Tag Archives: liviu giosan

Study Offers Economical Solutions for Maintaining Critical Delta Environments

Millions of people across the world live or depend on deltas for their livelihoods.

Formed at the lowest part of a river where its water flow slows and spreads into the sea, deltas are sediment-rich, biodiverse areas, a valuable source of seafood, fertile ground for agriculture, and host to ports important for transportation.

At least half of the deltas around the world are so-called “wave dominated deltas” – open to the sea and under the impact of wave erosion. And many more deltas will come under wave dominance as dammed rivers carry less and less sediment. In a warming climate, sea levels are rising and storms are increasing in frequency and severity, posing threats to these deltas and the people and habitats dependent on them. (more…)

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The Black Sea is a Goldmine of Ancient Genetic Data

New Study Reconstructs the Past Ocean ‘Paleome’

When Woods Hole Oceanographic Institution (WHOI) marine paleoecologist Marco Coolen was mining through vast amounts of genetic data from the Black Sea sediment record, he was amazed about the variety of past plankton species that left behind their genetic makeup (i.e., the plankton paleome).

The semi-isolated Black Sea is highly sensitive to climate driven environmental changes, and the underlying sediments represent high-resolution archives of past continental climate and concurrent hydrologic changes in the basin. The brackish Black Sea is currently receiving salty Mediterranean waters via the narrow Strait of Bosphorus as well as freshwater from rivers and via precipitation. (more…)

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Human Impact Felt on Black Sea Long Before Industrial Era

When WHOI geologist Liviu Giosan first reconstructed the history of how the Danube River built its delta, he was presented with a puzzle.

In the delta’s early stages of development, the river deposited its sediment within a protected bay. As the delta expanded onto the Black Sea shelf in the late Holocene and was exposed to greater waves and currents, rather than seeing the decline in sediment storage that he expected, Giosan found the opposite. The delta continued to grow. In fact, it has tripled its storage rate.

If an increase in river runoff was responsible for the unusual rapid build up of sediment in the delta, says Giosan, the question is, “Was this extraordinary event in the Danube delta felt in the entire Black Sea basin? And if so, what caused it?” (more…)

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Climate Change Led to Collapse of Ancient Indus Civilization, Study Finds

A new study combining the latest archaeological evidence with state-of-the-art geoscience technologies provides evidence that climate change was a key ingredient in the collapse of the great Indus or Harappan Civilization almost 4000 years ago. The study also resolves a long-standing debate over the source and fate of the Sarasvati, the sacred river of Hindu mythology.

Once extending more than 1 million square kilometers across the plains of the Indus River from the Arabian Sea to the Ganges, over what is now Pakistan, northwest India and eastern Afghanistan, the Indus civilization was the largest—but least known—of the first great urban cultures that also included Egypt and Mesopotamia. Like their contemporaries, the Harappans, named for one of their largest cities, lived next to rivers owing their livelihoods to the fertility of annually watered lands. (more…)

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Study Links Past Changes in Monsoon to Major Shifts in Indian Civilizations

A fundamental shift in the Indian monsoon has occurred over the last few millennia, from a steady humid monsoon that favored lush vegetation to extended periods of drought, reports a new study led by researchers at the Woods Hole Oceanographic Institution (WHOI). The study has implications for our understanding of the monsoon’s response to climate change.

The Indian peninsula sustains over a billion people, yet it lies at the same latitude as the Sahara Desert. Without a monsoon, most of India would be dry and uninhabitable. The ability to predict the timing and amount of the next year’s monsoon is vital, yet even our knowledge of the monsoon’s past variability remains incomplete. (more…)

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