A5086337448- Methane Hydrates and Related Phenomena
- Geology and Paleoclimatology Research
- Atmospheric and Environmental Gas Dynamics
- Marine and coastal ecosystems
- Ocean Acidification Effects and Responses
- Oceanographic and Atmospheric Processes
- Hydrocarbon exploration and reservoir analysis
- Marine Biology and Ecology Research
- Global Energy and Sustainability Research
- Isotope Analysis in Ecology
- Paleontology and Stratigraphy of Fossils
- Geological Studies and Exploration
- Atmospheric chemistry and aerosols
- Arctic and Antarctic ice dynamics
- Climate variability and models
- Climate change and permafrost
- Cryospheric studies and observations
- Climate Change Policy and Economics
- Science and Climate Studies
- Atmospheric Ozone and Climate
- Analytical Chemistry and Sensors
- Geological formations and processes
- Geochemistry and Geologic Mapping
- Marine Bivalve and Aquaculture Studies
- Coastal and Marine Management
University of Chicago
2011-2020
University of British Columbia
2020
University of California, Berkeley
2020
Stanford University
2020
EarthTech International (United States)
2020
Alberta Oil Sands Technology and Research Authority
2020
Northern Great Plains Research Laboratory
2020
Agricultural Research Service
2020
University of Illinois Chicago
2005-2013
Geophysical Laboratory
2013
A coral reef represents the net accumulation of calcium carbonate (CaCO 3 ) produced by corals and other calcifying organisms. If calcification declines, then reef-building capacity also declines. Coral depends on saturation state mineral aragonite surface waters. By middle next century, an increased concentration carbon dioxide will decrease in tropics 30 percent biogenic precipitation 14 to percent. reefs are particularly threatened, because organisms secrete metastable forms CaCO , but...
CO 2 released from combustion of fossil fuels equilibrates among the various carbon reservoirs atmosphere, ocean, and terrestrial biosphere on timescales a few centuries. However, sizeable fraction remains in awaiting return to solid earth by much slower weathering processes deposition CaCO 3 . Common measures atmospheric lifetime , including e-folding time scale, disregard long tail. Its neglect calculation global warming potentials leads many underestimate longevity anthropogenic warming....
We compiled and standardized sediment trap data below 1000 m depth from 52 locations around the globe to infer implications of Armstrong et al. [2002] “ballast” model ratio organic carbon calcium carbonate in deep sea (the rain ratio). distinguished three forms mineral ballast: carbonate, opal, lithogenic material. concur with that sinking fluxes correlate tightly fluxes. Based on correlations seen data, we conclude most is carried by because it denser than opal more abundant terrigenous...
A model of the ocean and seafloor carbon cycle is subjected to injection new CO 2 pulses varying sizes estimate resident atmospheric fraction over coming 100 kyr. The used separate processes air‐sea equilibrium, an temperature feedback, CaCO 3 compensation, silicate weathering on residual anthropogenic pCO in atmosphere at 1, 10, mean lifetime dominated by long tail, resulting a range 30–35 fossil fuel release implies that climate perturbation may have time interact with ice sheets, methane...
A Change in the Air? Between around 1.2 million and 500,000 years ago, Earth's glacial cycle changed from one with a period of roughly 40,000 to about 100,000 years. Although there has been much speculation why this transition may have occurred, no potential explanation seemed more likely than that it was caused by decreasing concentrations atmospheric CO 2 . Hönisch et al. (p. 1551 ) present record p for past 2.1 years, derived boron isotopic composition planktonic foraminifera, show amount...
Fifteen years after the discovery of major glacial/interglacial cycles in CO 2 concentration atmosphere, it seems that all simple mechanisms for lowering p have been eliminated. We use a model ocean and sediment geochemistry, which includes new developments iron limitation biological production at sea surface anoxic diagenesis its effect on CaCO 3 preservation sediments, to evaluate current proposals explaining within context carbon cycle. After equilibration with is unable generate glacial...
Abstract Multimillennial simulations with a fully coupled climate–carbon cycle model are examined to assess the persistence of climatic impacts anthropogenic CO2 emissions. It is found that time required absorb strongly depends on total amount emissions; for emissions similar known fossil fuel reserves, 50% more than 2000 yr. The long-term climate response appears be independent rate at which emitted over next few centuries. Results further suggest lifetime surface air temperature anomaly...
We present a model of the global methane inventory as hydrate and bubbles below sea floor. The predicts CH(4) in ocean today to be approximately 1600-2,000 Pg C. Most is Pacific, large part because lower oxygen levels enhance preservation organic carbon. Because concentration may different from long-term average, sensitivity O(2) source uncertainty predicting inventories. Cold water column temperatures high latitudes lead buildup hydrates Arctic Antarctic at shallower depths than possible...
