“Take that out of your mouth.”

October 21, 2008
Image courtesy Wikimedia Commons

Image courtesy Wikimedia Commons

Such is the cry of parents whose young children have an appetite for learning that is sometimes too literal. Over the last year or two we have seen an increase of stories about the effects of toxic plastics on human health, from fetal to adult. The scientist Jacques Monod once commented of genetics, “What’s true for e-coli is true for an elephant.” That goes for the effects of plastics, too.

Approximately no one should be surprised that the oceans absorb much of our chemical trash. Still, it was a useful and insightful exercise for Charles James Moore, of the Algalita Marine Research Foundation, to quantify just how much plastic the waters have absorbed – and by extension, the life within them. Moore finds that for two decades we have been flushing plastics out to sea faster than industry produces them for their infinite commercial use.

Bisphenol-A, singled out recently in several studies for harm to children, is just one chemical that seeps into marine ecosystems. Styrene, polycarbonates, UV stabilizers, non-stick coatings all break-down over time, but for the most part maintain their molecular integrity. When a foam coffee cup dematerializes to the four corners of the Earth, it doesn’t disappear, but soaks up other toxins before entering the food chain. Scientists have identified 267 species worldwide that ingest plastic debris, including albatross, fulmars, shearwaters, and petrels, which confuse plastic for food; 44 percent of seabird species; and sea turtles that munch on plastic bags and fishing line.

Moore identifies eight issues within the overall problem:

  • Macroscopic debris – diapers, syringes, etc – washes up on beaches, unsightly and potentially harmful.
  • Bags, lines, and other waste snares marine biota, “and kills through drowning, strangulation, dragging, and reduction of feeding efficiency.”
  • Some plastic debris looks like and weighs as much as food, but is only a toxic substitute.
  • Hydrocarbon-based synthetic compounds tend not to biodegrade. They can also provide a home to barnacles, worms, and other undesirables, and float them across the sea, where they become invasive species.
  • Many unprocessed plastics are shipped from suppliers to factories in the form of tiny resin pellets. At sea, these pellets and other plastic debris emit and absorb endocrine disrupters and other pollutants.
  • Debris falls through the water column and disrupts both benthic ecosystems and deep-sea deposition of CO2.
  • Coastal species see their nursery habitats poisoned by anthropogenic litter.
  • Plastic waste clogs ship intake ports and wraps propellers, costing time and money.

SOURCE: Moore, Charles James. “Synthetic polymers in the marine environment: A rapidly increasing, long-term threat.” Environmental Research 108 (2008): 131-139.


The Jellyfish that Lit the World

October 8, 2008
The edge of Aequorea victoria's umbrella contains a bioluminscent protein called aequorin.

Aequorea victoria

A scientific adventure that began with a haul of 10,000 bioluminescent jellyfish off Friday Harbor during 1961 has resulted in the 2008 Nobel Prize in Chemistry.

Osamu Shimomura‘s career shot forward in 1956 when he isolated a luminescent protein found in the mollusc Cypridina. This was a major feat for a young researcher, particularly since U.S. scientists had worked without success for some time on it. Princeton University snapped up Shimomura, who was awarded a PhD from Nagoya University without even being a doctoral candidate. He now works at Connecticut College.

Once in the U.S., Shimomura turned his attention to the jellyfish Aequorea victoria. Over the course of 1961, he and a colleague gathered and sliced the edges off 10,000 jellyfish — the parts that glow — and mashed them into a condensed form. Back at the lab, the scientists discovered that the material glowed brightly, when activated by the calcium ions in seawater. They named this brightening protein aequorin.

Aequorin contains a chromophore that has become a pivotal investigatory tool for biochemical researchers around the world. This “beer-can-shaped” protein absorbs blue and ultraviolet light, then re-emits it at a green wavelength.

Today, scientists use this molecular flashlight to illuminate cancer tumors as they grow, track the progression of Alzheimer’s, and map the basic function of cells. With Green Fluorescent Protein, researchers can watch a single protein move about a cell.

Shimomura shares the prize, one-third each, with colleagues Marty Chalfie of Columbia University and Roger Tsien of UC-San Diego.

(Image courtesy: The GFP Site)