Spring 2024 Excursion Report
April 26, 2024

Horn Point Laboratory and Blackwater Wildlife Refuge
Cambridge, Maryland

Horn Point Laboratory

As sea levels rise, coastal areas are threatened. This can have negative effects on infrastructure, as well as the coastal environment as it’s destroyed. Sea level rise is measured and monitored by Horn Point Laboratory in several different ways as they use tools to measure other properties of the water such as salinity and water columns. Similarly, they monitor the types of plants and animals that are present in certain areas to determine how threatened the coastal ecosystems are. To protect the coasts and adapt to the rise in sea level, they are implementing oyster castles. These are structures made of cinder blocks that oysters can grow onto. Over time, they form breakwaters, stabilize sediment, and create marine habitats. This protects the coastal ecosystem and supports biodiversity.

Similarly, as a result of excessive nutrients and sea level rise, many marsh ecosystems are threatened. Marshes are home to a wide variety of organisms, that are at risk of losing their habitats. Horn Point Laboratory is actively monitoring marshes at Poplar Islands to determine the best ways to proceed in protecting these habitats. This involves measuring biomass and sediment elevation, and testing for the effects of excessive nutrients. To address the situation, they have begun creating wetlands at Poplar Island with dredged material. This is a sustainable way to keep these habitats alive. They have planted native species on the island and are continuing to monitor it to determine if this strategy is successful at supporting the habitat.

Finally, there are patterns of harmful algal blooms in the Chesapeake Bay and other waters resulting from excess nutrients polluting the waters. These algal blooms can prevent sunlight from reaching submerged aquatic vegetation, thereby preventing photosynthesis from occurring. This process of eutrophication causes dead zones to form where no life can exist. Similarly, shellfish can consume toxins from the algae and accumulate it in their tissue. This means that humans are also at risk if they consume contaminated shellfish. Scientists in Florida collect samples from the Gulf of Mexico to measure the nutrients and determine the relationship between temperature, light, and the growth of algae cells. At Horn Point Laboratory, they are also measuring the relationships between growth and temperature, as well as the relationship between photosynthesis and temperature. They are developing projects to help predict where these harmful blooms will occur so that they can better combat them.


Blackwater National Wildlife Refuge

The function of Blackwater National Wildlife Refuge is to provide habitat for a diversity of organisms in their marshes, while also educating people about the importance of the refuge. They use guided drives and trails to teach visitors about the importance of the ecosystem and how much nature is worth appreciating and respecting.

The Wildlife Drive serves as an important form of outreach for the refuge by giving visitors the opportunity to actually see the wildlife while learning bits and pieces about conservation and the importance of these habitats to some of the specific animals they may encounter. Similarly, they can also see the effects of climate and habitat changes on the refuge. The forests are converting into tidal wetlands, characterized by the presence of plants like phragmites, which are able to grow in the water and take over tidal areas. Many of the trees are dead or dying where the old tree line was. Instead, the line is being pushed back as the sea level rises and saltwater encroaches. The salinity is becoming too high to support the trees, so ghost forests form where there was once an abundance.



To reach out to the community, both Horn Point Laboratory and Blackwater National Wildlife Refuge make efforts to spark people’s attention. At Horn Point Laboratory, there is a giant pile of oyster shells present for visitors to begin to quantify these organisms. They also incorporate an area with representative oyster shell piles for the last several years. These piles show that some years there are a plethora of oysters that grow and thrive, while other years face high levels of salinity or other factors that may make conditions less favorable for these organisms. This visual representation helps visitors understand the impact and the importance of the work being done at the Laboratory to help support the Chesapeake Bay. Alternatively, Blackwater National Wildlife Refuge has developed several interactive trails for this purpose. They educate visitors after drawing them in with the nature trails. These trails keep visitors engaged and take that opportunity to teach them while they are taking in the habitat around them. Similarly, in their visitor center, they have several displays showing some of the native species that live on the refuge. Also displayed are local winners of the junior duck stamp contest. This is a great way to engage the local community and teach them about the importance of duck conservation and marsh conservation. It also catches the attention of visitors, who learn more about the conservation efforts while viewing the displayed artwork.