JC010: Mud volcanoes and submarine canyons


Cruise diary

Day 8: Thursday 28 June 2007
Position: 38°14.296N 09°23.392W (Google Earth reference: 38 14’3”N 09 23’4”W)
Weather: Sunny with light cloud

Tina writes:

Things I like best:
The motion of the boat: Rough or smooth, I love it, I have never slept better.

The people on the boat:  A really great bunch, well most of the time, that is, when they are not trying to persuade me to have an extra scoop of ice cream.  I have the will power of a snail when it comes to things like this.

The scientific work: Where else do you get to see something NO ONE has ever seen before?  The colours are amazing, the fauna new to me. I would love to discover more about the different fauna and flora here and work out the feeding relationships and other dependencies.

Photos taken during yesterday's Isis dive:

Things that most bug me: 

Not being able to move any of the monitors. This is mine fixed solidly (upside down).  Of course I understand why and believe me I am more than happy not to have monitors flying around when it gets choppy. But I do like to be able to position my monitors.

Not having another three weeks on board. Back to school soon, and of course I’m missing you guys, but another three weeks would really enhance my knowledge of the deep-sea environment. 

Today we:

Sent down the CTD 

Sent down the SAPS (Stand Alone Pumping System)

Sent down the ROV to carry out a reconnaissance of both sides of a canyon.

Richard writes:

"The ROV was on dive number 60 when I started my shift. Each dive Isis makes is meticulously planned and the objectives of this dive were to:

1. Complete a video transect (this means taking a video of the seafloor as Isis ‘flies’ above it, at a relatively stable height of 1-2m and then up a steep slope (1700m –1000m) in the Setúbal / Lisbon Canyon. (The slope was so steep that Isis travlelled 85m upwards but only 0.5m forward. Imagine trying to ride your bike up that!)

2. Collect push cores from the canyon floor

3. Collect some plants and animals to study on the surface

4. Put in an oxygen chamber experiment, as long as there were the right conditions and animals for this.

It is extremely enjoyable watching the live footage of the deep sea. There were corals, sponges, eels, jellyfish, bi-valves (two shelled animals like clams or mussels) octopi and other fish. Whilst some of the plants and animals are similar in appearance to those I see in the shallow seas when I dive, some are completely different looking. Sponges and bi-valves were brought up to the surface and will be used like this:

  • Sponge tissue samples for phylogenetic study (working out relationships between species) at Ghent University.
  • Rachel will perform stable isotope analysis to find out what position the animals are in their food chains.
  • Other samples will be preserved in formalin to help with identification work.

Unfortunately there were also a lot of plastic bags. According to Andy Wheeler, who researches and lectures at University College Cork, “this is sadly typical of most places on the European margin where we have looked”.

Some countries, such as the Republic of Ireland, have taken measures to reduce this. Ireland introduced a ‘plastic bag tax’ several years ago (if you need a plastic bag in a shop it will cost you €0.15) to reduce the amount of plastic bags used. Unfortunately this has not stopped the problem altogether. Additionally, plastic bags are not biodegradable (will not be broken down by microorganisms and so the problem will remain for a long time even if no more bags are thrown in the sea.

Currents within the oceans can lead to underwater transportation across international waters. This shows that people from all across the world need to work together to take care of the environment. One problem for wildlife is that, in the sea, plastic bags fill with water and hang upside down. Animals such as turtles think that they are jellyfish (they do look very similar from a distance) and eat them and this then blocks their intestines leading to a very painful death. If you search the internet you can find lots of facts, figures (thousands of marine animals die because of this each year) and pictures about this. This quote jumped out at me: "The leatherback turtle can keep itself warm in cold water, dive over 1000 meters below sea level, travel thousands of miles and gulp down a Portuguese man-of-war (a deadly jellyfish) but is threatened by the inert (lifeless) plastic shopping bag" - Mrosovsky (1987).

So next time you get offered a plastic bag in a shop, think about whether you really need it or not. Then think about all the animals that may be at risk if the bag ends up in the wrong place after you have finished with it… 

Reference: Mrosovsky, N. (1987) Pivotal temperatures for loggerhead turtles (Caretta. caretta) from northern and southern nesting beaches. Canadian Journal of. Zoology, 66:661-669

Life on the canyon floor

ROV at work

Rubbish in the canyon

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