As you step onto the bridge, take a look at the tangle of proproots of the Red Mangrove Tree (Rhyzopora mangle). The Red Mangrove is usually the front line of the Mangrove Swamp with the prop-roots reaching out into the water. The look of the prop-roots makes the tree appear to be on legs thus the common name Walking Tree. These roots supply oxygen to the roots in the ground where the oxygen is depleted. They also filter out salt for the plant and pollutants from the environment. Organisms such as algae, oysters and barnacles attach to the prop-roots enhancing the food and shelter given to juvenile fish, crabs, and shrimp that use this part of the mangrove swamp as a nursery. In addition to cleaning the water and providing a nurseryground for marine life, Red Mangroves help stabilize the land and protect it from wave action and storms.
Red Mangrove leaves are pointed and new leaves looks like a dunce cap before they unfurl. The flowers have yellow sepals and pale hairy flowers which develop into a propagule which sprouts and grows while still on the tree. You might say that the Red Mangrove gives live birth. The propagule drops off and floats horizontally on the water for 40 days after which the bottom of the propagule sinks and starts to root when it comes in contact with the bottom. So begins a new Red Mangrove tree.
The White Mangrove (Languncularia racemosa) has rounded leaves and two sugar glands on the leaf stem. The sugar glands attract insects that might help with pollination or help repel predators. It usually lives behind the Red Mangroves more toward solid land. White Mangroves excrete salt into their leaves which are constantly being shed. The flowers are small and grow on a stalk and the propagules are small and oval. They only need to be in the water 5 days until they are competent to root.
The Black Mangrove (Avicennia germinans) is usually present in the Mangrove Swamp but cannot be seen here.
At the top of the bridge you look out on the small tidal creek that runs behind the Salt Marsh you just visited. This creek joins Alligator Creek which then flows into Charlotte Harbor. The water is tea colored from the tannins leached from the dead leaves. Look for propagules floating on the surface.
The next stop is just a few steps away near the end of the bridge.
