Manure amendments are widely used in agriculture to enhance crop productivity and maintain soil organic matter, but they also contribute to greenhouse gas emissions and reactive nitrogen (N) losses. Manure acidification and nitrification inhibitors (NIs) have been proposed as mitigation strategies, but their effectiveness likely varies with soil characteristics. To evaluate the influence of acidified and NI‐treated manure on N cycling across different soil types, we conducted a 28‐day laboratory incubation using soils collected from major agricultural regions in Wisconsin. We measured emissions of nitrous oxide (N 2 O), nitric oxide (NO), carbon dioxide (CO 2 ), and methane (CH 4 ), along with soil ammonium (NH 4 + ) and nitrate (NO 3 − ) dynamics. Acidified manure enhanced short‐term NH 4 + retention in all soils but increased cumulative N 2 O emissions in the sandy soil compared to untreated manure, likely due to pH‐driven disruption of nitrification and incomplete denitrification. In contrast, the NI dicyandiamide (DCD) consistently suppressed nitrification early in the incubation, resulting in significantly lower N 2 O and NO emissions, often approaching levels observed in the no‐manure controls, particularly in the sandy soil. Manure amendments increased CO 2 fluxes relative to the no‐manure controls, but acidified manure emitted less CO 2 than DCD‐treated manure, likely due to temporary suppression of microbial respiration. CH 4 emissions were minimal and largely unaffected by treatments. NIs offer consistent benefits in reducing N 2 O and NO losses, while acidification can increase these emissions in certain soil conditions, highlighting the importance of tailoring management practices to specific soil characteristics.

Soil is the largest active terrestrial carbon reservoir. However, modeling soil carbon decomposition across diverse environments remains challenging, as most models use uniform, predefined parameter values within the same biome or soil type. Here, using a continental-scale incubation dataset of 156 soil samples from 20 National Ecological Observatory Network sites and a mechanistic model, we quantified decomposition parameters—decay rate (K) and carbon use efficiency (CUE)—for particulate and mineral-associated organic carbon across the US. Notably, K and CUE exhibited a 10-fold variation across soils, influenced by well-recognized (pH and nitrogen) and underrepresented geochemical and microbial factors (e.g., oxalate-extractable iron, fungal abundance). By integrating key predictors, we generated gridded maps of K and CUE, unveiling different spatial decomposability patterns of particulate and mineral-associated organic carbon across the contiguous US. Our findings underscore the need to incorporate underrepresented edaphic factors into models to improve spatially heterogeneous carbon decomposition estimations.

Coastal wetlands are vital global carbon reservoirs, yet the mechanisms governing the accrual and persistence of organic carbon (OC) remain unresolved. Through a continental-scale survey of China's coastal wetlands (including saltmarshes and mangroves) combined with a global data synthesis, we demonstrated that coastal wetlands were overwhelmingly dominated by mineral-associated OC (MAOC), which constituted similar to 73% of total OC-significantly more than in forests and peatlands. This MAOC showed no evidence of mineral saturation, underscoring its potential as an important repository for additional carbon storage. The OC content of the high-density (>1.6 g cm(-3)) and fine-grained (silt + clay, <53 mu m) soil fraction (g C kg(-1) fraction), termed the dense/fine fraction, was driven by primary productivity, pH, and mineral specific surface area. Contrary to the prevailing assumption that both silt and clay promote MAOC, increasing silt content decreased specific surface area and diluted the OC content of the dense/fine fraction, while higher clay content provided greater surface area that enhanced OC accrual. MAOC persistence, measured by Delta C-14, was primarily predicted by OC content of the dense/fine fraction, outweighing the influence of mineral attributes. Mean annual temperature was the second strongest predictor of MAOC persistence, with warmer climate leading to a larger but faster-cycling MAOC pool, highlighting a climatological temperature-driven trade-off between its accumulation and vulnerability. Saltmarshes-with lower MAOC content yet greater persistence and more abundant high-reactivity phyllosilicates than mangroves-may represent ideal targets for boosting carbon storage through increased OC inputs. Our findings establish the dominance and persistence of mineral-associated carbon in coastal wetlands and underscore their potential for targeted efforts to accrue and store carbon.

