Nav: Home

Water flea can smell fish and dive into the dark for protection

May 08, 2019

Water fleas - or Daphnia - ensure their survival by reacting to a signal substance of their predators (fish) with flight. The zoologist Meike Anika Hahn from Professor Dr Eric von Elert's research group at the University of Cologne's Institute of Zoology has identified this chemical messenger substance, which the fish releases into the water of lakes. When the water flea detects the substance '5α-cyprinol sulfate' - a bile salt from the fish - it leaves the upper water layers and descends vertically into darker regions. The fish are unable to visually detect their prey there during daytime. This connection between the signal of the predator and the behaviour of its prey has now been published in the scientific journal eLife under the title '5α-cyprinol sulfate, a bile salt from fish, induces diel vertical migration in Daphnia'.

Eric von Elert explains how crucial this communication between fish and planktonic crustacean is to a healthy water environment: 'The water flea is an important link in the lake's ecosystem because it mainly feeds on the constantly growing microalgae. It is crucial for the lake that the Daphnia remain in their natural habitat - the surface of the water - and do not spend the day in the depths where they cannot find any algae. Therefore, it is important to know exactly which signal the water flea reacts to.' Daphnia migrate up to 60 metres up and down the water column every day.

The bile salt in question is vital for the metabolism of fish, which is why, from an evolutionary perspective, they cannot stop releasing it into the water. Now that the substance has been identified, follow-up studies can be carried out to explore whether the fish are actually solely responsible for high concentrations of 5α-cyprinol sulphate. 'It is possible that the substance also comes from contamination from wastewater facilities,' says Professor von Elert.

In aquatic systems such as lakes, an enormous number of chemical reactions and interactions take place that the scientists need to understand the basics of. Especially if an intact system is disturbed from the outside, this can have serious consequences. 'Ultimately, we want to find out how we might be able to restore the biological balance by adding specific natural ingredients', von Elert concludes.

University of Cologne

Related Algae Articles:

Algae and bacteria team up to increase hydrogen production
A University of Cordoba research group combined algae and bacteria in order to produce biohydrogen, fuel of the future
Algae as a resource: Chemical tricks from the sea
The chemical process by which bacteria break down algae into an energy source for the marine food chain, has been unknown - until now.
Left out to dry: A more efficient way to harvest algae biomass
Researchers at the University of Tsukuba develop a new system for evaporating the water from algae biomass with reusable nanoporous graphene, which can lead to cheaper, more environmentally friendly biofuels and fine chemicals.
Algae could prevent limb amputation
A new algae-based treatment could reduce the need for amputation in people with critical limb ischemia, according to new research funded by the British Heart Foundation, published today in the journal npj Regenerative Medicine.
Turning algae into fuel
A team of University of Utah chemical engineers have developed a new kind of jet mixer for creating biomass from algae that extracts the lipids from the watery plants with much less energy than the older extraction method.
The algae's third eye
Scientists at the Universities of Würzburg and Bielefeld in Germany have discovered an unusual new light sensor in green algae.
Could algae that are 'poor-providers' help corals come back after bleaching?
How much of a reef's ability to withstand stressful conditions is influenced by the type of symbiotic algae that the corals hosts?
How some algae may survive climate change
Green algae that evolved to tolerate hostile and fluctuating conditions in salt marshes and inland salt flats are expected to survive climate change, thanks to hardy genes they stole from bacteria, according to a Rutgers-led study.
Feeding plants to this algae could fuel your car
The research shows that a freshwater production strain of microalgae, Auxenochlorella protothecoides, is capable of directly degrading and utilizing non-food plant substrates, such as switchgrass, for improved cell growth and lipid productivity, useful for boosting the algae's potential value as a biofuel.
Algae have land genes
The genome of the algae species Chara braunii has been decoded.
More Algae News and Algae Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#541 Wayfinding
These days when we want to know where we are or how to get where we want to go, most of us will pull out a smart phone with a built-in GPS and map app. Some of us old timers might still use an old school paper map from time to time. But we didn't always used to lean so heavily on maps and technology, and in some remote places of the world some people still navigate and wayfind their way without the aid of these tools... and in some cases do better without them. This week, host Rachelle Saunders...
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at