Ocean carbon uptake, cycling and sequestration are variable on all time scales, and modulated by an interplay of complex physical and biogeochemical drivers, including anthropogenic CO2increase and associated ocean acidification (OA). OA at Station ALOHA is intensified in the subsurface due to increases in both natural and anthropogenic carbon pools, and their interactions. Enhanced subsurface change is found for all OA indicator variables. This includes both the parameters who have previously been reported to be systematically impacted by nonlinear interactions between anthropogenic and natural carbon pools ([H+], pCO2, Revelle Factor), but also those who do not show this generalized response in the ocean interior (pH, aragonite saturation state (ΩAr)). Different parameters have trend maxima in each of the three water masses in the upper 500 m, driven by different mechanisms. Enhanced acidification is noted in the North Pacific Tropical Water (NPTW) between 2015-2020. This steepening is due to the interplay of a circulation slowdown during a prolonged negative phase of the North Pacific Gyre Oscillation (NPGO) with other anomalous atmospheric forcing that altered source water chemistry, including large-scale freshening. Long-term sustained increased acidification is also associated with freshening and cooling in the Subsurface Salinity Minimum (SSM) over the whole time-series, with considerable oxygen loss and nutrient increases. In the North Pacific Intermediate Water (NPIW), a well-documented long-term circulation slowdown has led to enhanced CO2 ingrowth from remineralization, buffered by increasing carbonate dissolution. Local changes seem to play a smaller role than circulation and source water changes. In two water masses, enhanced acidification is associated with cooling and freshening, providing new insights on how OA can accelerate beyond the well documented warming and souring of the ocean.

Unicellular plankton form the foundation of the marine food web, driving carbon fixation and cycling essential biogeochemical elements in marine ecosystems. Carbon biomass, often measured as a bulk property, serves as a common "currency" for ecologists. The increasing availability of metatranscriptomic data presents an opportunity to add taxonomic and functional resolution to ecological models and yet, aligning transcript counts with carbon biomass estimates remains a challenge. Here, we combine 30 quantitative metatranscriptome samples with Imaging FlowCytobot-derived carbon biomass estimates and demonstrate a robust, proportional (log-log scale) relationship between transcript concentration and carbon biomass estimates across abundant protist taxa. Further, we show that dinoflagellates exhibit a transcript-to-biomass ratio ~ 6.4-fold higher than other protist groups, consistent with their known transcriptional divergence. These findings provide a means to address overrepresentation of dinoflagellate transcript levels in metatranscriptome data. Moreover, this study establishes an entrée for integrating metatranscriptomics into carbon biomass-based ecological models, enhancing the interpretability and applicability of transcriptomic data in ecosystem research and modeling.

Industrial activities have increased the supply of iron to the ocean, but the magnitude of anthropogenic input and its ecological consequences are not well-constrained by observations. Across four expeditions to the North Pacific transition zone, we document a repeated supply of isotopically light iron from an atmospheric source in spring, reflecting an estimated 39 ± 9 % anthropogenic contribution to the surface ocean iron budget. Expression of iron-stress genes in metatranscriptomes, and evidence for colimitation of ecosystem productivity by iron and nitrogen, indicates that enhanced iron supply should spur spring phytoplankton blooms, accelerating the seasonal drawdown of nitrate delivered by winter mixing. This effect is consistent with regional trends in satellite ocean color, which show a shorter, more intense spring bloom period, followed by an earlier arrival of oligotrophic conditions in summer. Continued iron emissions may contribute to poleward shifts in transitional marine ecosystems, compounding the anticipated impacts from ocean warming and stratification.

This study seeks to identify drivers of differences in ocean acidification (OA) rates throughout the upper ocean at Station ALOHA in the North Pacific Subtropical Gyre (NPSG). OA is intensified in the subsurface due to increases in natural and anthropogenic carbon pools, and their interactions. Enhanced subsurface trends are found for all OA indicators. This includes parameters that have previously been identified to exhibit nonlinear interactions between anthropogenic and natural carbon ([H + ], p CO 2 , pH, Revelle Factor), as well as parameters that are not subject to this response (aragonite saturation state (Ω Ar )). Different parameters have trend maxima in each of the water masses in the upper 500 m, driven by different mechanisms. Enhanced acidification is noted in the North Pacific Tropical Water (NPTW) from 2015 until 2020. This is due to the interplay of a circulation slowdown during a prolonged negative phase of the North Pacific Gyre Oscillation (NPGO) with other anomalous atmospheric forcing that altered source water chemistry, including large‐scale freshening. Sustained increased acidification is also associated with freshening and cooling in the Subsurface Salinity Minimum (SSM) over the whole time‐series, with considerable oxygen loss and nutrient increases. In the North Pacific Intermediate Water (NPIW), a well‐documented circulation slowdown has led to enhanced CO 2 ingrowth from remineralization, buffered by increasing carbonate dissolution. Local changes seem to play a smaller role. In the SSM and NPTW, enhanced acidification is associated with cooling and freshening, providing new insights on how OA can accelerate beyond the well‐documented warming and souring of the ocean.

