氷河期と氷河期間のCO2サイクルにおける海洋生物学の役割
Karen E Kohfeld1, Corinne Le Quéré, Sandy P Harrison
1Max Planck Institute for Biogeochemistry, Jena, Germany. office@kohfeld.com
まとめ
海洋生物学的ポンプの変化は,氷河による二酸化炭素 (CO2) の排出を完全に説明できませんでした. 鉄の肥料は,氷河期に観測された二酸化炭素の減少の半分以下を占める可能性がある.
科学分野:
- パレオセアノグラフィー
- マリン・バイオジオケミストリー
- 気候科学 気候科学
背景:
- 大気中の二酸化炭素 (CO2) 濃度は,氷河期にはかなり低かった.
- 海洋生物ポンプは,大気中のCO2の重要な調節器である.
- 仮説によると,海洋生産性の変化が氷河のCO2排出量減少を促したと考えられている.
研究 の 目的:
- 氷河におけるCO2削減における海洋生物ポンプの役割を調査する.
- 鉄の受精,栄養素の利用,プランクトンの移動に関する仮説を検証する.
- 過去のCO2変化に対するこれらのメカニズムの寄与を定量化する.
主な方法:
- 海洋生産性の堆積物記録の分析.
- 最後の氷河期のピークと中期のデータを検証.
主要な成果:
- 南洋の栄養素利用の変化は,CO2の削減を説明できない.
- 支配的なプランクトン種の変化は,CO2の減少を説明するのに不十分である.
- 鉄の肥料化および関連するプロセスは,観測された氷河期CO2減少の最大50%を説明します.
結論:
- 氷河による二酸化炭素の吸収における海洋生物学的ポンプの役割は,以前から考えられていたよりも重要ではない.
- 鉄の受粉だけでは,氷河期間の大気中のCO2の減少を完全に説明することはできません.
- 他のメカニズムは,氷河期の二酸化炭素の大幅な減少に寄与した可能性がある.
さらに関連する動画
11:19Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses
Published on: October 21, 2016
13:38Laser-Induced Fluorescence Emission (L.I.F.E.) as Novel Non-Invasive Tool for In-Situ Measurements of Biomarkers in Cryospheric Habitats
Published on: October 26, 2019
関連する概念動画
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.
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 the Carbon Cycle
The carbon cycle is a fundamental Earth process involving the transfer of carbon among the biosphere, lithosphere, atmosphere, and hydrosphere. It plays a critical role in regulating the planet’s climate and supporting life by cycling carbon through various chemical forms and reservoirs. Carbon primarily circulates as carbon dioxide (CO₂), representing its oxidized form, while reduced forms such as methane (CH₄) and organic compounds also play essential roles.Microbial activity is central to...
Marine Microbial Ecology
Marine microbial ecosystems are shaped by distinct physicochemical limits, including high salinity, low nutrient availability, and fluctuating oxygen levels. These conditions favor smaller microbial cell sizes, which maximize their surface-to-volume ratio for efficient nutrient uptake.Microbial activity and community composition are closely linked to biogeochemical cycles, particularly in dynamic environments like estuaries, where halotolerant microbes thrive in response to variable salinity...
Freshwater Microbial Ecology
Freshwater systems such as streams, rivers, and lakes exhibit distinct physical and biological characteristics that influence their microbial communities. These environments are broadly categorized into lotic systems—those with flowing waters like streams and most rivers—and lentic systems, which include still or slow-moving waters such as lakes, ponds, and marshes.In lentic systems, phytoplankton drive primary production, generating autochthonous organic carbon. In contrast, lotic systems...
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...
