CMEC goes to sea - Blogs – University of Copenhagen

CMEC > News and media > Press releases and CMEC news > CMEC goes to sea - Blogs

04 September 2012

CMEC goes to sea - Blogs

September 9th

The art of filtering water

by Erik Askov Mousing
A large part of our work here is water filtration. Indeed, almost every marine biologist or biological oceanographer can tell you stories about water filtration. There is even a scientific discussion (and dispute) about how it is best done.

We are interested in the concentration of phytoplankton, because phytoplankton is the primary producers of marine systems and thus the basis of all further steps in the food chain (zooplankton, fish, etc.). In addition, phytoplankton plays a part in the global carbon cycle and therefore also in climate change.

In order to get this information we filter a known volume of water on a filter and extract the pigment chlorophyll a. All phytoplankton contain chlorophyll a and the concentration of this pigment can therefore be used as a proxy for the phytoplankton concentration.

By using filters with different pore sizes we can split the phytoplankton into different size groups and investigate the community size composition. The community size composition is interesting because it is thought to directly affect the oceans ability the uptake CO2 and we seek to understand and quantify this link.

Until now we have filtered 250 water samples and tomorrow, if the weather allows it, we will filter more.

September 8th

The Ocean thermal inertia and the global climate

by Mohamed Adjou
If there is a good place to feel the Oceanic thermal inertia, that could be the Polar Regions. Among all the screens on our navigation board for the Radar, the GPS and other fascinating geographic and meteorological counters, what keeps my attention is the surface water and the air temperature displayed continuously.

4.6°C in the water and 0°C in the air 

Since we approached the latitudes near 68°N, the surface water has become distinctly warmer than the air. We even crossed narrow streams where the sea surface temperature was up to 6°C higher than the air’s temperature.

This difference is due to the thermodynamic characteristics of water and air. Under normal conditions, 1 kg (~1 liter) of water can store a quantity of heat, up to four times higher than 1 kg (~1000 liters) of air. The water’s heat conserving capacity and the fact that the Ocean is approximately 255 times heavier than the atmosphere, explains how the Ocean creates “a warm bath” in the Polar Regions under a freezing atmosphere!

At the global scale, the tremendous Ocean thermal inertia buffers the stability of the earth climate. That inertia causes climate lag-responses to global climate forcing, for cooling or warming. Indeed, the change in amount of heat stored in the ocean as a result of global warming is much greater than the change which has occurred in air.

September 7th

It all started with hand drawn maps and silver cutlery

by Katherine Richardson
Nowhere do I feel my age – or at least the passage of time – more acutely than on a research cruise. The advances surrounding marine research that have taken place over my career are breathtaking. When I started in this game, we had no chance of knowing where the sensors or bottles were in the water. The depth of the sensors was estimated on the basis of the wire angle and 3rd grade geometry.

Today, we follow the progess of our sensors in real time on a computer screen and close sampling bottles by pushing a button while sitting in a warm dry lab rather than standing on a platform over the edge of the ship and waiting to “feel” the bottle close with a slight tug on the wire. Collected data is plotted in real time, converted to power points and shared with others at evening lectures. Previously, this data analysis took months. Figures were then hand drawn, sent to a graphic artist and, finally, to a photographer so slides could be produced in order to present the data for others.

The change in the ways of doing the science seems, however, small compared to the change in the culture and life on board. I remember fondly one of my old professors continually hanging over a strip chart marking time every 30 minutes so we could reconstruct surface temperatures and salinities when we got home. But perhaps the greatest change, is seen at the Captain’s table. In the old days, it was just that with a white linen tablecloth and – at least on the British ships of my early career days – real silver cutlery and teapot. No one sat at the Captain’s table without an invitation – and they were few and far between. No one is sitting at the Captain’s table on this cruise either – not even the Captain! Instead, it bears the fruit bowl (also something new!) and it is here the breakfast muesli (another innovation) is set out.

