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Plankton is not just whale food

Scientists  unveiled the most comprehensive analysis ever undertaken of the world’s ocean plankton, the tiny organisms that serve as food for marine creatures such as the blue whale, but also provide half the oxygen we breathe. The researchers spent 3-½ years aboard the schooner Tara, taking 35,000 samples of plankton from 210 sites globally, determining the distribution of the organisms, tracking how they interact with one another and carrying out genetic analyses.

Plankton include microscopic plants and animals, fish larvae, bacteria, viruses and other microorganisms that drift in the oceans.

“Plankton are much more than just food for the whales,” said Chris Bowler, a research director at France’s National Center for Scientific Research, and one of the scientists involved in the study published in the journal Science. “Although tiny, these organisms are a vital part of the Earth’s life support system, providing half of the oxygen generated each year on Earth by photosynthesis and lying at the base of marine food chains on which all other ocean life depends.”

The scientists conducted the largest DNA sequencing effort ever done in ocean science, pinpointing around 40 million plankton genes, most previously unknown. Much of the plankton was more genetically diverse than previously known. However, the genetic diversity of marine viruses was much lower than anticipated.

By removing carbon dioxide from the atmosphere and converting it into organic carbon via photosynthesis, plankton provide a buffer against the increased carbon dioxide being generated by the burning of fossil fuels, Bowler said.

Read more (via reuters.com)

Images (via scientificamerican.com)

Britney Spears invented dogs in 2002 through a process now referred to as “selective breeding”. She began in 1996 when she bred her two short-haired guinea pigs, Coco and Buddy. Year after year, Spears would breed the largest and most distinctive guinea pigs from each litter and eventually broke the world record for the largest guinea pig (Jimbo, 6.2 kg, 1999). Over the course of 6 years and 8 generations, a significant genetic mutation occurred and the first dog (Bit Bit) was born. Spears continues to breed dogs to this day and produces beloved pets for families all around the world.

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Brown palm civet (Paradoxurus jerdoni)

Brown palm civet is a civet endemic to the Western Ghats of India. There are two subspecies. They are nocturnal. The body weight of the males ranges from 3.6 kg to 4.3 kg, head and body length 430 mm to 620 mm, and tail length from 380 to 530 mm. The brown palm civet is predominantly frugivorous. Fruits form a large proportion (97 per cent) of its diet and more than 53 native and four introduced species of plants have been recorded. The brown palm civet is solitary. They rest during the day in day-bed sites, such as tree hollows, canopy vine tangles, Indian giant squirrel nests and forks of branches. The day-bed trees are large and are usually in dense mature forest stands with high canopy connectivity. They sometimes rest in the night in open branches.

photo credits: wiki, Kalyanvarma, Kalyanvarma

Bacteria cooperate to repair damaged siblings

A University of Wyoming faculty member led a research team that discovered a certain type of soil bacteria can use their social behavior of outer membrane exchange (OME) to repair damaged cells and improve the fitness of the bacteria population as a whole.

Daniel Wall, a UW associate professor in the Department of Molecular Biology, and others were able to show that damaged sustained by the outer membrane (OM) of a myxobacteria cell population was repaired by a healthy population using the process of OME. The research revealed that these social organisms benefit from group behavior that endows favorable fitness consequences among kin cells.

Wall says, to the research group’s knowledge, this is the first evidence that a bacterium can use cell-content sharing to repair damaged siblings.

“It is analogous to how a wound in your body can be healed,” Wall says. “When your body is wounded, your cells can coordinate their functions to heal the damaged tissue.”

Wall was the senior and corresponding author on a paper, titled “Cell Rejuvenation and Social Behaviors Promoted by LPS Exchange in Myxobacteria” that was published in the May 18 online issue of the Proceedings of the National Academy of Sciences (PNAS).

(Image: Michiel Vos) - Antisocial Behavior in Cooperative Bacteria (or, Why Can’t Bacteria Just Get Along?). PLoS Biology Vol. 3/11/2005, e398 doi:10.1371/journal.pbio.0030398

Some 100,000 Myxococcus xanthus cells amassed into a fruiting body with spores.

