For Immediate Release: September 1, 2015
Providence, R.I. – Dr. John H. Costello, professor of biology at Providence College and lead author of the research paper, “Multi-jet propulsion organized by clonal development in a colonial siphonophore” has been published in Nature Communications, an international online journal.
The paper’s focus is on colonies of highly mobile, jellyfish-like organisms, called physonect siphonophores, that are powerfully propelled through the oceans by older colony members, while younger individuals up front provide the steering. This division of labor among different developmental stages is thought to be key to the colonies’ success.
Siphonophores- gelatinous planktonic organisms related to jellyfish, anemones and corals- have the most complex colony-level organization of any animal. One such species, Nanomia bijuga, is a voracious predator made up of a number of specialized individuals, called zooids, that each work together to survive. At the front of the colony are a series of genetically identical zooids called nectophores, which make up the propulsive engine of the organism known as the nectosome, operating like jets by pumping water backwards. Towed behind this are the zooids that specialize in reproduction and feeding.
Dr. Costello and his colleagues used image tracking to investigate how exactly this multi-jet propulsion system works in N. bijuga and discovered that the younger, smaller nectophores growing at the front manoeuvre the colony use their jets to influence its direction. In contrast, the older, larger nectophores provide forward or reverse thrust to propel the colony during its daily migration.
This pattern ensures that all members of the colony, young and old, perform important tasks and their developmental organization allows for cooperation.
The authors suggest that this simple and efficient means of multi-engine organization could influence the design of underwater propulsion vehicles.
Along with Dr. Costello, the other scientists include, Dr. Sean P. Colin ’93, Roger Williams University; Dr. Brad Gemmell, University of South Florida; Dr. John Dabiri, Stanford University; and Dr. Kelley Sutherland, University of Oregon.
*Dr. Costello is also an Adjunct Scientist and Whitman Center Investigator at the Marine Biological Laboratory (MBL) in Woods Hole, Mass. Here's the article from the MBL : Marine Animal Colony is a Multi-Jet Swimming Machine, Scientists Report.