Characterizing Spatial Variability of Ice Algal Chlorophyll a and Net Primary Production between Sea Ice Habitats Using Horizontal Profiling Platforms
Characterizing Spatial Variability of Ice Algal Chlorophyll a and Net Primary Production between Sea Ice Habitats Using Horizontal Profiling Platforms
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DOI：
10.3389/fmars.2017.00349
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发表时间：
2017-11
影响因子：
3.7
通讯作者：
B. Lange;C. Katlein;G. Castellani;M. Fernández‐Méndez;M. Nicolaus;I. Peeken;H. Flores
中科院分区：
文献类型：
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作者：
B. Lange;C. Katlein;G. Castellani;M. Fernández‐Méndez;M. Nicolaus;I. Peeken;H. Flores
由于海冰藻类具有很强的时空变异性，评估海冰藻类生物量和初级生产力对极地生态系统的作用仍然具有挑战性。因此，海冰藻类生物量和初级生产力采样的空间代表性仍然是极地生态系统大尺度模型和气候变化预测中的一个关键问题。为了解决这个问题，我们提出了两种新的方法来放大冰藻Chla生物量和净初级生产力(Npp)的估计，该方法基于覆盖100到1000米S的剖面。这是通过将基于冰核的方法与2012年夏季在北冰洋中部进行的水平冰下光谱辐射剖面图相结合来实现的。我们对冰芯冰藻Chl a生物量与两个剖面平台进行了多尺度的比较：遥控潜水器和水面及冰下拖网(Suit)。对冰芯和远程操作运载工具调查的NPP估计进行了比较。我们的结果表明，与基于遥感载体的估计相比，基于冰核的冰藻Chla生物量和NPP的估计并不能代表性地捕捉到空间变异性，这意味着仅基于冰核观测的泛北极估计有相当大的不确定性。根据区域或冰类型对海冰核进行分组，提高了代表性。然而，由于样本量很小，获得非代表性估计的风险仍然很高。仅基于主要冰类的海冰藻类chl生物量估算结果显示，冰芯估算与遥控运载工具估算之间的一致性较好。对冰芯测量进行分组并未使npp估计值有所改善，这突显了为了得到有代表性的估计值，考虑chla生物量和底层冰光的空间变异性的重要性。对冰藻chl a生物量的基于剖面的测量发现，海冰脊是北极生态系统中被低估的组成部分，因为在这个独特的栖息地，chl a生物量要大得多。用冰芯方法不易捕捉到海冰脊，因此需要在今后的研究中给予更多关注。基于我们的研究结果，我们为设计一个高效和有效的夏季海冰藻类采样方案提供了建议。
Assessing the role of sea ice algal biomass and primary production for polar ecosystems remains challenging due to the strong spatio-temporal variability of sea ice algae. Therefore, the spatial representativeness of sea ice algal biomass and primary production sampling remains a key issue in large-scale models and climate change predictions of polar ecosystems. To address this issue, we presented two novel approaches to up-scale ice algal chl a biomass and net primary production (NPP) estimates based on profiles covering distances of 100 to 1,000 s of meters. This was accomplished by combining ice core-based methods with horizontal under-ice spectral radiation profiling conducted in the central Arctic Ocean during summer 2012. We conducted a multi-scale comparison of ice-core based ice algal chl a biomass with two profiling platforms: a remotely operated vehicle and surface and under ice trawl (SUIT). NPP estimates were compared between ice cores and remotely operated vehicle surveys. Our results showed that ice core-based estimates of ice algal chl a biomass and NPP do not representatively capture the spatial variability compared to the remotely operated vehicle-based estimates, implying considerable uncertainties for pan-Arctic estimates based on ice core observations alone. Grouping sea ice cores based on region or ice type improved the representativeness. With only a small sample size, however, a high risk of obtaining non-representative estimates remains. Sea ice algal chl a biomass estimates based on the dominant ice class alone showed a better agreement between ice core and remotely operated vehicle estimates. Grouping ice core measurements yielded no improvement in NPP estimates, highlighting the importance of accounting for the spatial variability of both the chl a biomass and bottom-ice light in order to get representative estimates. Profile-based measurements of ice algae chl a biomass identified sea ice ridges as an underappreciated component of the Arctic ecosystem because chl a biomass was significantly greater in this unique habitat. Sea ice ridges are not easily captured with ice coring methods and thus require more attention in future studies. Based on our results, we provide recommendations for designing an efficient and effective sea ice algal sampling program for the summer season.