ABSTRACT:

There is a growing need to assess long-term impacts of active remediation strategies on treated aquifers. A variety
of biogeochemical alterations can result from interactions of the amendment with the aquifer, conceivably
leading to a geophysical signal associated with the long-term alteration of an aquifer. This concept of postremediation
geophysical assessment was investigated in a shallow, chlorinated solvent-contaminated aquifer
six to eight years after amendment delivery. Surface resistivity imaging and cross-borehole resistivity and
induced polarization (IP) imaging were performed on a transect that spanned treated and untreated zones of the
aquifer. Established relationships between IP parameters and surface electrical conductivity were used to predict
vertical profiles of electrolytic conductivity and surface conductivity from the inverted cross-borehole images.
Aqueous geochemistry data, along with natural gamma and magnetic susceptibility logs, were used to constrain
the interpretation. The electrical conductivity structure determined from surface and borehole imaging was
foremost controlled by the electrolytic conductivity of the interconnected pore space, being linearly related to
fluid specific conductance. The electrolytic conductivity (and thus the conductivity images alone) did not
discriminate between treated and untreated zones of the aquifer. In contrast, inverted phase angles and surface
conductivities did discriminate between treated and untreated zones of the aquifer, with the treated zone being
up to an order of magnitude more polarizable in places. Supporting aqueous chemistry and borehole logging
datasets indicate that this geophysical signal from the long-term impact of the remediation on the aquifer is most
likely associated with the formation of polarizable, dispersed iron sulfide minerals.

ABSTRACT:

This database contains measurements and datasets acquired in Caribou Bog, ME, USA, over a 21 year period. Most of this work was supported by a sequence of grants from Hydrologic Sciences program of the National Science Foundation (NSF). The datasets were acquired to investigate peatland hydrology and methane cycling in this ombotrophic peatland. The datasets include coring, hydrological and aqueous chemistry measurements, geophysical measurements and methane chamber flux measurements. Data included in this database have been reported in a series of publications by the authors of this resource spanning from 2002-2020. The database will continue to evolve as work on Caribou Bog continues by the collaborators. The database includes a set of QGIS files that can be used to help visualize many elements of the database.

The extensive files and datasets are organized into folders based around key types of data. The entire set of folders for each dataset is uploaded as a single ZIP file. Users should download the large zip files and extract the folders/subfolders into a master directory. QGIS files are provided to assist with visualizing many of the datatypes in the database.

ABSTRACT:

This composite resource includes datasets from three published studies on ebullition of methane from peatlands and tidal wetlands resulting from work performed on the following National Science Foundation (NSF) project: "EAR 1623895: Collaborative Research: Towards a mechanistic prediction of methane ebullition fluxes from northern peatlands". The resource is organized into three subdirectories corresponding to the three papers. Each subdirectory contains a URL to the publication, along with the raw datafiles for all figures containing data in each publication. Water levels reported in Chen et al. (2017) were derived from the database maintained by the Meadowlands Environmental Research Institute (link provided). All other datasets are original to this resource.