Coastal agriculture has been adopted to increase agricultural productivity, whereas its effects on blue carbon ecosystem function and greenhouse gas (GHG) exchange dynamics are unclear. This research examined the impact of tidal saltwater irrigation on agronomic traits, CO2 uptake, and CH4 and N2O emissions within a coastal rice ecosystem (tidal-influenced and saline), and explored the microbial mechanisms responsible for GHGs mitigation. The study was conducted over 2 years on Chongming island, Shanghai, China. Here, the use of 6 parts per thousand saltwater for irrigation in sea rice cultivation led to an increase in net ecosystem CO2 exchange and gross primary productivity, mitigated CH4 and N2O emissions through tidal saltwater treatment with a projected decrease in CH4 emissions during the tillering stage, and was accompanied by a marked upregulation of the AcsB gene associated with CO2 fixation as well as the PmoA and Nirk2 genes involved in CH4 and N2O oxidation. Despite a decrease in plant height, this approach promoted tillering, thereby increasing shoot dry mass and ultimately maintaining rice yields without reduction. The study further revealed the combined CO2-equivalent emissions of CO2, CH4, and N2O during the tidal saltwater irrigation period, with reductions ranging from 22 % to 39 % for two different sea rice varieties. Therefore, the experimental simulation of tidal saltwater in a coastal rice system demonstrated its ability to sustain yield, increase carbon uptake and mitigate GHG emissions, although the effects were not statistically significant. We suggest that coastal rice cultivation using natural tidal irrigation is an effective approach to strengthen the ecological of coastal tidal mudflats by reducing GHG emissions and enhancing rice yields.

Salt marshes hold substantial potential for nature-based climate solutions; yet their carbon sequestration potential is threatened by greenhouse gas (GHG) emissions under global warming and sea-level rise (SLR). The combined effects of temperature and salinity on soil GHG emissions still remain unclear. This study integrated in situ monitoring and laboratory-controlled incubation to quantify the fluxes of CO2, CH4, and N2O from the salt marsh (Phragmites australis) soils in the Yangtze River Estuary, in response to temperature and salinity variations. The results demonstrated that warming magnified the influence of salinity, elevating the salinity threshold for GHG emissions, while at low temperatures (<20 degrees C), emissions remained unaffected by salinity. At low salinity (0-4 ppt), temperature significantly stimulated emissions, whereas higher salinity suppressed them. Nevertheless, at elevated salinity, soil respiration becomes more temperature-sensitive, indicating heightened microbial activity under favorable thermal conditions. Soil temperature was identified by the random forest model as the dominant control on GHG emissions than salinity, with 25 degrees C and 5 ppt identified as tipping points for temperature and salinity. Under SLR scenarios of 0.5, 1, and 2 m, GHG fluxes from the Yangtze River Estuary wetlands exhibited a slight decline in emissions with moderate salinity increases, but emissions intensify under more extreme SLR scenarios. This study underscores the combined impact of global warming, SLR, and saltwater intrusion on coastal GHG emissions, highlighting the potential reduction in the effectiveness of carbon sequestration by salt marshes. The findings offer valuable insights for evaluating future blue carbon dynamics under global change.

Understanding the lateral exchange of particulate organic matter (POM) between wetlands and estuaries is essential for understanding coastal carbon budgets and dynamics. We studied tidal and seasonal changes in the concentration of POM ([POC]) and its optical properties in three marsh creek systems along a salinity gradient in one of the world's largest river deltas - the Yangtze River Delta. Results reveal strong variability, with tides and among sites, in both [POC] and compositions of POM. The maximum tidal POC export occurred in fall with brackish marshes exporting [POC] rich (9 times higher) with a lower chromophoric signal (i.e., lower light-absorbing capacity) compared to the freshwater marsh (avg. [POC] of 1708 (brackish) and 192 (freshwater) μmol L-1; avg. normalized POM absorption a∗(350)p of 4.3 (brackish) and 16 (freshwater) L mol-1 cm-1). Creek POM in the brackish marshes were dominated by materials having visible fluorescence (avg. proportion of 54 %), likely due to a higher contribution from suspended solids and wind-induced soil erosion. Contrary, in the freshwater marsh the tidal POM was consistently enriched in materials strongly fluorescing in the UVA range (avg. proportion of 84 %), likely caused by extreme droughts and higher aboveground biomass. The primary driver of the observed differences among the three marshes were differences in hydrodynamics, with the resulting high spatial heterogeneity complicating delta-wide assessments of carbon flows and stocks. This study highlights the importance of [POC] in carbon budgets and the necessities of integrating site-specific lateral POC monitoring to improve estimates on carbon budgets in large deltas.

