Scientists discover link between climate change and biological evolution of phytoplankton

International team’s findings follow the astronomical pacing of Earth’s orbit
Peer-Reviewed Publication

New Brunswick, N.J. (Dec. 1, 2021) – Using artificial intelligence techniques, an international team that included Rutgers-New Brunswick researchers have traced the evolution of coccolithophores, an ocean-dwelling phytoplankton group, over 2.8 million years.

Their findings, published this week in the journal Nature, reveal new evidence that evolutionary cycles in a marine phytoplankton group are related to changes in tropical seasonality, shedding light on the link between biological evolution and climate change.

Coccolithophores are abundant single-celled organisms that surround themselves with microscopic plates made of calcium carbonate, called coccoliths. Due to their photosynthetic activity, mineral production and widespread abundance throughout the world’s oceans, coccolithophores play an important role in the carbon cycle.

Scientists have long thought that climate changes’ effects on plants, animals and other organisms occur in cycles, which are reversed when each cycle is completed, thus erasing any small evolutionary changes during each cycle. In contrast, evolutionary changes, as known from the fossil record, are non-cyclic trends that occur over millions of years.

But the researchers’ new study shows that evolutionary cycles in coccolithophores are attributed to changes in tropical seasonality related to shifts in the Earth’s orbit that occur about every 400,000 years. The study may also offer a new understanding of the approximately 400,000 year-long variations in records of the oceans’ carbon cycle.

“The production of calcium carbonate by these prolific coccolithophore species likely impacted the chemistry of seawater and the oceanic carbon cycle, which in turn could have significant consequences for Earth’s climate through the ocean influence on the concentration of atmospheric carbon dioxide,” said the study’s co-author Yair Rosenthal, a Distinguished professor at Rutgers.

The researchers used AI techniques to study the shape of nearly nine million coccoliths from more than 8,000 samples, each representing a point in geological time or space, tracing coccolithophore evolution over 2.8 million years. The samples came from tropical sediment cores from the ocean floor recovered during scientific drilling expeditions.

Automated optical microscopes captured the images, from which species are recognized and their size and weight measured. These size and weight records revealed the presence of cycles lasting 100,000 years and 400,000 years, which correspond to variations in the shape of the rotation of the Earth around the sun, known as the eccentricity of the Earth’s orbit. Unexpectedly, these cycles are not the same length as those followed by global climate cycles and glaciations over the last 2.8 million years.

“The eccentricity cycles have multiple effects on the earth,” said Luc Beaufort, a lead author of the study. “One of the little-known effects is the periodic appearance of seasons at the equator. At the present time, when Earth follows an almost circular orbit, the equator experiences a very weak change in seasons, but when the orbit is eccentric and shaped more like an ellipse than a circle, seasonal changes in tropical regions become stronger.”

This effect on tropical seasonality is different than the cause of seasonality at higher latitudes, which is driven primarily by the inclination of the earth’s axis of rotation.

“We modelled the effects of changing seasonality driven by eccentricity in the tropical ocean, demonstrating that the effects on marine ecosystems are significant and could explain the adaptation of coccolithophores to new niches created by these cyclical seasonal conditions,” said Clara Bolton, a co-author of the study.

The study included researchers from Rutgers-New Brunswick in the USA and the Centre for Research and Teaching in Environmental Geoscience (CEREGE) in France.

Rutgers University–New Brunswick is where Rutgers, the State University of New Jersey, began more than 250 years ago. Ranked among the world’s top 60 universities, Rutgers’s flagship is a leading public research institution and a member of the prestigious Association of American Universities. It has an internationally acclaimed faculty, 12 degree-granting schools and the Big Ten Conference’s most diverse student body.



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Sampling sites for eukaryotic phytoplankton metatranscriptomes and sequence distribution. a, Sampling sites and surface ocean temperatures. Two stations each were sampled for EPAC and ANT. b, Sequence-distribution Venn diagram for pooled sequence clustering based on CD-HIT (longest open reading frames clustered using 60% similarity and 50% overlap of sequences). U is all sequences under consideration, numbers show sequences that fall into clusters from the environment(s) represented by that section of the Venn diagram. Percentages show the proportion of sequences that are specific to a particular environment. Part a is reproduced with permission from the World Ocean Atlas 2009 ( temperature/JPEG/t_0_0_1.jpg), © National Oceanic and Atmospheric Administration/Department of Commerce.

