Black Bayou Culverts Hydrological Restoration (CS-29)

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The marsh within this area has been suffering from excessive water levels within the lakes subbasin that kills vegetation, prevents growth of desirable annual plant species, and contributes to shoreline erosion. Black Bayou offers a unique location in the basin where the water in the lakes subbasin and the outer, tidal waters are separated by only a narrow highway corridor.

Project components include installing ten 10 foot by 10 foot concrete box culverts in Black Bayou at the intersection of Louisiana Highway 384. The structure discharge will be in addition to the discharges provided by Calcasieu Locks, Schooner Bayou, and Catfish Point water control structures.

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The project features are located in southern Calcasieu Parish, Louisiana. The majority of the project area is located east of Calcasieu Lake and includes areas north of the Gulf Intracoastal Waterway and west of Grand Lake in Cameron Parish, Louisiana.

Construction has been completed.

This project is on Priority Project List 9.

Federal Sponsor: NRCS

Local Sponsor: CPRA

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Stress Part II: Flooding and Hypoxia

Wetland inhabitants must also deal with flooding stress. All parts of a plant must have oxygen, which causes problems when a plant is rooted in hypoxic soils and it is flooded. Gases diffuse about 10,000 times more slowly through water than through air, and wetland soils are often inundated and hypoxic. This poses an issue for supplying roots with enough oxygen since they don’t have any around them. Some root systems will have adventitious roots, which means they extend above the surface of the water or soil to allow gas exchange with the atmosphere.[1] Red mangroves have prop roots, black mangroves have pneumatophores, and both supply oxygen directly to the root system rather than relying on transport all the way from the leaves to the roots.[2]

Hypoxia can be caused by eutrophication and decomposition. Hypoxia and anoxia are dangerous to most plants and animals because most cannot live only with anaerobic (without oxygen) respiration. Bacteria can sometimes live in anoxic conditions by using different electron receptors that are more plentiful in wetland soils like sulfates. Plants can sometimes cope with hypoxia thanks to adaptations like aerenchyma development in their roots. Aerenchymous tissues are much more porous to allow gases to diffuse up to 30 times more easily through a plant! In animals, lungs can allow some fish, mammals, and aquatic gastropods (snails) to live in hypoxic waters, but many fish have gills that are not adapted to hypoxia. The Gulf of Mexico along Louisiana’s coast boasts one of the largest hypoxic zones in the world with a peak area of over 8,500 square miles in 2017, where many commercial fisheries have seen a large decline in fish catch. [3]

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Photo from NOAA, Dead Zone 2017

Works Cited:

[1] Gilman, Sharon. “Plant Adaptations.” ci.coastal.edu/~sgilman/778Plants.htm.

[2] “Adaptations.” Adaptations :: Florida Museum of Natural History, http://www.floridamuseum.ufl.edu/southflorida/habitats/mangroves/adaptations/.

[3] “Gulf of Mexico ‘Dead Zone’ Is the Largest Ever Measured.” Gulf of Mexico ‘Dead Zone’ Is the Largest Ever Measured | National Oceanic and Atmospheric Administration, web.archive.org/web/20170802173757/http:/www.noaa.gov/media-release/gulf-of-mexico-dead-zone-is-largest-ever-measured.

Featured image is of Rhizophora mangle (red mangrove) from Flickr by barloventomagico

Salinity Stress and Tolerance

Living in any habitat comes with hurdles that make it harder for plants and animals to thrive. We call these hurdles “stress”. Coastal wetlands demonstrate several kinds of stresses to both plants and animals. Through many years of evolution, plants and animals have adapted to living with these stresses, also called being “stress tolerant”. Adaptations can be in physical structure changes or on the smaller scale (cellular). Some stresses that come with living in coastal wetlands include salinity (the amount of salt or ions in the water), inundation (flooding at least above the ground, sometimes even higher than the whole plant), and hypoxia (low dissolved oxygen in the water). [1]

Salt water intrusion has been increased by dredging navigation channels among other impacts. Saltwater intrusion makes fresh bodies of water more saline than they usually are. The problem with this is that the plants that live in such places are adapted to live in fresh water and generally cannot deal with increases in salinity more than 1 or 2 parts per thousand (ppt). For reference, the Gulf of Mexico’s average salinity is approximately 36ppt. Some plants, though, can live in full-strength sea water. For example, the black mangrove (Avicennia germinans) has several adaptations that let it keep its cells safe from high salinity. Like smooth cordgrass (Spartina alterniflora), black mangroves excrete salt onto their leaves to get it out of their systems.[2] Some fish have similar adaptations in their gills that allow them to keep their internal salt concentrations at safe levels.

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Salt Crystals accumulate on A. germinans leaves (Photo by Ulf Mehlig, found on Wikimedia Commons)

 

Works Cited:

[1] Bradford, Nick. “Stressed Wetlands.” NEEF, 10 May 2016, http://www.neefusa.org/nature/land/stressed-wetlands.

[2] Gilman, Sharon. “Plant Adaptations.” ci.coastal.edu/~sgilman/778Plants.htm.

