Since the drinking water crisis triggered by the cyanobacterial bloom in 2007, extensive and high-intensity pollution control and ecological restoration carried out in the entire Taihu basin. 
　　Ten years later, water quality improved according to some variables; however, the cyanobacterial bloom has not been effectively contained in Lake Taihu. Total phosphorus concentrations have even increased in recent years, intense cyanobacterial blooms have persisted through 2017 with a record-setting bloom occurring in May, 2017. 
　　The contradiction between water quality and cyanobacteria bloom fluctuations and intensity management in Taihu Basin is confusing. The effectiveness of scientific and precise restoration of Lake Taihu has been widely questioned, further implementation of Lake Taihu management and the formulation of ecological restoration programs were also hindered. 
　　Recently, an international research group led by Prof. QIN Boqiang from the Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences (NIGLAS), carried out multidisciplinary research and proposed that regional extreme climatic anomalies could intensify nutrients cycling in the water-sediment interface and promote the cyanobacterial blooms in Lake Taihu. 
　　The study was recently published in Water Resources Research.
　　Multi-source data analysis showed that the abnormally high rainfall in the Taihu Basin in 2016 led to a sharp increase in external loading. At the same time, the winter temperature of 2016/2017 was the highest value since the 1960s, resulting in a high value of overwintering cyanobacteria biomass. The 2015/2016 super El Nino event, coupled with warm phase of the Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO), jointly induced heavy rainfall in the Taihu Basin in 2016 and the following warm winter. 
　　After the severe blooms in 2017, the pH of the water body increased and the concentration of dissolved oxygen at the bottom of the lake decreased due to photosynthesis or organic matter degradation, which promoted the internal loading and further benefit the blooms, i.e., a positive feedback among "nutrient accumulation-heavy blooms-internal loading-eutrophication aggravation”. The enhanced nutrient cycle provides a continuous nutrient for the cyanobacterial bloom persistence. 
　　This research interprets that under the big picture of global warming, regional extreme climate anomalies will further deteriorate lake water quality, promote eutrophication and cyanobacterial blooms in eutrophic lakes. 
　　This work was funded by the National Natural Science Foundation of China and the Water Pollution Control and Treatment Science and Technology Major Project.
　　Reference:
　　Extreme Climate Anomalies Enhancing Cyanobacterial Blooms in Eutrophic Lake Taihu, China
　　Fig. 1 Long-term trends of AMO, PDO, ENSO, and their relationships related to temperature anomalies and rainfall in Tahu Basin
　　Fig. 2 Conceptual diagram of a combination of climate anomalies induced internal phosphorus cycling which led to a positive feedback to ensure cyanobacterial bloom persistence

　　Dissolved organic matter (DOM) refers to various organic molecules (sugars, fatty acids, and alkanes), is ubiquitous in global lakes, provides food/energy for heterotrophic bacterial growth, and serves as a carbon pool of the global carbon cycle and climate change. Moreover, colored DOM can influence phytoplankton photosynthesis through light absorption, and DOM decomposition consumes dissolved oxygen and deteriorates water quality. 
　　Dissolved organic matter content is usually determined by dissolved organic carbon (DOC). With the advantage of having a high spatiotemporal resolution, satellite-based data are optimal for dynamically monitoring DOC dynamics. However, only some empirical band combination algorithms have been proposed for regional lakes, and long-term series DOC satellite products for eutrophic lakes have not been published. 
　　Lake DOC has two source types. Autochthonous DOC is mainly derived from phytoplankton through extracellular release and cell degradation. Allochthonous DOC is primarily transported from the terrestrial ecosystem by input rivers. To understand the carbon cycle in a eutrophic lake, it is indeed necessary to know its DOC storage and the DOC exchange fluxes between the lake and surrounding rivers. 
　　Globally, lake eutrophication is a common problem, and approximately 63% of lakes with areas > 25 km2 are characterized by eutrophication. Machine learning has achieved exceptionally satisfactory results in remotely retrieving aquatic environmental variables in complex inland waters. Taking the typical eutrophic Lake Taihu as a study area, we realize the observation of lake DOC storage and exchange flux from space. 
　　For Lake Taihu, the DOC distributions were spatially consistent with those of phytoplankton content (Chl-a), and high DOC concentrations were observed in the northwestern lake bays. The satellite-derived monthly climatology DOC level displayed spatial distributions similar to those of the annual mean results, with high values in the northwest lake bays. What is noteworthy is that low DOC was observed in the Tiaoxi River estuary in the South Taihu. 
