Otero Pablo, Cabrero Águeda, Alonso-Pérez Fernando, Gago Jesús, Nogueira Enrique
Centro Oceanográfico de Vigo, Instituto Español de Oceanografía (IEO), CSIC, Subida a Radio Faro 50, 36390, Vigo, Spain.
Sci Total Environ. 2023 Nov 25;901:165791. doi: 10.1016/j.scitotenv.2023.165791. Epub 2023 Jul 30.
Thermohaline time series are crucial for detecting and quantifying abiotic changes in the marine environment, and even more so in the present global change scenario. This is particularly relevant for the Ría the Vigo and its adjacent shelf, a highly productive ecosystem at the northern limit of the Canary Current Upwelling System (CanCUS). This study analyses a 34-year time series (1987-2020) of Conductivity-Temperature-Depth (CTD) casts, the longest series available to date in the region. Long-term trends, shifts, and seasonal variability of temperature and salinity were assessed and investigated in relation to regional meteorological variability and basin-scale atmospheric teleconnection indices. Generalized Additive Models (GAM) allowed us to determine that monthly thermohaline variability can be largely explained by regional meteo-climatic variability, mainly upwelling index and river discharge. Trends and shifts in some teleconnection patterns, especially the East Atlantic (EA) pattern, may also be related to both the shift in salinity in 2013 and its long-term decrease below 50 m depth. Despite the current global warming context, no statistically significant trend was observed for either the upwelling index or temperature. The spatial analysis of sea surface temperature trends suggests that our study area has been responding to climate change differently from other surrounding near-shore areas, as the Finisterre Cape or the southern Bay of Biscay. Overall, this study highlights the importance of long-term observations to elucidate the impact of climate change in the northern limit of the CanCUS and encourages caution when extrapolating conclusions from ecosystem studies on a regional scale.
温盐时间序列对于检测和量化海洋环境中的非生物变化至关重要，在当前全球变化的背景下更是如此。这对于维哥湾及其邻近陆架尤为重要，该区域是加那利洋流上升流系统（CanCUS）北界的一个高产生态系统。本研究分析了一个长达34年（1987 - 2020年）的电导率-温度-深度（CTD）投放数据序列，这是该区域迄今为止最长的可用序列。评估并研究了温度和盐度的长期趋势、变化以及季节变异性，并将其与区域气象变异性和大尺度大气遥相关指数联系起来。广义相加模型（GAM）使我们能够确定，月度温盐变异性在很大程度上可由区域气象-气候变异性来解释，主要是上升流指数和河流流量。一些遥相关模式的趋势和变化，特别是东大西洋（EA）模式，也可能与2013年盐度的变化及其在50米深度以下的长期下降有关。尽管处于当前全球变暖的背景下，但上升流指数或温度均未观察到具有统计学意义的趋势。海表面温度趋势的空间分析表明，我们的研究区域对气候变化的响应与其他周边近岸区域不同，如菲尼斯特雷角或比斯开湾南部。总体而言，本研究强调了长期观测对于阐明CanCUS北界气候变化影响的重要性，并鼓励在从区域尺度的生态系统研究推断结论时保持谨慎。