Abstract Reactive nitrogen (Nr) gases (NH3, N2O, and NO) emitted from agricultural fields constitute a substantial portion of the Nr flux from land to the atmosphere. Here, we coupled the Flows of Agricultural Nitrogen (FANv3) with a modified version of the Community Land Model (CLM5.1) to produce a model (CLM‐FANv3) that simulates the emissions of NH3, NO, and N2O. CLM‐FANv3 is developed under the strong observational constraints of measurements conducted in mesocosms from a US Corn‐Belt agricultural site where corn is planted subject to different fertilizer amounts and soil types. Combining measurements and models allows us to integrate disparate measurements of the mesocosm to produce more complete insights into the dynamic flow of nitrogen within the soil system. The new nitrogen dynamics in CLM‐FANv3, as constrained by the measurements, are different than CLM5.1 with much‐enhanced nitrification (2.5×), enhanced uptake of nitrate in plants (5×), increased nitrate leaching (an order of magnitude larger), and decreased denitrification (about half) at the mesocosm site. NH3 emissions are comparable to denitrification to N2, a significant term neglected in most Earth System Models. The emission factors for NO and N2O in CLM‐FANv3 (0.8%, 1.9%) are in reasonable agreement with the measured emission factor (1.7%, 1.4%), a substantial improvement over the CLM5.1 coupled with FANv2 model (0.2%, 3.5%). The strong measurement constraints have important implications for simulating expected future changes in Nr emissions. Differences in nitrogen cycling also impact projected amounts of carbon stored in agricultural soils over the long term.

Ponds are significant emitters of greenhouse gases (GHGs). While eutrophication stimulates GHG emissions, responses to nutrient pulses and weather events are less clear. We investigated both immediate and cumulative effects of experimental storm-scale nutrient pulses, along with unplanned extreme heat and wind events during the experiment, on GHG fluxes in nutrient-enriched ponds compared to reference ponds. Physical disturbances had greater immediate effects on GHG fluxes than did nutrient pulses due to effects on stratification and oxygen. Extreme heat increased CO2 flux and methanogenesis potential, while extreme wind increased CO2 flux. The combination of nutrients and extreme heat, however, triggered physicochemical changes that stimulated GHG emissions, doubling CH4 efflux from nutrient-enriched ponds prior to late-summer mixing. Late-summer emissions from reference ponds closed the gap in cumulative CH4 and CO2 efflux between treatments; however, suggesting that storm-driven nutrient loading may not increase total within-season GHG emissions from shallow aquatic systems.

Biological nitrogen fixation (BNF) supplies much of soybean (Glycine max (L.) Merr.) nitrogen (N) demand, but reported fixation rates vary widely, leading to uncertainty in the soybean N cycle. We quantified whole-plant soybean BNF and N allocation using long-term 15N labeling to assess whether BNF can offset grain N removal in a high-yielding system, and to quantify root contributions to fixed N. Field mesocosms in Iowa, USA received three legacy fertilizer N rates as 2 atom

Nitrogen (N) fertilizer supports global food production, but its use and overuse drive emissions of nitrous oxide (N _2 O), a potent and long-lived greenhouse gas. Understanding the drivers of N _2 O fluxes remains elusive, making it difficult to predict emissions in time and space and to develop and evaluate ways to lower emissions through management. Major scientific uncertainties underlying the understanding of the drivers of N _2 O fluxes identified in a workshop of N _2 O emissions experts include poor process-based understanding of controls on soil N _2 O emissions in the field; insufficient data to reduce uncertainty in N _2 O budgets from the field to regional scales, including N _2 O emission measurements and importantly, field-scale N balances; and high uncertainty in model predictions of soil N _2 O emissions across environmental and management conditions. To reduce these uncertainties, we present the concept of N _2 Onet, a global collaborative initiative to accelerate advances in N _2 O measurement, analyses, and mitigation. N _2 Onet will serve as an observational network of supersites with multi-scale measurements; a database hub for N _2 O flux and ancillary data; and a catalyst for community building, information sharing, and training. By coalescing and coordinating the global community of researchers, N _2 Onet will provide a roadmap for reducing N _2 O emissions from agriculture worldwide.

Soil organic carbon (SOC) comprises particulate (POC) and mineral-associated organic carbon (MAOC), which differ in formation, stabilization, and loss mechanisms. While the current global distribution of POC and MAOC is characterized, their vulnerability under future climate scenarios remains unclear. Using 3284 topsoil (0-30 cm) observations from six continents, we identify high-latitude soils as global hotspots of SOC vulnerability under shared socioeconomic pathway scenarios (SSP126, SSP245, and SSP585). Under a high-emission scenario (SSP585), high-latitude soils are projected to lose substantial POC by 2100, accounting for about 81 ± 10% of total SOC losses. These declines are driven by the high proportion of SOC stored as POC (fPOC) and its high temperature sensitivity. We show that fPOC is a robust indicator of SOC vulnerability to climate change. Globally, the projected POC decline corresponds to a cumulative carbon dioxide (CO2) release of 81.34 Pg CO2-equivalent by 2100, highlighting the importance of preserving POC to mitigate climate feedbacks.

