Algal blooms are one of the most common processes in the marine environment – they occur whenever nutrient levels in the water get too high and small photosynthetic algae multiply uncontrollably until the nutrient supply is exhausted. This process is called eutrophication, and while it may seem innocuous – algae are small, after all, how could they really affect the marine environment? Well, these seemingly harmless creatures can end up creating “dead zones”, huge areas of barren seascape primarily found at the outflows of freshwater rivers.
The way in which this happens starts with the first blush of the algae bloom. As the tiny protists multiply, they cloud the water until sunlight can barely penetrate, interfering with the photosynthesis of the marine plants below, which kills them and lowers the amount of oxygen available in the water. The problems are only exacerbated after the nutrient supply runs out and the algae begin to die off – as their billions of tiny bodies decompose, they take up yet more oxygen and plunge the area into a state of hypoxia (low dissolved oxygen, 3-5 mg/L) or worse, anoxia (no dissolved oxygen at all). Fish and other motile organisms flee the area, and benthic organisms that are sessile (immobile) cannot move to more oxygen-rich areas and thus suffocate. This creates a massive area devoid of all life that cannot be repopulated unless oxygen levels rebound.
These dead zones are found throughout the world wherever rivers empty into the ocean, most notably in the Gulf of Mexico, the Baltic Sea, and the southeastern Australian coast. They are caused primarily by a sharp increase in the demand for agricultural products. This demand triggers more usage of fertilizers, which ultimately start the cycle of algal growth and death. Algae blooms are a huge marine problem, decimating large swaths of the ocean annually, and they are almost cocmpletely anthropogenic – caused by our own human greed or carelessness.
Friday, May 27, 2011
Causes of Eutrophication
Algal blooms and eutrophication are basically caused by an excess of nutrients being added to the system. Mainly, these extra nutrients are anthropogenic, stemming from human activity. Stormwater runoff carries such things as fertilizers into lakes and rivers, which all eventually lead to the ocean. These fertilizers are filled with phosphates and nitrates, two limiting nutrients that algae feed on. Once these enter the water column, it is only a matter of time before an algae bloom occurs. The fertilizers can be manmade agricultural fertilizers or “natural” fertilizer from livestock – the former is more potent, but both are prevalent in our waterways.
Solutions for Eutrophication
Aside from the obvious increase in regulations dealing with fertilizer intensity and use or stormwater runoff control, there are several engineering-minded solutions that can be deployed to halt or prevent algae blooms. The easiest is increased replenishment of salt marshes and mangrove swamps. If stormwater has to travel through these natural filters before it reaches the open ocean, the plants there will likely take up the nutrients before the algae have a chance to explode in population. It is natural and very safe, and relatively easy to gain public support for. If bigger natural filters are an issue, true filters can be used at the outflow of rivers and lakes to trap algae which have started to bloom in freshwater. These filters would be unobtrusive and would deal with many different kinds of pollution as well as eutrophication. The mesh of the sponge of the filter would only be a few microns wide, and would likely have to be cleaned or replaced every couple of weeks - more expensive but still relatively simple.
If the algae bloom is already in progress, a technique called ultrasonic irradiation can be used, which involved hitting the algae bloom with high-pitched sound waves in order to puncture the vacuoles that keep them afloat. After being hit by the waves, the algae sink to the bottom and die in seconds. Though this method still depletes oxygen through the rotting algae, the fact that the marine plants gain immediate access to the sun will mostly counteract this. If used early enough, this method can completely halt the effects of an algae bloom and return the area to full prosperity. If used in conjunction with one of the preventative measures, this technology can ensure a bloom-free coastline for the foreseeable future – a definite positive result.
If the algae bloom is already in progress, a technique called ultrasonic irradiation can be used, which involved hitting the algae bloom with high-pitched sound waves in order to puncture the vacuoles that keep them afloat. After being hit by the waves, the algae sink to the bottom and die in seconds. Though this method still depletes oxygen through the rotting algae, the fact that the marine plants gain immediate access to the sun will mostly counteract this. If used early enough, this method can completely halt the effects of an algae bloom and return the area to full prosperity. If used in conjunction with one of the preventative measures, this technology can ensure a bloom-free coastline for the foreseeable future – a definite positive result.
Introduction to Rainforest Deforestation
As the needs of humans and their demands on industry grow, rainforest deforestation is becoming an increasingly large environmental problem. The devastating effects of human activity on the rainforests can be seen in the dramatic reduction in the amount of earth’s surface they cover. Once rainforests coated as much as 14% of Earth’s surface, but today the number is closer to 6%, and shrinking. Every second, one and a half acres of rainforest are lost forever, complete with nearly 137 plant, animal, and insect species every day. Many of these estimated 5,000 species lost every year were never discovered and now never will be. Some estimates hold that the rainforest will be completely wiped out in as little as 40 years.
