Scientists recently discovered a giant hidden pool of freshwater sitting offshore New England. The freshwater extends from Delaware to Massachusetts and has sat undisturbed since the last Ice Age.
Approximately 26,500 years ago Earth was covered in ice sheets. This was the Last Glacial Maximum (LGM), the largest extent of glaciation during the most previous Ice Age. At that point, much of the northern portion of the United States was covered in vast ice sheets.
Since then, Earth has slowly warmed and with it created the Great Lakes and many other smaller lakes dotting the northern portion of our country.
But what does this have to do with a sea of freshwater hidden off New England? If you can picture the last ice age, since so much ice was on top of continents in the form of ice sheets, sea level was significantly lower. Sea level was as low as 400 feet below current sea level during the last ice age. During that time, the coastlines were extended out much farther than today, exposing the continental shelf as land transitions to the ocean.
That area, which was above water and is now under the ocean was covered in ice as well during the last ice age. When the ice sheets began to melt on the coast of New England the freshwater seeped into the continental shelf and created a massive pool of freshwater. Gradually, that land was covered with rising sea level and now lies sitting beneath the ocean.
The existence of freshwater beneath the ocean in New England was initially discovered as oil companies drilled pilot holes in the offshore and hit freshwater. However, the wells are mere pinpricks in the vast continental shelf and scientists weren't sure how extensive the freshwater was offshore.
Recently, scientists from Columbia University's Lamont-Doherty Earth Observatory published their research on the topic in the journal Scientific Reports. The research team used electromagnetic sensors towed behind a research ship to measure the difference in conductivity in the water below. Salt water is much more conductive than freshwater and thus the research team was looking for areas of low conductance.
They found pools of fresh and semi-brackish water extending from Delaware to Massachusettes and possibly further north. The sum total is believed to be twice the volume of Lake Ontario and stretches for hundreds of miles.
While New England is fortunate enough to have ample rain and freshwater lakes nearby, this finding could point to potential offshore freshwater pools in other parts of the country or world. In arid places such as California and the Middle East, the existence of an offshore reservoir of freshwater could be a lifeline for the people living in these areas. Continued research and testing offshore arid coasts will help to determine if similar scenarios exist elsewhere and how they may be used in the future for freshwater.