Individual fungi and bacteria can decompose lignin, but little is known about how specific taxa and their interactions may be related to this critical carbon-cycling process across diverse environments. We characterized relationships between bacterial and fungal communities and mineralization of isotope-labeled lignin across 156 incubated mineral soil samples collected from 20 National Ecological Observatory Network sites spanning diverse ecosystems (tundra to tropics) across North America. Based on marker gene sequencing, bacteria were more closely related to lignin mineralization than fungi at the levels of overall community composition, individual taxa, and co-occurrence network. We identified 14 bacterial and fungal genera across sites and 26 taxa (mostly bacteria) within sites, including two genera (Occallatibacter and Terracidiphilus) that were significantly related to lignin mineralization within and across sites. Additionally, many microbial ‘modules’ from co-occurrence networks were related to lignin mineralization, and this was even more evident during the later stages of decomposition. This suggests the importance of microbial interactions for lignin decay and implies that microbes interacted in a way favoring lignin decomposition over the incubation. We identified 10 bacterial-fungal interactions (BFI) that could significantly strengthen and 10 BFI that could weaken microbial relationships with lignin mineralization, indicating that synergistic and antagonistic BFI were both important. Overall, our study illustrated the key importance of microbial interactions even more so than individual taxa for predicting lignin mineralization.

ABSTRACTNutrient inputs influence the sustainability of bioenergy crop production through contemporary (shortly after addition) and legacy effects (persisting over years) on microbial nitrogen (N) and carbon cycling, which contribute to greenhouse gas emissions. However, the relative importance of contemporary and legacy effects and how that could vary by crop functional types is poorly understood. Considering its rhizomatous roots and perennial growth, we hypothesized that Miscanthus × giganteus (M×g) would be more sensitive to legacy N fertilization and the historical context of its environment than an annual crop like maize. To test this hypothesis, we examined the effects of legacy and contemporary N inputs on nitrous oxide (N2O) and carbon dioxide (CO2) emissions, as well as key N cycling genes in soils where M×g and maize were grown. A 150‐day soil incubation experiment was conducted using soils from a long‐term M×g and maize fertility experiment with three historic N fertilization rates (0, 112, and 336 kg N ha−1 year−1) and a contemporary amendment (60 mg N kg−1) with negative control (0 mg N kg−1). We observed significant increases in cumulative N2O emissions in Mxg soils relative to maize soils, particularly at higher legacy fertilization rates, while contemporary N had no significant effect. Bacterial amoA gene abundance, which plays a significant role in nitrification in nutrient‐rich soils, also increased with higher legacy fertilization rates in M×g soils but was unaffected by the contemporary N. In maize soils, legacy and contemporary N did not significantly affect N2O emissions, but cumulative CO2 emissions and amoA gene abundance significantly increased. The abundances of norB genes were not significantly influenced by either legacy fertilization or contemporary N amendments in either soil. Our findings demonstrate the greater importance of fertilization history over contemporary N in mediating soil N2O emissions, particularly for perennial bioenergy crops.

Conservation drainage practices can mitigate water quality impacts of subsurface drainage, but their potential for climate change mitigation remains poorly understood. We summarized processes by which tile-drained croplands impact climate and assessed potential of conservation drainage practices to alter emissions of the greenhouse gases nitrous oxide (N2O) and methane (CH4) and stocks of soil organic carbon (SOC), compared using carbon dioxide equivalents (CO2e). Controlled drainage, bioreactors, saturated buffers, and water quality wetlands can decrease nitrate leaching with little or no increase in on-site N2O emissions, thereby decreasing indirect N2O emissions that would otherwise occur from downstream waters. However, under some conditions, CH4 emissions from bioreactors and especially from wetlands can counteract climate benefits of decreased indirect N2O emissions. Drainage water recycling could potentially increase direct soil N2O emissions while decreasing indirect N2O emissions, but these impacts might be mitigated through sub-irrigation and increased drainage intensity. Many conservation drainage practices are unlikely to markedly increase SOC, aside from saturated buffers. Expressed relative to the area of cropland treated by a given practice, saturated buffers may have the largest climate mitigation potential of examined practices due to the combination of efficient nitrate removal with low N2O emissions, lower risk of CH4 emissions, and high potential for SOC accrual. In sum, available data suggest that several conservation drainage practices can plausibly contribute to climate change mitigation as well as water quality improvement, although more comprehensive studies are needed to better constrain their effectiveness.

