Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Time to rise and shine

14.07.2017

Genetic clocks in zooplankton species regulate what is likely the largest daily movement of biomass worldwide

The copepod species Calanus finmarchicus schedules its day using a genetic clock that works independently of external stimuli. The clock shapes the copepod’s metabolic rhythms and daily vertical migration.


Calanus finmarchicus

Photo: David Pond / Scottish Associatio

This in turn have an enormous influence on the entire food web in the North Atlantic, where Calanus finmarchicus is a central plankton species. Wherever the high-calorie copepod is, determines where its predator species are. The results of the study will be published in the journal Current Biology.

Day after day, our world’s oceans are home to a massive vertical migration: at dusk, countless plankton species, like copepods and krill, rise to the surface, where they gorge themselves on single-celled algae that can only thrive where there is sufficient sunlight. The cover of night offers the plankton protection from predators like fish, which need light to hunt.

When dawn approaches, they sink back into the dark depths, where they can hide from their predators throughout the day – completing a cycle that likely represents the largest daily movement of biomass on the entire planet. Though this phenomenon was first discovered over a century ago, researchers are still working to decipher which signals these marine organisms use to decide when to rise and when to descend.

Light seems to be an important factor – yet this migration also continues during the long polar night and in the deep sea, where hardly any light is detectable. Experts at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have now shown that the copepod species Calanus finmarchicus possesses an internal genetic clock that produces a specific 24-hour rhythm, independent of ambient conditions. Light is only needed in order to occasionally “reset” the clock. “This clock regulates the copepods rhythm of metabolic activity as well as their daily vertical migration,” explains first author Sören Häfker.

Working together with colleagues from the University of Oldenburg and the Scottish Association for Marine Science, he conducted a detailed study of this important plankton species’ internal clock mechanism and compared the daily migration with the rhythm of the genetic clock. As Häfker recalls, “We were amazed to see how precisely the genetic clock maintained its 24-hour rhythm without any external stimuli, and that we found the same rhythm under controlled laboratory conditions as we did in the natural habitat of Loch Etive, Scotland.”

In their natural environment, the copepods can cover several hundred metres in their daily migrations; intriguingly, the researchers were able to confirm the same movement pattern in laboratory experiments. They began by simulating a natural day-and-night rhythm, and then kept the animals in constant darkness for several days. Under these conditions, they measured oxygen consumption (as an indicator of metabolic activity), the vertical migration behaviour, and the activity levels of different “clock genes”.

What they found: in the roughly one-metre-tall test tanks, the rhythmic vertical migration continued as it did in the field, even in constant darkness. This behaviour shows that migration is regulated by the genetic clock. As a result, the tiny crustaceans can predict the daily cycle, allowing them to e.g. withdraw to deeper water layers before there is enough sunlight for predators to find them.

The copepod Calanus finmarchicus builds up large fat reserves in its body, making it an appealing source of food for many larger animals. As such, its daily migration is extremely important for the ecosystem – especially because, due to global warming, the distribution of many marine species has shifted closer to the poles.

However, the duration of daylight varies much more throughout the year near the poles, which raises the question of whether the copepods’ internal clocks can cope with these extreme conditions. As Sören Häfker concludes, “Only if we understand how genetic clocks function and how they affect the life in the oceans, we will be able to predict how marine species will respond to future changes in their environment – for example, due to climate change – and what consequences this will have for marine ecosystems.”

Notes for Editors

The study will be published under the following title in Current Biology:
N. Sören Häfker, Bettina Meyer, Kim S. Last, David W. Pond, Lukas Hüppe, Mathias Teschke: „Circadian Clock Involvement in Zooplankton Diel Vertical Migration“. DOI: 10.1016/j.cub.2017.06.025

Your scientific contact partner at the Alfred Wegener Institute is: Sören Häfker (Tel: +49 (0)471 4831 - 2360; E-Mail: soeren.haefker(at)awi.de)

At the AWI’s Communications and Media Relations department, Sebastian Grote (Tel: +49 (0)471 4831 - 2006; E-Mail: sebastian.grote(at)awi.de) will be pleased to help you with any questions.

The Alfred Wegener Institute pursues research in the Arctic, Antarctic and the oceans of the middle and high latitudes. It coordinates polar research in Germany, while also providing essential infrastructure for the international scientific community, including the research icebreaker Polarstern and stations in the Arctic and Antarctic. The Alfred Wegener Institute is one of the 18 Research Centres of the Helmholtz Association, the largest scientific organisation in Germany.

Ralf Röchert | idw - Informationsdienst Wissenschaft
Further information:
http://www.awi.de/

More articles from Life Sciences:

nachricht Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology

nachricht Migrating Cells: Folds in the cell membrane supply material for necessary blebs
23.11.2017 | Westfälische Wilhelms-Universität Münster

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New proton record: Researchers measure magnetic moment with greatest possible precision

High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons

The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Lightning, with a chance of antimatter

24.11.2017 | Earth Sciences

A huge hydrogen generator at the Earth's core-mantle boundary

24.11.2017 | Earth Sciences

Scientists find why CP El Niño is harder to predict than EP El Niño

24.11.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>