Future Science Opportunities in Antarctica and the Southern Ocean (2011) / Chapter Skim
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3 Fundamental Questions of Scientific Discovery
3 Fundamental Questions of Scientific Discovery
Pages 75-108
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From page 75... ...
New lakes were discovered underneath miles of ice on the Antarctic continent, including Lake Vostok, with as large an area as Lake Ontario. New information about the Antarctic ice sheet and the sea ice surrounding it has been obtained from satellite-based observations.
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From page 76... ...
Physical and chemical analyses of sediments, rocks, and organisms retrieved from ocean drilling cores provide additional important records of past climate conditions including ocean temperatures, salinity, circulation, and biological productivity. These cores have been drilled beneath the West and East Antarctic ice sheets, beneath floating ice shelves, and across the continental shelf beneath the Southern Ocean.
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From page 77... ...
This ice provides a unique high-temporal-resolution archive of past climate conditions locally, as well as regionally and globally. Chemical and physical measurements are made on samples from the ice cores extracted from the ice sheets, as well as from the gas trapped in tiny bubbles within and between the ice crystals (see Figures 3.1 and 3.2)
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From page 78... ...
Deep ice cores (~1-3 km) collected from West Antarctica, where accumulation rates are considerably higher than in East Antarctica, are also important.
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From page 79... ...
Additionally, multiple boreholes surrounding any new deep ice cores provide greater spatial context, without the need for retrieving multiple deep ice cores at any one location. Overall, arrays of ice, rock, and sediment cores are needed to reduce the noise inherent in any single core's record and to investigate the spatial nature of past climate variability.
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From page 80... ...
to a climate in which larger ice sheets grew and then quite rapidly collapsed over intervals of about 100,000 years. From analysis of Antarctic ice cores, atmospheric CO2 levels are known to closely track the global temperature and ice volume during the past 800,000 years; but why did glaciation vary with a different period earlier?
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From page 81... ...
3.2 HOW HAS LIFE ADAPTED TO ANTARCTICA AND THE SOUTHERN OCEAN ENVIRONMENTS? Global Context The Antarctic Ocean and continent pose extreme challenges for organisms to survive there, from bacteria and fungi to plants and vertebrates.
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From page 82... ...
These are examples of the potential knowledge to be gained from the many organisms living in this extreme environment. On the Antarctic continent, there are the many reminders that Antarctica is a polar desert, including the freeze-dried, mummified remains of seals in the Dry Valleys that have been preserved for decades.
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From page 83... ...
Not only can the survival mechanisms of life in Antarctica teach us about the world and provide insights for improving the human condition, but also studies of Antarctic life can provide a window from which to search for life elsewhere in the universe, especially the solar system. The McMurdo Dry Valleys have long been considered the best terrestrial analogue for Mars (Doran et al., 2010)
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From page 84... ...
, including the 14-million-year-old liquid Lake Vostok that lies beneath about 12,300 ft of ice and may soon be accessible to scientists, represent important analogs and testbeds for a future Europa mission. More to the point, however, sampling subglacial lakes will provide access to early life forms frozen in time.
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From page 85... ...
These investigations will be central to understanding the physiology of metabolic pathways of cells under extreme environmental conditions of Antarctica. Genomic, proteomic, and metabolomic studies allow scientists to address how changes in temperature and seawater chemistry, associated with rising atmospheric CO2, affect a host of biological processes in individual organisms and communities of protozoans and metazoans.
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From page 86... ...
Required Tools and Actions To advance understanding of the fundamental biology of organisms from bacteria to mammals, and how they function in the Antarctic ecosystem, new tools and infrastructure for exploration and discovery will be essential to identify the diversity of life and its functioning in the extreme environment of Antarctic glaciers and oceans. Examples include the following: • Ice coring and ultraclean sampling technologies for subglacial lakes and other under-ice environments; • Sensor networks for environmental monitoring and recording animal behavior and migration; • Remote sensing to monitor vegetation and land expansion; • Genome surveys and sequencing technology -- A Census of Antarctic Life that builds on the Census of Antarctic Marine Life to include life in sea ice, glaciers, permafrost, terrestrial, and aquatic ecosystems; an initial focus on metagenom ics would be most fruitful; • Extensive upgrades of lab facilities to accommodate the newest technologies and advanced analytical facilities for genomics, metagenomics, proteomics, and metabolomics; the volume of sample processing and analysis will demand on-site analyses; on-site analysis becomes necessary to avoid the dissipation of metabolic function or other problems that can occur if samples are frozen and then analyzed weeks after collection; • Increased communications capability -- larger bandwidths for data transfer from sensor networks in real time (for example, for sensors placed temporarily on Antarctic vertebrates transmitting to polar orbiting satellites, and for envi ronmental data and genetic information from instruments in the field)
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From page 87... ...
In order to gain mechanistic understanding of how global changes will affect Antarctic ecosystems, infrastructure is needed to carry out hypothesis-driven experiments at the scale of a landscape or ecosystem in strategically selected locations such as the Dry Valleys or penguin rookeries. Scientific rationales and potential impacts will have to be carefully described to gain permission under treaty provisions for such large-scale studies.
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From page 88... ...
. As society becomes more dependent on space-based technologies, we become more vulnerable to severe space weather events, which now have the possibility of disrupting large parts of society's infrastructure.
