 When corals are disappeared, biodiversity, function, and service of coral reef ecosystems are collapsed 4

5 Zooxanthellate reef corals ( corals ) have been threatened by global and local anthropogenic environmental changes Global (climate change) Global warming Ocean acidification Local Eutrophication of seawater Overfishing Soil runoff Reclamation I will focus on the global issues today

6 Sesoko Station, Tropical Biosphere Research Center University of the Ryukyus

7 Coral communities in 1980

8 The same reef in 2002

9 World wide mass coral bleaching in 1998 Effect of global warming? At least simulation of Healthy Acropora Bleached Acropora Bleaching is response of corals to stresses. Corals are bleached by losing zooxanthellae. In 1998, the stress was high temperature and strong light. 9

10 Changes in coral community by the 1998 mass bleaching on the reef flat of Sesoko I. 1. Percentage cover of coral community was decreased by 85% 2. Number of coral species was decreased by 61% 3. Winners (massive corals) and Losers (branching corals) (Loya et al. 2001) 10

11 Corals had come back to the reef flat by 2011

12 In 2002, no visible branching corals on reefs of Onna V. 12

13 Coral communities have recovered at other localities in Okinawa I. Yamada, Onna V Mannza, Onna V. 2014

14 In summary, coral populations/ communities still have the potential to recover in Okinawa.

15 Menu Global warming and corals in Okinawa Global trend in corals, and field studies in Okinawa Belief introduction of climate change research in University of the Ryukyus Introducing climate change related research activities by faculty members and researchers in University of the Ryukyus

16 Additional research activities on coral reef organisms Dr. Haruko Kurihara, Faculty of Science Experimental evaluation of climate change on corals, sea urchins, mollusks Dr. Saki Harii, TBRC (Tropical Biosphere Research Center) An international research team including Dr. Harii found that, If seawater temperature increases by the global warming, coral larvae will retain natal reefs at a rate several times higher than at the present, using data from aquarium experiment and mathematical model. 16

17 Typhoons Dr. Hiroyuki Yamada and Dr. Kosuke Ito, Faculty of Science 理学部山田 Global warming and typhoons They found that number of typhoons would decrease but each typhoon would be more destructive if the global warming progressed using mathematical simulation. The simulation indicated that the central pressure of a typhoon would decrease by 10hPa if seawater temperature increased by 1.

18 Effect of typhoons on coral reefs 1 Dr. Chuki Hongo, Faculty of Science He found that table corals were damaged more than massive corals by a typhoon in Ishigaki Island. He conducted an analysis by hydrodynamic model, and predicted that, if typhoons would be more destructive by the warming, table corals that contributed much to coral reef ecosystems would be damaged much more.

19 Effect of typhoons on coral reefs 2 Dr. Yoshihisa Fujita, Education Center Dr. Tohru Naruse, TBRC Dr. James Reimer, Faculty of Science Corals on reefs deeper than 25 m were much affected by typhoons in Kume Island and Onna Village of Okinawa Island. A branching corals before (B)and after (D) a typhoon at Nanhanari Reef, Kume Island. The branching corals were broken into fragments after the typhoon.

20 Climate change in the past 1 Dr. Ryuji Asami, Dr. Ryuichi Shijyo, and Dr. Masahide Furukawa, Faculty of Science Seasonally resolved records of carbon and oxygen isotopic composition in fossil shells of giant clams (Tridacnidae) recovered in Okinawa Island. These results demonstrate that annual mean seawater temperature and salinity at the sites where the Tridacnida spp. lived were about 1 3 higher and/or about 1 2 lower than at present. This variation cannot be fully explained by global climate change, sea level change, and topographic growth of coral reef. Therefore, it is likely that the giant clams lived in extremely small and/or closed coral reef lagoons with less water circulation where seawater is highly susceptible to insolation induced temperature increase and input of fresh water.

21 Climate change in the past 2 Dr. Ryu Uemura, Faculty of Science Analyses of the past climate changes using stable isotope ratios Reconstruction of the past climate changes using stable isotopes Reconstruction of the climate change in the past 700 thousand years using stable isotope ration of water of the Antarctic ice sheet

22 Climate change in the past 3 Dr. Kazuhiko Fujita, Faculty of Science Analyses of the effect of ocean acidification and reconstruction of the past climate change using large foraminifera Precise reconstruction of seawater temperature and sea surface level in Okinawa from 3 million years ago to the present using tests of large foraminifera. Reconstruction of the formation process of a sea cave in Ie Island using tests of large foraminifera as a record of light environment.

23 Temperature change in Japanese cities Dr. Junichiro Tsutsumi, Faculty of Engineering By analyzing air temperature at cities in Japan, he found that the mean air temperature had on an average increased by 1 in the past 100 years. Air temperature in large cities had increased more than the average. The increase in annual lowest temperature was great in the large cities, suggesting the occurrence of the heat island phenomenon there.

24 Activities in overseas countries Dr. Takashi Nakamura, Dr. Haruko Kurihara, Dr. James Reimer, Faculty of Science; Dr. Yoko Fujita, Faculty of Law and Letters SATREPS at Palau: Sustainable Management of Coral Reef and Island Ecosystems: Responding to the Threat of Climate Change Palau and other Pacific states have abundant coral ecosystems and some of the world s richest biodiversity. However, they face a changing global environment, including climate change and ocean acidification, as well as the growing impact of regional development issues like coastal development and water pollution. This project takes both global and local perspectives, working through activities such as environmental monitoring, environmental impact assessments for coral island ecosystems, social scientific assessments, and assessments of impact on biodiversity to produce suggestions concerning sustainable approaches for island society.