Hermit Crab with Anemone pals
The delight in systems thinking is that it provides novel opportunities to observe interactions that would not be revealed in reductionist evaluation of data targeted at a specific hypothesis. More systems thinking was evident in the recent Aquatic Noise conference I attended in den Haag, Netherlands, and fortunately it seems to be a trend in scientific research.
A case in point was an innovative study by Julie Oswald (et. al) trying to tease out auditory thresholds of a humpback whale. One of the more vexing data gaps in marine bio-acoustics is not knowing the hearing thresholds of baleen whales. This is due to the fact that the two methods of determining auditory thresholds – “operant conditioning,” and “Audio Evoked Potential” (AEP) require a subject in captivity.
Even supposing you could get a 45-ton humpback whale into a training arena, training it to perform for a food reward (operant conditioning) is a mind-boggling proposition. AEP would present other challenges because the subject needs to be still, typically on a deck, out of water to fixture with electrodes.
But Dr. Oswald came up with a brilliant alternative. In the behavioral repertoire of any sentient being subject to predation is “the startle response” when some unexpected stimulus crosses some perceptual threshold. Her thought was that she might be able to record this response in a tagged whale (instrumented with an accelerometer and some acoustical recording equipment) when the whale was exposed to a startling noise. Varying the frequencies might tell us something about what frequencies the whales can, and can’t hear.
A fabulous idea. Unfortunately, not all fabulous ideas work out, so her results were not conclusive.
Another novel presentation by Marta Solé (et. al) involved an attempt to acoustically disrupt an adorable relationship. It is pretty well known that hermit crabs move out of their scavenged shells and into incrementally larger shells as they grow. Some hermit crabs have life-long relationships with sea anemones which ride on their shells in some clever mutuality, presumably involving food and protection. So when a hermit crab moves out of a shell and into a larger shell, it needs to remove and relocate its anemone pal(s).
Playing loud, low frequency sounds disrupted this relationship, which in her words “brings an additional contribution to the understanding of the effects of noise on marine ecosystems.”
As indicated in a previous piece, the door of this systems thinking has been opened because we can now synthesize vast amounts of data, which we can return to when we come up with a different way of thinking about it. Until recently research focused on acquiring “clean data” that clearly illustrated a hypothesis. Now the data can have a lot of grey edges which reveal more complicated relationships. Sort of like real life.