Increasing cellular concentrations of ribosomal proteins partially compensate for the reduced translation efficiency under low temperatures, which has implications for how fast cells are able to progress through the cell cycle and, hence, their ability to build up biomass.


The Earth's fluctuating orbit around jolly old Mr. Sun could actually impact biological evolution.

The French National Centre for Scientific Research (CNRS), has found clues that orbital eccentricity is driving evolutionary bursts of new species, at least in the photosynthesizing plankton (phytoplankton).

Coccolithophores are microscopic sunlight-eating algae that create plates of limestone around their soft, single-cellular bodies. These limestone shells, called coccoliths, are extremely prevalent in our fossil records – first appearing around 215 million years ago during the Upper Triassic.

These phytoplankton are responsible for the massive White Cliffs of Dover made famous in the story, 'David Copperfield' where his aunt Betsy Trotwood took care of him with Mr. Dick in their home atop those cliffs; and the song, 'There'll Be Blue Birds Over the White Cliffs of Dover' by Dame Vera Lynn.

See: David Copperfield by Charles Dickens, Vintage Classics, ©January, 2012 (available at Amazon)


Even the smallest animals, the coccolithophores, now offer us ideas on the impacts associated with the Earth's tropical seasonality related to shifts in the Earth’s orbit which occur about every 400,000 years. The overall response of the marine ecosystem to climate change includes both the ‘direct’ effects of temperature on marine physiology and the ‘indirect’ effects on the same physiology due to ocean stratification changes.
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Feb 27, 2022
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I know this is an old one but I got a statement and a question.

Calcite can't turn carbonate without excess CO2 present in the water.
At the top with the insert dotted orbit, the Earth changes gravitational pull all the time in a year before repeating it again, was that considered a factor or is it just light/radiation strength ?
Mr Oddball -

First of all, microscopic coccolithophores, coral-building algae, and giant snails engineer their own building material by pulling two dissolved chemicals, calcium and carbonate, out of the water to form solid shells of calcium carbonate. The reason those shells don't dissolve back into calcium and carbonate as soon as they're built is that ocean water is already holding as much calcium and carbonate as it can, so the mineral forms much more easily than it dissolves.

At greater depths, the water isn't quite as saturated with calcium and carbonate, and thus calcium carbonate is easier to dissolve. So unlike shallow coastal waters where shells of dead creatures build up on the sea floor, out in the deep ocean there's a depth at which calcium carbonate starts to break apart and empty shells dissolve before reaching the bottom.

This dissolving depth depends on the concentration of calcium and carbonate already in seawater. If the concentration is high, shells sink deeper before their calcium carbonate dissolves. And if the concentration is low, the dissolving depth moves closer to the surface, meaning the deepest intact shells begin to dissolve.

But this is a feedback loop. Shells that dissolve add more calcium carbonate to the water, making it harder for other shells to dissolve and lowering the dissolving depth. Basically, chemistry in the deep ocean stabilizes the concentrations of calcium and carbonate in the seawater, which is why the upper part of the ocean is saturated with calcium carbonate and perfect for shell-building to begin with.

We must take into account the chemistry of another key part of the ocean-- the atmosphere. At the ocean's surface, a small proportion of gases like oxygen and carbon dioxide dissolve into the water. Dissolved oxygen, for example, allows sea creatures to breathe. And when the concentration of the gases in the atmosphere rises or falls, so does the amount of gas dissolved in the oceans.

If it weren't for the ocean's own balancing act, any incoming carbon dioxide would be bad news for shell-builders because more CO2 means less CO3. Dissolved CO2 molecules combine with water to form what's called carbonic acid, which in turn combines with carbonate to form hydrogen carbonate. When carbon dioxide in the atmosphere increases, carbonate in the ocean decreases and shell-building gets harder to do, at least for a moment. Given enough time, the physics and chemistry of the ocean will cause the dissolving depth to rise, and more shells on the sea floor will return their calcium and carbonate back to the water, restoring normal levels.



You mention "the Earth changes gravitational pull all the time in a year", which I am unfamiliar with.

However, you may be referring to the one important rotating frame is the surface of the Earth, rotating with a period of about 24 hours--more accurately, 23 hrs 56.07 min or 86164 seconds. If the equatorial radius of Earth is 6378 kilometers, the circumference comes to 40074 kilometers--slightly more than the 40,000 kilometers supposed to be the pole-to-pole circumference, implied by the definition of "one meter." The difference comes because the Earth bulges out at its equator. The velocity of the equator then is
40074 / 86164 = 0.4651 km/sec = 465.1 meter/sec.