Soil organic carbon (SOC) decomposition underpins soil-atmosphere carbon exchange and is regulated by climate change-mediated variations in soil redox conditions. Periodic anoxia, commonly occurring following precipitation, soil flooding, and erosion events, is assumed to preserve SOC. Yet, water saturation may also increase SOC decomposition relative to unsaturated conditions, and contradictory findings among previous studies remain unexplained. Here, using incubation experiments on 20 soils collected across a 24° latitude gradient in China, we show that 70% of the soils showed a higher or similar anoxic decomposition rate of SOC compared to the oxic treatment, indicating fast SOC loss under relatively short anoxia. Methane production was far lower than CO2 due to the presence of alternative terminal electron acceptors (TEAs). Variation in alternative TEAs and microbial community shows that fast anoxic decomposition was primarily driven by iron (Fe) reduction, which accounted for up to 90% of anoxic CO2 production. Meanwhile, positive relationships among water-extractable organic carbon (OC), hydrochloric acid-extractable ferrous Fe, relative abundance of Fe-reducing prokaryotes, and the SOC decomposition rate suggest the release of readily metabolized substrates following Fe reduction. This release provided substrates for anoxic metabolism and potentially led to the loss of OC protected by Fe (Fe-bound OC; a slow-cycling OC pool under oxic conditions). Mass balance calculation confirms that Fe-bound OC loss was mostly similar to elevated anoxic SOC decomposition in magnitude, and random forest modeling indicates that soils rich in reducible Fe, SOC, and Fe-reducing prokaryotes most likely experience elevated SOC decomposition under periodic anoxia. Overall, our findings demonstrate that fast anoxic decomposition of SOC is a potentially important pathway that may stimulate SOC loss under climate change-mediated intense hydrologic regimes, particularly for soils rich in reducible Fe and SOC.

Anaerobic digestion can produce renewable natural gas and is a viable alternative to conventional sources. When anaerobic digesters are coupled with agricultural systems, the resulting anaerobic digestate solids (ADS) after biogas production can be applied to fields as a fertilizer and an organic soil amendment. Therefore, ADS can potentially increase soil organic carbon (SOC) stock and improve soil fertility. To better understand the impacts of ADS on SOC accumulation and nutrient release, we conducted a 120‐day laboratory incubation using four ADS rates (0, 2.5, 5, and 10 Mg C ha −1 ) in typical loamy and sandy soils of Iowa. We measured respired CO 2 ‐C, δ 13 CO 2 ‐C, dissolved reactive phosphorus (DRP), and extractable nitrogen (N). ADS‐derived CO 2 increased, but SOC‐derived CO 2 decreased as the ADS rate increased, indicating a negative priming effect (average of −78%). The C balance in the soil, defined as C inputs minus C respiration, significantly increased with ADS rates. Using reasonable bulk density and mixing depth assumptions, applying the medium ADS rate to soil would accumulate more SOC in the sandy than in the loamy soil (3 vs. 2.2 Mg C ha −1 ). Extractable N and DRP release rates were affected by ADS rates but in opposite directions. DRP increased while extractable N decreased with ADS additions. We conclude that ADS is a bioavailable source of C and nutrients for soil microbes that decreases short‐term inorganic N, increases phosphorus availability, and leads to SOC accrual.

