| Description |
The U.S. Geological Survey (USGS) deployed a sediment trap (McLane PARFLUX 78H) mooring in the northern Gulf of Mexico (27.5 °N and 90.3°W, water depth 1150 meters [m]) in January 2008 to collect seasonal time-series data on the flux and assemblage composition of planktic foraminifers. The trap was positioned in the water column at a depth of 700 m on the mooring cable to enable the collection of deeper dwelling species of planktic foraminifera. The trap contains 21 collection cups that were programmed to rotate every 7 to 14 days (resulting in weekly to biweekly sampling resolution). Upon retrieval, samples were subsequently wet split into four aliquots using a precision rotary splitter, stored in buffered deionized water, and refrigerated. A quarter split was wet sieved over a 150-micron (μm) sieve and subsequently wet picked for all foraminifers. In samples containing fewer than 300 foraminifers in the first quarter split, an additional split was processed and picked in its entirety. The counts were then summed. All planktic foraminifers were identified to the species level. This report gives information on the raw counts and foraminifera flux (tests m−2 day−1) through May 2014. Flux was calculated based on the total number of foraminifera for each sub-sample, the fraction of the total sample used, the duration (days) the sediment trap was opened and collecting data for a given sample, and the aperture area of the sediment trap (0.5 meter-squared [m2]). The sediment trap mooring is currently deployed, and foraminifera data will be updated as new samples are processed. [More]
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