Level 1 — Absolute Beginner
Long before humans made plastic, nature already had its own plastic.
Tiny bacteria make this natural plastic and store it inside their bodies.
Scientists found that many animals can eat and break down this natural plastic.
Animals like starfish, worms, and earthworms can all do this.
- nature
- the physical world, including plants, animals, and the environment
- plastic
- a material that can be shaped, often made from chemicals
- bacteria
- very small living things that can only be seen with a microscope
- store
- to keep something for later use
- break down
- to separate something into smaller, simpler parts
- starfish
- a sea animal shaped like a star
- worm
- a long, thin animal with no legs
- energy
- the power needed to do work or stay alive
Level 2 — Elementary
Long before humans invented plastic, nature had already created its own version. Many bacteria and other microorganisms produce natural biodegradable plastics called PHAs, storing them inside their cells as reserves of carbon and energy.
A new study by researchers at the Max Planck Institute for Marine Microbiology in Germany found that dozens of animal species carry enzymes capable of breaking down these microbial PHAs, a skill once thought to belong only to microorganisms.
The animals identified range widely, including marine worms, starfish, and land dwelling earthworms, suggesting the ability to digest PHAs is far more common across the animal kingdom than scientists had previously realized.
The findings, published in the journal Nature Ecology and Evolution, suggest that animals may have been quietly feeding on these microbial carbon reserves for hundreds of millions of years, gaining access to an energy source once thought to be off limits to them.
- microorganism
- a very small living thing, such as bacteria
- biodegradable
- able to be broken down naturally by living organisms
- reserve
- a supply of something kept for future use
- enzyme
- a protein that speeds up a chemical reaction in living things
- digest
- to break down food or material inside the body
- dwelling
- living or existing in a particular place
- carbon
- a chemical element found in all living things
- journal
- a magazine that publishes scientific research
Level 3 — Intermediate
Long before humans engineered synthetic plastics, microbial life had already perfected a biodegradable alternative. Many bacteria and archaea produce polyhydroxyalkanoates, or PHAs, storing them intracellularly as reserves of carbon and metabolic energy that can be drawn upon when external nutrients become scarce.
A study led by researchers at the Max Planck Institute for Marine Microbiology in Bremen, Germany, has now shown that this microbial carbon reserve is not entirely off limits to animals. The team identified enzymes capable of degrading microbial PHAs across dozens of animal species, a capability previously assumed to be restricted to microorganisms and a small number of specialized decomposers.
The animals carrying these enzymes span a remarkably broad taxonomic range, including marine worms, starfish, and terrestrial earthworms and springtails, indicating that the capacity to access this carbon source evolved, or was retained, far more widely across the animal kingdom than previously appreciated.
Published in Nature Ecology and Evolution, the findings imply that animals, working alongside decomposing microorganisms, may have been quietly exploiting these biological carbon reserves for hundreds of millions of years, a previously overlooked ecological pathway with implications for how scientists understand nutrient cycling in both marine and terrestrial food webs.
- synthetic
- made artificially rather than occurring naturally
- archaea
- a group of single celled microorganisms distinct from bacteria
- intracellularly
- occurring or located within a cell
- metabolic
- relating to the chemical processes that keep an organism alive
- decomposer
- an organism that breaks down dead material into simpler substances
- taxonomic
- relating to the classification of living things into groups
- terrestrial
- relating to land, rather than water or air
- nutrient cycling
- the movement of essential elements through an ecosystem
Level 4 — Advanced
Long before industrial chemistry engineered synthetic polymers, microbial metabolism had already arrived at a biodegradable analogue: many bacteria and archaea synthesize polyhydroxyalkanoates, or PHAs, sequestering them intracellularly as carbon and energy reserves that can be mobilized during periods of nutrient scarcity, functioning much as fat reserves do in animals.
A study led by investigators at the Max Planck Institute for Marine Microbiology in Bremen now demonstrates that this microbial reserve is not, as long assumed, biologically sequestered from the wider food web. The team catalogued enzymes competent to hydrolyze microbial PHAs across dozens of animal taxa, a degradative capability previously presumed to be the near exclusive province of microorganisms and a narrow set of specialized decomposers.
The phylogenetic breadth of species carrying these enzymes, spanning marine polychaete worms and echinoderms such as starfish to terrestrial oligochaetes and collembolans, indicates that the capacity to access this carbon pool either evolved convergently across highly divergent lineages or, more parsimoniously, was retained from a considerably more ancient common capability than previously recognized, an interpretation the authors favor given the trait's phylogenetic dispersion.
Published in Nature Ecology and Evolution, the findings recast a previously invisible ecological pathway: animals, operating alongside decomposing microbial communities, may have been tapping this biologically synthesized carbon reservoir for hundreds of millions of years, a revision with material implications for models of nutrient cycling across both marine and terrestrial ecosystems, and one that underscores how readily a resource long considered microbiologically self-contained can prove, on closer molecular scrutiny, to be embedded within a far wider trophic network.
- polymer
- a large molecule made of many repeated smaller units
- sequester
- to isolate or set apart, often storing something for later use
- hydrolyze
- to break down a substance chemically through reaction with water
- phylogenetic
- relating to the evolutionary relationships among species
- convergently
- occurring independently in unrelated lineages, arriving at similar outcomes
- parsimoniously
- in the simplest way that accounts for the evidence, avoiding unnecessary assumptions
- trophic
- relating to feeding and nutrition within an ecosystem
- reservoir
- a stored supply or source of something available for later use
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