Chemistry of wetland dredging: Difference between revisions

[[File:Louisiana wetlands aerial view.jpg|thumb|397x397px|Overhead view of Louisiana wetlands.]]Wetland chemistry is largely affected by dredging, which can be done for a variety of purposes. [[Wetland]]s are areas within floodplains with both terrestrial and aquatic characteristics, including marshes, swamps, bogs, and others.<ref name=":1">{{Cite book|title=Classification of Wetlands and Deepwater Habitats of the United States|last=|first=|publisher=United States, Fish and Wildlife Service|year=1979|isbn=|location=Washington D.C.|pages=|quote=|via=}}</ref> It has been estimated that they occupy around 2.8x10⁶ km², about 2.2% of the earth’s surface, but other estimates are even higher.<ref name=":2">Reddy, K.R., E.M. D'Angelo, and W.G. Harris. 2000 Biogeochemistry of Wetlands. In CRC Press. Handbook of Soil Science. Editor-in-Chief, M.E. Sumner. pp. G89-119</ref> It has also been estimated to have a worth of $14.9 trillion and are responsible for 75% of commercial and 90% of recreational harvest of fish and shellfish in the United States.<ref name=":0">{{cite journal | last1 = Constanza | first1 = R. R. | last2 = d'Arge | first2 = R. | last3 = de Groot | first3 = R. | last4 = Farber | first4 = S. | last5 = Grasso | first5 = M. | last6 = Hannon | first6 = B. | last7 = Limburg | first7 = K. | last8 = Naeem | first8 = S. | last9 = Paruelo | first9 = J. | last10 = Raskin | first10 = R.G. | last11 = Sutton | first11 = P. | last12 = van der Belt | first12 = M. | year = 1997 | title = The value of the world's ecosystem services and natural capital | url = | journal = Nature | volume = 387 | issue = | pages = 253–260 }}</ref><ref name=":3">{{Cite web|url=https://www.epa.gov/sites/production/files/2016-02/documents/wetlandfunctionsvalues.pdf|title=Wetland Functions and Values|last=|first=|date=|website=www.epa.gov|publisher=U.S. Environmental Protection Agency|access-date=}}</ref> Wetlands also hold an important role in [[water purification]], storm protection, industry, travel, research, education, and tourism.<ref name=":3" /> Being heavily used and traveled through, dredging is common and leads to continuation of long-term [[environmental degradation|damage of the ecosystem]] and [[land loss]], and ultimately a loss in industry, homes, and protection.<ref>{{Cite web|url=http://pubs.usgs.gov/fs/la-wetlands/|title=Louisiana Coastal Wetlands: A Resource At Risk - USGS Fact Sheet|last=Shirley|first=Jolene S.|website=pubs.usgs.gov|access-date=2016-11-29}}</ref>

Wetlands undergo different chemical reactions depending on a variety of parameters, including salinity and pH. [[Redox|Redox reactions]] have a major effect on wetland ecosystems, as they depend heavily on salinity, pH, oxygen availability, and others. Common redox reactions in wetland include [[carbon cycle|carbon]], nitrogen, and sulfur transformations. Fluctuations in water flow and flooding can change the abundance of the oxidized or reduced species depending on the environment.<ref name=":2" /> Increased flooding and water flow can also change the availability of nutrients to local species.<ref name=":4">{{Cite journal|last=Vymazal|first=J|year=2007|title=Removal of nutrients in various types of constructed wetlands|url=http://www.sciencedirect.com/science/article/pii/S0048969706007212|journal=Science of the Total Environment|volume=380|pages=48–65|via=ScienceDirect|doi=10.1016/j.scitotenv.2006.09.014}}</ref> The further the wetlands change from their original states, the more difficult rebuilding land becomes. The types of [[Environmental mitigation|mitigation]] efforts also change depending on the chemistry, so an understanding of the change is required for effective mitigation.

Wetlands are sources of extreme [[biodiversity]] and ecological benefit. They contain a multitude of species of plants and animals, including 79 species classified as rare, threatened, or [[endangered species|endangered]]. An estimate by the [[U.S. Fish and Wildlife Service]] indicates that wetlands provide for, directly and indirectly, up to 43% of federally threatened or endangered species.<ref name=":3" /> Wetlands are the leading producer of oysters, 50% of the shrimp crop, 75% of the alligator harvest, 27% of the oil and gas, and the [[Port of South Louisiana|largest port complex in the United States]].<ref>{{Cite web|url=http://www.americaswetlandresources.com/background_facts/basicfacts/FAQs.html|title=FAQ's|website=www.americaswetlandresources.com|access-date=2016-11-29}}</ref> The world’s wetlands have an estimated worth of $14.9 trillion.<ref name=":0" />