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Alarmist Phytoplankton Decline Exposed as Sampling Bias: Rising CO2 intensifies blooms

Written by Myles, PSI Researcher & John O'Sullivan

Climate scientists have alleged Phytoplankton decline had hit an astonishing 40 percent. Media hype was built up around the claims of researcher, Daniel Boyce and friends who released a paper seemingly proving a decline over a century long measurement set of chlorophyll levels in the oceans. The paper appeared in Nature. Yet in the very same edition of the journal another study had made contradictory claims. So guess which story the mainstream media ran with?phytoplankton

Boyce’s sensational scientific claims took centre stage – it supported the monotnous global warming narrative still popular in mainstream media.

More or less chlorophyll serves as an indicator of the amount of photosynthesis from phytoplankton that is occurring in bodies of water. In samples chlorophyll being produced during photosynthesis. The alarmist authors assert their findings help prove “global warming.”

The paper titled “Global phytoplankton decline over the past century” is being further contradicted as evidence mounts that it is a hyped scientific scare story from Boyce which runs counter to oceanographic scientific consensus. So let’s look at the facts:

The researchers state…

  These fluctuations are strongly correlated with basin-scale climate indices, whereas long-term declining trends are related to increasing sea surface temperatures.” (Nature; Volume 466)

Contrary Peer-reviewed Study Indicates Sampling Bias

Meanwhile, in another research paper in Nature (Volume 472) titled “A measured look at ocean chlorophyll trends” the authors find that the alleged one percent a year decline alleged by Boyce in phytoplankton biomass over four decades has not occurred. Authors dispute Boyce’s key finding stating that:

Our results indicate that much, if not all, of the century-long decline reported by Boyce et al.1 is attributable to this temporal sampling bias and not to a global decrease in phytoplankton biomass.”

In a startling reversal another paper in the same edition of Nature cited above, titled ‘Is there a decline in marine phytoplankton?‘ the authors state the opposite of Boyce – that there can be shown to be an increase in phytoplankton biomass, stating:

“Eight decades of data on phytoplankton biomass collected in the North Atlantic by the Continuous Plankton Recorder (CPR) survey2, however, show an increase in an index of chlorophyll (Phytoplankton Colour Index) in both the Northeast and Northwest Atlantic basins34567 (Fig. 1), and other long-term time series, including the Hawaii Ocean Time-series (HOT)8, the Bermuda Atlantic Time Series (BATS)8 and the California Cooperative Oceanic Fisheries Investigations (CalCOFI)9 also indicate increased phytoplankton biomass over the last 20–50 years. 

Also, evidence from the Royal Society, England, shows increases in Phytoplankton are related to warm sea surface temperature:

However, phytoplankton biomass also responds strongly to climatic variability at shorter time scales. Heatwaves, nutrient run-off from storms, upwelling events or drought-induced increases of water residence time can all trigger algal blooms. Massive blooms of cyanobacteria and dinoflagellates (red tides) are often responses to anomalous warm temperatures and stable stratification (Huisman et al. 2004Hall et al. 2008Jöhnk et al. 2008). Extreme nutrient run-off produced by tropical storms triggered dinoflagellate blooms in the Neuse River estuary (Hallet al. 2008) and increased Chl-a in Florida Bay (Briceño & Boyer 2010). In the Black Sea warm temperature and low wind stress can trigger unusually large blooms throughout the entire growing period (McQuatters-Gollop et al. 2008). Similarly, increased wind stress, water temperature and reduced water run-off affected the phytoplankton dynamics in Boreal lakes (Schindler et al. 1990).

Increased Atmospheric CO2 also Enhances Phytoplankton Biomass

Clearly there is scientific dispute. Evidence shows warm temperatures cause elevated numbers of phytoplankton – not a decline. Also the increased atmospheric CO2 levels stimulate phytoplankton growth in lakes and the same must be true for the oceans as per the paper, Rising CO2 levels will intensify phytoplankton blooms in eutrophic and hypertrophic lakes.’  This paper tells us:

Harmful algal blooms threaten the water quality of many eutrophic and hypertrophic lakes and cause severe ecological and economic damage worldwide. Dense blooms often deplete the dissolved CO2 concentration and raise pH. Yet, quantitative prediction of the feedbacks between phytoplankton growth, CO2 drawdown and the inorganic carbon chemistry of aquatic ecosystems has received surprisingly little attention. Here, we develop a mathematical model to predict dynamic changes in dissolved inorganic carbon (DIC), pH and alkalinity during phytoplankton bloom development. We tested the model in chemostat experiments with the freshwater cyanobacterium Microcystis aeruginosa at different CO2 levels. The experiments showed that dense blooms sequestered large amounts of atmospheric CO2, not only by their own biomass production but also by inducing a high pH and alkalinity that enhanced the capacity for DIC storage in the system. We used the model to explore how phytoplankton blooms of eutrophic waters will respond to rising CO2 levels. The model predicts that (1) dense phytoplankton blooms in low- and moderately alkaline waters can deplete the dissolved CO2 concentration to limiting levels and raise the pH over a relatively wide range of atmospheric CO2 conditions, (2) rising atmospheric CO2 levels will enhance phytoplankton blooms in low- and moderately alkaline waters with high nutrient loads, and (3) above some threshold, rising atmospheric CO2 will alleviate phytoplankton blooms from carbon limitation, resulting in less intense CO2 depletion and a lesser increase in pH. Sensitivity analysis indicated that the model predictions were qualitatively robust. Quantitatively, the predictions were sensitive to variation in lake depth, DIC input and CO2 gas transfer across the air-water interface, but relatively robust to variation in the carbon uptake mechanisms of phytoplankton. In total, these findings warn that rising CO2 levels may result in a marked intensification of phytoplankton blooms in eutrophic and hypertrophic waters.

Eutrophication Raises Phytoplankton Biomass

Additionally, there are still more factors that increase phytoplankton numbers. One being that increased levels of fertilizer in water runoff from farming also increases their nutrients supply and boosts biomass.

This increased nutrient loading of predominantly nitrogen and phosphorous from river runoff is a worldwide phenomenon resulting in there being too many phytoplankton in numerous locations around the world. This process known as “eutrophication” has resulted in a substantial increase in phytoplankton blooms around the world.

A team of researchers from Stanford University have proven that there is link with fertilizers and a common result of eutrophication is:

  • Increasing biomass of phytoplankton resulting in ‘algal blooms’.

It is illustrated here that the slight warming up till the turn of the century (from whatever source) increased levels of CO2 and increased eutrophication all lead to increased phytoplankton biomass.

Yet alarmist climate science managed to find a century-long decline which has been exposed to be little more than a measurement bias. There is also clear evidence of media bias in favour of alleged phytoplankton decline with a distinct lack of space offered to opposing research in the matter

So is phytoplankton biomass really in decline or can we once again dismiss such an environmental scare story as a coordinated promotion by alarmist ‘scientists’ in tandem with a sensation-hungry media?


Comments (2)

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    Pffffttt, I knew that research to be bunk from the very get-go … I own a pool … anyone that owns a pool knows that algie LOVE warmer water … enough said … case closed

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    Al Shelton


    The Alarmist writers of so-called “scientific papers” are just a bunch of paid shills, trying to keep the CAGW scare going up until the next election 2016.
    It is all a pack of lies and biased speculations. IMO

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