　　In Lake Taihu, the annual-monthly mean DOC level increased from 2003–2018. A positive relationship was found between the annual mean DOC level and Chl-a. As with the in-situ data, satellite-derived DOC levels were high in summer July and September, when Chl-a levels were also high. In contrast, the DOC level was low in June, when high basin precipitation diluted riverine input DOC. 
　　Annual input and output DOC fluxes by surrounding rivers varied greatly from year to year during 2008-2018. By dividing the lake DOC storage by the total DOC input flux, we obtained that the turnover time for riverine input DOC in Lake Taihu was approximately 24–43 days during 2008–2018. 
　　Although the mean net riverine DOC input was approximately 5.2 times the lake DOC storage volume during 2008-2018, DOC variations in Lake Taihu were controlled by phytoplankton growth. Therefore, terrigenous DOC was quickly transformed into other carbon forms after entering Lake Taihu. These indicate that the low dissolved oxygen level in Lake Taihu might be related to the decomposition of the large amount of terrigenous DOC.
　　Paper link:https://www.sciencedirect.com/science/article/pii/S0034425721002923
　　 

The Chinese civilization is the oldest and most enduring in the world. During its long lasting “5000-year” history, China has experienced a series of centennial-scale rise and fall of dynasties, unifications and divisions, war and peace and south-north migration of northern nomads. Climate changes have long been proposed as an important driver of these historical cultural changes through affecting phenology and land productions, especially for China as a traditional farming civilized society. As early as the 1970s, Chu, (1972) first reported the temperature history of China over the past “5000-year” based on phenological documents and pioneered the study of climate and dynasty transitions. Over the past few decades, many efforts have been taken to reconstruct the climate records, but mostly qualitatively. Lack of high-resolution, quantitative climate records, especially for the heartland of ancient Chinese culture, limits a comprehensive examination of the relation between climate and culture changes in Chinese history. A scientific research group, composed of Nanjing Institute of Geography and Limnology, Institute of Tibetan Plateau Research, Nanjing University and other institutions, presents well-dated, high resolution, quantitative warm-season temperature and annual mean precipitation records and provides a high-quality climate background for the entire “5000-year” Chinese history. Results suggest that changes in temperature and precipitation are incomplete coupled in terms of both long-term trend and centennial-scale variability before ~1000 CE (Common era). The temperature displays a slight decrease of ~0.5oC before ~200 CE and a rapid cooling of ~4oC afterwards, superimposed with four 1-2oC centennial-scale cold events. The precipitation shows high value before ~1000 BCE and a gradual decrease of ~250 mm with two distinct ~100 mm centennial scale dry intervals after ~1000 CE. Climate changes in dynastic China indicate that the Three Sovereigns and Five Emperors began in a relatively warm and wet climate, and the moderate conditions lasted until Shang Dynasty followed by a gradually cold and dry climate with large fluctuations afterward. Specifically, we find cold-dry conditions in the late Tang, Five Dynasties and Ten Kingdoms (5D&10K), late Song, Yuan, late Ming Dynasty, and only cold conditions during the period of the Spring and Autumn and Warring States (SAWS), the period of Wei, Jin and Southern and Northern Dynasties (WJSN). It shows the three long-term and large-scale social unrests (5D&10K, SAWS, WJSN) in Chinese history have experienced large climate fluctuations. Comparison of climate changes and other social factors reveals some centennial-scale cold and/or dry oscillations are also accompanied by an increase of war frequency, a sharp decline of population size and a southward migration of northern nomads during three large-scale social unrests of SAWS, WJSN and 5D&10K, and nomadic dynasties (Yuan and Qing Dynasty) when northern nomads ruled the central plains. Thus, climate fluctuations likely played an important role in affecting cultural changes in the “5000-year” Chinese history. Dynasty transitions may also be influenced by other sociocultural factors and administrative efficiency such as class struggle, peasant uprising, economic collapses and misgovernment. For example, the end of some dynasties such as Xia, Shang and Qin Dynasty occurred under a background of stable climate, and ~70 years of cold event at ~750 CE did not lead to the end of the prosperous Tang Dynasty although it likely corresponds to the famous An-Shi Rebellion. Climate change may be not a decisive factor of dynastic transitions, although it has an important impact on Chinese historical cultural changes. Therefore, we must avoid falling into the trap of “geographical determinism” when discussing the relation between both. Our high-resolution quantitative climate records just provide crucial climate context to test the hypothesis of climatic impact on historical culture changes.
　　Quantitatively reconstructed temperature (a) and precipitation (b). Frequency of wars in China (c). Population size of China (d). South limit of nomadic national regime with boundary the GreatWall in Inner Mongolia (e). 
　　Paper link: https://www.sciencedirect.com/science/article/pii/S0277379121000263