SEA LEVEL
And human history
Sea level changes over the course of history have had an immense impact on coastal geography. Because of this, determining the shape of ancient coastlines has helped explain how early modern humans came to inhabit areas of the world that are now separated by oceans.
Beringia
Thousands of years ago, North America and Asia were connected via the Beringia land bridge, which spanned the North Pacific between what is today called Russia and Alaska. This land bridge, now lying far beneath the cold Bering Strait, is a site that is considered pivotal to the early migration of humans from east Asia to North America.
It was thought for a long time that stone-age hunters most likely the land bridge on foot 13,000 years ago, but there has been substantial evidence in recent years to counteract this theory.
This animated GIF shows sea levels (in meters) rising over the last 21,000 years in the Beringia region - the location of the modern Bering Strait.
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When dissolved in water, CO2 becomes carbonic acid. Carbonic acid is a natural component of seawater, but increased carbon emissions due to industrialization have caused the levels of carbonic acid in seawater to increase significantly over time. The natural, alkaline pH of the ocean is something that marine life has adapted to over millions of years; as the pH decreases, ocean conditions become increasingly hostile to marine organisms that are not adapted to survive them. In one laboratory trial simulating the projected ocean conditions in the year 2100, the shell of a pteropod (a small marine mollusc) dissolved almost entirely over the course of 45 days. (See above)
While this sounds like quite a scary situation, there have been many solutions proposed to combat ocean acidification - for instance, the planting of seaweed. A group working in partnership with an oyster hatchery in California found that growing plots of native red seaweed helped to moderate carbon and nitrogen levels in the local area.
While this sounds like quite a scary situation, there have been many solutions proposed to combat ocean acidification - for instance, the planting of seaweed. A group working in partnership with an oyster hatchery in California found that growing plots of native red seaweed helped to moderate carbon and nitrogen levels in the local area.