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The 13C, 15N and 34S signatures of a rocky reef planktivorous fish indicate different coastal discharges of sewage
journal contribution
posted on 2023-05-17, 02:21 authored by Gaston, TF, Kostoglidis, A, Suthers, IMWe assessed the effects of primary, secondary and tertiary treated sewage on the stable isotope composition of the viscera and muscle of the zooplanktivorous eastern hula fish (Plesiopidae: Trachinops taeniatus). Fish were collected from three regions during three consecutive summer months for 2 years. In comparison to fish from control sites, the muscle ä 15N of fish at outfall sites was significantly enriched by secondary and tertiary treated effluent. We estimate that 30-50% of nitrogen in hula fish near outfalls may be sewage-derived. The ä34S content of muscle was similar at all regions and sites (20-21‰), although it was significantly depleted by 1-2‰ at the tertiary treated outfall site. Detection of a comparatively minor volume of effluent (<6 ML day -1) in fish muscle may be due to its slower tissue turnover rate and the continuous discharge of effluent at outfall sites, compared to major yet sporadic rainfall or oceanographic events. The isotopic composition of hula fish from near a large primary treated sewage outfall off the coast of Sydney was not significantly different from one of the control sites, indicating a regional effect of four outfalls discharging > 1000 ML day-1. With increasing upgrades to sewage treatment, stable isotopes may become useful tracers of anthropogenic nutrients in an oligotrophic environment.
History
Publication title
Marine and Freshwater ResearchVolume
55Issue
7Pagination
689-699ISSN
1323-1650Department/School
Institute for Marine and Antarctic StudiesPublisher
C S I R O PublishingPlace of publication
150 Oxford St, Po Box 1139, Collingwood, Australia, Victoria, 3066Repository Status
- Restricted