Reduced light is one of the primary threats to seagrass meadows in the coming decades, with reduced light reaching the benthos due to eutrophication. We assessed a multispectral photography technique using near-infrared photography to estimate chlorophyll content in the seagrass Zostera marina. Using near-infrared and red wavelength cameras in the lab environment, we measured normalized difference vegetation index (NDVI) in photographs of sampled seagrass leaves. In samples taken from three different environments, we found a positive correlation between lab-based NDVI and chlorophyll content, with variation attributable to leaf age. In samples grown under different light conditions, we found high levels of NDVI associated with lower light possibly due to seagrass photoacclimation. This method may be used in addition to existing seagrass monitoring methods to collect data on seagrass photic status and estimate chlorophyll content, and detect possible light limitation due to turbidity or high epibiota cover. The relatively low cost and time required for this method may make it useful where researchers are already collecting and imaging seagrass as part of routine monitoring.

中文翻译：

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基于实验室的多光谱摄影，用于估算大叶藻码头叶绿素含量

光照减少是未来几十年海草草甸面临的主要威胁之一，由于富营养化，到达底栖生物的光照减少。我们评估了使用近红外摄影的多光谱摄影技术来估计海草大叶藻码头中的叶绿素含量。我们在实验室环境中使用近红外和红波长相机，测量了海草叶子样本照片中的归一化植被指数（NDVI）。在取自三种不同环境的样本中，我们发现实验室 NDVI 和叶绿素含量之间呈正相关，且变化可归因于叶龄。在不同光照条件下生长的样本中，我们发现高水平的 NDVI 与较低的光照相关，可能是由于海草光驯化所致。除了现有的海草监测方法之外，还可以使用该方法来收集有关海草光状态的数据并估计叶绿素含量，并检测由于浑浊度或高表生物覆盖而可能存在的光限制。这种方法所需的成本和时间相对较低，在研究人员已经收集和成像海草作为常规监测的一部分的情况下可能会很有用。