How We Wrecked The Oceans — Part II

The latest issue of Nature contained a paper by Daniel G. Boyce, Marlon R. Lewis & Boris Worm called Global phytoplankton decline over the past century. This research describes a planetary catastrophe which, on a scale of 1 to 10, ranks about 8.5 on the disaster scale. This post should be viewed as a follow-up to How We Wrecked The Oceans (DOTE, May 17, 2010).

Here's the Nature abstract—

In the oceans, ubiquitous microscopic phototrophs (phytoplankton) account for approximately half the production of organic matter on Earth. Analyses of satellite-derived phytoplankton concentration (available since 1979) have suggested decadal-scale fluctuations linked to climate forcing, but the length of this record is insufficient to resolve longer-term trends. Here we combine available ocean transparency measurements and in situ chlorophyll observations to estimate the time dependence of phytoplankton biomass at local, regional and global scales since 1899. We observe declines in eight out of ten ocean regions, and estimate a global rate of decline of ~1% of the global median per year. Our analyses further reveal interannual to decadal phytoplankton fluctuations superimposed on long-term trends. These fluctuations are strongly correlated with basin-scale climate indices, whereas long-term declining trends are related to increasing sea surface temperatures. We conclude that global phytoplankton concentration has declined over the past century; this decline will need to be considered in future studies of marine ecosystems, geochemical cycling, ocean circulation and fisheries.

Phytoplankton are microscopic photosynthesizers, which means that they use light energy from the sun and take in carbon dioxide (CO₂) to produce oxygen. These tiny plants, along with cyanobacteria, do a lot of the work that keeps the biosphere stable. From the press release—

The findings contribute to a growing body of scientific evidence indicating that global warming is altering the fundamentals of marine ecosystems. Says co-author Marlon Lewis, "Climate-driven phytoplankton declines are another important dimension of global change in the oceans, which are already stressed by the effects of fishing and pollution. Better observational tools and scientific understanding are needed to enable accurate forecasts of the future health of the ocean." Explains co-author Boris Worm, "Phytoplankton are a critical part of our planetary life support system. They produce half of the oxygen we breathe, draw down surface CO₂, and ultimately support all of our fisheries. An ocean with less phytoplankton will function differently, and this has to be accounted for in our management efforts."

Doing the math, the researchers estimate that an astonishing 40% of ocean's phytoplankton population has disappeared since 1950! The fewer microscopic plants there are living in the ocean surface waters, the less CO₂ is drawn down from the atmosphere. Thus, the Earth's carbon cycle is being fundamentally altered, with uncertain but surely deleterious effects.

As the press release indicates, the researchers found that warmer surface waters caused by global warming are the main suspect in the decline—

The scientists report that most phytoplankton declines occurred in polar and tropical regions and in the open oceans where most phytoplankton production occurs. Rising sea surface temperatures were negatively correlated with phytoplankton growth over most of the globe, especially close to the equator. Phytoplankton need both sunlight and nutrients to grow; warm oceans are strongly stratified, which limits the amount of nutrients that are delivered from deeper waters to the surface ocean. Rising temperatures may contribute to making the tropical oceans even more stratified, leading to increasing nutrient limitation and phytoplankton declines. The scientists also found that large-scale climate fluctuations, such as the El-Niño Southern Oscillation (ENSO), affect phytoplankton on a year-to-year basis, by changing short-term oceanographic conditions.

In other words, warmer oceans are not well mixed at the surface, with warmer water sitting atop colder deeper water. Photosynthesizers must live in the surface waters where there is access to sunlight, but do not get the nutrients from upwelling colder water required by their metabolism. So they die off.

It is clear that we have a disastrous positive feedback loop at work here, in which warmer surface water supports fewer phytoplankton, which then take up less CO₂ from the atmosphere, which causes the surface water to warm some more due to the greenhouse effect, etc. In fact, one of the crazier geo-engineering solutions to global warming is to seed the ocean surface waters with iron filings to stimulate phytoplankton growth!

Up to this point, I have written up this disaster without much emotion. That's probably because it's so depressing. If this trend continues, we Earthlings are surely fucked. And maybe on relatively short time scales (a few decades). In fact, if we have indeed lost 40%  of the phytoplankton in the oceans since 1950, I do not understand why we have not felt the terrible effects already. Perhaps the Earth's biosphere (primary productivity) and nutrient recycling (as with carbon) are more resilient than they appear. None of this is well understood, but our uncertainty cuts both ways.

I think there's a certain point—perhaps we have just now passed it—where all you can do is throw your hands up in the air and shout out what the fuck do we do now? Frankly, I hope this phytoplankton decline result is wrong, but I fear it is right.

