Michael DeWitt
Michael DeWitt is a senior software engineer at Google. He joined the Google Earth Engine team in 2013, where he has developed image processing algorithms, data management tools, and computational pipelines for the scientific satellite computation platform.
His primary research interest is the quantification of ecological change, but he is also keen on human vision (particularly for data visualization), quantum computing, and hiking. Michael holds degrees in mathematics and computer science from the University of Maryland, College Park.
His primary research interest is the quantification of ecological change, but he is also keen on human vision (particularly for data visualization), quantum computing, and hiking. Michael holds degrees in mathematics and computer science from the University of Maryland, College Park.
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The global distribution and trajectory of tidal flats
Nicholas J. Murray
Stuart R. Phinn
Renata Ferrari
Renee Johnston
Mitchell B. Lyons
David Thau
Richard A. Fuller
Nature, 565 (2019), pp. 222-225
Preview abstract
Increasing human populations around the global coastline have caused extensive loss, degradation and fragmentation of coastal ecosystems, threatening the delivery of important ecosystem services. As a result, alarming losses of mangrove, coral reef, seagrass, kelp forest and coastal marsh ecosystems have occurred. However, owing to the difficulty of mapping intertidal areas globally, the distribution and status of tidal flats—one of the most extensive coastal ecosystems—remain unknown. Here we present an analysis of over 700,000 satellite images that maps the global extent of and change in tidal flats over the course of 33 years (1984–2016). We find that tidal flats, defined as sand, rock or mud flats that undergo regular tidal inundation, occupy at least 127,921 km² (124,286–131,821 km², 95% confidence interval). About 70% of the global extent of tidal flats is found in three continents (Asia (44% of total), North America (15.5% of total) and South America (11% of total)), with 49.2% being concentrated in just eight countries (Indonesia, China, Australia, the United States, Canada, India, Brazil and Myanmar). For regions with sufficient data to develop a consistent multi-decadal time series—which included East Asia, the Middle East and North America—we estimate that 16.02% (15.62–16.47%, 95% confidence interval) of tidal flats were lost between 1984 and 2016. Extensive degradation from coastal development, reduced sediment delivery from major rivers, sinking of riverine deltas increased coastal erosion and sea-level rise signal a continuing negative trajectory for tidal flat ecosystems around the world. Our high-spatial-resolution dataset delivers global maps of tidal flats, which substantially advances our understanding of the distribution, trajectory and status of these poorly known coastal ecosystems.
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