Scanning electron microscope
|Created||October 30, 2019|
|Modified||February 11, 2020|
|State||Final no updates expected|
Microbial fuel cells (MFCs) were used to conduct cathodic poised potential experiments as described in Jones et al. (in preparation). After cyclic voltametry scanning of the indium tin oxide electrodes in the fuel cells at the end of the experiment, the ITO electrodes were carefully removed from the MFCs and split into two sections using a diamond scribe and tweezers for microscopy and DNA analysis. One piece was serially dehydrated in ethanol solutions (10 min steps each at 50:50, 60:40, 70:30, 80:20, 90:10 and 100:0 ratios of ethanol:distilled water) and hexamethyldisilizane (10 min) and air dried for 3 days in a HEPA-filtered biosafety cabinet in preparation for scanning electron microscopy (SEM), following methods available elsewhere (DAngelo and Orcutt, 2019). Dehydrated slide pieces were then mounted onto 12-mm-diameter SEM stubs with double-sided carbon tape, sputter coated with gold with a Denton Vacuum Desk IV cold sputter instrument (Denton Vacuum LLC, Moorestown, NJ), and imaged with a Zeiss Supra25 SEM at between 5-10 kV and a working distance between 3-9 mm.
BCO-DMO Data Manager Processing Notes:
* All images zipped into SEM_images.zip
* Imagelist made of all SEM images submitted. Imagelist matched with metadata in the tabular dataset to verify each image had metadata.
* Column of direct links to download individual images added to tabular dataset.
* Sample IDs modified to match experimental metadata as discussed with data submitter.
unique sample identification or number; any combination of alpha numeric characters; precise definition is file dependent
Experimental conditions applied to experimental units. In comparative experiments, members of the complementary group, the control group, receive either no treatment or a standard treatment.
Meters below seafloor (mbsf); convention used for depths below the seabed in geology, oceanography, petrology and ocean drilling; often used in reporting measurements made from sediment cores.
latitude, in decimal degrees, North is positive, negative denotes South; Reported in some datasets as degrees, minutes
longitude, in decimal degrees, East is positive, negative denotes West; Reported in some datsets as degrees, minutes
water depth, in meters
|Beth N. Orcutt||Bigelow Laboratory for Ocean Sciences||✓|
|Amber York||Woods Hole Oceanographic Institution (WHOI BCO-DMO)|
|Project Title||Collaborative Research: Completing North Pond Borehole Experiments to Elucidate the Hydrology of Young, Slow-Spread Crust|
|Acronym||North Pond 2017|
|Created||July 5, 2017|
|Modified||July 5, 2017|
NSF Award Abstract:
Seawater circulates through the upper part of the oceanic crust much like groundwater flows through continental aquifers. However, in the ocean this seawater circulation, many times heated by buried magmatic bodies, transports and releases 25% of the Earth's heat. The rate of fluid flow through ocean crust is estimated to be equal to the amount of water delivered by rivers to the ocean. Much of what we know of this subseafloor fluid flow comes from studies in the eastern Pacific Ocean on ocean crust created by medium and fast spreading mid-ocean ridges. These studies indicate that seawater and its circulation through the seafloor significantly impact crustal evolution and biogeochemical cycles in the ocean and affect the biosphere in ways that are just now beginning to be quantified and understood. To expand this understanding, this research focuses on fluid flow of seafloor generated by slow spreading ridges, like those in the Atlantic, Indian and Arctic Oceans because it is significantly different in structure, mineralogy, and morphology than that formed at fast and intermediate spreading ridges. This research returns to North Pond, a long-term; seafloor; fluid flow monitoring site, drilled and instumented by the Ocean Drilling Program in the Atlantic Ocean. This research site was punctured by boreholes in which fluid flow and geochemical and biological samplers have been deployed for a number of years to collect data and samples. It also provides resources for shipboard and on-shore geochemical and biological analysis. Broader impacts of the work include sensor and technology development, which increases infrastructure for science and has commercial applications. It also provides training for students and the integration of education and research at three US academic institutions, one of which is an EPSCoR state (Mississippi), and supports a PI whose gender is under-represented in sciences and engineering. Public outreach will be carried out in conjunction with the Center for Dark Energy Biosphere Investigations.
This project completes a long-term biogeochemical and hydrologic study of ridge flank hydrothermal processes on slow-spreading, 8 million year old crust on the western flank of the Mid-Atlantic Ridge. The site, North Pond, is an isolated northeast-trending sediment pond, bounded by undersea mountains that have been studied since the 1970s. During Integrated Ocean Drilling Program Expedition 336 in 2011 and an expedition five months later (2012), sensors, samplers, and experiments were deployed in four borehole observatories drilled into the seafloor that penetrated into volcanic crust, with the purpose of monitoring changes in hydrologic properties, crustal fluid composition and mineral alteration, among other objectives. Wellhead sampling in 2012 and 2014 already revealed changes in crustal fluid compositions; and associated pressure data confirm that the boreholes are sealed and overpressured, reflecting a change in the formation as the boreholes recover from drilling disturbances. This research includes a 13-day oceanographic expedition and use of on-site robotically operated vehicles to recover downhole instrument packages at North Pond. It will allow the sampling of crustal fluids, recovering pressure data, and measuring fluid flow rates. Ship- and shore-based analyses will be used to address fundamental questions related to the hydrogeology of hydrothermal processes on slow-spread crust.
|Beth N. Orcutt||Bigelow Laboratory for Ocean Sciences||Lead Principal Investigator||✓|
|Charles Geoffrey Wheat||University of Alaska Fairbanks (UAF-IMS)||Principal Investigator|
|Keir Becker||University of Miami Rosenstiel School of Marine and Atmospheric Science (UM-RSMAS)||Principal Investigator|