ABSTRACT: Specific pigments produced by algae and their degradation products can provide considerable information on the taxonomic composition and photo-physiological state of algal communities. However, no previous study has looked at ice algal pigment composition in the high Arctic. We examined the bottom ice algal pigment composition in the Canadian Beaufort Sea under various snow cover conditions during the spring bloom (March to June 2008). During the early and peak bloom periods, pennate diatoms (pigment Type 2, containing chlorophyll [chl] c2 and c3) dominated the chl a biomass. Diatoms containing chl c1 (pigment Type 1) and chlorophytes were only present under high snow cover. A more diverse community was observed during the post-bloom when only low snow cover sites remained due to snow melt, with higher relative contributions of chlorophytes, prasinophytes and dinoflagellates, associated with the loss of diatoms, along with increased abundance of large empty diatoms (from microscopy) and with signs of a deteriorating physiological condition (increases in chlorophyllide a and the allomer of chl a). The ratio of photoprotective to photosynthetic pigments was generally higher at low snow cover sites, increasing seasonally with the bottom ice irradiance. Low snow cover sites differed also by having more Type 2 diatoms, increased photoprotection and greater chl a biomass during the early bloom. In addition, these sites showed increases in chl a degradation pigments that may be due to the presence of chlorophyllide-rich pennate diatoms, since the increasing biomass suggests healthy physiological conditions at that time. This study highlights the important influence of light and the light-acclimation plasticity in Arctic sea ice algae.
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机译：摘要：藻类及其降解产物产生的特定色素可以为藻类群落的生物分类和光生理状态提供大量信息。但是，以前没有研究研究北极高海拔地区的冰藻色素成分。我们在春季盛开（2008年3月至2008年6月）期间，在各种积雪条件下，检查了加拿大波弗特海的海底冰藻色素成分。在早期和高峰开花期，羽状硅藻（色素2型，含叶绿素[chl] c 2 和 c 3 < / sub>）占了chl a 生物量的主导。含有chl c 1 （颜料类型1）和叶绿素的硅藻仅在高积雪下存在。在暴风雨后，人们观察到了一个更加多样化的群落，当时由于积雪融化而仅留下了较低的积雪场所，而绿藻类，古植物和鞭毛藻的相对贡献较高，与硅藻的损失有关，而大型空硅藻的丰度增加了（显微镜检查），并显示出生理状况恶化的迹象（叶绿素 a 和chl a 的同分异构体增加）。在低雪覆盖地区，光防护色素与光合色素的比例通常较高，随底冰辐照度的增加而季节性增加。积雪量低的地方也有所不同，因为在开花初期有更多的2型硅藻，增加的光保护作用和更大的chl 生物量。此外，这些位置显示出chl 降解色素的增加，这可能是由于富含叶绿素的戊二酸酯硅藻的存在，因为生物量的增加表明当时的健康生理状况。这项研究强调了光和北极海冰藻的光适应性的重要影响。
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