Stanford Oceans Seminar Series

OCEANS SEMINAR 2006-2007
The Seminar for 2006-2007 is held on Tuesdays in Bldg. 320, Room 105 at 3:30 pm

Oceans Seminar Archive: 2005-2006 2004-2005 2003-2004 2002-2003 2001-2002

April 3, 2007

Derek Vance

Department of Earth Sciences, University of Bristol

Trace metal cycling in the oceans:

new insights from trace metal isotope systematics

Stable isotope measurements of the "light" elements - carbon, oxygen, nitrogen, sulphur - have revolutionised our understanding of many aspects of the Earth system - not least the cycling of these elements between the biosphere, ocean and atmosphere. This seminar will introduce a novel set of isotopic tracers that are just being developed and that potentially shed similar light on trace metal biogeochemical cycling. Though these tracers are in the very early stages of development these is significant hope that they will, for example, illuminate the behaviour of trace metals in HNLC zones both now and in the past, with implications for the operation of the biological pump and sequestration of atmospheric CO₂ by the oceans. I will present data from culture experiments showing how diatom usage of inorganic Zn leads to measurable isotopic fractionations and I will relate these experiments to water column measurements in the NE Pacific HNLC zone. Isotopic data for Cu, on the other hand, are consistent with a relatively simple dissolved chemistry, with the isotopic composition largely determined by isotopic partitioning between organic ligands and particulate matter.

April 10, 2007

Barbara Sherwood Lollar
Professor and Director, Stable Isotope Laboratory, University of Toronto

Tracers in the Deep: Hydrogeologic Controls on Release of H2 Energy for Deep Subsurface Life

The hypothesis that extinct or extant life elsewhere in the solar system may be chemoautotrophic, in contrast to the primary photosynthetic basis for life on Earth, has prompted recent research into Earth ecosystems where chemosynthetic microbial communities thrive. Recent studies have focused on hot springs, caves, deep sea hydrothermal vents and basalt aquifers where H2 autotrophic communities have been identified. In this talk, dissolved H2 concentrations up to the mM range and H2 levels up to 9-58% by volume in the free gas phase are reported for ground waters at sites in the Precambrian Shields of Canada, South Africa and Finland. In these geologically old, hydrogeologically isolated environments where extensive water-rock reactions have produced high salinities through rock-mineral leaching, mM concentrations of dissolved H2 originate from variety of geologic processes. Both serpentinization and radiolytic decomposition of water will be discussed as possible mechanisms of H2 production. Deep Precambrian Shield fracture waters contain some of the highest levels of dissolved H2 ever reported and represent a potentially important energy-rich environment for subsurface microbial life. The hydrogeologically isolated nature of these fracture-controlled ground water systems provides a mechanism for the products of water-rock interaction to accumulate over geologic time scales, producing correlations between high H2 levels, abiogenic hydrocarbon signatures, and the high salinities and highly altered δ18O and δ2H values of these ground waters. A conceptual model is presented that demonstrates how periodic opening of fractures and resulting chemical disequilibrium and mixing controls the distribution and supply of H2, and supports deep subsurface microbial communities of H2-utilizing sulfate reducers and methanogens.

April 17, 2007

Philippe Tortell
Department of Earth and Ocean Science, University of British Columbia

Fine-scale distribution of biogenic gases in the Ross Sea: Implications for phytoplankton physiology and ecology.

April 24, 2007

Mark Altabet

School for Marine Science & Technology, University of Massachusetts, Dartmouth

Pliocene initiation of Eastern Tropical Pacific suboxic zones with 'turn-on' of the equatorial Walker circulation

May 1, 2007

Steve Emerson
School of Oceanography, University of Washington

May 8, 2007

Sara E. Mikaloff-Fletcher

Research Associate Biogeochemist, Princeton University

Air-sea Fluxes of Natural, Anthropogenic, and Contemporary CO₂

Earth's oceans are believed to be the largest net sink of anthropogenic CO₂, taking up an average of 2.1 ± 0.2 Pg C yr^-1 between 1992 and 1996. While the global oceanic carbon uptake is relatively well known, there are substantial gaps in our understanding of the spatial pattern, variability, and driving mechanisms of this flux. The contemporary air-sea flux of CO₂ can be broken down into two primary components: the exchange of natural CO₂ that existed in preindustrial times and the uptake of anthropogenic CO₂, which is driven by the perturbation of atmospheric CO₂ from fossil fuel burning, cement production, and land use change. We use inverse methods to estimate separately air-sea fluxes of natural and anthropogenic CO₂ using observations of dissolved inorganic carbon and other tracers and Ocean General Circulation Models (OGCMs). The flux estimates imply substantial natural carbon uptake at mid-latitudes. This carbon is transported equator-ward to the tropics or pole-ward into the Southern Ocean, where there is substantial natural carbon out-gassing. Conversely, there is vigorous uptake of anthropogenic carbon in the Southern Ocean that drives northward transport of anthropogenic carbon throughout the southern hemisphere.
May 15, 2007
Jim Bishop

