Bigelow Laboratory leads a five-week, multi-institutional transect across the South Atlantic.
Beginning on January 11, 2011, a team of Bigelow scientists embarked on a research expedition aboard the R/V Melville, crossing 6,924 miles of the South Atlantic Ocean from Punta Arenas, Chile to Cape Town, South Africa. The researchers were investigating the effects of ocean acidification on the Southern Hemisphere’s largest recurring phytoplankton bloom, known as the Great Southern Coccolithophore Belt. It is likely that the massive extent of the Great Belt (it covers approximately 26% of the world's ocean) has a major role in global biogeochemistry and climate change feedbacks.
Senior Research Scientist (SRS) Dr. Barney Balch was the Chief Scientist for the National Science Foundation-sponsored expedition, joined by SRS Dr. Ben Twining, Research Associates Bruce Bowler, Dave Drapeau, and Sara Rauschenberg, and Research Technician Laura Lubelczyk. The 23-member team included scientists from the Bermuda Institute of Ocean Sciences, Woods Hole Oceanographic Institution, the University of Miami, and Colby College, as well as students from Western Washington University and Colby College. Also on board as an “Educator at Sea” was Bigelow Education Director Rebecca Fowler, who shared information about research activities, science, and life at sea through The Great Belt Research Cruise website, photo journal, and blog. Photo by R. Fowler.
Proposed cruise track.
Recent advances in satellite remote sensing enable estimation of suspended calcium carbonate (particulate inorganic carbon or “PIC”) from space. This radiative approach is operationally specific to marine coccolithophores (Haptophyceae) and sensitive enough to quantify PIC concentrations in oligotrophic gyres. Global images of suspended PIC taken over the seven years of the MODIS Aqua mission show a “Great Belt” of PIC near the sub-Antarctic front of the Southern Ocean that circles the globe. This feature occurs every year during austral summer and appears to be within the high-nutrient, low chlorophyll region of the Southern Ocean. The area of the Great Belt is ~88 million km2, 26% of the global ocean. Evidence from several cruises into the Great Belt region of the Atlantic, Indian and Pacific sectors has verified elevated concentrations of coccolithophores; previous work in the Atlantic sector verified high optical scattering from PIC. The few ship observations are entirely consistent with the satellite views. Here we propose the first systematic study of the coccolithophores of the Great Belt. We have seven science goals:
(a) identify the coccolithophore species within this belt; (b) measure the abundance of coccolithophores and associated PIC; (c) measure coccolithopore calcification rates; (d) elucidate factors that may limit coccolithophore latitudinal range (e.g. stratification, temperature, macronutrients, trace metals, grazing); (e) demonstrate whether the variability in PIC relates to shallow export flux; (f) define how variability in PIC production relates to the pCO2, total alkalinity and dissolved inorganic carbon budgets; and (g) examine the impact of short-term ocean acidification on coccolithophore growth and calcite dissolution. We propose three cruises to systematically sample the Great Belt along the 50oS parallel, during the austral summers of 2011, 2012 and 2013. Using a combination of underway surface sampling (primarily optical and hydrographic) and vertical station profiles (using CTD/rosette and large volume submersible pumps), we will address hypotheses related to the above goals. The cruise track will elucidate both zonal and meridional variability in the Great Belt. Controlled carboy incubation experiments will examine the impact of ocean acidification (at various future scenarios) on coccolithophore growth and dissolution. Dilution experiments will address grazing-related mortality and dissolution questions. Controlled metal-addition incubations will focus on potential iron, zinc and cobalt limitation of the coccolithophores or competition from diatoms related to silica availability. The proposed field observations and metal-addition experiments will go far to define the current status of the Great Belt in the context of global biogeochemistry. The proposed ocean acidification experiments are more forward looking in terms of the fate of the Southern Ocean coccolithophores in a future acidified ocean.
First U.S. Expedition of the International GEOTRACES Project (October-December, 2010)
Sara Rauschenberg, research associate in the Trace Metal Biogeochemistry Laboratory is currently on a 52-day expedition on the R/V Knorr to study the distributions of trace metals in the North Atlantic Ocean as part of the large international GEOTRACES project. Rauschenberg is joining 32 other trace metal chemists from the United States to collect particles and phytoplankton cells from throughout the full water column (down to 4500 m) along a transect running from Lisbon, Portugal to Woods Hole, Massachusetts. The ship will arrive on December 5, 2010, having sailed south to the upwelling region off of West Africa, past the Cape Verde islands, over the hydrothermally-active mid-Atlantic ridge, through the Sargasso Sea, and across the continental shelf of the eastern United States. Following the cruise, the metal (Fe, Mn, Co, Cu, Ni, Zn, Al, Cd) contents in the sampled cells will be determined using state-of-the-art mass spectrometry and synchrotron techniques. Other members of the expedition team are measuring the concentrations and chemical speciation of numerous additional elements in the water and particulate matter. The cruise is part of a three-year National Science Foundation grant to Senior Research Scientist Ben Twining. A number of countries, including the Netherlands and Great Britain, are conducting transect cruises in other parts of the Atlantic Ocean, and the results will be combined to advance understanding of the distribution and cycling of metals in the oceans.
