Seasonal flux and assemblage composition of planktic foraminifera from the northern Gulf of Mexico, 2008–14

The U.S. Geological Survey anchored a sediment trap in the northern Gulf of Mexico in January 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 continuous results from January 2013 through May 2014. Ten taxa constituted ~95 percent of both the 2013 and 2014 assemblages: 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. In 2013, the mean daily flux was 177 tests per square meter per day (m⁻² day⁻¹), with maximum fluxes of >1,200 tests m⁻² day⁻¹ during the middle of February and minimum fluxes of <13 tests m⁻² day⁻¹ during the beginning of November. In 2014, the mean daily flux was 189 tests m⁻² day⁻¹, with maximum fluxes of >900 tests m⁻² day⁻¹ at the end of January and minimum fluxes of <30 tests m⁻² day⁻¹ at the beginning of January. Globorotalia truncatulinoides showed a clear preference for the winter, consistent with data from 2008 to 2012. 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). The flux data from 2013 (average 15 tests m⁻² day⁻¹) and 2014 (average 8 tests m⁻² day⁻¹) showed decline from the previous 3 years.