Annelida- Segmented worms

I had my second invertebrates practical today, and I got to practice my biological drawing (which I find oddly therapeutic). The organisms we looked at were from the phylum Annelida (comes from the Latin "ringed"), which are segmented worms. Not quite as cool a name as Platyhelminthes, the flatworms, but they can be equally as odd to look at. Phylum Annelida includes the lug worm, responsible for the nice squiggly sand patterns you see on the beach at low tide, and rag worms, commonly used as fishing bait.

The lab we were in had the faint smell of slightly mouldy fish, which was understandable considering all the specimens were dead and in trays under microscopes, right under our noses.

 This looks like a plant, but it is in fact a worm, and it is apparently found only around cold hydrocarbon seep sites on the upper Louisiana Slope in the northern Gulf of Mexico and form groups of hundreds to thousands of individuals. These worms harbour internal chemoautotrophic sulphide-oxidising (thiotrophic) symbiont. 

This was taken down a microscope (which is really quite hard to do well if you don't have an extremely steady hand), and it shows just how vast the size differences in segmented worms are. The picture below is a close-up shot, using the macro setting, of these worms. As you can see, they really are tiny- about 3mm long!

Here is the rag worm! this was a whopper, I think it was about 15cm long. These make up the majority of the worms farmed for the fishing bait industry. The picture below doesn't quite show the large, lethal looking jaws, but it does give some idea of how odd they look.

This rather cute thing is nicknamed the 'sea mouse', and you can see why. It is horribly difficult to draw biologically, as the only real feature you can see is hair, which you're not actually supposed to draw (because it's too much detail). My favourite part of this beauty is the iridescent hair round its sides.

This the organism responsible for the nice sand squiggles at low tide- the lug worm. It had a lovely set of gills, which looked like they were made out of shiny strips of copper. We learned last lecture that they build their casing by covering themselves in mucus and rolling around in their sand tunnel. Which quite frankly sounds disgusting.

This photo, again taken down a microscope, shows that the feature that defines Annelida, segmentation, can be really quite subtle. This specimen only shows a vague outline of its segments.

And here are my biological drawings from that practical:

In my ocean and earth systems lecture this morning, we learned about Snowball Earth, which has always been one of my favourite events in Earth's history. For those of you who haven't heard of it, it's a period of time in which Earth was completely covered in ice, and a series of volcanic eruption melted it back to what it is today. Snowball Earth is so significant because the reason why life survived the event was due to the properties of water- hydrogen bonding between water molecules makes it freeze less dense, resulting in ice being buoyant. Because it is buoyant, all the sea ice and glaciers developed on the surface, preserving and protecting life below the surface from the extreme temperatures above. 

It's really quite incredible that hydrogen bonds saved all life about 2 billions years ago- without them, there might not be humans here today.

On that bombshell, I'll leave it at that. Goodbye!

Photos

Bit belated, but I've been a little bit too busy/lazy to do this post lately!
Recently we did our first practical, which involved walking around the large lab, having a look at some dead (and live) specimens, and having a go at some biological drawing. Biological drawing is, in a way, easier than normal, artistic drawing, because it only requires features that help in the process of identifying the organism. The rules around how you draw the organism, however, are much more strict. For example, the brief guide we were given says that artistic shading is NEVER allowed.

I looked a bit weird dunking my camera into the anemone tank, but I managed to get some quite good photos in my opinion. I've also posted one of my biological drawings. There are a lot of photos, but I'll do my best to explain them!

 All these blue photos were taken from outside the tropical coral tank in the reception area, and it's a small exhibition of coral fluorescence under UV (which is why the tank looks blue)

 It took me quite a while to get a close up of the clownfish, as they moved quite quickly, and this is perhaps the best one. They look quite grumpy, which makes me a little more fond of them.

 By far my favourite photograph of all of the ones I took that day is this one. This is a young starfish, and it is only about 2-3mm across, which just shows you how good the macro setting can be now!

I got some strange looks taking these pictures, and someone even said "I do hope that's waterproof". Nevertheless, dunking an expensive camera into water is still unnerving.

This is a close up of a sponge. A lot of people know that bath sponges used to be made of actual sponges, but not many people know that to get them into a state so that you can use them, the fishermen had to beat the sponges on rocks to break up and wash out the spicules. More on spicules later.

This belongs to the phylum sipuncula. I Did a biological drawing of this, which I shall post here later

These are the spicules taken from a sponge. This photo was taken through a microscope eyepiece, which required patience and a steady hand! Spicules basically make up the skeleton of the sponge, though are not actually bones (which is why it's not an invertebrate). You don't want to use a sponge as a sponge if it still has its spicules, they're like shards of glass. Speaking of glass, spicules are usually made out calcium compounds, but in the rare deep sea sponges, they are silicates because calcium is dissolved much easier below 1500m. So deep sea sponges grow glass shards. How terrifying.

