Ruđer Bošković Institute, Division for Marine and Environmental Research, Bijenička cesta 54, 10000 Zagreb, Croatia.
Institute of Oceanography and Fisheries, Šetaliste I. Meštrovića 63, 21000 Split, Croatia.
Sci Total Environ. 2020 Aug 15;730:139104. doi: 10.1016/j.scitotenv.2020.139104. Epub 2020 May 3.
The paper presents a unique time series of organic matter content (dissolved organic carbon, DOC, and its surface active substances fraction, SAS) collected in the northern Adriatic along the Po-Rovinj transect between 1998 and 2017. The data were collected on a monthly or bimonthly basis. Seasonal variance of organic matter content does not exceed 30% of its total variance, while the DOC and the SAS trends are significantly negative and positive, respectively, over the whole transect. The organic matter content, however, exhibits pronounced interannual and decadal changes, with periods of high and low carbon content and evident changes in composition of the SAS content. The changes indicate altering episodes between eutrophication and oligotrophication, embedded in the overall oligotrophication trend in the considered period. Both series were correlated with the potential local and regional yearly-averaged drivers in both atmosphere and sea. DOC is most strongly (significant at 99%) correlated with the Po River discharges, at the phase lag of -1 to -2 years. For the SAS, the largest correlations (significant at 99%) are obtained with the Adriatic-Ionian Bimodal Oscillating System index (BiOS index), at the phase lag of -3 to -4 years. Correlations between the organic matter content and the hemispheric or the regional climate indices (North Atlantic Oscillation, East Atlantic/West Russia, East Atlantic, Scandinavian, and Mediterranean Oscillation) are much lower and only sparsely significant at 95% at some phase lags. The same was found for the other local drivers (precipitation and net heat flux). Our analysis highlights the importance of remote processes, like the BiOS, that weren't previously considered to shape the biogeochemical properties of such shallow coastal region impacted by freshwater load. To properly assess such impacts, long-term ecological monitoring and homogenized data series are required.
本文呈现了一组独特的沿 1998 年至 2017 年期间的波河-罗维尼断面在亚得里亚海北部采集的有机物含量（溶解有机碳、DOC 及其表面活性物质部分、SAS）的时间序列数据。这些数据是按月或双月收集的。有机物含量的季节性变化不超过其总方差的 30%，而 DOC 和 SAS 的趋势则分别呈显著负相关和正相关，贯穿整个断面。然而，有机物含量表现出明显的年际和十年际变化，碳含量的高低期以及 SAS 含量的组成变化明显。这些变化表明，在研究期间，富营养化和寡营养化之间存在交替阶段，整体上处于寡营养化趋势中。这两个序列均与大气和海洋中的潜在局部和区域年度平均驱动因素相关。DOC 与波河流量的相关性最强（在 99%置信水平下显著），相位滞后为-1 至-2 年。对于 SAS，与亚得里亚海-爱奥尼亚双峰振荡系统指数（BiOS 指数）的相关性最大（在 99%置信水平下显著），相位滞后为-3 至-4 年。有机物含量与半球或区域气候指数（北大西洋涛动、东大西洋/俄罗斯西部、东大西洋、斯堪的纳维亚和地中海涛动）之间的相关性要低得多，只有在某些相位滞后时才稀疏地在 95%置信水平下显著。其他局部驱动因素（降水和净热通量）也是如此。我们的分析强调了远程过程的重要性，如 BiOS，这些过程以前并未被认为会影响受淡水负荷影响的此类浅海沿岸地区的生物地球化学性质。为了正确评估这些影响，需要进行长期的生态监测和均匀化数据系列。
