Trained as an applied mathematician, I am passionate about understanding biological systems. Mathematics offers powerful tools to distill complex biological problems, while statistics enables the extraction of insights from data. I use both disciplines in my work on ecology and biology. Here are some of the problems I have explored and published:
One of the most widespread patterns on Earth, spanning oceans in both hemispheres, is the elusive Redfield C:N:P ratio, which describes the proportion of carbon (C), nitrogen (N), and phosphorus (P). This ratio underpins major planetary biogeochemical cycles and involves three elements essential to all known life forms. In 1934, Alfred Redfield, a Harvard physiologist-turned-oceanographer, empirically discovered a consistent ratio of 16 N atoms for every P atom in the deep ocean. Remarkably, he found the same N:P ratio in the collective mass of phytoplankton, the microscopic organisms responsible for producing over half of the oxygen we breathe.
Why 16? For the past eight decades, this question has been challenging to answer, despite accumulating empirical evidence that broadly supports this pattern, even though deviations from 16 have been observed in different ocean regions and plankton species. In 2011, James Elser and I provided the first theoretical explanation for the origin of the N:P=16 ratio in Ecology Letters. We demonstrated that this pattern emerges at the macromolecular level, where evolutionarily fixed structures essential to all life—ribosomes and RNA polymerase proteins—are inherently interdependent in their biosynthesis.
The next question is how this atomic pattern, originating at subcellular and macromolecular scales, propagates to the global scale. In 2010, I developed a model addressing this question, though I have not yet published the proof. However, this year, I introduced a mathematical framework called the Iterative Chemostat, which connects the synthesis of information-bearing biopolymers (nucleic acids and proteins) to nutrient cycling. This framework lays the groundwork for proving Alfred Redfield's original hypothesis that one of the planet's largest stoichiometric patterns arises from the inner workings of one of the smallest living structures—a photosynthetic cell.
In the late 1990s, during my PhD studies in mathematics, I had the opportunity to explore the theory of Ecological Stoichiometry in James Elser's lab. This theory led me to deduce that rising CO2 levels would globally deplete essential minerals in plant tissues, including those in edible parts like grains. More importantly, it allowed me to connect this nutrient depletion to human nutrition.
In 2002, I published a hypothesis suggesting that increasing atmospheric CO2 levels would "intensify the already acute problem of micronutrient malnutrition." Given that iron (Fe), zinc (Zn), and iodine (I) were already deficient in human diets, these nutrients received special attention in my paper. However, at that time, experimental data were limited, making it difficult to empirically validate the hypothesis. It took about 12 years to gather sufficient evidence from CO2 experiments conducted by dedicated researchers in Australia, Asia, Europe, and the United States to confirm that rising CO2 indeed depletes minerals in the plants foundational to human nutrition.
My 2014 meta-analysis demonstrated that essential mineral levels, including calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), phosphorus (P), and zinc (Zn), decline in a wide range of crops and wild plants (known as C3 plants). This mineral depletion is geographically widespread and systemic throughout plant tissues. This discovery was made possible by data from experiments that grew plants under elevated CO2 and controlled conditions, conducted by hundreds of researchers. Their collective efforts produced enough data—7,761 pairs of observations, totaling over 15,000 observations—to uncover the hidden shift in plant quality caused by rising carbon dioxide levels.
Furthermore, I theorize that this decline in plant quality on a planetary scale exacerbates not only mineral undernutrition but also calorie overnutrition, contributing to both "hidden hunger" and obesity. More recently, in collaboration with colleagues from Ireland, Columbia University, and Bryan, we published new findings on the decline of carotenoids—crucial for eye and brain health—in plant tissues exposed to elevated CO2.
Any questions or comments? Email: loladze@gmail.com (this is my prefered email rather than my Bryan work email)
I usually reply within 48 hours. If urgent, please, let me know in the subject of the email, and I'll respond ASAP: loladze@gmail.com
You are also welcome to DM me @twitter: @loladze