Beschreibung: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bundy, R. M., Tagliabue, A., Hawco, N. J., Morton, P. L., Twining, B. S., Hatta, M., Noble, A. E., Cape, M. R., John, S. G., Cullen, J. T., & Saito, M. A. Elevated sources of cobalt in the Arctic Ocean. Biogeosciences, 17(19), (2020): 4745-4767, doi:10.5194/bg-17-4745-2020.

Beschreibung: Cobalt (Co) is an important bioactive trace metal that is the metal cofactor in cobalamin (vitamin B12) which can limit or co-limit phytoplankton growth in many regions of the ocean. Total dissolved and labile Co measurements in the Canadian sector of the Arctic Ocean during the U.S. GEOTRACES Arctic expedition (GN01) and the Canadian International Polar Year GEOTRACES expedition (GIPY14) revealed a dynamic biogeochemical cycle for Co in this basin. The major sources of Co in the Arctic were from shelf regions and rivers, with only minimal contributions from other freshwater sources (sea ice, snow) and eolian deposition. The most striking feature was the extremely high concentrations of dissolved Co in the upper 100 m, with concentrations routinely exceeding 800 pmol L−1 over the shelf regions. This plume of high Co persisted throughout the Arctic basin and extended to the North Pole, where sources of Co shifted from primarily shelf-derived to riverine, as freshwater from Arctic rivers was entrained in the Transpolar Drift. Dissolved Co was also strongly organically complexed in the Arctic, ranging from 70 % to 100 % complexed in the surface and deep ocean, respectively. Deep-water concentrations of dissolved Co were remarkably consistent throughout the basin (∼55 pmol L−1), with concentrations reflecting those of deep Atlantic water and deep-ocean scavenging of dissolved Co. A biogeochemical model of Co cycling was used to support the hypothesis that the majority of the high surface Co in the Arctic was emanating from the shelf. The model showed that the high concentrations of Co observed were due to the large shelf area of the Arctic, as well as to dampened scavenging of Co by manganese-oxidizing (Mn-oxidizing) bacteria due to the lower temperatures. The majority of this scavenging appears to have occurred in the upper 200 m, with minimal additional scavenging below this depth. Evidence suggests that both dissolved Co (dCo) and labile Co (LCo) are increasing over time on the Arctic shelf, and these limited temporal results are consistent with other tracers in the Arctic. These elevated surface concentrations of Co likely lead to a net flux of Co out of the Arctic, with implications for downstream biological uptake of Co in the North Atlantic and elevated Co in North Atlantic Deep Water. Understanding the current distributions of Co in the Arctic will be important for constraining changes to Co inputs resulting from regional intensification of freshwater fluxes from ice and permafrost melt in response to ongoing climate change.

Beschreibung: This work was supported by National Science Foundation Ocean Sciences (NSF OCE) grants (grant nos. 1435056, 1736599, and 1924554) to Mak A. Saito, as well as by a Woods Hole Oceanographic Institution Postdoctoral Scholar grant to Randelle M. Bundy and Mattias R. Cape. Mariko Hatta was supported by NSF OCE grant no. 1439253. Alessandro Tagliabue was supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (BYONIC, grant no. 724289). Benjamin S. Twining was supported by NSF OCE grant no. 1435862. Peter L. Morton was supported by NSF OCE grant no. 1436019, and a portion of the work was completed at the NHMFL, which is supported by the National Science Foundation through DMR-1644779 and the State of Florida. Jay T. Cullen was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada and an International Polar Year (IPY) Canada grant.

Beschreibung: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Tarrant, E., P Riboldi, G., McIlvin, M. R., Stevenson, J., Barwinska-Sendra, A., Stewart, L. J., Saito, M. A., & Waldron, K. J. Copper stress in staphylococcus aureus leads to adaptive changes in central carbon metabolism. Metallomics, 11, (2019): 183-200, doi: 10.1039/C8MT00239H.