We examined the nitrogen (N) biogeochemistry of adjacent cyclonic and anticyclonic eddies near Hawai’i in the North Pacific Subtropical Gyre (NPSG) and explored mechanisms that may sustain productivity in the cyclone after the initial intensification stage. The top of the nutricline was uplifted into the euphotic zone in the cyclone and depressed in the anticyclone. Subsurface nutrient concentrations and apparent oxygen utilization at the cyclone’s inner periphery were higher than expected from isopycnal displacement, suggesting that shallow remineralization of organic material generated excess nutrients in the subsurface. The excess nutrients may provide a supply of subsurface nutrients to sustain productivity in maturing eddies. The shallow remineralization also raises questions regarding the extent to which cyclonic eddies promote deep carbon sequestration in subtropical gyres such as the NPSG. An upward increase in nitrate 15N/14N isotope ratios below the euphotic zone, indicative of partial nitrate assimilation, coincided with negative preformed nutrients – potentially signaling heterotrophic bacterial consumption of carbon-rich (nitrogen-poor) organic material. The 15N/14N of material collected in shallow sediment traps was significantly higher in the cyclone than the anticyclone and showed correspondence to the 15N/14N ratio of the nitrate supply, which is acutely sensitive to sea level anomaly in the region. A number of approaches were applied to estimate the contribution of N2 fixation to export production; results among approaches were inconsistent, which we attribute to non-steady state conditions during our observation period.

Abstract Dinitrogen (N2) fixation supports marine life through the supply of reactive nitrogen. Recent studies suggest that particle-associated non-cyanobacterial diazotrophs (NCDs) could contribute significantly to N2 fixation contrary to the paradigm of diazotrophy as primarily driven by cyanobacterial genera. We examine the community composition of NCDs associated with suspended, slow, and fast-sinking particles in the North Pacific Subtropical Gyre. Suspended and slow-sinking particles showed a higher abundance of cyanobacterial diazotrophs than fast-sinking particles, while fast-sinking particles showed a higher diversity of NCDs including Marinobacter, Oceanobacter and Pseudomonas. Using single-cell mass spectrometry we find that Gammaproteobacteria N2 fixation rates were higher on suspended and slow-sinking particles (up to 67 ± 48.54 fmol N cell⁻¹ d⁻¹), while putative NCDs’ rates were highest on fast-sinking particles (121 ± 22.02 fmol N cell⁻¹ d⁻¹). These rates are comparable to previous diazotrophic cyanobacteria observations, suggesting that particle-associated NCDs may be important contributors to pelagic N2 fixation.

Abstract On behalf of the journal, AGU, and the scientific community, the editors of Geophysical Research Letters would like to sincerely thank those who reviewed manuscripts in 2024. The hours reading and commenting on manuscripts not only improve the manuscripts but also increase the scientific rigor of future research in the field. With the advent of AGU's data policy, many reviewers have also helped immensely to evaluate the accessibility and availability of data, and many have provided insightful comments that helped to improve the data presentation and quality. We greatly appreciate the assistance of the reviewers in advancing open science, which is a key objective of AGU's data policy. We particularly appreciate the timely reviews in light of the demands imposed by the rapid review process at Geophysical Research Letters. We received 5,225 submissions in 2024, and 5,597 reviewers contributed to their evaluation by providing 9,697 reviews in total. We deeply appreciate their contributions. We would also like to acknowledge the passing of our beloved colleague, Harihar Rajaram. An AGU Fellow and longtime affiliate of AGU's Hydrology Section, Hari was the Editor‐in‐Chief of Geophysical Research Letters since 2019, a former editor on Water Resources Research, and served on the AGU Publications Committee.

