Research Chemist
Woods Hole Coastal and Marine Science Center
Email:
jpohlman@usgs.gov
Office Phone:
508-457-2213
ORCID:
0000-0002-3563-4586
Location
Crawford Building
384 Woods Hole Road
Woods Hole
, MA
02543-1598
US
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Natural cave passages penetrating a coastal aquifer in the Yucatan Peninsula (Mexico) were accessed to test the hypothesis that chemoclines associated with salinity gradients (haloclines) within the flooded cave networks of the karst subterranean estuary are sites of methane oxidation. Two field trips were carried out to the fully-submerged cave system located 6.6 km inland from the coastline in January 2015 and January 2016. Vertical chemical profiles across the water column haloclines were obtained using the OctoPiPi (OPP), a high-resolution water sampler built by the U.S. Geological Survey (USGS). The sampling efforts resulted in cm-scale profiles of major ions (e.g., chloride and sulfate), as well as concentrations...
Categories: Data;
Tags: Cenote Bang,
Ecology,
Geochemistry,
Hydrology,
Mexico, All tags...
Ox Bel Ha Cave System,
Quintana Roo,
U.S. Geological Survey,
USGS,
Yucatan Peninsula,
anchialine ecosystem,
aquatic ecosystem,
biogeochemical cycling,
biogeochemical cycling,
carbon cycling,
carbon isotope analysis,
cave,
cenote,
chemical records,
coastal aquifer,
coastal ecosystems,
ecosystem function,
environment,
environment,
estuarine ecosystems,
estuarine mixing,
field inventory and monitoring,
freshwater ecosystems,
geochemical data,
geochemistry,
groundwater,
hydrogeology,
hydrologic records,
hydrology,
inland waters,
inlandWaters,
karst,
salinity,
subterranean estuary, Fewer tags
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Subterranean estuaries extend inland into density-stratified coastal carbonate aquifers that contain a surprising diversity of endemic animals (mostly crustaceans) within a highly oligotrophic environment. How complex ecosystems thrive in this globally-distributed, cryptic habitat (termed anchialine) is poorly understood. The northeastern margin of the Yucatan Peninsula contains over 250 km of mapped, diver-accessible caves passages where previous studies have suggested chemoautotrophic processes are the source of carbon and energy sustaining the anchialine food web. This dataset, collected during four field events during U.S. Geological Survey (USGS) Coastal and Marine Geology Program Field Activities 2015-013-FA...
Categories: Data;
Types: Citation;
Tags: Cenote Bang,
Mexico,
Ox Bel Ha Cave System,
Quintana Roo, Mexico,
Yucatan Peninsula, All tags...
anchialine,
aquatic ecosystems,
biogeochemical cycling,
cave,
coastal aquifer,
ecosystem functions,
environment,
geochemistry,
inlandWaters,
karst,
sonde data, Fewer tags
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Assessment of geochemical cycling within tidal wetlands and measurement of fluxes of dissolved and particulate constituents between wetlands and coastal water bodies are critical to evaluating ecosystem function, service, and status. The U.S. Geological Survey and collaborators collected surface water and porewater geochemical data from a tidal wetland located on the eastern shore of Sage Lot Pond in Mashpee, Massachusetts, within the Waquoit Bay National Estuarine Research Reserve, between 2012 and 2019. Additional porewater geochemical and field data from a tidal wetland on the eastern shore of Great Pond in East Falmouth, MA are also included. These data can be used to evaluate biogeochemical conditions and cycling...
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A discrete sample introduction module (DSIM) was developed and interfaced to a cavity ring-down spectrometer to enable measurements of methane and CO2 concentrations and 13C values with a commercially available cavity ring-down spectrometer (CRDS). The DSIM-CRDS system permits the analysis of limited volume (5 - 100-ml) samples ranging six orders-of-magnitude from 100% analyte to the lower limit of instrument detection (2 ppm). We demonstrate system performance for methane by comparing concentrations and 13C results obtained by the DSIM and traditional methods for a variety of sample types, including low concentration (nanomolar) seawater and high concentration (> 90%) natural gas. The expansive concentration range...
Categories: Data;
Tags: Geochemistry,
Temperate Northern Atlantic,
Temperate Northern Pacific,
U.S. Geological Survey,
USGS, All tags...
biogeochemistry,
carbon cycle,
carbon cycling,
carbon dioxide,
carbon isotope analysis,
cavity ring-down spectroscopy,
eastern continental margin of India,
environment,
gas hydrate resources,
geochemical data,
geochemistry,
geochemistry,
isotope geochemistry,
marine chemistry,
methane,
methane hydrate,
northern Cascadia margin,
northern US Atlantic margin,
ocean characteristics,
oceanography,
oceans,
sediment geochemistry,
stable isotopes, Fewer tags
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A critical question for assessing global greenhouse gas budgets is how much of the methane that escapes from seafloor cold seep sites to the overlying water column eventually crosses the sea-air interface and reaches the atmosphere. The issue is particularly important in Arctic Ocean waters since rapid warming there increases the likelihood that gas hydrate--an ice-like form of methane and water stable at particular pressure and temperature conditions within marine sediments--will break down and release its methane to the overlying ocean. Some researchers have even proposed the possibility of an Arctic methane catastrophe characterized by wholesale breakdown of gas hydrates in marine sediments and release of the...
Categories: Data;
Tags: Arctic Ocean,
Norway,
Prins Karls Forland,
Spitsbergen,
Svalbard, All tags...
carbon cycling,
carbon isotope analysis,
environment,
geoscientificInformation,
greenhouse gas flux,
marine chemistry,
methane seep,
ocean temperature,
ocean-atmosphere interaction,
oceanographic observations,
oceans,
sea-air gas flux,
seep and vent ecosystems,
seepage studies, Fewer tags
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