ホロセンの半ばの熱帯西太平洋の温度と表面海水バランス
1M. K. Gagan, L. K. Ayliffe, J. A. Cali, G. E. Mortimer, M. T. McCulloch, Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia. D. Hopley, Sir George Fisher Centre, James Cook University, Townsvil.
Science (New York, N.Y.)
|February 27, 1998
まとめ
5350年前のサンゴ礁のデータは,熱帯海面が1°C暖かく,0.5‰が酸素-18 (18O) で濃縮されていることを示しています. この温暖化により蒸発が増加し,地球規模の気候パターンに潜在的に影響し,古気候記録を調和させました.
科学分野:
- パレオセアノグラフィー
- 気候科学 気候科学
- マリン・ジオケミストリー (海洋地化学)
背景:
- 珊瑚の骨格記録は,過去の海洋状態の代理を提供している.
- 過去の海洋温度と同位体組成を理解することは,気候モデリングに不可欠です.
研究 の 目的:
- 約5350年前の熱帯海の表面状態を再現するために.
- 海洋温度と酸素同位体 (18O/16O) 濃縮の関係について調査する.
主な方法:
- 温度再構築のためのグレートバリアリーフのサンゴの骨格性ストロンチウム/カルシウム (Sr/Ca) 比率の分析.
- 珊瑚の骨格における酸素同位体 (18O/16O) の比率を測定し,海水の組成を決定する.
主要な成果:
- 熱帯海の表面温度は,現代の値より約1°C高かった.
- 海水は18Oで0.5ミリ濃度で濃縮され,蒸発が増加したことを示した.
- この18O濃縮は,熱帯外の気候に影響を及ぼし,氷河期とホロセンの18O/16Oシフトを減少させたのかもしれない.
結論:
- ホロセンの半ばの温暖化により,海洋の蒸発が増加し,18O濃縮に至った.
- この同位体異常は,過去の気候動態と脱氷の理解に意味を持つ可能性があります.
- 珊瑚の Sr/Ca と,フォラミニフェラル酸素同位体温度履歴の不一致を調和させる.
関連する概念動画
01:50Global 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.
01:11Temperature and Thermal Equilibrium
Heat and temperature are essential concepts for everyone every day. The study of heat and temperature is part of an area of physics known as thermodynamics. It is not always easy to distinguish heat and temperature.
The concept of temperature has evolved from the common concepts of hot and cold. The scientific definition of temperature explains more than just our sense of hot and cold. Temperature is operationally defined as the quantity measured with a thermometer. Furthermore, temperature is...
The concept of temperature has evolved from the common concepts of hot and cold. The scientific definition of temperature explains more than just our sense of hot and cold. Temperature is operationally defined as the quantity measured with a thermometer. Furthermore, temperature is...
01:21Isothermal Processes
A thermodynamic process that occurs at constant temperature is called an isothermal process. Heat slowly flows into the system or out of the system to maintain thermal equilibrium. Processes involving phase changes like water evaporation into steam or freezing water into ice at a constant temperature are examples of Isothermal Processes.
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
01:03Precipitation Gravimetry
Precipitation gravimetry is based on converting an analyte into a sparingly soluble precipitate, which is separated by filtration and weighed. An ideal precipitate should be pure, insoluble, of known composition, and easily filtered from the reaction mixture.
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...
01:19Body Water Content and Fluid Compartments
Life's biochemical processes occur within aqueous solutions. Solutes are substances that are dissolved within these solutions. The human body contains a variety of solutes, which can differ across various body parts. These can encompass proteins—such as those responsible for clotting and carbohydrate transport—as well as electrolytes. In medicine, an electrolyte is often described as a mineral ion derived from a salt possessing an electric charge. Examples include sodium ions (Na+) and chloride...
01:29Disorder of Water Balance
Water balance disorders are medical conditions that occur when there is a deviation from the body's water volume or osmolarity, disrupting normal homeostasis and leading todehydration, hypotonic hydration, hyperhydration, edema, or water intoxication.
Dehydration
Dehydration occurs when the body loses fluids (particularly water).
Causes:
The major causes of dehydration include excessive sweating, fever, vomiting, diarrhea, and diuresis.
Signs and Symptoms:
Symptoms primarily include intense...
Dehydration
Dehydration occurs when the body loses fluids (particularly water).
Causes:
The major causes of dehydration include excessive sweating, fever, vomiting, diarrhea, and diuresis.
Signs and Symptoms:
Symptoms primarily include intense...