长江口外颗粒有机碳及光合色素在不同溶氧水平下早期降解速率研究

有机质降解是低氧形成的重要原因.长江口外的低氧近几十年来日趋恶化,引起了大量学者关注,但现场有机质降解及相关的耗氧速率还鲜见报道.本研究通过人工控制体系溶氧(DO)水平,于2006年10月在曾经出现低氧的长江口外近海进行现场有机质降解培养实验,以模拟有机质在沉降进入近底层水后早期(9天)内的生物地球化学过程,估算有机碳降解速率和耗氧速率.培养实验表明,有机质在几天内即可出现明显的降解,并伴随体系pH的下降和细菌、病毒的增加.体系溶氧对有机碳(POC)降解速率影响较大,POC在DO＞95％条件下的降解速率是DO＜50％条件下的5倍,分别为1.5 mmol/(m3·d)和0.3 mmol/(m3·d).光合色素岩藻黄素(FUCO)和叶绿素a(Chla)含量在9天内呈指数下降,其中80％的FUCO在9天内发生了降解.指数方程能较好地实现对观测数据的拟合,结果表明Chl a的半衰期为3-4天.不同溶氧条件下的结果表明低溶氧条件(DO＜50％)下浮游植物更容易成为降解有机质的来源.根据POC降解速率估算得到长江口外溶氧消耗速率分别为82-91 mmol/(m2·d)(DO＞95％条件)和27-30 mmol/(m2·d)(DO＜50％条件),远高于深海氧通量和表层50 m南海的氧消耗通量;以此耗氧速率为基础,估算得到长江口外层化形成至发育出低氧的时间为50-150天.     

Glyphosate persistence in seawater

Glyphosate is one of the most widely applied herbicides globally but its persistence in seawater has not been reported. Here we quantify the biodegradation of glyphosate using standard “simulation” flask tests with native bacterial populations and coastal seawater from the Great Barrier Reef. The half-life for glyphosate at 25 °C in low-light was 47 days, extending to 267 days in the dark at 25 °C and 315 days in the dark at 31 °C, which is the longest persistence reported for this herbicide. AMPA, the microbial transformation product of glyphosate, was detected under all conditions, confirming that degradation was mediated by the native microbial community. This study demonstrates glyphosate is moderately persistent in the marine water under low light conditions and is highly persistent in the dark. Little degradation would be expected during flood plumes in the tropics, which could potentially deliver dissolved and sediment-bound glyphosate far from shore.     

Degradation of Rhodamine B and Safranin‐T by MoO3:CeO2 Nanofibers and Air Using a Continuous Mode

One‐dimensional MoO₃ nanofibers doped with Ce (MoO₃ : CeO₂) are synthesized by a method combining a sol‐gel process and an electrospinning technique. The resulting MoO₃ : CeO₂ is characterized by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT‐IR) spectroscopy, and scanning electron microscopy (SEM). The catalytic degradation of rhodamine B and safranin‐T with MoO₃ : CeO₂ nanofiber catalyst is investigated in a continuous flowing mode using air (O₂) as an oxidant. The results show that rhodamine B and safranin‐T are degraded effectively and the removal efficiencies are 98.3%, and 98.5%, respectively. In addition, the organic dyes are totally mineralized to simple inorganic species such as CO₃^–, Cl^– and NO₃^–.     

Notes on the origin of inertinite macerals in coals: Observations on the importance of fungi in the origin of macrinite

Macrinite is a, generally, rare inertinite maceral, often incorporating remnants and fragments of other macerals, including vitrinite, liptinite, and other inertinite. The associated inertinites include multiple forms of funginite. Funginite is also commonly found in association with vitrinite of slightly elevated reflectance and with degraded varieties of vitrinite. Together with the highly degraded macrinite, the latter two associations are here inferred to be part of a continuum of fungal and microbial degradation of peat. In any case, the origin of some macrinite is potentially distinct from that of inertinite generated by fire.     

