Paleoceanography
The Once and Future Ocean
A newly collected sediment core from the Labrador Current gave Dr. Harunur Rashid a glimpse of the ancient ocean. What he saw might help inform our predictions of the future climate.
Paleoshorelines: Time capsules of the ocean’s ancient shorelines
In celebration of World Ocean’s Week, let’s take a moment to think about how far we have come in discovering the history of the oceans.
The Bipolar See-Saw: Dansgaard-Oeschger Events and the Antarctic Climate
Within large timescales of glacial and interglacial periods, mini, rapid climate shifts may occur thanks to oceanic circulation processes and balancing global ocean budgets. The events in question originate in the North Atlantic; but, how do they affect the Antarctic?
Glaciers have big league role in silica budget.
Glaciers get a lot of attention because they’re expansive sheets of ice. They’re important to understand because they can impact sea level, circulation, climate, albedo, and they are homes to microbial organisms and large animals. A new reason they are getting attention is their recently realized importance to the global silica budget. Researchers found that melting glaciers deliver enough silica to the surface ocean that their contribution should not be ignored.
Sharkcano, a melting pot for biology
No, a Sharkcano is not a volcano that erupts sharks. IT IS WAY COOLER THAN THAT! It is a submarine volcano that hosts a diverse macro community in water that is much warmer and more acidic that the surrounding seawater. Read more to find out about this alien-esc ecosystem in the South Pacific Ocean.
Mediterranean Magnetism shows Ancient Oceanic Crust
Compared to the continents, oceanic crust is relatively young, less than 200 million years. But in a corner of the Mediterranean Sea, a remnant of the ancient Neo-Tethys Ocean lurks from the time of Pangaea.
Can bumps in the seafloor explain glacial-interglacial cycles?
The best scientific theories bring lots of things together in unexpected ways. This one has ice ages, seafloor volcanoes, sea level changes, wobbles in the earth’s rotation, and much more!
Paleo-oceanography from satellite data reveal ancient tsunamis…on Mars?!
Extraplanetary tsunamis. Need I say more?
Tiny shells tell the history of Antarctic ice
Over the past 10,000 years, the West Antarctic Ice Sheet has gone through long periods of growth and long periods of retreat. Shells from the tiny organisms living in the seawater throughout the millennia can be used to reconstruct the history of times when warmer water from offshore came onto the shelf and weakened the ice shelf and what that means for the future.
The Down, Up, and Down Again of Chesapeake Bay
The Chesapeake Bay region is a densely populated area, and also experiences more rapid sea level rise than anywhere else along the North American Atlantic Coast. Why? Scientists look to the lithosphere for answers, finding that the subsidence of an ancient lithospheric bulge may be partially to blame, and will continue for millennia.
CSI Holocene: Who started the fire?
Sediment and ice cores suggest that peaks in fire activity that happened 2,500 years ago in Europe was likely caused by early humans applying the slash and burn technique to clear away forests. This demonstrates that the anthropogenic carbon footprint dates back further than the Industrial Revolution.
Balancing Act: Marine Sediments Reveal Past Carbon Cycle Fluxes
Researchers conducted a study that looks at marine sediment records to investigate sediment weathering patterns over long-term climate cycles. Somewhat surprisingly, it appears the Earth may have a mechanism for balancing variations in weathering during these glacial-interglacial cycles and mediating carbon cycle fluxes.
Path of Corrosion: How Scientists Modeled Ancient Sea-Floor Acidity
Today, we see a rapid release of CO2 to the atmosphere associated with climate change. The same was true 55 million years ago during the PETM, a time when – sediment records show – there was pervasive carbonate dissolution along the sea floor. But it was not the same pattern everywhere. Scientists attempt to model these spatial varieties and explain what occurred.
A 2.5 billion year old story about iron in the ocean, told by a rock
New light has been shed on the possibility of an alternative iron sink than previous thought prior to the oxygenation of the oceans 2.45 billion years ago. The findings could affect our interpretations of the early seawater chemistry, nutrient cycling, and trace metal distribution in the Precambrian.
Just How Permanent was El Niño in the Past?
New data refutes the hypothesis that permanent El Niño conditions existed in the tropical Pacific more than 3 million years before present, favoring climate variability more similar to modern-day.
Ironing Out the Details of the Last Ice Age
“Give me a half tanker of iron and I will give you an ice age!”, as was once said by Dr. John Martin, simplistically describes the iron hypothesis. This concept suggests that additions of iron to the ocean can ramp up biological productivity and account for some of the decreasing atmospheric carbon dioxide concentrations during the last ice age.
Rapid Reductions in North Atlantic Deep Water during the Peak of the Last Interglacial Period
North Atlantic deep water forms primarily in more extreme northern latitudes due to the colder, saltier water with a higher density. When this flow of water goes south it mixes with the cold Antarctic water and then redistributes into other parts of the world. As high latitude warming and ocean refreshing reduce water density, North Atlantic Deep Water (NADW) formation can be prohibited.
Hello Glaciers, Goodbye Winds!
With the intensification of glaciation in the northern hemisphere approximately 2.7 million years ago, the prominent westerly wind belts responded by shifting towards the equator based on evidence from sediment cores. But how exactly are scientists able to determine the position of the winds millions of years ago? The answer lies in proxies!
We didn’t start the fire!… that changed the southeast Australian landscape 44 thousand years ago
A sediment core suggests that the large ecosystem changes that occurred in southeastern Australia were caused by the extinction of large grazers, not human-controlled fire use, which caused fire-prone forest vegetation to overtake the grassy landscape.
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