The ocean is one of the planet’s most important carbon reservoirs, and the efficiency with which carbon fixed by phytoplankton is transferred from the surface to the deep sea, the so-called biological carbon pump, helps determine how much carbon dioxide the ocean can lock away on climatically relevant timescales. In vast stretches of the open ocean, chronic nutrient scarcity keeps primary production low and dominated by tiny cells such as the cyanobacterium Prochlorococcus. Under these conditions, much of the newly fixed carbon never leaves the surface layer at all. Instead, it is retained and remineralized within the microbial loop, a closed circuit in which bacteria and other heterotrophic microbes rapidly recycle organic matter back into carbon dioxide. The result is a low transfer efficiency: little carbon reaches higher trophic levels or the ocean interior.

The Gulf of Aqaba offers an ideal natural laboratory for studying how this efficiency changes with the seasons. Every winter, deep convective mixing injects nutrients from below into the surface layer, fueling phytoplankton blooms. In summer, the picture reverses. Surface waters warm to between 25 and 28 degrees Celsius, and a sharp vertical temperature gradient isolates the sunlit euphotic zone from the nutrient-rich waters below. During the 2023 study period, from May to September, the researchers measured the mixed layer shoaling from about 45 meters in early summer to just 15 to 20 meters at the height of stratification in July and August. Nutrient concentrations in the upper 100 meters were correspondingly meager: nitrate plus nitrite ranged from below detection to only 0.14 micromoles per liter, orthophosphate hovered between 0.01 and 0.03 micromoles per liter, and the ratio of nitrogen to phosphorus fell well below the canonical Redfield ratio of 16 to 1, pointing to nitrogen limitation of the microbial community.

To track where the carbon actually went, the team used radiocarbon labeling. Seawater samples collected at 20-meter intervals from the surface down to 100 meters were spiked with sodium bicarbonate labeled with carbon-14 and incubated for 24 hours under ambient temperature and light. After incubation, the samples were gently filtered through glass-fiber filters with a nominal pore size of 0.7 micrometers. The carbon-14 retained on the filters measured particulate primary production, the carbon incorporated into algal biomass, while the labeled carbon passing through the filters quantified dissolved primary production, the photosynthate released extracellularly by the cells. Bacterial production was measured separately using tritiated leucine incorporation, and community respiration was estimated from the decline in dissolved oxygen in dark 24-hour incubations monitored with fiber-optic oxygen sensors. From these measurements the team calculated the percentage of extracellular release and the bacterial growth efficiency, the fraction of consumed organic carbon that bacteria convert into their own biomass rather than respire away.

The seasonal trajectory was unambiguous. Depth-integrated particulate primary production collapsed from 1.26 grams of carbon per square meter per day in May to just 0.35 grams per square meter per day as stratification intensified, a decline of more than 70 percent. Surface rates fell from roughly 25 micrograms of carbon per liter per day to about 8. Meanwhile, the fraction of total production released as dissolved organic carbon climbed steadily: the integrated percentage of extracellular release rose from 2.5 percent in May to between 5.7 and 6.4 percent during June through August, and reached 7.4 percent by September. Near the base of the euphotic zone, below 40 to 60 meters, extracellular release in individual samples climbed as high as 20 percent. The authors attribute this to nutrient stress: when carbon fixation outpaces the assimilation of nitrogen and phosphorus, cells exude excess low-molecular-weight photosynthates, effectively leaking carbon-rich, nutrient-poor dissolved organic matter into the surrounding water.

That leaked carbon did not linger. Dissolved primary production, though modest at 0.02 to 0.03 grams of carbon per square meter per day, correlated positively with bacterial production, which ranged from 0.08 to 0.16 grams of carbon per square meter per day and was highest in mid- to late summer. This coupling suggests that freshly released dissolved substrates directly fuel heterotrophic bacteria, forming a tight conduit between algal photosynthesis and microbial consumption. A statistical analysis of all depth-resolved measurements across the five cruises reinforced the picture: dissolved production correlated significantly with bacterial production, while particulate production showed a negative correlation with chlorophyll, indicating that carbon fixation and release track physiological activity rather than standing biomass. Chlorophyll itself was concentrated in a deep chlorophyll maximum between 60 and 100 meters, which the authors interpret as a photo-acclimation maximum, cells packing more chlorophyll per unit biomass under low light, rather than a true biomass maximum.

