ABSTRACT: Spatial and temporal variability characterize submerged aquatic vegetation (SAV) assemblages, but understanding the complex interactions of environmental drivers of SAV assemblages remains elusive. We documented SAV composition and biomass across a salinity gradient in a coastal estuary over 12 mo. Ten macrophyte species were identified. The dominant species, Ceratophyllum demersum and Myriophyllum spicatum, accounted for over 40% of total biomass. Only Ruppia maritima occurred across the salinity gradient. Salinity, water depth and clarity delineated 3 assemblages: a saline assemblage, and 2 groups of fresher-water species, one associated with deeper water and lower water clarity and the other associated with shallow water and higher water clarity. These assemblages exhibited intra-annual variation, with at least 5 times more biomass in late spring/mid-summer compared to early winter. This pattern was consistent across the estuary, although the difference between peak and low biomass varied by habitat type; brackish exhibited the greatest magnitude. This variation is likely due to higher variation in salinity and the species composition of this habitat. As climate change and coastal restoration impact timing and range of salinity, water depth and clarity in this region, these data can be used to help inform predictive models and management decisions.

中文翻译：

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盐度和水的清晰度决定了亚热带河口环境中沿海淹没水生植物的季节变化

摘要：时空变异表征水下水生植物（SAV）的组合，但了解SAV组合的环境驱动因素之间的复杂相互作用仍然难以捉摸。我们记录了在沿海地区超过12 mo的盐度梯度上的SAV组成和生物量。确定了十种大型植物。优势种，Ceratophyllum demersum和Myriophyllum spicatum，占总生物量的40％以上。只有马鞭草发生在整个盐度梯度上。盐度，水深和净度描绘了3种组合：盐水组合和2组淡水物种，一组与较深的水和较低的净度有关，而另一组与浅水和较高的净度有关。这些组合表现出年内变化，与初冬相比，春末/夏末生物量至少高出5倍。在整个河口，这种模式是一致的，尽管高峰和低生物量之间的差异随生境类型而变化；咸淡显示最大。这种变化可能是由于该生境的盐度和物种组成的较高变化所致。由于气候变化和沿海恢复影响该地区盐分，水深和清晰度的时间和范围，