Seaweed production as a nutrient offset for Moreton Bay
University of the Sunshine Coast (USC)
Moreton Bay is a 1,500 km-squared urbanised estuary adjacent to one of the fastest growing regions in Australia. Rapid population growth creates a challenge for wastewater utilities to deal with the increase in nutrient loads. This includes the single largest asset of Queensland Urban Utilities (QUU), the Luggage Point Sewage Treatment Plant, at the mouth of the Brisbane River that discharges into the bay. At the same time, on the eastern side of Moreton Bay, the Queensland rock oyster industry faces reduced productivity due to environmental change, disease and algal blooms, and challenges associated with the business risks presented by monoculture. Here, communities on Minjerribah (Nth Stradbroke Island) are also investigating new opportunities during their transition away from sand mining, and Quandamooka Yoolooburrabee Aboriginal Corporation (QYAC) has Native Title on a large tract of the Moreton Bay Marine Park, which to date is mostly unutilised. Seaweed production offers a unique and timely solution to address some of the economic, environmental and social challenges in Moreton Bay. Seaweed farming is a “no-feed” form of aquaculture; it is zero waste and compatible with oyster farming and marine park zoning. Seaweeds grow quickly and strip nutrients from the water column, draw down carbon dioxide and can remove pollutants such as heavy metals. At the right scale, seaweed farming will reverse environmental change. Because of this, QUU and the University of the Sunshine Coast (USC) are evaluating how much nutrient can be extracted from the bay as an offset for their discharge licences, to avoid substantial capital investment in sewage treatment whilst delivering better environmental outcomes for each dollar spent. At more than 25 million tonnes per year, seaweed is the largest marine crop in the world. Southeast Queensland is the perfect setting for developing a seaweed industry – ample light, warm water and existing aquaculture leases with farmers, such as Moreton Bay Rock Oysters (MBRO), seeking to diversify their production. Investing in seaweed production will create a new industry for our coastal communities with accountable environmental services and sustainable products.
1. Compare and contrast the nutrient offset and sequestration potential of target seaweeds in controlled experiments
2. Evaluate seaweed production systems using commercially available aquaculture equipment during the scale-up of target seaweeds
3. Determine the yield and properties of harvested seaweed from a year-round pilot production trial at two sites within Moreton Bay
4. Assess the potential effects of seaweed culture on water quality and adjacent marine animals and vegetation
5. Model the removal of nutrients, carbon and other pollutants and the offset capacity of seaweed farming for Moreton Bay