Perhaps the most consequential finding concerns bacterial growth efficiency. Despite the decline in primary production, bacterial respiration remained substantial throughout the summer, between 0.23 and 0.52 grams of carbon per square meter per day across the upper 100 meters. As a result, bacterial growth efficiency stayed low to moderate, ranging from 13 percent in May and June to 28 to 30 percent later in the season. In other words, for every unit of organic carbon the bacteria processed, the majority was respired back into dissolved inorganic carbon rather than converted into biomass that could enter the food web or sink. The authors argue that in the hyper-oligotrophic, warm, and physically isolated summer water column, nutrient limitation forces bacteria to respire surplus carbon through overflow metabolism to satisfy their nutritional demands while covering high basal metabolic costs. This contrasts with systems such as the Taiwan Strait, where recent work has reported elevated growth efficiencies, suggesting that oligotrophy alone does not dictate bacterial metabolism; substrate quality, stoichiometry, and physical setting all matter.

The authors also addressed a potential methodological concern: because Prochlorococcus cells are smaller than the nominal 0.7-micrometer pore size of glass-fiber filters, some cells might pass through and inflate the dissolved fraction. Prior work, they note, shows that under low-vacuum filtration comparable to their protocol, roughly 95 percent of Prochlorococcus cells are retained, and chlorophyll recovery on glass-fiber filters matches that of finer 0.2-micrometer membranes in oligotrophic waters. Moreover, the seasonal rise in extracellular release tracked changes in nutrient availability and microbial physiology rather than chlorophyll biomass, supporting the interpretation that the increase reflects a genuine physiological response of nutrient-stressed algae rather than a filtration artifact.

The broader significance lies in what this seasonal snapshot implies for a warming ocean. Climate change is intensifying density stratification across low- and mid-latitude seas, and the Gulf of Aqaba’s summer regime may foreshadow conditions becoming more widespread. If stronger stratification generally shifts carbon allocation from particulate biomass toward dissolved pathways, then more of the ocean’s primary production will be recycled within the surface microbial loop rather than exported to depth, weakening the biological carbon pump and shortening the residence time of carbon in the ocean’s upper layers. The authors call for long-term observations and targeted experiments that manipulate stratification, nutrient supply, and temperature, integrated with trait-based ecosystem models, to predict how microbial communities will adjust their carbon processing as oligotrophication progresses. For now, the message from this small corner of the Red Sea is clear: as the sea warms and stratifies, the microbes that dominate its surface waters become increasingly efficient recyclers and increasingly poor couriers of carbon to the deep.

Subject of Research: Seasonal water-column stratification and microbial carbon cycling in the oligotrophic Gulf of Aqaba, northern Red Sea

Article Title: Seasonal stratification regulates carbon allocation between particulate and dissolved pathways in the Gulf of Aqaba

Article References: Rahav, E., & Paytan, A. (2026). Seasonal stratification regulates carbon allocation between particulate and dissolved pathways in the Gulf of Aqaba. Ocean Science, 22(5), 2711-2723. https://doi.org/10.5194/os-22-2711-2026

Image Credits: AI Generated

DOI: 10.5194/os-22-2711-2026

Keywords: ocean carbon cycle, biological carbon pump, Gulf of Aqaba, Red Sea, water-column stratification, primary production, dissolved organic carbon, bacterial respiration, bacterial growth efficiency, microbial loop, oligotrophic ocean, ocean warming

The study, published in PLOS Ecosystems by Emmanuel Boss, Charlotte Begouen Demeaux, and Michael J. Behrenfeld, revisits how the euphotic depth should be computed. The authors revive an argument made two decades ago by the influential biological oceanographer Karl Banse, who died in 2025: phytoplankton, the microscopic algae that anchor the marine food web, do not sense light as a percentage of surface illumination. They experience only the absolute flux of photons arriving at whatever depth they happen to occupy. A definition based on relative light levels, the authors contend, is therefore physiologically meaningless.

