Characteristics and indications of hydrogen and oxygen isotopes distribution in lake ice body.
Stable isotopes have been used to identify the characteristics of precipitation, evaporation, basin hydrology, and residence times. However, lakes in the cold regions are usually covered by ice for 5-6 months. To get a better understanding of stable isotopes characteristics and indications in lake ice bodies, ice and water were sampled during the icebound season in both the ice and water bodies in Dali Lake, and deuterium, oxygen-18 total nitrogen (TN), and the major ions were analyzed. The results showed that deuterium and oxygen-18 compositions (δD-δ¹⁸O) compositions in the ice body were greater than in the water body beneath, scattered on a straight line, and deviating downward from the global meteoric water line in the top right. The ice profile showed that the δD-δ¹⁸O compositions increased from the ice surface downward and decreased near to the bottom. In contrast, the TN and the major ions in the ice decreased from the ice surface downward and increased near to the bottom, meaning that the concentrations of δ¹⁸O had a negative correlation with the concentrations of TN and major ions. These indicated that stable isotopes can be used for tracing the nutriment and ion transport processes in the ice body.
Environment Variation in North Margin of East Asian Summer Monsoon Record in Dali Lake over Past 168 Years
Lakes close to the limit of East Asia summer monsoon (EASM) are sensitive to the climate changes, which record significant information about environmental changes and human activities. One sediment core was collected from Dali Lake in north EASM margin of China and high-resolution multi-proxies are analyzed. The constant rate of supply (CRS) model based on 137Cs and 210Pb contents is established and provides a detail history of EASM variability and environmental changes over past ~168 years. The period from ~1847 to 1900 AD was characterized by the steady values of total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC) and C/N and decrease in δ13Corg values reflected slightly enhanced EASM. The period between ~1901 to 1944 AD, δ13Corg values indicated EASM first decrease and then increase. The gradually increased TN, TP and TOC values and the decreased C/N ratios indicated the shrink of the lake area caused by the higher evaporation and autochthonous OM increased. From ~1945 to 2015 AD, the increased values in TN, TP and TOC may be mainly caused by the shrink of the lake area and the enhanced human activities, and δ13Corg values suggested a fluctuant EASM in this period. Mercury (Hg) element in Dali Lake sediments gradually increased since 1847 AD while it was constant in the interval of ~1944−1959 AD and then kept increasing, which may be caused by the increased Hg content in atmosphere from Europe and other industrial area. The EASM variability over past ~168 years showed the trends were similar to EASM records in other regions of China. Furthermore, our findings indicated that the variability of the EASM was forced by changes in oceanic-atmospheric circulation interaction.
Indian Fig Cactus (Opuntia Ficus-Indica (L.) Miller) in the Americas: an Uncertain History
Abstract: 
 Opuntia ficus-indica (L.) Miller is a globally important cactus species with a long history of human use. In addition to the importance of O. ficus-indica as a food for humans and livestock, it also has long served a role in the production of cochineal, a once important textile dye. This cactus also is intimately interwoven into the story of Cactoblastis cactorum (Berg) (South American cactus moth), one of the best-known examples of biological weed control. In this regard, O. ficus-indica has been a target weed as well as an unintended host in C. cactorum invasion. Although the distribution and human-assisted movement of this cactus throughout much of the world is well documented, surprisingly little has been written about its history and movement within the Americas. Literature associated with Opuntia and their phytophagous pests in North and South America was examined in an attempt to determine the history of O. ficus-indica in the Americas. Available information suggests with some certainty that O. ficus-indica originated in present-day Mexico, but the timing of its introduction to South America is much less clear. Taxonomic difficulties associated with distinguishing among Opuntia species and the long pre-Columbian history of exchange between South American and Mesoamerican cultures are two primary complicating factors associated with dating the dispersal of this species to South America. Additionally, previous evidence in support of a pre-Columbian introduction to South America relied on questionable identification of insect-based textile dyes. These uncertainties are significant because clearer knowledge of the history of O. ficus-indica introduction to South America could provide a more complete biological and ecological context to efforts at managing this species in its native and introduced ranges, particularly with respect to the threat posed by C. cactorum in North American and Argentinean plantations.