自从最后一个冰川最大期以来,碳循环的双重模式
H J Smith1, H Fischer, M Wahlen
1Scripps Institution of Oceanography, University of California San Diego, La Jolla 92093-0220, USA. hjsmith@aaas.org
Nature
|September 7, 2001
概括
极地冰记录揭示了与大气二氧化碳 (CO2) 显著增加相关的快速变暖事件. 这项研究分析了碳同位素,以了解全球碳循环.
科学领域:
- 古气候学 古气候学
- 气候科学 气候科学
- 地质化学 地质化学
背景情况:
- 极地冰芯提供了关于过去气候和大气组成的详细记录.
- 突发变暖事件的特征是从冰川期过渡到冰川间时期.
- 在过去的快速变暖事件中,大气中的二氧化碳度增加了80-100ppm,但原因尚不清楚.
研究的目的:
- 为了调查大气二氧化碳在过去快速气候变暖事件期间增加的原因.
- 为了分析来自南极冰核的二氧化碳的稳定碳同位素组成 (三角形CO2) 13.
- 了解不同气候模式期间全球碳循环的行为.
主要方法:
- 从南极冰块 (泰勒顶) 中被困的空气中提取二氧化碳.
- 分析稳定的碳同位素组成 (三角形13CO2).
- 全球碳循环模式的重建,从最后的冰川最大期到全新世纪.
主要成果:
- 全球碳循环在千年时间尺度上以两种不同的模式运行:一种是缓慢的气候变化,另一种是快速变暖.
- 每种模式都显示出大气,陆地和海洋之间二氧化碳交换的特征平均稳定碳同位素组成.
- 由于海面温度上升了5°C,delta 13的二氧化碳增加超过了海洋二氧化碳流量预测的数量,这表明其他因素也参与其中.
结论:
- 过去的快速气候变暖涉及全球碳循环同位素特征的明显变化.
- 在这些变暖事件中,二氧化碳增加的确切驱动因素需要进一步调查.
- 稳定碳同位素数据为地球气候系统内的复杂相互作用提供了关键的见解.
更多相关视频
09:38Single-throughput Complementary High-resolution Analytical Techniques for Characterizing Complex Natural Organic Matter Mixtures
Published on: January 7, 2019
07:32Monitoring Pedogenic Inorganic Carbon Accumulation Due to Weathering of Amended Silicate Minerals in Agricultural Soils.
Published on: June 4, 2021
相关概念视频
The Calvin Cycle
OverviewOxygenic photosynthesis plays a central role in the global carbon and oxygen cycles. The carbohydrates produced support nearly all food webs, while the oxygen by‑product enables aerobic life.Light‑dependent and light‑independent reactionsPhotosynthesis occurs in two main stages, each in a different part of the chloroplast: light‑dependent reactions and light‑independent reactions, also called the Calvin‑Benson cycle or simply the Calvin cycle.Light‑dependent reactions take place in the...
What are Biogeochemical Cycles?
The most common elements in organic molecules, carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus, are only available in the ecosystem in limited amounts. Therefore, these nutrients must be recycled through both biotic and abiotic components of the ecosystem, in processes generally called biogeochemical cycles.
The Carbon Cycle
Carbon is the basis of all organic matter on Earth, and is recycled through the ecosystem in two primary processes: one in which carbon is exchanged among living organisms, and one in which carbon is cycled over long periods of time through fossilized organic remains, weathering of rocks, and volcanic activity. Human activities, including increased agricultural practices and the burning of fossil fuels, has greatly affected the balance of the natural carbon cycle.
Global Climate Change
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
Carbon-dioxide Fixation
Carbon dioxide fixation in prokaryotes enables the assimilation of inorganic carbon into organic molecules, supporting biosynthetic pathways, sustaining ecosystems, and contributing to the global carbon cycle. It also has industrial applications in carbon capture and bioproduct synthesis. Autotrophic organisms rely on this process to utilize CO₂ as a carbon source in diverse environments.The Calvin CycleThe Calvin cycle is the most widespread carbon fixation mechanism, primarily used by...
Microbes and Climate Change
Microorganisms are pivotal agents in Earth's biogeochemical cycles, significantly influencing climate dynamics through their metabolic activities. These microbes modulate the levels of key greenhouse gases by both contributing to and helping mitigate climate change.Microbial Contributions to Greenhouse Gas EmissionsRising global temperatures accelerate microbial metabolism, which, in turn, speeds up the decomposition of organic matter. This process releases carbon dioxide (CO₂) through...