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From page 89... ...
but also power grids on the surface, possibly leaving many areas of the United States without electric power for months. In order to predict space weather it must first be understood.
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From page 90... ...
Antarctica can play a critical role in realizing that vision, both in scientific research and the application of that research to operational systems for space weather monitoring and prediction. Antarctica provides a unique platform for space weather research and monitoring because, unlike the oceanic Arctic, year-round ground-based observations from areas across the Antarctic continent are possible.
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From page 91... ...
Looking further ahead, understanding the solar cycle and long-term solar variations is a critical question for a space-based civilization. Required Tools and Actions Space weather modeling, following the lead of tropospheric weather prediction, is beginning to incorporate techniques such as ensemble and probabilistic forecasting, and data assimilation.1 The latter requires a high density of observations (such as full coverage of the Antarctic ionosphere from incoherent scatter radars)
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From page 92... ...
The bulk of the 17th century was a period of very suppressed solar magnetic activity that was coincident with a period of cool temperatures in Europe and elevated cosmic rays; this was due to the weak solar magnetic field that shields the heliosphere from the galactic cosmic ray flux. Long-term cosmic ray and atmospheric observations made in Antarctica can provide important data to study whether there is in fact a link between cosmic ray flux and climate.
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From page 93... ...
New instruments have opened up an entirely new window on the universe in the form of neutrino astronomy. Antarctica plays a unique and pivotal role in the pursuit of these questions by providing exceptional atmospheric conditions -- high, cold, dry, and stable -- for viewing the fossil light from the Big Bang and the cosmic microwave background radiation, and by providing the large volumes of exceptionally transparent and stable ice for detecting high-energy neutrinos from space (see Box 3.4)
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From page 94... ...
For example, astronomical objects viewed from the South Pole never rise or set but remain at the same elevation, allowing exceptionally long, deep, and uniform observations. Over the past two decades the push has been to obtain increasingly sensitive measurements of the intensity and polarization of the cosmic microwave background.
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From page 95... ...
This space exponentially expanded faster than the speed of light to produce a universe much larger than can be observed currently. This explanation accounts for the isotropy of the background radiation, that is, the fact that background radiation reaches Earth uniformly from all 95
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From page 96... ...
The horizontal axis represents time and the vertical width represents the change in the rate of the expansion of the universe. After a period of exponential expansion, the epoch of inflation in the first instants of the universe, there is a long period of slowing expansion during which the galaxies and large-scale structures formed through the force of gravity, followed by recent acceleration of the expansion due to dark energy.
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From page 97... ...
Astrophysicists hope to test this theory, known as Inflation, by searching in the polarization of the CMB radiation for the tell-tale signature of gravitational waves generated in the inflationary epoch. The model also includes the makeup of the universe, as determined from analysis of the cosmic microwave background radiation (see Box 3.5)
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From page 98... ...
The map is dominated by features in the cosmic microwave background radiation, the 14 billion-year-old fossil light from the Big Bang. The features are detected at high signal to noise throughout the map (the noise level is ~18 mK)
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From page 99... ...
Fundamental Questions of Scientific Discovery BOX 3.5 CONTINUED FIGURE 2 The angular power spectrum of the structure from maps of the cosmic microwave background radiation. Much like a graphic equalizer display illustrates the makeup of music as a function of wavelength, i.e., with the bass at long wavelengths (low frequencies)
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From page 100... ...
" requires a multipronged approach including cosmic ray observatories, space- and groundbased gamma-ray observatories, and importantly -- but only recently possible -- highenergy neutrino observatories. Neutrinos are nearly massless particles that carry no charge, and because they interact only via the weak interaction, that is, not via electromagnetic interactions, they travel from their source unaffected by magnetic fields or interactions with the cosmic microwave background.
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From page 101... ...
To separate the desired cosmic background signal from the contaminating sources of polarized emission, the sky will need to be mapped in several wavelength bands and at an angular resolution of a few arc minutes or better, so the unique spectral and spatial signatures of the signal can be observed. The astrophysics community has begun planning ahead for possible future developments using long-duration Antarctic balloons and enhancements to the observing program at the South Pole to produce these maps.
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From page 102... ...
. The detector searches for the flash of blue Cherenkov light emitted from the FIGURE 1 Schematic view of the IceCube neutrino observatory at the South Pole.
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From page 103... ...
In this way Earth itself serves as the telescope and the Antarctic ice cap as the detector. FIGURE 2 Display of a typical muon neutrino event in IceCube.
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From page 104... ...
A neutrino observatory large enough to collect hundreds of neutrinos that were created by the interaction of ultra-high-energy cosmic rays with the cosmic microwave background (the GZK effect; Greisen, 1966; Zatsepin and Kuzmin, 1966) would provide two unique discovery opportunities.
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From page 105... ...
What Is the Star Formation History of the Universe? These questions represent only a sample of the astrophysics beyond the study of the cosmic microwave background, for which the unique atmospheric properties and geographical location of Antarctica provide opportunities for dramatic advances.
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From page 106... ...
The scientific community has learned how to carry out challenging astrophysics projects from the successful program at the South Pole. Indeed the South Pole station itself would provide valuable testing and staging opportunities for experiments to be deployed at less developed sites, or for remote robotic astrophysical installations.
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From page 108... ...
The Research Vessel NATHANIEL B PALMER in Barilari Bay, Antarctic Peninsula.
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