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

北极海藻光合作用的臭氧消耗和紫外线抑制：光谱和时间依赖性

• 批准号: 9622483
• 负责人: Kenneth Dunton
• 金额: $ 48.97万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-06-15 至 1999-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9622483&HistoricalAwards=false
• 关键词: Ozone; Depletion; UV; Inhibition; Photosynthesis

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.

平流层臭氧的耗竭，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280-320纳米的中波紫外线）的影响的日益关注。中波紫外线对许多生物过程都是有害的，在植物中，特别针对光合作用。众所周知，在南方春季，由于臭氧耗竭，太阳中波紫外线在南大洋的穿透量大幅增加，这对浮游植物的生产力有重大影响。这种现象在北极没有那么严重，但与臭氧有关的中波紫外线的增加在过去三年中加速了。该提案解决了中波辐射增加对大型底栖海洋巨藻（海带）的影响以及渗透到北极沿海水域的中波辐射水平的问题。人们对海带光合作用对中波紫外线的敏感性知之甚少。在环境背景下评估紫外线效应（280-400 nm）可以通过使用生物加权函数（BWF，类似于作用谱）对紫外线辐照谱进行加权。研究人员将详细测量高北极地区大型藻类光合作用的BWF和动力学，重点研究分布在北极周边的海带、糖藻和L. solidungula。将测量在加拿大高纬度北极（Resolute, 79o30' N; 95oW）的两个春季和一个夏季野外季节收集的实验室培养植物和孢子体。在9个月的冰雪覆盖期间，植物暴露在不同的自然光环境下，研究它们对紫外线辐射敏感度的差异；还将研究植物在抵御紫外线损伤的恢复过程中氮状态的重要性。这些结果将使人们能够首次量化海带栖息地潜在的紫外线照射，以及这种照射对北极沿海系统海带生产力的生物影响。