Strong linkage of polar cod (Boreogadus saida) to sea ice algae-produced carbon: Evidence from stomach content, fatty acid and stable isotope analyses
Strong linkage of polar cod (Boreogadus saida) to sea ice algae-produced carbon: Evidence from stomach content, fatty acid and stable isotope analyses
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极地鳕鱼（Boreogadus saida）与海冰藻类产生的碳之间存在密切联系：来自胃内容物、脂肪酸和稳定同位素分析的证据
DOI：
10.1016/j.pocean.2017.02.003
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发表时间：
2017
影响因子：
4.1
通讯作者：
H. Flores
中科院分区：
文献类型：
--
作者：
D. Kohlbach;F. Schaafsma;M. Graeve;B. Lebreton;B. Lange;C. David;M. Vortkamp;H. Flores
极地鳕鱼（Boreogadus saida）被认为是生态关键物种，因为它具有较高的生物量，并构成高北极生态系统中海鸟和海洋哺乳动物的重要碳源。年轻的极地鳕鱼（1-2 岁）通常与海冰下面有关。为了评估北极海冰栖息地变化对极地鳕鱼的影响，我们检查了极地鳕鱼的饮食组成，并量化了冰藻产生的碳（αIce）对极地鳕鱼碳预算的贡献。 2012 年夏末，在北冰洋中部的冰水界面层对幼年极地鳕鱼进行了采样。使用 4 种方法检查了这些鱼的饮食和碳源：(1) 胃内容物分析，(2) 脂肪酸 (FA) 分析，(3) 大量氮和碳稳定同位素分析 (BSIA) 和 (4) FA 的化合物特异性稳定同位素分析 (CSIA)。胃内容物的质量以冰川为主，这表明共生动物群在幼年极地鳕鱼的饮食中具有高度重要性。胃中测量的食物生物量表明每天以每条鱼体重的 1.2% 的速度持续进食，表明有积极生长的潜力。极地鳕鱼的 FA 谱表明硅藻是主要碳源，通过片足类和桡足类间接获得。使用来自肌肉的大量同位素数据的αIce估计>90%。相比之下，基于 CSIA 的 αIce 范围为 34% 至 65%，其中肌肉的估计值最高，肝组织的估计值最低。总的来说，我们的结果表明极地鳕鱼对冰藻产生的碳有很强的依赖性。这表明年轻的极地鳕鱼可能特别容易受到海冰栖息地分布和结构变化的影响。由于极地鳕鱼的生态关键作用，与海冰相关的食物网底部的变化可能会影响北极生态系统的较高营养水平。
The polar cod (Boreogadus saida) is considered an ecological key species, because it reaches high stock biomasses and constitutes an important carbon source for seabirds and marine mammals in high-Arctic ecosystems. Young polar cod (1–2 years) are often associated with the underside of sea ice. To evaluate the impact of changing Arctic sea ice habitats on polar cod, we examined the diet composition and quantified the contribution of ice algae-produced carbon (αIce) to the carbon budget of polar cod. Young polar cod were sampled in the ice-water interface layer in the central Arctic Ocean during late summer 2012. Diets and carbon sources of these fish were examined using 4 approaches: (1) stomach content analysis, (2) fatty acid (FA) analysis, (3) bulk nitrogen and carbon stable isotope analysis (BSIA) and (4) compound-specific stable isotope analysis (CSIA) of FAs.The ice-associated (sympagic) amphipodApherusa glacialisdominated the stomach contents by mass, indicating a high importance of sympagic fauna in young polar cod diets. The biomass of food measured in stomachs implied constant feeding at daily rates of ∼1.2% body mass per fish, indicating the potential for positive growth. FA profiles of polar cod indicated that diatoms were the primary carbon source, indirectly obtained via amphipods and copepods. TheαIceusing bulk isotope data from muscle was estimated to be >90%. In comparison,αIcebased on CSIA ranged from 34 to 65%, with the highest estimates from muscle and the lowest from liver tissue. Overall, our results indicate a strong dependency of polar cod on ice-algae produced carbon. This suggests that young polar cod may be particularly vulnerable to changes in the distribution and structure of sea ice habitats. Due to the ecological key role of polar cod, changes at the base of the sea ice-associated food web are likely to affect the higher trophic levels of high-Arctic ecosystems.