Implications of Glacial Melt-Related Processes on the Potential Primary Production of a Microphytobenthic Community in Potter Cove (Antarctica)
Implications of Glacial Melt-Related Processes on the Potential Primary Production of a Microphytobenthic Community in Potter Cove (Antarctica)
复制标题
DOI：
10.3389/fmars.2019.00655
复制
发表时间：
2019-10-29
影响因子：
3.7
通讯作者：
Braeckman, Ulrike
中科院分区：
文献类型：
--
作者：
Hoffmann, Ralf;Al-Handal, Adil Yousif;Braeckman, Ulrike
南极半岛的冰川迅速消退，导致颗粒释放和沉积增加，从而减少了可用于底栖生物初级生产的光合有效辐射（PAR，400-700 nm）。在这项研究中，我们调查了一般的沉积和阴影模式的变化如何影响底栖微藻的初级生产力。为了确定微型底栖植物群落的潜在净初级生产力和呼吸作用，将来自不同沉积速率和遮光条件下的沉积物柱芯暴露于0-70 μ mol photons m（-2）s（-1）的PAR。总氧交换率和microphytobenthic硅藻群落结构，密度和生物量进行了测定。我们的研究表明，虽然微型底栖硅藻的密度和组成保持相似，但微型底栖硅藻的净初级生产力随着沉积和遮荫的增加而下降。通过比较我们的实验结果与现场测量的PAR强度，我们进一步确定了微型植物底栖初级生产力作为一个重要的碳源在波特湾的底栖生态系统。我们建议，microphytobenthic总初级生产力的贡献可能会大幅下降，由于南极冰川退缩和相关的沉积和阴影，但未知的后果，底栖异养群落，其结构和多样性。
The Antarctic Peninsula experiences a fast retreat of glaciers, which results in an increased release of particles and sedimentation and, thus, a decrease in the available photosynthetic active radiation (PAR, 400-700 nm) for benthic primary production. In this study, we investigated how changes in the general sedimentation and shading patterns affect the primary production by benthic microalgae, the microphytobenthos. In order to determine potential net primary production and respiration of the microphytobenthic community, sediment cores from locations exposed to different sedimentation rates and shading were exposed to PAR of 0-70 mu.mol photons m(-2)s(-1). Total oxygen exchange rates and microphytobenthic diatom community structure, density, and biomass were determined. Our study revealed that while the microphytobenthic diatom density and composition remained similar, the net primary production of the microphytobenthos decreased with increasing sedimentation and shading. By comparing our experimental results with in situ measured PAR intensities, we furthermore identified microphytobenthic primary production as an important carbon source within Potter Cove's benthic ecosystem. We propose that the microphytobenthic contribution to the total primary production may drop drastically due to Antarctic glacial retreat and related sedimentation and shading, with yet unknown consequences for the benthic heterotrophic community, its structure, and diversity.