News 2020: Water quality and the environment

PhD student Alan Austin is shedding light on the importance of water quality to help stakeholders better manage the ecological health of estuaries in parts of New England and Brazil.

As an undergraduate student, Alan Austin developed a passion for ocean dynamics after listening to many stories about how oceanographic research benefits the environment. “It was hard to believe that so many large-scale physical and biological features that we take for granted are completely dependent on oceanic processes,” he said.

While pursuing his master’s degree at UMass Dartmouth’s School for Marine Science & Technology, he worked as a field and lab assistant in the Coastal Systems Program lab at SMAST where he learned about the problems within our coastal waters and estuaries. “Alan just volunteered for everything and is an excellent field scientist, so we just had to keep him at SMAST,” says Brian Howes, Chancellor Professor at SMAST and one of Alan’s co-advisors. “Having earned his bachelor’s degree in wildlife biology, with a minor in chemistry, and then earning his master’s degree studying physical oceanographic processes, he was well-positioned to work on estuarine processes, which span all three disciplines – biology, chemistry, and physics,” says Professor Miles Sundermeyer, his other co-advisor.

The result? Alan is now earning his PhD in the dual-degree program jointly offered by UMass Dartmouth and the University of São Paulo. “I thought that this could be a great opportunity to work with two lagoonal estuaries in two separate parts of the world,” said Alan who is comparing the structure and function of a temperate and subtropical estuary in different coastal settings within different regimes of precipitation, temperature, and wind variation. “There are large differences in watershed land-use with higher population densities in New England temperate estuaries, and greater agricultural activity associated with the sub-tropical estuary I am studying in Brazil. All of these differences influence the water quality and ecological health of the estuaries.”

Part of Alan’s research involves conducting field studies to support his circulation/water-quality models. “Within Pleasant Bay on Cape Cod, Massachusetts, the barrier beach that forms the lagoon has been changing on about a decadal cycle,” he explained. “Modeling the hydrodynamics and water-quality patterns within the Pleasant Bay estuary will provide neighboring towns with information on how the water quality of the system is likely to change with changes in the barrier beach and tidal inlet. This will help towns to anticipate and better manage nutrient loading and habitat/water quality within the estuary under ever-changing conditions.”

His work in Brazil focuses on the Cananéia estuary, primarily modeling the hydrodynamics and the water-quality patterns based on collected data. “Unlike Pleasant Bay, which is influenced significantly by changes in its connection to the open ocean, Cananéia is mainly influenced by a large river that feeds into it. As the first area inhabited in Brazil, and also a very important area for numerous fisheries and with expansive mangrove forests (largest mangrove forest in the state of São Paulo); determining whether or not water quality is negatively influencing the aquatic habitats is important,” Alan said. “While they clearly differ in numerous ways, relating the similarities between these two environments will hopefully help improve understanding of environmental planning and research in other tropical and subtropical estuarine systems.”

Alan’s research will address the watershed-based nutrient loads, which are feeding into these lagoon-type estuaries. “Modeling the water quality of Pleasant Bay as it changes over time will aid in computing what nutrient load the estuary can withstand and how this might change over time. In Cananéia, the collected data and modeling will provide a clearer picture of what is going on within the estuary in terms of circulation and nutrients,” he explained.

His research will benefit the towns bordering the estuary by helping them prepare for various problems associated with nutrient loading. “Good ecological health fosters biodiversity and habitat stability. Poor ecological health leads to habitat degradation and decreased biodiversity and reduced resource value, which can happen as the result of excessive nutrients,” he said. The ultimate goal is to understand the linkage between hydrodynamics, nutrients, and ecological health within both regions.

“The number and density of people living on the world’s coasts is as high as it has ever been. With Pleasant Bay’s barrier beach and inlet changing every decade, its nutrient tolerance, as well as the hydrodynamics within the system, also change. This changing estuary influences the surrounding population,” Alan explained. “Collecting data and modeling these systems will help prepare local communities for future changes in both of these systems and help them develop management actions that might need to occur.”