Octopus’s skin detects light the same way its eyes do

Octopuses have a well-known ability to change the color and texture of their skin in order to blend in with their environment or to communicate with other organisms. They are able to do this because of special pigmented organs in their skin, called chromatophores, which receive signals from the animal’s eyes and then expand and contract as needed to change the skin’s appearance. A new study shows that the octopus’s eyes are not the only way that the chromatophores receive these signals, however: octopus skin can change its appearance with no input from the eyes at all.

Researchers at UC Santa Barbara studied the California two-spot octopus (Octopus bimaculoides) and found that its skin changed color when exposed to white light as a result of the chromatophores in the skin contracting, even with no sensory input from the eyes. Further experiments showed that the chromatophores responded the quickest to blue light. This process, called light-activated chromatophore expansion, shows that the chromatophores and light sensors are linked within the skin and do not rely on input from the central nervous system. The skin could not sense light with the same detail as the eyes and brain, with its responses being limited to changes in brightness, but the changes were undeniably there.

Researchers dug deeper and found that sensory neurons in the octopus’s skin contained rhodopsin, a light-sensitive opsin protein found in the octopus’s eyes. This reveals a heretofore-unknown evolutionary adaptation in which cellular mechanisms for light detection in octopuses’ eyes have been adopted by their skin as well.

Other marine molluscs have light-sensing skin, but researchers are not sure if that is the result of opsins or other adaptations. If other molluscs’ skin also uses these proteins to change appearance, researchers hope to discover whether the similar adaptations evolved independently or from a common ancestor.

  • Based on materials originally provided by UC Santa Barbara
  • Journal reference: M. D. Ramirez, T. H. Oakley. Eye-independent, light-activated chromatophore expansion (LACE) and expression of phototransduction genes in the skin of Octopus bimaculoides. Journal of Experimental Biology, 2015; 218 (10): 1513 DOI:10.1242/jeb.110908
  • Image: A California two-spot octopus (Credit: Partial Pressure Production, via marinebio.org)
  • Submitted by volk-morya

Rembrandt, The Anatomy Lesson of Dr. Nicholaes Tulp, 1632, oil on canvas, 170 x 217 cm, Mauritshuis, The Hague. Source

In this piece, Rembrandt gives us an up-close encounter of a group of medical professionals being taught the complex anatomical structure of the human body by the Dr. Nicholaes Tulp. The corpse is believed to be the executed criminal Aris Kindt, who was pronounced guilty for armed robbery.

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Lime Nail Gall

A ‘gall’ on a leaf is a microhabitat of a small herbivorous organism; these nail-shaped galls on a Linden (Tillia sp.) are caused by Eriophyes tiliae, a mite.

This mite exclusively lives on Lindens, spending winters in the bark of the tree, and crawling out to the leaves to feel on sap in the summers.

Only 2 mm long, E. tillae lives inside the galls (sometimes called shielings or huts) for the duration of the growing season. The mites are protected from predators, and do little to no harm to the tree itself.

The galls aren’t ‘built’ by the insect, so much as they result from a chemical reaction in the plant tissues that is induced and controlled by the mite, which affects the tissue to blow up in colourful tubes.

Deepwater spill killed dolphins in record numbers

Scientists are now confident the abnormally high numbers of bottlenose dolphins (Tursiops truncatus) that have died—and continue to die—in the oil spill area are suffering from ailments caused by oil byproducts. Although researchers don’t have exact numbers of how many dolphins perished following the spill, they’ve found 1281 stranded and dead between 30 April 2010 and 17 May 2015—the highest number ever recorded in the Gulf of Mexico. Barataria Bay, Louisiana, was particularly hard hit by the spill. Half of the dead dolphins found in this region between June 2010 and November 2012 had a thin adrenal gland cortex—a key indicator of an ailment known as adrenal insufficiency which often leads to death in dolphins, particularly among those who are pregnant. This same lesion was found in one of every three dolphins examined in oil-contaminated areas across Louisiana, Mississippi, and Alabama, the team reports in PLOS ONE. 

Plankton in the news!

Studying microscopic organisms teaches us critical lessons about our world. The research schooner Tara, which has been traveling the oceans since 2009, is greatly increasing our knowledge of tiny marine organisms, including plankton. This week’s issue of Science magazine features the Tara’s research on plankton and other marine organisms, with lots of beautiful photos! Read more about the Tara here and here. The Exploratorium’s biology lab is also collecting plankton data and photographs from our home at Pier 15, and contributing a piece to the global plankton puzzle.