Ecological Consequences Of St.lawrence Seaway Exploitation And The U.S.Response(1954-2008)

In 1954,the United States and Canada cooperated to develop the St.Lawrence Seaway,which was officially opened in 1959.Both countries believed that the construction of this waterway would greatly improve the shipping conditions of the Great Lakes and the St.Lawrence River basin,strengthen the economic and trade relations between the Great Lakes and overseas,and create a large number of jobs,with its supporting hydroelectric projects can bring inexhaustible power for the Canadian and American economies.However,the opening of the St.Lawrence Seaway did not live up to the high expectations of its proponents,and not only that,it had serious consequences for the Great Lakes ecosystem-many exotic organisms entered the Great Lakes with the ships passing through the Seaway and took advantage of the competition with local native species,establishing stable populations and profoundly changing the Great Lakes ecosystem.In 2008,the U.S.Court of Appeals for the Ninth Circuit ruled that the U.S.National Environmental Protection Agency was required to remove the Clean Water Act’s exemption for vessels discharging wastewater,and that vessels navigating U.S.waters would be required to obtain a discharge permit and legally comply with the law by discharging treated sewage from their vessels.However,the Great Lakes ecosystem can no longer return to the state it was in before it was destroyed,and both countries will still have to pay a high price for the construction of the St.Lawrence Seaway in the future.This thesis is divided into three parts: introduction,body,and conclusion,of which the body has four chapters.The first chapter introduces the opening of the St.Lawrence Seaway.The opening of the Welland Canal and the Erie Canal led to the "canal era" of rapid economic development in the Great Lakes region,and the United States and Canada attached great importance to the significance of waterway transportation for industrial and urban development in the process of Great Lakes development.With the growth of population and industrial development,the original canal system has appeared to be overwhelmed,so the United States and Canada cooperated to develop the St.Lawrence Seaway,a new waterway costing a great deal of money and significance,is a symbol of mankind’s conquest of nature’s magnificent project.However,the opening of the St.Lawrence Seaway did not perform as well as it should have,and it failed to make a bright economic impact.The second chapter describes the ecological consequences of the development of the St.Lawrence Seaway.The development of the Welland Canal section of the St.Lawrence Seaway accidentally led to the introduction of seven-gill eels into the Great Lakes,resulting in significant losses to Great Lakes fisheries and a blow to the biodiversity of the lakes.However,the U.S.and Canada did not learn their lesson,and the construction of the waterway led to the introduction of more exotic organisms into the Great Lakes,with zebra mussels,quagga mussel,and round goby dealing a fatal blow to the Great Lakes ecosystem,which had not yet recovered from the blow caused by the seven-gill eel.This severe biological invasion nearly reshaped the Great Lakes food web and had a direct impact on industry and tourism along the lakes.The third chapter describes the U.S.response to the biological invasion of the Great Lakes.In response to the biological invasion caused by the development of the St.Lawrence Seaway,the U.S.government and society have taken a number of measures to try to mitigate the effects of the invasion.In 2008,the U.S.Court of Appeals for the Ninth Circuit ruled that the U.S.Environmental Protection Agency was required to remove the Clean Water Act exemption for ballast water discharges,making it mandatory for vessels to obtain permits for discharges of sewage;in the same year,U.S.maritime operators began requiring vessels entering the Great Lakes to flush their holds with salt water from the ocean,thereby reducing the risk of the risk of vessels accidentally carrying exotic aquatic organisms into North American freshwater bodies.Through comprehensive management,no new invasive species have been detected in the Great Lakes since 2008.The forth chapter introduces the new changes in the Great Lakes basin ecosystem in the context of the emerging chaos theory in ecological research,and analyzes the experiences and lessons learned from the development of the St.Lawrence Seaway and its ecological consequences,hoping to provide some insights for biological invasion control in China.In retrospect,the St.Lawrence Seaway marked the great work of mankind in transforming nature through large-scale engineering construction on the one hand,and opened the gateway for harmful exotic organisms to enter the Great Lakes region on the other.The invasive mussels have not only caused heavy economic losses and ecological damage to the United States and Canada,but have also irreversibly reconfigured the food web of the lakes in ways that the proponents of the channel’s development did not anticipate.However,the complexity and chaotic nature of ecosystems does not mean that humans should have a do-as-you-please attitude toward nature,let alone that they can ignore the impact of their actions on nature and do whatever they want,overspending the future.Comprehensive management of ballast water in the U.S.has made it difficult for exotic organisms to enter the shipping lanes,and the native life of the Great Lakes is gradually beginning to adapt to a new environment of coexistence with invaders such as zebra mussels and goby.The positive initiatives recommended by scientific researchers have led to an eventual move toward a more harmonious and healthy relationship between humans and nature in the Great Lakes.