Beschreibung: Copper toxicity has been a long-term selection pressure on bacteria due to its presence in the environment and its use as an antimicrobial agent by grazing protozoa, by phagocytic cells of the immune system, and in man-made medical and commercial products. There is recent evidence that exposure to increased copper stress may have been a key driver in the evolution and spread of methicillin-resistant Staphylococcus aureus, a globally important pathogen that causes significant mortality and morbidity worldwide. Yet it is unclear how S. aureus physiology is affected by copper stress or how it adapts in order to be able to grow in the presence of excess copper. Here, we have determined quantitatively how S. aureus alters its proteome during growth under copper stress conditions, comparing this adaptive response in two different types of growth regime. We found that the adaptive response involves induction of the conserved copper detoxification system as well as induction of enzymes of central carbon metabolism, with only limited induction of proteins involved in the oxidative stress response. Further, we identified a protein that binds copper inside S. aureus cells when stressed by copper excess. This copper-binding enzyme, a glyceraldehyde-3-phosphate dehydrogenase essential for glycolysis, is inhibited by copper in vitro and inside S. aureus cells. Together, our data demonstrate that copper stress leads to the inhibition of glycolysis in S. aureus, and that the bacterium adapts to this stress by altering its central carbon utilisation pathways.

Beschreibung: KJW and ET were supported by a Sir Henry Dale Fellowship (to KJW) funded by the Wellcome Trust and the Royal Society (098375/Z/12/Z), and GPR was funded by a CAPES Science Without Borders scholarship (BEX 2445/13-1). JS (BB/F015895/1) and ABS (BB/J014516/1) were supported by BBSRC PhD studentships, and LS was supported by a Newcastle University Research Excellence Academy PhD studentship (05MREA). MAS was supported by the Gordon and Betty Moore Foundation Grant (GBM3782). We also thank Prof. Simon Foster (Sheffield, UK) for the gift of S. aureus strain SH1000, and Dr Julie Morrissey (Leicester, UK) for phage φ11.

Beschreibung: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Diaz, J. M., Plummer, S., Hansel, C. M., Andeer, P. F., Saito, M. A., & McIlvin, M. R. NADPH-dependent extracellular superoxide production is vital to photophysiology in the marine diatom Thalassiosira oceanica. Proceedings of the National Academy of Sciences of the United States of America, 116 (33), (2019): 16448-16453, doi: 10.1073/pnas.1821233116.

Beschreibung: Reactive oxygen species (ROS) like superoxide drive rapid transformations of carbon and metals in aquatic systems and play dynamic roles in biological health, signaling, and defense across a diversity of cell types. In phytoplankton, however, the ecophysiological role(s) of extracellular superoxide production has remained elusive. Here, the mechanism and function of extracellular superoxide production by the marine diatom Thalassiosira oceanica are described. Extracellular superoxide production in T. oceanica exudates was coupled to the oxidation of NADPH. A putative NADPH-oxidizing flavoenzyme with predicted transmembrane domains and high sequence similarity to glutathione reductase (GR) was implicated in this process. GR was also linked to extracellular superoxide production by whole cells via quenching by the flavoenzyme inhibitor diphenylene iodonium (DPI) and oxidized glutathione, the preferred electron acceptor of GR. Extracellular superoxide production followed a typical photosynthesis-irradiance curve and increased by 30% above the saturation irradiance of photosynthesis, while DPI significantly impaired the efficiency of photosystem II under a wide range of light levels. Together, these results suggest that extracellular superoxide production is a byproduct of a transplasma membrane electron transport system that serves to balance the cellular redox state through the recycling of photosynthetic NADPH. This photoprotective function may be widespread, consistent with the presence of putative homologs to T. oceanica GR in other representative marine phytoplankton and ocean metagenomes. Given predicted climate-driven shifts in global surface ocean light regimes and phytoplankton community-level photoacclimation, these results provide implications for future ocean redox balance, ecological functioning, and coupled biogeochemical transformations of carbon and metals.

Beschreibung: This work was supported by a postdoctoral fellowship from the Ford Foundation (to J.M.D.), the National Science Foundation (NSF) under grants OCE 1225801 (to J.M.D.) and OCE 1246174 (to C.M.H.), a Junior Faculty Seed Grant from the University of Georgia Research Foundation (to J.M.D.), and a National Science Foundation Graduate Research Fellowship (to S.P.). The FIRe was purchased through a NSF equipment improvement grant (1624593).The authors thank Melissa Soule for assistance with LC/MS/MS analysis of peptide samples.

Beschreibung: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bianchi, T. S., Anand, M., Bauch, C. T., Canfield, D. E., De Meester, L., Fennel, K., Groffman, P. M., Pace, M. L., Saito, M., & Simpson, M. J. Ideas and perspectives: biogeochemistry - some key foci for the future. Biogeosciences, 18(10), (2021): 3005–3013, https://doi.org/10.5194/bg-18-3005-2021.

