海南新村湾泰来草形态和生理指标特征及环境影响因素

海草具有重要的生态系统服务功能，其形态和生理指标受到各种环境因素的影响。本研究在2019年对海南陵水新村湾泰来草(Thalassia hemprichii)海草床进行了6次采样调查，研究了一年内1月、3月、5月、7月、9月和11月的海草形态和生理特征，分析了环境因素对泰来草形态和生理特征的影响。结果显示，泰来草形态指标叶长、叶宽、根状茎直径、根长在不同月份间存在显著差异，叶长最大值和最小值分别出现在5月[(15.05±6.13) cm]和9月[(7.19±2.55) cm]；叶宽最大值和最小值分别出现在11月[(11.93±1.68) mm]和9月[(8.73±1.96) mm]；根状茎直径最大值和最小值分别出现在11月[(5.22±1.71) mm]和3月[(4.06±0.74) mm]。泰来草地下组织碳含量在不同月份间存在显著差异，最大值和最小值分别出现在11月[(31.23±0.94)%]和3月[(24.90±3.48)%]。相关性分析显示，海水温度与泰来草叶宽、地下组织碳含量呈显著正相关；盐度与叶长和根状茎长呈显著正相关，与地下组织碳含量呈显著负相关；海水pH与叶长、叶宽、地下组织碳含量和地下组织氮含量呈显著正相关。海水中的溶解无机氮、氨氮和硝酸氮对海草生理指标有显著影响。沉积物有机碳含量与叶长、叶宽和根状茎长呈显著负相关。研究表明，新村泰来草的生长受到温度、盐度、pH的影响较大，高营养盐水平可能对泰来草产生负面影响，应该限制该地区营养盐输入。本研究可为保护新村湾泰来草海草床以及修复受损海草床生态提供数据支撑和科学依据。海南省近岸海洋生态环境过程与碳汇重点实验室 海南 三亚 572022

Characteristics of morphological and physiological indicators of Thalassia hemprichii and environmental factors in Xincun Bay, Hainan Island

Seagrasses demonstrate complex ecological functions, and their morphological and physiological indicators are affected by various environmental factors. In this study, we conducted six sampling surveys of a Thalassia hemprichii seagrass bed in Xincun Bay, Lingshui, Hainan in 2019. The morphological and physiological characteristics of seagrasses in January, March, May, July, September, and November of a single year were studied, and the effects of various environmental factors on the morphological and physiological characteristics of T. hemprichii were analyzed. The results demonstrated markedly differences in leaf length and width, rhizome length and thickness, and root length across different months. The highest value [(15.05±6.13) cm] of leaf length occurred in May, and the lowest value [(7.19±2.55) cm] in September. The highest [(11.93±1.68) mm] and the lowest [(8.73±1.96) mm] values for leaf width were recorded in November and September, respectively. The highest value [(5.22± 1.71) mm] for rhizome diameter occurred in November, and the lowest value [(4.06±0.74) mm] in March. The C content of the underground seagrass tissues was significantly different across months, with the highest value (31.23%±0.94%) in November and the lowest value (24.90%±3.48%) in March. Seawater temperature had a significantly positive correlation with leaf width and C content of the underground tissues. Salinity was significantly positively correlated with the leaf and rhizome lengths of T. hemprichii and had a negative relationship with the C content of the underground tissues. There was a significant positive correlation between pH and leaf length, leaf width, and C and N content of the underground tissues. The ammonium level in seawater was significantly positively correlated with the N content of aboveground tissues. Nitrate level of seawater was negatively correlated with the C/N ratio of the aboveground parts. There was a significant positive correlation between the dissolved inorganic nitrogen (DIN) in seawater and the N content of the underground parts. Sediment organic carbon had a negative relationship with leaf length and width, and rhizome growth. The results demonstrated that the growth of T. hemprichii in Xincun Bay was greatly affected by temperature, salinity, and pH. A high nutrient level in Xincun Bay may have a negative impact on T. hemprichii. In order to protect the T. hemprichii meadow, measures should be taken to limit the input of nutrients in Xincun Bay. The results of this study may provide data support and serve as a scientific basis for the restoration of declining seagrass.