Among marine organisms, gelatinous zooplankton (GZ; cnidarians, ctenophores, and pelagic tunicates) are unique in their energetic efficiency, as the gelatinous body plan allows them to process and assimilate high proportions of oceanic carbon. Upon death, their body shape facilitates rapid sinking through the water column, resulting in carcass depositions on the seafloor (“jelly‐falls”). GZ are thought

The export of particulate organic carbon (POC) from surface waters to the ocean interior via the biological carbon pump is largely envisioned as a vertical process. However, several lines of evidence suggest that lateral supply of aged organic matter hosted on lithogenic particles derived from sediment resuspension may also be a significant process. Despite its potential importance, lateral POC supply

Biological nitrogen fixation is increasingly recognized as an important source of new nitrogen in a warming ocean. However, the basin‐scale spatiotemporal distribution of nitrogen‐fixing organisms (diazotrophs) in the ocean and its controlling environmental factors remain unclear. Here we examined the basin‐scale seasonal distribution patterns of major diazotrophs (filamentous cyanobacterial Trichodesmium

Vegetation fires play an important role in global and regional carbon cycles. Due to climate warming and land use shifts, fire patterns are changing and fire impacts increasing in many of the world's regions. Reducing uncertainties in carbon budgeting calculations from fires is therefore fundamental to advance our current understanding and forecasting capabilities. Here we study 20 chamber burns from

Primary productivity of forest ecosystems depends on the availability of plant‐essential mineral nutrients. Because nutrient demand of trees often exceeds nutrient supply from rock, tree nutrition is sustained by efficient reutilization of organic‐bound nutrients. These nutrients are continuously returned from trees to the forest floor in litterfall. However, over millennia nutrient limitation may

Glacial fjords in Greenland show high productivity owing to the runoff of meltwater from the glaciers. Macronutrient dynamics (of nitrate, phosphate, and silicate) associated with subglacial discharge plumes in front of marine‐terminating glaciers are widely cited as important drivers of summer phytoplankton blooms in the fjords. However, the dynamics of iron (Fe), an essential micronutrient for primary

The Southern Ocean is an important region of ocean carbon uptake, and observations indicate its air‐sea carbon flux fluctuates from seasonal to decadal timescales. Carbon fluxes at regional scales remain highly uncertain due to sparse observation and intrinsic complexity of the biogeochemical processes. The objective of this study is to better understand the mechanisms influencing variability of carbon

Reactive nitrogen (N) fluxes have increased tenfold over the last century, driven by increases in population, shifting diets, and increased use of commercial N fertilizers. Runoff of excess N from intensively managed landscapes threatens drinking water quality and disrupts aquatic ecosystems. Excess N is also a major source of greenhouse gas emissions from agricultural soils. While N emissions from

The magnitude of future emissions of greenhouse gases from the northern permafrost region depends crucially on the mineralization of soil organic carbon (SOC) that has accumulated over millennia in these perennially frozen soils. Many recent studies have used radiocarbon (14C) to quantify the release of this “old” SOC as CO2 or CH4 to the atmosphere or as dissolved and particulate organic carbon (DOC

Although iron availability has been shown to limit ocean productivity and influence marine carbon cycling, the rates of processes driving iron's removal and retention in the upper ocean are poorly constrained. Using 234Th‐ and sediment‐trap data, most of which were collected through international GEOTRACES efforts, we perform an unprecedented observation‐based assessment of iron export from and residence

Soils in the Amazon Basin are deficient in phosphorus, essential to soil fertility. Previous studies suggested that African mineral dust deposited to Amazonian soils served as an important source of phosphorus that enhances soil fertility. These studies lacked the quantitative measurements essential to validate estimates. Here we present daily measurements of mineral dust and PM10 carried in the trade

One of the primary sources of micronutrients to the sea surface in remote ocean regions is the deposition of atmospheric dust. Geographic patterns in biogeochemical processes such as primary production and nitrogen fixation that require micronutrients like iron (Fe) are modulated in part by the spatial distribution of dust supply. Global models of dust deposition rates are poorly calibrated in the

Sedimentary nitrogen isotope (as δ15N) records from the Southern Ocean provide critical constraints on surface nutrient consumption in the past and the role of Southern Ocean biophysical changes in setting atmospheric pCO2. We present a field assessment of how surface nitrate consumption is reflected in δ15N values of total nitrogen and diatom‐bound nitrogen pools of particles and sediments across

The continuous growth of atmospheric nitrous oxide (N2O) is of concern for its potential role in global warming and future stratospheric ozone destruction. Climate feedbacks that enhance N2O emissions in response to global warming are not well understood, and past records of N2O from ice cores are not sufficiently well resolved to examine the underlying climate‐N2O feedbacks on societally relevant

