A5086775765- Marine and coastal ecosystems
- Microbial Community Ecology and Physiology
- Marine Biology and Ecology Research
- Methane Hydrates and Related Phenomena
- Ocean Acidification Effects and Responses
- Isotope Analysis in Ecology
- Hydrocarbon exploration and reservoir analysis
- Geology and Paleoclimatology Research
- Atmospheric and Environmental Gas Dynamics
- Radioactive contamination and transfer
- Radioactive element chemistry and processing
- Wastewater Treatment and Nitrogen Removal
- Coral and Marine Ecosystems Studies
- Marine Bivalve and Aquaculture Studies
- Protist diversity and phylogeny
- Algal biology and biofuel production
- Marine and environmental studies
- Atmospheric chemistry and aerosols
- Water Quality and Resources Studies
- Geochemistry and Elemental Analysis
- Marine and fisheries research
- Microbial bioremediation and biosurfactants
- Air Quality Monitoring and Forecasting
- Cassava research and cyanide
- Genomics and Phylogenetic Studies
Woods Hole Oceanographic Institution
2016-2025
Massachusetts Institute of Technology
1982-2024
Florida State University
2024
University of South Florida
2024
Southern California University for Professional Studies
2024
University of Southern California
2024
Scripps Institution of Oceanography
2004-2024
Institute of Oceanography
2024
University of Montana
2024
Texas A&M University
2024
Using a ternary gradlent s}istem, over 50 carotenoids, chlorophylls and their denvatives were separated from marine phytoplankton.Only 2 palrs of carotenoid pigments (19'-butanoyloxyfucoxanthin siphonaxanthin, 19'-hexanoyloxyfucoxanthin 9'-cis-neoxanthln) 3 (chlorophylls c , c2 Mg 2.4 divinyl pheoporphyrin a5 monomethyl ester [Mg2,4D]) not resolved.Pigment chromatograms are presented for 12 uniaigal cultures 10 algal classes important in the environment: Alnphidinlum cal-terae Hulbert...
DIssolVeD oRgaNIc MatteR IN the oceaN a coNtRoVeRsy stIMulates New INsIghts abstR act.Containing as much carbon atmosphere, marine dissolved organic matter is one of Earth's major reservoirs.With invigoration scientific inquiries into global cycle, our ignorance its role in ocean biogeochemistry became untenable.Rapid mobilization relevant research two decades ago required community to overcome early false leads, but subsequent progress examining dynamics this material has been...
Marine dissolved organic matter (DOM) contains as much carbon the Earth's atmosphere, and represents a critical component of global cycle. To better define microbial processes activities associated with marine DOM cycling, we analyzed genomic transcriptional responses communities to high-molecular-weight (HMWDOM) addition. The cell density in unamended control remained constant, very few transcript categories exhibiting significant differences over time. In contrast, DOM-amended microcosm...
Dissolved organic matter (DOM) in the oceans is one of largest pools reduced carbon on Earth, comparable size to atmospheric CO 2 reservoir. A vast number compounds are present DOM, and they play important roles all major element cycles, contribute storage ocean, support marine ecosystems, facilitate interactions between organisms. At heart DOM cycle lie molecular-level relationships individual members ocean microbiome that produce consume them. In past, these connections have eluded clear...
Significance Iron limits marine production across one third of the surface ocean. The chemical form iron in these regions is unknown, but it well established that molecular speciation affects microbial competition for uptake. Here we show abundance and identity siderophores, strong iron-binding compounds secreted by microbes to enhance uptake, changes iron-replete iron-deficient South Pacific Ocean. In low-iron regions, amphiphilic siderophores are particularly abundant, suggesting a...
Nitrogen isotopic measurements in fossil chlorophyll from late Pleistocene organic-rich sediments (sapropels) the eastern Mediterranean Sea provide geochemical evidence for stratified, nutrient-depleted surface water and extensive nitrogen fixation. This is reconciled with previous indications of high productivity by invoking a model sapropel formation which increased river discharge facilitates development specialized phytoplankton population whose annual mass sinking provides organic flux...
The pigments of the recently isolated marine prochlorophyte Prochlorococcus marinus were characterized by modern chromatographic and spectroscopic analysis. major photosynthetic pigment is 8‐desethyl, 8‐vinyl chlorophyll a . Accessory are b , zeaxanthin, α ‐carotene, an unknown carotenoid, possibly Mg 3,8 divinyl‐pheoporphyrin 5 Chl not present in this organism. P. first wild‐type oxygenic phototroph that does have as its it only procaryote ∊ ‐cyclic carotenoids ( ‐carotene). demonstrates...
