About

Professor Jefferson Moore is engaged in the development and application of marine ecosystem models on a global scale, specifically focusing on the mixed layer of the ocean. His work involves creating intermediate complexity models that simulate marine ecosystems and biogeochemical cycles, including iron cycling and nutrient limitation patterns in surface ocean waters. These models are designed to operate on a global domain and incorporate various environmental data inputs such as atmospheric iron deposition, sea ice cover, mixed layer depth, and sea surface temperature. Professor Moore's research integrates numerical methods and computational tools, including Fortran 77 and IDL routines, to run and analyze ecosystem models, enabling detailed studies of marine biogeochemical processes and their spatial and temporal variability. His contributions include the development of model code, input data sets, and visualization routines that support the understanding of nutrient dynamics and primary production in the world's oceans.

Research topics

• Geology
• Environmental science
• Oceanography
• Chemistry
• Ecology
• Computer Science
• Atmospheric sciences
• Earth science
• Climatology
• Physics
• Astrobiology
• Paleontology
• Biology
• Environmental chemistry
• Mathematics
• Meteorology

Selected publications

• Planetary Diagnosis of Phytoplankton Iron Stress

  2026-04-14

  article

  Iron limits phytoplankton growth across vast ocean areas, particularly in high-nutrient, low-chlorophyll regions. Yet, the global dynamics of iron stress remain poorly understood. Here, we integrate satellite-derived chlorophyll fluorescence observations, diverse field measurements, and a biogeochemical model to evaluate global phytoplankton iron stress over the past two decades. Satellite, field, and model observations show strong agreement and indicate vast ocean regions experiencing iron stress, including areas beyond traditional high-nutrient, low-chlorophyll regions. We observe climate-driven trends in iron stress associated with rising surface temperatures, with stress intensifying in mesotrophic and easing in oligotrophic waters. These contrasting trends are linked to shifts in co-limiting resource availability. Consequently, iron stress varies out of phase between the core upwelling zone and the broader equatorial Pacific during El Niño/Southern Oscillation cycles. Our findings suggest that future climate change will have opposing effects on iron limitation in nutrient-rich versus nutrient-poor marine biomes.

  PublisherDOI

• Simulating Marine Ecosystem Dynamics and Biogeochemical Cycling With Multiple Plankton Functional Types

  Journal of Advances in Modeling Earth Systems · 2025-07-01 · 3 citations

  articleOpen access

  Abstract Current representations of marine ecosystems in Earth System Models are greatly simplified, neglecting key interactions between dynamic food webs, biogeochemistry, and climate change. We use the Marine Biogeochemistry Library code base within the Community Earth System Model 2.2.2 to create an expanded ecosystem model with eight phytoplankton groups and four zooplankton size classes (MARBL‐8P4Z). Incorporating more specific plankton types and size classes has the potential to capture a wider range of possible behaviors of the ecosystem, its complex interactions with biogeochemistry, and its feedback to climate change. It also permits stronger observational constraints, including in situ group‐specific biomass and various observational estimates of plankton community composition. MARBL‐8P4Z broadly captures observed global‐scale patterns in biomass and community composition for both phytoplankton and zooplankton, with a good performance in simulating broad biogeochemistry fields. The model shows comparable spatial patterns and magnitudes to the observed picophytoplankton biomass ( Prochlorococcus, Synechococcus, picoeukaryotes), and captures the seasonal cycle of mesozooplankton biomass. Picophytoplankton groups and microzooplankton dominate biomass and production in oligotrophic, subtropical regions, while nano‐phytoplankton, diatoms and the larger zooplankton groups prevail at higher latitudes and within upwelling zones. The model simulates reasonable energy transfer efficiency through the food web, with tight linkages between the phytoplankton community composition, zooplankton grazing, and carbon export, with the potential to link to fisheries models. Thus, MARBL‐8P4Z has the potential to account for key climate‐driven ecological shifts in the plankton that will modify ocean biogeochemistry in the future.

