Table of Contents

• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

Synechococcus is one of the most abundant phytoplankton on earth and contributes significantly to marine primary production, thus an understanding of the distribution and diversity of this genus is important.  This quantitative PCR enumeration of nine marine Synechococcus clades found in multiple oceanic regimes is the most comprehensive study to date.  This work builds on the research of Zwirglmaier et al (2007 and 2008) and Tai and Palenik (2010), confirming patterns seen previously and extending observations into new areas, but it also provides new information on previously unstudied clades, the environmental niches of different clades, and defining the dominant oligotrophic clade.

Samples were collected on open ocean research cruises and coastal research cruises in locations throughout the Pacific and Atlantic oceans: The tropical North Atlantic (R/V Seward Johnson, SJ0609, in June 2006), the tropical South Atlantic and Benguela Upwelling system (CoFeMUG, R/V Knorr, KN192-05 Nov 2007), a transect through the North and South Pacific  (R/V Kilo Moana, KM0701 Feb 2007), the San Pedro Channel off Southern California (R/V Seawatch). The SPOT0509 cruise on R/V Seawatch was a single day cruise in May 2009 to the San Pedro Ocean Time Series station (33.55, -118.4).

Pacific: Transect from Hawaii to Brisbane, Australia
North Atlantic:  From Cape Verde to Barbados
South Atlantic: Brazil to Namibia
North Pacific from Hawaii to Bering Sea
Costa Rica Upwelling dome

Samples for all cruises, except the tropical North Atlantic and the South Pacific (from New Caledonia to Australia), were collected by taking a 100 ml sample from a Niskin bottle on the CTD rosette, filtered through a 0.4 um polycarbonate filter, and frozen at -20 °C until DNA extraction. In the North Atlantic and South Pacific, larger volumes (1-2 L with the volume always determined) were filtered onto 0.2 um polyethersulfone filters and frozen in liquid nitrogen.

BCO-DMO calculated lon from the lon_360 column provided by the PI. Parameter names were changed to conform to BCO-DMO convention.

The unicellular cyanobacterium Synechococcus is one of the most abundant primary producers in the marine environment. It is also extremely widespread; Synechococcus has been found in open ocean, coastal and even polar environments. Unlike its close relative, Prochlorococcus, Synechococcus has the ability to use NO3 and has been shown to respond in the field to NO3 inputs, suggesting that this organism may play a key role in global carbon cycling and especially new production. To date, 16 potential clades have been identified, and it is thought that this high diversity allows for the radiation of Synechococcus into many different environmental conditions. However, despite the ubiquity and abundance of Synechococcus, there are few studies characterizing the physiology and niche adaptations of each clade. Iron (Fe) shows great potential as a defining factor for niche adaptations, as its concentration varies over the geographic range of Synechococcus, as well as annually at specific locations, and has been shown to limit primary production in both open ocean and coastal settings. In addition, culture work indicates that Synechococcus strains have different abilities to grow on low concentrations of Fe. A comparison of the available genomes of marine Synechococcus shows great diversity in the presence or absence of known genes related to Fe stress, suggesting that Fe could have played a key role in the diversification and niche adaptation of Synechococcus. This project will study the effects of Fe on growth and carbon fixation in 11 different clades of Synechococcus (using at least 2 strains from each clade whenever possible) and the role of Fe limitation in determining the distribution of Synechococcus clades on temporal and spatial scales. This project will produce a comprehensive and systematic data set on the impact of Fe-specific niche differentiation in Synechococcus, offer new insight into the factors that control clade distribution, and provide understanding of the biogeochemical consequences of Synechococcus diversity.