- As water was locked up in continental ice sheets and mountain glaciers, the global sea level dropped by an estimated 120 to 130 meters (400 to 430 feet) during the last ice age, which occurred from about 2 million to 10,000 years ago.
2. Land bridges:
- With sea levels lowered, land bridges emerged connecting continents and islands. Notable land bridges included Beringia between present-day Siberia and Alaska, and the Sunda Shelf between Southeast Asia and Australia. These connections allowed for animal migrations and plant dispersals across regions that are now separated by water.
3. Coastal changes:
- As sea levels dropped, coastlines shifted dramatically, exposing once-submerged continental shelves. This had significant impacts on coastal ecosystems and human populations that relied on marine resources.
4. Ocean circulation changes:
- The massive ice sheets influenced ocean currents and circulation patterns, altering the distribution of heat energy around the globe. This, in turn, affected regional climates and could have contributed to local shifts in precipitation and temperature.
5. Salinity changes:
- As freshwater was stored in ice sheets, the remaining ocean water became slightly more saline. Changes in ocean salinity could have affected marine ecosystems and sensitive organisms, particularly in coastal and marginal environments.
6. Marine life adaptations:
- Marine life had to adapt to the changing conditions of the ice age oceans, including variations in temperature, sea level, and food availability. Many species became extinct, while others evolved adaptations that allowed them to thrive in the challenging conditions.
7. Marine sediment accumulation:
- Reduced sediment inputs from rivers due to ice cover and decreased erosion led to the accumulation of marine sediments in certain areas. This process contributed to the formation of thick sedimentary deposits that are rich in information about past environmental conditions.
