About

Aron Stubbins is a professor of marine and environmental sciences at Northeastern University, with a background rooted in Wales and a PhD in Marine Biogeochemistry from Newcastle University in England. His research focuses on the natural carbon cycle, how human activities alter it, and the role of plastics as a novel component of the carbon cycle and potential pollutants. He has contributed to understanding the abundance and impact of microplastics in the ocean, including their effect on the ocean's ability to sequester carbon and their chemical byproducts when broken down by sunlight. Stubbins has been involved in studies examining plastic pollution in deep-sea environments, coastal carbon outwelling, and the broader ecological and climate implications of plastics in marine systems. His work also explores the influence of environmental factors such as wildfire soot on ocean chemistry and the interactions between human activity and marine ecosystems.

Research topics

• Remote sensing
• Chromatography
• Chemistry
• Physics
• Biology
• Environmental chemistry
• Astrobiology
• Astronomy
• Environmental science
• Organic chemistry

Selected publications

• Organic pollution found oceanwide

  Nature Geoscience · 2026-04-01

  article1st authorCorresponding
  PublisherDOI

• Photooxidation promotes sinking of polyethylene microplastics during early-stage biofouling

  Marine Pollution Bulletin · 2026-04-10

  articleOpen access

  Microplastics (MPs) are ubiquitous in the ocean and even low density polymers such as polyethylene (PE) are found below the surface and in seafloor sediments. Predicting when and how buoyant MPs lose buoyancy remains challenging, particularly because photooxidation and biofouling can co-occur at the ocean surface. Here, we tested a two-step mechanism: photooxidation followed by early stage biofouling and quantified its effect on PE MP buoyancy and sinking under controlled laboratory conditions. MPs were prepared from post-consumer PE grocery bags and photo-oxidized for 82 days in a solar simulator. Pristine and photooxidized MPs were incubated for 15 days in coastal seawater containing natural microbial assemblages, either unamended or amended with the diatom Chaetoceros tenuissimus or the coccolithophore Emiliania huxleyi . Biofilms formed within five days on both PE MPs across all live treatments, showing minor differences in crystal violet based biofilm intensity through day 15. Most notably, all pristine PE MPs ( n = 27) remained positively buoyant, while 92% of the photo-oxidized PE MPs sank to the bottom of a 31 cm water column within 5 days. Prior to biofouling, photo-oxidized PE MPs exhibited negative buoyancy in the top sinking column without reaching the bottom. Our results suggest photooxidation can precondition PE MPs such that early stage biofouling triggers buoyancy loss on timescales of days rather than the weeks to months often reported for pristine MPs. Our results highlight the need to consider photooxidation in biofouling studies to better predict the fate of MPs in the ocean. • A two step mechanism, photooxidation followed by early biofouling, rapidly induced polyethylene microplastics sinking. • Photooxidized polyethylene microplastics showed transient partial descent even before biofouling. • 92% of photooxidized polyethylene microplastics sank within 5 days across live seawater treatments. • Pristine polyethylene microplastics remained buoyant through day 15 despite biofilm formation.

  PublisherDOI

• Evaluating drivers of environmental change in a lake sediment core: Insights from spectroscopic metrics of water-extractable organic matter and stable carbon isotopes

  Applied Geochemistry · 2026-03-09

  articleOpen access

  Freshwater lakes play a critical role in the global carbon cycle by storing and transforming organic matter (OM) from both terrestrial and aquatic sources. Small lakes in northern temperate regions, despite their limited surface area, disproportionately influence regional carbon budgets. Buried sediments integrate OM inputs over time and archive ecosystem responses to natural and anthropogenic disturbances. However, the direction and magnitude of recent environmental changes on sediment carbon (C) dynamics remain poorly understood. A 23-centimeter core was collected from a small temperate lake in northeastern USA to evaluate sediment OM content and composition over timescales relevant to historical land-use change, damming, and recovery from acid deposition. Patterns in OM burial and source contributions were revealed via elemental and isotopic analyses of bulk OM and UV–Vis spectrophotometry of water-extractable organic matter (WEOM). The optical metrics expanded observations of likely OM sources beyond the information gained from bulk carbon metrics (total carbon, δ 13 C). The aromaticity of WEOM increased downcore, which is consistent with a shift from increased terrestrial inputs during early logging and damming activity (pre ∼1920) to more microbial-derived OM in recent surficial sediments. Future applications of WEOM optical properties as complements to traditional geochemical metrics can enhance interpretations of lake ecosystem responses recorded in lake sediments to environmental perturbations in temperate lakes. • Highlights (85 character max per point including spaces) • Water-extractable organic matter from lake sediments reveals environmental history • WEOM optical metrics vary more across sediment depth than bulk geochemical metrics • WEOM metrics show promise for broader geochemical applications in lake sediments

  PublisherDOI

• <i>Legionella</i> and <i>Mycobacterium</i> populations exhibit geographic structuring across and within drinking water systems

