Future Needs in Deep Submergence Science Occupied and Unoccupied Vehicles in Basic Ocean Research (2004) / Chapter Skim
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2 Understanding Deep Submergence Science
2 Understanding Deep Submergence Science
Pages 23-42
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From page 23... ...
· Presents a coherent and logical definition of deep submergence science (to support calls for consistent, equitable, and transparent mechanisms to provide access to scientific assets) Research carried out at depth in the ocean over the last 40 years has provided dramatic and unique insights into some of the most compelling scientific questions ever posed.
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From page 24... ...
to the ocean floor; from continents to the depths of the ocean basins; from plate boundaries at spreading ridges and ocean trenches to the remains of ancient and recent civilizations. The diverse nature of deep submergence science necessitates the use of a mix of expertise, approaches, platforms, and tools.
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From page 26... ...
Submergence science provides a powerful way for conducting important research in the geosciences and biological sciences. The subsequent sections discuss only a few examples of the most compelling scientific challenges that call for access to the ocean depths.
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From page 28... ...
, and benthic chemosynthetic ecosystems sustained primarily by natural expulsion of nutrient-bearing fluids from overpressured sediments and rocks. Cold seeps, mud, and serpentine dippiest and the associated chemosynthetic ecosystems were discovered with submersibles, and the great majority of what is known about this new frontier of science was obtained from the use of deep submergence vehicles.
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From page 29... ...
. These vents result from seawater convection cells that are activated by magmatic heat, either from magma chambers located beneath the ridge or from cooling magmatic rocks.
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Because of improved research techniques these studies will require repeated cruises and more submersible time to conduct experiments and to deploy and recover instruments on the seafloor. Logistically, some of the selected sites Juan de Fuca Ridge, East Pacific Rise)
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conditions and effectively fluidize sediments and rock, probably manifest in the formation of mud volcanoes. High fluid pressure may also reduce the effective strength of faults and earthquakes that cause fracturing, facilitating focused fluid flow.
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These include determining the mass flux of meteoric water versus seawater recycling in the ocean; the consequences of various flow regimes for ocean chemistry, benthic biology, and slope stability; the sedimentological and tectonic controls on hydrology; the influence of hydrology on accumulation and migration of hydrocarbons and gas hydrates; and the magnitude and spatial distribution of the driving forces on fluid flow. The hydrological regimes of passive rifted margins are
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From page 33... ...
The lateral and depth extent of passive margin fluid flow systems is not well understood. Major advances in understanding these processes, and the environmental consequences will depend on accessibility to existing and new platforms for deep submergence science.
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From page 34... ...
Global fluid fluxes and their impact on ocean geochemical budgets are unknown. Instrumenting and sampling focused fluid flow sites for short- and long-term monitoring of chemistry and fluxes, and observing the effects of flux fluctuations on the benthic and benthopelagic communities, require submergence facilities (i.e., vehicles, special sensors, specialized instruments)
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From page 35... ...
Novel seafloor and water column measurements and experiments, such as in situ interactive and perturbation experiments, as well as development and testing of new measurement tools, are essential and require the use of submersibles. Studies of gas hydrates in the natural environment involve the skills of a diverse community of scientists and the use of a wide range of existing and newly developing techniques.
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. The intellectual drivers for studies of evolution at hydrothermal vents and cold seeps and, by extension, other deep-sea habitats can be summarized by four questions: 1.
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From page 37... ...
Understanding the broad-scale patterns and processes of biodiversity, on the seafloor and in the water column, is one of the most challenging areas of modern deep-sea biology. Carbon Dynamics Linking Midwater and Benthic Communities A fundamental puzzle of deep-sea biology concerns the transfer of energy from the primary producers at the top of the water column to the animals that inhabit the deep seafloor below, over an average distance of 4,000m.
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From page 38... ...
Ecological Structure of Midwater Communities Between the sunlit upper layers of the open ocean and the dark floor of the deep sea is the largest living space on Earth. Within this immense midwater habitat are the planet's largest animal communities largest in terms of distribution area, numbers of individuals, and biomass.
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Gelatinous Animals and the Pelagic Food Web One of the most important discoveries by midwater researchers in recent years has been that gelatinous animals form a dominant ecological component of midwater communities worldwide (Plate 8a,b,c,d,e,f)
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A recently released National Research Council report, recognized the necessity of an ocean exploration program to identify and describe the ocean's resources. Such a program would "provide opportunities for investigating new regions and that draws on research from a variety of disciplines, would speed discovery and application of new information," including climate change predictions, beneficial new products, informed policy choices, and enhanced ocean stewardship (NRC, 2003b, p.
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143~. It is important to note that any assets required by an enhanced ocean exploration program are above and beyond those discussed and recommended in this report.
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From page 42... ...
FIXED OCEAN OBSERVATORIES Ocean Observatories Initiative In the last decade significant elements of the oceanographic research community have embraced a strategy for sustained time-series investigations, primarily to unclerstanct temporal variability and causality in Earth and ocean processes. In deep submergence science this trenc!
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