Soil methane (CH4) emissions significantly impact climate change. However, microbial controls of CH4 in global carbon cycle gain less attention than CO2, hindering the understanding of CH4 processes. Here, stemming from a baseline model (MENDmm1) with one microbial group, we developed a microbial-explicit CH4 model by representing six microbial groups following Michaelis-Menten kinetics (MENDmm6). We compared MENDmm6 with MENDfo6 (first-order kinetics) and MENDmm5 (excluding syntrophic acetate oxidation, SAO), alongside MENDmm1. Split-sample calibration and validation were conducted using high-temporal-resolution CO2 and CH4 effluxes from two soils (Oxisol and Mollisol) under five oxygen-fluctuation treatments. MENDmm6 (mean R2 = 0.66) improved CH4 modeling by 47 % over MENDmm1 (mean R2 = 0.45), with a 15 % improvement for CO2. MENDmm6-simulated methanogenic and methanotrophic biomass closely matched observed OTU abundances (r = 0.69-0.94), except for methanotrophs in the Oxisol (r = 0.13). Furthermore, including microbial processes without explicit microbial kinetics (MENDfo6) did not improve model performance over MENDmm1. Neglecting SAO in MENDmm5 failed to explain the observed hydrogenotrophic methanogenesis dominance. Our results emphasize the significance of explicit microbial communities and kinetics in CH4 modeling. The proposed MENDmm6 model, leveraging molecular measurements of CH4-cycling microbes, will enhance predictions of management impacts on CH4 emissions, crucial for climate mitigation.

Anaerobic ammonium oxidation coupled with iron (Fe) reduction, known as Feammox, is an important nitrogen (N)-cycling pathway in anoxic soils. Biochar, widely employed as a soil amendment, has been reported to influence N dynamics through its redox-active moieties, but the effects on Feammox of biochar produced with different pyrolysis temperatures remain poorly understood. We conducted a slurry incubation in rice-paddy soil with N-15-isotope tracing to examine the impact of biochar pyrolyzed at 300 degrees C and 600 degrees C on Feammox under different Fe availability conditions (addition of ferrihydrite, goethite, or no Fe). Biochar pyrolysis temperature and Fe availability impacted rates of Feammox. Specifically, adding biochar pyrolyzed at 600 degrees C to soil at a 2 % mass ratio stimulated N loss through Feammox by 0.03 to 0.07 mu g N g(-1) soil d(-1), likely by facilitating electron transfer via its surface redox-active moieties. Feammox was highly correlated with Fe reduction despite contributing only a small fraction to overall Fe reduction. Feammox rates were greatest with ferrihydrite addition and lowest with no Fe addition, and correlated with the abundance of a known Feammox bacterium (Acid-imicrobiaceae bacterium A6). In contrast, biochar pyrolyzed at 300 degrees C did not stimulate Feammox, likely due to a lack of electron shuttling capacity. Overall, our findings highlight a stimulation effect of biochar pyrolyzed at high temperature on promoting N loss as dinitrogen, underscoring its potential utility for environmentally-friendly removal of excess N from anoxic soil.

An important control on long-term soil organic carbon (SOC) storage is the adsorption of SOC by short-range-ordered (SRO) minerals. SRO are commonly quantified by measuring oxalate-extractable metals (Mox = Alox + ½ Feox), which many studies have shown to be positively correlated with SOC. It remains uncertain if this organo-mineral relationship is robust at the global scale, or if capturing regional differences is needed to maximize model accuracy. We used a global synthesis of Alox and Feox data to test their role in controlling SOC abundance across regions. We compiled 37,344 individual soil horizon measurements, with soil depth ranging between 0 and 200 cm, from 11,122 profiles. We used the Holdridge Life Zones, which are characterized by biotemperature, precipitation, and potential evapotranspiration, to group the soil profiles by their climatic conditions that also correlate with other important soil-forming factors. Based on linear mixed-effects models, we found a positive relationship between Mox and SOC across regions and depths, accounting for 49

Diversified cropping systems offer a chance to mitigate environmental impacts of conventional agriculture, but effects on soil organic carbon (SOC) sequestration and nitrogen (N) dynamics remain debated. We integrated a 20-year field experiment and laboratory measurements with three stable-isotope-enabled mechanistic models to examine SOC stocks and decomposition in a conventional corn–soybean system and two more diversified systems including small grains, legumes and manure inputs, in addition to corn and soybean. Contrary to the prevalent hypothesis that diversified systems increase SOC, we found no differences in 0.3 m topsoil or 1 m profile SOC and N stocks. Diversified systems markedly increased N mineralization rates and decomposition of older SOC from previous corn inputs. Models revealed that increased C decomposition with residence times of months to years counteracted higher C inputs but increased N supply. Our findings highlight a critical trade-off between C storage and N supply in these diversified systems, demonstrating that key climate benefits may arise from decreased N fertilizer use, not SOC sequestration. Sustainable and regenerative agriculture often employs diverse systems of crop rotation to reduce environmental impacts and sequester carbon. A long-term field study, however, reveals a trade-off between soil organic carbon storage and nitrogen supply.

