北極海の西部の土着の溶けた有機炭素の分解
Dennis A Hansell1, David Kadko, Nicholas R Bates
1Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA. dhansell@rsmas.miami.edu
まとめ
川は海に溶けた有機炭素を大量に放出しています. この研究は,北極海における土生地溶解有機炭素の分解がゆっくりと,半減期が7.1年で,その輸出に影響を及ぼすことを明らかにしています.
科学分野:
- 海洋学 海洋学 海洋学
- バイオジオケミストリー バイオジオケミストリー
- 炭素循環は,炭素の循環というものです.
背景:
- 河川は,大洋に流入する原生有機炭素の主要な経路である.
- 海洋環境における溶解した有機炭素の最終的な運命と除去メカニズムは,依然としてほとんど不明である.
- 以前の研究は,大陸棚の上で保守的な行動を示唆し,海底の深い海で長い時間スケールで除去が起こります.
研究 の 目的:
- 地元の溶解有機炭素 (TDOC) の分解と除去プロセスを調査する.
- 北極海の西部のTDOCの鉱化率を定量化するために.
- 北極から北大西洋までのTDOCの輸出効率を決定する.
主な方法:
- ボフォート・ジューリにおけるTDOC濃度グラデーションの分析.
- 同位体トレーサーを用いて,水質の年齢を決定する.
- 年齢と濃度データを基に鉱化半減期を計算する.
主要な成果:
- TDOCは,ボーフォート・ギュアでゆっくりと劣化しています.
- TDOCの鉱化半減期は7.1 ±3.0年であると決定されました.
- TDOCの21~32%しか北大西洋に輸出されていないと推定されています.
結論:
- 陸生溶解有機炭素は,北極海内で著しい鉱化が行われている.
- 劣化速度が遅いことから,TDOCの大部分は輸出前に消費されていることがわかります.
- この発見は,世界の炭素予算と海洋の栄養循環を理解する上で重要な意味を持つ.
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.
Overview of Nitrogen Metabolism
Nitrogen is a very important element for life because it is a major constituent of proteins and nucleic acids. It is a macronutrient, and in nature, it is recycled from organic compounds and stored in the form of ammonia, ammonium ions, nitrate, nitrite, or nitrogen gas by many metabolic processes. Many of these metabolic processes are carried out only by prokaryotes.
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
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...
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...