Tropical forests account for a large portion of the Earth's terrestrial carbon pool. However, rapid deforestation threatens the stability of this carbon. We examine radiocarbon (Δ14C) and stable carbon (δ13C) isotopes of soil organic matter to provide insight into rates of carbon turnover, inputs, and losses of pasture‐derived (C4) versus forest or oil palm‐derived (C3) carbon. Data are presented for

The negative feedback between chemical weathering and climate is hypothesized to act as an important control on modulating atmospheric CO2 over geologic timescales, affecting the evolution of Earth's climate over the history of Earth. Here, we investigated solute production processes by analyzing concentration‐discharge, denoted here as concentration‐runoff (C‐q), relationships of Chinese monsoonal

The burial of “blue carbon” in coastal marsh soils is partially offset by marsh–atmosphere methane (CH4) fluxes, but this offset may be greater if other pathways of CH4 export exist. Here we report that salt marshes also export dissolved CH4 via submarine groundwater discharge (SGD). The volumetric fluxes of salt marsh groundwater into adjacent tidal creeks were calculated from mass balances of the

The ocean's ability to take up and store CO2 is a key factor for understanding past and future climate variability. However, qualitative and quantitative understanding of surface‐to‐interior pathways, and how the ocean circulation affects the CO2 uptake, is limited. Consequently, how changes in ocean circulation may influence carbon uptake and storage and therefore the future climate remains ambiguous

We investigated basin‐wide distributions of total particulate phosphorus (TPP) and associated biogeochemical parameters in the euphotic zone (EZ) of the subtropical North and South Pacific Ocean. TPP is primarily composed of living microorganisms, and its distribution is likely controlled by nitrogen (N) supply in typical N‐limited Pacific waters as well as phosphorus (P) supply in P‐limited western

The distribution of dissolved silicon isotopes (δ30Si) was examined along the U.S. GEOTRACES East Pacific Zonal Transect (GP16) extending from Peru to Tahiti (10°S and 15°S latitude). Surface waters in the subtropical gyre displayed high δ30Si due to strong utilization of silicic acid (DSi). In contrast, surface waters close to the Peruvian coast where upwelling prevailed were less depleted and only

No abstract is available for this article.

Anthropogenically forced changes in ocean biogeochemistry are underway and critical for the ocean carbon sink and marine habitat. Detecting such changes in ocean biogeochemistry will require quantification of the magnitude of the change (anthropogenic signal) and the natural variability inherent to the climate system (noise). Here we use Large Ensemble (LE) experiments from four Earth system models

It is well established that the ocean is currently losing dissolved oxygen (O2) in response to ocean warming, but the long‐term, equilibrium response of O2 to a warmer climate is neither well quantified nor understood. Here we use idealized multimillennial global warming simulations with a comprehensive Earth system model to show that the equilibrium response in ocean O2 differs fundamentally from

Chemical weathering of volcanic rocks in warm and humid climates contributes disproportionately to global solute fluxes. Geochemical signatures of solutes and solids formed during this process can help quantify and reconstruct weathering intensity in the past. Here, we measured silicon (Si) and germanium (Ge) isotope ratios of the soils, clays, and fluids from a tropical lowland rainforest in Costa

Boreal forests store 30% of the world's terrestrial carbon (C). Consequently, climate change mediated alterations in the boreal forest fire regime can have a significant impact on the global C budget. Here we synthesize the effects of forest fires on the stocks and recovery rates of C in boreal forests using 368 plots from 16 long‐term (≥100 year) fire chronosequences distributed throughout the boreal

Identifying ocean acidification and its controlling mechanisms is an important priority within the broader question of understanding how sustained anthropogenic CO2 emissions are harming the health of the ocean. Through extensive analysis of observational data products for ocean inorganic carbon, here we quantify the rate at which acidification is proceeding in the western tropical Pacific Warm Pool

Coastal wetlands are among the most productive habitats on Earth and sequester globally significant amounts of atmospheric carbon (C). Extreme rates of soil C accumulation are widely assumed to reflect efficient C storage. Yet the fraction of wetland C lost via hydrologic export has not been directly quantified, since comprehensive budgets including direct estimates of lateral C loss are lacking. We

Uranium isotopes (238U/235U) have been used widely over the last decade as a global proxy for marine redox conditions. The largest isotopic fractionations in the system occur during U reduction, removal, and burial. Applying this basic framework, global U isotope mass balance models have been used to predict the extent of ocean floor anoxia during key intervals throughout Earth's history. However,

We examine the role of sea ice in controlling air‐sea carbon fluxes around Antarctica using numerical simulations and idealized theory. Upwelling of carbon and nutrient‐rich deep waters in the Southern Ocean promotes outgassing of CO2 and fuels the biological flux of sinking organic particles. Sea ice inhibits outgassing, by presenting a physical barrier to air‐sea exchange (capping), and decreases

