Verification of mid-ocean ballast water exchange using naturally occurring coastal tracers.
We examined methods for verifying whether or not ships have performed mid-ocean ballast water exchange (BWE) on four commercial vessels operating in the Pacific and Atlantic Oceans. During BWE, a ship replaces the coastal water in its ballast tanks with water drawn from the open ocean, which is considered to harbor fewer organisms capable of establishing in coastal environments. We measured concentrations of several naturally occurring chemical tracers (salinity, six trace elements, colored dissolved organic matter fluorescence and radium isotopes) along ocean transects and in ballast tanks subjected to varying degrees of BWE (0-99%). Many coastal tracers showed significant concentration changes due to BWE, and our ability to detect differences between exchanged and unexchanged ballast tanks was greatest under multivariate analysis. An expanded dataset, which includes additional geographic regions, is now needed to test the generality of our results.
Murphy
Kathleen
K
Marine Invasions Research Laboratory, Smithsonian Environmental Research Center, 647 Contees Wharf Road, Edgewater, MD 21037, USA. murphyka@si.edu
Boehme
Jennifer
J
Coble
Paula
P
Cullen
Jay
J
Field
Paul
P
Moore
Willard
W
Perry
Elgin
E
Sherrell
Robert
R
Ruiz
Gregory
G
D001267:Atlantic Ocean; D005453:Fluorescence; D005843:Geography; D015233:Models, Statistical; D015999:Multivariate Analysis; D009930:Organic Chemicals / Q000032:analysis; D010140:Pacific Ocean; D011849:Radioactive Tracers; D011883:Radium / Q000032:analysis*; D012767:Ships; D012965:Sodium Chloride / Q000032:analysis*; D014131:Trace Elements / Q000032:analysis*; D014865:Waste Disposal, Fluid / Q000379:methods*
D009930:Organic Chemicals; D011849:Radioactive Tracers; D014131:Trace Elements; D012965:Sodium Chloride; D011883:Radium