JPR Advance Access published September 12, 2015 Journal of Plankton Research plankt.oxfordjournals.org J. Plankton Res. (2015) 0(0): 1–14. doi:10.1093/plankt/fbv077 Costa Rica Dome: Flux and Zinc Experiments Net biogenic silica production and Downloaded from the contribution of diatoms to new production and organic matter export http://plankt.oxfordjournals.org/ in the Costa Rica Dome ecosystem JEFFREY W.KRAUSE1,2*, MICHAEL R. STUKEL3, ANDREW G. TAYLOR4, DARCYA. A. TANIGUCHI4,5, ALAIN DE VERNEIL4 AND MICHAEL R. LANDRY4 1 2 DAUPHIN ISLAND SEA LAB, 101 BIENVILLE BLVD, DAUPHIN ISLAND, AL 36528, USA, UNIVERSITY OF SOUTH ALABAMA, LIFE SCIENCES BUILDING ROOM 25, 3 4 MOBILE, AL 36688, USA, FLORIDA STATE UNIVERSITY, P.O. BOX 3064520, TALLAHASSEE, FL 32306-4520, USA, SCRIPPS INSTITUTION OF OCEANOGRAPHY, 5 by guest on September 13, 2015 9500 GILMAN DR., LA JOLLA, CA 92093-0227, USA AND MASSACHUSETTS INSTITUTE OF TECHNOLOGY, 77 MASSACHUSETTS AVENUE, BUILDING 54-1511A, CAMBRIDGE, MA 02142, USA *CORRESPONDING AUTHOR:
[email protected] Received April 17, 2015; accepted August 21, 2015 Corresponding editor: Pia Moisander We determined the net rate of biogenic silica (bSiO2) production and estimated the diatom contribution to new pro- duction and organic matter export in the Costa Rica Dome during summer 2010. The shallow thermocline signifi- cantly reduces bSiO2 dissolution rates below the mixed layer, leading to significant enhancement of bSiO2 relative to organic matter (silicate-pump condition). This may explain why deep export of bSiO2 in this region is elevated by an order of magnitude relative to comparable systems. Diatom carbon, relative to autotrophic carbon, was low (,3%); however, the contribution of diatoms to new production averaged 3 and 13% using independent approaches.