The rapid expansion of exotic Spartina alterniflora has significantly threatened native coastal ecosystems' structure and function, prompting global control efforts. Consequently, native saltmarshes restoration has emerged as a nature‐based solution following invasive species removal. However, given that S. alterniflora is a high‐carbon invasive species, the impacts of native saltmarshes restoration on coastal blue carbon benefits following its removal remain uncertain. Here, we quantified atmospheric carbon uptake and organic carbon storage among restored native saltmarshes ( Phragmites australis and Bolboschoenoplectus mariqueter communities), unrestored bare mudflat following S. alterniflora removal and uncontrolled S. alterniflora communities to assess whether native saltmarshes can compensate for the carbon sinks and the climate effects after invasive species eradication. The results showed that S. alterniflora removal drastically reduced carbon sink, with unrestored mudflat transitioning to a carbon source. While restored native saltmarshes showed lower atmospheric carbon uptake compared to pre‐eradication S. alterniflora levels, they exhibited significantly enhanced carbon sequestration relative to unrestored mudflats. Additionally, the organic carbon density of soil (0–50 cm) and vegetation in restored sites exceeded unrestored areas by >1.4 times, recovering >70% of the carbon storage observed in S. alterniflora communities. Sustained global warming potentials (SGWP) analysis over a 100‐year timescale revealed that without post‐eradication vegetation restoration, saltmarsh could shift from climate cooling to warming effects. Native saltmarsh restoration effectively mitigated this transition, demonstrating substantial climate change mitigation potential. Synthesis and applications . Our findings not only reveal that native saltmarsh restoration is a blue carbon‐friendly ecological restoration approach following S. alterniflora removal, but also highlight the critical trade‐offs between carbon losses from invasive species removal and the carbon offset achieved through restoring native vegetation, providing actionable guidance for coastal management. These insights are particularly valuable for regions facing similar invasive species challenges, informing the development of integrated strategies that maximize carbon compensation while enhancing coastal sustainability and climate resilience. Future restoration programmes should prioritise multifunctional outcomes that simultaneously address biodiversity conservation and climate mitigation objectives.

The overwhelming dispersion of exotic species Spartina alterniflora threatened the structure and function in native coastal ecosystems. Consequently, native saltmarshes restoration has emerged as a nature-based solution following the removal of invasive species. However, given S. alterniflora as a high carbon sequestration species, it remains uncertain on the impacts of native saltmarshes restoration on coastal blue carbon benefits following its eradication. Here, this study quantified atmospheric carbon uptake and organic carbon storage in restored saltmarsh to assess whether native saltmarsh (Phragmites australis and Bolboschoenoplectus mariqueter) restoration can compensate for the carbon sinks and the climate effects following S. alterniflora eradication. The results showed that removal of S. alterniflora drastically reduced atmospheric carbon uptake, with unrestored bare mudflat turning into carbon sources. After restored native saltmarsh, the atmospheric carbon uptake remained lower than pre-eradication levels of S. alterniflora but provided significant greater carbon sink benefits compared to unrestored bare mudflat. Additionally, the total organic carbon density of soil and vegetation at 50 cm depth in restored native saltmarsh (P. australis and B. mariqueter) exceeded that of unrestored bare mudflat by over 1.4 times, restoring over 70% that observed before eliminating S. alterniflora. Considering the sustained global warming potentials (SGWP) of CH4 over the 100-year timescale, both restored native saltmarsh communities exhibited a net cooling effect for mitigating climate warming, compared to invasive S. alterniflora community and unrestored bare mudflat after S. alterniflora removal. Our findings not only reveal that saltmarsh restoration provides a substantial route to mitigating climate change, but also highlight the trade-off between the carbon losses from eliminating invasive species and the carbon offset achieved through restoring native vegetation in affected ecosystems. This study provides actionable insights for regions confronting analogous challenges with invasive species and restoration scenarios, enabling the development of more comprehensive strategies to ensure effective carbon compensation. Future restoration efforts in invaded ecosystems should prioritize co-benefits such as conserving native ecosystems and enhancing carbon sequestration.