Continental margins are hot spots for iron (Fe) and manganese (Mn) cycling. In the Arctic Ocean, these depositional systems are experiencing rapid changes that could significantly impact biogeochemical cycling. In this study, we investigate whether continental margin sediments north of Svalbard represent a source or sink of Fe and Mn to the water column and how climate change might alter these biogeochemical

Soil organic carbon (SOC) is the most critical component of global carbon cycle in grassland ecosystems. There has been growing interest in understanding SOC dynamics and driving forces of grassland biomes at various temporal and spatial scales. Up to now, estimates of long‐term and large‐scale changes in SOC of grassland biomes have been mostly based on modelling approaches and manipulative experiments

Planktonic ecosystems are usually modeled in terms of autotrophic and heterotrophic compartments. However, the trophic strategy of unicellular organisms can take a range of mixotrophic strategies with both autotrophic and heterotrophic contributions. The dominant emerging strategy found in nature depends on the environment (both biotic and abiotic aspects) and the cell size and influences key ecosystem

Pyrogenic organic residues from wildfires and anthropogenic combustion are ubiquitous in the environment and susceptible to leaching from soils into rivers, where they are known as dissolved black carbon (DBC). Here we quantified and isotopically characterized DBC from the second largest river on Earth, the Congo, using 12 samples collected across three annual hydrographs from 2010 to 2012. We find

Land use changes exert important impacts on climate, primarily through altering greenhouse gas (GHG) and surface energy fluxes. Biogeochemical models have incorporated a relatively complete suite of biogeochemical processes to simulate GHG fluxes. However, these models often lack detailed processes of surface energy exchange, limiting their ability to assess the impacts of land use change on climate

The origin and reactivity of dissolved organic matter (DOM) have received attention for decades due to the key role DOM plays in global carbon cycling and the ecology of aquatic systems. However, DOM dynamics in river networks remain unresolved, hampered by the lack of data integrating the spatial and temporal dimensions inherent to riverine ecosystems. Here we examine the longitudinal patterns of

Members of the editorial board of Global Biochemical Cycles express their appreciation to those who served as peer reviewers for the journal in its inaugural year.

No abstract is available for this article.

Peat soils drained for agriculture and forestry are important sources of carbon dioxide and nitrous oxide. Rewetting effectively reduces these emissions. However, rewetting also increases methane emissions from the soil and, on forestry‐drained peatlands, decreases the carbon storage of trees. To analyze the effect of peatland rewetting on the climate, we built radiative forcing scenarios for tropical

We estimated the distribution of CH4 emissions and sinks from wetlands (including freshwater and coastal wetlands) and nonwetland (including wet and dry soils) with a newly developed vertically resolved soil CH4 model, integrated into a global land surface model (ISAM). We calibrated and tested this integrated model with CH4 observations at test sites in the Contiguous United States (CONUS). ISAM is

Though it is clear that the North Atlantic is the site of the highest storage of anthropogenic carbon (C a n t ) per area, it is uncertain whether the air‐sea C a n t  fluxes contributing to North Atlantic C a n t  storage occur in the subpolar gyre or upstream in the subtropical gyre. Using data and models, we show that air‐sea C a n t  uptake capacity is advected into the subpolar gyre along the

An ocean iodine cycling model is presented, which predicts upper ocean iodine speciation. The model comprises a three‐layer advective and diffusive ocean circulation model of the upper ocean, and an iodine cycling model embedded within this circulation. The two primary reservoirs of iodine are represented, iodide and iodate. Iodate is reduced to iodide in the mixed layer in association with primary

Net primary production (NPP) fueled by nitrate is often equated with carbon export, providing a metric for CO2 removal to the deep ocean. This “new production paradigm” assumes that nitrification, the oxidation of regenerated ammonium to nitrate, is negligible in the sunlit upper ocean. While surface layer nitrification has been measured in other oceanic regions, very few data exist for the Southern

Daily in situ rates of gross production and community respiration estimated from high frequency diel cycles in oxygen (O2) and optically derived particulate carbon from several platforms (both ship‐based and via profiling floats) were made across an ecological gradient in the North Pacific spanning the high nutrient/low chlorophyll subarctic to the oligotrophic subtropical gyre. Both oxygen and carbon‐based

No abstract is available for this article.

