September-December, 2012 
SCAMIT Newsletter 
Vol. 31 Nos. 3-4 
ocean become super-saturated and it used to be thought that sponges had to remain in the top 
1000m due to this fact, but that has turned out not to be true and they extend down to 4000m. 
Sponge shape will often be determined by habitat. For instance, in rocky habitats, sponges tend 
to be flat. In muddy areas they tend to be stalked. Cobble habitat is usually inhabited by foliose 
sponges while boulders and large cobbles often have shelf sponges. And, large rocks can support 
barrel shaped sponges. There is often confusion interpreting collection labels for e.g., barrel vs 
vase. 
There is the potential for smaller species living on bigger species, with epizoic complexes being 
common. It is relatively easy to distinguish two sponge species growing on top of each other 
when they are alive and in the field, but once preserved and colorless, the task becomes much 
more difficult. Without knowing it, the taxonomist could be cutting through two species thereby 
finding confusing spicules when examining the slide prep. 
With this chilling announcement regarding confusing species, Dave went on to give examples. On 
one sponge he found 7 other little species growing on it, all within 1 inch. Additionally, he found 
7 or 8 species on one small 1/2 inch rock. 
Dave admitted that currently he is doing 19* century biology - cutting things up and looking at 
spicules under a microscope. 
And sponges are much more complex than just their spicules. Sponge larvae contain bacteria, 
collagen fibers, and a small packet of spicules from which to start. But as taxonomists we are only 
looking at spicules which is a limited aspect of the animal. There is a wide variety of “soft stuff’ 
involved which we don’t examine. Studies have shown some indication that there are specific 
bacteria which are accepted at the surface of the sponge; bacteria live within the mesophyll in 
cells, in endocytes, all over the places. What is the symbiotic relationship between the bacteria 
and the sponge? There is some thought that the bacteria might control the shape of spicules. It has 
been found that in some sponges 2/3 of their biomass can be microorganisms. 
Another interesting aspect of sponges is their biochemistry. There is now some work being done 
to try to use their specific biochemistry as taxonomic indicators. Predators of sponges have picked 
up on the biochemistry aspect. Dorids, for example, Diaulula, can chemically sense the specific 
sponge they need. The compound is water soluble and they can “sniff’ them out. Research 
suggests that they are extremely specific and will not prey upon similar species even within the 
same genus. 
The skeleton of sponges, with regards to size and shape, can be affected by environmental factors 
such as season and depth. Additionally levels of silicon in the environment can affect skeletal 
development as well, e.g., width of the spicules. So, short and thin spicules and short and fat 
spicules can exist in the same species depending on the time of the year. The same species can 
have multiple forms/morphology based on its location, time of year, ocean chemistry, predation, 
etc. At this point in the day, many wanna-be sponge taxonomists were shaking their heads in mild 
despair. 
Dave feels that you need SEM images for proper spicule detail. Due to so many difficulties facing 
sponge taxonomists, he estimates it takes about $ 100/specimen to get to Family. This number 
does not factor in SEM cost, collection time/efifort, preservation, sorting, glass ware/labels, 
and final identification. People need to be trained on how to separate the multiple specimens 
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Publication Date: 6 July 2016 
