Menu change for corals in warming reefs

March 26, 2019, University of Queensland

Warming coral reefs are losing their capacity to feed themselves from sunlight, making nutritious deep ocean water critical for their survival, according to a University of Queensland study.

UQ Ph.D. candidate Veronica Radice analysed coral samples from the Maldives to find out what corals were feeding on in a remote atoll system.

"Corals depend on different sources of nutrition including sunlight and nutrients in the water," she said.

"What many people don't realise is that corals have algae living in their tissue, which allows them to photosynthesise sunlight, giving the coral some plant-like properties.

"However, ocean warming due to climate change is causing these corals to be stressed, which makes them lose this nutritional source from their symbiotic algae.

"So we thought it was important to see what other food sources corals were relying on."

Ms Radice and her colleagues collected fragments of three species of coral from reefs at 10 metres and 30 metres depths in the Maldives.

"We separated the tissue of the symbiotic algae from its coral host tissue, and samples were then prepared for isotopic analysis," she said.

"This allowed us to break apart a coral's diet and nutrients, looking at the ratios of different isotopes – for example, carbon or nitrogen – giving us clues to where these nutrients might come from."

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Rats: Sniff and track, or run and scan?

Date: November 24, 2015

Source: Tata Institute of Fundamental Research

It's dinnertime, and the smell of delicious food makes your tummy rumble. However, it's dark because of a powercut and you can't see very clearly. Should you try to 'follow your nose' to locate food? Or should you simply guess and peek into the kitchen, or the dining room or the veranda -- the likeliest places for dinner to be served? A recent study shows that the latter method -- dubbed 'run-and-scan' -- may actually be more efficient in finding your target than just following your nose.

Research by Urvashi Bhattacharyya and Upinder Bhalla from the National Centre for Biological Sciences (NCBS), Bangalore, reveals that while searching in a familiar area with limited choices, a run-and-scan strategy is more efficient than a tracking strategy. In a recently published paper in the journal eNeuro, Bhattacharyya and Bhalla used rats to study how animals choose navigational strategies when presented with an odour signal.

Read on ...

Elephants may use trunks like 'leaf blowers' to obtain inaccessible food

Date:  November 5, 2015

Source:  BioMed Central

Two captive elephants blast air through their trunks to grasp hard-to-reach food, suggests an initial study published today in Springer's journal Animal Cognition. This behaviour, studied in a zoo population of Asian elephants (Elephas maximus), is altered according to the distance to the food, which may indicate advanced mental ability and awareness of their physical environment.

Previous observations, including by Charles Darwin, have suggested that elephants may manipulate their breath to reach inaccessible food, but there has been limited opportunity to test this behaviour in an experimental setting. To investigate whether elephants use this behaviour to achieve goals, scientists from SOKENDAI (The Graduate University for advanced studies) and Kyoto University studied two female captive elephants, Mineko and Suzuko, at Kamine Zoo in Japan. They predicted that the further away a piece of food was, the more frequently the elephants would blast it with air to bring it near to them.

To test this theory, the team of researchers digitally mapped out a grid in a ditch in the elephants' enclosure, placed food in various locations on the 'virtual' grid, and filmed the elephants trying to reach it. They used five different types of food: apple, bamboo, hay, fallen leaves and potatoes. The researchers recorded the elephants' behaviour over 32 days, spilt into 128 trials; a trial began when it was audible that the elephants had started blowing and finished when they grasped the food or gave up. They then analysed the frequency and duration of blowing, the position and shape of the elephants' trunks, and their success and skill by tracking the movement of food across the grid.

Continued …

Lowly Jellyfish Uses High-Tech Strategy to Find Food

By Elizabeth Palermo, Staff Writer | August 05, 2014 07:02pm ET

The barrel jellyfish, isn't just the largest jelly found in the waters around the United Kingdom, it's also one of the animal kingdom's most strategic searchers, according to a new study.

To locate the best possible meal in the vast waters of its marine habitat, the barrel jellyfish (Rhizostoma octopus) uses a strategy most commonly associated with the world's fastest supercomputers — an approach known as fast simulated annealing.

For mathematicians, fast simulated annealing is an algorithm, implemented by a supercomputer, which can find optimal solutions to complex problems in a relatively short amount of time. For jellyfish, fast simulated annealing is a highly evolved search strategy categorized by a series of predictable movements that bring the jelly closer and closer to large numbers of plankton, its preferred prey. 

