当前位置: X-MOL 学术Geology › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Land plant evolution decreased, rather than increased, weathering rates
Geology ( IF 5.8 ) Pub Date : 2020-01-01 , DOI: 10.1130/g46776.1
Michael P. D’Antonio 1 , Daniel E. Ibarra 1 , C. Kevin Boyce 1
Affiliation  

The repeated evolution of trees is widely thought to have enhanced the capacity of silicate weathering via the impact of deep rooting. However, land plants are also responsible for wetland assembly and organic carbon burial. The total burial output of carbon via both organic and inorganic deposition must balance input to the exogenic system from volcanic outgassing on million-year time scales. Increased partitioning of carbon burial toward organic carbon and away from inorganic carbon reduces the marine carbonate burial flux, necessitating a lowered total flux of alkalinity to the oceans to maintain mass balance in the Earth’s surface carbon cycle. This flux includes the nutrient delivery from the terrestrial vegetation implicated as a driver of marine evolution, extinction, and environmental change including anoxia and black shale formation. Here, the burial of terrestrial organic carbon, first substantially in the Devonian and continuing through to the present, is argued to require a reduction in silicate weathering rates when compared to earlier times, given the independence of volcanic outgassing from weathering on short time scales. Land plants still may cause reductions in steady-state atmospheric CO2 levels, but via increasing the silicate weathering feedback strength, not silicate weathering rates. The mass-balance constraints on the long-term carbon cycle provide a mechanism for linking how land plant evolution simultaneously increased nutrient recycling and weathering efficiency of the Earth’s surface.

中文翻译:

陆地植物的进化减少而不是增加了风化率

人们普遍认为,树木的反复进化通过深生根的影响而增强了硅酸盐风化的能力。但是,陆地植物也负责湿地组装和有机碳埋葬。通过有机沉积和无机沉积产生的碳的总埋葬产出必须在百万年的时间尺度上平衡来自火山喷发的外生系统输入。碳掩埋层向有机碳和远离无机碳的分配增加,降低了海相碳酸盐埋藏通量,因此必须降低向海洋的碱度总通量,以维持地球表面碳循环中的质量平衡。这种通量包括来自陆地植被的养分输送,这是海洋演变,灭绝和环境变化(包括缺氧和黑色页岩形成)的驱动力。这里,考虑到火山岩脱气与短时间尺度上的风化无关,与早期相比,埋葬陆地有机碳(首先在泥盆纪开始并一直持续到现在)要求降低硅酸盐的风化率。陆地植物仍可能导致稳态大气中CO的减少2级,但通过增加硅酸盐风化的反馈强度,而不是硅酸盐风化率。长期碳循环的质量平衡约束条件提供了一种机制,可以联系陆地植物的进化如何同时增加地球表面的养分循环利用和风化效率。
更新日期:2019-12-18
down
wechat
bug