New Research Opportunities in the Earth Sciences - New Research Opportunities in the Earth Sciences - page 57

perturbations that have led to transient states in ocean chemistry and circulation.
These in turn have contributed to major climate change, ocean acidification and
hypoxia, and consequent large-scale biotic impact.
In the tropics, integrated paleoclimate and paleoecology studies can address
the fundamental question of how hot the tropics will become, and to what extent
ocean chemistry will be perturbed, as atmospheric CO 2 continues to rise (NRC,
2011a). Such changes may have dire effects on tropical ecosystems, with the potential
for severe declines in diversity over large areas. The penultimate deglaciation of the
Late Paleozoic Ice Age is the only archival record of the tropical floral response to
climate change associated with the end of a glacial epoch. How Arctic ecosystems
will respond if sea ice disappears permanently—or if the Greenland ice sheet retreats
significantly—can be examined though the lens of past warm periods, such as the
mid-to-late Cretaceous and the early Cenozoic, when the Arctic was ice-free and
supported lush rainforests, warm swamps with aquatic floating plants, and warm-
water fauna.
The forcings that led to past oceanic perturbation, the rates of change and
recovery, the importance of thresholds, and the connections between oceanic change
and biological crises all require further investigation to be properly understood.
Greatly improved dating, refinement and further development and calibration of
proxy records of regional and global climate, and appropriately resolved databases
will permit researchers to reconstruct past changes in Earth's surface environments,
including the atmosphere, oceans, and soil systems, as well as greenhouse gas
burdens (see Box 2.8). These reconstructions will permit characterization of past
climates and will give insights into anthropogenic impacts. Furthermore,
opportunities for new research arise from new techniques, allowing the interaction
between organisms and the environment to be examined directly in living forms
through molecular means and in deep time by integration of phylogenies with proxy
records of environmental and climate change. This involves assessment of the origin
of clades of organisms (both by phylogenetic and phylogenomic methods) and
delineation of the nature of environmental feedbacks that may allow elucidation of
the cause-and-effect conundrum of biotic evolution and major climate change. These
connections resonate with anthropogenic effects in which the biological innovations
that make humans what they are have clearly resulted in changes in carbon dioxide
and other greenhouse gas concentrations, climate, and ecosystem function.
What are the Trends and Milestones in the Interaction and Co-evolution of Life
and the Environment?
The deep time record has revealed events and trends of enormous magnitude
and import well outside the scale of human experience. Some of these events have
been the subject of long-standing inquiry, such as the origin of life, and others are
relatively newly discovered, such as the bolide impact at the Cretaceous-Paleogene
boundary. Opportunities exist for new research at the interface between mechanistic
studies of biological processes such as proteomics, the discovery of new types of and