Faculty of Basic and Marine Sciences, The University of Jordan/Aqaba, PO Box 2595, Aqaba, 77110, Jordan.
Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL, 34236, USA.
Environ Monit Assess. 2020 Feb 19;192(3):188. doi: 10.1007/s10661-020-8134-4.
This research investigated physical (temperature, salinity, and density) and chemical (dissolved oxygen, ammonium, nitrate, nitrite, phosphate, and silicate) properties of offshore seawater in the Red Sea northern Gulf of Aqaba; Jordanian Site were measured during 2013-2015 to assess the temporal and seasonal variation of the upper 400 m of the water column. The study also investigated seasonal variations, assessing the relationships of temperature with physical and chemical parameters. The average value of temperature for all data was 23.03 ± 1.58 °C. Temperature followed an expected seasonal cycle during 2013-2015, with well-mixed conditions in the upper 400 m of the water column during spring (Feb-Apr) and stratification during summer (Jul-Aug). There were no significant differences among years for temperature, but highly significant differences among months and depths. The average value of salinity (psu) for all data was 40.60 ± 0.10 with significant positive or negative differences among years, months, and depths. In general, dissolved oxygen, ammonium, nitrate, nitrite, and phosphate data showed positive or negative significant differences among months and depths with no significant annual variations. Silicate only showed significant differences among depths. Correlation tests between temperature and other parameters in the upper 25 m of the water column revealed significant inverse-relationships between temperature and all other parameters (other than salinity) that were attributed to the dominant thermal controls on seawater density, to the thermodynamic controls on oxygen solubility and to seasonal increases in light irradiance that allowed nutrient consumption by primary producers. In the intermediate water column (100-150 m), similar correlations were found as in the 0-25 m data, except for silicate. In the deeper waters (300-400 m), only salinity, density, and phosphate showed significant correlations with temperature, and indicated that the seasonal effects of primary production at depth were minimal. In general, the values of all parameters during the years 2013-2015 in the upper 400 m were comparable with previous studies (e.g., 1998-2003). In conclusion, this research manifested the strong correlation of temperature with some chemical parameters and presumed seasonal controls on primary production. Given the general lack of interannual variation, water quality in the northern Gulf of Aqaba appears relatively stable.
本研究调查了红海亚喀巴湾北部外海的海水的物理性质（温度、盐度和密度）和化学性质（溶解氧、铵、硝酸盐、亚硝酸盐、磷酸盐和硅酸盐）；在 2013-2015 年期间，对 400 米以上的水柱进行了测量，以评估时间和季节变化。本研究还调查了季节变化，评估了温度与物理和化学参数的关系。所有数据的平均温度为 23.03 ± 1.58°C。在 2013-2015 年期间，温度遵循预期的季节性循环，春季（2 月至 4 月）上层 400 米的水混合良好，夏季（7 月至 8 月）分层。温度在年份之间没有显著差异，但在月份和深度之间有显著差异。所有数据的平均盐度（psu）为 40.60 ± 0.10，各年份、月份和深度之间存在显著的正或负差异。一般来说，溶解氧、铵、硝酸盐、亚硝酸盐和磷酸盐数据在月份和深度上显示出显著的正或负差异，而在年份上没有显著差异。只有硅在深度上显示出显著差异。在水柱上层 25 米处，温度与其他参数之间的相关测试显示，温度与除盐度以外的所有其他参数之间存在显著的反向关系，这归因于海水密度的主要热控制、氧气溶解度的热力学控制以及光辐照度的季节性增加，这使得初级生产者能够消耗营养物质。在中层水体（100-150 米）中，与 0-25 米数据相似的相关性也被发现，除了硅。在更深的水域（300-400 米）中，只有盐度、密度和磷酸盐与温度显示出显著的相关性，这表明深度初级生产的季节性影响最小。一般来说，2013-2015 年上层 400 米水柱中所有参数的值与以往研究（例如，1998-2003 年）相当。总之，本研究表明温度与一些化学参数之间存在很强的相关性，并假定对初级生产有季节性控制。鉴于普遍缺乏年际变化，亚喀巴湾北部的水质似乎相对稳定。