While phytoplankton play a key role in ocean biogeochemical cycles, the availability and supply pathways of resources that support their growth remain poorly constrained. Here, we show that the availability of various resources varies over several orders of magnitude throughout the Atlantic Ocean, causing regional contrasts in resource deficiency. Regional variations in the relative availability of

Amplification of the ocean carbon sink during El Niño events partially offset terrestrial biosphere carbon losses to the atmosphere, but uncertainties in the magnitude, timing, and spatial extent of the ocean response confound our understanding of the global carbon budget and its sensitivity to climate. Here, we examine the mechanisms controlling the anomalous tropical Pacific Ocean CO2 drawdown during

A photochemical model was used to quantify the global relative contribution of carbonyl photoproduction in the photodegradation of marine dissolved organic carbon (DOC). As model input, wavelength‐ and temperature‐dependent apparent quantum yields (AQY) for the photochemical production of carbonyl compounds were determined in seawater collected from the Northwest Atlantic Ocean. These AQY data and

The potential of carbonyl sulfide (COS) flux measurements as an additional constraint for estimating the gross primary production (GPP) depends, among other preconditions, on our understanding of the soil COS exchange and its contribution to the overall net ecosystem COS flux. We conducted soil chamber measurements of COS, with transparent chambers, in three different ecosystems across Europe. The

No abstract is available for this article.

Nutrients, such as nitrogen and phosphorus, provide vital support for human life, but overloading nutrients to the Earth system leads to environmental concerns, such as water and air pollution on local scales and climate change on the global scale. With an urgent need to feed the world's growing population and the growing concern over nutrient pollution and climate change, sustainable nutrient management

Soil organic carbon (SOC) information is fundamental for improving global carbon cycle modeling efforts, but discrepancies exist from country‐to‐global scales. We predicted the spatial distribution of SOC stocks (topsoil; 0–30 cm) and quantified modeling uncertainty across Mexico and the conterminous United States (CONUS). We used a multisource SOC dataset (>10 000 pedons, between 1991 and 2010) coupled

Although subglacial aquatic environments are widespread beneath the Antarctic ice sheet, subglacial biogeochemistry is not well understood, and the contribution of subglacial water to coastal ocean carbon and nutrient cycling remains poorly constrained. The Whillans Subglacial Lake (SLW) ecosystem is upstream from West Antarctica's Gould‐Siple Coast ~800 m beneath the surface of the Whillans Ice Stream

Biological nitrogen fixation is a key contributor to sustaining the terrestrial carbon cycle, providing nitrogen input that plants require. However, the amount and global distribution of this fixation is highly disputed. Using a comprehensive meta‐analysis of field measurements, we make a new assessment of global biological nitrogen fixation (BNF). We assessed the relationship between BNF in natural

Silicon (Si) exports from terrestrial to marine systems can dictate phytoplankton species composition in Arctic coastal waters. Diatoms are often the dominant autotroph in Arctic waters, making Si an important control on Arctic marine primary productivity. Yet even as Arctic regions are among the fastest warming on Earth, we lack baseline knowledge on the magnitudes and controls of Arctic river Si

Siliceous polycystines and phaeodarians are open‐ocean planktonic protists found throughout the water column and characterized by complex siliceous skeletons that are formed, at least partly, through the uptake of silicic acid. These protists contribute to the marine organic carbon (C) and biogenic silica (bSi) pools, but little is known about their contribution to the silica (Si) biogeochemical cycle

Iron can be a growth‐limiting nutrient for phytoplankton, modifying rates of net primary production, nitrogen fixation, and carbon export ‐ highlighting the importance of new iron inputs from the atmosphere. The bioavailable iron fraction depends on the emission source and the dissolution during transport. The impacts of anthropogenic combustion and land use change on emissions from industrial, domestic

The characteristics of soils in part determine human‐induced land use and land cover (LULC) change, and together, soil properties and LULC directly impact global water, energy, and biogeochemical cycles. Plant health and the exchange of energy, water, and biogeochemical components at the surface interface are partly controlled by soil properties. Different soil types modify vegetation responses to

An interdisciplinary approach is needed for understanding tree physiology and forest biogeochemical cycles undergoing climate change and rising atmospheric CO2. We combined tree ring time series, wood isotope signatures, remotely sensed variables, and climatic data to perform a spatiotemporal scaling analysis of tree physiology and high‐elevation forest responses to rising CO2. The main question addressed

Multiple aquatic ecosystems (pond, lake, river, lagoon, and ocean) on the Arctic Coastal Plain near Utqiaġvik, Alaska, USA, were visited to determine their relative atmospheric CO2 flux and how this may have changed over time. The nearshore coastal waters and large freshwater lakes were small sinks of atmospheric CO2, whereas smaller waterbodies were substantial sources. pCO2 was linked to dissolved

Dark carbon fixation (DCF) by chemoautotrophic microorganisms can sustain food webs in the seafloor by local production of organic matter independent of photosynthesis. The process has received considerable attention in deep sea systems, such as hydrothermal vents, but the regulation, depth distribution, and global importance of coastal sedimentary DCF have not been systematically investigated. Here