Coastal wetlands are important land–ocean interfaces for organic carbon storage. It was assumed that reactive poorly crystalline or short-range-ordered iron minerals enhance organic carbon accrual and persistence. However, these metastable minerals are prone to rapid reductive dissolution, raising uncertainties about their abundance and impact on carbon cycling in coastal wetlands, where anoxia typically prevails. Here we combine a global database of 23,000 observations and a national survey across China’s coastline. We show that coastal wetlands are enriched preferentially in poorly crystalline or short-range-ordered iron minerals over well-crystalline phases, compared with uplands. Mössbauer spectroscopy reveals that ferrihydrite, nanogoethite and highly disordered phases dominated the iron oxide pool in coastal wetlands, with minor crystalline forms, challenging the notion that reactive metastable minerals are removed preferentially under anoxic conditions. We find that reactive metastable iron was most abundant in tropical wetlands, in contrast with tropical uplands where crystalline minerals predominate. Despite a higher abundance of metastable iron minerals, coastal wetlands had a similar fraction of total organic carbon associated with iron oxides ( 13

Wet tropical forests play an important role in the global carbon (C) cycle, but given current rates of land-use change, nitrogen (N) and phosphorus (P) limitation could reduce productivity in regenerating forests in this biome. Whereas the strong controls of climate and parent material over forest recovery are well known, the influence of vegetation can be difficult to determine. We addressed species-specific differences in plant traits and their relationships to ecosystem properties and processes, relevant to N and P supply to regenerating vegetation in experimental plantations in a single site in lowland wet forest in Costa Rica. Single-tree species were planted in a randomized block design, such that climate, soil (an Oxisol), and land-use history were similar for all species. In years 15-25 of the experiment, we measured traits regarding N and P acquisition and use in four native, broad-leaved, evergreen tree species, including differential effects on soil pH, in conjunction with biomass and soil stocks and fluxes of N and P. Carbon biomass stocks increased significantly with increasing soil pH (p = 0.0184, previously reported) as did biomass P stocks (p = 0.0011). Despite large soil N pools, biomass P stocks were weakly dependent on traits associated with N acquisition and use (N2 fixation and leaf C:N, p < 0.09). Mass-balance budgets indicated that soil organic matter (SOM) could supply the N and P accumulated in biomass via the process of SOM mineralization. Secondary soil P pools were weakly correlated with biomass C and P stocks (R = 0.47, p = 0.08) and were large enough to have supplied sufficient P in these rapidly growing plantations, suggesting that alteration of soil pH provided a mechanism for liberation of soil P occluded in organo-mineral soil complexes and thus supply P for plant uptake. These results highlight the importance of considering species' effect on soil pH for restoration projects in highly weathered soils. This study demonstrates mechanisms by which individual species can alter P availability, and thus productivity and C cycling in regenerating humid tropical forests, and the importance of including traits into global models of element cycling.

Aquaculture, commonly conceived as "fish farming," includes the culture of animals, plants, or other species in water. Although about 70% of Earth's surface is covered by water, aquaculture often uses much smaller spaces such as tanks, ponds, raceways, or aquatic enclosures to grow aquatic food, fiber, and other resources. Theologically, humans are called to "protect and serve" (Gen. 2:15), and throughout the Bible, there are calls to good stewardship and cultivation while allowing for fruitfulness of other creatures. Biblically, fish are seen as God-created aquatic creatures, often used as food, with implications for wise stewardship (e.g., Psalm 8). *At the present, many fisheries around the world are overfished. Sustainable aquaculture should address environmental, economic, and health concerns, and it could help reduce the stress on natural fisheries. As the fastest-growing protein sector, aquaculture now produces more seafood than the wild harvest of all the world’s oceans (now approximately 120 million metric tons per year). This promising and expanding field (approximately 6–8% growth per year over the last 50 years) includes extremely efficient converters of protein, micro- and macro-algae (seaweeds) that can absorb unwanted wastes and clean the water, and filter feeders such as oysters and clams that clear the water of algae and other particles, simultaneously contributing various ecosystem services and habitat. Ongoing problems include pathogenic and related disease issues, environmental pollution in surface waters, food safety, increasing automation utilization, potential genetic concerns, and the relatively recent start of modern aquaculture (most aquaculture growth has occurred since 1970). This article addresses each of these hurdles, identifies areas of theological and ethical concern, and clarifies matters of interest to Christians and others, suggesting possible ways forward in this fast-growing but challenging field.