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-01-14 · 1 citations

  articleOpen access

  Abstract Opportunistic pathogens (OPs) within the Legionella and Mycobacterium can persist and sometimes proliferate in drinking water systems and pose a risk to public health. Most prior research has focused on isolated system components of the drinking water treatment and distribution system and has rarely examined spatiotemporal dynamics across the entire source water, treatment process, and distribution system continuum. This study addresses this critical knowledge gap by quantitative profiling of microbial communities with full length 16S rRNA gene sequencing and flow cytometry, and associated water chemistry parameters, including disinfection byproducts (DBPs), across five full-scale utilities. These utilities reflect varying source water types, geographic locations, treatment regimes, and climate zones. Microbial communities, including Legionella and Mycobacterium populations, in distribution system were shaped by source water type and exhibited significant community divergence across utilities. Within the same genus, strain-level analyses revealed highly distinct Legionella and Mycobacterium sequence variants unique to each utility. Interestingly, a substantial proportion of Legionella and Mycobacterium amplicon sequence variants were both utility specific and often specific to locations within the distribution system, indicating strong geographic structuring both across and within drinking water systems. Understanding the mechanistic underpinnings of this geographic structuring is critical to develop robust strategies for managing and monitoring Legionella and Mycobacterium populations in drinking water systems.

  PublisherOA PDFDOI

• Towards an improved understanding of the magnitude and drivers of carbon and nitrogen storage and accumulation in urban saltmarshes: a case study from New England (USA)

  Urban Ecosystems · 2026-03-17

  articleOpen access

  Urban saltmarshes, although often heavily modified yet critical for nature-based climate and water quality management strategies, remain insufficiently integrated into coastal sustainability policy and practice. This study quantified soil organic carbon (SOC) and nitrogen (SN) stocks and accumulation in Belle Isle Marsh, Boston, USA, using 26 soil cores collected to 1 m depth across upland transitional marsh, high marsh, low marsh, and unvegetated marsh habitats. Mean (± SD) SOC and SN stocks in the upper meter were 332 ± 144 Mg C ha− 1 and 17 ± 4 Mg N ha− 1, respectively, values comparable to global temperate saltmarsh estimates. High marshes consistently held the highest stocks, while unvegetated and upland transitional marsh habitats exhibited lower and more variable stocks. Stocks and accumulation were strongly influenced by dry bulk density and sediment-size distribution, reflecting how sediment composition affects carbon and nitrogen storage. Using ¹³⁷Cs radionuclide dating, sediment accretion rates ranged from 0.29 to 0.79 cm− 2 yr− 1, and corresponding to carbon and nitrogen accumulation rates from 80 to 183 g C m− 2 yr− 1 and 2 to 15 g N m− 2 yr− 1, respectively. These findings demonstrate that urban saltmarshes can sustain carbon and nitrogen stocks and burial rates comparable to global ranges, even under sustained anthropogenic pressure. However, the same forces that shape these systems also threaten their long-term storage capacity, underscoring the urgency of conserving and restoring urban wetlands and fully integrating them into regional and global carbon and nutrient management frameworks.

  PublisherOA PDFDOI

• Interpretable Machine Learning Reveals Integrated Water Chemistry and Parameter-Specific Nonlinear Responses Shaping <i>Legionella</i> spp. and <i>Mycobacterium</i> spp. in Drinking Water

  medRxiv · 2026-04-27

  article

  Abstract Traditionally, studies have explored the impacts of individual water chemistry parameters on the persistence of Mycobacterium spp. and Legionella spp. in isolation with the underlying assumption that these associations are likely monotonic in nature. Yet chemical and microbiological changes are complex, and associations are likely highly combinatorial. In this study, we use interpretable machine learning models to disentangle the integrative and nonlinear associations between water chemistry and occurrence/abundance of Mycobacterium spp. and Legionella spp. Seasonal data from source water, point-of-entry and distribution systems of eight full-scale drinking water systems demonstrated that shifts in overall water chemistry were associated with the changes in microbial abundance during treatment and distribution. Machine learning models indicated moderate predictive ability of integrated water chemistry towards Legionella spp. abundance and towards the occurrence of both Legionella spp. and Mycobacterium spp., whereas predictive performance for Mycobacterium spp. abundance was limited. The association between nitrate and Legionella spp. abundance was disinfectant regimes dependent, while dissolved organic carbon exhibited a concentration dependent response type (i.e., positive and negative association). In chloraminated systems, Legionella spp. abundance was positively associated with ammonia and nitrate, highlighting the critical role of nitrification. Here, it appears that pH likely influences the initial colonization of Legionella spp. while ammonia governs its abundance in drinking water. Overall, this study demonstrates that integrated water chemistry and parameter-specific nonlinear effects collectively explain persistence of Mycobacterium spp. and Legionella spp. in drinking water systems. Synopsis This study elucidates the integrative impact of water chemistry and the nonlinear responses of individual water chemistry parameters on the occurrence and abundance of Mycobacterium spp. and Legionella spp. in drinking water using interpretable machine learning. TOC

  PublisherDOI

• Production and fate of macroalgal carbon in the ocean: How much do macroalgal organics matter?