Beschreibung: Biogeochemistry has an important role to play in many environmental issues of current concern related to global change and air, water, and soil quality. However, reliable predictions and tangible implementation of solutions, offered by biogeochemistry, will need further integration of disciplines. Here, we refocus on how further developing and strengthening ties between biology, geology, chemistry, and social sciences will advance biogeochemistry through (1) better incorporation of mechanisms, including contemporary evolutionary adaptation, to predict changing biogeochemical cycles, and (2) implementing new and developing insights from social sciences to better understand how sustainable and equitable responses by society are achieved. The challenges for biogeochemists in the 21st century are formidable and will require both the capacity to respond fast to pressing issues (e.g., catastrophic weather events and pandemics) and intense collaboration with government officials, the public, and internationally funded programs. Keys to success will be the degree to which biogeochemistry can make biogeochemical knowledge more available to policy makers and educators about predicting future changes in the biosphere, on timescales from seasons to centuries, in response to climate change and other anthropogenic impacts. Biogeochemistry also has a place in facilitating sustainable and equitable responses by society.

Beschreibung: TSB was supported in part by the Beverly Thompson Endowed Chair in Geological Sciences; MJS acknowledges support from the Natural Sciences and Engineering Research Council via a Tier 1 Canada Research Chair in Integrative Molecular Biogeochemistry.

Beschreibung: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Cohen, N. R., Noble, A. E., Moran, D. M., McIlvin, M. R., Goepfert, T. J., Hawco, N. J., German, C. R., Horner, T. J., Lamborg, C. H., McCrow, J. P., Allen, A. E., & Saito, M. A. Hydrothermal trace metal release and microbial metabolism in the northeastern Lau Basin of the South Pacific Ocean. Biogeosciences, 18(19), (2021): 5397–5422, https://doi.org/10.5194/bg-18-5397-2021.

Beschreibung: Bioactive trace metals are critical micronutrients for marine microorganisms due to their role in mediating biological redox reactions, and complex biogeochemical processes control their distributions. Hydrothermal vents may represent an important source of metals to microorganisms, especially those inhabiting low-iron waters, such as in the southwest Pacific Ocean. Previous measurements of primordial 3He indicate a significant hydrothermal source originating in the northeastern (NE) Lau Basin, with the plume advecting into the southwest Pacific Ocean at 1500–2000 m depth (Lupton et al., 2004). Studies investigating the long-range transport of trace metals associated with such dispersing plumes are rare, and the biogeochemical impacts on local microbial physiology have not yet been described. Here we quantified dissolved metals and assessed microbial metaproteomes across a transect spanning the tropical and equatorial Pacific with a focus on the hydrothermally active NE Lau Basin and report elevated iron and manganese concentrations across 441 km of the southwest Pacific. The most intense signal was detected near the Mangatolo Triple Junction (MTJ) and Northeast Lau Spreading Center (NELSC), in close proximity to the previously reported 3He signature. Protein content in distal-plume-influenced seawater, which was high in metals, was overall similar to background locations, though key prokaryotic proteins involved in metal and organic uptake, protein degradation, and chemoautotrophy were abundant compared to deep waters outside of the distal plume. Our results demonstrate that trace metals derived from the NE Lau Basin are transported over appreciable distances into the southwest Pacific Ocean and that bioactive chemical resources released from submarine vent systems are utilized by surrounding deep-sea microbes, influencing both their physiology and their contributions to ocean biogeochemical cycling.

Beschreibung: This research has been supported by the National Science Foundation (grant nos. 1031271, 1924554, 1850719, 1736599, and 1851007); the Gordon and Betty Moore Foundation (grant no. 3782); and the Simons Foundation (grant no. 544236).

Beschreibung: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Chmiel, R., Lanning, N., Laubach, A., Lee, J.-M., Fitzsimmons, J., Hatta, M., Jenkins, W., Lam, P., McIlvin, M., Tagliabue, A., & Saito, M. Major processes of the dissolved cobalt cycle in the north and equatorial Pacific Ocean. Biogeosciences, 19(9), (2022): 2365–2395, https://doi.org/10.5194/bg-19-2365-2022.

