Major role of marine vegetation on the oceanic carbon cycle
Major role of marine vegetation on the oceanic carbon cycle
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DOI：
10.5194/bg-2-1-2005
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发表时间：
2005-01-01
期刊：
影响因子：
4.9
通讯作者：
Caraco, N
中科院分区：
文献类型：
--
作者：
Duarte, CM;Middelburg, JJ;Caraco, N
在过去的海洋碳埋藏评估中，忽略了植被沉积物中的碳埋藏，使用自下而上的方法进行了评估，该方法来自于放大已发表的植被生境中碳埋藏的个人估计值汇编（海草草甸，盐沼和红树林）的影响，并在全球范围内向下的方法来自全球沉积物平衡的考虑和植被沉积物的有机碳含量的汇编。个人埋葬估计值的放大产生了111 Tmol C Y（-1）的植被栖息地的总碳埋葬。在无植被沉积物中的总埋藏量估计为126 Tg C y（-1），因此自下而上估计海洋中的总埋藏量约为244 Tg C y（-1），比目前进入全球碳预算的海洋碳埋藏量估计值高出两倍。有植物的海洋沉积物中的有机碳浓度比陆架/三角洲沉积物中的高2至10倍。自上而下重新计算海洋沉积物预算，以解释这些以前被忽视的有机物丰富的沉积物，产生自上而下的碳埋藏估计值为216 Tg C y（-1），植被沿海栖息地贡献约50%。尽管植被碳埋藏约占海洋碳埋藏总量的一半，但埋藏仅占这些生态系统净生产量的一小部分，估计约为3 388 Tg C y（-1），这表明大部分底栖生态系统净生产量必须支持其他分区（如无植被沉积物和沿海水层分区）的过量呼吸。可输出到海洋的过量有机碳总量估计在1126至3534 Tg C y（-1）之间，其中大部分必须在公海中呼吸。沿海植被生境的广泛丧失必然使海洋中的碳埋藏减少了约30 Tg Cy-1，确定这些生态系统的破坏是生物圈中CO2汇能力的重要损失。
The carbon burial in vegetated sediments, ignored in past assessments of carbon burial in the ocean, was evaluated using a bottom-up approach derived from upscaling a compilation of published individual estimates of carbon burial in vegetated habitats (seagrass meadows, salt marshes and mangrove forests) to the global level and a top-down approach derived from considerations of global sediment balance and a compilation of the organic carbon content of vegeatated sediments. Up-scaling of individual burial estimates values yielded a total carbon burial in vegetated habitats of 111 Tmol C y(-1). The total burial in unvegetated sediments was estimated to be 126 Tg C y(-1), resulting in a bottom-up estimate of total burial in the ocean of about 244 Tg C y(-1), two-fold higher than estimates of oceanic carbon burial that presently enter global carbon budgets. The organic carbon concentrations in vegetated marine sediments exceeds by 2 to 10-fold those in shelf/deltaic sediments. Top-down recalculation of ocean sediment budgets to account for these, previously neglected, organic-rich sediments, yields a top-down carbon burial estimate of 216 Tg C y(-1), with vegetated coastal habitats contributing about 50%. Even though vegetated carbon burial contributes about half of the total carbon burial in the ocean, burial represents a small fraction of the net production of these ecosystems, estimated at about 3388 Tg C y(-1), suggesting that bulk of the benthic net ecosystem production must support excess respiration in other compartments, such as unvegetated sediments and the coastal pelagic compartment. The total excess organic carbon available to be exported to the ocean is estimated at between 1126 to 3534 Tg C y(-1), the bulk of which must be respired in the open ocean. Widespread loss of vegetated coastal habitats must have reduced carbon burial in the ocean by about 30 Tg Cy-1, identifying the destruction of these ecosystems as an important loss of CO2 sink capacity in the biosphere.