Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Deep sedimentation of acantharian cysts -- a reproductive strategy?

Acantharian cyst sedimentation

Spore-like reproductive cysts of enigmatic organisms called acantharians rapidly sink from surface waters to the deep ocean in certain regions, according to new research. Scientists suspect that this is part of an extraordinary reproductive strategy, which allows juveniles to exploit a seasonal food bonanza.

The research shows that deep sedimentation of cysts during the spring delivers significant amounts of organic matter to the ocean depths, providing a potential source of nutrients for creatures of the deep.

"Although acantharians are known to contribute to organic matter transport at shallower depths, we were amazed to discover a high flux of their spore-like reproductive cysts in the deep ocean," says PhD student Patrick Martin of the University of Southampton's School of Ocean and Earth Science based at the National Oceanography Centre, Southampton.

Cysts were found in sediment trap samples recovered from a depth of 2000 metres in the Iceland Basin, a deep region of the Atlantic Ocean south of Iceland. The traps were deployed in 2006 from the Royal Research Ship Discovery to collect sinking organic-rich particles. Such particles comprise part of the biological carbon pump, whereby carbon 'fixed' from carbon dioxide by photosynthetic organisms in sunlit surfaces waters is exported to the deep ocean.

Although single celled and known mainly to specialists, acantharians are globally distributed and often very abundant. Adults are found mainly in the top 300 metres, where symbiotic algae living within them contribute to primary productivity through photosynthesis.

Uniquely, the spiny skeletons and cyst shells of acantharians are composed of crystalline strontium sulphate, known as celestite, precipitated from seawater in the upper ocean. Celestite is the densest known marine biomineral, but it readily dissolves in seawater, thereby releasing strontium back into the seawater.

"Celestite ballast causes rapid sinking. The cysts we found in the Iceland Basin are larger than reported from other regions, up to a millimetre long, and thus sink faster. We believe that this allows them to reach considerable depths before their celestite shells dissolve," says Patrick Martin.

This is consistent with changes in seawater strontium concentration with depth, measured by other scientists in the Iceland Basin. Similar measurements suggest that acantharian cysts in the subarctic Pacific may also sink to great depths.

Acantharian cyst flux in the Iceland Basin was restricted to April and May. It contributed up to around half the particulate organic matter found in the traps during the two weeks of highest cyst flux, albeit with considerable variation between samples.

Evidence suggests that, at high latitudes, rapid, deep sedimentation of acantharian cysts recurs each spring. The cysts sink to depth to release gametes and then die. Juveniles may then descend to the seafloor before ascending to the surface as they mature.

The deep flux of cysts coincides with the spring bloom of phytoplankton, the tiny marine algae that dominate primary production in sunlit surface waters.

"We speculate that this is part of a reproductive strategy allowing juveniles to feed off the remains of phytoplankton, 'phytodetritus', that rapidly sinks to the seafloor following the spring bloom," says Patrick Martin.

In that case, deep sedimentation of cysts could be regarded as an adaptation to life in highly seasonal environments, leading to the expectation that the phenomenon should occur in other high-latitude ocean regions.


Martin, P., Allen, J. T., Cooper, M. J., Johns, D. G., Lampitt, R. S., Sanders, R. & Teagle, D. A. H. Sedimentation of acantharian cysts in the Iceland Basin: Strontium as a ballast for deep ocean particle flux, and implications for acantharian reproductive strategies. Limnol. Oceanogr. 55(2), 604-614 (2010).

This study was funded by the Natural Environment Research Council, UK, as part of the Oceans 2025 program.

The authors are Patrick Martin, John Allen, Matthew Cooper, Richard Lampitt, Richard Sanders and Damon Teagle (all of NOCS), and David Johns (Sir Alister Hardy Foundation for Ocean Science, Plymouth).

The National Oceanography Centre, Southampton (NOCS) is the UK's focus for ocean science. It is one of the world's leading institutions devoted to research, teaching and technology development in ocean and Earth science. Over 500 research scientists, lecturing, support and seagoing staff are based at the Centre's purpose-built waterside campus in Southampton along with over 700 undergraduate and postgraduate students.

The NOCS is a collaboration between the University of Southampton and the Natural Environment Research Council (NERC). The NERC royal research ships RRS James Cook and RRS Discovery are based at NOCS, as is the National Marine Equipment Pool which includes Autosub and Isis, two of the world's deepest diving research vehicles.

From April 1, 2010, NERC-managed activity at the NOCS joins forces with the Proudman Oceanographic Laboratory in Liverpool to form a new, national research organisation - the National Oceanography Centre (NOC). The NOC will work in partnership with the UK marine research community to deliver integrated marine science and technology from the coast to the deep ocean. The University of Southampton will be one of the NOC's two hosting partners, the other being the University of Liverpool.

Dr Rory Howlett | EurekAlert!
Further information:

More articles from Earth Sciences:

nachricht Oasis of life in the ice-covered central Arctic
24.10.2016 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht Receding glaciers in Bolivia leave communities at risk
20.10.2016 | European Geosciences Union

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Oasis of life in the ice-covered central Arctic

24.10.2016 | Earth Sciences

‘Farming’ bacteria to boost growth in the oceans

24.10.2016 | Life Sciences

Light-driven atomic rotations excite magnetic waves

24.10.2016 | Physics and Astronomy

More VideoLinks >>>