About

Dr. Adina Paytan is a Professor in the Earth and Planetary Sciences department at the University of California, Santa Cruz, with affiliations in the Institute of Marine Sciences and Ocean Sciences. Her research interests encompass biogeochemistry, chemical oceanography, paleoceanography, paleoclimatology, and environmental chemistry. Dr. Paytan's work focuses on understanding the chemical processes and historical changes in marine environments, contributing to knowledge about oceanic and atmospheric interactions over time. She leads a research lab that includes graduate students, postdoctoral researchers, and undergraduate students, fostering a collaborative environment for advancing studies in marine and earth sciences.

Research topics

• Oceanography
• Environmental chemistry
• Geology
• Environmental science
• Chemistry
• Earth science
• Ecology
• Geochemistry
• Materials science
• Political Science
• Mineralogy
• Environmental planning
• Business
• Environmental resource management
• Paleontology
• Biology
• Engineering
• Marketing
• Public relations
• Geography

Selected publications

• Thank You to Our 2025 Peer Reviewers

  GeoHealth · 2026-04-01

  articleOpen access

  Key Points The editors thank the 2025 peer reviewers

  PublisherDOI

• Inundation depth modulates wetland soil organic carbon stability by altering microbial biomass and mineral protection

  Geoderma · 2026-04-08

  articleOpen access
  PublisherDOI

• Modelling the Effects of Wetland Restoration on Coastal Hydrology: A Case Study of Elkhorn Slough Watershed, California

  Hydrological Processes · 2025-11-27

  articleOpen accessSenior author

  ABSTRACT Coastal wetlands, some of the most productive ecosystems on Earth, provide critical ecosystem services, including support of biodiversity, carbon sequestration and flood protection. In recent decades, these ecosystems have experienced extensive coastal wetland loss. Coastal wetland restoration provides a beacon of hope, offering a chance to reclaim these important habitats. However, even with billions of dollars invested worldwide in restoring coastal wetlands, we still lack comprehensive knowledge about the effectiveness of these restoration efforts in recovering wetland ecosystem functions and how future climate change may affect these efforts. The ability to evaluate how these ecosystems will function in the future is vital for examining current investments and developing future protection and management plans. We selected Elkhorn Slough, a tidal estuary, in California, to investigate the impact of wetland restoration and sea level rise (SLR) on coastal hydrology using the process‐based coastal hydrologic model, Advanced Terrestrial Simulator (ATS), informed by site‐specific data. We designed a novel modelling workflow for incorporating wetland restoration features into land cover and soil properties for the model parameterization. The validation results demonstrate a strong agreement between modelled and observed data. We studied the characteristics of coastal watershed hydrology, then focused on the surface water dynamics at two wetland sites within Elkhorn Slough, a reference site and a restored site. Our simulation results indicate that the restored site successfully maintains surface elevation, resulting in reduced surface inundation. We also examined the impact of wetland restoration under expected SLR over the next few decades. The low‐lying Yampah Marsh, the reference site, is likely to be inundated due to future SLR when highest tides arrive, while a higher percentage of Hester Marsh, the restored site, would retain marsh vegetation in coming decades, regardless of tidal conditions. Our study provides important information for examining the outcome of restoration practices that include surface elevation in tidal wetlands under climate changes.

  PublisherOA PDFDOI

• Phosphorus-to-calcium ratios in benthic foraminiferal shells as a proxy for coastal seawater phosphate concentrations

  Earth and Planetary Science Letters · 2025-01-13 · 2 citations

  article
  PublisherDOI

• AERO-MAP: a data compilation and modeling approach to understand spatial variability in fine- and coarse-mode aerosol composition

