红树林是重要的滨海“蓝碳”生态系统,具有强大的碳汇功能,对实现“碳中和”和减缓全球气候变暖具有积极作用。本研究以瓯江口红树林沉积柱为研究对象,采用²¹⁰Pb放射性同位素测年分析沉积速率,计算有机碳埋藏速率,评估沉积物有机碳埋藏特征和来源。结果表明: 瓯江口红树林沉积物总有机碳含量平均值为1.4%,总体呈现随深度增加而逐渐降低的趋势。瓯江口红树林沉积物有机碳埋藏速率平均值为26.2 Mg C·hm^-2·a^-1,略高于全球红树林平均值;而柱状沉积物(0～150 cm)的有机碳储量平均值为37.4 Mg C·hm^-2,略低于全球红树林平均值。稳定碳氮同位素分布特征和稳定碳氮同位素混合模型(SIMMR)分析可知,沉积物有机碳来源为海陆混合来源,海源有悬浮有机颗粒和浮游植物,分别占45.6%和10.6%,陆源有沉积物有机质和凋落物,分别占31.5%和12.3%。总体上,瓯江口红树林具有较高的有机碳埋藏速率,受潮汐作用的影响不同深度沉积物碳储量存在较大差异。同时,外源性悬浮有机颗粒的输入量是影响沉积物有机碳埋藏的重要贡献者。

Mangrove forests are crucial coastal “blue carbon” ecosystems, known for their significant carbon sequestration capabilities to “carbon neutrality” and mitigating global climate change. We used ²¹⁰Pb radioisotope dating to analyze sedimentation rates in the sediments of the Oujiang River Estuary mangrove forest, to calculate organic carbon burial rate, and to assess the characteristics and sources of organic carbon burial. The results showed that the average total organic carbon content in the sediments was 1.4 %, generally decreasing with depth. The average organic carbon burial rate was 26.2 Mg C·hm^-2·a^-1, slightly higher than the global average for mangrove forests. By contrast, the organic carbon content in the core sediments (0-150 cm)was 37.4 Mg C·hm^-2, slightly lower than the global average. The stable carbon and nitrogen isotope distribution characteristics and the stable isotope mixing model (SIMMR)indicated that organic carbon originated from a mix of marine and terrestrial sources. Marine sources, such as suspended organic particles and phytoplankton, contributed 45.6% and 10.6%, respectively, while terrestrial sources, including sedimentary organic matter and leaf litter, accounted for 31.5% and 12.3%, respectively. Overall, the Oujiang River Estuary mangrove forest had a high organic carbon burial rate, with significant variations in carbon content at different depths influenced by tidal influences. Additionally, the input of external suspended organic particles was an important contributor to sediment organic carbon burial.

Mangroves are ecologically and economically important forests of the tropics. They are highly productive ecosystems with rates of primary production equal to those of tropical humid evergreen forests and coral reefs. Although mangroves occupy only 0.5% of the global coastal area, they contribute 10-15% (24 Tg C y(-1))to coastal sediment carbon storage and export 10-11% of the particulate terrestrial carbon to the ocean. Their disproportionate contribution to carbon sequestration is now perceived as a means for conservation and restoration and a way to help ameliorate greenhouse gas emissions. Of immediate concern are potential carbon losses to deforestation (90-970 Tg C y(-1))that are greater than these ecosystems' rates of carbon storage. Large reservoirs of dissolved inorganic carbon in deep soils, pumped via subsurface pathways to adjacent waterways, are a large loss of carbon, at a potential rate up to 40% of annual primary production. Patterns of carbon allocation and rates of carbon flux in mangrove forests are nearly identical to those of other tropical forests.

Although dissolved organic carbon (DOC)in soil have little proportion in the soil organic matter, it is the most important and active parts of soil organic matter. In order to study the soil DOC content and its profile distributions in different landuse, four soils with different landuse near the city of Wuhu, Anhui province, which include the farmland, vegetable plot,forest land and pen land, were selected and studied in this paper. the results can be provided a theoretical basis for understanding the role of DOC in soil carbon cycling in ecosystems and the relationship between DOC and soil fertility and fertilization. The results were as follows: (1)The concentration of dissolved organic carbon was the highest in the surface of the soil. The deeper the depth of soil, the higher the concentration was. (2)A positive correlation was found between the DOC concentrations in soil used in different ways and the soil fertility. The concentration of DOC in a way of soil use was significantly different from another. The series were that: farmland > forest > vegetable > pen land. These results indicated that the concentration of DOC had positive correlation with the soil fertility and could be used as a biological index in soil fertility.

水产养殖业作为农业面源污染的来源之一受到广泛关注,养殖尾水的污染治理已成为当前的研究热点。为了解养殖尾水净化的机理,促进净化技术效能的增强,研究介绍了中国水产养殖业污染的现状、危害和相关防治政策,并对近20年出现的水产养殖污水净化技术进行了综述。最终对养殖污水的研究进行了展望,提出可对沉淀单元进行强化、利用新型材料和微生物强化净化系统的可能性。

Wastewater from aquaculture has attracted wide attention as one of the sources of agricultural non-point source pollution, and the management of aquaculture wastewater has become a current research hotspot. In order to understand the mechanism of aquaculture wastewater purification and enhance the purification technology efficiency, this paper introduces the current status, hazards, and related control policies of aquaculture pollution in China, and reviews the aquaculture wastewater purification technologies developed in the past two decades. Finally, the research direction of aquaculture wastewater is discussed to put forward the possibility of strengthening the sedimentation unit, and using new materials and microorganisms to intensify the purification system.