Jack DiTullio - Chief Scientist - University of Charleston
David Hutchins - University of Delaware
Walker Smith - Virginia Institute of Marine Science
Peter Sedwick - Bermuda Institue of Ocean Sciences (formerly BBSR)
Robert Dunbar - Stanford University
Philippe Tortell - U. British Columbia
Andrew Bowie - U. of Tasmania
Mak Saito - Woods Hole Oceanographic Institution
Funded by NSF Office of Polar Programs
Our main objective in this proposed research is to
investigate the relative importance and potential interactive effects of iron,
light and CO2 levels in structuring algal assemblages and growth rates in the Ross Sea.
We hypothesize that the interaction of these three variables largely determines
the bottom-up control on these two dominant Southern Ocean phytoplankton taxa.
Grazing and other loss processes will also be important variables in
determining the relative dominance of these two taxa; however, the study
proposed here will primarily focus on the bottom-up control mechanisms. It is
important to understand such environmentally-driven taxonomic shifts in primary
production, since they are expected to impact the fixation and export of carbon
and nutrients, and the production of DMS, thus potentially providing both
positive and negative feedbacks on climate.
Within the context of this proposal, we consider a range of ambient iron, light
and pCO2 levels that span those typically observed in the Ross Sea
during the growing season. That is, dissolved iron ranging from ~0.1 nM
(“low iron”) to >1 nM (“high iron”) (Fitzwater et al. 2000; Sedwick et al.
2000); mean irradiance (resulting from vertical mixing/self shading) ranging
from <10% Io (“low light”) to >40% (“high light”) (Arrigo et al., 1998,
1999), which may be adjusted based on our field observations (see section
6.3.3); and pCO2 ranging (Sweeney et al. 2001) from ~150 ppm (“low CO2”) to the
probable higher levels of pCO2 750 ppm as a conservative estimate that are
likely to be attained later this century due to anthropogenic perturbation of
the global carbon cycle (IPCC, 2001).
From the information currently available from both field observations and
experiments, we have formulated the following specific hypotheses regarding the
interactive role of iron, light and CO2 in regulating algal composition in the Ross Sea.
Principally, we propose that diatoms bloom in the southern Ross Sea only under
optimum conditions of high iron, light and pCO2; colonial Phaeocystis dominate
under conditions of high iron with either (or both) low light or low pCO2; and
solitary Phaeocystis are predominant under conditions of low iron with either
(or both) low light or low pCO2. Two cruises are planned to investigate
the interactions between the primary productivity of the Ross Sea
and pCO2, iron and other trace elements.
Jack DiTullio - CORSACS Chief Scientist , University of Charleston Ana Aguilar-Islas - Grad student, UCSC Thomas Baird Erin Bertrand - Grad student, WHOI Giulio Catalano Rob Dunbar - P.I., Stanford University Yuanyuan Feng - Grad student Jay Francella - Grad student Nathan Garcia Tyler Goepfert - Research Assistant, WHOI Clint Hare - Grad student Dave Hutchins, PI, University of Delaware Lindsey Kropuenske Peter Lee - Post-doc Yingyu Li Maeve Lohan - Senior Lecturer, U Plymouth, UK Matt Long - Ph.D. student, Stanford University Christopher Marsay - Research Associate, BIOS (formerly BBSR) Juliana Miller Angela Milne Dave Mucciarone - Lab Manager, Stanford University Aimee Neeley - Research Assistant Christopher Payne - Grad student Scott Polk Okori Puryear Quinn Roberts Julie Rose - Postdoc Mak Saito - PI, WHOI Pete Sedwick - PI, BIOS (formerly BBSR) Walker Smith - PI, Virginia Institute of Marine Science Sasha Tozzi - Grad student Scarlett Trimborn
Science Party 2005
Jack DiTullio - CORSACS Chief Scientist , University of Charleston Peter Lee, Post-doc David Jones, Research Associate Aimee Neeley, Research Assistant Jay Francella, Grad student Brian Taylor, Research Assistant Rob Dunbar, P.I., Stanford University Dave Mucciarone, Lab Manager, Stanford University Eduard Costa, Post-doctoral fellow, Stanford University Matt Long, Ph.D. student, Stanford University Christina Riesselman, Ph.D. student, Stanford University Dave Hutchins (PI), Clint Hare (grad student), Yuanyuan Feng (grad student), Sara Handy (grad student), Julie Rose (postdoc) Mak Saito (PI), Abigail Noble (Research Assistant), Tyler Goepfert (Research Assistant), Erin Bertrand (Research Assistant). Peter Sedwick (PI, BBSR) Chris Marsay (research associate, BBSR) Maeve Lohan (Senior Lecturer, U Plymouth, UK) Ana Aguilar-Islas (grad student, UCSC) Juliette Tria (grad student, U Tasmania) Walker Smith, PI Virginia Institute of Marine Science Jill Peloquin, Post-doc Sasha Tozzi (grad student) Carol Pollard (grad student) Jennifer Dreyer (grad student) Phillipe Tortel (PI) University of British Columbia Celine Gueguen (postdoc) Chris Payne (grad student)