Estimating Seagrass Community Metabolism Using Benthic Chambers: The Effect of Incubation Time
Estimating Seagrass Community Metabolism Using Benthic Chambers: The Effect of Incubation Time
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DOI：
10.1007/s12237-015-9973-z
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发表时间：
2016-01-01
影响因子：
2.7
通讯作者：
Santos, Rui
中科院分区：
文献类型：
--
作者：
Olive, Irene;Silva, Joao;Santos, Rui
海草草甸是高产的生态系统，可提供高价值的生态系统服务，并对碳固存做出重大贡献。海草草甸的净群落生产（NCP）和群落呼吸（CR）通常根据底栖室原位孵化期间氧气浓度的变化来估计。然而，孵化室会阻止水的更新，从而导致 pH 值和 O-2 增加，并导致室内可能出现过饱和，特别是在白天高辐照度下。我们使用法国科西嘉岛原始 Posidonia oceanica 草甸的底栖室测试了孵化时间对海草草甸 NCP 的影响。全天进行持续1.5-2、3-5、12和24小时的孵育。结果表明，NCP 密切遵循表盘辐照度模式，在太阳正午孵育 1.5-2 h 时获得最大 NCP 值（23.1 +/- 2.8 mmol O-2 m(-2) h(-1)）。随着孵化时间的增加，发现 NCP 预算被严重低估。与 1.5-2 小时孵化相比，3-5 小时和 12 小时孵化获得的日光 NCP 值分别低估了 NCP 24% 和 44%，而夜间孵化 12 小时则低估了 CR 63%。在估计每日预算时，与从 1.5-2 小时孵化获得的每日预算相比，根据 12 小时和 24 小时孵化（P. oceanica 中估计 NCP 最常用的孵化时间）计算的 NCP 分别低估了 19% 和 76%。还讨论了其他因素，例如室体积和封闭的生物量以及孵育时间。我们在此表明，目前文献中报道的 P. oceanica NCP 的价值可能被大大低估。因此，该社区作为地中海主要碳汇的作用可能被低估。
Seagrass meadows are highly productive ecosystems that provide high-value ecosystem services and significantly contribute to carbon sequestration. Net community production (NCP) and community respiration (CR) in seagrass meadows are usually estimated from changes in oxygen concentration during in situ incubations in benthic chambers. Nevertheless, incubation chambers prevent water renovation, thus leading to an increase in pH and O-2 and a possible super-saturation inside the chamber, particularly during daytime at high irradiances. We tested the effect of incubation time on seagrass meadows NCP using benthic chambers in a pristine Posidonia oceanica meadow in Corsica, France. Incubations lasting 1.5-2, 3-5, 12, and 24 h were conducted along the day. The results showed that NCP closely follows dial irradiance pattern, with maximum NCP values (23.1 +/- 2.8 mmol O-2 m(-2) h(-1)) obtained for 1.5-2 h incubations at solar noon. A significant underestimation of NCP budgets was detected with increasing incubation times. When compared to 1.5-2 h incubations, the daylight NCP values obtained for 3-5 h and 12 h incubations underestimated NCP by 24 and 44 %, respectively, while 12 h night incubations underestimated CR by 63 %. When daily budgets were estimated, NCP calculated from 12 and 24 h incubations, the most used incubation times to estimate NCP in P. oceanica, underestimated it by 19 and 76 %, respectively, when compared to the daily budget obtained from 1.5-2 h incubations. Other factors, such as chamber volume and enclosed biomass, in conjunction with incubation time, are also discussed. We showed here that the values of P. oceanica NCP presently reported in the literature may be considerably underestimated. The role of this community as a key carbon sink in the Mediterranean may thus be underrated.