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。光合作用只发生在光区，仅限于自养生物，而呼吸作用则是在整个水体中普遍存在的过程。这两个过程在全球海洋尺度上的平衡仍在争论中。二氧化碳通量的变化、气候变暖和紫外线B辐射（UVBR, 280-320 nm）的增加强烈影响海洋上层的光合作用和呼吸作用，这是目前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动态。目前的项目考察了气候变暖、二氧化碳增加和UVBR对浮游生物群落的综合影响，以及浮游生物系统中由此产生的变化如何影响大气-海洋二氧化碳通量和水化学。这个项目的独创性在于，我们提出了一个关键过程的双极和半球间研究——生物泵——同时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。这项研究计划背后的特殊机会存在于未来三年发生的四个相互依赖的事件的组合中：(1)2005- 2006年从加拿大到南极洲的巡航（并在南极洲阿根廷Melchior站附近越冬），乘坐一艘51米长的加拿大钢壳船Sedna IV，该船以前在极地水域工作过；(2)阿根廷破冰船（Almirante Irizar）能否在2007年在南极洲执行一次任务；(3)一个合作研究网络（CRN），希望得到美洲全球变化研究所（IAI）的支持，这将包括在加拿大北极和南极洲的工作；(4) 2007年的国际极地年（IPY）。

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.