Rising Tides in Florida's Nature Coast By jackson O'Neill

In recent years, sea level rise has been one of the most pivotal issues in Florida’s gulf coast. Cedar key is particularly threatened, with a mean sea level rise of 1.8 milimeters annually (NOAA). To witness the sea level rise and its effects, a small group of us went to a biological observatory in Cedar Key.

When we arrived, we met with Dr. Mark Allen (pictured above), the director of research at the station. Dr. Allen shared a plethora of examples of how warming ocean temperatures and sea level rise is impacting his local community.

According to Allen and his colleagues, this issue has been impacting humans and wildlife alike. Many species that historically live in the waters of south Florida are migrating north and staying north. Many fish are also adapting to the warming climate. Namely, the Sarah Ruth Snook–just Snook for short–has adopted some interesting migration patterns. While the fish always moved north during the warmer months, in recent years they haven’t been going down south. According to Dr. Allen, a study using tracking tags revealed that some populations of snook would swim up river deltas and inhabit the brackish water during cooler months as opposed to going back south.

Pictured above is a black mangrove along the artificial shoreline. Its size indicates that it's survived multiple winters, something that wasn't possible in previous years.

Another example of species shifting due to climate change are mangroves migrating north (all types: white, black, and even red!). This is not the first time mangroves have been in Cedar Key historically speaking. These mangroves generally occupy the same ecological niche as the grass that they are competing with, resulting in minimal ramifications for the larger intertidal food web.

View of the Nature Coast biological station from the water.

Sea level rise and warming ocean temperatures has forced residents of Cedar Key to adapt as well. pictured above is the biological observatory itself, which is built on stilts like many of the houses built here in Cedar Key. This is by design. In august, Hurricane Idalia devastated Cedar Key. While the winds the town experienced topped 100 MPH, they didn’t inflict nearly as much damage as the storm surge.

Living Shorelines

After leaving the biological station, we began our tour of the living shorelines. To curb some of the adverse effects of sea level rise and storm surge, natural shorelines have been implemented. According to the National Oceanic and Atmospheric Administration, a living shoreline is defined as "a protected and stabilized shoreline that is made of natural materials such as plants, sand, or rock" (NOAA).

The photos above depict one of the natural shorelines we visited. This shoreline is made of concrete habitats for sessile organisms (pictured right), imported sand, and naturally growing grass and mangroves to stabilize the sand.

Living shorelines provide a variety of protections against rising sea levels. One major benefit of living shorelines is that they significantly minimize the amount of sediment eroded by the tides. As sea levels rise, so do erosion rates, so having a method to naturally prevent this is critical. Furthermore, living shorelines minimize tidal surge during large storms. Beyond this, these shorelines promote local biodiversity, which in turn benefits the larger ecosystem.

Seahorse Key

Seahorse key from the boat.

On the second day, we travelled by skiff to Seahorse Key to observe the marine lab and the impacts of hurricane Idalia. Because Seahorse Key is mostly uninhabited, the effects of the rising sea levels can be seen in full swing.

Living shoreline and extensive red mangrove growth at Seahorse Key

As we approached the island, I immediately noticed that mangroves are far more prominent here compared to Cedar Key, likely due to a lack of human presence. There were also living shorelines implemented here.

Lighthouse/observatory at Seahorse Key

After docking the boat, we began our climb towards the lighthouse at the highest point of the island. Though the lighthouse is no longer active, it carries a historical significance to the people of Cedar Key.

From here we descended to the other side of the island. This shoreline in particular took a major hit when hurricane Idalia struck in August. According to the captain of our boat, Idalia eroded away massive amounts of sediment.

Downed trees on the other side of Seahorse Key due to wind and storm surge

Immediately after Idalia struck, the people of Cedar Key came together to rebuild their community. There was no such effort made on Seahorse Key. The juxtaposition between the two demonstrated how devastating the effects of global climate change are to the larger biosphere.

One of many pieces of driftwood that washed up on Seahorse key

As the Earth warms, Sea levels will continue to rise, and hurricanes will grow stronger. With that being said, hope is not completely lost. As we face the imminent threat of climate change, it becomes apparent that drastic changes need to be instituted. Shifts to encourage more sustainable practices in energy usage and waste elimination are critical to lower our carbon footprint, and thus reverse many of the major effects of global warming. Steady water temperatures and lack of chemicals/waste in the ocean will encourage healthier and more sustainable ocean ecosystems. Moreover, as we saw on our trip, one of most prevalent problems coastal cities, including Cedar Key, are facing is the increasing severity of natural disasters. Mass flooding, decimation of the built environment, and energy outages are all critical problems resulting from severe natural disasters that affect the residents of these towns and subsequently affect the surrounding environment through debris and destruction. If we as a collective work to limit our carbon footprints, practice sustainable habits, and increase disaster preparedness, coastal ecosystems are given the opportunity to thrive. A trusted source for more information on living shorelines and how to manage rising sea levels is the National Oceanic and Atmospheric Administration.