Salinity is a well-known environmental factor that profoundly influences vegetation growth and ecological functions of coastal salt marshes. This study conducted an in-situ control experiment to assess the effects of salinity on the morphological and physiological traits of coastal Phragmites australis, as well as its carbon sequestration capacity (including CO2 uptake, CH4 emissions, and vegetation and soil organic carbon densities). Field investigations and microbial abundance analyses were integrated to provide a comprehensive assessment. The results showed that the growth characteristics and photosynthetic activity of P. australis increased initially but declined as salinity rose, peaking at a moderate level (5 parts per thousand). Despite concurrent peaks in CO2 uptake and CH4 emissions at 5 parts per thousand salinity, the net negative daytime CO2-eq flux indicated that this salinity level provided the strongest net cooling effect, driven by stronger CO2 uptake relative to CH4-induced warming. Under higher salinity levels (> 10 parts per thousand), P. australis exhibited an adaptive strategy of reduced carbon allocation to roots, leading to a significant decrease in soil organic carbon density. Through the identification of salinity thresholds that optimize growth and carbon sequestration of P. australis, this study delivers a mechanistic understanding for advancing adaptive management and restoration efforts of coastal salt marsh ecosystems to enhance their blue carbon sequestration, particularly in the context of sea-level rise.

Spatial quantification of blue carbon ecosystem stocks is crucial for developing policies to mitigate climate change, especially in regions experiencing ongoing wetland disturbance from biological invasions. We integrated multiple machine learning models with the space-for-time substitution method to quantify the spatiotemporal impact of Spartina alterniflora invasion on tidal marsh sediment blue carbon (soil organic carbon - 'SOC') stocks at 100 cm depth in the Yangtze Estuary. Our results show that the invasive S. alterniflora contributed more than half of the total SOC stocks (2,056 +/- 379 Gg C, 1 Gg = 106 6 kg) in the 27,600 ha tidal marshes of the Yangtze Estuary, which were estimated to be 1,107 +/- 176 Gg C. S. alterniflora increased the SOC stocks in the Yangtze Estuary within the first 15 years, but this gain was not sustained in the long term, with a gradual decline (by 13.14 Mg C/ha) observed after 15 years of S. alterniflora growth. We found that sediment salinity, tidal range, and human accessibility were strong indicators for modeling and predicting SOC stocks, with Random Forest providing the best simulation of tidal marsh SOC stocks (R2 2 = 0.894, RMSE=7.646 =7.646 Mg C/ha, and MAPE=9.469 =9.469 %). Our study provides much needed information on blue carbon stocks in the Yangtze Estuary under biological invasion stress, and offers guidance for targeted S. alterniflora management actions in the future.

Climate change provides an opportunity for the northward expansion of mangroves, and thus, the afforestation of mangroves at higher latitude areas presents an achievable way for coastal restoration, especially where invasive species S. alterniflora needs to be clipped. However, it is unclear whether replacing S. alterniflora with northward-afforested mangroves would benefit carbon sequestration. In the study, we examined the key CO2 and CH4 exchange processes in a young (3 yr) northward -afforested wetland dominated by K. obovata. We also collected soil cores from various ages (3, 15, 30, and 60 years) to analyze the carbon storage characteristics of mangrove stands using a space -for -time substitution approach. Our findings revealed that the young northward mangroves exhibited obvious seasonal variations in net ecosystem CO2 exchange (NEE) and functioned as a moderate carbon sink, with an average annual NEE of -107.9 g C m(-2) yr(-1). Additionally, the CH4 emissions from the northward mangroves were lower in comparison to natural mangroves, with the primary source being the soil. Furthermore, when comparing the vertical distribution of soil carbon, it became evident that both S. alterniflora and mangroves contributed to organic carbon accumulation in the upper soil layers. Our study also identified a clear correlation that the biomass and carbon stocks of mangroves increased logarithmically with age (R-2 = 0.69, p < 0.001). Notably, both vegetation and soil carbon stocks (especially in the deeper layers) of the 15 yr northward mangroves, were markedly higher than those of S. alterniflora. This suggests that replacing S. alterniflora with northward -afforested mangroves is an effective long-term strategy for future coasts to enhance blue carbon sequestration.