  PublisherOA PDFDOI

• Addition of Macromolecular Marine DOM Cycling to the Marine Biogeochemistry Library (MARBL)

  Journal of Advances in Modeling Earth Systems · 2025-11-01

  articleOpen accessSenior author

  Abstract The differential cycling of marine macromolecules, such as dissolved carbohydrates, proteins, and lipids play a fundamental role in marine microbial metabolisms, ultimately regulating the ocean's capacity to sequester carbon downwards via the biological pump or move carbon up the food chain, supporting marine food webs. To date, their representation in global scale models of marine biogeochemistry and ecosystems is lacking. Here we add explicit representation of marine macromolecular cycling for dissolved polysaccharides, lipids, amino polysaccharides, and proteins, within the dissolved organic matter pools of the Marine Biogeochemistry Library (MARBL) ecosystem model, implemented within the ocean circulation model of the Community Earth System Model. The resulting dissolved macromolecule distributions identify polysaccharide and amino polysaccharide accumulation within the upper ocean of the subtropics owing to longer lifetimes than dissolved lipids and proteins which are diagnosed with shorter lifetimes and accumulate in more biologically productive regions. Representation of marine macromolecules is found to better match observed constraints of dissolved organic carbon to nitrogen stoichiometry patterns with depth than its MARBL predecessor which considers only bulk pools. This implementation of macromolecular cycling within the marine dissolved organic matter pool represents an important next step in better characterizing the complexity of natural organic matter within the marine ecosystem.

  PublisherOA PDFDOI

• Development of the E3SM Marine Biogeochemistry for Studying Biogeochemistry-Climate Feedbacks

  2025-12-20

  reportOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Addition of macromolecular marine DOM cycling to the Marine Biogeochemistry Library (MARBL)

  2025-06-23

  preprintOpen accessSenior author

  The differential cycling of marine macromolecules, such as dissolved carbohydrates, proteins, and lipids play a fundamental role in marine microbial metabolisms, ultimately regulating the ocean’s capacity to sequester carbon downwards via the biological pump or move carbon up the food chain, supporting marine food webs. To date, their representation is global scale models of marine biogeochemistry and ecosystems is lacking. Here we add explicit representation of marine macromolecular cycling for dissolved polysaccharides, lipids, amino polysaccharides, and proteins, within the dissolved organic matter pools of the Marine Biogeochemistry Library (MARBL) ecosystem model, implemented within the ocean circulation model of the Community Earth System Model. The resulting dissolved macromolecule distributions identifies polysaccharide and amino polysaccharide accumulation within the upper ocean of the subtropics owing to longer lifetimes than dissolved lipids and proteins which are diagnosed with shorter lifetimes and accumulate in more biologically productive regions. Representation of marine macromolecules is found to better match observed constraints of dissolved organic carbon to nitrogen stoichiometry patterns with depth than its MARBL predecessor which considers only bulk pools. This implementation of macromolecular cycling within the marine dissolved organic matter pool represents an important next step in better characterizing the complexity of natural organic matter within the marine ecosystem.

  PublisherOA PDFDOI

• Phytoplankton variable stoichiometry modifies key biogeochemical fluxes and the functioning of the ocean biological pump

  2025-05-27 · 1 citations

  preprintOpen access

  Ocean biota absorb carbon at the surface and export some to the ocean interior via the biological pump, affecting surface carbon, air-sea CO₂ exchange, and climate. Marine phytoplankton growth is often limited by nutrients (nitrogen, phosphorus, iron, silicon). The efficiency of carbon export is therefore constrained by nutrient availability and the nutrient/carbon ratios in the biota (stoichiometry). Field observations suggest widespread variability in phytoplankton stoichiometry (C/N/P/Fe/Si). Incorporating variable stoichiometry in marine biogeochemical models alters the magnitude and spatial patterns of carbon export by the biological pump and key nitrogen cycle fluxes, while fixed-stoichiometry models underestimate ocean carbon uptake and overestimate atmospheric CO₂. Thus, Earth System Models need to include dynamic plankton stoichiometry to enable more accurate projections of the carbon cycle and climate.

  PublisherOA PDFDOI

• Observed declines in upper ocean phosphate-to-nitrate availability

  Proceedings of the National Academy of Sciences · 2025-02-04 · 20 citations

  articleOpen access

  Climate warming is increasing ocean stratification, which in turn should decrease the nutrient flux to the upper ocean. This may slow marine primary productivity, causing cascading effects throughout food webs. However, observing changes in upper ocean nutrients is challenging because surface concentrations are often below detection limits. We show that the nutricline depth, where nutrient concentrations reach well-detected levels, is tied to productivity and upper ocean nutrient availability. Next, we quantify nutricline depths from a global database of observed vertical nitrate and phosphate profiles to assess contemporary trends in global nutrient availability (1972-2022). We find strong evidence that the P-nutricline (phosphacline) is mostly deepening, especially throughout the southern hemisphere, but the N-nutricline (nitracline) remains mostly stable. Earth System Model (ESM) simulations support the hypothesis that reduced iron stress and increased nitrogen fixation buffer the nitracline, but not phosphacline, against increasing stratification. These contemporary trends are expected to continue in the coming decades, leading to increasing phosphorus but not nitrogen stress for marine phytoplankton, with important ramifications for ocean biogeochemistry and food web dynamics.

