The Secchi disk depth to water depth ratio affects morphological traits of submerged macrophytes: Development patterns and ecological implications.

Water clarity, represented by Secchi disk depth (SD), and water depth (WD) alter bottom light availability, and SD/WD is critical for morphological trait development of submerged macrophytes in freshwater ecosystems. However, the underlying mechanism and trait development patterns of submerged macrophytes to a decreasing SD/WD gradient remains largely unknown. Here, we performed a 42-day mesocosm experiment with the erect type submerged macrophyte, Hydrilla verticillata, along a decreasing SD/WD gradient to study the relationship of morphological trait development with light availability, to determine the critical SD/WD at which changes in the development of morphological traits occur, and to gain insights into the potential mechanism involved.

Driving forces and recovery potential of the macrophyte decline in East Taihu Lake.

Macrophytes are of key importance to the structure and ecological services of shallow lakes and are sensitive to anthropogenic and natural perturbations. Ongoing eutrophication and hydrological regime change affect macrophytes through changes in water transparency and water level, which lead to a dramatic decrease in bottom light availability. Here an integrated dataset (2005-2021) of multiple environmental factors is used to demonstrate the driving forces and recovery potential of the macrophyte decline in East Taihu Lake by using a critical indicator, which is the ratio of the Secchi disk depth to the water depth (SD/WD).

Distribution, driving forces, and risk assessment of 2-MIB and its producer in a drinking water source-oriented shallow lake.

Freshwater blooms of harmful cyanobacteria in drinking water source-oriented shallow lakes affect public health and ecosystem services worldwide. Therefore, identifying 2-methylisoborneol (2-MIB)-producing cyanobacteria and predicting the risks of 2-MIB are critical for managing 2-MIB-infected water sources. Previous studies on the potential producers and risks of 2-MIB have focused on reservoirs or have been limited by the ecosystems of phytoplankton-dominated areas.

Impact of submerged macrophytes on growth and 2-MIB release risk of Pseudanabaena sp.: From field monitoringa to cultural experiments.

The off-flavor compound 2-methylisoborneol (2-MIB) is generally associated with the proliferation and metabolism of filamentous cyanobacteria in shallow freshwater ecosystems. Here field monitoring in East Taihu Lake from July to October 2021, along with cultural experiments, was conducted to determine the impact of submerged macrophytes on the growth and 2-MIB production of filamentous cyanobacteria. Pseudanabaena sp.

Morphological responses of the submerged macrophyte Vallisneria natans along an underwater light gradient: A mesocosm experiment reveals the importance of the Secchi depth to water depth ratio.

Bottom light availability (BLA), represented by the ratio of the Secchi disk depth to water depth (SD/WD), plays a fundamental role in the growth and reproduction of submerged macrophytes. However, studies thus far have mainly explored the interactions between macrophyte responses and BLA through field investigations; this means that knowledge of such responses to various underwater light conditions in mesocosm experiments is rudimentary at best. We hypothesized that the growth and clonal reproduction of submerged macrophytes decrease with decreasing BLA and collapse beyond a critical threshold.

The role of mechanical harvesting on the recession of aquatic vegetation under an extreme water level increase in a eutrophic shallow lake.

Mechanical harvesting is quick and effective way to remove nuisance macrophytes and improve recreational use and aesthetics in shallow lake. However, applying mechanical harvesting to macrophytes in eutrophic shallow lake with weak resilience and strong perturbation raises concerns of the public and scientific communities. A combination of field investigation and remote sensing was used to determine the potential driving factors of macrophyte degradation in a eutrophic shallow lake from 2014 to 2017, including a comparative analysis of preserved and harvested areas to determine the impacts of mechanical harvesting.

Embedded reservoir and constructed wetland for drinking water source protection: Effects on nutrient removal and phytoplankton succession.

An embedded reservoir that provides an efficient nutrient removal system protects drinking water. However, embedded reservoirs are rarely used in eutrophic shallow lakes because of their undetermined nutrient retention efficiency and unknown effects by the phytoplankton community. In this study, we aim to investigate the nutrient retention and algae succession in an embedded reservoir and adjacent wetland from April 2017 to September 2018 in the eastern part of Lake Taihu, China.