土壤呼吸(soil respiration,Rsoil)是生态系统向大气释放二氧化碳(carbon dioxide,CO2)的主要碳源,其微小变化对红树林湿地碳汇有重要影响.本文以 2021年原位实时监测的每月浙南人工红树林湿地Rsoil及其环境因子数据为基础,探究了Rsoil的季节变化特征及其对生态系统呼吸(ecosystem respiration,Reco)的贡献,并分析了Rsoil对浙南人工红树林生态系统固碳能力的影响.结果表明:(1)浙南人工红树林湿地Rsoil具有明显的季节变化,在夏季达到峰值;Rsoil关键环境驱动因子为土壤温度(soil temperature,TS)和土壤湿度(soil humidity,WS),二者的综合作用可以解释 84.6%的Rsoil变化;(2)尽管 Rsoil是浙南红树林 Reco的主要贡献者,但年平均 Rsoil[(0.69±0.54)μmol/(m2·s)]低于其他滨海湿地;(3)Rsoil随林龄增大而上升,然而其增长幅度远小于净生态系统CO2 交换量(net ecosystem CO2 exchange,NEE)的增长幅度,表明浙南引种人工红树林有利于滨海湿地固碳增汇.研究结果有利于深入认识浙南人工红树林Rsoil变化特征及规律,进而为准确评估浙南红树林碳收支及其碳中和潜力提供数据支撑和理论依据.

Climate change has become one of the severe challenges faced by all countries. Carbon neutralization, through "carbon emission reduction" and "carbon sink increase", is a key way to address global climate change. Coastal blue carbon ecosystems, such as mangroves, salt marshes and seagrass beds, are huge and long-term sustainable carbon sinks. Therefore, protecting and restoring coastal ecosystems is one of the operable ways to increase carbon sinks. This paper explored the carbon pool and economic value of typical coastal blue carbon ecosystems in China. Two restored wetlands（Niyu mangrove and Yingwuzhou salt marsh）as examples are used to prove that increasing blue carbon by coastal ecosystems restoration is an effective way to realize carbon neutralization. The research results can provide theoretical basis and data support for coastal ecosystem restoration and the blue carbon trading, and further serve carbon neutralization.

Ecosystem ecologist who made fundamental contributions to carbon cycle science and advocated for the next generation of scientists

Coastal wetlands play an important role in nitrogen removal and are a vital blue carbon sink. The produced methane (CH4) in coastal wetlands has been recently identified as a possible carbon source for denitrification process, providing a significant contribution to coastal nitrogen cycling. However, the in-situ correlation between CH4 emissions and denitrification rate, as well as their coupling mechanism is still unclear. Here, we investigated the nitrogen removal pattern throughout a complete tidal cycle, quantified the in-situ linkage between CH4 emissions and denitrification rate, and explored the associated microbial mechanisms in the eutrophic coastal wetland. The results showed that (1) the removal of nitrogen was driven by the tidal cycle (marsh flooding and drying), which involved two processes - physical interception and microbial denitrification; (2) the denitrification rate was linearly positively correlated to the CH4 emission (R2 = 0.87, p < 0.0001); (3) nitrite- and nitrate-dependent denitrifying anaerobic methane oxidation (DAMO) coexisted in the wetland sediment, and promoted nitrogen removal by utilizing CH4 as the carbon source for denitrification. Our findings suggested that CH4 emission could enhance denitrification via DAMO in the field, and deepened the understanding of the dynamic nitrogen removal process within eutrophic coastal wetlands, and further indicated a strong interaction between coastal carbon and nitrogen cycling.

探讨了浙江南部人工红树林秋茄叶片光合作用与叶绿素荧光动态变化特征,以此为该物种近期北移引种生态恢复应用提供科学依据.利用LI-6800F便携式光合-荧光自动测量系统,测量了不同月份秋茄叶片光合作用、叶绿素荧光的日变化,并分析了它们之间的关系.结果表明:除了水利用效率、非光化学淬灭以外,各参数的日变化曲线大体上呈U型或倒U型,如蒸腾速率、气孔导度、电子传递速率、最大光化学反应量子效率;且夏季7月、8月部分参数值明显高于11月、12月,如净光合速率、蒸腾速率、气孔导度、电子传递速率.此外,单日上,除水利用效率分别与实际光化学量子效率、光化学淬灭系数、非光化学淬灭系数的相关性不显著外,光合因子与荧光因子的相关性显著,而各月上,仅净光合速率、蒸腾速率、气孔导度、水利用效率、电子传递速率之间的相关性显著.以上说明,单日上,中午前后是秋茄叶片光合能力最强的时候,而各月上,夏季是秋茄光合能力最强的季节,春季与秋季次之,冬季最弱;秋茄叶片光合与叶绿素荧光在单日上的相关性比在各月上的更高.

