Aquatic Science

1. Aquatic Science Fossil Aquifers and Marshes

2. What is a Fossil Aquifer • It is ground water that has remained sealed in an aquifer for a long period of time. • The water contained in the aquifers cannot be replenished and may have been locked in for thousands of years. • Water in these aquifers can be referred to as fossil water or Paleowater. • The age of the water is what gives it the name “fossil water”.

3. Problems with Water Quality • Fossil water aquifers can be brackish or salt water. • They can be contaminated. • Fossil aquifers can also be highly radioactive depending on the surrounding geology

4. Non-Renewable Resource • Fossil aquifers are non-renewable resources. • Changes in the surrounding geology have sealed the aquifer from precipitation “trapping” the water. • Water in these aquifers is stagnant, and has little if any flow.

5. Fossil Water Resources • Most often found in arid climates, fossil and other non-renewable aquifers are an important water resource for many nations. • Fossil water resources will eventually run out once they begin being used.

6. Some Countries Rely on Fossil Aquifers • For over 50 years Libya has relied on fossil water supplies that are now dwindling. • India, China, and Mexico all depend on non-renewable water taken from ancient aquifers.

7. The United States • In the United States a number of the Great Plains states take a considerable amount of their water from a fossil water aquifer. • This water reservoir is the Ogallala Aquifer or the high planes Aquifer. • Estimates forecast this aquifer being empty in 25 years. • The disruption is likely to be immense as the aquifer covers portions of eight states, and supplies 82% of the drinking water for these states and around 30% of the water used for crop irrigation in the area.

8. What Are Marshes? • Marshes are defined as wetlands frequently or continually inundated with water. • Marshes recharge groundwater supplies and moderate streamflow by providing water to streams. • Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, and moss.

9. Brackish Water Marshes • Brackish marshes are transitional between freshwater and salt marsh communities. • Brackishmarshes are found on the edges of soundsand estuaries.  • Sound: A long body of water between an island and the mainland. Northern Water Snake

10. Brackish Zone • The brackish zone is where the fresh rivers meet the salty ocean. • Water from rivers dilute the saltwater. • Water in brackish marshes rises and falls with the tides.

11. Brackish Marsh Plants • Plants that live in a brackish marsh depend on how salty the water is. • Saltier brackish marshes have Black Needlerush (Juncusroemerianus) and Saltmeadow Hay (Spartina patens).  • Brackish marshes that are less salty may have large stands of Giant Cordgrass (Spartinacynosuroides) and Sawgrass (Cladiumjamaicense).  Black Needlerush Cordgrass

12. Left: View of a brackish marsh in the Mississippi River Delta, with a simplified diagram showing how biological processes influence marsh elevation relative to sea level. Plant production contributes organic matter, causing upward expansion of the soil surface. As marsh elevation changes, flooding and salinity regimes also change and have a feedback effect on plant production. Increases in CO2 concentration contribute to global warming and sea-level rise but also stimulate plant production, leading to faster gains in elevation.