Chemical Parameters in Ships' Ballast Water: Non-Indigenous Species Investigations in the Columbia River
Abstract
Mid-ocean ballast water exchange (BWE) is mandatory for many ships discharging ballast water in the U.S. and other countries in order to reduce the risk of biological invasions. However, a reliable tool for determining whether the procedure took place is still lacking. The Columbia River receives ballast water from ships from Asian trade partners and worldwide ports, thus BWE is important in protecting the river from biological invasions. The current study was conducted as part of the Columbia River Aquatic Nuisance Species Initiative and investigated naturally occurring chemical tracers in coastal and open ocean waters. Several trace elements (Mn, P, U, V, Mo, Ba), chromophoric dissolved organic matter (CDOM) fluorescence and an isotope of radium (223Ra) were investigated as tracers of mid-ocean exchange on five research cruises out of Asia, Europe and the USA, focusing on especially high-salinity source conditions. Several tracers, particularly CDOM, were successful indicators of BWE on multiple cruises although it was not possible to set thresholds that could be unambiguously applied to verify BWE across all cruises. In offshore transects, a large range of decay functions was seen suggesting that in many cases it will be difficult to determine if BWE was performed 200 nmi or 50 nmi from shore.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2006
- Accession Number
- AD1210545
Entities
People
- Gregory M. Ruiz
- Kathleen R. Murphy
- Mark Sytsma
Organizations
- Portland State University