  

  
EO Lawrence Berkeley National Laboratory
May 22, 2007

TBA

May 29, 2007

Howie Scher

UC Santa Cruz

January 16, 2007

Ruth Blake
Yale University
Biogeochemistry of the Deep Biosphere

January 30, 2007

Christopher Scholin
Monterey Bay Aquarium Research Institute
The Environmental Sample Processor (ESP): A Robotic Instrument for Applying Molecular Probe Technology Remotely Under the Sea

February 13, 2007

Kay Bidle
Rutgers University
A fate for phytoplankton in the oceans: Molecular mechanisms regulating mortality and channeling productivity to microbial foodwebs

February 20, 2007

Katrina Edwards
University of Southern California
Microbiologically Mediated Rock Weathering - At and Below the Seafloor

February 27, 2007

Brad Bebout
NASA Ames Research Center
Nitrogen cycling in hypersaline microbial mats

March 6, 2007

Brad Tebo
Oregon Health & Science University, OGI School of Science and Engineering
Geomicrobiology of manganese(II) oxidation

March 13, 2007

Matthew McCarthy
University of California, Santa Cruz
Compound-specific amino acid isotopes as metabolic signatures for tracing sources of organic nitrogen

October 10, 2006

TBA

October 17, 2006

Julie McClean
Lawrence Livermore National Laboratory and Scripps Institute of Oceanography
Towards a fine-resolution Community Climate System Model (CCSM)

October 24, 2006

Thomas Church
University of Delaware, Graduate College of Marine Studies
Source and fate of trace elements in the Sargasso Sea

October 31, 2006

Rachel Haymon
University of California at Santa Barbara
Effects of hot spots on mid-ocean ridge volcanic-hydrothermal systems: Results of the 2005-2006 Galapagos expedition

November 7, 2006

Matt Charette
Woods Hole Oceanographic Institute
The role of subterranean estuaries and submarine groundwater discharge in the oceanic mass balance of trace metals and nutrients

November 14, 2006

Joe Needoba
Monterey Bay Aquarium Research Institute
The Land-Ocean Biogeochemical Observatory in Elkhorn Slough, CA

November 21, 2006

Thanksgiving Break
No seminar this week!

November 28, 2006

Ariel Anbar
Arizona State University
Use of molybdenum isotopes to study changes in the oxygen content of the oceans through time

December 5, 2006

Geoff Shester
Interdisciplinary Program in Environment and Resources, Stanford University
Fisheries economics and marine ecology
For questions concerning the seminar, contact Matthew Long
mclong AT stanford.edu
Directions to the School of Earth Sciences

Other Ocean Science Related Seminars in the Bay Area:
Carnegie Global Ecology Seminars
Hopkins Marine Stations Seminars
Monterey Bay Aquarium Research Institute (MBARI) Seminars
UC Santa Cruz Ocean Sciences Seminar Series
UC Berkeley Earth & Planetary Sciences Department Seminars
USGS Western Region Calendar of Events
Peninsula Geological Society

