Project Proposal: Redfield Ratios at Hydrothermal Vent Communities

Question: Does the elemental ratio of organic matter in chemosynthetic communities at deep-sea hydrothermal vents differ from the surface-water Redfield ratio (106C:16N:1P)?

Goal: The goal is to determine if the Redfield Ratio, an empirical constant calculated based on photosynthetic plankton, is a universal constant that holds for autotrophic chemolithotrophic deep-sea ecosystems.

Objective: Sample and analyze [how?] microbial mats, tube worms, and surrounding water to see what microbes are present surrounding hydrothermal vent sites such as Juan de Fuca’s Axial Seamount (depth: 1400-1500m).

Scientific Importance: 

The Redfield ratio (Redfield, 1934) was measured from photosynthetic phytoplankton, and it is not yet known if it represents a universal range, or is simply a product of surface ocean conditions. Chemosynthetic hydrothermal vent communities thrive in high levels of pressure, head and mineral-rich conditions with no sunlight (Artigue et al., 2025). If the ratio stands in these conditions it would suggest how life is created, regardless of energy sources (Holden et al., 2015). If the ratio is different, that would indicate how this environment changes the organism's stoichiometry (Coral et al., 2025), revealing a new sector of biological chemistry operating under different conditions than what has been studied. This has broader implications for deep-sea carbon cycling (Orcutt et al., 2020) and the origin of life debate (Hidetaka Nomaki et al., 2024, Holden et al., 2015, MacPherson, 2026). 

Importance for deep-sea policies: Deep-sea mining and harvesting operations will disturb or destroy vent communities, currently there are no solidified protections or regulations for deep sea environments. We have a limited understanding of the biodiversity of deep sea ecosystems, and there are no protections or restrictions on development in the deep sea. The Redfield ratio is the biological law used to calculate the amount of organic matter moving through the ocean system, if the vent communities are found to operate under a different ratio (Martiny et al., 2013, Matsumoto et al., 2020), current models are miscalculating the influence vent communities have on global geochemical cycles (Coral et al., 2025, Holden et al., 2015). This would make current assessments flawed. Establishing an accurate ratio in vent communities will give regulations an empirical basis for evaluating the costs of deep sea exploitation (Hidetaka Nomaki et al., 2024). Currently, hydrothermal vents are categorized into two ecosystems, of black smokes (iron sulfide rich, hotter, faster moving water) and white smokers (barium, calcium and silicon rich, cooler, slower moving water) (Kelley et al., 2005). These differences may influence the ratios present, so it is vital to take both environments into account (Arizona State University, 2026). 

Approach: In this one-year project, I will first, conduct a literature review to compare known Redfield ratio deviations for chemosynthetic particulates, microscopic organic matter produced by microbes and bacteria (2 mo.). Second, I will collect field samples at the Lost City Hydrothermal Field, alkaline hydrothermal vents (Kelley, 2005), an active submarine volcano 480 km west of the Oregon coast. This will be done in partnership with the Ocean Observation Initiative (OOI) Cruise using ROV Jason to collect microbial mat samples, macrofauna tissue, and vent fluid. Samples will also be used from ‘El Gordo,’ a black smoker on the Juan De Fuca ridge, which has a stationed sensor over the active vent (2 mo). Third, I will filter and analyze the samples using OOI protocols (2 mon). Specifically, I will spend conducting Elemental Analyzer - Isotope Ratio Mass Spectrometry (EA-IRMS) to measure bulk isotope ratios. I will then calculate the isotope ratio(s), and interpret the results. Analysis will be done using R Studio to create data visualizations and run statistical analysis comparing Redfield ratio values (2 mo). Finally, I will prepare to present my findings through a written report with intentions to present at a research conference. The data will be added to the OOI data platform (2 mo). 

Expected Results: 

Hypothesis: The elemental ratio of organic matter in hydrothermal vent communities will differ from the standard Redfield ratio (106C:16N:1P), with the deviation varying between black and white smoker ecosystems due to their distinct geochemical conditions.

If results are consistent with the hypothesis: Black smoker communities show an elevated C:P ratios relative to Redfield, driven by phosphorus limitation in high-temperature mineral-rich fluid. At white smoker communities there would be lower C:N ratios which are closer to bacterial biomass stoichiometry (4–6C:1N) reflecting N-rich, dominated biomass from slower-metabolizing chemolithotrophs. δ¹³C stable isotope levels confirm vent-derived carbon fixation (depleted, −25 to −35%) in both environments. This outcome would suggest that the Redfield ratio is not a universal biological constant, but is shaped by the geochemical environment in which the organism is developing. It would establish that chemosynthetic ecosystems operate under fundamentally different stoichiometric rules, expanding understanding of how life organizes itself beyond photosynthetic systems and calling for an updated model in deep sea environments. For developing policy, it would change the environmental impact assessments for deep-sea mining that cannot rely on Redfield-based models, and the altered vent stoichiometry must be applied when calculating biogeochemical and carbon cycling(Arizona State University, 2026, Orcutt et al., 2020).

If results are not consistent with my hypothesis: If the vent types both fall within the known ranges of the Redfield ratio (78–195C:13–28N:1P) with no statistically significant difference between communities, this would suggest that standard biological chemistry overrides the extreme geochemical conditions in these ecosystems. This result would strengthen the Redfield ratio across energy sources and environments, and would also suggest that existing biogeochemical models are applicable to deep-sea ecosystems than currently assumed, providing a solid foundation for deep-sea environmental surveys (Orcutt et al., 2020).