Metrics of the spatiotemporal variability of the physical and biological properties of Large Marine Ecosystems (LMEs) are critical indices of the trends and changes in these coastal systems. Given that the world's oceans, including coastal systems, are undergoing substantial changes as reported by a range of global assessments, the variability of these changes in space and time is important to understand, if the impacts are to be mitigated and adaptation measures required are to be appropriately applied. We have assessed the trends in Sea Surface Temperature (SST) (1982–2019) and chlorophyll-a concentrations (1997–2019) for all seven of the African LMEs. Our analysis revealed that as a whole almost 99% of all the combined area of African LMEs has warmed. We found rates of SST warming of between 0.11 °C/dec (Agulhas LME) and 0.39 °C/dec (Mediterranean Sea LME) on average for entire LMEs, and regions with rates of as high as 0.58 °C/dec in the Canary Current LME. We also found that 1.1% of the area of the LMEs had cooling trends in association with upwelling regions found in four of the seven LMEs. In this study, we have carefully considered the spatial distribution of warming and cooling in the respective LMEs and identified warming ‘hotspots’ and re-catgorized the LMEs sub-regions into ‘slow’, ‘moderate’, ‘fast’ and ‘superfast’ warming areas, as defined in the Transboundary Waters Assessment Project of the IOC-UNECO-UNEP (2016). In terms of chlorophyll-a, we report that concentration estimates are highly heterogeneous in space and time and that robust trends are, however, difficult to extract from available data. Nevertheless, we do report an overall range in chlorophyll-a concentrations of 0.06–10.9 mg/m³ and the highest median concentrations in the two Eastern Boundary Upwelling Systems, that is, the Benguela Current LME and the Canary Current LME (which also contain the regions with the highest estimates of Net Primary Production (NPP) of 7063 and 7070 mg C/m²/day, respectively). The lowest concentrations are in the oligotrophic Agulhas Current LME, which also has the lowest estimate of NPP of 342 mg C/m²/day. General declines in chlorophyll-a concentrations are observed with statistically significant rates apparent in the Agulhas LME and contrasting areas of local and patchy increases in chlorophyll-a concentrations over time. Decadal trends in NPP are assessed as generally negative in the eastern LMEs and positive in the Western LMEs. The main conclusion from this study is that while the trends themselves are a further iteration of the manifestation of climate change impacts on African LMEs, it is the high degree of heterogeneity in these properties within the LMEs, along the trans-LME distribution in some instances, that must be taken into consideration for assessment of ecosystem impacts and effective management responses.

大型海洋生态系统（LME）的物理和生物学特性的时空变化指标是这些沿海系统趋势和变化的关键指标。鉴于一系列全球评估报告指出，包括沿海系统在内的世界海洋正在发生重大变化，因此，要想减轻影响并采取必要的适应措施，就必须了解这些时空变化的可变性。适当地应用。我们评估了海表温度（SST）（1982–2019）和叶绿素a的趋势所有七个非洲LME的浓度（1997-2019年）。我们的分析表明，总体而言，非洲LME的总面积中，几乎99％都在变暖。我们发现整个LME的SST升温速率平均在0.11°C / dec（Agulhas LME）和0.39°C / dec（地中海LME）之间，在加那利，地区的SST升温速率平均在0.58°C / dec当前的LME。我们还发现，与7个LME中的4个发现的上升区相关，LME面积的1.1％具有降温趋势。在这项研究中，我们仔细考虑了各个LME的变暖和降温的空间分布，并确定了变暖的“热点”，并将LME的子区域重新分类为“慢”，“中”，“快”和“超快”。 IOC-UNECO-UNEP（2016）的跨界水域评估项目中定义的变暖区域。a，我们报告了浓度估计值在时间和空间上高度异质，但是很难从可用数据中提取出强劲的趋势。尽管如此，我们在做报告叶绿素整体范围一的0.06-10.9毫克/立方米浓度³这两个东部边界上涌的系统，也就是说，本格拉洋流LME和加纳利当前LME和最高的平均含量（其中也包含估计的最高净初级生产（NPP）最高的区域分别为7063和7070 mg C / m ² /天）。最低浓度的是贫营养的Agulhas Current LME，其最低NPP估计值也为342 mg C / m ² / day。叶绿素a普遍下降在Agulhas LME中观察到具有明显统计学意义的浓度，随着时间的流逝，叶绿素a浓度的局部和斑片状对比区域出现了明显的对比。NPP的年代际变化趋势在东部LME中总体呈阴性，而在西部LME中呈阳性。这项研究的主要结论是，尽管趋势本身是气候变化对非洲LME的影响表现的进一步迭代，但在某些情况下，这是LME内这些特性的高度异质性，以及跨LME的分布，必须在评估生态系统影响和有效的管理对策时予以考虑。