Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search

 

Scientists listen to the sound of photosynthesising seaweeds

NIWA scientists are hoping they may one day be able to “listen” to kelp forests in the waters around New Zealand to find out how they are faring.

Dr Giacomo Giorli, a NIWA marine acoustician, is one of the authors of a recently published scientific paper that identified the sound generated as a by-product of photosynthesis in marine macroalgae or seaweed.

The study showed how gas bubbles released by seaweeds during photosynthesis produce sounds which correlate to the amount of oxygen released.

“Declining algal cover is one of the major indicators of stress in coral reef ecosystems. Our observation suggests that monitoring the sounds generated by the algal photosynthesis could be potentially used to estimate the amount of algal cover and ecosystem health in coral reefs. “

Dr Giorli’s and his colleagues’ research at The Hawaii Institute of Marine Biology involved collecting a large amount of the algae Gracilaria salicornia and placing it in an experimental tank equipped with an aquarium light.
The algae were exposed to cycles of dark and light and a hydrophone was used to measure the sound in the tank while a high-resolution video camera recorded the bubbles and measured their size.

“Bubbles form on the algal tissue when oxygen is produced by the alga. The bubbles grow with the addition of more oxygen and then float towards the water surface,“ Dr Giorli said.

The sound comes from the tiny movements of the bubbles as they form a spherical shape in the water.

“During release, relaxation of the bubble to a spherical shape creates a sound source that ‘rings’,” the scientists found. “The bigger the bubble, the lower the sound. The whole process was reversed when we turned the light off.”
While measuring the sound produced by the bubbles could be used as a cheap alternative to estimate algal cover and ecosystem health in coral reefs, NIWA scientists say there is also potential to use it to learn more about New Zealand kelp forests.

NIWA marine biologist Dr Roberta D’Archino says the kelp forests are in decline overseas but little baseline data exist about the size and distribution of these forests in New Zealand.

“Some kelp species are very sensitive to increasing temperatures – we know for instance that the giant kelp Macrocystis pyrifera has decreased up to 90% in Tasmania, and that the range of kelps in Western Australia retracted more than 100km after an extreme heat event. However, while there is some monitoring going on in New Zealand, we don’t really know much about how they are being affected on a large scale.

“Kelp provide important habitats for fish, rock lobsters, paua and other species. We have been exploring different ways to map the forests, and if we could work out a way to link oxygen production to the kelp biomass it would be very exciting.”

The paper was written by Dr Giorli together with Simon and Lauren Freeman from the US Naval Undersea Warfare Center, and Andreas F. Haas from the Royal Netherlands Institute for Sea Research.

© Scoop Media

 
 
 
Business Headlines | Sci-Tech Headlines

 

Stats NZ: Election Boosts October Job Numbers

Job numbers were boosted by general election staff in October 2020, along with rises in the manufacturing, retail, and hospitality industries, Stats NZ said today. Filled jobs rose by 27,667 to 2.2 million in October 2020 compared with September, after ... More>>

Government: New Year Border Exception For Seasonal Workers In The Horticulture And Wine Industries

2000 additional RSE workers to enter New Zealand early next year employers must pay these workers at least $22.10 an hour employers will cover costs of managed isolation for the RSE workers RSE workers will be paid the equivalent of 30 hours work a week ... More>>

ALSO:

Grey Power: Is Disappointed To Learn Of More Bank Closures

Many older people are being left without essential services because of cost cutting and the march of modern technology. It is now expected that most banking transactions can occur via the internet or telephone. Jan Pentecost, President of the Grey Power ... More>>

ALSO:


Department Of Conservation: Big Year Underway At Albatross Colony

Familiar faces are returning for the new season of Royal Cam, with a big breeding year underway for the toroa/northern royal albatross colony on Otago’s windswept Pukekura/Taiaroa Head. More than 120 albatrosses, a taonga species, have returned ... More>>

Real Estate: ASB Survey Reveals Majority Of Kiwis Expect House Prices To Keep Climbing

ALSO:

House price expectations are soaring as New Zealand’s housing market shifts up a gear. But stretched affordability is putting a dent in perceptions of whether it’s a good time to buy. While Kiwis reveal they do expect interest rates to fall further. ... More>>

ComCom: How Real Is That Bargain?

The Commerce Commission urges retailers and consumers to think hard about the bargains being offered as ‘Black Friday’ and Christmas draw near. Black Friday has now overtaken Boxing Day in terms of retail spending, according to data from electronic ... More>>

Stats NZ: Births And Deaths: Year Ended September 2020

Births and deaths releases provide statistics on the number of births and deaths registered in New Zealand, and selected fertility and mortality rates. Key facts For the year ended September 2020: 57,753 live births and 32,670 deaths ... More>>

ALSO: