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Millenial-Aged Organic Carbon Subsidies To A Modern River Food Web, Steven T. Petsch, J. J. Cole, P. Raymond, J. E. Bauer, N. Caraco
Millenial-Aged Organic Carbon Subsidies To A Modern River Food Web, Steven T. Petsch, J. J. Cole, P. Raymond, J. E. Bauer, N. Caraco
Steven T. Petsch
Recent studies indicate that highly aged material is a major component of organic matter transported by most rivers. However, few studies have used natural 14C to trace the potential entry of this aged material into modern river food webs. Here we use natural abundance 14C, 13C, and deuterium (2H) to trace the contribution of aged and contemporary organic matter to an important group of consumers, crustacean zooplankton, in a large temperate river (the Hudson River, New York, USA). Zooplankton were highly 14C depleted (mean delta14C = -240 per thousand) compared to modern primary production in the river or its watershed …
Impact Of Hurricane Katrina (2005) On Shelf Organic Carbon Burial And Deltaic Evolution, Steven T. Petsch, Mead A. Allison, Timothy M. Dellapenna, Elizabeth S. Gordon, Siddhartha Mitra
Impact Of Hurricane Katrina (2005) On Shelf Organic Carbon Burial And Deltaic Evolution, Steven T. Petsch, Mead A. Allison, Timothy M. Dellapenna, Elizabeth S. Gordon, Siddhartha Mitra
Steven T. Petsch
Sediment cores from the continental shelf adjacent to the Mississippi River delta immediately after the passage of Hurricane Katrina were used to examine the magnitude, and implications for the carbon budget, of sediment and particulate organic carbon (POC) remobilized by the storm on the river-dominated continental shelf. POC was sourced from incision of the innermost continental shelf (<25 m water depth) and from surge ebb advection from adjacent wetlands and shallow estuaries, and was re-deposited in deeper water on the shelf. This pulse of young (<1,600 yBP) labile POC, mixed with relict (>5000 yBP) POC eroded from the seafloor, has major implications for the remineralization versus burial of POC in deltas. The scale of erosional deflation of the shelf in water depths beyond seasonal wave-current conditions suggests that, over millennia, tropical cyclones may be …
Linking Lithology And Land Use To Sources Of Dissolved And Particulate Organic Matter In Headwaters Of A Temperate, Passive-Margin River System, Steven T. Petsch, B. E. Longwortha, P. A. Raymond, J. E. Bauerc
Linking Lithology And Land Use To Sources Of Dissolved And Particulate Organic Matter In Headwaters Of A Temperate, Passive-Margin River System, Steven T. Petsch, B. E. Longwortha, P. A. Raymond, J. E. Bauerc
Steven T. Petsch
A number of rivers have been found to transport highly aged organic matter [OM]; however, the sources of this aged material remain a matter of debate. One potential source may be erosion and weathering of headwater lithologies rich in ancient sedimentary OM. In this study, waters, suspended particulates, streambed sediments, rocks and soils from fourteen small headwater watersheds of a mid-size, temperate, passive margin river were sampled and characterized by Δ14C, δ13C, and POC/TPN ratios to identify sources of particulate and dissolved OM delivered to the river mainstem. These headwater sites encompass a range in lithology (OM-rich shales, OM-lean carbonate/mudstone …
Salinity Constraints On Subsurface Archaeal Diversity And Methanogenesis In Sedimentary Rock Rich In Organic Matter, Steven T. Petsch, P. Waldron, A. M. Martini, K. Nüsslein
Salinity Constraints On Subsurface Archaeal Diversity And Methanogenesis In Sedimentary Rock Rich In Organic Matter, Steven T. Petsch, P. Waldron, A. M. Martini, K. Nüsslein
Steven T. Petsch
The diversity of microorganisms active within sedimentary rocks provides important controls on the geochemistry of many subsurface environments. In particular, biodegradation of organic matter in sedimentary rocks contributes to the biogeochemical cycling of carbon and other elements and strongly impacts the recovery and quality of fossil fuel resources. In this study, archaeal diversity was investigated along a salinity gradient spanning 8 to 3,490 mM Cl− in a subsurface shale rich in CH4 derived from biodegradation of sedimentary hydrocarbons. Shale pore waters collected from wells in the main CH4-producing zone lacked electron acceptors such as O2, NO3−, Fe3+, or SO42−. Acetate …
A Solid State 13c Nmr Study Of Kerogen Degradation During Black Shale Weathering, Steven T. Petsch, R. J. Smernik, T. I. Eglinton, J. M. Oades
A Solid State 13c Nmr Study Of Kerogen Degradation During Black Shale Weathering, Steven T. Petsch, R. J. Smernik, T. I. Eglinton, J. M. Oades
Steven T. Petsch
Solid state 13C nuclear magnetic resonance (NMR) spectroscopy is used to examine kerogen composition in weathering profiles of the Monterey, Green River, Woodford, and New Albany formations. Techniques include cross polarization (CP) and Bloch decay (BD) spectral acquisition, dipolar dephasing (DD), spin counting, experiments to provide estimates of relaxation times (T1ρH and T1H), and proton spin relaxation editing (PSRE). It is demonstrated that CP/MAS (cross polarization/magic angle spinning) spectra obtained on isolated kerogens provide reliable characterization of kerogen composition (compared with BD spectra and whole-rock samples). Highly aliphatic (polymethylenic) kerogens are not appreciably altered during weathering. Aromatic and/or branched aliphatic …