A scientist from Florida State University and one from the University of Hawaii will participate in the final two cruises of the CLIVAR Repeat Hydrography program to sample critical regions of the oceans of particular oceanographic significance and have not been previously sampled during this program. The first section will be S4P in 2011 which will sample a large normally inaccessible High Nutrient Low Chlorophyll (HNLC) region between 160°E and 110°W and involve at least three meridional sections into Antarctic coastal waters as well sampling along a zonal transect at roughly 67°S. The second section is the reoccupation of A16S between ~3°S and 55° S, currently scheduled for 2013 and will complete the Atlantic section. Water samples will be collected at approximately every other station occupied by the regular CLIVAR team, sampling 12 depths to 1000m. The samples will be analyzed on-board for dissolved iron and aluminum, nutrients, and salinity. Additional samples will be stored, acidified, and analyzed on shore for manganese, iron, cobalt, nickel, copper, zinc, cadmium, and lead using inductively coupled plasma mass spectrometry (ICP-MS). In collaboration with the U.S. GEOTRACES steering committee, seawater samples will be collected for shore-based determination of other trace elements and isotopes by other investigators. In addition, the researchers plan to continue the daily-integrated aerosol and event-based rainfall sampling, using existing CLIVAR aerosol and rainfall sampling equipment, as well as the high-volume aerosol sampling equipment and automated rainfall collectors recently purchased for use in the U.S. GEOTRACES program. This will allow us to provide subsamples to the U.S. and international "aerosol community". The aerosol samples will be analyzed for ultrapure water soluble, seawater soluble, and total trace elements using shore-based ICP-MS. Rain samples will be filtered (for samples greater than 200mL volume) and filtered and unfiltered subsamples will be stored frozen for shore-based major ion analyses and ICP-MS trace element analysis.
As regards broader impacts, availability of the trace metal dataset acquired as part of the CLIVAR Repeat Hydrography program will advance our knowledge of global biogeochemical cycles and will improve coupled biogeochemical models. Results from the study would be included into class lectures. One postdoc and one graduate student from Florida State University and two postdoc from the University of Hawaii will be supported and trained as part of this project.