Beschreibung: Over the past decade, the GEOTRACES and wider trace metal geochemical community has made substantial contributions towards constraining the marine cobalt (Co) cycle and its major biogeochemical processes. However, few Co speciation studies have been conducted in the North and equatorial Pacific Ocean, a vast portion of the world's oceans by volume and an important end-member of deep thermohaline circulation. Dissolved Co (dCo) samples, including total dissolved and labile Co, were measured at-sea during the GEOTRACES Pacific Meridional Transect (GP15) expedition along the 152∘ W longitudinal from 56∘ N to 20∘ S. Along this transect, upper-ocean dCo (σ0〈26) was linearly correlated with dissolved phosphate (slope = 82±3, µmol : mol) due to phytoplankton uptake and remineralization. As depth increased, dCo concentrations became increasingly decoupled from phosphate concentrations due to co-scavenging with manganese oxide particles in the mesopelagic. The transect revealed an organically bound coastal source of dCo to the Alaskan Stream associated with low-salinity waters. An intermediate-depth hydrothermal flux of dCo was observed off the Hawaiian coast at the Loihi Seamount, and the elevated dCo was correlated with potential xs3He at and above the vent site; however, the Loihi Seamount likely did not represent a major source of Co to the Pacific basin. Elevated concentrations of dCo within oxygen minimum zones (OMZs) in the equatorial North and South Pacific were consistent with the suppression of oxidative scavenging, and we estimate that future deoxygenation could increase the OMZ dCo inventory by 18 % to 36 % over the next century. In Pacific Deep Water (PDW), a fraction of elevated ligand-bound dCo appeared protected from scavenging by the high biogenic particle flux in the North Pacific basin. This finding is counter to previous expectations of low dCo concentrations in the deep Pacific due to scavenging over thermohaline circulation. Compared to a Co global biogeochemical model, the observed transect displayed more extreme inventories and fluxes of dCo than predicted by the model, suggesting a highly dynamic Pacific Co cycle.

Beschreibung: This research has been supported by the National Science Foundation (grant nos. OCE-1736599, OCE-1756138, OCE-1657781 and OCE-1736601) and the Horizon 2020 research and innovation program (BYONIC; grant no. 724289).

Beschreibung: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Mazzotta, M. G., McIlvin, M. R., & Saito, M. A. Characterization of the Fe metalloproteome of a ubiquitous marine heterotroph, Pseudoalteromonas (BB2-AT2): multiple bacterioferritin copies enable significant Fe storage. Metallomics, (2020), doi:10.1039/d0mt00034e.

Beschreibung: Fe is a critical nutrient to the marine biological pump, which is the process that exports photosynthetically fixed carbon in the upper ocean to the deep ocean. Fe limitation controls photosynthetic activity in major regions of the oceans, and the subsequent degradation of exported photosynthetic material is facilitated particularly by marine heterotrophic bacteria. Despite their importance in the carbon cycle and the scarcity of Fe in seawater, the Fe requirements, storage and cytosolic utilization of these marine heterotrophs has been less studied. Here, we characterized the Fe metallome of Pseudoalteromonas (BB2-AT2). We found that with two copies of bacterioferritin (Bfr), Pseudoalteromonas possesses substantial capacity for luxury uptake of Fe. Fe : C in the whole cell metallome was estimated (assuming C : P stoichiometry ∼51 : 1) to be between ∼83 μmol : mol Fe : C, ∼11 fold higher than prior marine bacteria surveys. Under these replete conditions, other major cytosolic Fe-associated proteins were observed including superoxide dismutase (SodA; with other metal SOD isoforms absent under Fe replete conditions) and catalase (KatG) involved in reactive oxygen stress mitigation and aconitase (AcnB), succinate dehydrogenase (FrdB) and cytochromes (QcrA and Cyt1) involved in respiration. With the aid of singular value decomposition (SVD), we were able to computationally attribute peaks within the metallome to specific metalloprotein contributors. A putative Fe complex TonB transporter associated with the closely related Alteromonas bacterium was found to be abundant within the Pacific Ocean mesopelagic environment. Despite the extreme scarcity of Fe in seawater, the marine heterotroph Pseudoalteromonas has expansive Fe storage capacity and utilization strategies, implying that within detritus and sinking particles environments, there is significant opportunity for Fe acquisition. Together these results imply an evolved dedication of marine Pseudoalteromonas to maintaining an Fe metalloproteome, likely due to its dependence on Fe-based respiratory metabolism.

