UV-radiation versus grazing pressure : long-term floating of kelp rafts (Macrocystis pyrifera) is facilitated by efficient photoacclimation but und ermined by grazing losses
UV-radiation versus grazing pressure : long-term floating of kelp rafts (Macrocystis pyrifera) is facilitated by efficient photoacclimation but und ermined by grazing losses
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紫外线辐射与放牧压力：有效的光驯化促进了海带筏（Macrocystis Pyrifera）的长期漂浮，但因放牧损失而受到损害
DOI：
10.1007/s00227-010-1547-9
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发表时间：
2011
期刊：
影响因子：
2.4
通讯作者：
et al
中科院分区：
文献类型：
--
作者：
Rothaeusler Eva;Gomez Ivan;Karsten Ulf;et al
大量漂浮的大型藻类正在东南太平洋沿海水域和其他温带气候区移动。在漂浮时，这些藻类可能会暴露在全部太阳辐射下，包括 UVA 和 UVB，这可能对其生理和生长性能产生深远影响。据推测，紫外线辐射 (UVR) 的纬度变化对漂浮藻类的影响不同，低纬度地区的影响高于高纬度地区。此外，紫外线辐射和放牧可能会加速浮海藻的死亡。这一假设通过户外实验室实验进行了检验，其中巨型海藻Macrocystispyrifera(L.) C. Agardh 的孢子体暴露于不同 UVR 模式的组合（仅 PAR、PAR + UV），并在智利海岸沿线的三个地点（20°S、30°S 和 40°S）放牧。检测到辐照度的纬度趋势，其值从 40°S 到 20°S 不断增加。令人惊讶的是，漂浮的M。萤火虫在该纬度 UVR 梯度内具有高适应潜力。在 20°S 时，漂浮的海带对 UVR 稍微敏感，这反映在叶片生长减少上。在南纬30°，生理反应几乎不受当时光照的影响，但孢子体的生长和持久性主要取决于片足类食草动物的存在与否。在高纬度地区，放牧对藻类生物量和叶片生长的影响很小，海带在所有测试的环境条件下都生长良好。总的来说，我们的结果表明，floatingM.萤火虫仅受到 UVR 的轻微影响，并且孢子体可以在 20°S 至 40°S 的纬度 UVR 梯度上有效地适应。鉴于这种高适应潜力，我们认为这些（可能还有其他）积极浮力的藻类是广泛的温带纬度条件下的重要分散剂。
Large quantities of floating macroalgae are traveling in coastal waters of the SE Pacific and in other temperate climate zones. While afloat, these algae are potentially exposed to full solar radiation, including UVA and UVB, which can have profound effects on their physiological and growth performance. Latitudinal variations in UV-radiation (UVR) are hypothesized to affect floating algae differently with higher impacts at low latitudes than at high latitudes. In addition, UVR together with grazing might accelerate the demise of floating kelps. This hypothesis was tested with outdoor laboratory experiments in which sporophytes of the giant kelpMacrocystispyrifera(L.) C. Agardh were exposed to a combination of different UVR regimes (PAR only, PAR + UV) and grazing at three sites along the Chilean coast (20°S, 30°S, and 40°S). A latitudinal trend in irradiance was detected with increasing values from 40°S to 20°S. Surprisingly, floatingM. pyriferaresponded with a high acclimation potential within this latitudinal UVR gradient. At 20°S, floating kelps were slightly sensitive to UVR, which was reflected in reduced blade growth. At 30°S, physiological responses were hardly affected by the prevailing irradiance but sporophyte growth and thus persistence mainly depended on the presence or absence of amphipod grazers. At high latitudes, grazing had only minor impacts on algal biomass and blade growth, and kelps thrived well under all tested environmental conditions. Overall, our results reveal that floatingM. pyriferawas only slightly affected by UVR and that sporophytes can efficiently acclimate over a latitudinal UVR gradient that spans from 20°S to 40°S. Given this high acclimation potential, we suggest that these (and possibly other) positively buoyant algae are important dispersal agents over a wide range of temperate latitude conditions.