This is the "skeleton" of a sponge, with all its spicules in position. Below, you can see a close-up of this, but you still can't properly see the individual spicules. I love the pattern they make.

More spicules. As you can see, their shape varies quite a bit.

A close-up of coral. I do think their structure is really quite beautiful.

A "forest" of coral. This skeleton is what is left in bleached coral- when the surrounding water gets too hot for the coral, which then expels the beneficial algae (which gives coral their spectacular colours). The coral cannot live without the algae, so it dies, and its white skeleton is left.

This is an interesting story. This used to be feared by sailors because it resembled the bloated hands and feet of dead children (nice image). It's actually a sponge that grows on the shells of hermit crabs, and gradually dissolves their shell until it becomes their shell. This actual specimen had a large hermit crab in it once.

And here's the photo of said hermit crab, when it was alive!

This is a slice of Anemonia viridis, which is obviously an anemone. Below I have posted the sort of thing we were asked to do.

I quite like this one because of the blue bits, which to my understanding are part of the anemone's collar, retracted into bundles so the tentacles are out.

This is a close-up of the anemone's mouth. I'd never seen its mouth before, so this was particularly interesting. It didn't really do much aside wiggling the tentacle you see near its mouth.

I have yet to find out what this actually is. It's one of the strangest things I've seen in the reception tank, as each blobby thing looks like a lobster eye. The colours were amazing, too.

That's it for today, I hope you enjoyed the pictures. I have been told I have an invertebrates practical next week, too, so I'll bring my camera along to that too. The workload is slowly increasing, but I think I'm managing to keep on top of it. I enjoy the information in some lectures so much sometimes that we have discussions on the bus home while we wait for the freight train to cross.

I love it here, I feel like I am in my element! (But I am looking forward to coming home for Christmas. I miss my double bed). Anyway that's really it. I'll post sometime next week, as I've worked out the posting weekly works best for me. So long!

A week in

Looks like my most recent blog didn't publish!

What I was supposed to tell you:

We have so far learned about sea sponges, sea fans, flatworms (Platyhelminthes, what a great name!), jellyfish, corals, sea gooseberries and other relatively simple but, in my opinion, very interesting organisms.

I found in the news a couple of days ago what I believe is a brilliant article relevant to my course: http://www.bbc.co.uk/news/science-environment-24398394 

Take a look to see the sorts of things I've been learning about.

In other modules I've learned about hydrothermal vents (think of an underwater volcano, throwing out superheated water about 350 degrees Celsius and ions such as iron). These can give rise to some extremely weird deep-sea life forms such as eye-less prawns (instead they have a large light-sensing organ on their backs), snails with metal scales on their feet (the metal is secreted by the cells on their foot as a way of filtering out heavy metals that are present in large amounts in the water near hydrothermal vents), and "Yeti crabs". These crabs are one of my favourite deep-sea organisms; they have hairy arms that give them their nickname.

From top to bottom: deep-sea prawn, scaly snail, and Yeti crab. The prawn and the snail have yet to be named

We also took a trip out into the Solent on the University's smaller research vessel, the Callista, for a bit of a taster into working scientifically with boats. We measured, with a Secchi disk, how far the light penetrated the water (not very far. The maximum we got was 2m because it was cloudy and not very bright). We then measured the temperature and salinity using a CTD probe (C stands for conductivity. They use this instead of salinity for obvious reasons!).

By far the best part of the trip was the trawl. We dragged a small net along the Solent sea floor for a couple of minutes and brought up a crate full of sea weed, mud, and some interesting animals. Here's what we found:

Sea spiders

Swimming crab

Shore crab

Spider crab

Goby fish

Shrimp

We also found a whopper hermit crab, the only thing I managed to take a photograph of.

 Here's the crate of stuff

Here's the hermit crab. He wasn't very cooperative, and this was the most we saw of him unfortunately.

I have a practical tomorrow, and I'll take my camera along to that and take some photographs. The lecturer will be bringing in some specimens (dead and alive I think) of the Cnidaria phylum. This phylum contains Jellyfish, siphonophores (Portuguese man o' war. It's not a true jellyfish because it's a colony of polyps, not just one), sea anemones, corals, etc.

I'm really looking forward to the practical (mainly because I get to wear my own lab coat and use my own dissection kit!) and I just hope I remember my camera! 

See you all soon,

Lots of love xxx