Data from: Sensitivity and acclimation of three canopy-forming seaweeds to UVB radiation and warming

Canopy-forming seaweeds, as primary producers and foundation species,
provide key ecological services. Their responses to multiple stressors
associated with climate change could therefore have important knock-on
effects on the functioning of coastal ecosystems. We examined interactive
effects of UVB radiation and warming on juveniles of three habitat-forming
subtidal seaweeds from Western Australia–Ecklonia radiata, Scytothalia
dorycarpa and Sargassum sp. Fronds were incubated for 14 days at 16–30°C
with or without UVB radiation and growth, health status, photosynthetic
performance, and light absorbance measured. Furthermore, we used empirical
models from the metabolic theory of ecology to evaluate the sensitivity of
these important seaweeds to ocean warming. Results indicated that
responses to UVB and warming were species specific, with Sargassum showing
highest tolerance to a broad range of temperatures. Scytothalia was most
sensitive to elevated temperature based on the reduced maximum quantum
yields of PSII; however, Ecklonia was most sensitive, according to the
comparison of activation energy calculated from Arrhenius’ model. UVB
radiation caused reduction in the growth, physiological responses and
thallus health in all three species. Our findings indicate that
Scytothalia was capable of acclimating in response to UVB and increasing
its light absorption efficiency in the UV bands, probably by up-regulating
synthesis of photoprotective compounds. The other two species did not
acclimate over the two weeks of exposure to UVB. Overall, UVB and warming
would severely inhibit the growth and photosynthesis of these
canopy-forming seaweeds and decrease their coverage. Differences in the
sensitivity and acclimation of major seaweed species to temperature and
UVB may alter the balance between species in future seaweed communities
under climate change.

冠层形成海藻作为初级生产者（primary producers）和基础物种（foundation species），提供关键的生态服务（ecological services）。因此，它们对气候变化相关多重胁迫因子（multiple stressors）的响应，可能对海岸生态系统（coastal ecosystems）的功能产生重要连锁效应（knock-on effects）。

我们研究了UVB辐射（UVB radiation）与升温（warming）对西澳大利亚三种形成栖息地的潮下带海藻幼体的交互作用（interactive effects）——Ecklonia radiata、Scytothalia dorycarpa及Sargassum sp.。藻叶在16–30°C条件下培养14天，设置有无UVB辐射处理组，并测定其生长、健康状态（health status）、光合性能（photosynthetic performance）及光吸收（light absorbance）情况。

此外，我们利用生态代谢理论（metabolic theory of ecology）中的经验模型（empirical models），评估了这些重要海藻对海洋升温（ocean warming）的敏感性（sensitivity）。结果表明，对UVB辐射和升温的响应具有物种特异性（species specific），其中马尾藻属（Sargassum sp.）对广泛温度范围表现出最高耐受性（tolerance）。基于PSII最大量子产率（maximum quantum yields of PSII）的降低，Scytothalia对升温最为敏感；然而，根据阿伦尼乌斯模型（Arrhenius’ model）计算的活化能（activation energy）比较结果，Ecklonia则最为敏感。

UVB辐射导致所有三种海藻的生长、生理响应（physiological responses）及藻体健康（thallus health）均出现下降。我们的研究结果表明，Scytothalia能够通过上调光保护化合物（photoprotective compounds）的合成，对UVB产生适应性反应（acclimating）并提高其在UV波段（UV bands）的光吸收效率（light absorption efficiency）。另外两种物种在两周的UVB暴露期间未表现出适应性。

总体而言，UVB和升温将严重抑制这些冠层形成海藻的生长与光合作用（photosynthesis），并降低其覆盖度（coverage）。主要海藻物种对温度和UVB的敏感性及适应性（acclimation）差异，可能会改变气候变化下未来海藻群落（seaweed communities）的物种平衡（balance between species）。