  Limnology and Oceanography Letters · 2025-07-25 · 3 citations

  articleOpen accessSenior author

  Abstract Global carbon sequestration by macroalgae is hypothesized to rival rates in other blue carbon ecosystems. However, quantifying macroalgal carbon sequestration is challenging as it is hypothesized to occur outside macroalgal ecosystems, with 73% of sequestration occurring when dissolved organic carbon (DOC) is exported to deep ocean waters. In part due to the complexity of tracking carbon from coastal ecosystems to deep waters, large uncertainties remain about the rate of macroalgal carbon sequestration and its fate in the ocean. We present a synthesis of literature on macroalgal carbon cycling and place it in the context of the marine carbon cycle with a focus on DOC. Synthesis and critiquing of current estimates, including through a case study, indicates that uncertainty around all macroalgal carbon cycle terms remains high. To reduce uncertainty, we recommend developing and comparing estimates made via independent methods including by modeling, remote sensing, and using geochemical tracers.

  PublisherOA PDFDOI

• Building plumbing influences the microdiversity and community assembly of the drinking water microbiome

  Water Research · 2025-02-06 · 5 citations

  article
  PublisherDOI

• The distribution of subsurface microplastics in the ocean

  Nature · 2025-04-30 · 192 citations

  articleOpen accessSenior author

  Marine plastic pollution is a global issue, with microplastics (1 µm–5 mm) dominating the measured plastic count1,2. Although microplastics can be found throughout the oceanic water column3,4, most studies collect microplastics from surface waters (less than about 50-cm depth) using net tows5. Consequently, our understanding of the microplastics distribution across ocean depths is more limited. Here we synthesize depth-profile data from 1,885 stations collected between 2014 and 2024 to provide insights into the distribution and potential transport mechanisms of subsurface (below about 50-cm depth, which is not usually sampled by traditional practices3,6) microplastics throughout the oceanic water column. We find that the abundances of microplastics range from 10−4 to 104 particles per cubic metre. Microplastic size affects their distribution; the abundance of small microplastics (1 µm to 100 µm) decreases gradually with depth, indicating a more even distribution and longer lifespan in the water column compared with larger microplastics (100 µm to 5,000 µm) that tend to concentrate at the stratified layers. Mid-gyre accumulation zones extend into the subsurface ocean but are concentrated in the top 100 m and predominantly consist of larger microplastics. Our analysis suggests that microplastics constitute a measurable fraction of the total particulate organic carbon, increasing from 0.1% at 30 m to 5% at 2,000 m. Although our study establishes a global benchmark, our findings underscore that the lack of standardization creates substantial uncertainties, making it challenging to advance our comprehension of the distribution of microplastics and its impact on the oceanic environment. Global data collected between 2014 and 2024 provide insights into the distribution and potential transport mechanisms of subsurface microplastics throughout the oceanic water column.

  PublisherOA PDFDOI

• Plastics in the marine carbon cycle

  Nature Sustainability · 2025-09-18 · 1 citations

  article1st authorCorresponding
  PublisherDOI

Recent grants

• EAGER: Collaborative Research: Assessing the contribution of plastics to marine particulate organic carbon

  NSF · $243k · 2021–2024

• Collaborative Research: RUI: The Pulse-Shunt Concept: A Conceptual Framework for Quantifying and Forecasting Watershed DOM Fluxes and Transformations at the MacroSystem Scale

  NSF · $342k · 2014–2018

• Collaborative Research: Linking microbial diversity, gene expression, and the transformation of terrestrial organic matter in major U.S. rivers

  NSF · $263k · 2017–2020

• Collaborative Research: Linking microbial diversity, gene expression, and the transformation of terrestrial organic matter in major U.S. rivers

  NSF · $422k · 2015–2018

• Collaborative Research: CBET: The role of sunlight in determining the fate and microbial impact of microplastics in surface waters

  NSF · $330k · 2019–2024

Frequent coauthors

• Thorsten Dittmar

  Helmholtz Institute for Functional Marine Biodiversity

  84 shared

• Robert G. M. Spencer

  Florida State University

  79 shared

• Peter A. Raymond

  51 shared

• Kenneth Mopper

  Old Dominion University

  38 shared

• Anne M. Kellerman

  National High Magnetic Field Laboratory

  34 shared

• Jason B. Fellman

  University of Alaska Southeast

  34 shared

• Sasha Wagner

  Rensselaer Polytechnic Institute

  30 shared

• Amy D. Holt

  National High Magnetic Field Laboratory

  29 shared

Labs

• Developmental Neuropsychobiology LaboratoryPI

Awards & honors

• 2023 TIER1 Awardees