Ryan Ken G, McMinn Andrew, Hegseth Else N, Davy Simon K
School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, New ZealandInstitute of Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, AustraliaThe Norwegian College of Fishery Science, University of Tromsø, Tromsø N-9037, NorwaySchool of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand.
J Phycol. 2012 Feb;48(1):74-84. doi: 10.1111/j.1529-8817.2011.01104.x. Epub 2011 Dec 28.
The impacts of ultraviolet-B radiation (UVB) on polar sea-ice algal communities have not yet been demonstrated. We assess the impacts of UV on these communities using both laboratory experiments on algal isolates and by modification of the in situ spectral distribution of the under-ice irradiance. In the latter experiment, filters were attached to the upper surface of the ice so that the algae were exposed in situ to treatments of ambient levels of PAR and UV radiation, ambient radiation minus UVB, and ambient radiation minus all UV. After 16 d, significant increases in chl a and cell numbers were recorded for all treatments, but there were no significant differences among the different treatments. Bottom-ice algae exposed in vitro were considerably less tolerant to UVB than those in situ, but this tolerance improved when algae were retained within a solid block of ice. In addition, algae extracted from brine channels in the upper meter of sea ice and exposed to PAR and UVB in the laboratory were much more tolerant of high UVB doses than were any bottom-ice isolates. This finding indicates that brine algae may be better adapted to high PAR and UVB than are bottom-ice algae. The data indicate that the impact of increased levels of UVB resulting from springtime ozone depletion on Antarctic bottom-ice communities is likely to be minimal. These algae are likely protected by strong UVB attenuation by the overlying ice and snow, by other inorganic and organic substances in the ice matrix, and by algal cells closer to the surface.
紫外线B辐射（UVB）对极地海冰藻类群落的影响尚未得到证实。我们通过对藻类分离物进行实验室实验以及改变冰下辐照度的原位光谱分布，来评估紫外线对这些群落的影响。在后一项实验中，将滤光片附着在冰的上表面，以便藻类在原位接受光合有效辐射（PAR）和紫外线辐射的环境水平、去除UVB的环境辐射以及去除所有紫外线的环境辐射处理。16天后，所有处理的叶绿素a和细胞数量均显著增加，但不同处理之间没有显著差异。体外暴露的底冰藻类对UVB的耐受性远低于原位藻类，但当藻类被保留在一块坚实的冰块中时，这种耐受性会提高。此外，从海冰上层一米的卤水通道中提取并在实验室中暴露于PAR和UVB的藻类，比任何底冰分离物对高剂量UVB的耐受性都要强得多。这一发现表明，卤水藻类可能比底冰藻类更能适应高PAR和UVB环境。数据表明，春季臭氧消耗导致的UVB水平升高对南极底冰群落的影响可能很小。这些藻类可能受到上层冰雪对UVB的强烈衰减、冰基质中的其他无机和有机物质以及更接近表面的藻类细胞的保护。
