South Florida blue waters like the Caribbean
Article by Israel Joffe on the crystal blue waters of South Florida
South Florida is known for its stunning azure waters, a captivating blue that rivals the Caribbean Sea's hues. In contrast, the waters off New York and other northern coastal cities often appear murkier and greyer. The reasons behind these distinct variations involve a complex interplay of light, water composition, and marine life.
Water color, fundamentally, is influenced by the way sunlight interacts with whatever is present in the water. The deep blue color in South Florida is primarily due to the clarity of the water and the lack of substances, such as plankton, sediment, and organic materials. As sunlight penetrates the clear water, it is absorbed and refracted, with the shorter blue wavelengths being scattered and reflected back to our eyes. This process, known as Rayleigh scattering, is the same phenomenon that makes the sky appear blue.
In contrast, the waters of New York and other northern coastal regions tend to be higher in nutrients and, therefore, support more algae and phytoplankton. The abundance of these microscopic plants, along with other suspended particles and sediments, changes the way light is absorbed and reflected. These waters often appear greener or murkier due to the dominant presence of these microscopic plants which absorb sunlight for photosynthesis and reflect more green wavelengths.
The Gulf Stream, a powerful warm ocean current, also plays a significant role in both regions' water color. Originating in the Gulf of Mexico, it carries clear, warm water up the U.S. East Coast. In South Florida, the Gulf Stream runs quite close to shore, which helps keep the water clear and warm. As it travels north, it moves further offshore, and the coastal waters are more influenced by local runoff, river input, and different oceanic currents.
Another significant factor is the type and amount of microscopic and macroscopic life in the waters. South Florida waters, similar to those of the Caribbean, are replete with coral reefs and seagrass beds. These underwater ecosystems, while contributing to the stunning underwater scenery, also play a role in water clarity by reducing wave action, which in turn reduces coastal erosion and sediment resuspension.
Now, let's discuss the role of sargassum, a type of free-floating seaweed that grows in the Sargasso Sea in the Atlantic Ocean. Ocean currents, particularly the Gulf Stream, can carry sargassum from the Sargasso Sea to Florida's shores. While it can be a nuisance to beachgoers due to its smell and texture, it is an important habitat and food source for marine life.
However, in recent years, there has been an increase in sargassum beaching events, known as sargassum blooms, causing significant issues for South Florida and Caribbean beaches. Scientists believe that changing ocean conditions, possibly linked to increased nutrient runoff from rivers, are promoting the overgrowth of sargassum.
When a sargassum bloom occurs, some beachgoers may indeed opt to head to northern beaches. Beaches in places like the Hamptons, while not as warm as those in Florida, tend to be less affected by sargassum due to their distance from the Sargasso Sea and the path of the Gulf Stream.
Despite the challenges posed by sargassum, South Florida remains a vibrant, dynamic ecosystem with waters that continue to charm residents and visitors alike with their Caribbean-like hues. Efforts to manage sargassum influx and preserve these waters are ongoing, recognizing the importance of this unique environment for both people and marine life.