Seasonal flux and assemblage composition of planktic foraminifera from the northern Gulf of Mexico, 2008-2012

The U.S. Geological Survey anchored a sediment trap in the northern Gulf of Mexico beginning in 2008 to collect seasonal time-series data on the flux and assemblage composition of live planktic foraminifers. This report provides an update of the previous time-series data to include results from 2012. Ten species, or varieties, constituted ~92 percent of the 2012 assemblage: Globigerinoides ruber (pink and white varieties), Globigerinoides sacculifer, Globigerina calida, Globigerinella aequilateralis, Globorotalia menardii group [The Gt. menardii group includes Gt. menardii, Gt. tumida, and Gt. ungulata], Orbulina universa, Globorotalia truncatulinoides, Pulleniatina spp., and Neogloboquadrina dutertrei. The mean daily flux was 158 tests per square meter per day (m^–2 day^–1), with maximum fluxes of >450tests m^–2 day^–1 during the beginning of July and mid–August and minimum fluxes of <10 tests m^–2 day^–1 during the beginning of February and mid–July. Globorotalia truncatulinoides showed a clear preference for the winter, consistent with data from 2008 to 2011. Globigerinoides ruber (white) flux data for 2012 (average 23 tests m^–2 day^–1) were consistent with data from 2011 (average 30 tests m^–2 day^–1) and 2010 (average 29 tests m^–2 day^–1) and showed a steady threefold increase since 2009 (average 11 tests m^–2 day^–1) and a tenfold increase from the 2008 flux (3 tests m^–2 day^–1).