Githaiga Michael N, Kairo James G, Gilpin Linda, Huxham Mark
Kenya Marine and Fisheries Research Institute, Mombasa, Kenya.
School of Applied Sciences, Edinburgh Napier University, Edinburgh, United Kingdom.
PLoS One. 2017 May 10;12(5):e0177001. doi: 10.1371/journal.pone.0177001. eCollection 2017.
Vegetated marine habitats are globally important carbon sinks, making a significant contribution towards mitigating climate change, and they provide a wide range of other ecosystem services. However, large gaps in knowledge remain, particularly for seagrass meadows in Africa. The present study estimated biomass and sediment organic carbon (Corg) stocks of four dominant seagrass species in Gazi Bay, Kenya. It compared sediment Corg between seagrass areas in vegetated and un-vegetated 'controls', using the naturally patchy occurence of seagrass at this site to test the impacts of seagrass growth on sediment Corg. It also explored relationships between the sediment and above-ground Corg, as well as between the total biomass and above-ground parameters. Sediment Corg was significantly different between species, range: 160.7-233.8 Mg C ha-1 (compared to the global range of 115.3 to 829.2 Mg C ha-1). Vegetated areas in all species had significantly higher sediment Corg compared with un-vegetated controls; the presence of seagrass increased Corg by 4-6 times. Biomass carbon differed significantly between species with means ranging between 4.8-7.1 Mg C ha-1 compared to the global range of 2.5-7.3 Mg C ha-1. To our knowledge, these are among the first results on seagrass sediment Corg to be reported from African seagrass beds; and contribute towards our understanding of the role of seagrass in global carbon dynamics.
植被丰富的海洋栖息地是全球重要的碳汇，对缓解气候变化做出了重大贡献，并且它们还提供了广泛的其他生态系统服务。然而，知识方面仍存在很大差距，尤其是对于非洲的海草草甸。本研究估算了肯尼亚加齐湾四种主要海草物种的生物量和沉积物有机碳（Corg）储量。利用该地点海草自然分布不均的情况，比较了有植被和无植被“对照”的海草区域之间的沉积物Corg，以测试海草生长对沉积物Corg的影响。研究还探讨了沉积物与地上Corg之间的关系，以及总生物量与地上参数之间的关系。不同物种之间的沉积物Corg存在显著差异，范围为160.7 - 233.8 Mg C ha-1（相比全球范围为115.3至829.2 Mg C ha-1）。与无植被的对照相比，所有物种的植被区域的沉积物Corg均显著更高；海草的存在使Corg增加了4至6倍。不同物种之间的生物量碳存在显著差异，平均值在4.8 - 7.1 Mg C ha-1之间，而全球范围为2.5 - 7.3 Mg C ha-1。据我们所知，这些是非洲海草床首次报道的有关海草沉积物Corg的结果之一；有助于我们了解海草在全球碳动态中的作用。
