Abstract：
Crustose coralline algae (CCA) are a highly diverse group of habitat-forming, calcifying red macroalgae (Rhodophyta) with unique adaptations to diverse irradiance regimes. A distinctive CCA phenotype adaptation, which allows them to maximize photosynthetic performance in low light, is their content of a specific group of light-harvesting pigments called phycobilins. In this study, we assessed the potential of noninvasive hyperspectral imaging (HSI) in the visible spectrum (400-800 nm) to describe the phenotypic variability in phycobilin content of an Antarctic coralline, Tethysphytum antarcticum (Hapalidiales), from two distinct locations. We validated our measurements with pigment extractions and spectrophotometry analysis, in addition to DNA barcoding using the psbA marker. Targeted spectral indices were developed and correlated with phycobilin content using linear mixed models (R2 = 0.64-0.7). Once applied to the HSI, the models revealed the distinct phycoerythrin spatial distribution in the two site-specific CCA phenotypes, with thin and thick crusts, respectively. This study advances the capabilities of hyperspectral imaging as a tool to quantitatively study CCA pigmentation in relation to their phenotypic plasticity, which can be applied in laboratory studies and potentially in situ surveys using underwater hyperspectral imaging systems.
摘要：
地壳珊瑚藻（CCA）是形成栖息地的高度多样化群体，钙化红色大型藻类（Rhodophyta），对不同的辐照度方案具有独特的适应性。一种独特的CCA表型适应，这使得它们能够在弱光下最大化光合性能，是它们含有一组称为藻胆素的特定采光色素。在这项研究中,我们评估了可见光谱（400-800nm）中无创高光谱成像（HSI）的潜力，以描述南极珊瑚藻胆素含量的表型变异性，南极特氏痰（Hapalidiales），从两个不同的位置。我们通过色素提取和分光光度分析验证了我们的测量结果，除了使用psbA标记的DNA条形码。使用线性混合模型（R2=0.64-0.7）开发了目标光谱指数并将其与藻胆素含量相关。一旦应用于恒生指数，模型揭示了两种位点特异性CCA表型中不同的藻红蛋白空间分布，结壳又薄又厚，分别。这项研究提高了高光谱成像作为定量研究CCA色素沉着与其表型可塑性相关的工具的能力，这可以应用于实验室研究和潜在的现场调查使用水下高光谱成像系统。
