Unlabelled: The Pacific white shrimp (Litopenaeus vannamei) is widely used in aquaculture, where it is reared at high stocking densities, temperatures, and nutrient concentrations. Here we report that adult L. vannamei shrimp emit the greenhouse gas nitrous oxide (N2O) at an average rate of 4.3 nmol N2O/individual × h, which is 1 to 2 orders of magnitude higher than previously measured N2O emission rates for free-living aquatic invertebrates. Dissection, incubation, and inhibitor experiments with specimens from a shrimp farm in Germany indicated that N2O is mainly produced in the animal's gut by microbial denitrification. Microsensor measurements demonstrated that the gut interior is anoxic and nearly neutral and thus is favorable for denitrification by ingested bacteria. Dinitrogen (N2) and N2O accounted for 64% and 36%, respectively, of the nitrogen gas flux from the gut, suggesting that the gut passage is too fast for complete denitrification to be fully established. Indeed, shifting the rearing water bacterial community, a diet component of shrimp, from oxic to anoxic conditions induced N2O accumulation that outlasted the gut passage time. Shrimp-associated N2O production was estimated to account for 6.5% of total N2O production in the shrimp farm studied here and to contribute to the very high N2O supersaturation measured in the rearing tanks (2,099%). Microbial N2O production directly associated with aquacultured animals should be implemented into life cycle assessments of seafood production.
Importance: The most widely used shrimp species in global aquaculture, Litopenaeus vannamei, is shown to emit the potent greenhouse gas nitrous oxide (N2O) at a particularly high rate. Detailed experiments reveal that N2O is produced in the oxygen-depleted gut of the animal by bacteria that are part of the shrimp diet. Upon ingestion, these bacteria experience a shift from oxic to anoxic conditions and therefore switch their metabolism to the anaerobic denitrification process, which produces N2O as an intermediate and dinitrogen (N2) gas as an end product. The N2O/N2 production ratio is unusually high in the shrimp gut, because denitrification cannot be fully established during the short gut passage time of food-associated bacteria. Nitrous oxide emission directly mediated by L. vannamei contributes significantly to the overall N2O emission from aquaculture facilities.
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http://dx.doi.org/10.1128/AEM.00396-16 | DOI Listing |
Sci Rep
January 2025
College of Ecology and Environment, Hainan University, Haikou, 570228, China.
Agroforestry systems are known to enhance soil health and climate resilience, but their impact on greenhouse gas (GHG) emissions in rubber-based agroforestry systems across diverse configurations is not fully understood. Here, six representative rubber-based agroforestry systems (encompassing rubber trees intercropped with arboreal, shrub, and herbaceous species) were selected based on a preliminary investigation, including Hevea brasiliensis intercropping with Alpinia oxyphylla (AOM), Alpinia katsumadai (AKH), Coffea arabica (CAA), Theobroma cacao (TCA), Cinnamomum cassia (CCA), and Pandanus amaryllifolius (PAR), and a rubber monoculture as control (RM). Soil physicochemical properties, enzyme activities, and GHG emission characteristics were determined at 0-20 cm soil depth.
View Article and Find Full Text PDFBr J Anaesth
January 2025
Department of Anaesthesia and Surgical Intensive Care, Changi General Hospital, Singapore, Singapore.
Biosensors (Basel)
January 2025
Department of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda 386-8567, Nagano, Japan.
Nitrogen-based fertilizers are crucial in agriculture for maintaining soil health and increasing crop yields. Soil microorganisms transform nitrogen from fertilizers into NO3--N, which is absorbed by crops. However, some nitrogen is converted to nitrous oxide (NO), a greenhouse gas with a warming potential about 300-times greater than carbon dioxide (CO).
View Article and Find Full Text PDFBioresour Technol
January 2025
Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China. Electronic address:
Mature compost can reduce gaseous emissions in composting, but its regulation mechanisms via biotic and abiotic functions are largely unknown. This study used fresh and inactivated mature compost as additives in kitchen waste composting to unveil the relevant mechanisms using metagenomic analysis. Results showed that mature compost reduce gaseous emission by improving physiochemical properties and inoculating functional microbes.
View Article and Find Full Text PDFSci Total Environ
January 2025
State Key Laboratory of Marine Resource Utilization in South China Sea, School of Ecology, School of Marine Science and Engineering, Hainan University, Haikou, Hainan, China; Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, Hainan, China. Electronic address:
The mangrove ecosystems store a significant amount of "blue carbon" to mitigate global climate change, but also serve as hotspots for greenhouse gases (GHGs: CO, CH and NO) production. The CH and NO emissions offset mangrove carbon benefits, however, the extent of this effect remains inadequately quantified. By applying the 36 h time-series observations and mapping cruises, here we investigated the spatial and temporal distribution of GHGs and their fluxes in Dongzhaigang (DZG) bay, the largest mangrove ecosystem in China, at tidal and monthly scales.
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