That velocity is directed eastwards and is significantly faster than the speed of sound, which is about 335 m/s. Space rockets from Cape Canaveral need to attain about 8 km/s (in the frame of reference of the non-rotating center of the Earth ) to achieve orbit, so to give them a favorable starting velocity, such rockets are generally launched eastwards.

To derive the centrifugal acceleration on the equator (i.e. the force in Newtons on one gram mass, rotating with the Earth), we calculate in meters and seconds
v2 / r = (465.1)2 / 6378000 = 216318 / 6378000 = 0,03392 m/s2.

Comparing this to the acceleration of gravity--say 9.81 m/s2--it is only 0.00346 or 0.346%. Effective gravity on the equator is reduced by the rotation, but only by about 1/3 of a percent

Assuming the Earth is exactly spherical, we expect gravity to always point towards the center of Earth. However, the centrifugal force is perpendicular to the axis of the Earth. Except on the equator, therefore, it is not exactly opposed to gravity, but adds a small horizontal vector component, pointing towards the equator (dashed arrow in the figure). As a result, not only is effective gravity weakened, but its direction is modified--instead of pointing to the center of the Earth, is slants (ever so slightly) towards the equator.

Does this mean that if you placed a perfect ball on a very smooth horizontal surface, gravity would make it roll equatorward? Suppose it was so. That same force would also act on the water of the ocean and make it also flow equatorwards, and even the solid Earth might deform!

How long would this go on? Well, until the equatorial pile-up of material forms a "hill" around the Earth, rising slightly towards the equator, where its top would be. No more flow towards the equator would occur once the slope of the ground, as modified by the hill, would be exactly perpendicular to the effective direction of (modified) gravity. With such a slope, a perfect ball placed on a perfectly horizontal surface would no longer try to roll anywhere, and forces on oceans and on land would no longer try to move matter horizontally.

By now you should realize what this gives us--an explanation to the equatorial bulge of the Earth! That bulge is nothing but the "hill" described above, and the shape of the surface is such that the ground is always perpendicular to the effective gravity.

Their result was later disproved by more accurate observations, but even before that, Newton by the following simple argument showed this could not be so. Assume Earth is a sphere, and imagine two deep holes extending to its center (see drawing), meeting there and filled with water. If Earth did not rotate, one may have expected the height of each water column to be the same: at the center of the Earth, by symmetry, each column would push down with the same weight, creating an equilibrium.

On a rotating Earth, however, the centrifugal force acts to reduce the weight of the water in the equatorial hole, and the water would rise there to greater height. Newton then argued that water anywhere would rise to the same level...if our earth were not a little higher around the equator than at the poles, the seas would subside at the poles and, by ascending in the region of the equator, would flood everything there.

Everyone on Earth, live in a rotating frame of reference. Should we therefore refrain from using Newton's equations in everyday life? It turns out that for motions on a scale much smaller than the size of Earth, at moderate velocities, the effects are negligible.

One example concerns the famous question of whether draining water in kitchen sinks on opposite sides of the equator swirls in opposite directions, as is sometimes claimed. It turns out (see next section) that the effect in principle exists, but is much too small to affect observations.

In the world wars, gunners firing large cannons corrected their aim (slightly) to account for the Earth's rotation, but you and I can usually ignore it, except for the modification of gravity by the centrifugal force.


In closing, I believe that your last question on radiation as a factor in the calcium and carbonate in seawater is answered above when seen that the dissolving depth of the minerals is variable and that the processes involved are not light sensitive.
Feb 27, 2022
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I can understand better now why Calcium carbonate get's an exception with solubility in seawater.
My question was about elliptical orbits increased and decreased.
Like now the solid orbit line would be ideal for these little guys to effect climactic changes because temperature and lumens allow for it, but an increased elliptical orbit like the dotted line orbit would put heat, lumens and gravity in charge of climatic changes not just triggering it.

So , Can the the differing in layering of plates be a defense depending on something, or an evolution because of something ? The somethings being gravity, lumens and heat due to location in the orbits.