Photosynthesis fuels primary production at the base of marine food webs. Yet, in many surface ocean ecosystems, diel-driven primary production is tightly coupled to daily loss. This tight coupling raises the question: which top-down drivers predominate in maintaining persistently stable picocyanobacterial populations over longer time scales? Motivated by high-frequency surface water measurements taken in the North Pacific Subtropical Gyre (NPSG), we developed multitrophic models to investigate bottom-up and top-down mechanisms underlying the balanced control of Prochlorococcus populations. We find that incorporating photosynthetic growth with viral- and predator-induced mortality is sufficient to recapitulate daily oscillations of Prochlorococcus abundances with baseline community abundances. In doing so, we infer that grazers in this environment function as the predominant top-down factor despite high standing viral particle densities. The model-data fits also reveal the ecological relevance of light-dependent viral traits and non-canonical factors to cellular loss. Finally, we leverage sensitivity analyses to demonstrate how variation in life history traits across distinct oceanic contexts, including variation in viral adsorption and grazer clearance rates, can transform the quantitative and even qualitative importance of top-down controls in shaping Prochlorococcus population dynamics.

There are many potential approaches to marine carbon dioxide removal (mCDR), of which ocean iron fertilization (OIF) has the longest history of study. However, OIF studies to date were not primarily designed to quantify the durability of carbon (C) storage, nor how wise OIF might be as an mCDR approach. To quantify C sequestration, we introduce a metric called the “centennial tonne,” defined as 1,000 kg of C isolated from atmospheric contact for on average at least 100 years. We present the activities needed to assess OIF from a scientific and technological perspective, and additionally, how it might be responsibly studied and potentially deployed. The five activities include: field studies in the Northeast Pacific; improved modeling for field studies, data assimilation and predictions at larger scales; improvements in monitoring, reporting and verification (MRV) for C, and also MRV for tracking ecological and environmental impacts; and developing new iron sources and their delivery, to increase efficiencies and reduce costs. The fifth activity is to understand whether public and community support exists for OIF, and what governance structures might support further research and possible deployment of OIF. This article is written by a multidisciplinary experts group called Exploring Ocean Iron Solutions (ExOIS) that is organized around a responsible code of conduct. Of the mCDR approaches, OIF has the potential to be low cost, scalable, and rapidly deployable. Reducing CO2 emissions must lead the way, but there is also an urgency to decide under what conditions and whether OIF might be deployed or not.

The proportions of carbon (C), nitrogen (N), and phosphorus (P) in surface ocean particulate matter deviate greatly from the canonical Redfield Ratio (C:N:P = 106:16:1) in space and time with significant implications for global carbon storage as this matter reaches the deep ocean. Recent work has revealed clear latitudinal patterns in C:N:P, yet the relative importance of ecological, physiological, or biochemical processes in creating these patterns is unclear. We present high-resolution, concurrent measurements of particulate C:N:P, macromolecular composition, environmental conditions, and plankton community composition from a transect spanning a subtropical-subpolar boundary, the North Pacific Transition Zone. We find that the summed contribution of macromolecules to particulate C, N, and P is consistent with, and provides interpretation for, particulate C:N:P patterns. A decline in particulate C:N from the subtropical to subpolar North Pacific largely reflects an increase in the relative contribution of protein compared to carbohydrate and lipid, whereas variation in C:P and N:P correspond to shifts in protein relative to polyphosphate, DNA, and RNA. Possible causes for the corresponding trends in C:N and macromolecular composition include physiological responses and changes in community structure of phytoplankton, which represented approximately 1/3 rd of particulate C across the transect. Comparison with culture experiments and an allocation-based model of phytoplankton macromolecular composition suggest that physiological acclimation to changing nutrient supply is the most likely explanation for the latitudinal trend in C:N, offering both a mechanistic interpretation and biochemical basis for large-scale patterns in C:N:P.

The combination of taxa and size classes of phytoplankton that coexist at any location affects the structure of the marine food web and the magnitude of carbon fluxes to the deep ocean. But what controls the patterns of this community structure across environmental gradients remains unclear. Here, we focus on the North East Pacific Transition Zone, a similar to 10 degrees region of latitude straddling warm, nutrient-poor subtropical and cold, nutrient-rich subpolar gyres. Data from three cruises to the region revealed intricate patterns of phytoplankton community structure: poleward increases in the number of cell size classes; increasing biomass of picoeukaryotes and diatoms; decreases in diazotrophs and Prochlorococcus; and both increases and decreases in Synechococcus. These patterns can only be partially explained by existing theories. Using data, theory, and numerical simulations, we show that the patterns of plankton distributions across the transition zone are the result of gradients in nutrient supply rates, which control a range of complex biotic interactions. We examine how interactions such as size-specific grazing, multiple trophic strategies, shared grazing between several phytoplankton size classes and heterotrophic bacteria, and competition for multiple resources can individually explain aspects of the observed community structure. However, it is the combination of all these interactions together that is needed to explain the bulk compositional patterns in phytoplankton across the North East Pacific Transition Zone. The synthesis of multiple mechanisms is essential for us to begin to understand the shaping of community structure over large environmental gradients.

