New carnivorous harp sponge discovered in deep sea

November 20, 2012 by  
Filed under Secrets of the Ocean

A blog by Scientific American.

You may remember the Monterey Bay Aquarium Research Institute (MBARI) from such discoveries as the Yeti crab, the squid with elbows and my personal favourite, the pigbutt worm, and now they’re back with footage of a new species of carnivorous sponge.

Seventeen years ago, Jean Vacelet and Nicole Boury-Esnault from the Centre of Oceanology at France’s Aix-Marseille University provided the first real evidence that a sponge could be more than, well, a sponge. They had discovered a new species of deep-sea sponge living in the unusual setting of a shallow Mediterranean sea cave, the inside of which mimicked the conditions of its usual habitat more than a kilometre below the surface. This allowed the researchers an unprecedented view of the sponge’s eating habits, and they watched as it snared its prey of small fish and crustaceans instead of absorbing bacteria and organic particles through their bodies, like most other sponge species do – including ones living in the very same cave.

Vacelet and Boury-Esnault’s sponges were of the Asbestopluma genus and belonged to the Cladorhizidae family of carnivorous demosponges – the class that contains over 90% of the world’s sponges. Since reporting their discovery in a 1995 issue of Nature, 24 new species of cladorhizid sponges, including the incredible ping-pong tree sponge (see below), have also been discovered. Yet due to the difficulty of studying their behaviour at such incredible depths, researchers have had little opportunity to describe essential aspects of their lives, particularly how they reproduce.

Chondrocladia, or ping-pong, sponge.  MBARI

Chondrocladia, or ping-pong, sponge. MBARI

Which is where MBARI’s remotely operated vehicles (ROVs) Tiburon and Doc Ricketts, come in. Using these deep-diving vessels, a team of researcher s led by Senior Research Technician Lonny Lundsten discovered a species of harp sponge called Chondrocladia lyra off the coast of California, at depths of 3316–3399m.

As Mr_Skeleton pointed out on Reddit this week, this sponge doesn’t look like it could clean anything. But it can catch prey, envelope it in membrane and digest it whole, so it certainly has other priorities. Based on footage of several individuals and two large, fragmentary specimens brought up by the ROVs, Lundsten’s team described how the vertical branches and horizontal stolons that make up the sponge’s basic harp-like structure, called a vane, are covered in barbed hooks and spines. They found that a number of crustacean prey were passively ensnared on these branches thanks to the Velcro-like hooks and then aggressively enclosed in a cavity to be dismembered into small, digestible particles, which provided direct evidence of the species’ carnivorous appetites.

The vertical branches of the harp sponge are tipped by swollen terminal balls containing packets of sperm.

The vertical branches of the harp sponge are tipped by swollen terminal balls containing packets of sperm.  MBARI

The vertical branches of the harp sponge are tipped by swollen terminal balls containing packets of sperm. MBARI

C. lyra can grow up to 37cm long – impressive for a sponge – and are anchored to the sea-floor by a structure called a rhizoid, which looks like a root system. They can have 1-6 vanes, each supporting a number of equidistant vertical branches, and each of these end in swollen terminal balls. According to the researchers, these terminal balls produce condensed packets of sperm called spermatophores, which are released into the surrounding water in the hopes of fertilising other harp sponges in the area. Each C lyra sponge also has an egg development area around the mid-point of the branches, and when the spermatophores make contact, these areas swell up as the eggs are fertilised and begin to mature.

The team suggests that the structure of the harp sponge is designed to ensure that they catch the most prey possible, and also maximise their chances of catching spermatophores from other harp sponges.

“Video footage taken as the ROVs approached specimens of C. lyra provided information about the biological diversity of the areas in which the sponges live,” the researchers added in their report in the current issue of Invertebrate Biology. “Among the coexisting invertebrates were unidentified sea anemones; the soft coral Anthomastus robustus, members of several species of sea pens; and the sea cucumber Paelopadites confundens, as well as another sea cucumber in the family Elipidiidae.”

Article source: http://www.nature.com/news/new-carnivorous-harp-sponge-discovered-in-deep-sea-1.11789

Creatures of deep new to scientists

November 20, 2012 by  
Filed under Secrets of the Ocean

Weird underwater discoveries such as an egg-eating Australian sea serpent and a strikingly coloured worm named after Star Wars‘ Yoda could carry on for decades to come, with new research estimating that up to one third of species remain undiscovered.

A study co-led by a University of Auckland expert and published today in international journal Current Biology calculated there were fewer than one million marine species on the planet, lower than some previous estimates. The number undiscovered likely amounts to a third of all species.

Hot spots for new finds included deep sea ecosystems and those in tropical areas, said Associate Professor Mark Costello from the University of Auckland, who co-led the research with Ward Appeltans of Flanders Marine Institute and the Intergovernmental Oceanographic Commission of Unesco.

“If we look at the number of undescribed species and samples from around the world, especially deep sea and tropical areas, the average over 100 studies was that about 30 per cent of those new species were new to science,” he told the Herald.