针对我国南方红壤(江西鹰潭孙家坝小流域)4种不同土地利用类型,在2019年6—10月开展了室内土壤温湿度控制实验,采用温室气体分析仪(Picarro-G2508)结合静态箱法对土壤温室气体(CO2、CH4、N2O)排放通量进行同步实时监测,以研究全球气候变化背景下不同土地利用类型土壤温室气体排放差异及其对温湿度的响应.结果显示,4种土地利用类型土壤的全球增温潜势(global warming potential,GWP)从高到低依次为稻田、橘园、林地、旱地,表明稻田土壤温室气体排放对全球变暖贡献最大.温控实验中,土壤呼吸(CO2排放)与土壤温度呈显著正指数相关关系(p<0.01),且4种土地利用类型土壤呼吸的温度敏感系数Q10值分别为林地2.61、旱地2.51、橘园3.12、稻田3.17.其中,稻田土壤呼吸的温度敏感度最高,表明稻田土壤具有较高的CO2排放潜力,而CH4、N2O排放与土壤温度的相关性不显著.湿度控制实验中,土壤CO2排放随土壤湿度增加而先升高后降低,并在土壤湿度20％GWC(gravity water content)时达到最大;稻田土壤CH4排放与土壤湿度正相关(R2=0.8875),但其他3种土地利用类型土壤CH4排放与土壤湿度不相关;4种土地利用类型土壤N2O排放通量均随土壤湿度的增加呈先增后减趋势,并在土壤湿度为25％GWC时达到峰值.

为了探究新恢复湿地对近岸水体的深度净化与水生态功能提升效果,于2017年8月—2019年4月对鹦鹉洲生态湿地各生态单元进出水水质进行监测,并分析了湿地内各个组块对污染物去除的贡献.结果显示,鹦鹉洲生态湿地对来水中NH4+-N、N02--N和N03--N的平均去除率分别为49.2％、46.3％和52.9％,对溶解性无机磷(DIP)和TP的平均去除率分别为53％和55％,对SS的平均去除率为59.6％;湿地不同区块的协同作用可以实现对多种污染物的有效去除,有效提升了水体透明度,深度净化了水质.

Wetlands play an important role in reducing global warming potential in response to global climate change. Unfortunately, due to the effects of human disturbance and natural erosion, wetlands are facing global extinction. It is essential to implement engineering measures to restore damaged wetlands. However, the carbon sink capacity of restored wetlands is unclear. We examined the seasonal change of greenhouse gas emissions in both restored wetland and natural wetland and then evaluated the carbon sequestration capacity of the restored wetland. We found that (1) the carbon sink capacity of the restored wetland showed clear daily and seasonal change, which was affected by light intensity, air temperature, and vegetation growth, and (2) the annual daytime (8–18 hr) sustained‐flux global warming potential was −11.23 ± 4.34 kg CO2 m−2 y−1, representing a much larger carbon sink than natural wetland (−5.04 ± 3.73 kg CO2 m−2 y−1) from April to December. In addition, the results showed that appropriate tidal flow management may help to reduce CH4 emission in wetland restoration. Thus, we proposed that the restored coastal wetland, via effective engineering measures, reliably acted as a large net carbon sink and has the potential to help mitigate climate change.

In this study, we reported a practice at northern Hangzhou Bay, southeast China aimed at restoring coastal wetlands within the intertidal zone outside of the seawalls. The principle idea is protecting the site and helping the marsh establishment by engineering measures, and thereafter, relieving the protections to encourage the self-organization of the restored ecosystem. The results of this implementation showed the marsh reached an average vegetation cover of 70% in the first year. The excess nitrogen was removed by an ecological recirculating treatment system, which was coupled in the wetland. The long-term performance of the wetland suggested that it could resist disturbances such as hurricanes and algal blooms, and provided clean water habitat for aquatic fauna. By presenting the case of Hangzhou Bay, we call for more novel coastal restoration implementations that aim to create new boundaries with engineering features and self-organization, which benefit both human and nature.