The presented pilot for the Synthesis Product for Ocean Time Series (SPOTS) includes data from 12 fixed ship-based time-series programs. The related stations represent unique open-ocean and coastal marine environments within the Atlantic Ocean, Pacific Ocean, Mediterranean Sea, Nordic Seas, and Caribbean Sea. The focus of the pilot has been placed on biogeochemical essential ocean variables: dissolved oxygen, dissolved inorganic nutrients, inorganic carbon (pH, total alkalinity, dissolved inorganic carbon, and partial pressure of CO2), particulate matter, and dissolved organic carbon. The time series used include a variety of temporal resolutions (monthly, seasonal, or irregular), time ranges (10–36 years), and bottom depths (80–6000 m), with the oldest samples dating back to 1983 and the most recent one corresponding to 2021. Besides having been harmonized into the same format (semantics, ancillary data, units), the data were subjected to a qualitative assessment in which the applied methods were evaluated and categorized. The most recently applied methods of the time-series programs usually follow the recommendations outlined by the Bermuda Time Series Workshop report (Lorenzoni and Benway, 2013), which is used as the main reference for “method recommendations by prevalent initiatives in the field”. However, measurements of dissolved oxygen and pH, in particular, still show room for improvement. Additional data quality descriptors include precision and accuracy estimates, indicators for data variability, and offsets compared to a reference and widely recognized data product for the global ocean: the GLobal Ocean Data Analysis Project (GLODAP). Generally, these descriptors indicate a high level of continuity in measurement quality within time-series programs and a good consistency with the GLODAP data product, even though robust comparisons to the latter are limited. The data are available as (i) a merged comma-separated file that is compliant with the World Ocean Circulation Experiment (WOCE) exchange format and (ii) a format dependent on user queries via the Environmental Research Division's Data Access Program (ERDDAP) server of the Global Ocean Observing System (GOOS). The pilot increases the data utility, findability, accessibility, interoperability, and reusability following the FAIR philosophy, enhancing the readiness of biogeochemical time series. It facilitates a variety of applications that benefit from the collective value of biogeochemical time-series observations and forms the basis for a sustained time-series living data product, SPOTS, complementing relevant products for the global interior ocean carbon data (GLobal Ocean Data Analysis Project), global surface ocean carbon data (Surface Ocean CO2 Atlas; SOCAT), and global interior and surface methane and nitrous oxide data (MarinE MethanE and NiTrous Oxide product). Aside from the actual data compilation, the pilot project produced suggestions for reporting metadata, implementing quality control measures, and making estimations about uncertainty. These recommendations aim to encourage the community to adopt more consistent and uniform practices for analysis and reporting and to update these practices regularly. The detailed recommendations, links to the original time-series programs, the original data, their documentation, and related efforts are available on the SPOTS website. This site also provides access to the data product (DOI: https://doi.org/10.26008/1912/bco-dmo.896862.2, Lange et al., 2024) and ancillary data.

On behalf of the journal, AGU, and the scientific community, the editors of Geophysical Research Letters would like to sincerely thank those who reviewed manuscripts for us in 2023. The hours reading and commenting on manuscripts not only improve the manuscripts, but also increase the scientific rigor of future research in the field. With the advent of AGU's data policy, many reviewers have also helped immensely to evaluate the accessibility and availability of data, and many have provided insightful comments that helped to improve the data presentation and quality. We greatly appreciate the assistance of the reviewers in advancing open science, which is a key objective of AGU's data policy. We particularly appreciate the timely reviews in light of the demands imposed by the rapid review process at Geophysical Research Letters. We received 4,512 submissions in 2023 and 5,112 reviewers contributed to their evaluation by providing 8,587 reviews in total. We deeply appreciate their contributions.

