Climate change, palaeoceanography and paleo-environment

Climate change, palaeoceanography and paleo-environment - more information is needed on water column processes that impact the deep-sea, and also on paleoceanographic and paleo-environmental processes from subseafloor geological samples that help us understand ecosystem robustness over longer timescales. Oceanic water masses have a controlling effect on today’s seabed ecosystems whilst deep-sea currents, internal waves, the benthic boundary and other hydrological factors strongly influence the substrate type, particle sedimentation or remobilisation, oxygen availability and larvae dispersal, exerting a major control on ecosystem composition. Climate change may bring about changes in water mass properties and strength of currents, which in turn will affect the deep-sea ecosystems, so that extended knowledge about the current seafloor and how it is changing as well as how it has changed in the past. Key issues in this research area will focus on i) obtaining the highest resolution records possible over the last millennia, ii) examining change in a number of environments over the last glacial-interglacial cycle and other large-amplitude climatic events during the past 65 million years, and iii) study biomarkers and DNA of micro-, macro-organisms and viruses which got buried in anoxic environments and where preservation allows us to reconstruct former environments. Very few species are preserved as a whole in deep-sea environments with the exception of calcareous and siliceous microfossils; hence other methods like the use of biomarkers, but also new subseafloor sampling techniques are essential. Sediment composition and structures can reveal many characteristics of paleo-seabed and geochemical and biological analysis of planktonic and benthic microfossils and organisms can reveal much about paleo-seawater chemistry at former times.

Related to subseafloor sampling, the ESF EuroMARC program currently supports projects such as CHECREEF (related to the upcoming IODP expedition drilling the Australian Great Barrier Reef), GLOW (reconstruction of temperature history during Paleogene global warming events), or MOCCHA (using high-resolution sediment records in the Mediterranean Sea). Other important examples include the IPCC effort (which partly relies on drill core information) or the PAGES and IMAGES programs. Only detailed knowledge of high-resolution variations in Earth climate and environment in the past will enable mankind to reach predictive capabilities for climate change, ocean acidification, and sustainable use of the ocean and deep-sea in the future.