Featured image is of A. germinans from Wikimedia commons, courtesy of Judy Gallagher

Audubon Zoo – Earth Fest

Environmental awareness is an important factor in protecting the earth, and the Audubon Institute understands that. With the help of Entergy, the Audubon Zoo has hosted Earth Fest for over twenty years to date, celebrating conservation and environment-friendly practices.

This past Saturday, March 24, CWPPRA was one of many organizations to be represented at Earth Fest along with Wetland Watchers, EnergySmart, Sea Grant, and many more. Each of these organizations brought educational activities to be enjoyed by children and adults alike, such as demonstrations of energy-saving appliances, composting, and beekeeping strategies. Participants could paint with produce from a local farmer’s market, learn about the similarities in bone structures between humans and manatees, and get their faces painted. When they were not busy visiting the zoo enclosures or talking to organizations, guests could enjoy a number of local food vendors or live performers at the pavilion, including Grammy-winning Lost Bayou Ramblers from south Louisiana.

CWPPRA Public Outreach spent the day handing out informational booklets about restoration projects, posters from the Protect Our Coast series, and activity books, as well as playing our popular “Wetland Jeopardy” game with any and all who were interested. Many eager and interested visitors participated in the Earth Fest Earth Quest, a game that led them to ask questions to appropriate organizations in exchange for a stamp. 10 stamps earned them a prize of a young plant to take home and care for. Earth Fest had a wide range of attractions that hopefully inspired all visitors to be more conscious of environmental issues and to help in the efforts to live for a healthier tomorrow.

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Mangroves in Winter

The recent cold weather in Louisiana may have been the end of the road for some plants as temperatures dipped into the teens and stayed below freezing for full days. The hibiscus in your garden may have survived because you gave it extra insulation, but what about marsh plants? Louisiana salt marshes are home to black mangroves (Avicennia germinans), but this represents the very northernmost part of their range. Of the three mangrove species found in the continental United States [red (Rhizophora mangle), black, and white (Laguncularia racemosa)], black mangroves are the most cold-hardy, but they are still sensitive to winter weather- they generally cannot establish above 28° N and S latitude because winters are too cold (a sliver of the Birdsfoot Delta is below 29° N, so we really are at their limit).

The three mangrove species are also different in their tolerances for other environmental conditions: red mangroves establish in the intertidal zone, while black and white mangroves are found at higher elevations, and white mangroves can colonize areas with little to no soil. In Florida where all three species occur, mangrove zones can be defined from the water extending inland and up in elevation .

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Red mangroves are found in the intertidal zone, while black and white mangroves establish at higher elevations. Graphic from the Florida Museum of Natural History at the University of Florida (https://www.floridamuseum.ufl.edu/southflorida/habitats/mangroves/zonation/)

Black mangroves are an important component of Louisiana salt marshes, providing habitat to a variety of species. The complex root systems trap and collect sediment, limiting erosion and maintaining land. Juvenile invertebrates and fish find shelter among the roots, while seabird chicks, such as brown pelicans and roseate spoonbills, are protected from high water events and predators up in the branches.

CWPPRA projects that nourish barrier islands and create new marsh habitat help maintain black mangrove populations by providing new land for the plants to colonize; in turn, the mangroves help the new land persist in the face of wind and wave energy.

The People of Louisiana’s Coastal Wetlands

The Coastal Wetlands Planning, Protection and Restoration Act leads the fight against Louisiana’s disappearing coast. The native people of coastal Louisiana are greatly worried about losing their homes, sources of livelihood, and culture if the lands they live on continue to disappear. Saltwater intrusion, marshes becoming open water, and the disappearance of barrier islands and protective wetlands are a few of the challenges facing coastal communities. For centuries, marshes have served as home to numerous people: American Indian tribes, Vietnamese, Croatian Americans, and other groups. All of these coastal residents are familiar with the hardship of living in an area frequented by natural disasters. Most coastal residents have chosen to stay on their lands to defend and protect the ecosystem despite the extreme risks. Without the hard work and effort of diligent landowners and organizations like CWPPRA, coastal Louisiana would be vanishing at a much faster rate.

You can read Watermarks #48 People of the Coastal Wetlands to learn more about this topic.

Louisiana’s State Reptile – The American Alligator

The American alligator (Alligator mississippiensis), the largest reptile in North America, is also known as the state reptile of Louisiana. Ancestors of the American alligator appeared nearly 160 million years ago. Alligators are cold-blooded, and their body temperature is regulated by the environment around them. There are approximately 2 million wild alligators in the state of Louisiana. Alligators can be spotted in ponds, lakes, bayous, rivers, swamps, and even occasionally swimming pools near these coastal areas in the dry months. The highest populations of alligators within Louisiana are found in coastal marshes. Coastal marshes account for about 3 million acres of alligator habitat in Louisiana.

Alligators are predators in the wetland ecosystem. Young alligators typically feed on small animals such as crawfish, insects, small fish, and frogs. An adult alligator’s diet consists of crabs, turtles, nutria, large birds, and sometimes deer. Alligators assist in population control and support diversity in the environment.  During nest construction, alligators dig burrows with their tails in peat, a boggy type of soil, which often facilitates plant growth. The burrows become “alligator holes”, or wetland depressions, which serve as a breeding area to many species other than alligators during dry periods. Alligators are key contributors to the diversity and productivity of coastal wetlands.

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