Thursday, December 4, 2014

In California, Demand for Groundwater Causing Huge Swaths of Land to Sink.
http://news.nationalgeographic.com/news/2014/03/140325-california-drought-subsidence-groundwater/

The article talks about the very common issue in the USA and the world which is the pumping of underground water leading to sink-age of land. This issue is a very common one in Florida, in which recently a hotel sunk in the ground.
This issue is a common one in the San Joaquin, from 1930 to 1970 the ground level sank by around 9 meters (USGS report). As groundwater supplies 1/3 of water to California even more in drought seasons, underground pumps are built in order to extract water and supply all the counties with water. In the subsidence, an investment of over 800 million needs to be conducted in order for the restoration of the San Joaquin River to be restored. Recently a survey has been conducted related to the sink ages in which USGS thought that their data was wrong because the land had settled so much as Rick Woodley the bureau resource manager. Many construction sites that were near the river were delayed due to the restoration. 

However, this issue is not only present in the USA, it is occurring more and more in Russia and its neighboring countries. 
10
In Pictures: Russia Sinkholes
These causes are not due to water extractions, but may be the cause from various floods or chemical dissolution of carbonate rocks.
National Geographic 
Invasive Asian Carp Found Breeding in "Surprising" Location
Brian Clark Howard
March 11, 2014
http://news.nationalgeographic.com/news/2014/03/140311-asian-carp-upper-mississippi-invasive-species-fish/



Recently it was discovered that the invasive Asian carp has made it into the upper Mississippi River. This invasive species was introduced into the American ecosystem around 20 years ago, though the recent discovery came very surprising. Asian Carp eggs were found in the Upper Mississippi River along with late-stage embryos. This recent discovery is 250km further upstream than at the last known location. 
The problem with the Asian carp is that it is an invasive species potentially harmful for the delicate ecosystem. An Asian carp can grow up to 50 Kg, making it the top predator, eating large amounts of plankton and aquatic vegetation. The fear for sports fishers is that their current preferred species will die out. In order to counter this invasion the local government already invested several 100 million dollars into the effort of stopping the spread. Possible solutions are Electric barriers, water guns, and scent-based lures. Due to fishers catching Asian carp regularly the advance of this species is well documented. Currently scientists are puzzled as to how the species managed to spread so far. The Asian carp is described as a gernal term for several species; the bighead (Hypophthalmichthys nobilis), silver (Hypophthalmichthys moltrix), grass (Ctenopharyngodon idella), and black carp (Mylopharyngodon piceus). These species are known invasive species negatively affecting the American river eco systems. Generally Asian carp are considered a better food source though than the native Carp. The danger is that is the carp reaches the great lakes it can possibly endanger the ecosystem. This high ecological risk is being taken serious causing the investment of millions in order to prevent the Carp from reaching the Great Lakes.

The danger with invasive species is the possible effects for the ecosystem. Invasive species often adapt faster allowing them to exploit their new eco system disregarding the carrying capacity. This is very dangerous as often it is almost impossible to get rid of these invasive species, as an example the raccoon is Western Europe or several species in Australia. The methods used to stop the Carp are though very questionable as they simply seems as a waste of money, introducing a control variable such as nets would allow for the government to limit the Asian carp population. If the carp does enter the Great lakes simply using nets with larger gaps allowing for the indigenous species to pass through but not the carp can be a very effective limiting factor.