Publications by authors named "Vaughan Keesing"

Tributyltin is an organotin chemical that has been commonly used in ship antifouling paints. Despite the global total prohibition of tributyltin-based paint in 2008, tributyltin continues to be found at toxic levels in areas of high maritime traffic such as ports and harbors. A remediation program was conducted at a New Zealand port to reduce tributyltin and copper concentrations to acceptable values.

View Article and Find Full Text PDF

Well validated and reliable biological assays using local and native species are required to characterise the impacts of pollution on ecosystem health. We identified a native estuarine pelagic copepod species suitable for assessing the ecotoxicological impact of anthropogenic contaminants. Gladioferens pectinatus fulfilled the necessary-selection criteria of: wide distribution and abundance across New Zealand estuaries, ease of maintenance in the laboratory, short life cycle, sensitivity to toxicants with different modes of action, and providing reproducibility of biological response to toxicants.

View Article and Find Full Text PDF

Urban estuarine sediments are sinks to a range of contaminants of anthropogenic origin, and a key challenge is to characterize the risk of these compounds to receiving environments. In this study, the toxicity of urban estuarine sediments was tested using acute and chronic bioassays in the benthic harpacticoid sp., and in the planktonic calanoid , two New Zealand copepod species.

View Article and Find Full Text PDF

Reliable environmentally realistic bioassay methodologies are increasingly needed to assess the effects of environmental pollution. This study describes two estuarine sediment bioassays, one acute (96 h) and one chronic (14 d), with the New Zealand harpacticoid copepod Quinquelaophonte sp. utilising behavioural and reproductive endpoints.

View Article and Find Full Text PDF

Worldwide, estuaries are under increasing pressure from numerous contaminants. This study aimed to identify a suitable marine harpacticoid copepod species for toxicity testing of New Zealand estuaries. Multiple aspects were considered for species selection and included: a broad regional distribution, ease of culture, reproductive rate under laboratory conditions, sexual dimorphism, and sensitivity to contaminants.

View Article and Find Full Text PDF

Estuarine sediment contamination is a growing significant ecological issue in New Zealand. Methods of assessing toxicity and ecological impacts in a cost effective way are currently limited. Further to that is a need to develop bioassays that generate data quickly and cost effectively and have ecological relevance to the wider community.

View Article and Find Full Text PDF

Meiofauna composition was investigated for six field sites, including polluted and non-polluted sites, within two regions (Auckland and Bay of Plenty) during winter (July-August 2004) in the North Island of New Zealand. Physico-chemical parameters were measured during the sampling period and meiofauna distribution and abundance were compared with these measured parameters. Analysis of meiofauna abundance indicated that foraminiferans, nematodes and ostracods were the taxa that contributed to the variability between field sites within the Auckland region.

View Article and Find Full Text PDF