To improve the ecosystem services of wetlands in response to global climate change, wetland restoration projects have become prevalent worldwide. Restored wetlands have the potential to remove external nitrogen through denitrification, but incomplete denitrification may increase nitrous oxide (N2O) release. In order to comprehensively understand nitrogen removal and N2O emission processes in restored wetlands, we conducted carbon (anhydrous sodium acetate) and nitrogen (sodium nitrate) addition experiments in the Fengxian coastal wetland site. These experiments explored the roles of external nitrogen, carbon sources, and wetland plants in nitrogen removal and N2O emission. With the addition of nitrogen, the removal of external nitrogen was significant at the restored wetland site, but led to increasing N2O release. However, by adding carbon sources, the restored wetland could not only enhance nitrogen removal efficiency through denitrification, but also significantly reduce N2O emission. Our results demonstrate that carbon availability could improve the ecological functions of coastal restored wetlands by improving water quality and mitigating greenhouse gas emissions.

When solar-induced chlorophyll fluorescence (SIF) is developed as a novel approach to quantify gross primary production (GPP), narrow SIF emission spectrum around the atmospheric oxygen absorption windows ((similar to) 761 nm and (similar to)687 nm) has been widely used to represent SIF and to derive GPP. As SIF is a continuous spectrum, deriving the full broadband SIF emission spectrum over 640-850 nm provides an opportunity to fully explore the potential of SIF in estimating GPP. Using high-frequency measurements of canopy carbon flux and SIF emissions at the atmospheric absorption bands, we reconstruct the full SIF spectrum from SIF signals at the absorption bands, and then analyze correlations between the GPP and the selected single SIF bands and their combinations using both linear regression (LR) and Gaussian processes regression (GPR). Our results indicate that (1) the red SIF bands (640-700 nm) shows low correlation with GPP due to the strong (re)absorption of red SIF emissions by leaf chlorophyll; (2) the individual bands in near-infrared area (at 720 nm, 740 nm, and 761 nm) can determine about 60% and 62% of the variance in GPP with hourly scale by LR and GPR, respectively, and the combination of those SIF bands provide increased predictive power, explaining 66% and 76% variance in GPP with hourly scale by LR and GPR, respectively; (3) the solar radiation saturation, fraction of direct solar radiation, air temperature and leaf area index may have negative impacts on the SIF-GPP correlations when they are beyond optimal thresholds; and (4) the temporal aggregation of SIF-GPP (daily scale) enhances the correlations as compared with the hourly scale: the daily combination of SIF bands (at 687 nm, 720 nm, and 761 nm) can account for 80% and 93% of variance in daily daytime GPP by LR and GPR, respectively, suggesting that the combination of these three bands of SIF on the daily scale is the best proxy for GPP. Our results provide a new approach to analyze the SIF-GPP correlations using the ground-based full broadband SIF emission, suggesting that multi-bands SIF has a stronger capacity in predicting plant GPP than traditionally used signal band SIF data.

Coastal blue carbon refers to the carbon taken from atmospheric CO2; fixed by advanced plants (including salt marsh, mangrove, and seagrass), phytoplankton, macroalgae, and marine calcifiers via the interaction of plants and microbes; and stored in nearshore sediments and soils; as well as the carbon transported from the coast to the ocean and ocean floor. The carbon sequestration capacity per unit area of coastal blue carbon is far greater than that of the terrestrial carbon pool. The mechanisms and controls of the carbon sink from salt marshes, mangroves, seagrasses, the aquaculture of shellfish and macroalgae, and the microbial carbon pump need to be further studied. The methods to quantify coastal blue carbon include carbon flux measurements, carbon pool measurements, manipulative experiments, and modeling. Restoring, conserving, and enhancing blue carbon will increase carbon sinks and produce carbon credits, which could be traded on the carbon market. The need to tackle climate change and implement China’s commitment to cut carbon emissions requires us to improve studies on coastal blue carbon science and policy. The knowledge learned from coastal blue carbon improves the conservation and restoration of salt marshes, mangroves, and seagrasses; enhances the function of the microbial carbon pump; and promotes sustainable aquaculture, such as ocean ranching.