Global Cycle of Mercury
Mercury cycles in the environment as a result of natural and human activities. Most of the mercury in the atmosphere is elemental mercury vapor, which circulates in the atmosphere for up to a year, and can be widely dispersed and transported thousands of miles from likely sources of emission. Most of the mercury in water, soil, sediments, or plants and animals is in the form of inorganic mercury salts and organic forms of mercury (e.g., methylmercury). The inorganic form of mercury, when either bound to airborne particles or in a gaseous form, is readily removed from the atmosphere by precipitation and is also dry deposited. Wet deposition is the primary mechanism for transporting mercury from the atmosphere to surface waters and land. Even after it deposits, mercury commonly is emitted back to the atmosphere either as a gas or associated with particles, to be re-deposited elsewhere. As it cycles between the atmosphere, land, and water, mercury undergoes a series of complex chemical and physical transformations, many of which are not completely understood. Because it is very toxic and accumulates in organisms, particularly fish, merucry is an important pollutant and one of the most studied.
Mercury cycles in the environment as a result of natural and human activities. Most of the mercury in the atmosphere is elemental mercury vapor, which circulates in the atmosphere for up to a year, and can be widely dispersed and transported thousands of miles from likely sources of emission. Most of the mercury in water, soil, sediments, or plants and animals is in the form of inorganic mercury salts and organic forms of mercury (e.g., methylmercury). The inorganic form of mercury, when either bound to airborne particles or in a gaseous form, is readily removed from the atmosphere by precipitation and is also dry deposited. Wet deposition is the primary mechanism for transporting mercury from the atmosphere to surface waters and land. Even after it deposits, mercury commonly is emitted back to the atmosphere either as a gas or associated with particles, to be re-deposited elsewhere. As it cycles between the atmosphere, land, and water, mercury undergoes a series of complex chemical and physical transformations, many of which are not completely understood. Because it is very toxic and accumulates in organisms, particularly fish, merucry is an important pollutant and one of the most studied.
http://www.jstor.org/pss/221718
Red Tides and Dead Zones
The intensification of agriculture, waste disposal, coastal development, and fossil fuel use has increased the discharge of nitrogen, phosphorus, and other nutrients into the environment. The nutrients are moved by streams, rivers, groundwater, sewage outfalls, and the atmosphere toward the sea. Once they reach the ocean, nutrients stimulate the growth of timy marine plants called phytoplankton or algae. When these species occur in high concentrations, they can color the water and produce what are popularly referred to as “red tides” or “brown tides.” Scientist prefer to call these outbreaks harmful algal blooms of HABs.
Andrew R Solow. (2004). Red Tides and Dead Zones. Oceanus, 43(1), 43-45. Retrieved September 26, 2010, from Research Library. (Document ID: 978253011).
http://proquest.umi.com/pqdweb?index=2&did=978253011&SrchMode=1&sid=1&Fmt=4&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1285545203&clientId=30360
This article was rather technical and extremely boring. The jest of the article was about the equatorial sea level, western Pacific zonal wind, and high-frequency wind variability as precursors of the onset of El Nino and La Nina.
