Nav: Home

New clues to coastal erosion

May 01, 2019

New research has uncovered a missing nutrient source in coastal oceans, which could promote better water quality and sand management on popular beaches.

While the release of nutrients buried in the seabed 'feeds' coastal marine ecosystems, the latest research at Flinders University has found a new physical mechanism which erodes seabed sediment at depths up to 20 metres, well outside (between 10km and 20km) from the surf zone closer to shore.

This powerful natural process that is energetic enough to erode seabed sediment at up to 20 m, also adds to the nutrients stirred and moved by breaking surface waves nearer the beach, according to the new hydrodynamic modelling.

"This new knowledge has significant implications for coastal sediment management practices such as dredging," says Flinders University oceanographer Associate Professor Jochen Kaempf.

The study reveals that major sediment erosion follows from coast-parallel winds in an oceanic situation known as downwelling.

"Such winds trigger a swift coastal current - left-bounded by the coast in the Southern Hemisphere - that is accompanied by a vigorous stirring zone in nearshore waters," Associate Professor Kaempf says.

While this finding explains the high proportion of recycled nutrients in coastal ecosystems, it incidentally also points to a new mechanism of wind-driven sediment drift in coastal oceans that complements the well-known littoral drift in the surf zone.

"Along the Adelaide metropolitan coastline, for example, the wind-driven sediment drift tends to be predominantly southward and opposite to the northward sediment drift in the surf zone," explains Dr Kaempf.

"On the other hand, high turbidity levels following a seabed erosion event negatively impact the health of seagrass beds, and the sudden nutrient release can also trigger potentially harmful toxic algae blooms," says Dr Jochen Kaempf, who also is South Australian branch president of the Australian Meteorological and Oceanographic Society.

Dr Kaempf's latest paper calls for more field research and the development of reliable ocean forecasting models to study and predict the occurrence of such erosion events.
-end-
The paper, Extreme bed shear during coastal downwelling, has been published in Ocean Dynamics (Springer) https://link.springer.com/article/10.1007/s10236-019-01256-4

Flinders University

Related Water Quality Articles:

Lessening water quality problems caused by hurricane-related flooding
June 1 is the start of hurricane season in the Atlantic, and with 2020 predicted to be particularly active, residents in coastal regions are keeping watchful eyes on the weather.
Control of anthropogenic atmospheric emissions can improve water quality in seas
A new HKU research highlighted the importance of reducing fossil fuel combustion not only to curb the trend of global warming, but also to improve the quality of China's coastal waters.
Pharma's potential impact on water quality
When people take medications, these drugs and their metabolites can be excreted and make their way to wastewater treatment plants.
Study: Your home's water quality could vary by the room -- and the season
A study has found that the water quality of a home can differ in each room and change between seasons, challenging the assumption that the water in a public water system is the same as the water that passes through a building's plumbing at any time of the year.
Researchers create new tools to monitor water quality, measure water insecurity
A wife-husband team will present both high-tech and low-tech solutions for improving water security at this year's American Association for the Advancement of Science (AAAS) annual meeting in Seattle on Sunday, Feb.
How anti-sprawl policies may be harming water quality
Urban growth boundaries are created by governments in an effort to concentrate urban development -- buildings, roads and the utilities that support them -- within a defined area.
China's inland surface water quality significantly improves
A new study shows that China's inland surface water quality improved significantly from 2003-2017, coinciding with major efforts beginning in 2001 to reduce water pollution in the country.
Studying water quality with satellites and public data
The researchers built a novel dataset of more than 600,000 matchups between water quality field measurements and Landsat imagery, creating a 'symphony of data.'
How to improve water quality in Europe
Toxic substances from agriculture, industry and households endanger water quality in Europe -- and by extension, ecosystems and human health.
Revolutionizing water quality monitoring for our rivers and reef
New, lower-cost help may soon be on the way to help manage one of the biggest threats facing the Great Barrier Reef.
More Water Quality News and Water Quality Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Biology Of Sex
Original broadcast date: May 8, 2020. Many of us were taught biological sex is a question of female or male, XX or XY ... but it's far more complicated. This hour, TED speakers explore what determines our sex. Guests on the show include artist Emily Quinn, journalist Molly Webster, neuroscientist Lisa Mosconi, and structural biologist Karissa Sanbonmatsu.
Now Playing: Science for the People

#569 Facing Fear
What do you fear? I mean really fear? Well, ok, maybe right now that's tough. We're living in a new age and definition of fear. But what do we do about it? Eva Holland has faced her fears, including trauma and phobia. She lived to tell the tale and write a book: "Nerve: Adventures in the Science of Fear".
Now Playing: Radiolab

The Wubi Effect
When we think of China today, we think of a technological superpower. From Huweai and 5G to TikTok and viral social media, China is stride for stride with the United States in the world of computing. However, China's technological renaissance almost didn't happen. And for one very basic reason: The Chinese language, with its 70,000 plus characters, couldn't fit on a keyboard.  Today, we tell the story of Professor Wang Yongmin, a hard headed computer programmer who solved this puzzle and laid the foundation for the China we know today. This episode was reported and produced by Simon Adler with reporting assistance from Yang Yang. Special thanks to Martin Howard. You can view his renowned collection of typewriters at: antiquetypewriters.com Support Radiolab today at Radiolab.org/donate.