Related Experiment Video
Updated: Jan 27, 2026
09:44
Growth and Differentiation of Adult Hippocampal Arctic Ground Squirrel Neural Stem Cells
Published on: January 7, 2011
9.9K
Limited freshwater cap in the Eocene Arctic Ocean
Lisa A Neville1,2, Stephen E Grasby3, David H McNeil1
1Geological Survey of Canada, Natural Resources Canada, Calgary, Alberta, T2L 2A7, Canada.
Scientific Reports
|March 14, 2019
Summary
The Eocene Arctic Ocean may not have had widespread freshwater caps. New evidence suggests Azolla events were linked to increased river runoff, not global freshwater layers, impacting climate models.
Area of Science:
- Paleoceanography
- Paleoclimatology
- Geology
Background:
- Eocene (~50 Ma ago) Arctic Ocean sediment records, specifically Azolla fern remains on the Lomonosov Ridge, previously suggested widespread seasonal freshwater caps.
- These caps were hypothesized to significantly impact global ocean circulation and climate.
- The Lomonosov Ridge's location during the Eocene, between the Eurasian and Amerasian Basins, raises questions about its representativeness of the entire Arctic Ocean.
Purpose of the Study:
- To test the hypothesis of extensive Eocene Arctic Ocean freshwater caps.
- To investigate the environmental conditions of the broader Arctic Ocean during the Eocene.
- To re-evaluate the impact of Azolla events on Eocene global climate and ocean circulation.
Main Methods:
- Analysis of sediment records from the western Amerasian Basin, a region distinct from the Lomonosov Ridge.
- Examination of microfauna and allochthonous organic matter associated with Azolla remains in the Amerasian Basin sediments.
Main Results:
- Azolla events in the western Amerasian Basin were found to coincide with marine microfauna and terrestrial organic matter.
- Evidence indicates Azolla occurrences were linked to an intensified hydrologic cycle, transporting terrestrial materials into the Arctic Ocean.
- Findings suggest freshwater caps, if present, were likely restricted to the smaller Eurasian Basin.
Conclusions:
- The hypothesis of widespread Eocene Arctic freshwater caps is challenged.
- Azolla events are reinterpreted as indicators of increased riverine input driven by a stronger hydrologic cycle.
- The limited extent of potential freshwater caps suggests a restricted impact on Eocene global climate, contrary to previous models.
More Related Videos
07:22Standardizing a Non-Lethal Method for Characterizing the Reproductive Status and Larval Development of Freshwater Mussels Bivalvia: Unionida
Published on: October 4, 2019
8.2K
06:16Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing
Published on: April 25, 2019
8.0K
Related Concept Videos
02:27Limiting Reactant
69.9K
The relative amounts of reactants and products represented in a balanced chemical equation are often referred to as stoichiometric amounts. However, in reality, the reactants are not always present in the stoichiometric amounts indicated by the balanced equation.
69.9K
01:29The Number e as a Limit
75
The number e is a fundamental constant in calculus, playing a central role in describing continuous change, particularly exponential growth. It is most naturally defined through its relationship with the natural logarithm, which is the inverse of the exponential function with base e. This relationship allows e to be characterized using basic principles of differentiation rather than as an arbitrary numerical constant.A key property of the natural logarithm function, ln x, is that its derivative...
75
01:14Central Limit Theorem
20.0K
The central limit theorem, abbreviated as clt, is one of the most powerful and useful ideas in all of statistics. The central limit theorem for sample means says that if you repeatedly draw samples of a given size and calculate their means, and create a histogram of those means, then the resulting histogram will tend to have an approximate normal bell shape. In other words, as sample sizes increase, the distribution of means follows the normal distribution more closely.
The sample size, n, that...
The sample size, n, that...
20.0K
01:38Limits to Natural Selection
34.4K
Organisms that are well-adapted to their environment are more likely to survive and reproduce. However, natural selection does not lead to perfectly adapted organisms. Several factors constrain natural selection.
34.4K
01:25Limits on Trigonometric Functions
59
Limits on Trigonometric FunctionsThe limits of trigonometric functions play a fundamental role in calculus, particularly in defining derivatives. One of the most important results is:which is important for differentiating trigonometric functions and is widely applied in mathematical analysis and physics.Geometric IntuitionA common approach to proving this result involves analyzing a sector of a unit circle with an angle subtended at the center. Since the arc length is numerically equal to the...
59
01:28Accuracy, limits, and approximation
1.3K
Accuracy, limits, and approximations are common in many fields, especially in engineering calculations. These concepts are imperative for ensuring that a given value is as close as possible to its true value.
Accuracy is defined as the closeness of the measured value to the true or actual value. In engineering mechanics, repeated measurements are taken during theoretical or experimental analyses to ensure that the result is precise and accurate.
The accuracy of any solution is based on the...
Accuracy is defined as the closeness of the measured value to the true or actual value. In engineering mechanics, repeated measurements are taken during theoretical or experimental analyses to ensure that the result is precise and accurate.
The accuracy of any solution is based on the...
1.3K