In recent years, scientists have focused on the karst carbon cycle. To better understand the hydrochemical characteristics and the physical-chemical properties of DOC in the wet season in karst areas, the water chemistry and DOC distribution characteristics in Wulixia reservoir were analyzed. The molecular weight of the water organic matter was analyzed based on the UV absorption spectrum. The results showed that the water chemistry of Wulixia reservoir was HCO-Ca ·Mg, the nutrient status of the water body was of the medium nutrient type, and the water maintained a good quality. The DOC mass concentration was lower in the wet season than in the dry season, and DOC was the main component of TOC. The DOC mass concentration tended to decrease from the surface to the bottom in a vertical direction. Chl-a and DIC were the main factors affecting the DOC vertical distribution. The organic matter in the reservoir area related to the absorption spectrum parameters of , , SUVA, and / showed that the water was dominated by constituents with small molecular weight, a high proportion of fulvic acid, low proportion of humic acid, and weak aroma. The results showed that the organic matter in the reservoir area was readily consumed by microbial bioactivity and that it played an active role in the carbon cycle of the reservoir. It also showed that the DOC endogenous characteristics of the reservoir were strong and provided a sufficient carbon source for heterotrophic microbes.
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http://dx.doi.org/10.13227/j.hjkx.201708032 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Research Applications Laboratory, NSF National Center for Atmospheric Research, Boulder, CO 80301.
Precipitation recycling, where evapotranspiration (ET) from the land surface contributes to precipitation within the same region, is a critical component of the water cycle. This process is especially important for the US Corn Belt, where extensive cropland expansions and irrigation activities have significantly transformed the landscape and affected the regional climate. Previous studies investigating precipitation recycling typically relied on analytical models with simplifying assumptions, overlooking the complex interactions between groundwater hydrology and agricultural management.
View Article and Find Full Text PDFAfrican elephants () are megaherbivores of the African savannas requiring extensive ranges that can provide critical resources for their survival and reproduction at different spatiotemporal scales. We studied seasonal differences in home range sizes and daily distance to the nearest surface water sources by five male and 10 female African elephants in the eastern Okavango Panhandle in northern Botswana between 2014 and 2017. We hypothesized that (i) elephant home ranges would be larger in the wet than in the dry season (because critical resources tend to be less localized in the wet than in the dry season), (ii) the daily distance of the elephants to the nearest ephemeral surface water sources would be larger in the dry than in the wet season because many of the ephemeral water sources would be dry in the dry season and elephants would start moving towards permanent water sources such as rivers, and lastly (iii) that the differences in elephant home ranges and daily distance to water would differ between sexes.
View Article and Find Full Text PDFWater Environ Res
January 2025
Department of Environmental Sciences, Hydrobiogeochemistry and Pollution Control Laboratory, Jahangirnagar University, Dhaka, Bangladesh.
This study was carried out to determine the current state of the physicochemical water quality parameters and the effects of urbanization over 50 years in the peripheral rivers by using primary and secondary data adjacent to Dhaka city. These rivers and waterways had DO levels much below the recommended standard of Bangladesh, and occasionally, they even approached 0. This suggests that the water in these rivers is highly polluted and unfit for aquatic life.
View Article and Find Full Text PDFPathogens
December 2024
Institute of Pest Management, Sokoine University of Agriculture (SUA), Morogoro 67101, Tanzania.
J Environ Manage
January 2025
Université Paris-Saclay, CNRS, IRD, UMR Évolution, Génomes, Comportement et Écologie, Gif-sur-Yvette, France; International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya. Electronic address:
In recent decades, worldwide concerns about the health of honey bees motivated the development of surveys to monitor the colony losses, of which Sub-Saharan Africa has had limited representation. In the context of climate change, understanding how climate affects colony losses has become fundamental, yet literature on this subject is scarce. For the first time, we conducted a survey to estimate the livestock decrease of honey bee colonies in Kenya for the year 2021-2022 to explore the effects of environmental conditions, such as temperature and precipitation, on livestock decrease.
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