Life’s Secretive Pioneers in the Sandy Pits
Many animals love to explore or spend most of their lives in the gaps and spaces created by piles of stones or wood: some cats like confined spaces, mice certainly do, and ants just love them. But ants can, of course, make use of much, much smaller crevices than bigger animals can. However, what about the sand on the beach? It is fine and seems compact, but there is always a small volume of interstitial space between the sand grains: could anything possibly be living in there? I bet no beach-frolicking folk ever think about that, but sure, further down the beach towards the sub-littoral you can step on shells buried in the sand and may get bitten on the toe by a crab that has sheltered in the substrate while further up, along the zone of decaying algal debris, you may encounter beach-hoppers and sand flies. But in between these two horizontal layers, would there be any life at all in the sand? —>
Dogs are after you !
Although most humans have a relatively big nose right in the centre of their face, that organ’s main function seem to be there to support the spectacles and to pre-warm the air that enters the nostrils. Our sense of smell isn’t exactly great when it comes to a showdown with other nose-possessing organisms, but when I use the plural “we”, I am not exactly accurate, for female noses consistently outperform those of males and there are even odours that men and children cannot but mature women can smell. There is also the aspect that in women odour thresholds vary over the menstrual cycle. Generally speaking, however, we humans aren’t smell champions and find it hard to understand how a police dog can follow the track of a wrongdoer or a lost person, how salmons sniff out their home rivers on their migrations to their birth stream, how ants smell odour trails laid down by worker ants and how male moths can possibly detect the scent of a female 10 km away.
And spiralling around as well
A look at the diminutive, fantastically diverse life forms and their activity in a single drop of water can be a truly amazing experience – provided of course you have not chosen tap or rainwater. A drop of water from the edge of a weedy pond (or a puddle near a penguin rookery, which was my source for a study) examined under a simple light microscope does, however, reveal a microcosm of hidden life. In amongst the jittering soup of miniature plants and animals, it is the group of ciliated protozoans that are the greatest attention getters. The smallest may not even reach 50 microns, while Paramaecium and Euplotes maximally attain 1 mm and the biggest like Spirostomum may reach a length of 3-4 mm.