The effects of climate change are far reaching - what changes can you see today?
There are two stages for this EarthCache. While you’re visiting them, there are some key observations we ask that you submit before logging the EarthCache. Please submit these in the message center or to nps_ever_science_comms@nps.gov.
At Stage 1
- Find the sign with numbered tick marks poking up out of the water of the borrow pit on the west side of the site. This is called a staff gauge and is used to record the stage, or water level in reference to elevation, not ground level. If the water level is at 5 feet, this means the water level is 5 feet above mean sea level, not 5 feet above ground level. What is the water level currently? Submit a picture showing the water level on the staff gauge.
- When water levels get high enough in Shark Slough, the Shark Valley Loop Road floods. How do you think this will impact visitor access to this location if wet seasons become wetter? How might the stability of the road be affected or will it?
At Stage 2 - from the top level
- During periods of drought, if peat soils completely dry out, they begin to break down leading to subsidence. How do you think the landscape before you would change if drought led to widespread subsidence in the freshwater sloughs? How could saltwater intrusion exacerbate this change?
- Please take a photo from the EarthCache roughly in each of the 4 cardinal directions (North, East, South, West) and submit these.
South Florida is extremely vulnerable to the effects of climate change, mainly because of the region’s low-lying elevation. Here, just a few inches can be the difference between a wetland and an upland ecosystem. The unique geology of the region, with highly porous limestone bedrock and a surficial aquifer that is used for drinking water, makes the entire region vulnerable to the effects of sea level rise and saltwater intrusion.
Saltwater intrusion happens when an aquifer’s freshwater flow is diminished, usually due to human use, allowing saltwater to fill the void. South Florida’s Biscayne aquifer is replenished in the Everglades as freshwater seeps in, but changes to the flow of water and altered weather patterns due to climate change affect the amount of water available. Sea level rise puts added pressure on the aquifer, literally.
If we do not carefully balance our use of water with allowing freshwater to replenish the aquifer upstream, we could accelerate saltwater intrusion into our drinking water supply. But saltwater intrusion and climate change won’t only affect the water supply to human communities.
Sloughs are deep channels in the otherwise relatively flat Everglades. Shark River Slough is the main flow path for water to enter Everglades National Park. Shark Valley, where you are now, is an area near the slough that really is more a plateau between low places than a valley between high ones – a plateau measured in inches.
This location offers one of the best viewsheds of the River of Grass in the park, but just like our need to manage water for our own use, if we do not restore and carefully manage water flow into the park, climate change will quickly and irrevocably alter this landscape.
One way that climate change is predicted to effect South Florida is by making wet periods wetter and dry periods drier. The peat soils that dominate marsh ecosystems of the Everglades break down when dried out, which not only leads to subsidence, a habitat loss, and associated carbon capture, but peat soils actually release carbon dioxide when they decompose. More frequent intense droughts could worsen the effects of climate change locally and globally.
Additionally, though hard to imagine this far inland, sea level rise by way of saltwater intrusion could affect inland freshwater ecosystems long before ocean waves are lapping at their door. Saltier water in the freshwater Everglades would not only change which plants could grow there, it would also lead to additional loss of peat soils and a resulting release of carbon dioxide.
Please Note: this EarthCache has been developed by Everglades National Park for the enjoyment of visitors. The placement of caches on lands managed by the National Park Service and the U.S. Fish and Wildlife Service remains generally prohibited. The placement of any new cache requires advance written approval from the park.
Additional Information:
Saltwater intrusion is the process where seawater pushes against and infiltrates underground freshwater reservoirs called aquifers. South Florida’s Biscayne aquifer is a surficial aquifer because it lies just below the surface and is replenished by groundwater and rainfall. South Florida’s porous limestone bedrock means that there is often interchange between the aquifer and both ground and surfacewater. This means that saltwater intrusion could eventually make it impossible for plants intolerant of saltwater to grow in areas far from the coast.
In addition, storm surges can move saltwater deep into freshwater ecosystems where this salt can persist and lead to ecosystem-altering plant community changes. Continued sea level rise and climate change-driven increases in intensity or frequency of tropical cyclones will allow the impact of saltwater intrusion and storm surges to penetrate farther and farther inland.