Trace metal run-off associated with urban and industrial development poses potential threats to seagrasses in adjacent coastal ecosystems, Seagrass from the largest urban (Moreton Bay) and industrial (Port Curtis) coastal regions in Queensland, Australia were assessed for metal concentrations of iron (Fe), aluminium (Al), zinc (Zn), chromium (Cr) and copper (Cu), Trace metal concentrations in seagrass (Zostera capricorni) leaf and root-rhizome tissue had the following overall trend:

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A paleo-ecological reconstruction of long-term changes in the distribution of submersed aquatic Vegetation (SAV) in a Chesapeake sub-estuary was made using dated sediment cores on transects going from shallow (< 0.5 m) to deep (> 2 m) waters. Maynedier and Saltworks Creeks, branches of the Severn River, have had substantial losses of SAV, similar to many parts of the upper Chesapeake Bay.

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The impact and recovery from exposure to the herbicide diuron [DCMU; 3-(3′,4′-dichlorophenyl)-1,1-dimethylurea] was assessed for three tropical seagrasses, maintained in outdoor aquaria over a 10-day period. Photosynthetic stress was detected using chlorophyll a fluorescence, measured with a Diving-PAM (pulse amplitude modulated fluorometer).

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Water samples were collected within river mouths, at river plume sites and at well flushed ocean-influenced sites within Moreton Bay, a shallow subtropical embayment in south-eastern Queensland. Rates of inorganic nitrogen (NH4+ and NO3-) and carbon uptake were determined across temporal and spatial scales by use of N-15 and C-14 incorporation. Phytoplankton productivity, measured as CO2 uptake, was highest at the river mouths.

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Scientists from the University of Maryland Center for Environmental Science have evaluated the scientific understanding and uncertainty related to five issues regarding the environmental effects of placement of dredged sediments at Site 104, at the head of the deep, natural channel of the Chesapeake Bay. This assessment was based on reviews of relevant studies and impact statements as well as on the scientists’ extensive knowledge and experience concerning the Chesapeake Bay ecosystem.

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Several coastal areas in southeast Queensland, Australia have been affected by blooms of the cyanobacterium Lyngbya majuscula Gomont ("Mermaid hair"). Lyngbya majuscula blooms have caused respiratory irritation, eye inflammation and severe contact dermatitis in fisherman and swimmers as well as causing reduced fish catch, seagrass loss and localized inputs of nitrogen through nitrogen fixation.

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Soil disturbance in coastal regions could be linked to a variety of deleterious environmental impacts. The existing data are preliminary, but there is sufficient evidence to raise the issue to a higher priority for both research and management.

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Survival and recovery of the seagrass Halophiln ovalis (R.Br.) Hook during and after light deprivation was investigated to assist in the interpretation of recent losses of Halophiln spp. in Queensland, Australia. Light deprivation experiments were conducted in outdoor aquaria and in situ at two water depths. Halophiln ovalis plants were deprived of light for a maximum of 30 days, and recovery processes were investigated for up to 18 days following 15 days of light deprivation.

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Rapid global expansion of the aquaculture industry has prompted the need for development of techniques for effective environmental management. In intensively farmed regions, aquaculture effluent has resulted in environmental degradation of receiving waters. The issues to be addressed include analysis of effluent water quality, determination of the ecological impact of effluent on the ecosystem, and development of remediation strategies to reduce these impacts.

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Microbial nutrient cycling in seagrass sediments

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