Resource and Environmental Management, Simon Fraser University, Burnaby, British Columbia, Canada.
Marine Protected Areas Research Group, University of Victoria, Victoria, British Columbia, Canada.
PLoS One. 2018 Jun 13;13(6):e0198348. doi: 10.1371/journal.pone.0198348. eCollection 2018.
Seagrass habitats provide important ecosystem services, including their ability to take up and store substantial amounts of organic carbon, known as 'blue carbon.' However, the paucity of geospatial and carbon storage information along the Pacific Coast of Canada hinders the inclusion of blue carbon storage data in conservation planning and policy development in coastal habitats. We assessed the carbon storage and accumulation rates in three eelgrass (Zostera marina) meadows in southern Clayoquot Sound on the Pacific Coast of British Columbia. The intertidal and subtidal portions of each meadow were mapped and sampled to estimate eelgrass density, biomass, and carbon, and sediment cores were analyzed to estimate sediment carbon storage and accumulation rates. Aboveground biomass measurements were consistent with estimates for Z. marina in other regions, with average aboveground carbon biomass estimates of 16.78 g C m-2 and 16.25 g C m-2 in the intertidal and subtidal areas, respectively. However, the estimated aboveground to belowground biomass ratio was an order of magnitude higher than for seagrass species in temperate/tropical areas, largely because belowground biomass was up to 10 times lower than for other Z. marina meadows, averaging 6.17 g C m-2 and 5.03 g C m-2 in the intertidal and subtidal zones, respectively. Sediment carbon concentrations did not exceed 1.30%Corg, and carbon accumulation rates ranged from 2.90-39.61 g Corg m-2 yr-1, decreasing with depth and averaging 10.8 ± 5.2 g Corg m-2 yr-1. While sediment carbon stocks were generally higher in the eelgrass meadows relative to non-vegetated reference sites, carbons stocks averaged 1343 ± 482 g Corg m-2, substantially less than global averages. These carbon results confirm that eelgrass does contribute to carbon storage in Clayoquot Sound but at lower rates than identified for more tropical seagrasses. By improving the quantification of site-specific carbon dynamics, eelgrass' role in climate change mitigation and conservation planning can be assessed.
海草生境提供了重要的生态系统服务，包括其吸收和储存大量有机碳的能力，这些有机碳被称为“蓝碳”。然而，加拿大太平洋沿岸地区缺乏地理空间和碳储存信息，这阻碍了将蓝碳储存数据纳入沿海生境的保护规划和政策制定。我们评估了不列颠哥伦比亚省南部克拉阔特湾太平洋沿岸三个鳗草（Zostera marina）草地的碳储存和积累速率。每个草地的潮间带和亚潮带部分都进行了测绘和采样，以估算鳗草的密度、生物量和碳，同时还分析了沉积物岩芯，以估算沉积物碳储存和积累速率。地上生物量测量结果与其他地区的 Z. marina 估计值一致，潮间带和亚潮带的平均地上碳生物量估计值分别为 16.78 g C m-2 和 16.25 g C m-2。然而，估计的地上与地下生物量比值比温带/热带地区的海草物种高一个数量级，主要是因为地下生物量低了一个数量级，潮间带和亚潮带的地下生物量平均值分别为 6.17 g C m-2 和 5.03 g C m-2。沉积物碳浓度不超过 1.30%Corg，碳积累速率范围为 2.90-39.61 g Corg m-2 yr-1，随深度降低，平均值为 10.8 ± 5.2 g Corg m-2 yr-1。虽然相对于无植被参考点，鳗草草地中的沉积物碳储量通常更高，但碳储量平均为 1343 ± 482 g Corg m-2，远低于全球平均值。这些碳结果证实，鳗草确实有助于克拉阔特湾的碳储存，但积累速率低于更热带的海草。通过提高对特定地点碳动态的量化，可评估鳗草在气候变化缓解和保护规划中的作用。
