Attenuation characteristics of photosynthetically active radiation in summer eastern LakeTaihu and implications for submerged plants restoration

?????????????????????????????????????????????????.???????????????????????????????????????3???.??2019???????????????????????????????????????????????????????????????????????????????????????????????????????????.?????????????????????????????????kd?PAR???0.73~11.80 m-1?????????????0.39~6.31 m.????????????????????????????????a????????????????????????????????CDOM??????3?????????.kd?PAR?????????????????????????a?CDOM????.????????????????????????????????????????????????a????????????????????????????????CDOM??????????????.????????????????????????????????????????????????2.7?.;The underwater light distribution is an important factor affecting aquatic ecosystems. The study on the attenuation characteristics of photosynthetically active radiation guiding significance for restoration submerged plants. In this study, based biomass data plants, eastern Lake Taihu was divided into plants sparse region, lush and no-plant region. Spatial difference in factors Taihu, dominant different regions, regime shift phases eutrophication level, relationship between euphotic depth transparency were studied by applying situ measurement August 2019. Results analyzed to provide relevant optical protection Taihu. results showed that are significantly three regions. diffuse varied from 0.73 m-1 11.80 corresponding 0.39-6.31 m. There significant differences concentrations suspended particulate inorganic matter organic concentration chlorophyll-a region higher than but not Chromophoric dissolved (CDOM) absorption coefficient had no linear fitting effect kd(PAR) with better, it worse CDOM. Water scattering main cause dominated matter, which a needs be focused ecological restoration. Suspended CDOM little attenuation. Eastern currently transition stage macrophytes-dominated state phytoplankton-dominated state, entire lake at eutrophic level. Euphotic about 2.7 times transparency.