Combined effects of ultraviolet B radiation and climate warming on the biological pump: a temporal and latitudinal study

海洋中的生物循环可以简化为两个基本过程：光合作用和呼吸作用。光合作用仅发生在真光区，仅限于自养生物，而呼吸作用是整个水柱中普遍存在的过程。全球海洋规模上的这两个过程之间的平衡仍在辩论中。二氧化碳通量的变化、气候变暖和紫外线B辐射(UVBR，280-320 nm)的增加严重影响着海洋上层的光合作用和呼吸作用，目前是国际科学界关注的三个主要问题。这些因素可以协同作用于海洋浮游生物群落，从而改变表层水和深海之间的碳通量的动态。本项目审查了气候变暖、二氧化碳和紫外线BR增加对浮游生物群落的综合影响，以及由此引起的浮游系统变化将如何影响大气-海洋二氧化碳通量和水化学。该项目的独创性在于，我们提出了对关键过程-生物泵-的两极和半球间研究，共同考虑了全球重要参数对整个浮游生物群落结构和动态的影响。这项研究提案背后的特殊机会在于未来三年将发生的四个相互依存的事件的组合：(1)2005-06年从加拿大到南极洲的邮轮(并在阿根廷梅尔基奥尔站附近的南极洲过冬)乘坐51米长的加拿大钢质船体船Sedna IV，以前在极地水域工作过；(2)2007年阿根廷破冰船(Almirante Irizar)在南极洲的一次任务中可用；(3)合作研究网络(CRN)，希望得到美洲全球变化研究所(IAI)的支持，其中将包括在加拿大北极和南极洲的工作；和(4)2007年的国际极年。

Biological cycles in the ocean can be simplified to two basic processes: photosynthesis and respiration. Photosynthesis occurs exclusively in the euphotic zone and is limited  to autotrophic organisms while respiration is a ubiquitous process occurring throughout the water column. The balance between both processes on the global ocean scale is still under debate. Variation in CO2 fluxes, climate warming and increasing ultraviolet B radiation (UVBR, 280-320 nm), which strongly influence photosynthesis and respiration in the upper layer of the oceans, are presently three main concerns in the international scientific community. These factors can act synergistically on marine plankton communities, thereby modifying the dynamics of carbon fluxes between surface waters and the deep ocean. The present project examines the combined effects of climate warming, increasing CO2 and UVBR on the planktonic community and on how the resulting modifications in the planktonic system  affect atmosphere-ocean CO2 fluxes and water chemistry. The originality of this project resides in the fact that we propose a bi-polar and inter-hemispheric study of a key process -the biological pump- considering together the effects of  global significant parameters on the structure and dynamics of the whole plankton community. The special opportunity behind this research proposal resides in a combination of four inter-dependent events taking place in the next three years: (1) a cruise from Canada to Antarctica in 2005-06 (and overwintering in Antarctica in the vicinity of the Argentinean station Melchior) on board the Sedna IV, a 51m Canadian steel hull ship that has previous work experience in polar waters; (2) the availability of an Argentinean icebreaker (Almirante Irizar) for one mission in Antarctica in 2007; (3) a Cooperative Research Network (CRN) hopefully to be supported by the Inter-American Institute for Global Change Research (IAI), that would include work in the Canadian Arctic and in Antarctica; and (4) the International Polar Year (IPY) in 2007.