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Right whales continue feeding close to Herring Cove Beach

By Mary Ann Bragg

mbragg@capecodonline.com

March 18, 2014

PROVINCETOWN - A half-dozen North Atlantic right whales are in the second day of skimming for food very close to the shore of Herring Cove Beach, a spokeswoman for the Provincetown Center for Coastal Studies said this morning.

The rare whales can be seen from the northern parking lot of the beach, which is in the Cape Cod National Seashore.

Each year the whales come to Cape Cod Bay to feed during the winter and early spring from their summertime breeding and calving grounds along the Atlantic coasts of Georgia and Florida.

There are 510 right whales in the world, according to the North Atlantic Right Whale Consortium, which compiles population estimates from the latest research.

Continued

Blue whales are feeding off New Zealand, not just migrating

Blue whales believed to be foraging in South Taranaki Bight

May 2013. A recent study indicates that Blue whales in a coastal area of New Zealand, known as the South Taranaki Bight, might be doing more than just passing through on their way to and from summer feeding grounds in Antarctica.

Extensive study

A new study, carried out by the National Institute for Water and Atmospheric Research (NIWA), examined opportunistic sightings of Blue whales collected between 1979 and 1999, historical whaling data, stranding events, foraging observations, and sightings recorded during two seismic surveys conducted in 2011.

High density of Blue whales

The findings show that the presence of Blue whales in the South Taranaki Bight is greater than expected and historical whaling data demonstrate a high density of Blue whales in the region throughout time. The study links this increased presence of Blue whales in the Bight to the prominent upwelling system near the South Island's Farewell Spit that generates large clouds of plankton - perfect Blue whale food - in the South Taranaki Bight.

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Bats Use Blood to Reshape Tongue for Feeding

May 6, 2013 — Brown University scientists have found that a species of bat uses blood flow to reshape its tongue while feeding. The quick dynamic action makes the tongue an effective "mop" for nectar and could even inspire new industrial designs. 

(Credit: Cally Harper in the Brainerd-Swartz Lab/Brown University) 

Nectar-feeding bats and busy janitors have at least two things in common: They want to wipe up as much liquid as they can as fast as they can, and they have specific equipment for the job. A study in the Proceedings of the National Academy of Sciences describes the previously undiscovered technology employed by the bat Glossophaga soricina: a tongue tip that uses blood flow to erect scores of little hair-like structures exactly at the right time to slurp up extra nectar from within a flower. 

The bat's "hemodynamic nectar mop," as the paper dubs the tongue tip, features speed and reliability that industrial designers might envy, said lead author Cally Harper, a graduate student in the Department of Ecology and Evolutionary Biology at Brown University. As a matter of what nature can evolve, she said, the tongue tip is surprisingly clever. 

"Typically, hydraulic structures in nature tend to be slow like the tube-feet in starfish," Harper said. "But these bat tongues are extremely rapid because the vascular system that erects the hair-like papillae is embedded within a muscular hydrostat, which is a fancy term for muscular, constant-volume structures like tongues, elephant trunks and squid tentacles." 

In other words, the bat's cylindrical tongue has a mesh of muscle fibers that contract so that the tongue becomes thinner but longer (extending farther into the flower). The discovery reported in the paper is that the same muscle contraction simultaneously squeezes blood into the tiny hair-like papillae. 

Continued: http://www.sciencedaily.com/releases/2013/05/130506181448.htm

Multi-Tasking Whales Sing While Feeding, Not Just Breeding

Dec. 19, 2012 — Humpback whales are famed for their songs, most often heard in breeding season when males are competing to mate with females. In recent years, however, reports of whale songs occurring outside traditional breeding grounds have become more common. A new study may help explain why.

Humpbacks sing for their supper -- or at least, they sing while they hunt for it.

The research, published December 19 in PLoS ONE, uncovers the whales' little-understood acoustic behavior while foraging.

It also reveals a previously unknown behavioral flexibility on their part that allows the endangered marine mammals to balance their need to feed continuously with the competing need to exhibit mating behaviors such as song displays.

"They need to feed. They need to breed. So essentially, they multi-task," said study co-author Ari S. Friedlaender, research scientist at Duke University's Nicholas School of the Environment. "This suggests the widely held behavioral dichotomy of breeding-versus-feeding for this species is too simplistic."

Researchers from the U.S. Naval Postgraduate School, the University of California-Santa Barbara and Duke tracked 10 humpback whales in coastal waters along the Western Antarctic Peninsula in May and June 2010. The peninsula's bays and fjords are important late-season feeding grounds where humpbacks feast on krill each austral autumn before migrating to warm-water calving grounds thousands of miles away.

Read on:  http://www.sciencedaily.com/releases/2012/12/121219174156.htm