The one-percent rule has undeniable practical appeal. It can be estimated with an uncalibrated radiometer, a simple Secchi disk, or satellite ocean-color products, and it appears in studies of phytoplankton seasonal cycles, carbon flux calculations, and remote-sensing data distributed worldwide. But the new analysis, built on nearly 21,000 profiles from autonomous BGC-Argo floats spanning October 2012 to December 2023, shows that the absolute amount of light found at the one-percent horizon varies enormously with latitude, season, and cloud cover. At any given moment, roughly seventy percent of the ocean lies beneath clouds, and seasonal swings in solar angle halve surface irradiance by thirty degrees latitude and extinguish it entirely near the poles in winter.

Instead of a percentage, the authors recommend anchoring the euphotic depth to a fixed absolute light level called the compensation irradiance: the minimum daily light at which photosynthesis can outpace algal respiration, allowing net growth. Drawing on recent Arctic field campaigns and laboratory work, they propose a value of 0.0035 plus or minus 0.002 mol photons per square meter per day, a figure orders of magnitude lower than many earlier estimates and close to the theoretical minimum of about 0.0009 mol photons per square meter per day derived from the bioenergetics of photosynthesis.

The evidence for such extraordinarily low-light growth comes from converging sources. In Baffin Bay, researchers using chlorophyll fluorescence and particle backscattering sensors below sea ice detected the onset of phytoplankton accumulation at an average light level of 0.0043 mol photons per square meter per day. A separate Arctic study coupling biomass measurements with radiocarbon-based production assays found a compensation irradiance of 0.0035 mol photons per square meter per day, essentially identical to the value now proposed. In the Southern Ocean near the Kerguelen Islands, incubation experiments previously documented positive net primary production at the 0.01 percent light level, corresponding to roughly 0.006 mol photons per square meter per day.

Critically, the new work extends the argument beyond polar waters. Analyzing cytometric counts of Prochlorococcus, the abundant photosynthetic bacterium that dominates nutrient-poor oceans, from the Atlantic Meridional Transect cruise 13, the authors found significant cell concentrations down to depths where daily light falls to the proposed 0.0035 threshold, even in subtropical latitudes. Oxygen-based measurements of gross primary production from other Atlantic transects likewise show detectable production at the 0.1 percent light level. Because the ocean is well connected and microbial strains disperse globally, the authors reason that an algal lineage capable of near-theoretical-minimum growth in the Arctic almost certainly has counterparts elsewhere.

The quantitative consequences are striking. Across the BGC-Argo dataset, the one-percent light horizon sits, on average, about 80 meters, or 48 percent, shallower than the depth of the proposed compensation isolume. When the authors integrated chlorophyll and phytoplankton carbon from the surface down to each horizon, the conventional one-percent cutoff missed more than sixty percent of the biomass inventory captured by the deeper boundary: average integrated chlorophyll was 40.9 versus 65.3 milligrams per square meter, and phytoplankton carbon 1.1 versus 1.8 grams per square meter. A substantial reservoir of phytoplankton, in other words, lives below the depth where most studies assume production stops.

That oversight matters for the biological pump, the suite of processes that transports carbon from the surface ocean into the deep sea, where it can remain sequestered for decades to centuries. Many pump estimates treat everything below the one-percent horizon as a realm of pure respiration, assuming any phytoplankton found there will simply sink. If production actually continues deeper, those assumptions inflate the apparent strength of the pump. Similar biases arise in estimates of the mixed-layer pump, the seasonal export of carbon when springtime shallowing of the mixed layer strands biomass in darkening water; using the shallower horizon overstates how much carbon that mechanism delivers to depth.