I hope that makes sense.
Feb 27, 2022
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I was thinking layering plate is a good defense against weight (armor), and lattice at good defense against heat, and color a good defense against lumens.
Things Mr. Sun will impose.
OddBall, here is some interesting information for you, which may serve to more fully answer your questions and which, I believe, directly apply to your comments:

Over the last 20 years a lot of research has been carried out on the process of coccolith formation, with some species producing one coccolith at a time (e.g., E. huxleyi), while others produce both organic scales and coccoliths in a continuous production line (e.g., Pleurochrysis carterae). In general, heterococcoliths are formed in specialized vesicles (coccolith vesicles) originating from the Golgi body. Within these vesicles, calcite crystals are initially laid down on an organic base plate (the base plate scale), and after the coccolith is completed, it is usually excytosed through the flagellar area, and then rhythmically incorporated into the coccosphere. Holococcoliths, on the other hand, are formed extracellularly in the space between the plasmalemma and the outer ‘skin’. This apparent lack of cell control during holococcolith formation may be the reason why holococcoliths are composed of undifferentiated rhombohedric crystals. However, despite this, holococcolith morphology is extremely diverse and exceedingly intricate.

Calcification has high energy demands and coccolithophores might have calcified initially to reduce the grazing pressure from other phytoplankton, but that additional benefits such as protection from photo damage and viral/bacterial attack further explain their high diversity and broad spectrum ecology.

The cost-benefit aspect of these traits is illustrated by novel ecosystem modeling, although conclusive observations remain limited. In the future ocean, the trade-off between changing ecological and physiological costs of calcification and their benefits will ultimately decide how this important group is affected by ocean acidification and global warming.

coccolithophore diversity.jpeg
Diversity of coccolithophores.
Emiliania huxleyi, the reference species for coccolithophore studies, is contrasted with a range of other species spanning the biodiversity of modern coccolithophores. All images are scanning electron micrographs of cells collected by seawater filtration from the open ocean. (A to N) Species illustrated: (A) Coccolithus pelagicus, (B) Calcidiscus leptoporus, (C) Braarudosphaera bigelowii, (D) Gephyrocapsa oceanica, (E) E. huxleyi, (F) Discosphaera tubifera, (G) Rhabdosphaera clavigera, (H) Calciosolenia murrayi, (I) Umbellosphaera irregularis, (J) Gladiolithus flabellatus, (K and L) Florisphaera profunda, (M) Syracosphaera pulchra, and (N) Helicosphaera carteri. Scale bar, 5 μm.

Calcification might serve to protect the cell from photodamage (deterioration of photosynthetic performance due to damage from excess irradiance) for coccolithophore species living in the upper ocean. It might do so either by providing a sunshade or as an energy dissipation mechanism under high-light conditions. Phytoplankton in general experience fluctuating light levels as they passively circulate through the depth of the mixed layer, facing a light difference of perhaps two orders of magnitude at the extreme between the surface of the mixed layer and its base. Along with additional variability in light availability due to the passing of clouds and the day-night cycle, this creates problems for the functioning and balanced metabolism of a phytoplanktonic cell.

Calcification could also benefit coccolithophores by providing them with an additional rapidly inducible energy sink under high-light conditions, preventing photodamage at little nutrient cost. Vast excess production of coccoliths is often observed in blooms of E. huxleyi, when many more coccoliths are produced than are required to complete a single covering of the cell, leading first of all to multiple layers of coccoliths around cells and finally to mass shedding of free coccoliths into the surrounding water .

Phytoplankton living at the ocean surface are often nutrient-limited and could potentially benefit from sinking into nutrient-rich deeper waters. The ballast provided by the coccosphere accelerates the sinking rate of coccolithophores about 10-fold, consistent with a hydrodynamic role for calcification in nutrient capture. In addition to the ballast effect, a higher degree of per-cell calcification (or PIC/POC ratio) usually coincides with increasing cell size, which further accelerates sinking velocities.

The most compelling hypothesis for the existence of the coccosphere is to provide an armor that protects the cell from predation, either by shielding against “penetrators” that enter and subsequently lyse the cell or by reducing, if not preventing, incorporation by “ingestors.”

coccolithophores defense.jpegcoccolithophores defense.jpeg
Proposed main benefits of calcification in coccolithophores.
(A) Accelerated photosynthesis includes CCM (1) and enhanced light uptake via scattering of scarce photons for deep-dwelling species (2). (B) Protection from photodamage includes sunshade protection from ultraviolet (UV) light and photosynthetic active radiation (PAR) (1) and energy dissipation under high-light conditions (2). (C) Armor protection includes protection against viral/bacterial infections (1) and grazing by selective (2) and nonselective (3) grazers.

