Sedimentary geochemical record of human-induced environmental changes in Huanggaihu Lake in the middle reach of the Yangtze River, China

Abstract

Total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP) and

Recent Sedimentation Rates of Shallow Lakes in the Middle and Lower Reaches of the Yangtze River: Patterns, Controlling Factors and Implications for Lake Management

“…Consequently, the contribution of shallow lakes to the sedimentation rates is difficult to discern. Similar studies in other lakes of the MLYB region, suggest that disturbances in catchments (e.g., soil erosion) may be the main cause of SR variation in MLYB [30].…”

“…Traditional land uses are agriculture, forestry, paddies and urban settlements. The past 100 years, particularly the recent 30 years, have seen rapid growth of the local population and fast economic development in the study region; the consequent expansion of material and recreational needs has changed the land use, causing increased soil erosion in the catchment [16,30,40]. At the same time, the construction of water conservation facilities has altered the original connectivity of the Yangtze River, creating a sharp rise in sediment accumulation rates and loss of water volume in lakes [41].…”

“…By contrast, Wu et al [27] found that the building of water conservancy facilities (e.g., sluice gates) affected sedimentation rates by controlling the outflow/inflow of sediments or changing the hydrodynamic force (due to the changes in water flow rates) for particle deposition. Yao and Xue [30] pointed out that the sediment accumulation rates in the large-sized lakes in MLYB generally do not reflect the catchment erosion history but that relatively small lakes are sensitive to catchment disturbance [29]. In most situations, land use intensity and fresh water use, which may affect sedimentation rates, are decisive for the water quality and ecological functioning of lakes in MLYB, and significant changes in eutrophication and unsustainable land use practices have become a widespread problem, in particular since the reform and opening-up policy era, i.e., 1980s [8,[31][32][33].…”

Complexities of Stable Carbon and Nitrogen Isotope Biogeochemistry in Ancient Freshwater Ecosystems: Implications for the Study of Past Subsistence and Environmental Change

“…A less obvious but nonetheless important source of anthropogenic nutrient loading is through soil erosion. Human land management practices, especially deforestation and the intensive agricultural activities that can follow (such as stump removal and plowing) may destabilize soils and lead to large scale losses of soil nutrients through runoff (Sudduth et al, 2013) which can in turn alter the stable nitrogen isotopic composition of adjacent aquatic ecosystems (Vandermyde and Whitledge, 2008;Massa et al, 2012;Theissen et al, 2012;Yao and Xue, 2015). Prior to and during transport from terrestrial to aquatic ecosystems, soil nutrients could pass through a range of biological and physical processes that can cause isotopic fractionation (Hogberg, 1997;Hobbie and Ouimette, 2009;Nikolenko et al, 2018).…”

Enhancement of sediment phosphorus release during a tunnel construction across an urban lake (Lake Donghu, China)

“…Furthermore, explanation of the mechanisms involved is largely limited to elevated rates of soil erosion. In a sediment core of Lake Huanggaihu, located in the middle reach of the Yangtze River, China, high sediment mass accumulation rates and low clay content suggested increased catchment erosion related to human activities such as railway construction and forest clearing during the 1910s-1940s in the catchment area (Yao and Xue 2015). During urban development, rates of soil erosion can climb to levels that are typically 200 times above background conditions, with the eroded sediments entering waterways and causing harm to the biota living therein, which has been identified as a contributor to the eutrophication of Lake Simcoe (Trenouth et al 2013).…”