Beschreibung: M. G. M. was supported by the Camille and Henry Dreyfus Foundation Environmental Chemistry Postdoctoral Fellowship. We thank Kay Bidle (Rutgers University) for providing a culture of Pseudoalteromonas (BB2-AT2). We also thank Dawn Moran (WHOI) and Noelle Held (WHOI-MIT) for culturing assistance. We appreciate the Captain and Crew of the R/V Kilo Moana, and the many involved in the METZYME expedition sampling efforts. Discussions with Kevin Waldron (Newcastle University), Alison Butler (University of California, Santa Barbara), Lauren Manck (Scripps Institution of Oceanography), Randie Bundy (University of Washington) and Jake Gebbie (WHOI) were much appreciated. Funding for this research was provided by the Gordon and Betty Moore Foundation (3782), and NSF-OCE 1658030, 1736599, 1657766, 1924554, 1850719, 1924554.

Beschreibung: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Held, N. A., Webb, E. A., McIlvin, M. M., Hutchins, D. A., Cohen, N. R., Moran, D. M., Kunde, K., Lohan, M. C., Mahaffey, C., Woodward, E. M. S., & Saito, M. A. Co-occurrence of fe and P stress in natural populations of the marine diazotroph Trichodesmium. Biogeosciences, 17(9), (2020): 2537-2551, doi:10.5194/bg-17-2537-2020.

Beschreibung: Trichodesmium is a globally important marine microbe that provides fixed nitrogen (N) to otherwise N-limited ecosystems. In nature, nitrogen fixation is likely regulated by iron or phosphate availability, but the extent and interaction of these controls are unclear. From metaproteomics analyses using established protein biomarkers for nutrient stress, we found that iron–phosphate co-stress is the norm rather than the exception for Trichodesmium colonies in the North Atlantic Ocean. Counterintuitively, the nitrogenase enzyme was more abundant under co-stress as opposed to single nutrient stress. This is consistent with the idea that Trichodesmium has a specific physiological state during nutrient co-stress. Organic nitrogen uptake was observed and occurred simultaneously with nitrogen fixation. The quantification of the phosphate ABC transporter PstA combined with a cellular model of nutrient uptake suggested that Trichodesmium is generally confronted by the biophysical limits of membrane space and diffusion rates for iron and phosphate acquisition in the field. Colony formation may benefit nutrient acquisition from particulate and organic sources, alleviating these pressures. The results highlight that to predict the behavior of Trichodesmium, both Fe and P stress must be evaluated simultaneously.

Beschreibung: This research has been supported by the National Science Foundation (Division of Graduate Education (grant nos. 1122274), Division of Ocean Sciences (grant nos. 1657755, 1657757, and 1851222), Directorate for Geosciences (grant no. 1639714)), the Gordon and Betty Moore Foundation (grant no. 3782), and the Natural Environment Research Council (NERC) (grant nos. NE/N001079/1 and NE/N001125/1).

Beschreibung: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bayer, B., Saito, M. A., McIlvin, M. R., Lucker, S., Moran, D. M., Lankiewicz, T. S., Dupont, C. L., & Santoro, A. E. (2020). Metabolic versatility of the nitrite-oxidizing bacterium Nitrospira marina and its proteomic response to oxygen-limited conditions. Isme Journal, doi:10.1038/s41396-020-00828-3.

Beschreibung: The genus Nitrospira is the most widespread group of nitrite-oxidizing bacteria and thrives in diverse natural and engineered ecosystems. Nitrospira marina Nb-295T was isolated from the ocean over 30 years ago; however, its genome has not yet been analyzed. Here, we investigated the metabolic potential of N. marina based on its complete genome sequence and performed physiological experiments to test genome-derived hypotheses. Our data confirm that N. marina benefits from additions of undefined organic carbon substrates, has adaptations to resist oxidative, osmotic, and UV light-induced stress and low dissolved pCO2, and requires exogenous vitamin B12. In addition, N. marina is able to grow chemoorganotrophically on formate, and is thus not an obligate chemolithoautotroph. We further investigated the proteomic response of N. marina to low (∼5.6 µM) O2 concentrations. The abundance of a potentially more efficient CO2-fixing pyruvate:ferredoxin oxidoreductase (POR) complex and a high-affinity cbb3-type terminal oxidase increased under O2 limitation, suggesting a role in sustaining nitrite oxidation-driven autotrophy. This putatively more O2-sensitive POR complex might be protected from oxidative damage by Cu/Zn-binding superoxide dismutase, which also increased in abundance under low O2 conditions. Furthermore, the upregulation of proteins involved in alternative energy metabolisms, including Group 3b [NiFe] hydrogenase and formate dehydrogenase, indicate a high metabolic versatility to survive conditions unfavorable for aerobic nitrite oxidation. In summary, the genome and proteome of the first marine Nitrospira isolate identifies adaptations to life in the oxic ocean and provides insights into the metabolic diversity and niche differentiation of NOB in marine environments.

