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Marine Food Webs Are Collapsing as Ocean Temperatures Rise

Sunday, January 14, 2018 22:57
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A new study has found that levels of commercial fish stocks could be harmed as rising sea temperatures affect their source of food.

University of Adelaide scientists have demonstrated how climate change can drive the collapse of marine “food webs”.

Published in the open access journal PLOS Biology, the study’s lead author PhD student, Hadayet Ullah and supervisors Professor Ivan Nagelkerken and Associate Professor Damien Fordham of the University’s Environment Institute, show that increased temperatures reduce the vital flow of energy from the primary food producers at the bottom (e.g. algae), to intermediate consumers (herbivores), to predators at the top of marine food webs.

Climate change drives collapse in marine food webs
Credit:  University of Adelaide

Such disturbances in energy transfer can potentially lead to a decrease in food availability for top predators, which in turn, can lead to negative impacts for many marine species within these food webs.

“Healthy food webs are important for maintenance of species diversity and provide a source of income and food for millions of people worldwide,” said Mr Ullah. “Therefore, it is important to understand how climate change is altering marine food webs in the near future.”

Twelve large 1,600 litre tanks were constructed to mimic predicted conditions of elevated ocean temperature and acidity caused by increasing human greenhouse gas emissions. The tanks harboured a range of species including algae, shrimp, sponges, snails, and fishes.

The mini-food web was maintained under future climate conditions for six months, during which time the researchers measured the survival, growth, biomass, and productivity of all animals and plants, and used these measurements in a sophisticated food web model.

“Whilst climate change increased the productivity of plants, this was mainly due to an expansion of cyanobacteria (small blue-green algae),” said Mr Ullah. “This increased primary productivity does not support food webs, however, because these cyanobacteria are largely unpalatable and they are not consumed by herbivores.”

Understanding how ecosystems function under the effects of global warming is a challenge in ecological research. Most research on ocean warming involves simplified, short-term experiments based on only one or a few species.

“If we are to adequately forecast the impacts of climate change on ocean food webs and fisheries productivity, we need more complex and realistic approaches, that provide more reliable data for sophisticated food web models,” said project leader Professor Nagelkerken.

Marine ecosystems are already experiencing major impacts from global warming, making it vital to better understand how these results can be extrapolated to ecosystems worldwide.

Image Caption: Reduced energy flow means that the amount of food available for predators – such as fishes – at the top of food webs is reduced, with potential consequences for fisheries species. Image Credit: Lance Anderson, Unsplash. A higher resolution image is available for media.

Contacts and sources:
Professor Ivan Nagelkerken
ARC Future Fellow, Southern Seas Ecology Labs, School of Biological Sciences
Environment Institute
The University of Adelaide


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Total 3 comments
  • Firmament Does Exist

    Don’t consider the effects of Fukishima, cause your a “scientist”?

  • Givys

    What a pack of lies- from the Al Gore hypocrites who want to put in worldwide socialism. These scum already switched from “Global Warming” (remember that one”) to “CLIMATE CHANGE” cause it was apparent that measurements worldwide were showing a cooling trend. Then they scream- this hurricane, this flash flood, this twister, polar bear population, fish die-off, bird numbers diminishing is due to climate change. What horsexxx .

    Fish, people, polar bears are all dying from that Fukushima radiation factory that hasn’t stopped filling oceans & air with pollution. In California, in high radiation areas, fires are mysteriously burning down large areas of housing. Then EPA is quietly “CLEANING” the ground, structures (even concrete) & scrapping 1″ to 1 ft dirt to remove contaminants- of course, unspecified. Then taking contaminated soil to purposely undisclosed place. Where are radiation readings? Gee, uh, we must have lost them. Bet a correlation between populated “HOT ZONES” & suspiciously burned housing; while firemen are told to stand down. COVER UP COVER UP COVER UP COVER UP. Oceans, polar bears, people are dying from early radiation sickness. Some places to “hot” (radioactive) to live in are burnt for the owner’s good. Want to blame someone “FUKUSHIMA” “FUKUSHIMA” & complicit government agencies

  • OzzieEd

    university=studying bullsh%. Hahaha.There’s a lot of dumb people in Australia who still haven’t noticed that our govt is poisoning us with fluoride, Rockerfella fake medicine, toxic vaccines, bullshit science, bullshit news, bullshit courts, bullshit laws, bullshit taxes, etc. etc. Sorry, could have said bulldust but you get my drift. Show me an honest politician and they will be in a body bag soon if not already. I live in southwest Australia and we are having the coldest summer I’ve ever experienced in 59 years. Somehow this fact is not mentioned by the Lamestream propaganda press. Still got 3 blankets on my bed and summers almost over while I’m sitting here in ugg boots and heavy jacket at 5am. The days are very pleasant but none of the swealtering heat we have come to expect. And still, people keep buying into the endless lies about everything from the spin doctors who tell them what to think. Incredible really.

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