云南程海真光层深度的时空分布及其影响因子

摘要

程海位于云南省丽江市永胜县, 是高原封闭型深水湖泊的典型代表.为了揭示程海真光层深度的时空分布及其影响因子, 于2016年3月-2017年2月在程海布设9个点位开展逐月调查.结果显示:光合有效辐射漫射衰减系数、真光层深度的年均值分别为1.06±0.25 m-1、4.64±1.27 m;空间变化方面, 无论"北、中、南部"还是"西、中、东部", 全年、逐月及雨旱季的真光层深度均无显著差异;时间变化方面, 5月的真光层深度最高 (6.49±1.03 m) 、7月的最低 (3.63±0.48 m), 且全年、雨季、旱季的各月份间差异显著;回归分析发现, 浮游植物生物量是程海真光层深度的最主要影响因子, 悬浮物浓度次之 (主要在雨季), 有色可溶性有机物的影响甚微.为进一步识别程海真光层深度的间接影响因子, 本文还分析了浮游植物生物量与生态因子的相关性.本研究可为程海的保护和治理积累数据并提供借鉴.%Lake Chenghai is a plateau-enclosed deep lake located in Yongsheng County, Lijiang City, Yunnan Province, China.To understand the temporal-spatial distribution of euphotic depth and its influencing factors, we carried out field investigations including nine sampling sites in the lake from March 2016 to February 2017. The results showed that the mean value of the attenuation coefficient of photosynthetically active radiation and the euphotic depth were 1.06±0.25 m-1and 4.64± 1.27 m, respectively.There were no significant difference in the spatial distribution of the euphotic depth in the whole year, months, rainy and dry seasons. Meanwhile, the euphotic depth were significantly different among months (throughout the whole year, as well as in the rainy and dry seasons), and the highest and the lowest monthly value of euphotic depth were 6.49± 1.03 m (May) and 3.63± 0.48 m (July), respectively. Moreover, the phytoplankton biomass was the main regulating factor that controlling the euphotic depth, and the impact of suspended solids on euphotic depth was found in rainy season, few impact of chromophoric dissolved organic matter on euphotic depth was detected. To further test the indirect influencing factors that affecting euphotic depth, the Spearman correlation between the phytoplankton biomass and its ecological factors was also conducted. This study could accumulate the limnological data and provide the reference for the environmental protection of Lake Chenghai.