05/09/2023 | A look back at environmental change throughout geologic history can tell us a lot about the future – especially when it comes to globally and societally important topics such as sea level, climate change and coral reef ecosystem health. An international scientific research expedition, carried out on behalf of the International Ocean Discovery Program (IODP), aims to recover a record of past climate and reef conditions off the coast of Hawai’i (USA). The two-month research expedition will leave the port of Honolulu at the end of August. ZMT geologist Prof. Dr. Hildegard Westphal is also taking part in the expedition.
Coral reefs are very sensitive to sea level and other changes in environmental conditions. As fossils they provide a record of past conditions over many millions of years of Earth’s history. There is, however, a discontinuity in the global record over the past 500,000 years during periods of major and abrupt climate and therefore sea level instability.
The IODP Expedition 389 “Hawai’ian Drowned Reefs” focusses on these periods of pronounced fluctuations in order to investigate the difference between short-term weather shifts and climate changes.
The scientific expedition is led by Co-Chiefs scientists Professor Christina Ravelo (Ocean Sciences Department at the University of California, Santa Cruz, USA) and Professor Jody Webster (School of Geosciences, the University of Sydney, Australia).
Prof Christina Ravelo says that the Hawai‘ian fossil reefs are storytellers of the past climate and ocean changes and of the reef ecosystem responses to those changes. “These stories can be unlocked through careful study of the fossils that we hope to recover,” she explains.
Prof Jody Webster adds: “We hope that information recorded in the fossil reefs will help scientists make improved predictions about the rate and magnitude of sea-level rise, what impact global warming and cooling has on short-term climate phenomena like droughts, floods and marine heat waves, and how coral reef ecosystems respond to these changes.”
Prof. Dr. Hildegard Westphal, head of the research group on Geoecology and Carbonate Sedimentology at the Leibniz Centre for Tropical Marine Research and professor at Bremen University, participates in the onshore phase of the expedition. There, together with the international team, she will study and sample the cores at the core repository at MARUM in Bremen. She emphasizes: „This long-awaited research expedition will allow us to better understand climate dynamics and the reaction of coral reef ecosystems to those disturbances. This includes their resilience towards changing temperature, nutrients, and light conditions. Coral reefs have been confronted with extreme environmental changes in the last 500.000 years. How did they manage to cope?“
Dr. Thomas Felis, head of the Coral Paleoclimatology working group at MARUM - Centre for Marine Environmental Sciences at the University of Bremen, is a member of the expedition team. "After earlier coral reef drilling expeditions to the Great Barrier Reef and Tahiti, in which I was involved, Hawai'i now offers a unique opportunity, to go back much further into the past, hopefully up to half a million years," says Dr. Felis, who also coordinates the DFG Priority Programme "Tropic Climate Change Activity & Coral Conflict" (SPP 2299).
Map of the proposed sites for IODP Expedition 389 | Credit: ECORD
Deep sea coring systems to be used
The expedition aims to recover cores from water depths between 134 and 1,155 meters at a maximum of twenty locations. Even though this will be the first time that a seafloor coring system will be deployed in this area, the anticipated sites are well studied. “We have a very good idea of what the seabed looks like off the coast of Hawai’i based on extensive mapping using underwater sonar, as well as footage and surface samples collected using submersibles and remotely operated diving robots by scientists over the past four decades”, says Jody Webster. “This information has helped us select the best places to carefully collect the cores that will deepen our understanding of the history of the reef system”, adds Christina Ravelo.
The scientific objectives of the expedition aim to address questions on four main topics:
- To measure the amplitude and effects of sea level change over the past half a million years
- To investigate why sea level and climate changes through time
- To investigate how coral reefs respond to abrupt sea level and climate changes, and
- To improve scientific knowledge of the growth and subsidence of Hawai’i over time.
Universität Hawai‘i joins as partner institution
The University of Hawai’i is a partner institution for this expedition and has a strong tradition of science in coral reefs, littoral phenomena, and shoreline geology. Hawai’ian scientists have been studying sea level change and its impacts and have highlighted how this knowledge is important for formulating a mitigation and resilience strategy for the future. Prof Kenna Rubin, Inorganic Geochemist at the University of Hawai'i at Manoa, Department of Earth Sciences, has been involved in planning of the expedition from the beginning and will be a key participant.
Prof Kenna Rubin: “These detailed, high-resolution temporal and compositional records anticipated from this expedition will add greatly to our knowledge of responses to climate change, as well as helping scientists to better understand the volcanic subsidence history of the Big Island. The impacts of this research in Hawai’i will contribute to existing studies of sea level change as recorded here by coral reefs.”
About the research expedition conducted by the European Consortium for Ocean Research Drilling (ECORD)
A team of 29 scientists from Australia, Austria, China, Denmark, France, Germany, India, Japan, the Netherlands, Great Britain and the USA will participate in the expedition. Ten of them will sail onboard the MMA VALOUR, which has left Honolulu port on August 31. The offshore phase of the expedition will end on October 31. All science party members will meet for the onshore phase at the IODP Bremen Core Repository, located at MARUM – Center for Marine Environmental Sciences at the University of Bremen (Germany) to split, analyze and sample the cores and interpret the data collected in February 2024.
After analysis, the cores will be archived long-term and made accessible for further scientific research for the scientific community after a one year-moratorium period following the onshore phase of the expedition. All expedition data will be open access and resulting outcomes published.
The expedition is conducted by the European Consortium for Ocean Research Drilling (ECORD) as part of the International Ocean Discovery Program (IODP). IODP is a publicly-funded international marine research program supported by 21 countries, which explores Earth's history and dynamics recorded in seafloor sediments and rocks, and monitors sub-seafloor environments. Through multiple platforms – a feature unique to IODP – scientists sample the deep biosphere and sub-seafloor ocean, environmental change, processes and effects, and solid Earth cycles and dynamics.
ECORD Science Operator has great experience working in sensitive ecosystems such as coral reefs, following seagoing expeditions to the Great Barrier Reef (Australia, 2010) and Tahiti (2005).
About the multipurpose vessel MMA VALOUR
In order to recover the material that scientists will analyze in the coming years, a seafloor corer will be deployed off the multipurpose vessel MMA VALOUR during the expedition. The seafloor corer will be provided and operated by a renowned geotechnical industry specialist, to be lowered to the ocean floor to recover up to maximum 110-meter-long cores beneath the seabed.
The MMA VALOUR is a versatile multi-purpose platform supply vessel, owned and operated by MMA Offshore, a leading provider of marine and subsea services globally. Headquartered in Perth, Australia, MMA is committed to protecting the world’s marine ecosystems and supporting critical scientific research in this area.