April 3, 2007	Derek Vance Department of Earth Sciences, University of Bristol Trace metal cycling in the oceans: new insights from trace metal isotope systematics Stable isotope measurements of the "light" elements - carbon, oxygen, nitrogen, sulphur - have revolutionised our understanding of many aspects of the Earth system - not least the cycling of these elements between the biosphere, ocean and atmosphere. This seminar will introduce a novel set of isotopic tracers that are just being developed and that potentially shed similar light on trace metal biogeochemical cycling. Though these tracers are in the very early stages of development these is significant hope that they will, for example, illuminate the behaviour of trace metals in HNLC zones both now and in the past, with implications for the operation of the biological pump and sequestration of atmospheric CO₂ by the oceans. I will present data from culture experiments showing how diatom usage of inorganic Zn leads to measurable isotopic fractionations and I will relate these experiments to water column measurements in the NE Pacific HNLC zone. Isotopic data for Cu, on the other hand, are consistent with a relatively simple dissolved chemistry, with the isotopic composition largely determined by isotopic partitioning between organic ligands and particulate matter.
April 10, 2007	Barbara Sherwood Lollar Professor and Director, Stable Isotope Laboratory, University of Toronto Tracers in the Deep: Hydrogeologic Controls on Release of H2 Energy for Deep Subsurface Life The hypothesis that extinct or extant life elsewhere in the solar system may be chemoautotrophic, in contrast to the primary photosynthetic basis for life on Earth, has prompted recent research into Earth ecosystems where chemosynthetic microbial communities thrive. Recent studies have focused on hot springs, caves, deep sea hydrothermal vents and basalt aquifers where H2 autotrophic communities have been identified. In this talk, dissolved H2 concentrations up to the mM range and H2 levels up to 9-58% by volume in the free gas phase are reported for ground waters at sites in the Precambrian Shields of Canada, South Africa and Finland. In these geologically old, hydrogeologically isolated environments where extensive water-rock reactions have produced high salinities through rock-mineral leaching, mM concentrations of dissolved H2 originate from variety of geologic processes. Both serpentinization and radiolytic decomposition of water will be discussed as possible mechanisms of H2 production. Deep Precambrian Shield fracture waters contain some of the highest levels of dissolved H2 ever reported and represent a potentially important energy-rich environment for subsurface microbial life. The hydrogeologically isolated nature of these fracture-controlled ground water systems provides a mechanism for the products of water-rock interaction to accumulate over geologic time scales, producing correlations between high H2 levels, abiogenic hydrocarbon signatures, and the high salinities and highly altered δ18O and δ2H values of these ground waters. A conceptual model is presented that demonstrates how periodic opening of fractures and resulting chemical disequilibrium and mixing controls the distribution and supply of H2, and supports deep subsurface microbial communities of H2-utilizing sulfate reducers and methanogens.
April 17, 2007	Philippe Tortell Department of Earth and Ocean Science, University of British Columbia Fine-scale distribution of biogenic gases in the Ross Sea: Implications for phytoplankton physiology and ecology.
April 24, 2007	Mark Altabet School for Marine Science & Technology, University of Massachusetts, Dartmouth Pliocene initiation of Eastern Tropical Pacific suboxic zones with 'turn-on' of the equatorial Walker circulation
May 1, 2007	Steve Emerson School of Oceanography, University of Washington
May 8, 2007	Sara E. Mikaloff-Fletcher Research Associate Biogeochemist, Princeton University Air-sea Fluxes of Natural, Anthropogenic, and Contemporary CO₂ Earth's oceans are believed to be the largest net sink of anthropogenic CO₂, taking up an average of 2.1 ± 0.2 Pg C yr^-1 between 1992 and 1996. While the global oceanic carbon uptake is relatively well known, there are substantial gaps in our understanding of the spatial pattern, variability, and driving mechanisms of this flux. The contemporary air-sea flux of CO₂ can be broken down into two primary components: the exchange of natural CO₂ that existed in preindustrial times and the uptake of anthropogenic CO₂, which is driven by the perturbation of atmospheric CO₂ from fossil fuel burning, cement production, and land use change. We use inverse methods to estimate separately air-sea fluxes of natural and anthropogenic CO₂ using observations of dissolved inorganic carbon and other tracers and Ocean General Circulation Models (OGCMs). The flux estimates imply substantial natural carbon uptake at mid-latitudes. This carbon is transported equator-ward to the tropics or pole-ward into the Southern Ocean, where there is substantial natural carbon out-gassing. Conversely, there is vigorous uptake of anthropogenic carbon in the Southern Ocean that drives northward transport of anthropogenic carbon throughout the southern hemisphere.
May 15, 2007	Jim Bishop EO Lawrence Berkeley National Laboratory
May 22, 2007	*TBA*
May 29, 2007	Howie Scher UC Santa Cruz
January 16, 2007		Ruth Blake Yale University Biogeochemistry of the Deep Biosphere
January 30, 2007		Christopher Scholin Monterey Bay Aquarium Research Institute The Environmental Sample Processor (ESP): A Robotic Instrument for Applying Molecular Probe Technology Remotely Under the Sea
February 13, 2007		Kay Bidle Rutgers University A fate for phytoplankton in the oceans: Molecular mechanisms regulating mortality and channeling productivity to microbial foodwebs
February 20, 2007		Katrina Edwards University of Southern California Microbiologically Mediated Rock Weathering - At and Below the Seafloor
February 27, 2007		Brad Bebout NASA Ames Research Center Nitrogen cycling in hypersaline microbial mats
March 6, 2007		Brad Tebo Oregon Health & Science University, OGI School of Science and Engineering Geomicrobiology of manganese(II) oxidation
March 13, 2007		Matthew McCarthy University of California, Santa Cruz Compound-specific amino acid isotopes as metabolic signatures for tracing sources of organic nitrogen
October 10, 2006		*TBA*
October 17, 2006		Julie McClean Lawrence Livermore National Laboratory and Scripps Institute of Oceanography Towards a fine-resolution Community Climate System Model (CCSM)
October 24, 2006		Thomas Church University of Delaware, Graduate College of Marine Studies Source and fate of trace elements in the Sargasso Sea
October 31, 2006		Rachel Haymon University of California at Santa Barbara Effects of hot spots on mid-ocean ridge volcanic-hydrothermal systems: Results of the 2005-2006 Galapagos expedition
November 7, 2006		Matt Charette Woods Hole Oceanographic Institute The role of subterranean estuaries and submarine groundwater discharge in the oceanic mass balance of trace metals and nutrients
November 14, 2006		Joe Needoba Monterey Bay Aquarium Research Institute The Land-Ocean Biogeochemical Observatory in Elkhorn Slough, CA

November 21, 2006		Thanksgiving Break No seminar this week!
November 28, 2006		Ariel Anbar Arizona State University Use of molybdenum isotopes to study changes in the oxygen content of the oceans through time
December 5, 2006		Geoff Shester Interdisciplinary Program in Environment and Resources, Stanford University Fisheries economics and marine ecology