Biological dispersal shapes species' distribution and affects their coexistence. The spread of organisms governs the dynamics of invasive species, the spread of pathogens, and the shifts in species ranges due to climate or environmental change. Despite its relevance for fundamental ecological processes, however, replicated experimentation on biological dispersal is lacking, and current assessme...

The importance of water-air interfaces (WAI) on microorganism activities has been recognized by many researchers. In this paper, we report a novel phenomenon: the entrapment of ciliates Tetrahymena at the WAI. We first characterized the behavior of cells at the interface and showed that the cells' swimming velocity was considerably reduced at the WAI. To verify the possible causes of the entrap...

Diatoms are the primary source of nutrition and energy for the Southern Ocean ecosystem. Microalgae, including diatoms, synthesise biological macromolecules such as lipids, proteins and carbohydrates for growth, reproduction and acclimation to prevailing environmental conditions. Here we show that three key species of Southern Ocean diatom (Fragilariopsis cylindrus, Chaetoceros simplex and Pseu...

Observations of the microtubular 'km' system and filamentous ' M ' systems in living specimens of Stentor coerulens show that on contraction of the body both systems shorten, thicken and remain straight, but that on initial relaxation they behave differently: the km fibres begin to lengthen later than the M fibres, the latter being thrown into sinuous folds. Electron microscopy of specimens coo...

Systematic studies of phenotypic diversity--required for understanding evolution--lag behind investigations of genetic diversity. Here we develop a quantitative approach to studying behavioral diversity, which we apply to swimming of the ciliate Tetrahymena. We measure the full-lifetime behavior of hundreds of individual organisms at high temporal resolution, over several generations and in div...

1Department of Physics and Astronomy, University College London, Gower Street, LondonWC1E 6BT, UK 2Laboratoire d’Etudes Spatiales et d’Instrumentation en Astrophysique (LESIA), Observatoire de Paris, CNRS, UPMC Univ. Paris 06, Univ. Paris-Diderot, 5 place Jules Janssen, Meudon Cedex 92195, France 3Atmospheric, Oceanic and Planetary Physics, Clarendon Laboratory, University of Oxford, Parks Road...

We have been invited to a wedding by Ken Wilber. This ceremony is not to be an inconsequential affair, but rather resembles a Royal Wedding with all its pomp and circumstance. The marriage, it has been announced, will result in the unification of two previously combative kingdoms into one domain, a cause for much rejoicing. Yet as the guests assemble and the ceremony begins, I find myselffilled...