Carbon isotopic fractionation in macroalgae from Cádiz Bay (Southern Spain): comparison with other bio-geographic regions.
Carbon isotopic fractionation in macroalgae from Cádiz Bay (Southern Spain): comparison with other bio-geographic regions.
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DOI：
10.1016/j.ecss.2009.09.005
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发表时间：
2009-11
影响因子：
2.8
通讯作者：
J. Mercado;C. B. Santos;J. L. Pérez-Lloréns;J. Vergara
中科院分区：
文献类型：
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作者：
J. Mercado;C. B. Santos;J. L. Pérez-Lloréns;J. Vergara
为了研究溶解无机碳（DIC）的扩散与非扩散利用的扩展，并与其他生物地理区域公布的数据进行比较，对来自加的斯湾潮间带的45种大型藻类的13 C签名进行了分析。碳同位素13的值在-6.8 ‰到-33 ‰之间，但变化的范围因类群而异。因此，绿藻门的δ 13 C在− 7 ‰（松藻）到− 29.6 ‰（小柄扁藻）之间变化，而所有的褐藻（除了孔雀扁藻的δ 13 C高于− 10 ‰）都在− 10 ‰到− 20 ‰之间。在红藻门中记录到的变异范围最大，从大于− 10 ‰（粘Liagora viscida）到低于− 30 ‰的三个红藻亚纲物种。因此，计算出的红藻的δ 13 C平均值（-20.2 ‰）显著低于褐藻（-15.9 ‰）和绿色藻（-15.6 ‰）。大多数分析的红藻是栖息在裂缝和低潮间带边缘的物种，这解释了，平均而言，阴影栖息地物种的13C值低于那些生长完全暴露在阳光下（即在岩池或在上潮间带）。DIC的非扩散使用能力（即HCO3-和/或CO2的主动或促进运输）与δ 13 C值之间的比较表明，低于-30 ‰的值表明光合作用依赖于CO2的扩散进入，而高于该阈值的值则不表明非扩散DIC运输机制的必要性。此外，外部碳酸酐酶活性（extCA）和β 13 C值呈负相关，表明光合作用对HCO3 − viaextCA提供的CO2的依赖性越高，藻类材料中的β 13 C就越低。之间的比较获得的分析物种和物种栖息在其他生物地理区域（暖温带，寒冷和极地）公布的13C值表明，在全球范围内（至少为红藻和褐藻）的非扩散进入DIC是更广泛的传播之间的物种从加的斯湾比那些极地地区。如果假设DIC的非扩散性使用意味着在当今海水中CO2浓度下光合作用饱和，我们的数据表明，酸化对海藻群落光合作用的潜在影响将因纬度而异。
The13C signature of forty-five macroalgal species from intertidal zones at Cádiz Bay was analysed in order to research the extension of diffusive vs. non-diffusive utilisation of dissolved inorganic carbon (DIC) and to perform a comparison with data published for other bio-geographic regions. The ∂13C values ranged from −6.8‰ to −33‰, although the span of variation was different depending on the taxa. Thus, ∂13C for Chlorophyta varied from −7‰ (Codium adhaerens) to −29.6‰ (Flabellia petiolata), while all the Phaeophyceae (excepting Padina pavonica with ∂13C higher than −10‰) had values between −10‰, and −20‰. The widest variation range was recorded in Rhodophyta, from values above −10‰ (Liagora viscida) to values lower than −30‰ obtained in three species belonging to the subclass Rhodymeniophycidae. Accordingly, the mean ∂13C value calculated for red algae (−20.2‰) was significantly lower than that for brown (−15.9‰) and green algae (−15.6‰). Most of the analysed red algae were species inhabiting crevices and the low intertidal fringe which explains that, on average, the shaded-habitat species had a ∂13C value lower than those growing fully exposed to sun (i.e. in rockpools or at the upper intertidal zone). The comparison between the capacity for non-diffusive use of DIC (i.e. active or facilitated transport of HCO3−and/or CO2) and the ∂13C values reveals that values more negative than −30‰ indicate that photosynthesis is dependent on CO2diffusive entry, whereas values above this threshold would not indicate necessary the operation of a non-diffusive DIC transport mechanism. Furthermore, external carbonic anhydrase activity (extCA) and ∂13C values were negatively correlated indicating that the higher the dependence of the photosynthesis on the CO2supplied from HCO3−viaextCA, the lower the ∂13C in the algal material. The comparison between the ∂13C values obtained for the analysed species and those published for species inhabiting other bio-geographic areas (warm-temperate, cold and polar) suggests that globally (at least for the red and brown algae) the non-diffusive entry of DIC is more widely spread among the species from Cádiz Bay than among those of polar regions. If it is assumed that non-diffusive use of DIC implies saturation of photosynthesis at the present-day CO2concentration in seawater, our data indicate that the potential impact of the acidification on photosynthesis in the seaweed communities will be different depending on the latitude.