Easier identification, better technology and more scientists would boost the rate of discovery.

“It’s likely it will get harder and harder to find the rarer things, but it also gets more exciting.”

Bizarre species discovered within the past year included Yoda purpurata, which had features resembling the Jedi master’s large sagging ears, a crimson shrimp found at a depth of 2600m beneath the Norwegian Sea, and an odd-looking bristle worm discovered 1600m below the northeast Pacific.

“Knowing how many species there are in our oceans, and describing them, is vital for science and conservation for several reasons,” Professor Costello said.

“Species are the most practical measure for distinguishing habitats and tracking progress in exploring the earth’s biodiversity.

“They are as fundamental to biology as elements are to chemistry and particles to physics.

“So failure to consider all species in an ecosystem is analogous to an accountant ignoring items of inventory in a company’s stock.”

Better understanding of what species exist enabled more accurate estimates of extinction rates through habitat loss, while having a “master list” of species’ names was essential for quality assurance.

Research efforts have been boosted by the World Register of Marine Species – an open-access, online database that has received contributions from almost 300 scientists from 32 countries.

The study supports previous research by Professor Costello and colleagues, which used statistical modelling and an earlier version of the register to reach a similar estimate of the number of species on earth and in the oceans. It is also the culmination of 14 years’ work for Professor Costello, who began a European register of marine species in 1997 that expanded until the world register was initiated in 2006.

OCEANS STILL TO GIVE UP THEIR INHABITANTS

Around 226,000 species have been described by science and as many as 72,000 more are in collections awaiting description – yet hundreds of thousands more may still be waiting for discovery in our oceans.

The rate of discovery is, however, increasing, with an unprecedented 20,000 new marine species described in the past decade alone, suggesting that most marine species will be discovered this century.

Earlier estimates of ocean diversity had relied on expert polls based on extrapolations from past rates of species descriptions and other measures.

Those estimates varied widely, suffering because there was no global catalogue of marine species, and a new study gauging a more accurate figure canvassed 120 of the world’s top experts on the taxonomy, or classification, of marine species.

Mammals, birds, reptiles, insects and larger plants were some of the best-described groups of marine species to date.

Many of the species yet to be discovered will come from among the smaller crustaceans, molluscs, algae, worms, and sponges.

By Jamie Morton Jamienzherald Email Jamie

Article source: http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10847735

Growing seaweed can solve ocean acidification and solve global food supply

December 22, 2010 by  
Filed under Global Warming

22 Dec 2010
Unit: Wageningen UR

Large-scale cultivation of sea lettuce can help reduce acidification of the oceans. And help solve the global food supply problem to boot.

This idea, presented by Wageningen biologist Ronald Osinga, came as a surprise to delegates at the international coral symposium held in Wageningen last week. The symposium was an initiative by the International Society for Reef Studies (ISRS) and focused on the effects of climate change on coral reefs. Acidification of the oceans is one of the problems, and corals are highly sensitive to it. They become bleached and the calcium they contain dissolves.

Marine horticulture
But this does not have to happen, says marine biologist Osinga. On the closing day of the symposium he proposed a solution: sea lettuce (ulva lactuca). As it grows, this marine plant lowers the acidity of water. What is more, it is edible. Osinga and his colleagues have calculated that a ‘marine garden’ of 180,000 square kilometres could provide enough protein for the entire world population. A sea lettuce bed of such gigantic proportions would raise the pH (acidity level) of the Mediterranean Sea by one tenth. That may not seem much, but according to Osinga, it would be enough to compensate for the rise in acidity that started with the industrial revolution.

Fish farming
Linking the cultivation of sea lettuce with fish farming would create a closed food cycle, says Osinga. The waste products of the fish would nourish the sea lettuce. Osinga: ‘Offshore fish-farming is a massive polluter. It’s much better if you can recycle these nutrients. There is a lot of interest nowadays in this sort of integrated concept.’

BES
Osinga and his University of Amsterdam colleague Jaap Kaandorp brought the symposium to Wageningen in order to draw attention to Dutch coral research. Wageningen UR plays a modest role in this research, but that may be about to change through the accession of the ‘BES’ islands (Bonaire, St. Eustatius and Saba) in the Caribbean to the Netherlands. But that is a separate issue, says Osinga, and not the reason for the symposium. ‘It’s a coincidence. But a useful one, with all the attention to the coral reefs around the BES islands.’ Three hundred scientists from all over the world took part in the symposium. / Roelof Kleis


The above article was written by the editorial staff of Resource, the bi-weekly newspaper for Wageningen University and Research centre. For more information, contact the press and science information officer of Wageningen UR, e-mail: pers.communicatie@wur.nl or the editorial staff of Resource, e-mail: resource@wur.nl. See the archived articles at resource.wur.nl

Article source: http://nextbigfuture.com/2010/12/growing-seaweed-can-solve-ocean.html