The present study provided the first knowledge on a broad-scale biometric distribution of the seagrass meadow (Posidonia oceanica) throughout the entire Turkish Mediterranean Sea coast. In this study, two surveys were conducted in winter and summer season of 2019, covering bottom depths range of 5–35 m to assess the growth dynamics and distribution of the P. oceanica. P. oceanica samples were collected from each sampling site by a SCUBA diver with quadrat sampling method for biometrics data. The physicochemical properties and optic characteristics of the water were also determined. Season, site, bottom type, and depth appeared to be determinative on biometric characteristics and distribution of P. oceanica. About one-third of the bottom surface area of the Turkish Mediterranean Sea coast was covered by the P. oceanica. The shoot density did not change seasonally. Leaf biomass and leaf area index were two times higher in summer compared to winter. The biometric characteristics of P. oceanica and distribution pattern differed based on the bottom type of the region. The bottom of Muğla bay is composed of sand and mud, Antalya Bay is mainly composed of rock, and Mersin Bay is mainly composed of matte and mud. Sampling season and region appeared to be determinative on biometric characters (leaf length and width, rhizome length and width or diameter, sheath length and width). The size of the meadows showed a decreasing trend with increasing depth. High variation in morphologic characters was observed in P. oceanica distributed around 15–20 m depth compared to those distributed in shallower or deeper zones. The main seasonal differences were observed in rhizome-related and leaf-related biometrics. Ecological analyses revealed that the biometric characteristics of P. oceanica were affected by season (based on changes in salinity and temperature), region (depending on bottom type), and distribution depth. In winter, the meadow was interacted with salinity, temperature and oxygen of the water. Nitrogen based-nutrients were related to the seasonal growth dynamics of the P. oceanica. The optical parameters (Sechhi depth and percent PAR, Photosynthetically Active Radiation) were not correlated with the biometrics, but the P. oceanica was found in a range of 10% to 30% of PAR. Overall, the density variables were contrasted to the morphometrical variables during the growth dynamics of the meadow. This study has presented SCUBA biometrical data which were used for in situ calibration with the corresponding acoustical echo energy of the seagrass and was an approach to use non-destructive method, the acoustical techniques.

本研究首次提供了关于整个土耳其地中海沿岸海草草甸（ Posidonia oceanica ）的大范围生物特征分布的知识。本研究在2019年冬季和夏季进行了两次调查，覆盖海底深度范围5-35 m，以评估P. oceanica的生长动态和分布。P. oceanica样本是由一名水肺潜水员采用样方抽样方法从每个采样点采集的生物特征数据。还测定了水的物理化学性质和光学特性。季节、地点、底部类型和深度似乎对大洋滨的生物特征和分布具有决定性作用。土耳其地中海沿岸约三分之一的海底面积被大洋虾覆盖。芽密度不随季节变化。夏季叶片生物量和叶面积指数是冬季的两倍。P. oceanica的生物特征和分布模式根据该地区的底部类型而有所不同。穆拉湾底部由沙和泥组成，安塔利亚湾主要由岩石组成，梅尔辛湾主要由磨砂和泥组成。采样季节和地区似乎对生物特征（叶长和宽、根茎长和宽或直径、鞘长和宽）具有决定性作用。随着深度的增加，草甸的面积呈现减小的趋势。与分布在较浅或较深区域的P. oceanica相比，分布在 15-20 m 深度附近的P. oceanica的形态特征存在很大差异。主要的季节差异是在根茎相关和叶子相关的生物特征中观察到的。生态分析表明， P. oceanica的生物特征受季节（基于盐度和温度的变化）、区域（取决于底部类型）和分布深度的影响。在冬季，草地与水的盐度、温度和氧气相互作用。氮基营养物与P. oceanica的季节性生长动态有关。光学参数（Sechhi 深度和 PAR（光合有效辐射）百分比）与生物特征无关，但 P. oceanica的 PAR 范围为 10% 至 30%。总体而言，密度变量与草地生长动态过程中的形态变量形成对比。本研究提出了水肺生物识别数据，用于利用海草相应的声学回声能量进行原位校准，是一种使用无损方法（声学技术）的方法。