Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Parameters
• Instruments
• Deployments
• Project Information
• Program Information
• Funding

This dataset includes links to GenBank accession of 18S rRNA gene clone library sequences with the closest sequence matches from the NCBI database. The samples are from the upper water column as well as from shallow drifting traps during regular BATS cruises from December 2008-April 2010.

Water column samples were collected at BATS during the 2009 and 2010 winter bloom periods from the upper 150 m in Niskin bottles attached to a sampling rosette. Particle interceptor traps (PITs) with both fixed (2% formalin final concentration, deployment time 72 hr) and unfixed (deployment time 24 hr) collection tubes were deployed at 150 m depth in close proximity to the station and during the same time period as the water column collection in order to collect sinking particles below the euphotic zone. Clone libraries were constructed from 2-L samples collected at two depths in the euphotic zone, one close to the surface (10 m) and one from either the bottom of the euphotic zone if the water column was well mixed (most stations sampled; around 120-130 m) or from the chlorophyll maximum if one was present (around 80 m; samples from March 24 and April 24, 2010). Libraries were also constructed from sinking particles collected in two tubes of the PITs from the trap array located at 150 m depth. Unfixed traps were selected unless the sample was unavailable or prior results using DGGE indicated that the fixed trap would be more suitable due to occurrence of fungi and metazoans in the unfixed traps. DNA was extracted from these samples and a region of the 18S ribosomal RNA gene was amplified by PCR using eukaryotic primers. Samples from selected dates and depths were cloned and sequenced and broad taxonomic groups were determined for each sequence using their closest similarity match from BLAST (Basic Local Alignment Search Tool, http://blast.ncbi.nlm.nih.gov/).

DNA was extracted from environmental samples, 18S rRNA amplified by PCR, cloned and sequenced. Sequences were assigned taxonomic groups using their closest match on NCBI BLAST.

BCO-DMO Processing:

- added conventional header with dataset name; PI name; version date
- renamed parameters to BCO-DMO standard
- sequences not served; see NCBI accession number links
- added columns for cruise_id; cruise_name; year; month; day; sample_type; depth
- added html links to accession numbers
- removed trailing blanks and unprintable characters

The overall objective of this proposal is to investigate linkages between the presence of different key groups of phytoplankton in the euphotic zone and their contribution to particle flux at the subtropical North Atlantic time-series station BATS (Bermuda Atlantic Time-series Study) by applying a range of traditional and novel molecular techniques.

The 'biological pump', the photosynthetically mediated transformation of dissolved inorganic carbon into particulate and dissolved organic carbon in surface ocean waters and its subsequent export to deep water, is a significant driver of the atmospheric carbon uptake by the oceans. But this "biologically pumped" production, inasmuch as it depends on the composition and activity of planktonic organisms, is susceptible to long-term climatic changes in surface ocean properties such as increased temperature and changes in nutrient supply, especially in subtropical gyres. The sub-tropical gyres and the transition zones at their boundaries play an important role in the global carbon cycle because of their vast size and generally high per area export production. As evidenced in recent studies, the biological mechanisms driving regional to basin scale variability in carbon export in these biomes is far from understood, thus limiting our ability to mechanistically explain the biological pump and to predict its possible responses in the face of environmental change. In an effort to improve this situation with an accurate assessment of the contribution of different plankton groups to overall fluxes, the investigators will test the following two specific hypotheses: 1. The long held notion that large cells and those with mineral tests are major contributors to downward particle flux needs to be re-evaluated. We hypothesize that pico and nanoplankton (also those without mineral tests) are generally important contributors to downward particle flux at BATS. Consequently, the diversity of taxonomic groups contributing to particle flux is greater than previously expected. 2. The relative contribution of taxonomic groups to downward particle flux is a function of physical forcing. We hypothesize that episodic events (e.g., winter storms and eddies) lead to a reduction in diversity of sedimenting phytoplankton (e.g., dominance by a single group such as diatoms) compared to periods marked by more stable conditions in the water column. The broader impacts include furthering knowledge of the diversity and biology of phytoplankton groups that have a significant impact on the carbon export in subtropical gyres, thereby advancing our understanding of regional to basin scale variability in the biogeochemistry of these biomes. The project provides new opportunities for undergraduate and graduate education, as well as offer research opportunities to local high school students and teachers as part of the "Ask-a-Biologist" initiative. The project also includes an international component through collaboration with a molecular ecology group in Barcelona, Spain.

The Ocean Carbon and Biogeochemistry (OCB) program focuses on the ocean's role as a component of the global Earth system, bringing together research in geochemistry, ocean physics, and ecology that inform on and advance our understanding of ocean biogeochemistry. The overall program goals are to promote, plan, and coordinate collaborative, multidisciplinary research opportunities within the U.S. research community and with international partners. Important OCB-related activities currently include: the Ocean Carbon and Climate Change (OCCC) and the North American Carbon Program (NACP); U.S. contributions to IMBER, SOLAS, CARBOOCEAN; and numerous U.S. single-investigator and medium-size research projects funded by U.S. federal agencies including NASA, NOAA, and NSF.

The scientific mission of OCB is to study the evolving role of the ocean in the global carbon cycle, in the face of environmental variability and change through studies of marine biogeochemical cycles and associated ecosystems.

The overarching OCB science themes include improved understanding and prediction of: 1) oceanic uptake and release of atmospheric CO2 and other greenhouse gases and 2) environmental sensitivities of biogeochemical cycles, marine ecosystems, and interactions between the two.

The OCB Research Priorities (updated January 2012) include: ocean acidification; terrestrial/coastal carbon fluxes and exchanges; climate sensitivities of and change in ecosystem structure and associated impacts on biogeochemical cycles; mesopelagic ecological and biogeochemical interactions; benthic-pelagic feedbacks on biogeochemical cycles; ocean carbon uptake and storage; and expanding low-oxygen conditions in the coastal and open oceans.