In vitro incubations using natural marine communities can provide insight into community structure and function in ways that are challenging through field observations alone. We have designed a minimal metal incubation system for controlled and repeatable experimentation of microbial communities. The systems, dubbed Pelagic Ecosystem Research Incubators (PERIcosms), are 115 L, conical tanks designed to sample suspended, settled, and wall associated material for month long periods. PERIcosms combine some of the ecological advantages of large volume mesocosm incubations with the experimental ease and replication of bottle incubations, and their design is accessible for use by researchers without specialized training or travel to a designated incubation facility. Here, we provide a detailed description for the construction and implementation of PERIcosms and demonstrate their potential to promote replicable, diverse communities for several weeks under clean conditions using time-series results from two field experiments. One field experiment utilized coastal waters collected from Santa Catalina Island, CA and the other oligotrophic waters collected offshore of Honolulu, HI. Biomass metrics (chlorophyll a and particulate carbon) along with 16S/18S DNA based community composition assessments were conducted to show that communities contained within PERIcosms remained alive and diverse for several weeks using a semi-continuous culturing approach. We detail trace metal clean techniques that can be used to minimize external contamination, particularly for low dissolved iron environments. PERIcosms have the potential to facilitate natural community incubations which are needed to continue advancing our understanding of microbial ecology and geochemistry.

The Hawaii Ocean Time-series (HOT) at Station ALOHA (22.75 degrees N, 158 degrees W) in the North Pacific Subtropical Gyre (NPSG) serves as a critical vantage point for observing plankton biomass production and its ecological implications. However, the HOT program's near-monthly sampling frequency does not capture shorter time scale variability in phytoplankton populations. To address this gap, we deployed the SeaFlow flow cytometer for continuous monitoring during HOT cruises from 2014 to 2021. This approach allowed us to examine variations in the surface abundance and cell carbon content of specific phytoplankton groups: the cyanobacteria Prochlorococcus, Synechococcus, and Crocosphaera as well as a range of small eukaryotic phytoplankton (<=$$ \le $$ 5 mu m). Our data showed that daily to monthly variability in Prochlorococcus and Synechococcus abundance matches seasonal and interannual variability, while small eukaryotic phytoplankton and Crocosphaera showed the highest seasonal and interannual fluctuations. The study also found that eukaryotic phytoplankton and Crocosphaera had higher median cellular growth rates (0.076 and 0.090h-1$$ 0.090\kern0.5em {\mathrm{h}}<^>{-1} $$, respectively) compared to Prochlorococcus and Synechococcus (0.037 and 0.045h-1$$ 0.045\kern0.5em {\mathrm{h}}<^>{-1} $$, respectively). These variances in abundance and growth rates indicate that shifts in the community structure significantly impact primary productivity in the NPSG. Our results underscore the importance of daily to monthly phytoplankton dynamics in ecosystem function and carbon cycling.

Mesoscale eddies have been shown to support elevated dinitrogen (N-2) fixation rates (NFRs) and abundances of N-2-fixing microorganisms (diazotrophs), but the mechanisms underlying these observations are not well understood. We sampled two pairs of mesoscale cyclones and anticyclones in the North Pacific Subtropical Gyre in 2017 and 2018 and compared our observations with seasonal patterns from the Hawaii Ocean Time-series (HOT) program. Consistent with previous reports, we found that NFRs were anomalously high for this region (up to 3.7-fold above previous monthly HOT observations) in the centers of both sampled anticyclones. In 2017, these elevated rates coincided with high concentrations of the diazotroph Crocosphaera. We then coupled our field-based observations, together with transcriptomic analyses of nutrient stress marker genes and ecological models, to evaluate the role of biological (via estimates of growth and grazing rates) and physical controls on populations of Crocosphaera, Trichodesmium, and diatom symbionts at the mesoscale. Our results suggest that increased Crocosphaera abundances in the 2017 anticyclone resulted from the alleviation of phosphate limitation, allowing cells to grow at rates exceeding grazing losses. In contrast, distributions of larger, buoyant taxa (Trichodesmium and diatom symbionts) appeared less affected by eddy-driven biological controls. Instead, they appeared driven by physical dynamics along frontal boundaries that separate cyclonic and anticyclonic eddies. No examined controls were able to explain our 2018 findings of higher NFRs in the anticyclone. A generalized explanation of elevated NFRs in mesoscale eddies remains challenging due to the interplay of eddy-driven bottom-up, top-down, and physical control mechanisms.