The Costa Rica Dome Expedition (June-July, 2010)
2010 summer interns Ali Brandeis of Colby College and Bowdoin College senior Kelly Keebler are aboard the oceanographic ship R/V Melville with Senior Research Scientist Dr. Joaquim Goés off the coast of Costa Rica (in an area of the Pacific Ocean 500 to 800 miles west of Costa Rica in the eastern equatorial Pacific known as the Costa Rica Dome), as part of a month-long, National Science Foundation-sponsored research cruise studying grazing and iron controls of diatom blooms. Originally, the cruise was to take place in the Arabian Sea, but concerns about piracy required relocation to the Costa Rica Dome, which has a similar upwelling system as the Arabian Sea and where phytoplankton blooms are constrained by both iron limitation and microzooplankton grazing.
Led by Dr. Mike Landry of Scripps Institute of Oceanography, the major research focus of the project is to understand controls on phytoplankton growth and bloom formation in the Costa Rica Dome. Keebler and Brandeis will join other scientists on board in examining how nutrients, trace metals, solar light, and grazing by zooplankton interact to regulate phytoplankton populations in the water column. In particular, this study will examine why Synechococcus (a tiny unicellular cyanobacterium) dominates the upper mixed layer of the Costa Rica Dome, and why diatoms dominate in deeper waters. The team will investigate the importance of trace metals, zinc, iron, and the inorganic nutrient silicate in regulating the distribution of different phytoplankton population groups in the upper lighted layers of the Dome.
Funding from the National Science Foundation and the Maine Space Grants Consortium will also allow Keebler and Brandeis to conduct independent research projects to understand how nutrients and solar light levels combine to impact the photo-physiological properties, growth rates, and distribution patters of different phytoplankton groups of the Costa Rica Dome.
Above: Keebler (left) and Brandeis (right) with incubators on the deck of the R/V Melville. Both interns are posting personal blogs about their life and work on board the ship. Follow the cruise with them through Gnome on a Boat and Keebler in Costa Rica. Photo by Dr. Joaquim Goés.
The ANACONDAS Expedition: Studying the Amazon Continuum (May-June, 2010)
Bigelow scientists Drs. Joaquim Goés and Helga do Rosario Gomes are members of an international team of 47 multidisciplinary researchers currently on an oceanographic ship off the coast of South America to study climate change where the Amazon River flows into the Atlantic Ocean. The plume of the nearly 4,000-mile long Amazon River extends far out to sea; together the river and its plume are known as the Amazon Continuum. The Continuum and its associated carbon cycle extend hundreds of miles into the open ocean. Information about the dynamic processes within this ecosystem is vital to understanding regional and global human impacts on the tropical open ocean and potential feedbacks to climate change. Bigelow intern Courtney Beaulieu from Colby College in Waterville, Maine is also on board as one of 14 student researchers. She is posting updates about her research activities and life on board the R/V Knorr on her blog Plumes and Blooms. Team member and middle school science teacher Lollie Garay from Redd School in Houston, Texas is posting The Amazon Continuum, another an active blog from the ship. (Note: The views expressed in both blogs are the authors' own.)
(Image courtesy of NASA.)
Dr. Michael Sieracki, Director of the Laboratory’s J. J. MacIsaac Facility for Individual Particle Analysis, has completed a stint as Chief Scientist on board the 3-year Tara Oceans research expedition. Sieracki led science the team for several weeks, sailing from Malta to Dubrovnik to train researchers aboard the vessel in the use of at-sea flow cytometry and imaging technology, instruments first developed at Bigelow Laboratory.
Tara's imaging platform is called T.A.O.M.I. (Tara Oceans Marine biology Imaging platform) and is dedicated to marine biology and the observation of plankton (from a few micrometers to a centimeter in size). Flow analyses continuously measure the variations of the surface water and its plankton community.
Visit the Tara Oceans website to follow the expedition online, and listen to MPBN's interview with Dr. Sieracki aboard Tara, which aired on Maine Things Considered on November 13. (Photo courtesy of Tara Oceans.)
Arctic Summer Cloud Ocean Study (August, 2008)
(A month-long mission to the high Arctic Ocean aboard the Swedish icebreaker Oden to investigate the physical processes leading to cloud formation in this critically-important global region.) Listen to Maine Public Radio's interview with team leader Dr. Paty Matrai from above the Arctic Circle, and read the cruise blog from the expedition.
(Photo by Thorsten Mauritsen.)