Seagrass and associated blue carbon ecosystems are important carbon sinks, and hence understanding their spatial and temporal variability is vital in appreciating their potential roles in climate change mitigation and adaptation. The Indo-Pacific region has the highest seagrass biodiversity, yet little focus has been made to compare seagrass habitat extent and carbon dynamics with their temperate counterparts. The present study assessed habitat characteristics and seagrass species distribution, diversity, and carbon storage in Eastern (marine) and Western (estuarine) mangrove-fringed creeks of Gazi Bay, Kenya. Data on species composition, canopy cover, biomass, and sediment organic carbon were collected in 80 plots of 0.25 × 0.25 m laid along transects established perpendicular to the waterline. Five species formation, viz., Thalassia hemprichii, Cymodocea rotundata, Cymodocea serrulata, Enhalus acoroides, and Thalassidendron ciliatum, were encountered as either single or mixed stands. There was a significant difference in total seagrass biomass between creeks (p < 0.01), with the Eastern creek recording a mean of 10.2 ± 0.6 Mg C ha–1 while the Western creek recording 4.3 ± 0.3 Mg C ha–1. In addition, sediment carbon to 1-m depth varied significantly (p < 0.01) between species in the two creeks and ranged from 98 to 302 Mg C ha–1, with the Eastern and Western creeks recording means of 258 ± 90 and 107 ± 21 Mg C ha–1, respectively. The total carbon stock from 50 ha of seagrasses in the Eastern creek was 13,420 Mg C, whereas in the 70 ha of the Western creek it was 7,769 Mg C. The study shows that seagrass community attributes such as species composition and productivity can vary dramatically over a small spatial extent due to differences in biophysical conditions and caution estimations of site-specific carbon stocks using generalized global values.

中文翻译：

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热带河口和海洋红树林边缘小溪之间海草碳储量的变化

海草和相关的蓝碳生态系统是重要的碳汇，因此了解它们的时空变异性对于理解它们在减缓和适应气候变化中的潜在作用至关重要。印度太平洋地区拥有最高的海草生物多样性，但很少有人关注将海草栖息地范围和碳动态与​​温带地区进行比较。本研究评估了肯尼亚加济湾东部（海洋）和西部（河口）红树林环绕的小溪的栖息地特征和海草物种分布、多样性和碳储存。在 80 个 0.25 × 0.25 m 的样地中收集了关于物种组成、冠层盖度、生物量和沉积物有机碳的数据，这些样地沿垂直于水线建立的横断面铺设。五种物种的形成，即 Thalassia hemprichii，Cymodocea rotundata、Cymodocea serrulata、Enhalus acoroides 和 Thalassidendron ciliatum 以单一或混杂的形式出现。小溪之间的海草总生物量存在显着差异 (p < 0.01)，东部小溪记录的平均值为 10.2 ± 0.6 Mg C ha-1，而西部小溪记录的平均值为 4.3 ± 0.3 Mg C ha-1。此外，两条小溪中不同物种之间 1 米深度的沉积物碳变化显着（p < 0.01），范围为 98 至 302 Mg C ha-1，东部和西部小溪的记录平均值为 258 ± 90 和 107 ±分别为 21 Mg C ha-1。东部小溪 50 公顷海草的总碳储量为 13,420 Mg C，而西部小溪 70 公顷的总碳储量为 7,769 Mg C。