EPOW - Ecology Picture of the Week

             The Waterways of Amsterdam   ----->

Canals, Amsterdam, The Netherlands

Explanation:  Enjoy the wonderfully scenic waterways of Amsterdam.  This is Holland, part of The Netherlands, and these iconic canals provide access to much of the city's inner meshwork of roads and bike paths.

But canals can have a dark side.  

They can provide access routes not just for tourists but also for (other?) invasive species, particularly if the waterway is artificially constructed and links bodies of water otherwise unconnected.

Classic examples include the Panama Canal of Central America, which host invasive Harris mud crabs that can further invade lakes, clog drainage systems, entangle fish nets, and spread disease.  Highly invasive ascidians ("sea squirts") have been documented in the Suez Canal linking the Mediterranean and the Red Sea, where they can out-compete native species.  Canals are also introduction points of exotic species into the North American Great Lakes, where they can wreak havoc on native ecosystems.  

Back in lovely Amsterdam, the canal waters are being monitored for pathogens such as giardia and cryptosporidium that can pose a risk to human health.  
 

Information:
     Rius, M., and N. Shenkar.  2012.  Ascidian introductions through the Suez Canal: the case study of an Indo-Pacific species.  Marine Pollution Bulletin 64(10):2060-2068.
     Schets, F.M., J.H. van Wijnen, J.F. Schijven, H. Schoon, and A.M. de Roda Husman.  2008.  Monitoring of waterborne pathogens in surface waters in Amsterdam, The Netherlands, and the potential health risk associated with exposure to cryptosporidium and giardia in these waters.  Applied Environmental Microbiology 74(7):2069-2078.