Sea urchin fertilisation and more cataloguing

I had actually been timetabled for the sea urchin lab that was held before the Easter holidays, but being the idiot I am, I got the time wrong and ended up missing it, so I turned up to this weeks one instead. And I was not disappointed. Today's practical was I think the most fun one we've had so far (the deep sea one, however, wins the prize for the most interesting lab).

The aim of the practical was to investigate how the chance of success of fertilisation of Psammechinus miliaris, the green sea urchin, changes with concentration of sperm. To do this, we had to make live specimens spawn, which involved injecting them with KCl. This part was quite risky because not only was it difficult to inject them properly, KCl can cause heart attacks in humans (if enough is injected). I didn't particularly enjoy feeling the crunch as the needle went in through the Aristotle's lantern (a complex mouth-like contraption made of calcareous material).

The needle was supposed to go through the hole in the centre of the dark ring, but as they had 'shut' their Aristotle's lanterns, we had to inject it diagonally through the dark ring you can see above.

Here's proof I was actually doing the experiment. 

Below is a video of the urchin's reaction after being injected with KCl solution. It's not writhing about in pain because they don't have a complex nervous system, don't worry, and this happens to them in the wild (just not with a needle)

After 15-20 mins, the urchins released a milky white substance. Females released eggs that were visible to the naked eye, so easily identified under a microscope (one of the reasons this experiment is popular in universities running biology-related courses). Below is a photo of what they looked like after spawning:

We then collected several samples of this solution, from both males and females, and diluted the male spawn so there was a series of decreasing concentrations. The eggs from the female spawn were then added (all the same concentrations) and left for 10 minutes. After this, the percentage of fertilised eggs was counted under the microscope. What we saw was really quite amazing.

Above is a video taken with my camera down the optical lens of the microscope, zoomed in a bit so it's a bit blurry, but what you can see is sea urchin sperm.

Sea urchin eggs, magnified by 10x

Eggs, magnified by 20x

This photo really made me realise how amazing what we were doing was; what you can see is a fertilised egg. You can tell by the ring around it. Later on, we actually saw some divide. This was our first successful fertilisation- our first sea urchin babies!

You can see various stages of fertilisation here, but more notably is the egg in the middle, 2/3 up the page, that has undergone its first division.

More eggs, the bottom one is definitely fertilised, the top one is not.

A random phytoplankton cell. These microscopic algae look enormous compared to the sperm and eggs.

This is my favourite photo of the day. The egg cell on the top has just been fertilised, the one beneath it has undergone 2 divisions. You can see four cells. As cheesy as it sounds, it did hit me that we had created life, and it seemed a bit of a shame to waste it. But sea urchins are capable of releasing billions of eggs/sperm in their lifetime, so it's not massively wasteful compared to the millions of eggs/sperm that get carried away and not fertilised in the wild.

I loved this practical, it made me feel like a PROPER scientist, and I hope we get to do something like this again. After the practical, Sarah and I went to the Discovery Collection again to do more cataloguing, and we found these adorable squid:

Ok this is more terrifying than adorable, these are the suckers on a squid. They have loads of tiny, really sharp teeth on them. I think the species is a Humboldt squid, but I'm not sure. If you want to try googling it yourself, the species is either Todarodes saggitatus or Todaropsis eblanae (I can't remember)

The tiniest squid I have ever seen, I think Neorossia caroli or possibly Sepiolidae. 

Thanks for reading again, I'm about to start exams so will be busy for a few weeks, apologies for that. I hope you have enjoyed reading this and the photographs, etc, as I have greatly enjoyed learning it!

The Discovery Collection- Cephalopods

I spent this afternoon with Sarah at the NOC, cataloguing the cephalopods. Cephalopods include squids and octopodi, and are by far my favourite group of organisms.There is such a wide variety of physical features, such as the unevenly sized eyes of cock-eyed squids and the photophores of the umbrella and firefly squids.

I don't think I've posted a photograph of the room yet- this is where all the specimens are stored.

The dots on this squid are photophores. They are light emitting organs and they give it its nickname, the jewel squid. Below is a photo of a live umbrella squid with the photophores lit up:

We found these little squids in a near-impossible to open tub. There were about 50 specimens in the tub altogether! When we handled them, they felt quite rubbery and odd.

This giant spider crab was contained in a tub with a 40cm diameter. Its leg span is therefore about 80cm. Huge.

 These specimens are flying squid.

Another flying squid!

Cataloguing the deep sea

Today I had the fortune of cataloguing deep sea specimens from the Discovery collection for Dr Tammy Horton, one of the world's leading amphipod experts. I didn't think I'd be saying that a year ago! I feel incredibly lucky to have these opportunities virtually on my door step, and I like switching off while writing out new labels for specimens such as Centromedon zoe (a species which Dr Horton named and first described). It also not only improves your taxonomy but vastly improves your ability to read bad handwriting.

Amphipods (derived from the Greek word for 'different' and the Latin, poda, for 'foot') are an order malacostracan crustacea. They look like the sand hoppers Talitrus saltator you find on the beach when the tide is about halfway out and can vary in size from mere millimetres in length to the largest recorded of 28cm (found at a depth of 5,300m in the Pacific ocean). Their main characteristic is the absence of a carapace, which is the head 'plate' you see in lobsters.