The notion is pervasive in the climate science community and public at large that impacts of fossil fuel CO2 release will only persist for a few centuries. This conclusion has no basis theory or models atmosphere/ocean carbon cycle, which we review here. largest fraction recovery take place on time scales centuries, as invades ocean, but significant CO2, ranging published literature from 20–60%, remains airborne thousand years longer. Ultimate takes hundreds thousands years, geologic...
Abstract. Methane frozen into hydrate makes up a large reservoir of potentially volatile carbon below the sea floor and associated with permafrost soils. This intuitively seems precarious, because ice floats in water, melts at Earth surface conditions. The is so that if 10% methane were released to atmosphere within few years, it would have an impact on Earth's radiation budget equivalent factor 10 increase atmospheric CO2. Hydrates are releasing today response anthropogenic warming, for...
The long term abiological sinks for anthropogenic CO 2 will be dissolution in the oceans and chemical neutralization by reaction with carbonates basic igneous rocks. We use a detailed ocean/sediment carbon cycle model to simulate response of carbonate ocean range release scenarios. CaCO 3 play only secondary role buffering concentration atmosphere because uptake capacity kinetics are limited dynamics cycle. Dissolution into water sequesters 70–80% on time scale several hundred years....
A detailed model of the ocean circulation and carbon cycle was coupled to a mechanistic CaCO 3 diagenesis in deep sea sediments simulate millennium‐scale response oceans future fossil fuel CO 2 emissions atmosphere sea. Simulations injection show that dissolution is sensitive passage high‐CO waters through Atlantic Ocean, but has negligible impact on atmospheric p or stabilization emission coming centuries. The ultimate fate will be react with seafloor land. An initial spike reverses net...
Gridded maps of sediment calcium carbonate (calcite) concentration and overlying water saturation state [ Archer , 1996] are combined with benthic oxygen fluxes accumulation rates from Jahnke [1996] Cweink [1986] to drive a diagenetic model preservation in deep‐sea sediments. The only input for which we cannot draw detailed map is the rain rate calcite seafloor, so I use calculate required simulate observed distribution on seafloor. predictive power can be checked by searching parameters...
We use an Earth system model of intermediate complexity, CLIMBER‐2, to investigate what recent improvements in the representation physics and biology glacial ocean imply for atmospheric concentration. The coupled atmosphere‐ocean under boundary conditions is able reproduce deep, salty, stagnant water mass inferred from Antarctic deep pore data changing temperature entire ocean. When carbonate compensation included model, we find a CO 2 drawdown 43 ppmv associated mainly with shoaling...
Historical observations of the concentration calcium carbonate in global deep sea sediments are compiled and compared with a new gridded field seawater CO 3 = to reveal regional variations calcite lysocline. The most obvious mode variability lysocline is thickness (defined here as difference overlying water saturation, ΔCO , between high low sediments) thicker Atlantic than Pacific. I attribute this variation differences delivery rate terriginous material. A recent model for lower glacial...
Benthic oxygen fluxes calculated from in situ microclectrode profiles are compared with benthic flux chamber O 2 uptake measurements on a transect of eight stations across the continental shelf and three slope Washington State. Station depths ranged 40 to 630 m bottom‐water concentrations were 127–38 µ M. The measured by two methods similar slope, but shelf, exceeded microelectrode as much factor 3–4. We attribute this difference pore‐water irrigation, process which apparently accounts for...
The IRONEX II in situ fertilization experiment showed decisively that availability of iron limits the growth phytoplankton equatorial Pacific surface waters. High‐nutrient low‐chlorophyll (HNLC) waters, potentially limited, are also found North and Southern Ocean. A model seawater geochemistry has been incorporated into a global ocean circulation carbon cycle tuned to match observed Fe distribution. reproduces HNLC areas Ocean but predicts nutrient depletion (a region high dust fluxes from...
A new model for three‐dimensional mesoscale flow is used to simulate the vertical transport of nutrients into euphotic zone from deeper waters. We use diagnose effects motions on upper ocean biogeochemical cycles NO 3 , CO 2 O sea surface exposure tracers that resemble dissolved organic carbon (DOC) and H corresponding rates production gas exchange in regions near Joint Global Ocean Flux Study (JGOFS) oligotrophic time series sites Hawaii Bermuda during late summer. The physical...
A chemically reactive 10‐layer sediment module was coupled to a geochemical ocean general circulation model (the Hamburg Oceanic Carbon Cycle Model). The includes four solid components (CaCO 3 , opal, organic carbon, and clay), five pore water substances (dissolved inorganic total alkalinity, PO 4 3− O 2 Si(OH) ) plus corresponding species containing 13 C 14 instead of 12 C. processes, namely, particle deposition, reactions, diffusion interaction with the open column, vertical advection,...
Sudden global warming 55 million years ago provides evidence for high climate sensitivity to atmospheric CO, but the source of carbon remains enigmatic.