Le plastique c'est fantastique

Or so goes a by French band Elmer Food Beat. Probably for different reasons (see the video!), but I agree: plastic is fantastic! Imagine if all plastic vanished all of a sudden. You would have no mouse to navigate away from this page (argh!)... but I would not have had a computer keyboard to write it with anyway. And the list goes on; much modern living depends on plastics and rubbers: computers, ipods, wellies, shoes soles, fleeces, DVDs, skateboard wheels, bottles, fridges, washing machines, cars, bikes... all rely heavily on these wonderful materials!

Plastic and rubber, was ist das?
Plastic and rubber are amorphous (disordered, noncrystalline) materials whose basic microscopic units are polymers: long chains of identical molecules, stringed together like a necklace. Such a chain is shown below in Fig. 1 for polystyrene, which is made from little styrene molecule units. These units are known as the polymer's monomers (mono=1, poly=many). Also shown below is an expanded polysterene cup for soy sauce from a japanese takeaway, which is what about 10 to the power of 24, or Avogadro's number or a million million million million of these polystyrene chains look like from our macroscopic point of view.

Fig. 1. Polystyrene is a polymeric material which at molecularly consists of chains of styrene units. It can be moulded and expanded to make a light cup

Why plastic and rubber?
Because microscopically they consist of these little moecular chains, plastic and rubber have unique properties compared to other materials like wood, metal or glass. For example, the shock absorbing properties and gripping properties of rubber tyres, whether full of air or solid, are a blessing to anyone who cycles. Imagine cycling on a bumpy road with wheels like in Leonardo's famous prototype! (see a reconstruction below). The schock absorbing and gripping properties of rubber derive from the fact the polymers are like lots of small springs, entangled together like a spagetti in a bowl of pasta.

So plastics are light, but strong, they can be easily coloured or made opaque or transparent. Rubbers are elastic and grippy. Both of them are cheap to manufacture (at least at the moment, see below). But what is the ecological impact of man made plastics? Are they all "toxics", like in the Story of Stuff presentation . Answers in the next post! In the mean time, enjoy the Story of Stuff (probably better to watch in the website, but I also embed youtube version below).

Welcome to the Ecophysiolog!

Welcome! I created this blog to put in writing some thoughts on the science behind domestic, local and, on occasion, global ecological matters. I am a biological physicist/mathematical biologist in the field of algal biofluids. I research the individual and collective biased swimming dynanics of microscopic bacteria and algae. To put the last sentence in plain English, I am a scientist who studies the motion of single celled green algae (phytoplankton) and bacteria in fluids, and their responses (taxes) to environmental cues like light, food, gravity, flow etc.. For example, the skewed mass distribution inside some swimming green algae such as Chlamydomonas or Dunaliella causes them to focus in plumes (see picture below), a responseknown as gyrotaxis.

picture left (by O. A. Croze [me!], ABBL): macroscopically, the swimming gives rise to this beautiful pattern in a small petri dish. video right (by S. O'Malley and O. A. Croze, ABBL): a high speed video of the alga Dunaliella salina swimming. The picture and video were taken at the Algae Biofuels and Biofluids Lab (ABBL) at the University of Glasgow.

My research could have interesting implications for understanding plankton blooms in the Ocean (see the spectacular image below of a Coccolithophore bloom near Ireland) and also the processing of swimming algae to make products, such the nutrient supplement and dye Beta-carotene and, it is hoped, biodiesel and hydrogen. Algal biofuel technologies are not mature yet, but understanding the strange behaviour of fluids of swimming algae could help.

My current work with algae is connected to renewable energy, since there is the prospect of using these cells to make biodiesel and even hydrogen, but also for the formation of plankton blooms of swimming algae in the ocean.

picture left (Wagenigen University): a pilot raceway pond algal bioreactore at Wagenigen University in the Netherlands. picture right (NASA/GSFC) plankton blooms around the British Isles and North West France. The patches you see off the coast of England and Ireland are blooms of the species E. huxleyi a coccolithophore with a hard shell (that doesn't swim: not all microalgae do!).

In this blog, I will talk about my research, but in the main I hope to investigate the science behind ecological issues such as recycling, public transport or energetic self-sufficiency on a domestic or local scale. My musings hope to be be educational and should benefit anyone interested in debunking some green living myths or dilemmas (such as "should I wash my plastic bottles and cans before recycling them?", or questions like "why can't all types of plastic be recycled at my local bin/centre?". I will approach these issues from a scientific standpoint.