Numerical ecosystem and biogeochemical models, notably, already sidestep the percentage convention. They instead assign phytoplankton a constant basal respiration rate, typically 0.02 to 0.03 per day, and growth occurs only where photosynthesis exceeds that cost. The authors show, through a standard photosynthesis formulation, that such respiration rates imply a compensation irradiance of roughly 0.036 mol photons per square meter per day, still an order of magnitude above the lowest field estimates. Even models, it seems, do not yet allow production at the dimmest levels where real algae demonstrably persist.

The authors acknowledge open questions. Temperature might, in principle, raise respiration and thus the required light at lower latitudes, but meta-analyses suggest the temperature dependence of algal net growth weakens and effectively vanishes as light becomes limiting, lending support to a single global threshold. Deep mixed layers and internal waves complicate the light environment individual cells experience, and the appropriate isolume for a given question may differ: migrating zooplankton follow far dimmer isolumes, while nutrient and particle-attenuation horizons align with much brighter ones. Still, the recommendation is unambiguous: after nearly a century, oceanographers should retire the one-percent rule for defining the euphotic depth and adopt a physiologically grounded, absolute light threshold, a shift the authors suggest could be implemented with existing satellite products and may ultimately revise how the living ocean is measured from top to bottom.

Subject of Research: Redefining the ocean's euphotic depth using a physiologically based compensation irradiance instead of the one-percent surface light convention

Article Title: Revisiting how the euphotic depth is computed

Article References: Revisiting how the euphotic depth is computed. (n.d.). https://doi.org/10.1371/journal.pesy.0000032

Image Credits: AI Generated

DOI: 10.1371/journal.pesy.0000032

Keywords: euphotic depth, phytoplankton, compensation irradiance, oceanography, primary production, biological pump, BGC-Argo, Prochlorococcus, light attenuation, carbon export, Arctic Ocean, marine ecosystems

The scientific problem GLAMR addresses is deceptively simple to state and remarkably hard to solve. Lake metabolism refers to the balance between the carbon a lake takes up through photosynthesis, performed by plants and algae, and the carbon it releases through respiration, the process by which living organisms break down food into energy and carbon dioxide. That balance, expressed as the difference between gross primary production and ecosystem respiration, determines whether a given lake functions as a net carbon sink or a net carbon source, how much energy flows into its food web, and whether its waters remain hospitable to the uses people depend on. As Cary aquatic ecologist Christopher Solomon, who leads the effort, explained, the processes being quantified play a huge role in determining the suitability of lakes for drinking water, recreation, and fisheries.

Why has this fundamental quantity gone unmeasured at scale? Part of the answer lies in the sheer heterogeneity of the world’s lakes. Ecosystems everywhere show distinctive seasonal rhythms of production and respiration. Temperate deciduous forests in the northeastern United States, for example, run high rates of photosynthesis through the summer, then see photosynthesis plummet and respiration dominate during the leafless, snow-covered winter months. Mediterranean forests behave differently, keeping photosynthesis above respiration throughout the year in a pattern that depends more on spring and autumn rains. These metabolic signatures are well characterized for most major ecosystem types. Lakes, ponds, and reservoirs, by contrast, have resisted the same systematic treatment, in part because their conditions can shift dramatically from day to day and from one basin to the next, and because the instruments needed to capture those shifts have only recently become widespread.

The consequence of that blind spot is more than an academic inconvenience. Without a global picture of lake metabolism, scientists cannot accurately quantify the role inland waters play in the global carbon cycle or in the Earth system more broadly, and they cannot predict how lakes will respond to global change. Lakes are known to process, transport, and store substantial amounts of carbon, and warming temperatures, altered precipitation, nutrient runoff, and shifting ice cover all have the potential to reconfigure the metabolic balance of these systems. Solomon noted that the lack of understanding limits the ability to quantify the role of lakes in the carbon cycle and to forecast their trajectories under environmental change, a limitation GLAMR is explicitly designed to remove.

