Featured Research

from universities, journals, and other organizations

Deep sedimentation of acantharian cysts: A reproductive strategy?

Date:
March 8, 2010
Source:
National Oceanography Centre, Southampton (UK)
Summary:
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.

Acantharian cyst.
Credit: Patrick Martin SOES/NOCS

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.


Story Source:

The above story is based on materials provided by National Oceanography Centre, Southampton (UK). Note: Materials may be edited for content and length.


Journal Reference:

  1. 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)

Cite This Page:

National Oceanography Centre, Southampton (UK). "Deep sedimentation of acantharian cysts: A reproductive strategy?." ScienceDaily. ScienceDaily, 8 March 2010. <www.sciencedaily.com/releases/2010/03/100308102200.htm>.
National Oceanography Centre, Southampton (UK). (2010, March 8). Deep sedimentation of acantharian cysts: A reproductive strategy?. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2010/03/100308102200.htm
National Oceanography Centre, Southampton (UK). "Deep sedimentation of acantharian cysts: A reproductive strategy?." ScienceDaily. www.sciencedaily.com/releases/2010/03/100308102200.htm (accessed July 31, 2014).

Share This




More Plants & Animals News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) — Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) — Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) — At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) — The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



      Save/Print:
      Share:  

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile iPhone Android Web
      Follow Facebook Twitter Google+
      Subscribe RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins