The opening of the Panama Canal in 1913 increased the availability of internationally traded goods and transformed ocean-shipping by shortening travel time between the Atlantic Ocean and Pacific Ocean. The canal spark...The opening of the Panama Canal in 1913 increased the availability of internationally traded goods and transformed ocean-shipping by shortening travel time between the Atlantic Ocean and Pacific Ocean. The canal sparked the growth of port authorities and increased ship tonnage on both coasts of Panama. Since the construction of the Panama Canal, in the 1910s, pesticides, herbicides and chemicals, including arsenic, have been essential for controlling wetland vegetation, including hyacinth, which blocked rivers, lakes, and the canal as well as managing mosquitoes. Pesticides and chemicals flowed into Lake Gatun (reservoir) either attached to sediment or in solution during the monsoon season. Lake Gatun was the drinking water source for most of the people living in the Panama Canal Zone. The United States military base commanders had the ability to order and use cacodylic acid (arsenic based) from the Naval Depot Supply Federal and Stock Catalog and the later Federal Supply Catalog on the military base grounds in the Panama Canal Zone. Cacodylic acid was shipped to Panama Canal Zone ports, including Balboa and Cristobal, and distributed to the military bases by rail or truck. The objective of this study is to determine the fate of arsenic: 1) applied between 1914 and 1935 to Panama Canal shipping lane hyacinth and other wetland vegetation and 2) cacodylic acid (arsenic) sprayed from 1948 to 1999 on the US military base grounds in the Panama Canal Zone.展开更多
The microalgal epibiontic communities of the brachyuran crabs Dorippe quadridens, Schizophrys aspera and Hyastenus hilgendorfi were studied during spring and summer of 2011. A total of 68 microalgal species of four ph...The microalgal epibiontic communities of the brachyuran crabs Dorippe quadridens, Schizophrys aspera and Hyastenus hilgendorfi were studied during spring and summer of 2011. A total of 68 microalgal species of four phyla （Chlorophyta, Bascillariophyta, Cyanophyta and Pyrrhophyta） was recorded in the epibiosis of the investigated brachyuran crabs males and females Generally, Bascillariophyta predominate in number of species over the other microalgal groups, followed by Cyanophyta and Pyrrhophyta, while Chlorophyta was represented by the lowest number of species. Highly percentage of occurrence of microalgal epibionts was observed on the dorsal part of the investigated crabs followed by chela and ventral parts.展开更多
Through high-resolution research of sedimental chronology and the sediment environmental indexes, such as graininess, minerals, magnetic parameters, pigment content, organic carbon and chronology in Ds-co...Through high-resolution research of sedimental chronology and the sediment environmental indexes, such as graininess, minerals, magnetic parameters, pigment content, organic carbon and chronology in Ds-core and Ws-core in Nansihu Lake, the authors analyze the formation cause of the Nansihu Lake and its water environmental changes. Historical documents are also analyzed here in order to reach the conclusion. Researches indicate that the Nansihu Lake came into being about 2500 aBP and its evolution succession can be divided into four stages. In this evolution process, several scattered lakes merge into one large lake in the east of China. This process is distinctively affected by the overflow of the Yellow River, the excavation of the Grand Canal and other human activities.展开更多
Human activities in the Lake Naivasha catchments pose serious ecological threats to sustainable freshwater ecosystem management. The future hangs on the balance of economic exploitation and sustainable watershed conse...Human activities in the Lake Naivasha catchments pose serious ecological threats to sustainable freshwater ecosystem management. The future hangs on the balance of economic exploitation and sustainable watershed conservation. Water abstraction volumes, embedded water/virtual water and chemical analysis of wastewater discharges were assessed. Dissolved oxygen, temperature, Secchi disc depth, benthic organisms＇ population and pesticides used in the farms were determined. The study found that abstraction exceeds safe water yield, farms have also encroached on the riparian lands and connected to the lake through canals allowing effluents to flow directly to the lake. Benthic community populations are low at points where discharge canals enter the lake, indicating inflow of materials are toxic. Canal samples show high contaminant levels of actions for sustainable exploitation of the resource is essential. compared to other sites. Wise use of the resource and implementation The determination of ecological and water footprints are recommend.展开更多
文摘The opening of the Panama Canal in 1913 increased the availability of internationally traded goods and transformed ocean-shipping by shortening travel time between the Atlantic Ocean and Pacific Ocean. The canal sparked the growth of port authorities and increased ship tonnage on both coasts of Panama. Since the construction of the Panama Canal, in the 1910s, pesticides, herbicides and chemicals, including arsenic, have been essential for controlling wetland vegetation, including hyacinth, which blocked rivers, lakes, and the canal as well as managing mosquitoes. Pesticides and chemicals flowed into Lake Gatun (reservoir) either attached to sediment or in solution during the monsoon season. Lake Gatun was the drinking water source for most of the people living in the Panama Canal Zone. The United States military base commanders had the ability to order and use cacodylic acid (arsenic based) from the Naval Depot Supply Federal and Stock Catalog and the later Federal Supply Catalog on the military base grounds in the Panama Canal Zone. Cacodylic acid was shipped to Panama Canal Zone ports, including Balboa and Cristobal, and distributed to the military bases by rail or truck. The objective of this study is to determine the fate of arsenic: 1) applied between 1914 and 1935 to Panama Canal shipping lane hyacinth and other wetland vegetation and 2) cacodylic acid (arsenic) sprayed from 1948 to 1999 on the US military base grounds in the Panama Canal Zone.
文摘The microalgal epibiontic communities of the brachyuran crabs Dorippe quadridens, Schizophrys aspera and Hyastenus hilgendorfi were studied during spring and summer of 2011. A total of 68 microalgal species of four phyla （Chlorophyta, Bascillariophyta, Cyanophyta and Pyrrhophyta） was recorded in the epibiosis of the investigated brachyuran crabs males and females Generally, Bascillariophyta predominate in number of species over the other microalgal groups, followed by Cyanophyta and Pyrrhophyta, while Chlorophyta was represented by the lowest number of species. Highly percentage of occurrence of microalgal epibionts was observed on the dorsal part of the investigated crabs followed by chela and ventral parts.
基金Natural Science Foundation of Shandong Province No.Z2000E01
文摘Through high-resolution research of sedimental chronology and the sediment environmental indexes, such as graininess, minerals, magnetic parameters, pigment content, organic carbon and chronology in Ds-core and Ws-core in Nansihu Lake, the authors analyze the formation cause of the Nansihu Lake and its water environmental changes. Historical documents are also analyzed here in order to reach the conclusion. Researches indicate that the Nansihu Lake came into being about 2500 aBP and its evolution succession can be divided into four stages. In this evolution process, several scattered lakes merge into one large lake in the east of China. This process is distinctively affected by the overflow of the Yellow River, the excavation of the Grand Canal and other human activities.
文摘Human activities in the Lake Naivasha catchments pose serious ecological threats to sustainable freshwater ecosystem management. The future hangs on the balance of economic exploitation and sustainable watershed conservation. Water abstraction volumes, embedded water/virtual water and chemical analysis of wastewater discharges were assessed. Dissolved oxygen, temperature, Secchi disc depth, benthic organisms＇ population and pesticides used in the farms were determined. The study found that abstraction exceeds safe water yield, farms have also encroached on the riparian lands and connected to the lake through canals allowing effluents to flow directly to the lake. Benthic community populations are low at points where discharge canals enter the lake, indicating inflow of materials are toxic. Canal samples show high contaminant levels of actions for sustainable exploitation of the resource is essential. compared to other sites. Wise use of the resource and implementation The determination of ecological and water footprints are recommend.