Assembling the repository is an exercise in data harmonization as much as data collection. Some of the information GLAMR will incorporate already exists, but it is scattered across hundreds of published and unpublished sources, collected with different instruments, calibrated differently, and stored in incompatible formats. GLAMR will organize and harmonize these datasets, pulling together daily measurements of dissolved oxygen, water temperature, wind speed, and other variables that together allow researchers to compute metabolism at the scale of individual lakes and then compare those patterns across continents. Solomon identified the data infrastructure as the most challenging part of the project, describing the task of integrating hundreds of millions of data points published by hundreds of different researchers as a big and ambitious undertaking. He added that the team already has a strong start, thanks to earlier support from Cary Institute’s Science Innovation Funds and from Grand Valley State University.

New data will continue to flow in from collaborators around the world, many of them affiliated with the Global Lake Ecological Observatory Network, known as GLEON, an international grassroots network of scientists, students, educators, policy makers, and citizens who study and monitor lake ecosystems. High-frequency sensors deployed on buoys and moorings, such as the long-running monitoring buoy on Lake Mendota in Wisconsin, capture the fine-scale fluctuations in oxygen and temperature that underpin modern metabolism estimates, and GLEON’s distributed community of lake observers provides both the instruments and the local expertise. Cary Institute ecologist Kathleen Weathers, who co-created GLEON and serves as senior personnel on the project, described GLAMR as very much an outgrowth of that network, saying she is excited to play a role in guiding and participating in GLAMR’s extension and expansion of networked lake science.

Training the next generation of freshwater scientists is built into the project’s design. Weathers will lead a training program for GLEON graduate fellows that guides early-career researchers in conducting GLAMR-enabled research, ensuring that the repository is not merely a static archive but a living platform that cultivates new analytical approaches and new questions. Data in the repository will be published and made available to interested scientists everywhere, reflecting the project’s open-access ethos. In an era when reproducibility and data sharing are increasingly central to credible science, GLAMR’s commitment to making hundreds of millions of harmonized observations publicly available positions it as infrastructure for the entire discipline rather than the private resource of a single research group.

Once the repository is assembled, Solomon and colleagues will move from curation to synthesis. Their first analytical targets include defining the various lake metabolism archetypes, the recurring patterns of production and respiration that characterize different classes of lakes, and understanding why those archetypes differ in time and space. From there, the team aims to predict how lake metabolism might change in the future as climate warming, land use change, and other pressures continue to reshape inland waters. Such archetype-based classification could ultimately allow researchers to extrapolate from the hundreds of monitored lakes in GLAMR to the millions of lakes worldwide, turning a curated dataset into a globally predictive framework for freshwater carbon cycling and water quality.

The project’s leadership spans four institutions, each bringing complementary strengths. Christopher Solomon of the Cary Institute of Ecosystem Studies serves as lead principal investigator, joined by Isabella Oleksy of the University of Colorado Boulder, Stuart Jones of Grand Valley State University, and Paul Hanson of the University of Wisconsin-Madison, with Kathleen Weathers of Cary Institute serving as senior personnel. The combination of long-term sensor deployments, ecosystem modeling expertise, and network coordination experience mirrors the interdisciplinary character of the question itself, which sits at the intersection of ecology, biogeochemistry, limnology, and data science.

For a field that has watched its study sites warm, stratify differently, and lose ice cover year after year, the arrival of a unified global metabolism database marks a turning point. What individual researchers have observed at their own lakes, sometimes for decades, will finally become comparable, combinable, and visible at planetary scale. If GLAMR succeeds, the metabolic rhythms of the world’s lakes, ponds, and reservoirs will move from the margins of ecosystem science into the same well-mapped territory long occupied by forests, grasslands, and the ocean, giving scientists a fighting chance to understand, and anticipate, how the freshwater systems humanity depends upon will fare in a changing world.

