The Sea Bird began lifting her anchor at 6:30AM this morning. The prevailing breeze off the Pacific Ocean was steady, coming out of the Northwest. Slowly our vessel began her approach to the north end of the Hull Canal. During this early morning transit our Smithsonian guest speaker Larry Hobbs continued his Gray whale count from the bow of the ship. Many of us remained inside the ship enjoying a final gift shop along with a presentation of, “Plant Tales and other Stories.” Through slides and detailed information we walked back through our entire trip around the tip of the Baja peninsula into the Gulf of California returning to Magdelena Bay looking at the unique botanical environment that is Baja California, Sur. In preparation for our morning hike and afternoon Zodiac cruise we watched as the three varieties of mangroves were visually presented to us. We learned of propagules, numadifors, and reverse osmosis. The intricate nursery world of an over wash Mangrove system became a world we all wanted to explore. Granting our wish our expedition leader arranged for a small group of us to go ashore before lunch to explore the edges of a Mangrove system located at the southern end of the Hull Canal. Upon landing on the beach we began walking along the edge of the Mangrove community. Our first hosts were the black and white mangroves, respectively. The Black Mangrove, a unique plant seemed a bit scruffy, small and timidly colored in a light grayish-green. We soon learned that this member of the Mangrove community is usually found on the outskirts farthest away from the salt water and a plant that does indeed take salt water into it’s system, exuding it through the stomata on it’s leaves...leaving a residue of sparkling salt crystals scattered all over the leaf surface. A close neighbor to the Black Mangrove, though not related botanically is the White Mangrove. Another rather rough looking character, this pale green-leafed plant exudes its intake of salt through it’s leaf surfaces as well, AND, possibly through two small glands located at the base of the leaf on the petiole.
Growing directly in the salt water and on the outside of the Mangrove community is the primadonna of Mangroves, the Red Mangrove. The leaves are silky dark green and quite lush in color. This gorgeous growth is due to a successful exclusion of salt from the plant within the root system directly at the intake point through small lenticels. The Red Mangrove’s salt exclusion system is a type of non-metabolic ultra filtration system. Transpiration at the leaf surface creates negative pressure in the xylem. This causes a type of “reverse osmosis” to occur at the root surface, preventing salt in salt water from entering the plant.
Mangroves have evolved physiological responses to specific conditions and have out competed other species that would normally not be able to exist under these harsh conditions, hence their ability to create actual forests in salt-water estuaries.
During both the hike and our afternoon of kayaking and cruising we had an opportunity to observe some of the other inhabitants who call the Mangrove community their home. Birds use the Mangrove forests as nesting and roosting sights, as well as feeding in the rich waters that form channels all through the Mangroves. We watched cormorants on nests feeding their young. There were brown pelicans, young and mature wearing the bright colors of breeding plumage! We watched white Ibis feeding, reddish egrets, snowy egrets, great blue herons and many, many more birds taking care of their daily lives within the mangroves. On several occasions we were able to be very quiet, and listened to the rich sounds created by these feathered inhabitants carrying on a plethora of sounds that moved out over the water adding delightfully to a second auditory sense.
Upon closer exploration under the canopy of the mangroves we found schools of fish, crabs, snails and upon one particular point an enormous bed of clams, that appeared to be at least ten inches thick!As one zodiac cruise began its return to the Sea Bird, across a mudflat a coyote was spotted…this very healthy richly colored animal continued its walk until it heard our small vessel moving closer to shore. The coyote lifted his ears, stopped for a moment and then made a quick retreat towards the cover of the Mangrove. Slowly both kayaks and Zodiacs returned to our floating home, the coyote, birds, and small critters who live under the water’s surface, a wonderful reminder of the interconnectedness of this diverse ecosystem called a Mangrove estuary.
