Images

After releasing sediment into the top of a settling tube filled with water, a pan and microbalance collects and weighs the sediment as it slowly reaches the bottom of the tube. A computer records the cumulative sediment weight over time, as well as how long it took each particle to reach the pan.

In the cold storage room at the USGS Pacific Coastal and Marine Science Center, we store cores on large racks that can hold about 4,500 full sized cores or D-tubes with split cores, up to 1.5 meters long.

These track-mounted racks pack together to save space. Cranking a handle moves the aisle between racks for core access.

The back door of the refrigerator connects to our core and sample processing labs.

Each half of a split sediment core is wrapped in plastic to prevent drying and contamination. For long-term storage, we can shrink-wrap one half with a thick film that prevents moisture loss.

Lab technicians create written descriptions of sediment cores, referencing Munsell chart colors and standard phrases.

Sediment cores may be subsampled for further processing and analysis in other labs, like the Sediment Lab which is across the hall from the Core Lab.

The first stop for many sediment cores is the Geotek MSCL or multi-sensor core logger. The logger automatically measures P-wave velocity, magnetic susceptibility, electrical resistivity, and gamma density at intervals from 1 millimeter to 1 centimeter along cores up to 1.5 meters long.

This is the Pacific Coastal and Marine Science Center's Sediment Prep Lab, where sediment samples and core subsamples are prepared for analyses.

Our fume hood lab allows for sample preparation in safe conditions.

The Micromeritics Sedigraph III uses X-rays to automatically analyze settling times for sediment sizes between 300 microns and 0.1 microns (2 phi to 13 phi).

In the core lab, the Geotek core splitter cuts sediment cores in half lengthwise using oscillating saws and a wire cutter.

We spin down a sample of sediment that's mixed with distilled water in a centrifuge. This separates the sediment from the water at the bottom of the sample bottle, and we pour off most of the water. This process removes dissolved salts.

For some projects, scientists want to calculate sediment settling velocity and need to measure particle size using gravity. We use custom-built settling tubes filled with water – three at 2 meters tall (like the one shown here) and one 3 meters tall.

In the carbon analysis laboratory, these three instruments (the UIC CM250) automatically analyze the total carbon, total organic carbon, and total inorganic carbon content of multiple dried sediment samples. 

This Dionex ASE 350 accelerated solvent extractor automatically extracts hydrocarbons for further analysis. We also have a Zymark TurboVap II for sample preparation (not shown).

Andrew Stevens runs a personal watercraft rigged with sonar and precision GPS to survey northern Monterey Bay, California.

Alex Snyder (left) and SeanPaul La Selle stay in radio contact with a personal watercraft operator offshore in order to provide supplies and safety near Moss Landing, California. 

The refrigerated sample repository of the USGS Pacific Coastal and Marine Science Center in Santa Cruz, CA includes easily accessible shelving space which can store thousands of samples.

Gerry Hatcher (left) and Shawn Harrison adjust a computer controlling video cameras on the roof of the Dream Inn, a 10-story hotel overlooking Monterey Bay in Santa Cruz, California. Harrison uses the images to improve understanding and computer modeling of beach processes. 

Dan Hoover takes a break near Moss Landing, California. Dan drives the all-terrain vehicle seen behind him to rapidly survey long sections of beach using precision GPS.