Subject of Research: Creation of a global open-access lake metabolism database to study lake health, carbon cycling, and climate impacts

Article Title: Cary to lead $2.3 million NSF-funded effort to build global lake ecosystem database

Article References: Cary to lead $2.3 million NSF-funded effort to build global lake ecosystem database. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: lake metabolism, GLAMR, Cary Institute, National Science Foundation, carbon cycle, freshwater ecology, water quality, GLEON, dissolved oxygen, primary production, respiration, open-access database

The challenge the researchers set out to solve is one that has frustrated coastal scientists for decades. Satellites can track ocean productivity in the open sea by detecting the green pigment of phytoplankton, and these observations have transformed our understanding of global carbon cycling and marine food webs. But in shallow, murky estuaries, the algorithms fail. Suspended sediments and colored dissolved organic matter absorb and scatter light in ways that confuse the satellite signal, and in very shallow water the seafloor itself reflects and absorbs light, further muddying the picture. Yet it is precisely these shallow systems where the seafloor matters most: as water depth decreases, the biomass of benthic producers such as microalgae, turfing algae, and seagrass per unit of seabed increases, while the phytoplankton biomass in the water column above that seabed shrinks. In estuaries averaging two meters deep or less, seabed production can account for the majority of the ecosystem’s total primary productivity.

To see past the murk, the team built their model from the ground up, using empirical measurements rather than satellite data. The approach had three pillars. First, they constructed a harbor-specific seabed light model, driven by incident sunlight recorded at a weather station near Whakatane, bathymetry assembled from vessel surveys and LIDAR, and turbidity profiles collected at more than forty locations throughout the harbor. Boosted regression tree models, trained on 1,243 paired measurements of light penetration, depth, and turbidity, predicted the percentage of surface light reaching every ten-by-ten-meter grid cell of the harbor at two-hourly intervals across an entire year, with a mean deviance explained of 0.94. Second, they mapped the distribution of the three dominant seabed habitats: seagrass, sand, and mud. Third, they linked light to life through habitat-specific photosynthesis-irradiance curves derived from aquatic eddy covariance deployments, an instrument technique that measures oxygen exchange between the seafloor and overlying water continuously, at high frequency, over multiple day-night cycles.

Those photosynthesis-irradiance curves revealed striking differences among habitats. Seagrass reached a maximum photosynthetic rate of 183 millimoles of oxygen per square meter per day, five and a half times higher than mud at 33.1 and more than double that of sand at 88.1. But seagrass also consumed oxygen fastest at night, at 72.3 millimoles per square meter per day, compared with 47.6 for sand and 28.6 for mud. Each habitat switched from net oxygen consumption to net production at a different light threshold, known as the compensating irradiance point: mud required the least light, at 23.8 micromoles of photons per square meter per second, sand needed 34.6, and seagrass needed 69.3. These curves, combined with the habitat map and the light model, allowed the researchers to compute net oxygen flux for every grid cell, every two hours, for a full year from June 2020 to May 2021.

The resulting maps are visually arresting. Patches of intertidal seagrass blaze bright green as hotspots of production, while the deeper subtidal channels appear in dark hues even where the sediment type is identical to shallower areas nearby, because light attenuates with depth. When the daily values were averaged across the whole harbor, a clear seasonal rhythm emerged. Winter, from June to August, was the low point, with productivity of 44.7 plus or minus 8.9 millimoles per square meter per day, significantly lower than the other three seasons. Spring averaged 55.9, autumn 53.1, and summer 51.5, none significantly different from one another. The single lowest day fell on June 25, 2020, at 16.7 millimoles per square meter per day, and the highest on September 9, 2020, at 65.1. July was the weakest month overall, averaging 38.6, significantly below every other month.