The possible impacts of this tragedy are menacingly colossal when one considers that nearly half of all plant and animal species on Earth are endemic to the rainforest. About 25% of medicines used in the modern pharmaceutical market are derived from rainforest ingredients. However, currently less than one percent of the trees in the rainforest have been tested for medicinal properties. Imagine the potential contained within this vast pool of resources that is currently being ruined.
The possible impacts of this tragedy are menacingly colossal when one considers that nearly half of all plant and animal species on Earth are endemic to the rainforest. About 25% of medicines used in the modern pharmaceutical market are derived from rainforest ingredients. However, currently less than one percent of the trees in the rainforest have been tested for medicinal properties. Imagine the potential contained within this vast pool of resources that is currently being ruined.
Causes of Rainforest Deforestation
Logging – Logging, the most obvious cause of deforestation, is basically straightforward clear-cutting of rainforests for no other reason than to use the wood for fuel, building, or exportation.
Agricultures-Cash Crops & Cattle Ranching – Native farmers will often clear large sections of forest in order to plant crops or graze cattle that will be shipped to first world countries, because this monoculture is more profitable in the short term However, the soil is not fertile enough to support this for long, and after it depletes in nutrients, new areas of forest must be cleared, leaving the old ones completely devoid of life.
Large Dams - Power companies in third-world will flood large sections of forest in order to harvest hydroelectric power to service the exploding populations of these countries, rather than using the existing power sources more efficiently.
Mining – Mining companies will clear rainforests in order to gain access to the minerals in the ground. Also, the roads built through the untouched rainforest still negatively impact the ecosystem, not to mention the deleterious effects of the air and water pollution from the mine itself.
Development and Overconsumption – As developed nations grow and begin to want more from this earth – more food, clothes, toys et cetera – the natural resources of the planet simply cannot keep up. This greed is one of the root causes of many problems, including deforestation.
Exploitation by Industrialized Countries-Industrialized countries rely heavily on resources they cannot produce themselves, however prices on the world market for third world exports are often low. Countries with rainforests are eager to gain all they can from their resources.
The Role of Poverty and Overpopulation- Overpopulation has increased demand on many goods derived from the rainforest, but people in industrialized nations can consume sixty times the resources as people elsewhere. Overconsumption is only partially caused by overpopulation and is the root cause.
RC GG EJ CR AR
Agricultures-Cash Crops & Cattle Ranching – Native farmers will often clear large sections of forest in order to plant crops or graze cattle that will be shipped to first world countries, because this monoculture is more profitable in the short term However, the soil is not fertile enough to support this for long, and after it depletes in nutrients, new areas of forest must be cleared, leaving the old ones completely devoid of life.
Large Dams - Power companies in third-world will flood large sections of forest in order to harvest hydroelectric power to service the exploding populations of these countries, rather than using the existing power sources more efficiently.
Mining – Mining companies will clear rainforests in order to gain access to the minerals in the ground. Also, the roads built through the untouched rainforest still negatively impact the ecosystem, not to mention the deleterious effects of the air and water pollution from the mine itself.
Development and Overconsumption – As developed nations grow and begin to want more from this earth – more food, clothes, toys et cetera – the natural resources of the planet simply cannot keep up. This greed is one of the root causes of many problems, including deforestation.
Exploitation by Industrialized Countries-Industrialized countries rely heavily on resources they cannot produce themselves, however prices on the world market for third world exports are often low. Countries with rainforests are eager to gain all they can from their resources.
The Role of Poverty and Overpopulation- Overpopulation has increased demand on many goods derived from the rainforest, but people in industrialized nations can consume sixty times the resources as people elsewhere. Overconsumption is only partially caused by overpopulation and is the root cause.
RC GG EJ CR AR
Solutions to Rainforest Deforestation
Unfortunately for the rainforest, most of the causes of its destruction lack easy answers. Overpopulation cannot be solved without extensive and intrusive legislation and widely available birth control. No method currently exists to feasibly curb the population’s growth and the corresponding demand for products of all kinds. Instead the derivative causes of rainforest deforestation must be addressed.
Various forms of regulation are the most obvious resolutions to the problems that cause rainforest deforestation. Industries could be regulated to limit the uses of rainforest-derived materials and ensure that they are gathered in the most ecologically friendly way possible. Of course, these methods might encourage poaching and the international nature of the rainforest makes it difficult to regulate effectively.
Agricultural problems can be eased by extensive research, however. If effort is made to engineer crops that make the best use of the soil possible, farmers would have less need to deforest new sections of the rainforest to get new farm land. Crops that are prepared to deal with the heat and low nutrient conditions in most rainforest areas would stand up well. Additionally, better farm management strategies, like crop rotation, could help add nutrients to the soil instead of only draining them. Agricultural reform like this could involve subsidies to encourage the planting of different crops and to fund the research necessary to develop efficient ones.
Crop rotation, agricultural research, and industry regulation can all contribute to the ultimate solution to rainforest deforestation. If enough support is gathered, measures like this can be implemented and the rainforest will be saved.
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