The chemical dynamics of marine dissolved organic nitrogen (DON), a reservoir featuring surface accumulations even in areas where limits productivity, have yet to be resolved. We exploited differences the acid lability amide bonds within high-molecular-weight (HMW) DON show that vertical profiles result part from presence two chemically distinct pools amide. Half HMWDON waters is present as N-acetyl amino polysaccharides. In contrast, nearly all deep-sea HMWDON, and therefore, most amides...
Marine dissolved organic carbon (DOC) is a large (660 Pg C) reactive reservoir that mediates the oceanic microbial food web and interacts with climate on both short long timescales. Carbon isotopic content provides information DOC source via δ(13)C age Δ(14)C. Bulk isotope measurements suggest microbially sourced two distinct components of differing radiocarbon age. However, such cannot determine internal dynamics fluxes. Here we analyze serial oxidation experiments to quantify diversity at...
Production of dissolved organic matter (DOM) by marine phytoplankton supplies the majority substrate consumed heterotrophic bacterioplankton in sea. This production and subsequent consumption converts a vast quantity carbon, nitrogen, phosphorus between inorganic forms, directly impacting global cycles these biologically important elements. Details regarding chemical composition DOM produced are sparse, while often assumed, it is not currently known if phylogenetically distinct groups...
Anthropogenically driven climate change will rapidly become Earth's dominant transformative influence in the coming decades. The oceanic biological pump—the complex suite of processes that results transfer particulate and dissolved organic carbon from surface to deep ocean—constitutes main mechanism for removing CO2 atmosphere sequestering at depth on submillennium time scales. Variations efficacy pump strength ocean sink, which is larger than all other bioactive reservoirs, regulate have...
The phosphorus redox cycle Phosphorus in the oceans cycles between +5 and +3 oxidation states. Most of oceans' is present as oxidized bioavailable phosphate (+5) compounds. Reduced organophosphorus compounds are also but at much lower concentrations. Through field measurements western tropical North Atlantic Ocean a series laboratory incubations, Van Mooy et al. measured fast reduction rates small appreciable amount phosphates by plankton communities, forming phosphites phosphonates (see...
In tropical and subtropical oceanic surface waters phosphate scarcity can limit microbial productivity. However, these environments also have bioavailable forms of phosphorus incorporated into dissolved organic matter (DOM) that microbes with the necessary transport hydrolysis metabolic pathways access to supplement their requirements. this study we evaluated how environment shapes abundance taxonomic distribution bacterial carbon-phosphorus (C-P) lyase pathway, an enzyme complex evolved...
Sunlight is the dominant control on phytoplankton biosynthetic activity, and darkness deprives them of their primary external energy source. Changes in biochemical composition communities over diel light cycles attendant consequences for carbon flux environments remain poorly elucidated. Here we use lipidomic data from North Pacific subtropical gyre to show that biosynthesis energy-rich triacylglycerols (TAGs) by eukaryotic nanophytoplankton during day subsequent consumption at night drives...
The distribution of dissolved iron (Fe), total organic Fe-binding ligands, and siderophores were measured between the surface 400 m at Station ALOHA, a long term ecological study site in North Pacific Subtropical Gyre. Dissolved Fe concentrations low throughout water column strong ligands exceeded all depths; varying from 0.9 nmol L-1 to 1.6 below 150 m. Although does not appear limit microbial production, we nevertheless found nearly depths, indicating some populations microbes responding...
Significance Phosphonates are a class of phosphorus metabolites characterized by highly stable C-P bond. accumulate to high concentrations in seawater, fuel large fraction marine methane production, and serve as source microbes inhabiting nutrient-limited regions the oligotrophic ocean. Here, we show that 15% all bacterioplankton surface ocean have genes phosphonate synthesis most belong abundant groups Prochlorococcus SAR11. Genomic chemical evidence suggests phosphonates incorporated into...
We used compound-specific natural-abundance radiocarbon analyses of neutral sugars to study carbon cycling high-molecular-weight (HMW) dissolved organic (DOC) at two sites in the North Pacific Ocean. Sugars released from HMW DOC by acid hydrolysis were purified high-pressure liquid chromatography and analyzed for content via accelerator mass spectrometry. The seven most abundant recovered have similar values, supporting hypothesis that these are incorporated into a common family...