Perhaps the most remarkable finding is that Ōhiwa Harbour remained net autotrophic—producing more oxygen than it consumed—on every single day of the year, even in the depths of winter when turbidity was highest and sunlight weakest. Monthly average productivity never dropped below 38 millimoles per square meter per day. The researchers attribute this resilience to the harbor’s extreme shallowness: 79 percent of it is intertidal, and the high productivity of shallow seafloor relative to deep water kept the system in the black. Seagrass, despite covering only three percent of the seascape, punched far above its weight, contributing two to five times the productivity of other habitats under high light. The team notes that even though their seagrass curve was built from data collected outside Ōhiwa and in a single season, the harbor-wide patterns are relatively robust to inaccuracies in that curve because seagrass occupies such a small fraction of the domain.

The implications reach well beyond one New Zealand estuary. Estuaries are widely described as among the most productive habitats on Earth, yet whole-estuary productivity dynamics have rarely been mapped, leaving a gap in our ability to protect areas of high ecosystem functioning—a strategic goal of the Kunming-Montreal Global Biodiversity Framework. The stakes are rising. Climate change is expected to increase sediment loads to estuaries through more frequent and intense storms, while sea level rise deepens shallow systems, and together these forces are “darkening” estuarine seabeds, cutting the light that fuels benthic production. Meanwhile, the historical reclamation of shallow intertidal habitats near coastal cities has likely reduced the oxygen-producing capacity of those systems, potentially contributing to the hypoxic zones that have accumulated exponentially worldwide since the 1950s, with consequences ranging from altered biogeochemistry to fish kills and shellfish die-offs.

The study also carries a cultural dimension. The researchers worked alongside Ngāti Awa, the Indigenous Māori guardians of Ōhiwa Harbour, whose restoration efforts recently led to the return of dense beds of green-lipped mussels near the harbor entrance. Māori conceptualize waterways as living beings whose vitality, or mauri, depends on the health of all their parts, much like the organs of a body. The pulsed daily, tidal, and seasonal rhythms of productivity the model revealed resonate directly with this worldview: the seafloor as a breathing lung whose maintenance sustains the whole. The mussel beds themselves illustrate a subtlety of valuation—a dense mussel bed is likely a net oxygen sink because of its enormous animal biomass, yet it delivers food, water purification, and food web support, showing that low seabed production does not mean low value.

The authors are candid about limitations. The model is heuristic rather than strictly predictive: seagrass distribution was a single snapshot in time, sand and mud were treated as homogeneous, intertidal production was assumed to match submerged production at maximum irradiance, and only a quarter of the eddy covariance deployments occurred within Ōhiwa itself, in winter only. With updated habitat layers, the framework could become far more accurate. Even so, the team has provided something coastal managers have lacked: a transferable tool, with code publicly available on Figshare, that can predict estuary primary productivity under different scenarios of climate change, sea level rise, sediment loading, and habitat loss. Local actions—fencing stock from riparian edges, afforesting catchments, ending logging on steep slopes—cannot stop the sea from rising, but they can keep the estuary’s lungs working, sustaining the shellfish, fish, biodiversity, and nutrient removal services that depend on them.

Subject of Research: Mapping seasonal and daily dynamics of seafloor primary production in a shallow New Zealand estuary

Article Title: The breathing seascape: Spatial and temporal up-scaling of an estuarine ecosystem function

Article References: Lohrer, A. M., Stephenson, F., Lam-Gordillo, O., MacDonald, I. T., Massuger, J., Paul-Burke, K., Douglas, E. J., Petersen, G. L., & Bulmer, R. H. (2026). The breathing seascape: Spatial and temporal up-scaling of an estuarine ecosystem function. iScience, 29(10), Article 117597. https://doi.org/10.1016/j.isci.2026.117597

Image Credits: AI Generated

DOI: 10.1016/j.isci.2026.117597

Keywords: estuary, primary production, seagrass, benthic ecosystems, aquatic eddy covariance, Ōhiwa Harbour, New Zealand, ocean darkening, ecosystem services, hypoxia, Māori stewardship, coastal management