河流中污染物衰减系数影响因素分析

污染物衰减系数是反映河流水质污染变化情况、建立水质模型、计算水环境容量的重要参数之一,其确定的合理性直接影响到水环境容量以及水质模型的可靠性。通过查阅有关文献,概述了国内外部分河流的COD和BOD以及氨氮的衰减系数,并分析了影响污染物衰减系数的主要因素,为研究河流水体自净规律、计算水环境容量、区域排污总量控制计划的制定提供科学依据。     

ON THE PREDICTION OF TRANSIENT BED LEVELS DUE TO AGGRADATION AND DEGRADATION INCLUDING ARMOURING

ＯＮＴＨＥＰＲＥＤＩＣＴＩＯＮＯＦＴＲＡＮＳＩＥＮＴＢＥＤＬＥＶＥＬＳＤＵＥＴＯＡＧＧＲＡＤＡＴＩＯＮＡＮＤＤＥＧＲＡＤＡＴＩＯＮＩＮＣＬＵＤＩＮＧＡＲＭＯＵＲＩＮＧＡ．Ｂ．ＰＡＬＡＮＩＡＰＰＡＮ１,Ｒ．Ｊ．ＧＡＲＤＥ２ａｎｄＰ．Ｎ．ＧＯＤＢＯＬＥ３...     

海洋浮游植物分解和代谢产物中高分子有机物的紫外、红外和~1H-核磁共振光谱特征

用GDX 102树脂从海洋浮游植物三角褐指藻(Phaeodactylum tricornutum)的分解产物和代谢产物中分离提取腐植类物质(DHS,EHS)及乙醇可溶物(DES,EES),用~1H-NMR,IR和UV光谱进行结构分析,并同海水中腐植质(HS)和乙醇可溶物(ES)做了比较。结果表明,DHS,EHS和HS都以高支链烷烃、碳水化合物和氨基酸结构为主要组分,另有少量芳烃和杂环化合物。它们的化学结构很相似,说明DHS和EHS是海水腐植质的重要来源。     

From Objective Environmental Problems to Subjective Environmental Concern: A Multilevel Analysis Using 30 Indicators of Environmental Quality

This article analyzes the effect of environmental degradation, the affluence hypothesis, and postmaterialist theory to assess the environmental concern of individuals in 51 countries. The hypotheses are tested using a multilevel analysis that employs an unprecedented number of objective indicators of environmental degradation, using the World Values Survey 6th wave (2010–2014). The results support the degradation hypotheses, where the importance of water scarcity in a country and national biodiversity are the major variables that explain individual environmental concern among all the indicators of environmental degradation. The affluence hypothesis is rejected and the postmaterialist theory is supported only at the individual level.     

Assessment of climate change adaptation costs for the U.S. road network

The U.S. road network is one of the nation's most important capital assets and is vital to the functioning of the U.S. economy. Maintaining this asset involves approximately $134 billion of government funds annually from Federal, State, and local agencies. Climate change may represent a risk or an opportunity to this network, as changes in climate stress will affect the resources necessary for both road maintenance and construction projects. This paper develops an approach for estimating climate-related changes in road maintenance and construction costs such that the current level of service provided by roads is maintained over time. We estimate these costs under a baseline scenario in which annual mean global temperature increases by 1.5 °C in 2050 relative to the historical average and a mitigation scenario under which this increase in mean temperature is limited to 1.0 °C. Depending on the nature of the changes in climate that occur in a given area, our analysis suggests that climate change may lead to a reduction in road maintenance and/or construction costs or an increase in costs. Overall, however, our analysis shows that climate change, if unchecked, will increase the annual costs of keeping paved and unpaved roads in service by $785 million in present value terms by 2050. When not discounted, this figure increases to $2.8 billion. Policies to reduce greenhouse gas emissions are estimated to reduce these costs by approximately $280 million in present value terms and by $885 million when not discounted. These costs vary substantially by region and time period, information that should be important for transportation planners at the national, state, and local levels.