Abstract. Marine diazotrophs convert dinitrogen (N2) gas into bioavailable nitrogen (N), supporting life in the global ocean. In 2012, the first version of the global oceanic diazotroph database (version 1) was published. Here, we present an updated version of the database (version 2), significantly increasing the number of in situ diazotrophic measurements from 13 565 to 55 286. Data points for N2 fixation rates, diazotrophic cell abundance, and nifH gene copy abundance have increased by 184 %, 86 %, and 809 %, respectively. Version 2 includes two new data sheets for the nifH gene copy abundance of non-cyanobacterial diazotrophs and cell-specific N2 fixation rates. The measurements of N2 fixation rates approximately follow a log-normal distribution in both version 1 and version 2. However, version 2 considerably extends both the left and right tails of the distribution. Consequently, when estimating global oceanic N2 fixation rates using the geometric means of different ocean basins, version 1 and version 2 yield similar rates (43–57 versus 45–63 Tg N yr−1; ranges based on one geometric standard error). In contrast, when using arithmetic means, version 2 suggests a significantly higher rate of 223±30 Tg N yr−1 (mean ± standard error; same hereafter) compared to version 1 (74±7 Tg N yr−1). Specifically, substantial rate increases are estimated for the South Pacific Ocean (88±23 versus 20±2 Tg N yr−1), primarily driven by measurements in the southwestern subtropics, and for the North Atlantic Ocean (40±9 versus 10±2 Tg N yr−1). Moreover, version 2 estimates the N2 fixation rate in the Indian Ocean to be 35±14 Tg N yr−1, which could not be estimated using version 1 due to limited data availability. Furthermore, a comparison of N2 fixation rates obtained through different measurement methods at the same months, locations, and depths reveals that the conventional 15N2 bubble method yields lower rates in 69 % cases compared to the new 15N2 dissolution method. This updated version of the database can facilitate future studies in marine ecology and biogeochemistry. The database is stored at the Figshare repository (https://doi.org/10.6084/m9.figshare.21677687; Shao et al., 2022).

These Simons Collaboration on Ocean Processes and Ecology (SCOPE) data products were produced by the University of Hawaiʻi at Mānoa with support from the Simons Foundation. This dataset was collected on the R/V Kilo Moana during the PARAGON 2 cruise which departed from and returned to Honolulu, HI. The cruise track was Lagrangian, following free-floating arrays deployed in a chlorophyll bloom feature. Three biooptical instruments were plumbed to the underway uncontaminated seawater (intake depth 6m). Data for each instrument were averaged to the minute and matched to a timestamp on the minute. LISST: Filtered values (<0.2 um) removed from all data. The summed volume concentration of particles (in uL/L), the standard LISST output, is presented for 3 size ranges: 1.25-2 µm, 2-20 µm, and 20-100 µm. Larger size classes are excluded due to low detection limits and scattering at density gradients. Note that data have not been processed to remove outliers. AC-S: Filtered values (<0.2 um) removed from all data (see White et al., 2017, GRL); data corrected for residual temperature and scattering; AC-S chl a concentrations obtained from a Gaussian fit over absorbance spectra in the red portion of the spectrum, assuming in vivo chl-a specific absorption of 0.0203 m2/mg at 674 nm. ECO: filtered values (<0.2 um) removed from chl and volume scattering data; chl fluorescence converted to mg/m3 using factory calibrations. CDOM not included due to faulty channel. Time is in UTC.

On behalf of the journal, AGU, and the scientific community, the editors of Geophysical Research Letters would like to sincerely thank those who reviewed manuscripts for us in 2022. The hours reading and commenting on manuscripts not only improve the manuscripts, but also increase the scientific rigor of future research in the field. With the advent of AGU's data policy, many reviewers have also helped immensely to evaluate the accessibility and availability of data, and many have provided insightful comments that helped to improve the data presentation and quality. We greatly appreciate the assistance of the reviewers in advancing open science, which is a key objective of AGU's data policy. We particularly appreciate the timely reviews in light of the demands imposed by the rapid review process at Geophysical Research Letters. We received 6,687 submissions in 2022 and 5,247 reviewers contributed to their evaluation by providing 8,720 reviews in total. We deeply appreciate their contributions in these challenging times.

This dataset was collected on the R/V Thompson during the Gradients V cruise which departed from San Diego, CA and ended in Honolulu, HI. A transect was performed on the 140 degree longitude line from roughly 16 degrees N to 4 degrees S before heading to Honolulu. Fluorometric Chlorophyll were collected from the R/V Thompson's CTD/Rosette system and filtered at low vacuum through a glass fiber filter. Samples were then frozen and stored in foil until analysis. Post cruise, the filters were extracted using 90% acetone for a total of 48 hours in a -20°C freezer, covered to prevent the photodegradation of pigments. Samples were then run on a Turner 10-AU Fluorometer. Data were corrected for average glass fiber filter blank values and when available is reported as the average of duplicate samples. Time in UTC.