Publications by authors named "J D Liefer"

Article Synopsis
  • The study examines how the ratios of carbon, nitrogen, and phosphorus (C:N:P) in ocean particulate matter differ from the standard Redfield Ratio, impacting global carbon storage as these particles sink into the deep ocean.
  • Researchers found distinct latitudinal patterns in C:N:P ratios along a transect in the North Pacific, linking these patterns to the composition of macromolecules like proteins, carbohydrates, and lipids in oceanic particles.
  • The findings suggest that changes in phytoplankton community structure and nutrient availability are key factors driving variations in these ratios, indicating that physiological acclimation to nutrient supply is likely responsible for the observed latitudinal trends.
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Phytoplankton Chl:C:N:P ratios are important from both an ecological and a biogeochemical perspective. We show that these elemental ratios can be represented by a phytoplankton physiological model of low complexity that includes major cellular macromolecular pools. In particular, our model resolves time-dependent intracellular pools of chlorophyll, proteins, nucleic acids, carbohydrates/lipids, and N and P storage.

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The elemental composition of marine microorganisms (their C:N:P ratio, or stoichiometry) is central to understanding the biotic and biogeochemical processes underlying key marine ecosystem functions. Phytoplankton C:N:P is species specific and flexible to changing environmental conditions. However, bulk or fixed phytoplankton stoichiometry is usually assumed in biogeochemical and ecological models because more realistic, environmentally responsive C:N:P ratios have yet to be defined for key functional groups.

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Extensive microdiversity within , the most abundant marine cyanobacterium, occurs at scales from a single droplet of seawater to ocean basins. To interpret the structuring role of variations in genetic potential, as well as metabolic and physiological acclimation, we developed a mechanistic constraint-based modeling framework that incorporates the full suite of genes, proteins, metabolic reactions, pigments, and biochemical compositions of 69 sequenced isolates spanning the pangenome. Optimizing each strain to the local, observed physical and chemical environment along an Atlantic Ocean transect, we predicted variations in strain-specific patterns of growth rate, metabolic configuration, and physiological state, defining subtle niche subspaces directly attributable to differences in their encoded metabolic potential.

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Ciguatera poisoning (CP) poses a significant threat to ecosystem services and fishery resources in coastal communities. The CP-causative ciguatoxins (CTXs) are produced by benthic dinoflagellates including and spp., and enter reef food webs via grazing on macroalgal substrates.

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