Posted by: Andrew Guerin | April 13, 2008

Attack of the killer sea anemones

ResearchBlogging.orgMarine anemones are often admired for their colourful beauty (although some are, admittedly, rather drab), but people are often surprised to hear that they are actually animals. They are in fact members of the cnidarians, a group of animals which all possess a cell type known as cnidocytes – cells which can fire barbed stingers into any prey which brush against them – hence the stings of jellyfish, who are also members of this group (you might think of an anemone as being something like an upside-down jellyfish, attached to a solid substrate). Like jellyfish, they are muscular, and can move about to an extent, depending on the species. Their behaviour can be fascinating. Some species even engage in vicious (if slow-motion) combat with other members of their species when they come into contact.

Many anemones are omnivorous suspension feeders, meaning that they obtain their food from suspended particles in the water column as they are washed over their tentacles, but they will take all manner of organic detritus when they can get it. Some will also consume any small organisms unfortunate to blunder into their stinging tentacles, such as amphipods and other small crustaceans. Two such anemone species are Cereus pedunculatus, which lives partly buried in sediment with its tentacles projecting from the surface, and Calliactis parasitica, which lives attached to the shells of hermit crabs and gastropods. Under normal conditions, these two species are typical mild-mannered suspension feeders, but once the level of dissolved oxygen in the water begins to drop, things start to change……..
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Posted by: Andrew Guerin | April 1, 2008

What killed the mammoths?

ResearchBlogging.orgAccording to the evidence we have, the woolly mammoth Mammuthus primigenius disappeared about 3600 years ago; pretty recently in the grand scheme of things.

For some time now, debate has raged over why, exactly, they disappeared.
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Posted by: Andrew Guerin | February 12, 2008

Darwin Day commemmorative post: On phenotypic penis plasticity
“It’s only that short because I’ve been living in a location where I’m exposed to high turbulent flow”.

This might sound like a useful defence, but alas it is only valid if you happen to be a barnacle.

Today’s post is in honour of the birth of Charles Darwin, 199 years ago today. While you might be doubtful that an article about penises is appropriate for Darwin Day, I assure you it is; Mr Darwin spent a considerable amount of time studying barnacles (discovering numerous species and learning much about their biology) and I’m sure he’d be fascinated by the research outlined in this recent paper by Neufeld and Palmer (as he would be by the many advances in biology that have occurred since his time). Darwin even gets a name-check in the paper!

It’s a fairly well known pub-quiz-question fact that of all the animals on Earth, barnacles have the largest penises relative to their body size Read More…

Posted by: Andrew Guerin | January 16, 2008

Comparing fish feeding on rigs and reefs

Blogging on Peer-Reviewed Research

One of the longest running controversies in artificial reef research has come to be known as the ‘attraction versus production’ debate. This concerns the high densities of fish often found around artificial reefs (in many cases greater than those around natural reefs). The question, essentially, is this: are these high densities the result simply of attraction of fish from the surrounding areas (which might be undesirable), or do artificial reefs actually provide additional useful resources which translate into increases in fish biomass?
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