  Atmospheric chemistry and physics · 2025-05-06 · 6 citations

  articleOpen access

  Abstract. Aerosol particles are an important part of the Earth climate system, and their concentrations are spatially and temporally heterogeneous, as well as being variable in size and composition. Particles can interact with incoming solar radiation and outgoing longwave radiation, change cloud properties, affect photochemistry, impact surface air quality, change the albedo of snow and ice, and modulate carbon dioxide uptake by the land and ocean. High particulate matter concentrations at the surface represent an important public health hazard. There are substantial data sets describing aerosol particles in the literature or in public health databases, but they have not been compiled for easy use by the climate and air quality modeling community. Here, we present a new compilation of PM2.5 and PM10 surface observations, including measurements of aerosol composition, focusing on the spatial variability across different observational stations. Climate modelers are constantly looking for multiple independent lines of evidence to verify their models, and in situ surface concentration measurements, taken at the level of human settlement, present a valuable source of information about aerosols and their human impacts complementarily to the column averages or integrals often retrieved from satellites. We demonstrate a method for comparing the data sets to outputs from global climate models that are the basis for projections of future climate and large-scale aerosol transport patterns that influence local air quality. Annual trends and seasonal cycles are discussed briefly and are included in the compilation. Overall, most of the planet or even the land fraction does not have sufficient observations of surface concentrations – and, especially, particle composition – to characterize and understand the current distribution of particles. Climate models without ammonium nitrate aerosols omit ∼ 10 % of the globally averaged surface concentration of aerosol particles in both PM2.5 and PM10 size fractions, with up to 50 % of the surface concentrations not being included in some regions. In these regions, climate model aerosol forcing projections are likely to be incorrect as they do not include important trends in short-lived climate forcers.

  PublisherOA PDFDOI

• Vegetation Types Shift Physiological and Phenological Controls on Carbon Sink Strength in a Coastal Zone

  Global Change Biology · 2025-01-01 · 10 citations

  articleOpen access

  ABSTRACT The carbon sink function performed by the different vegetation types along the environmental gradient in coastal zones plays a vital role in mitigating climate change. However, inadequate understanding of its spatiotemporal variations across different vegetation types and associated regulatory mechanisms hampers determining its potential shifts in a changing climate. Here, we present long‐term (2011–2022) eddy covariance measurements of the net ecosystem exchange (NEE) of CO 2 at three sites with different vegetation types (tidal wetland, nontidal wetland, and cropland) in a coastal zone to examine the role of vegetation type on annual carbon sink strength. We found that the three study sites are stable carbon sinks and are influenced by their distinct physiological and phenological factors. The annual NEE of the tidal wetland, nontidal wetland, and cropland were determined predominantly by the seasonal peaks of net CO 2 uptake, release, and duration of CO 2 uptake period. Furthermore, the changes in annual NEE were sensitive to climatic variables, as spring mean air temperature reduced the carbon sink strength in the tidal wetland, maximum daily precipitation in summer reduced it in the nontidal wetland, and summer mean global radiation elicited the same effect in the cropland. Finally, a worldwide database of the three vegetation types was compiled, using which we further validated the global consistency of the biological controls. Overall, these results emphasize the importance of considering the underlying mechanisms by which vegetation types influence NEE for the accurate forecasting of carbon sink dynamics across different coastal vegetation types under climate change.

  PublisherOA PDFDOI

• Carbon Speciation and Concentration in California Salt Marsh Surface Waters Under Varied Land Use History and Management Regimes

  2025-01-01

  article
  PublisherDOI

• Viability of Prokaryotes in Nascent Aerosolized Sea Spray Across the Eastern Mediterranean Sea

  Journal of Geophysical Research Atmospheres · 2025-06-05

  article

  Abstract This study investigates the spatial distribution of viable prokaryotes and virus‐like particles (VLP) in nascent sea spray aerosols (SSA) across the Eastern Mediterranean Sea, including through mesoscale eddies, and two coastal oligotrophic sites. The percentage of viable prokaryotic cells ranged from 5% to 33% throughout the cruise transect. We observed positive coupling between the abundance of viable prokaryotes (∼1.9 × 10 2 to 4.4 × 10 4 cells m −3 ) and surface water chlorophyll‐ a levels and a negative relationship with temperature, reaching statistically significant maximal values in the relatively colder and algal‐richer stations by a factor of 1.3. VLP in SSA ranged from ∼9.5 × 10 4 to 1.2 × 10 6 m −3 , and were more enriched over oligotrophic warm waters. Comparative analyses of viability in the SSA and surface water showed a statistically significant decrease in prokaryote viability upon aerosolization from 35% to 29%, although their carbon uptake rate remained similar (121–145 fg C viable cell −1 d −1 ). These results provide new insights into prokaryote viability in nascent marine aerosols, emphasizing the need for further research on long‐term survival and ecological roles of aerosolized microbes.