Related Posts

How We Wrecked The Oceans
Peak Fish And The Biodiversity Crisis

Comments

[Edward Boyle]

Eat, Drink and be merry...

[ExtraO]

@Edward Boyle
You got that right.

Yeah, We Earthlings are surely f.u.c.k.e.d. Mostly I think it may be the next two or three generations after Dave's that are the most fucked, but time will tell. The trend doesn't really need to continue for this to be true. Wondering why we haven't felt the effects of the missing 40% of our oxygen producers? Well that 40% hasn't been missing since 1950, it's been gradually building up to that rate over the last 60 years. Rest assured we'll feel it soon enough. It takes about 30-40 years before the effects of carbon emissions are "felt", there's probably some slop like that in the oxygen depletion rate too. Someday oxygen starvation may be apparent at 6,000 feet instead of 14,000.

[Richard Warren]

How long until we begin seeing a decrease in oxygen levels in the atmosphere? What level must the oxygen producers have for long term oxygen levels in the atmosphere to remain stable?

[ShaktivaIrahs]

Last year an geo-engineering experiment by adding iron into the sea caused a major growth in algae. Probably at that scale dismissable.

I think nature does find a way, every time major upheaval happened, nature has found a way: some died, others thrived. It's a dynamic that kept things going.

It's also here where I worry: with all the human need for control, we are losing the dynamics, we lost our adaptation and every living thing under it's control. Think domesticated dogs, plants, dams, all depending on our interference, our control.

It is backfiring because history proved that being under total control of a freak dictator is asking for a rebellion.
Backfiring because we can't be always that attentive and precise. Backfiring because whatever progress we think we made, we still can't cure a cold...we don't know everything to take care of the things we decided to control.
Humans are now the freak dictator with no respect for boundaries, balance/justice and temperance.

The best we can do for our world is stop to control it, keep it small, simple and close by and become good stewards along the way rather than dominators and dominatrices.

[Mike O'Brien]

Hi, Dave--

A place to start is by clarifying our thinking. Since we think in English that means using appropriate words to describe what we are trying to communicate. That's especially important in an emotional context where the wrong words can make a bad situation worse. Bad situations, like the phytoplankton drop, demand clear thinking.

When you say "we're fucked" to me that makes me happy because I enjoy nothing better than a good fuck with my partner. It's confusing that you use it as a negative meaning "we're ruined".

Using a word like fucked, a code word for anger, is a displacement that avoids or masks the actual cause of distress, just as anger is a mask for fear. Anger feels righteous and spares us from directly facing our fears. I encourage you to find a more accurate way to express your deep emotions, because then we can take the next step of responding to them.

Lest you think I'm joking, I believe the collapse of the phytoplankton is directly linked to human denial, expressed in the language of lies, coverup, avoidance and distortion, that allows us to justify our destruction of the planet.

[DarkOptimism]

@Edward Boyle
Gah, that being the response to, well, everything is what got us here in the first place.

[Adam Schuetzler]

I find this to be somewhat unlikely - it seems very strange to me that we could lose 40% of phytoplankton without there being disastrous effects fairly soon in terms of oxygen, sea life, etc. Conditionally, I'm calling this one sketchy and assuming something is not well understood here.

That's not to say I don't think we've hashed it; just to say that I'm not sure we would be alive right now if we'd hashed it that bad.

One thing I am certain of is that the Earth and life will outlast humans. There are a lot of things on this planet much more resilient than us naked apes. That's not much comfort, but I think it must be kept in mind when thinking about ecological disaster. Ultimately, we have to think in terms of our survival being dependent on maintaining an earth much like what has existed for the past 10,000 years. Sadly we're still stuck in the extraction mentality for the most part.

[b-mused]

The problem with complex adaptive systems is we don't understand the tipping points. Has there been a 40% drop? Maybe. At what point does it get critical, i.e., are we drawing down a savings pot, what are the critical interactions.
The worrying thing would then be a rapid non-linear change in the system.
Just speculating but maybe the decline is not showing up ecosystems dependent on this food source such as fisheries because their so badly depleted.
Some studies suggest that oceans ability to absorb CO2 is decreasing.

[terry mcneely]

i heard this report and appropriately alarmed. So i got to wondering if the oxygen content has decreased in the last decades, and it has, but not much, about 1/2 of 1/10th of 1percent, as measured by the Keeling curves, onefor oxygen, the other measures CO2 concentrations. The more immediate effect may be on ocean food systems. But that is just a guess. But we as humans are causing effects on these complex systems we are all part of.