隣接するアメリカにおける河川の代謝:極度の西
Taylor Maavara1,2, Zimin Yuan3, Andrew M Johnson2
1Cary Institute of Ecosystem Studies, Millbrook, NY, USA.
まとめ
河川の代謝は,総初次生産性 (GPP) と生態系の呼吸 (ER) を含め,炭素循環にとって極めて重要です. この研究は,米国の17万5千以上の川のGPPとERをモデル化し,地域の大きな変動と干ばつの影響を明らかにしています.
科学分野:
- 環境科学
- エコロジー
- 生地化学
背景:
- 河川の代謝は地球規模の炭素循環の 重要だが不確実な要素です
- 河川による炭素の流れの正確な定量化は,世界の炭素予算を理解するために不可欠です.
研究 の 目的:
- 隣接する米国 (CONUS) の17万5千以上の川の総一次生産性 (GPP) と生態系呼吸 (ER) を推定する.
- 干ばつを含む極端な水質条件に対する川の代謝反応を分析する.
主な方法:
- 大規模な河川網でGPPとERを予測するためのモデルの開発と適用
- 極端な出来事に対する代謝反応の評価のための水文学的データの統合
主要な成果:
- CONUS川の年間GPPは10.1 Tg C/年,ERは18.7 Tg C/年と予測されている.
- 河川による二酸化炭素の排出に寄与する要因は少ない.
- 河川の代謝の70%以上はアメリカ西部で発生し,ヘトロフィーとオートトロフィーの区分がある.
結論:
- 西洋の河川自給は特に乾燥した灌木地帯では干ばつに敏感である.
- これらの発見は,世界の河川による二酸化炭素の吸収が過小評価されていることを示唆しています.
- 河川の代謝を理解することは グローバルな炭素循環モデルを改良するために 極めて重要です
関連する概念動画
Rapidly Varying Flow
414
Rapidly varying flow (RVF) in open channels is characterized by abrupt changes in flow depth over a short distance, with the rate of depth change relative to distance often approaching unity. These flows are inherently complex due to their transient and multi-dimensional nature, making exact analysis difficult. However, approximate solutions using simplified models provide valuable insights into their behavior.Key Features of Rapidly Varying FlowRVF is commonly observed in scenarios involving...
414
States of Water
55.9K
Water exists in any one of the three classical states: solid (ice), liquid (water), and gas (steam or water vapor). The state of water depends on i) the intermolecular forces that draw molecules together and ii) the kinetic energy that leads to movements that pull them apart.
Water freezes when the intermolecular forces are greater than the kinetic energy. Unlike most other substances, water is less dense in its solid state than in its liquid state. This is because each water molecule can form...
Water freezes when the intermolecular forces are greater than the kinetic energy. Unlike most other substances, water is less dense in its solid state than in its liquid state. This is because each water molecule can form...
55.9K
Physiology of the Genitourinary System I: Renal Blood Flow and Glomerular Filtration
667
The kidneys are vital organs responsible for regulating blood filtration, waste excretion, and fluid balance, all of which are crucial for maintaining homeostasis. Renal physiology examines renal blood flow, glomerular filtration, and urine formation, ensuring the body’s internal environment remains stable.Renal Blood FlowThe kidneys receive about 20-25% of the cardiac output, typically around 1200 mL of blood per minute in an average adult. Blood flows into the kidneys through the renal...
667
Regulation of Water Output
2.0K
The human body predominantly expels water through the urinary system. On average, an individual generates around 1.5 liters of urine each day. This amount can fluctuate based on how well a person is hydrated, but a critical minimum quantity of urine must be produced to ensure the body's proper functioning. Daily, the kidneys remove 600 to 1200 milliosmoles of dissolved substances, effectively excreting excess minerals and water-soluble toxins such as creatinine, urea, and uric acid from the...
2.0K
Energy Considerations in Open Channel Flow
552
Open channel flow, where a fluid flows with a free surface exposed to the atmosphere, is primarily governed by gravitational and surface effects, distinguishing it from closed conduit or pipe flow. In open channels such as rivers, canals, and artificial channels, energy analysis provides valuable insights into flow behavior and the relationship between depth, velocity, and slope.Specific Energy and Flow DepthIn open channel flow, the specific energy, E, combines the gravitational potential...
552
Comparative Excretory Systems
26.4K
Animals have evolved different strategies for excretion, the removal of waste from the body. Most waste must be dissolved in water to be excreted, so an animal’s excretory strategy directly affects its water balance.
26.4K