  PublisherDOI

• Effects of climate change on river and groundwater nutrient inputs to the coastal ocean

  Communications Earth & Environment · 2025-09-24 · 13 citations

  articleOpen accessSenior author

  Rivers and groundwater are major sources of nutrients to the global coastal ocean. Climate change is expected to impact nutrient fluxes from river basins and coastal aquifers through alterations to both hydrological and nutrient cycling processes. In this Review, we identify and summarize how climate change impacts, such as changes in precipitation, increased cryosphere melt, and sea level rise, will affect water discharge and nutrient concentrations in rivers and coastal groundwater, which ultimately control nutrient inputs to the coastal ocean. We also document key limitations in the current understanding of climate-related changes to nutrient fluxes, especially in coastal groundwater basins. The impacts of climate change will interact with local human impacts, highlighting the need for studies spanning local to global scales to better understand and improve predictions of future nutrient fluxes from these hydrological pathways. Nutrient fluxes from rivers and groundwater flowing into the ocean are impacted by climate change impacts such as precipitation changes, cryosphere melt, and sea level rise.

  PublisherOA PDFDOI

• Controls on barite precipitation and preservation in Mediterranean sediments: from sapropel deposition to modern sedimentation

  2025-03-15

  preprintOpen accessCorresponding

  Mediterranean sediments have registered some of the most exceptional Ba records in marine basins. Although Organic Rich Layers (ORLs) are less well studied, both sapropels and ORLs are characterized by marked increases in Ba content in response to productivity oscillations, as demonstrated by numerous data sets and sediment records. During sapropel deposition, barite was abundantly produced in the water column due to increased productivity and associated microbial processes involved in organic matter degradation. In this scenario, bacterial activity and extracellular polymeric substances (EPS) have been shown to be the main control of barite precipitation in the water column, which is further supported by experimental work and observations from microenvironments of intense organic matter mineralization in the ocean water column. Once accumulated in marine sediments, barite tends to be well preserved in both eastern and western Mediterranean basins, where the availability of sulphate in pore waters prevented dissolution. Thus, differences in barite abundance in sapropels compared to ORLs support differences in productivity rates, and also differences in primary producers and microbial processes. Indeed, differences in productivity types between modern eastern and western basins also support that such differences over time may have led to spatial differences in barite formation. The general decline in productivity, and hence microbial activity, across the Mediterranean basins during the Holocene is indicated by the remarkably low Ba content in recent sediments. Dissolution of barite through the water column is also important in modern environments and is still poorly understood in the past. Overall, a better understanding of the microbial processes involved in barite production and the factors controlling its preservation is required to further constrain the information captured by Ba proxies.

  PublisherDOI

Recent grants

• U.S. Mexico Cooperative Research: Methane Fluxes and Cycling in Mangroves Ecosystems

  NSF · $11k · 2007–2008

• Resolving seawater stable (88Sr/86Sr) strontium isotope variations and their implications for the global strontium cycle

  NSF · $335k · 2013–2018

• Collaborative Research: Calibration, Validation, and Application of Barium Isotopes in Marine Barite as a Tracer of the Marine Carbon Cycle

  NSF · $93k · 2018–2020

• Atmospheric Deposition Impacts on Marine Ecosystems

  NSF · $515k · 2009–2015

• Ocean Acidification Category 2: Calcification in low saturation seawater: What can we learn from organisms in the proximity of low pH, undersaturated submarine springs?

  NSF · $262k · 2010–2015

Frequent coauthors

• Elizabeth M. Griffith

  The Ohio State University

  59 shared

• Carol Kendall

  Analytical Services

  57 shared

• M. B. Young

  56 shared

• Karen McLaughlin

  Southern California Coastal Water Research Project

  55 shared

• Katherine R. M. Mackey

  University of California, Irvine

  52 shared

• J. H. Street

  University of California, Santa Cruz

  43 shared

• Karen L. Knee

  American University

  39 shared

• Ellen Thomas

  Planetary Science Institute

  39 shared

Labs

• Paytan LabPI

Awards & honors

• Aliya Receives ARCS Fellowship (2026)
• Adina Elected to National Academy of Sciences (2026)
• Aliya Awarded Keeley Coastal Scholarship (2026)
• Leah Receives Myers Trust Funding (2026)
• Leah Receives GCA Award in Coastal Wetlands Studies (2026)