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The Kelp coped: ocean gets 5.5 degrees hotter but no effect on giant kelp

After human pumped out 90% of all the CO2 they’ve ever made, the oceans might be a whole fifth of a degree warmer, tops, in the last 60 years. So when water that was a whopping 5.5 degrees warmer rolled over some giant kelp, researchers got excited.  (This is like 1,650 years of climate change right?!)  But the kelp pretty much did nothing, and you might say that researchers were shocked the kelp coped:

Kelp beats the heat

 They expected forests of giant kelp (Macrocystis pyrifera), known to be sensitive to such increases as well as to the resulting low-nutrient conditions, to respond quite rapidly to a rise in water temperature.

However, to the scientists’ surprise, that was not the case. The kelp, they discovered, was all right. Their findings appear in the journal Nature Communications.

“The response that we saw in kelp was really no different than what we’d seen in our temporal record,” explained lead author Daniel Reed, deputy director of UCSB’s Marine Science Institute (MSI). “The values were low but not necessarily lower than what we’d seen during cool-water years.”

A lot of other underwater things were not bothered either:

The team also examined changes in understory algae, invertebrates and fishes of the giant kelp ecosystem and found that they didn’t show much of a response to the warming event either. Sea urchins and sea stars were the exception as they declined dramatically due to a disease that was linked to the warm-water event.

Could it be that natural variations of temperature are normal and have been going on for millions of years. Perhaps kelp has been hit with this sort of rapid shift many times? Have a look at this churning video below. The worlds oceans have streams of warmer water and colder water forming turbulent eddies.

I think this comes from the Scientific Visualization Studio NASA

The global oceans might be warming by 0.2C but marine life lives in water that isn’t average.

BAckground: They have 34 years of data about kelp off California:

The researchers used kelp records from a 34-year time series of data taken by Landsat satellites, which — among many other characteristics — measured kelp canopies. The investigators analyzed kelp biomass from Santa Barbara to San Diego through time and related it to sea surface temperatures at those sites.

The warming was unusual in the 34 year history:

The data showed some large positive temperature anomalies that were unprecedented. For example, in September 2015, the water in the Santa Barbara Channel averaged 4.5 degrees Celsius higher than normal for the entire month. Daily anomalies went as high as 5.5 degrees Celsius. Despite these high temperatures, the team saw no dramatic response by giant kelp whose biomass remained within the range observed during the decades-long time series when the water was cooler.

Naturally if temperatures change by 5 massive degrees, and nothing happens, we need to investigate that:

“Nobody knows how this warming event relates to climate change, other than we’ve not seen this before,” said co-author Libe Washburn, an oceanographer at the MSI and a professor in UCSB’s Department of Geography. “That’s somewhat alarming, but this work may provide some insight into how these kelp forests would respond to future climate warming.”

The money grab:

“The fact that we did not see drastic responses in the rest of the community tells us that we don’t know everything we think we know about this system and about its ecology,” Reed noted. “The results have caused us to pursue lines of research that try to understand how this happens. More importantly, the findings underscore the value of long-term data in terms of trying to tease apart these trends.”


  1. Daniel Reed, Libe Washburn, Andrew Rassweiler, Robert Miller, Tom Bell, Shannon Harrer. (2016) Extreme warming challenges sentinel status of kelp forests as indicators of climate changeNature Communications, vo 7: 13757 DOI: 10.1038/ncomms13757
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