Potential impacts of climate and anthropogenic-induced changes on DOM dynamics among the major Chinese rivers

Dissolved organic matter (DOM) is closely linked to human activities in drainage basins and plays a crucial role in maintaining ecosystem functioning and reflecting environmental quality. However, the impacts of climate and anthropogenic-induced changes on DOM in riverine systems under increasingly warming conditions still need to be better understood, particularly at large regional scales. To address this knowledge gap, we analyzed a dataset containing 386 published measurements for nine major Chinese river systems, examining dissolved organic carbon (DOC) concentrations and optical properties of chromophoric DOM (CDOM) under diverse envi- ronmental conditions, including mean air temperature, precipitation, surface solar radiation, population density, and land use. Our findings indicate that riverine DOC concentrations are significantly higher in northern China (at ∼46.8%) than in the south. This disparity is primarily due to the high input of soil erosion-induced DOM from drying-affected lands (57.0%), farmland (49.1%), and forests in the north. The high temperate and strong hydrological conditions would lead to DOM degradation easily in the riverine system in the south of China. Our study highlights that various climatic and anthropogenic factors, such as agriculture, vegetation coverage, soil erosion, surface solar radiation, and precipitation, individually or in combination, can affect DOM dynamics in river systems. Therefore, considering alterations in DOM dynamics resulting from climate and environmental changes is crucial for carbon-neutral policies and sustainable river ecosystem assessments.

Distribution and reproductive behavior of penguins on Ardley Island and their environmental impact factors

During the 2006/07 Antarctic summer,the species population,distribution and reproductive behavior of penguins in areas near the Great Wall Station were investigated.Five species of penguin were recorded：gentoo penguin（Pygoscelis papua）,adelie penguin（P.adeliae）,chinstrap penguin（P.antarctica）, King penguin（Aptenodytes patagonicus） and Emperor penguin（A.forsteri）. The first three species bred locally,while the other two species were observed occasionally.Ardley Island is one of the most important breeding areas for penguins.After the breeding season of 2006/07,there were a total of about 17 234 penguins and the breeding success rate was 0.40—1.41.Comparing with historical data,changes in penguin species populations and distribution were analyzed, and their relationships with the environment,climate change and human activity were investigated.

Governing Climate Change Risks： Implications for Mitigation and Adaptation

This article analyzed climate change risks from the perspective of con- temporary environmental risks and how they have been internalized by policy. In order to do so, the main characteristics of this type of risk were analyzed based on the contributions from social theory authors on contemporary environmental risks. Next, the implications of these characteristics for the production of policy responses to climate change risks were discussed. The two main types of policy responses to climate change in the literature were presented： mitigation and adaptation. Finally, their interaction, differences and possibilities for synergy were analyzed. Under- standing climate change as a contemporary environmental risk, the way it was presented in this article, implies a radical change in the development bases of society, since greenhouse gases emissions from human activities contribute to the aggravation of global warming. Climate change challenges the traditional ways of governing in many ways, since climate change policy should involve the ques- tioning of the current processes of development. Profound changes in ways of thinking and established political action are needed.

Sedimentary and OSL dating evidence for the development of the present Hobq desert landscape, northern China

The sedimentary sequence and landscape of the Hobq desert was observed through twelve profiles along five N-S sections extending through the entire desert.Aeolian sands were found to overlie the alluvial,diluvial,and lacustrine sediments in this desert.Optically stimulated luminescence(OSL)dating results were obtained from post-IR OSL signals of quartz fractions of sand samples at the bottom of sand dunes and hills by using the Double-SAR protocol.The OSL ages reveal that the latest sand accumulation began around 19 ka in the northwestern part and 9 ka in the eastern part of the Hobq Desert.Around 7 ka,the sand accumulation was strengthened and extended southward and northward 2 ka to develop the present desert landscape.Our study suggests that the aeolian sand accumulation around 19,9 and 7 ka resulted from the weakening of the Asian summer monsoon over this region.However,the rapid development of the present Hobq desert landscape since 2 ka was likely triggered by human activities in this desert.