Eutrophication and Dead Zones

The Problem 

Eutrophication is the process by which excess chemical nutrients enter waterways. These nutrients cause algae to bloom in large numbers because they consume it as food. The algae blocks out the sunlight other animals, like the zooxanthellae that provide coral with nutrients, need for photosynthesis and for survival. Also, bacteria that consume the decaying algae require a large quantity of oxygen to grow, limiting the amount other organisms can use. Areas that become low in oxygen are considered hypoxic, and areas of no oxygen are anoxic. Low oxygen areas can create "dead zones," large areas where limited life is possible due to the absence of sufficient oxygen. Many organisms are effected by algal blooms, especially if the type of algae creates toxins that are harmful to its health. Massive fish kills can result, obviously harming tons of species, including humans who visit or live near the beach. Over 60% of the coastal rivers and waterways of the United States are affected by some form of eutrophication. 

The Causes

Nutrient pollution enters waterways because of sources like agriculture, aquaculture, septic tanks, wastewater, runoff, industry, and combustion from fossil fuels. Chemicals travel though the air, surface water and/or groundwater. Some of the most prevalent nutrients used are nitrogen and phosphorous. 

In order to fertilize the plants we grow, humans add millions of tons of chemicals into the environment every year. In 2008 alone,  54.9 million tons of raw materials with 21.5 million tons of nutrients were applied in only the United States. These numbers are continuing to increase each year. About 20% of these chemicals escape into the environment via groundwater or surface runoff into nearby areas. Feces excreted by livestock animals and waste from aquaculture also escape into the environment and add too many nutrients to the waterways. 

Wastewater from industry is not usually filtered for nutrients so they can easily end up in the ecosystem. Leaching from septic tanks and runoff from yards are also contributors to the problem. 

The burning of fossil fuels adds a lot of nitrogen to the air. This nitrogen can form acid rain and smog and also end up in the oceans. 

What Can You Do?

In order to minimize the harmful effects of eutrophication on marine species, we must limit our uses of fertilizer and other nutrient sources as much as possible. DON'T put fertilizer on your yard if you live close to waterways. DON'T fertilize if it looks like it's going to rain because then the nutrients will be lost and enter the environment. DO use native plants species in your yard because they are already adapted to the environment and will not need as many extra nutrients to grow. By limiting waste, we can make the world a better place!

Sources: 

http://oceanservice.noaa.gov/education/kits/estuaries/media/supp_estuar09b_eutro.html

https://www.tfi.org/statistics/statistics-faqs

http://www.wri.org/our-work/project/eutrophication-and-hypoxia/sources-eutrophication

Shoreline Degradation and Effects on Marine Life

More people are seeking out coastal land for development so shorelines are slowly becoming devastated worldwide. Coastal areas that have the greatest number of people consequently have the largest level of shoreline degradation. Beaches are diminished by houses, sea walls, and other things that prevent the environment from staying natural and flowing normally. This has a tremendous effect upon wildlife that call these precious environments home. 

Natural environments, such as mangroves, are being ripped up so that homes, hotels, businesses, or other structures can be created. The removal of these native habitats has a negative effect on the environment because these types of plants hold together the sand and prevent erosion of the land. They are also important homes for many types of marine life. The mangroves in Bimini, Bahamas are important sites for juvenile lemon sharks because their large roots protect these young animals from being eaten my larger predators. Many other species of fish, crustaceans, mollusks, and other organisms also call this habitat home. However, there is a large resort now on the island that destroyed the vital mangrove habitat to create beaches and many of these species are now at risk. The hotel also has plans to create a golf course, which would destroy even more. 

The removal of one species can cause more and more species to die off because they are connected via the food web. They will no longer be able to feed off of other species and other organisms will be unable to eat them. The removal of one species can destroy countless others. 

One paper estimated the amount of shoreline degradation in the Stockholm archipelago of the Baltic sea to determine the effect on fish species in the area. Between 1960 and 2005, about 40% of the shoreline had been developed for human purposes. Each year, only about 0.5-1% of the shoreline was developed, showing that small changes over the years can still have a large impact overall. The shoreline habitats were home to many species now at risk, including northern pike, Eurasian perch, and roach. 

One of the major causes of development is the decision of home buyers. Once one person decides to put up a sea wall along their property, many others will follow and eventually the natural landscape will disappear. Many people are concerned about the environment and should be encouraged to keep it as natural as possible because it will be better for the environment, as well as prettier for them to look at.

Invasive marine species can also be more attracted to normal concrete than native species are, thus they are better able to increase in number while the natural species are outcompeted.

Some ways to help with the problems of degradation include habitat restoration, better management levels and habitat creation. Another way to help is to use more environmentally friendly building materials. For example, people could use ECOncrete instead of regular concrete when building sea walls. ECOncrete has a lower pH than normal concrete so more small coastal organisms can grow. It is also more porous so there is more surface area for these small creatures to bind to. There are also larger crevices for fish and other bigger creatures. Of course it is better to leave these areas natural, but if development needs to happen, people should use more ecologically friendly methods.

Sources: 

http://www.unep.org/dewa/vitalwater/article180.html 

http://inhabitat.com/searc-reintroduces-marine-life-in-coastal-cities-with-econcrete/

http://www.ncbi.nlm.nih.gov/pubmed/24943864

ley.com/doi/10.1111/conl.12114/abstract;jsessionid=54A50A3CB61A58F8A49D367199D8492F.f02t02