Related Experiment Video
Updated: Jul 12, 2026
09:10
Experimental Protocol for Biodiesel Production with Isolation of Alkenones as Coproducts from Commercial Isochrysis Algal Biomass
Published on: June 24, 2016
Arctic oceanic climate in late cenozoic time
Science (New York, N.Y.)
|August 1, 1980
Summary
Paleoceanographic events over the last 4.5 million years were reconstructed using faunal and lithologic evidence. Perennial sea-ice cover began approximately 0.7 million years ago.
Area of Science:
- Paleoceanography
- Marine Geology
- Paleoclimatology
Background:
- Understanding past oceanographic conditions is crucial for predicting future climate change.
- Reconstructing long-term oceanic and climatic shifts provides context for current environmental trends.
Purpose of the Study:
- To reconstruct paleoceanographic events over the last 4.5 million years.
- To determine the timing of key paleoceanographic shifts, such as the onset of perennial sea-ice cover.
Main Methods:
- Analysis of faunal assemblages to infer past marine conditions.
- Examination of lithologic evidence (e.g., sediment composition) to reconstruct environmental changes.
Main Results:
- Detailed reconstruction of paleoceanographic events spanning the last 4.5 million years.
- Dating the inception of perennial sea-ice cover to approximately 0.7 million years ago.
Conclusions:
- Faunal and lithologic data provide robust proxies for reconstructing past ocean environments.
- The onset of perennial sea-ice cover around 0.7 million years ago represents a significant paleoceanographic event with potential implications for global climate.
Related Concept Videos
01:16What is Climate?
Climate refers to the prevailing weather conditions in a specific area over an extended period. As the saying goes, “Climate is what you expect. Weather is what you get.” Climate is influenced by geographic factors, such as latitude, terrain, and proximity to bodies of water.
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.
02:56The Fossil Record
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
01:30Marine 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...
01:18Deep Sea Microbial Ecology
The deep ocean and its underlying sediments represent vast, largely unexplored microbial habitats that extend far beyond the sunlit photic zone. The photic (euphotic) zone typically spans the upper ~100–200 meters of pelagic waters in the open ocean, but its depth varies geographically and seasonally, where sufficient light supports photosynthetic life. Below this lies the deep sea, spanning roughly 1000–6000 meters (bathypelagic to abyssal zones), with deeper hadal trenches extending beyond...
01:27Microbes 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...