This is what I used to imagine being a 'proper' scientist would involve, and to actually be able to do this makes me feel both nerdy (in a good way, of course) and lucky. The specimens were kept in jars and we were given the task of copying their labels (which were often faded or written in dreadful handwriting) into a notebook as a record of the specimens kept at the NOC Discovery collection.

This small amphipod was actually one of the largest I handled today. It was one of my favourites due to its larger size enabling me to see most of its features. It still feels strange reading a label and realising that the specimen is older than me.

I also got to write out the labels for various hydrozoa and hydroids. 

I may have found an opportunity to volunteer in the live aquarium lab at the NOC, and if I am able to I will definitely post some more photos because it holds one of the oldest captive lobsters in Britain (maybe even Europe). We were taken to the lab during a tour of the NOC on the open day last year and it looked like an interesting place to work and study.

Hopefully the next time I post, I will have heard back about the lobster tagging placement. I'm doing a VHF radio course this weekend as part of the requirements for it, so I hope that goes well. I also had an exam this week and a load of coursework deadlines so it has been a bit stressful but it turns out I got a 2:1 in the exam, so silver linings and such.

A lesson in deep sea biology

In our lab today, we got to have a look at some rare, interesting and extremely ugly specimens from the deep sea.

My favourites included Histioteuthis, a squid that lives in a depth range between 200-1000m. For this rather large range it has 2 different sized eyes- the small one takes in light from the shallower areas and the large one allows more light in in deeper areas, which I found out a couple of years ago is also why pirates used to wear eye patches (so they can see above and below deck!).

There are a couple of photos of the actual specimen we looked at below, but the photo above allows a much better comparison of the eyes, so you can see there is a massive difference in their size.

Another was a fish with bioluminescent organs (photophores) under its eyes that act as headlights. I would love the opportunity to study bioluminescence in the future, it's an extremely interesting subject. Many of these organisms features in the photographs I have posted live in the deep Pacific, namely the Mariana trench-the deepest place on Earth. Only two people have visited this depth before, one of them being director James Cameron- fewer people have been in the deepest part of the ocean than on the surface of the moon. Let that sink in a little, and you will understand why I love this part of marine biology.

Bioluminescence is used for a range of things, mainly though for attracting pray, warning predators to keep away, and blending in with their surroundings. An example of the latter is a fish that lives in waters just above its predators (the twilight zone). It has photophores on its belly that emit light of the same colour and brightness as the water above it, basically erasing its own silhouette against what little light reaches down.

Some prawns have bioluminescent vomit that they throw up all over their predators, to confuse and choke them, allowing them to escape.

I could go on for hours, honestly, and I will probably write another post on this when I work out how to add photos from my phone. I hope you have enjoyed reading this as much as I have enjoyed learning about it and writing it!

This specimen is older than me!

A lot of deep sea fish have long, thin teeth, which make it easier for them to catch and hold onto prey, because in the dark often if the prey escapes, it's gone for good.

This is one of several species of deep sea fish that grow light-producing organs (photophores) under their eyes to act as headlights. In most cases, they emit blue light as it travels furthest in the dark, but some predators emit red light that only they can see- red light is absorbed first and so many organisms cannot see it.

This specimen was one I encountered a couple of weeks ago when I was helping out the deep sea department with their cataloguing. It is the squid with one eye bigger than the other. It was so big I had to take two photos to show the difference in size.

The pictures below give you an idea of what the photophores look like when the organisms are alive:

The red prawn on the right is adapted to deep sea conditions in two ways:

1. Its body is red in colour. This is because its predators cannot see red, which makes it invisible to them.

2. It vomits bioluminescent goo in the face of its predator, which blinds, confuses and sometimes chokes it, meaning it can escape.

There are some organisms that have photophores for unknown reasons, and I think this may be a subject area I would like to continue my studies in.

Exams finally over!

So, it's been a while, and I have been terribly busy with exams, but they've all finished now and I'm free.
The timetable for this semester isn't certain yet, but I've had my first marine ecology lecture and it looks as though it will be a fantastic unit. We will be covering one biome every lecture, ranging from the shallow, rocky shores to the deep sea (possibly my favourite biome).
Today, we also had a physical oceanography lecture by Dr Siman Boxall, who has featured on Channel 4 documentaries about the 2004 and Japan tsunamis and who I feel very lucky to have as a lecturer. He showed us a few slides from a project he participated in, Cape Farewell, where he took several artists such as musician KT Tunstall and comedian Marcus Brigstocke to the Arctic. His aim was, through the inspiration the artists got from their time in the Arctic, to inform people of the reality of the shrinking sea ice. I found it both humbling and fascinating, and some of the things the artists came up with, including projecting words onto icebergs and jumping into the freezing (-1°C) sea in a survival suit and just "drifting", were really creative.
If you would like to have a look at the fantastic project, here's a link with more information:
http://www.capefarewell.com/

I have a sea survival course coming up around Easter, and I am hoping to bring my camera with me to document some of it. There will be more boatwork, too, which I am looking forward to, and there will also be more practicals soon, although I'm not entirely sure what they will involve.

Update on the Hobbit tshirt competition: I have completed it and am now the proud owner of the tshirt, which I will post a picture of a bit later.

Other than that, there's not really an awful lot of interesting things I can report as I have basically been living in the library for the past three weeks. Unpleasant but worth it, because now the exams are over. I promise to have a more interesting entry next time!