Beschreibung: We thank John B. Waterbury and Frederica Valois for providing the culture of Nitrospira marina Nb-295T and for continued advice about cultivation. The N. marina genome was sequenced as part of US Department of Energy Joint Genome Institute Community Sequencing Project 1337 to CLD, AES, and MAS in collaboration with the user community. We thank Claus Pelikan for bioinformatic assistance. This research was supported by a Simons Foundation Early Career Investigator in Marine Microbiology and Evolution Award (345889) and US National Science Foundation (NSF) award OCE-1924512 to AES. Proteomics analysis was supported by NSF awards OCE-1924554 and OCE-1850719, and NIH award R01GM135709 to MAS. BB was supported by the Austrian Science Fund (FWF) Project Number: J4426-B (“The influence of nitrifiers on the oceanic carbon cycle”), SL by the Netherlands Organization for Scientific Research (NWO) grant 016.Vidi.189.050, and CLD by NSF award OCE-125999.

Beschreibung: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Saunders, J. K., McIlvin, M. R., Dupont, C. L., Kaul, D., Moran, D. M., Horner, T., Laperriere, S. M., Webb, E. A., Bosak, T., Santoro, A. E., & Saito, M. A. Microbial functional diversity across biogeochemical provinces in the central Pacific Ocean. Proceedings of the National Academy of Sciences of the United States of America, 119(37),(2022): e2200014119, https://doi.org/10.1073/pnas.2200014119.

Beschreibung: Enzymes catalyze key reactions within Earth’s life-sustaining biogeochemical cycles. Here, we use metaproteomics to examine the enzymatic capabilities of the microbial community (0.2 to 3 µm) along a 5,000-km-long, 1-km-deep transect in the central Pacific Ocean. Eighty-five percent of total protein abundance was of bacterial origin, with Archaea contributing 1.6%. Over 2,000 functional KEGG Ontology (KO) groups were identified, yet only 25 KO groups contributed over half of the protein abundance, simultaneously indicating abundant key functions and a long tail of diverse functions. Vertical attenuation of individual proteins displayed stratification of nutrient transport, carbon utilization, and environmental stress. The microbial community also varied along horizontal scales, shaped by environmental features specific to the oligotrophic North Pacific Subtropical Gyre, the oxygen-depleted Eastern Tropical North Pacific, and nutrient-rich equatorial upwelling. Some of the most abundant proteins were associated with nitrification and C1 metabolisms, with observed interactions between these pathways. The oxidoreductases nitrite oxidoreductase (NxrAB), nitrite reductase (NirK), ammonia monooxygenase (AmoABC), manganese oxidase (MnxG), formate dehydrogenase (FdoGH and FDH), and carbon monoxide dehydrogenase (CoxLM) displayed distributions indicative of biogeochemical status such as oxidative or nutritional stress, with the potential to be more sensitive than chemical sensors. Enzymes that mediate transformations of atmospheric gases like CO, CO2, NO, methanethiol, and methylamines were most abundant in the upwelling region. We identified hot spots of biochemical transformation in the central Pacific Ocean, highlighted previously understudied metabolic pathways in the environment, and provided rich empirical data for biogeochemical models critical for forecasting ecosystem response to climate change.

Beschreibung: Funding for this research was provided by the Gordon and Betty Moore Foundation (grants 3782 and 8453), the US NSF (NSF grants OCE-1924554, 2123055, 2125063, 2048774, and 2026933), the Center for Chemical Currencies on a Microbial Planet (NSF grant OCE-2019589), and the US NIH General Medicine (grant GM135709-01A1). J.K.S. was supported by a NASA Postdoctoral Program Fellowship with the NASA Astrobiology Program, administered by Universities Space Research Association under contract with NASA. A.E.S. was supported by the Sloan Foundation, the Simons Foundation, and NSF grant OCE-1437310. A portion of this research used resources at the US Department of Energy JGI sponsored by the Office of Biological and Environmental Research and operated under contract DE-AC02-05CH11231 (JGI). C.L.D. and D.K. were supported by NSF grants OCE-1558453 and OCE-2049299. T.H. was supported by NSF grant OCE-2023456.