Occurrence and seasonal variations of algal toxins in water, phytoplankton and shellfish from North Stradbroke Island, Queensland, Australia

A number of marine microalgae are known to produce toxins that can accumulate in shellfish and when eaten, lead to toxic and potentially fatal reactions in humans. This paper reports on the occurrence and seasonal variations of algal toxins in the waters, phytoplankton and shellfish of Southeast Queensland, Australia. These algal toxins include okadaic acid (OA), domoic acid (DA), gymnodimine (GD), pectenotoxin-2 (PTX-2) and pectenotoxin-2-seco acid (PTX-2-SA), which were detected in the sampled shellfish and phytoplankton, via HPLC-MS/MS. Dissolved OA, PTX-2 and GD were also detected in the samples collected from the water column. This was the first occasion that DA and GD have been reported in shellfish, phytoplankton and the water column in Queensland waters. Phytoplankton tows contained both the toxic Dinophysis and Pseudo-nitzschia algae species, and are suspected of being the most likely producers of the OA, PTX-2s and DA found in shellfish of this area. The number of cells, however, did not correlate with the amount of toxins present in either shellfish or phytoplankton. This indicates that toxin production by algae varies with time and the species present and that number of cells alone cannot be used as an indicator for the presence of toxins. The presence of OA and PTX-2s were more frequently seen in the summer, while DA and GD were detected throughout the year and without any obvious seasonal patterns.     

Environmental restoration measures on the Tennessee–Tombigbee Waterway – an update

 The Tennessee–Tombigbee Waterway (Tenn–Tom) was one of the first and largest water resources projects constructed after the enactment of the National Environmental Policy Act of 1969. This highly controversial project was in litigation for 9 of the 13 years it was under construction. Substantial and innovative measures were incorporated into the project design to minimize environmental damage and to promote environmental protection. Additionally, a wide variety of environmental mitigation measures, including the acquisition and management of 35,614 ha of wildlife habitat to compensate for unavoidable impacts. This paper, which updates a paper published by the American Society of Civil Engineers in 1996, presents an update of the environmental and restorative measures incorporated into the design, construction, operation, and management of the Tenn–Tom some 15 years after it was opened for navigation. The paper examines the accuracy of selected predicted impacts, waterway utilization, and the effectiveness of environmental measures. Received: 13 March 2000 · Accepted: 12 June 2000     

Increasing Use of Human-Dominated Habitats as CO<Subscript>2</Subscript> Emissions Warm and Acidify Oceans

Urban and artificial structures are increasingly added to the world’s coasts during a time in which changing climate is forecast to drive shifts in naturally occurring habitats. We ask whether the role of artificial structures as marine habitats will increase in importance relative to their natural counterparts, particularly as natural habitats are negatively affected by ocean warming and acidification. To evaluate this model, we contrasted use of natural (kelp forest and turfing algae) and artificial habitat (plastic pier-piling) by a nest-building amphipod (Cymadusa pemptos) under current and future climate conditions of CO₂ and temperature. Under future conditions, amphipod populations in mesocosms increased, but this did not lead to greater proportional colonization of kelp and turf. Instead, colonization doubled in artificial habitats, and there was increasing production and occupation of nests on artificial habitats relative to natural habitats. In an age when human modification of natural substrata is increasingly cited as an agent of wildlife decline, understanding the future role of artificial habitats as replacement dwellings for natural habitats is critical. We pioneer an understanding of the future role of natural and artificial habitats, identifying the possibility that the role of urban structures as marine habitats may only increase.