# Would a volcanic winter trigger an oceanic “spring”?

There is large amounts of observations supporting the effects of volcanic eruptions on climate: A long term subtle warming effect due to $$\small\mathsf{CO_2}$$ and a short term, but more intense cooling effect due ash and sulfur gases. There is also much evidence supporting long and dramatic volcano triggered cooling events dubbed "volcanic winters", like the one after the 1815 eruption of Mount Tambora, or the Toba catastrophe 74,000 years ago, perhaps lasting up to a decade.

For more recent volcanic eruptions, there is evidence of algae blooms produced by the input of nutrients from volcanic eruptions (1, 2). Perhaps an expected outcome given that the ecosystems at the surface of the ocean are nutrient limited, therefore wasting most of the available energy due to the lack of iron, nitrogen and phosphorous mainly.

For all the above, I would be inclined to think that a large volcanic winter would encompass a period of prosperity for oceanic life. Where a small decrease in solar irradiation is more than compensated by a large increase in nutrients availability. However, I haven't hear of evidence of such oceanic boom.

Are there observations suggesting or disproving such oceanic booms during volcanic winter events?

PS: I started pondering this question while thinking about this article, on which they found that a coastal community in South Africa didn't seem to have been affected by the Toba "catastrophe", but on the contrary, they seem to have benefited from it.

• By volcanic winter, you mean when a volcano is dormant? – Eevee Mar 22 '18 at 22:14
• Nop, I mean a global drop of temperature due to volcanic activity. You can visit the corresponding wikipedia article to learn more: en.wikipedia.org/wiki/Volcanic_winter – Camilo Rada Mar 22 '18 at 22:20
• biogeosciences.net/10/3715/2013/bg-10-3715-2013.pdf – trond hansen Apr 7 '19 at 5:47
• @CamiloRada i am not qualified to answer this question but you are and there is nothing wrong with answering your own question.all the information do show volcanoes can have a positive effect on life in the ocean,like this study researchgate.net/publication/… – trond hansen Apr 10 '19 at 6:04
• my point is if the nutrients is there then life will grow,when spring comes volcanic or not. – trond hansen Apr 10 '19 at 6:20

I can't answer the question in detail but maybe take some of the tension, addressing the so called bottleneck hypothesis.

It was never really supported by archaeology, the mentioned article just adds to the evidence that human variety didn't suffer that greatly from the Toba eruption as the bottleneck hypothesis might suggest and that there was no decade long volcanic winter.

Example from lake Malawi after the eruption: https://www.sciencedirect.com/science/article/abs/pii/S0047248417302750?via%3Dihub

Southe Africa: https://www.nature.com/articles/nature25967

And to my knowledge no extinction signal in Neandertal population (they were few anyway) during oxygen isotope stage 4 in Europe.

Some think that it is time to put the bottleneck hypothesis ad acta.

There is evidence that eruptions "fuel" phytoplankton, but not necessarily connected to volcanic winters.

The Deccan Traps super-eruption 66 million years ago dwarfed even the Toba eruption of 75 thousand years ago and, perhaps assisted by the Chicxulub impact, had a very damaging effect on marine life, where extinctions were just as high as on land. I doubt whether the beneficial aspects of a really large eruption, such as adding vital nutrients to the surface waters of the ocean, would outweigh the deleterious effects such as global cooling. There are a few super-volcanoes around the world waiting to erupt, one of them in Yellowstone National Park, but none are expected to erupt in the next few thousand years, and when Yellowstone does eventually blow it is highly unlikely to be as severe as the Deccan Traps eruptions and probably not as bad as Toba.

• Interesting! Do you have any reference to material/papers showing that the Deccan traps emplacement was followed/associated to a marine life extinction event? – Camilo Rada Jul 9 '19 at 19:41
• There are three schools of thought: 1) The Deccan Traps did it all. 2) Chicxulub did it all 3) It was a combined effort/ – Michael Walsby Jul 9 '19 at 21:47
• @CamiloRada feels to me like the huge amounts of carbon dioxide emitted during the traps would end up mostly in the ocean, killing stuff – Gimelist Jul 20 '19 at 1:09
• @Michael Walsby it is not that simple. A stressed out environment can't be attributed to single events, these may be just the last straw or cause local extinctions that leave an artifact in todays research. – user18411 Dec 17 '19 at 8:31
• It is my understanding that the 3 main gases releases to change atmospheric content were methane, CO2 and SO2. eurekalert.org/pub_releases/2019-02/aaft-tse021919.php Based on avg. temperature change, it would appear SO2 was largely the culprit for temperature change, NOT CO2? – J. Kaciulis Dec 17 '19 at 16:18