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Yu YX, Li Y, Wang HJ, Wu XD, Zhang M, Wang HZ, Hamilton DP, Jeppesen E. Submersed macrophyte restoration with artificial light-emitting diodes: A mesocosm experiment. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 228:113044. [PMID: 34863077 DOI: 10.1016/j.ecoenv.2021.113044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 11/26/2021] [Accepted: 11/28/2021] [Indexed: 06/13/2023]
Abstract
Urban lakes are important natural assets but are exposed to multiple stressors from human activities. Submersed macrophytes, a key plant group that helps to maintain clear-water conditions in lakes, tend to be scarce in urban lakes, particularly when they are eutrophic or hypertrophic, and their loss is linked, in part, to impaired underwater light climate. We tested if enhancing the underwater light conditions using light-emitting diodes (LEDs) could restore submersed macrophytes in urban lakes. Twelve mesocosms (1000 L each) were each planted with tape grass (Vallisneria natans) and monitored over three months (22 August-7 November), using a control and three artificial light intensity treatments (10, 50, and 100 µmol m-2 s-1). Compared with the control, the high light treatment (100 µmol m-2 s-1) had higher leaf number, maximum leaf length, and average leaf length (3.9, 5.8, and 2.8 times, respectively). Shoot number, leaf number, leaf dry mass, root dry mass, and photosynthetic photon flux density in the high-light treatment were significantly greater than the control, but root length and phytoplankton chlorophyll a were not related to plant growth variables and were low in all treatments. Periphyton chlorophyll a increased significantly with the plant growth variables (i.e., shoot number, leaf number, and maximum leaf length) and was high in the light treatments but did not hamper the growth of the macrophytes. These results indicate that LED light supplementation enables the growth of V. natans under eutrophic conditions, at least in the absence of fish as in our experiment, and that the method may have potential as a restoration method in urban lakes. Lake-scale studies are needed, however, to fully evaluate LED light supplementation under natural conditions where other stressors (e.g., fish grazing) may need to be controlled for successful restoration of urban lakes.
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Affiliation(s)
- Ye-Xin Yu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China; College of Fisheries, Huazhong Agricultural University, Wuhan, China.
| | - Yan Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
| | - Hai-Jun Wang
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming, China.
| | - Xiao-Dong Wu
- College of Urban and Environmental Sciences, Hubei Normal University, Huangshi, China.
| | - Miao Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China; University of Chinese Academy of Sciences, Beijing, China.
| | - Hong-Zhu Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
| | - David P Hamilton
- Australian Rivers Institute, Griffith University, Nathan, Australia.
| | - Erik Jeppesen
- Department of Bioscience and WATEC, Aarhus University, Vejlsøvej, Silkeborg, Denmark; Limnology Laboratory, Department of Biological Sciences, Middle East Technical University, Ankara, Turkey; Sino-Danish Centre for Education and Research (SDC), University of Chinese Academy of Sciences, Beijing, China; Centre for Ecosystem Research and Implementation (EKOSAM), Middle East Technical University, Ankara, Turkey; Institute of Marine Sciences, Middle East Technical University, Mersin, Turkey.
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Li D, Zhang S, Adyel TM, Liu K, Gong L. Negative effects on the leaves of submerged macrophyte and associated biofilms growth at high nitrate induced-stress. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2020; 226:105559. [PMID: 32652412 DOI: 10.1016/j.aquatox.2020.105559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 05/20/2020] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
High nitrate (NO3--N) concentration is a growing aquatic risk concern worldwide. However, adverse effects of high NO3--N concentration on submerged macrophytes-epiphytic biofilms are unclear. In this study, the alterations in physiological changes, biofilms formation and chemical compositions were investigated on leaves of Vallisneria asiatica exposed to different NO3--N concentrations. The findings showed that 10 mg L-1NO3--N resulted in low photosynthetic efficiency by inhibiting chlorophyll content 26.2 % and decreased intrinsic efficiency of photosystem II significantly at 14th day post treatment. Malondialdehyde, several antioxidant enzyme activities (i.e., superoxide dismutase, peroxidase and catalase), and secondary metabolites (i.e., phenolic compounds and anthocyanin) were all significantly up-regulated with 10 mg L-1NO3--N, implied oxidative stress were stimulated. However, no significant alterations in these indicators were observed with 5 mg L-1NO3--N. Compared to control, 10 mg L-1NO3--N concentration significantly stimulated microbes growth in biofilm and reduced the roughness of leaf-biofilms surface, but it had little effect on the biofilms distribution (from single clone to blocks) as revealed by scanning electron microscope and multifractal analysis. Results from X-ray photoelectron spectroscopy analysis showed that the percentage of P, Cl, K and the ratio of O1 (-O-) /O2 (C = O) were higher in leaves of control than treatments with 10 mg L-1NO3--N, indicating that 10 mg L-1NO3--N concentration exhibited significant inhibition of chemical activity and nutrient uptake of the leaf surfaces. Overall, these results demonstrated that high NO3--N does stimulate the biofilm growth and can cause negative impacts on submerged macrophytes growth.
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Affiliation(s)
- Dingxin Li
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing, 210098, China
| | - Songhe Zhang
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing, 210098, China.
| | - Tanveer M Adyel
- Department of Civil Engineering, Monash University, 23 College Walk, Clayton, VIC, 3800, Australia
| | - Kaihui Liu
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing, 210098, China
| | - Lixue Gong
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing, 210098, China
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Modeling Approach for Water-Quality Management to Control Pollution Concentration: A Case Study of Ravi River, Punjab, Pakistan. WATER 2018. [DOI: 10.3390/w10081068] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
One of the challenging problems of Punjab, the most populous province of Pakistan, is the surface water-quality problem of the Ravi River, which flows through the main cities of the province. At present, the overall status of water quality is very polluted, primarily due to residential and industrial wastewater directly discharged into the Ravi River through a network of drains. Due to the poor quality of the water, the river ecosystem is not favorable for the aquatic and surrounding environment. Hence, management options are proposed to reduce pollution. Therefore, the study was formulated to identify the main sources of pollution along the Ravi River and their potential impact on the course of the river channel. In addition, the study applied a numerical model WASP 8.1 (Water Quality Simulation Program) to discover the best strategy for the improvement of water quality. Through the model simulation it was found that, if the flow at headwater and link canals is increased up to 50%, along with 75% improvement in the pollution concentration of drains through wastewater-treatment facilities, the water quality of the Ravi River can be improved up to an acceptable limit of water-quality standards.
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