Penetrators comprise a large variety of planktonic organisms from different functional groups. The smallest ones are viruses that can terminate blooms of E. huxleyi . To infect coccolithophores, viruses need to pass through the coccosphere to reach the cell membrane. In E. huxleyi, perforations within and between coccoliths are usually smaller than 200 nm and packed with polysaccharides so that coccoliths pose an effective barrier to viral infections.

The geological record supports the idea of an initial protective function for calcification, as coccolithophores appeared in the Triassic at virtually the same time as a second armored plankton group, the dinoflagellates, in the aftermath of the most severe mass extinction in the history of life, the end-Permian extinction (252 Ma). The simultaneous appearance of these two armored plankton groups is strong evidence of a major reorganization within oceanic plankton. This also most likely reflects an increased predation pressure in the newly emergent marine ecosystems, which more broadly featured the appearance of novel and more effective predation that drove morphological and behavioral restructuring, in particular with the selection of infaunal modes of life and more effective defensive skeletons.

Changes in seawater chemistry associated with CO2-induced acidification could primarily affect coccolithophores in two ways: an increase in CO2 availability and an increase in hydrogen ion concentrations (decreased pH). The former alters photosynthetic carbon acquisition, whereas the latter can influence both calcification and photosynthesis of coccolithophores (56). Most of the culture studies performed on different species indicate that coccolithophore photosynthesis in some species is mildly stimulated and that cell division rate slightly decreased at elevated CO2/reduced pH. Because cell division rate is a key factor in determining fitness, the latter may put coccolithophores at a competitive disadvantage with acidification, although net population growth rates will be determined by relative mortality losses.

It's not known whether these environmental changes in surface ocean conditions benefit or disadvantage coccolithophores depends on how they affect the fitness of coccolithophores in relation to the fitness of their main competitors and the nature of their predators.

The least calcified morphotypes of E. huxleyi and Gephyrocapsa were generally found in waters with the lowest CO32− concentration in one study, but in a second study, the most heavily calcified morphotypes of E. huxleyi were more abundant in the season with the most acidic (lowest saturation state) conditions.

Coccolithophore calcification is a highly demanding energy process, with the cost varying among species and with environmental conditions. Benefits associated with UV light and grazing protections have relatively well-supported evidence, whereas other potential benefits, such as light uptake and protection against viral/bacterial infection, are still very hypothetical. However, we conclude that although reduction in grazing pressure might have been the likely initial reason for why coccolithophores calcify, other benefits led to a substantial diversification in the different niches. The variability in calcification functions is consistent with the observed diversity and distribution of coccolithophores in the ocean, where placolith-bearing coccolithophores dominate in the subpolar regions (suggesting a function of grazing protection, depending on the location of light uptake and viral/bacterial protection), and Umbellosphaera and Discosphaera grow preferentially in the subtropical regions (suggesting mostly a function of viral/bacterial protection). Meanwhile, the haploid-diploid life cycle in coccolithophores is still poorly understood. The regular association of life stages with different biomineralization modes (typically heterococcoliths versus holococcoliths) also indicates a variability in the functions of calcification where the various coccolith morphologies produced within a single species during different life stages allow adaptation to different ecological niches.




Because coccolithophores pursue a variety of growth and protective strategies that allow them to flourish in waters ranging from oligotrophic* recycling systems to eutrophic** systems, their response to global oceanic change is likely to differ between the actual members of the calcifying phytoplanktonic group. And it is interesting to note their individual morphologies and modes of protection as well as their abilities to sink in direct proportion to their individual mass.

* Oligotrophic:
Lacking in plant nutrients and having a large amount of dissolved oxygen throughout. Used of a pond or lake.
Being deficient in nutrition
Being deficient in plant nutrients, such as nitrogen or phosphorus

** Eutrophic:
Rich in mineral and organic nutrients that promote a proliferation of algae and aquatic plants, resulting in a reduction of dissolved oxygen. Used of a lake or pond.
Being rich in nutrients and minerals and therefore having an excessive growth of algae and thus a diminished oxygen content to the detriment of other organisms.
Promoting nutrition.
( both definitions from The American Heritage® Dictionary of the English Language, 5th Edition)