Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0218, USA.
Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-10691 Stockholm, Sweden.
Harmful Algae. 2020 Feb;92:101739. doi: 10.1016/j.hal.2019.101739. Epub 2020 Jan 2.
Massive cyanobacteria blooms occur almost every summer in the Baltic Sea but the capability to quantitatively predict their extent and intensity is poorly developed. Here we analyse statistical relationships between multi-decadal satellite-derived time series of the frequency of cyanobacteria surface accumulations (FCA) in the central Baltic Sea Proper and a suite of environmental variables. Over the decadal scale (∼5-20 years) FCA was highly correlated (R ∼ 0.69) with a set of biogeochemical variables related to the amount of phosphorus and hypoxia in bottom layers. Water temperature in the surface layer was also positively correlated with FCA at the decadal scale. In contrast, the inter-annual variations in FCA had no correlation with the biogeochemical variables. Instead, significant correlations were found with the solar shortwave direct flux in July and the sea-surface temperature, also in July. It thus appears that it is not possible to predict inter-annual fluctuations in cyanobacteria blooms from water chemistry. Moreover, environmental variables could only explain about 45% of the inter-annual variability in FCA, probably because year-to-year variations in FCA are significantly influenced by biological interactions.
大规模的蓝藻水华几乎每年夏天都会在波罗的海发生，但定量预测其范围和强度的能力还很不完善。在这里，我们分析了波罗的海中部多十年卫星衍生的蓝藻表面聚集频率（FCA）时间序列与一系列环境变量之间的统计关系。在十年尺度上（约 5-20 年），FCA 与一系列与底层磷和缺氧量有关的生物地球化学变量高度相关（R ∼ 0.69）。表层水温也与 FCA 在十年尺度上呈正相关。相比之下，FCA 的年际变化与生物地球化学变量没有相关性。相反，在 7 月，与太阳短波直接通量和海表温度存在显著相关性。因此，似乎不可能从水化学角度预测蓝藻水华的年际波动。此外，环境变量只能解释 FCA 年际变化的约 45%，这可能是因为 FCA 的年际变化受到生物相互作用的显著影响。
