Ozone Depletion and UV Inhibition of Photosynthesis in Arctic Kelps: Spectral and Temporal Dependence

平流层臭氧的消耗，特别是在极地地区，正在引起人们对有害紫外线辐射（主要是紫外线B，280-320纳米）影响的日益关注。 UVB对许多生物过程都有损害，在植物中，特别针对光合作用。 据了解，在南极春季，由于臭氧消耗，太阳紫外线B在南大洋的穿透力大幅增加，对浮游植物的生产力产生了重大影响。这种现象在北极不太严重，但在过去三年中，与臭氧有关的紫外线B事件的增加已经加速。 该提案涉及UVB增加对大型底栖海洋大型海藻（海带）的影响以及渗入北极沿海水域的UVB水平问题。 海带光合作用对UVB的敏感性目前还知之甚少。 环境背景下的紫外线效应（280-400 nm）评估可以通过用生物加权函数（BWF;类似于作用光谱）对紫外线辐照度光谱进行加权来进行。 研究人员将测量高北极大型藻类的详细BWF和紫外线对光合作用的动力学影响，重点是海带、海带和海带。solidungula，分布在整个北极圈。 将测量在加拿大高北极地区（Resolute，79 o30 ' N; 95 oW）的两个春季和一个夏季田间季节收集的实验室培养植物和孢子体。 在为期九个月的冰雪覆盖期间，将研究暴露于不同自然光环境的植物对紫外线辐射的敏感性的差异;还将研究植物的氮状况在抵抗紫外线引起的损害的恢复过程中的重要性。研究结果将首次量化海带生境中潜在的紫外线照射，以及这种照射对北极沿海系统海带生产力的生物影响。

Depletion of stratospheric ozone, particularly in the polar regions, is causing increased concern over the effects of harmful UV radiation (mainly UVB, 280-320 nm). UVB is damaging to many biological processes, and in plants, specifically targets photosynthesis. Large increases in the penetration of solar UVB in the Southern Ocean during the austral spring from ozone depletion is known to have significant effects on phytoplankton productivity. The phenomenon is less severe in the Arctic, but ozone related increases in incident UVB have accelerated over the last three years. This proposal addresses the question of the effects of increased UVB on large benthic marine macroalgae (kelp) and the levels of UVB that penetrates into the coastal water of the Arctic. Little is known about the sensitivity of kelp photosynthesis to UVB. Assessment of UV effects (280-400 nm) in an environmental context can be made by weighting the spectrum of UV irradiance with a biological weighting function (BWF; similar to an action spectrum). The investigators will measure detailed BWF's and the kinetics of UV effects n photosynthesis of macroalgae in High Arctic, emphasizing the kelps, Laminaria saccharina and L. solidungula, which are distributed throughout the circumpolar Arctic. Both laboratory cultured plants and sporophytes collected during two spring and one summer field season in the Canadian High Arctic (Resolute, 79o30' N; 95oW) will be measured. Plants exposed to different natural light environments during the nine-month ice covered period will be examined for difference in their sensitivity to UV radiation; the importance of the nitrogen status of the plants in recovery processes that counteract UV-induced damage will also be investigated. The results will enable the first quantification of potential UV exposure in kelp habitats and the biological effects of such exposure in terms of kelp productivity in arctic coastal systems.