Methane and nitrous oxide emissions and related microbial communities from mangrove stems on Qi'ao Island, Pearl River Estuary in China.

Mangrove forests, crucial carbon-rich ecosystems, are increasingly vulnerable to soil carbon loss and greenhouse gas (GHG) emissions due to human disturbance. However, the contribution of mangrove trees to GHG emissions remains poorly understood. This study monitored CO2, CH4, and N2O fluxes from the stems of two mangrove species, native Kandelia obovata (KO) and exotic Sonneratia apetala (SA), at three heights (0.7 m, 1.2 m, and 1.7 m) during the dry winter period on Qi'ao Island, Pearl River Estuary, China. Heartwood samples were analyzed to identify potential functional groups related to gas fluxes. Our study found that tree stems acted as both sinks and sources for N2O (ranging from -9.49 to 28.35 µg m-2 h-1 for KO and from -6.73 to 28.95 µg m-2 h-1 for SA) and CH4. SA exhibited significantly higher stem CH4 flux (from -26.67 to 97.33 µg m-2 h-1) compared to KO (from -44.13 to 88.0 µg m-2 h-1) (P < 0.05). When upscaled to the community level, both species were net emitters of CH4, contributing approximately 4.68 % (KO) and 0.51 % (SA) to total CH4 emissions. The decrease in stem CH4 flux with increasing height, indicates a soil source. Microbial analysis in the heartwood using the KEGG database indicated aceticlastic methanogenesis as the dominant CH4 pathway. The presence of methanogens, methanotrophs, denitrifiers, and nitrifiers suggests microbial involvement in CH4 and N2O production and consumption. Remarkably, the dominance of Cyanobacteria in the heartwood microbiome (with the relative abundance of 97.5 ± 0.6 % for KO and 99.1 ± 0.2 % for SA) implies roles in carbon and nitrogen fixation for mangroves coping with nitrogen limitation in coastal wetlands, and possibly in CH4 production. Although the present study has limitations in sampling duration and area, it highlights the significant role of tree stems in GHG emissions which is crucial for a holistic evaluation of the global carbon sequestration capability of mangrove ecosystems. Future research should broaden spatial and temporal scales to enhance the accuracy of upscaling tree stem gas fluxes to the mangrove ecosystem level.

Challenges of phototherapy for neonatal hyperbilirubinemia (Review).

Phototherapy is universally recognized as the first option for treating neonatal jaundice due to its unparalleled efficiency and safety in reducing the high serum free bilirubin levels and limiting its neurotoxic effects. However, several studies have suggested that phototherapy may elicit a series of short- and long-term adverse reactions associated with pediatric diseases, including hemolysis, allergic diseases, DNA damage or even cancer. The aim of the present review was to summarize the etiology, mechanism, associated risks and therapeutic strategies for reducing high neonatal serum bilirubin levels. In order to shed light on the negative effects of phototherapy and to encourage implementation of a reasonable and standardized phototherapy scheme in the clinic, the present review sought to highlight the current understanding of the adverse reactions of phototherapy, as it is necessary to further study the mechanism underlying the development of the adverse effects of phototherapy in infants in order to explore novel therapeutic alternatives.