  PublisherOA PDFDOI

• Phytoplankton variable elemental composition modifies the marine biological pump and largely determines the global patterns of nutrient limitation

  2024-03-08

  preprintOpen access

  Phytoplankton acclimate to increased nutrient stress by decreasing their cellular quotas (nutrient:carbon ratios). Reducing cellular quotas reduces the export efficiency of the limiting nutrient, helping sustain biological productivity. Here we present a version of the Community Earth System Model with phytoplankton group specific, fully variable C:N:P:Fe:Si ratios constrained by field observations of particulate organic matter stoichiometry and individual cell spectroscopy. We compare the results of a steady-state fully fixed stoichiometry model to the fully variable model and find that using a fixed Redfield stoichiometry leads to a decrease of 1PgC/yr carbon export, increase of 18 ppm atmospheric CO2, decrease of 55 TgN/yr nitrogen fixation, and decrease of 27/yr TgN nitrogen fixation. We also investigate the impacts of variable nutrient acquisition on global patterns of nutrient limitation and find that the weaker ability of phytoplankton to acclimate to N stress by lowering their cellular quotas relative to other nutrients pushes marine ecosystems towards nitrogen limitation. Only when the nutrient supply ratios are highly skewed, exceeding the ability of the phytoplankton to acclimate, do other nutrients become growth-limiting, as with iron in the High Nitrate, Low Chlorophyll (HNLC) regions. We show that in the oligotrophic gyres, variable plankton stoichiometry, given sufficient time, pushes the marine ecosystems towards co-limitation, as non-limiting nutrients are more efficiently drawn down and exported (higher cellular quotas), relative to the growth-limiting nutrient (lower cellular quotas).

  PublisherDOI

• Phytoplankton variable stoichiometry modifies key biogeochemical fluxes and the functioning of the ocean biological pump

  Research Square · 2024-07-12

  preprintOpen access
  PublisherOA PDFDOI

• Observed declines in upper ocean phosphate-to-nitrate availability

  ChemRxiv · 2024-05-26 · 2 citations

  preprintOpen access

  Climate warming is increasing ocean stratification, which in turn should decrease the flux of nutrients to the upper ocean. This may slow marine primary productivity, causing cascading effects throughout food webs. However, observing changes in nutrient concentrations at the ocean surface is challenging because they are often below detection limits. The nutricline depth, where nutrient concentrations reach well-detected levels, is related with productivity and indicates upper ocean nutrient availability. Here, we quantified nutricline depths from a global database of observed vertical nitrate and phosphate profiles (1972 - 2022) to assess contemporary trends in global nutrient availability. We found strong evidence that the P-nutricline (phosphacline) is mostly deepening, especially throughout the southern hemisphere, but the N-nutricline (nitracline) remains mostly stable. Earth System Model simulations support the hypothesis that reduced iron stress and increased nitrogen fixation buffer the nitracline, but not phosphacline, against increasing stratification. These contemporary trends are expected to continue in the coming decades, leading to increasing phosphorus but not nitrogen stress for marine phytoplankton, with important ramifications for ocean biogeochemistry and food web dynamics.

  PublisherOA PDFDOI

Recent grants

• A Model-Data Synthesis Study of the Marine Iron Cycle

  NSF · $314k · 2009–2012

• Collaborative Research: The Pan-Arctic climate and ecosystem response to historical and projected changes in the seasonality of sea ice melt and growth

  NSF · $92k · 2009–2013

• Collaborative research: Combining models and observations to constrain the marine iron cycle

  NSF · $471k · 2017–2021

• Collaborative Research: ETBC--The Cycling of Nitrogen in an Earth System Model: Constraints and Implications for Climate Change

  NSF · $472k · 2010–2014

• Global Atmospheric Nutrient Deposition and Ocean Biogeochemistry

  NSF · $499k · 2005–2009

Frequent coauthors

• Keith Lindsay

  Climate and Global Dynamics Laboratory

  80 shared

• Scott C. Doney

  University of Virginia

  53 shared

• François Primeau

  41 shared

• N. M. Mahowald

  Cornell University

  40 shared

• Matthew C. Long

  NSF National Center for Atmospheric Research

  30 shared

• James T. Randerson

  University of California, Irvine

  28 shared

• Adam C. Martiny

  University of California, Irvine

  26 shared

• Kazuhiro Misumi

  22 shared

Education

• B.A.

  University of Texas at Austin

  1988

• M.S.

  University of Massachusetts Boston

  1994

• Ph.D.

  Oregon State University

  1999