I am certainly not lamenting the passage of the “good old days”! I like this brave new world in almost all respects. I guess the only thing I really miss on the “modern” research cruise is the sense of being close to nature and the sea – you simply can’t feel the salt spray on your skin while sitting in front of a computer…

September 6th

Preindustrial CO2 concentrations

by Mohamed Adjou

Bad weather is upon us again so we are sailing north to escape it. We will reach the next sampling transect in a day and half a day where “beautiful” weather is supposed to be waiting for us.

While sailing I make discrete measurements of the carbon dioxide pressure (pCO2) in the seawater. In the air, the pCO2 is relatively stable as the global atmosphere is mixed within a few days and having a value of just over 380 ppm nowadays. However, in the Ocean it is markedly variable with its turnover taking centuries or millennia.

The polar area where we are, namely the Arctic ocean, is a sink of CO2 which means the ocean is absorbing this greenhouse gas. Our records show that in fact the CO2 pressure in the seawater is about a quarter to a third less than in the air, similar to the air CO2 concentration during the preindustrial. Anecdotally, a colleague heard me saying “277 ppm of CO2“ and asked me with exclamation if it was in the air; I replied of course not. That would be a preindustrial dream!

September 5th

After the storm

by Erik Askov Mousing

In a time where the impact of humans on the Earth becomes more and more present (global warming, loss of biodiversity, introduction of invasive species etc.), it feels reassuring when elements have an impact on you. It is however, bad timing when it happens in the Atlantic Ocean between Iceland and Greenland.

Yesterday, the strong wind limited our sampling to the first station. However, we did managed to collect water from the surface and the Deep Chlorophyll Max (DCM) which is the depth where the largest subsurface concentration of phytoplankton is positioned.

Today, we woke up to a beautiful sunrise to the east and the east coast of Greenland to the west. During the night, we had entered the East Greenland current, which transports break-off icebergs south. Due to the storm we ventured further north than planned and arranged a new transect with 5 stations. All of these went well. We measure primary production (an estimate of the rate of new production made by phytoplankton), max chlorophyll a (a proxy for total phytoplankton biomass), fractionated chlorophyll a (a proxy for the community size distribution), filtrations for picoeucariots (to be used for genetic diversity studies) and water samples for species identification. In addition, we measure water chemistry such as salinity, nutrient concentration, CO2 and O2 partial pressure etc.

Shelter and samples - exciting times!

by Katherine Richardson
YES! There IS shelter close to the Greenland Coast! There are also icebergs, beautiful snow covered mountains and a glacier that runs right down to the ocean as well as a flock of dolphins jumping and playing right in front of the ship! This is why I became a marine scientist! We’re getting lots of samples on board and all of those who were seasick yesterday are up and about today. Forgotten are the boredom and unpleasantness of yesterday’s storm.

We are now in a region where the surface water is strongly influenced by melting ice and we are getting entirely different readings on our measurements than we did in the “warm” (about 10 degree) waters west of Iceland. The surface water contains much less CO2 than the air, so there is a strong potential for CO2 uptake here – it will be exciting to see how much my phytoplankton are contributing to that process.

September 4th

Feeling small in the big ocean

by Katherine Richardson

We are heading from Iceland to Greenland in a strong gale. Right now our entire world consists of dark water, big waves and spindrift. Nothing else will make you feel smaller. After just 1,5 stations we've had to stop sampling, as the harsh weather poses too big a risk on the equipment and the crew.

DANA is a very 'lively' ship leaning up to 30 degrees in the wind. The sight of people walking up and down the stairs leaning the opposite way is a magnificent sight, and our bigget and perhaps only entertainment these days are the 'potholes' the captain steers the ship into during dinner. However, going on the second week of the cruise, the fun starts to wear off.

The plan now is to sail to the coast of Greenland, where we hope to work in shelter of the wind and get back on track with our sampling!

About the cruise

Several CMEC researchers are off on a 3 week long trip on-board the research and monitoring vessel DANA. The first week they sail from Hirtshals in Denmark to Reykjavik in Iceland, with a focus on teaching activities for undergraduates, graduates and PhD's. The following two weeks are dedicated research.

Linking phytoplankton and climate change

The CMEC project, which is led by Professor Katherine Richardson, investigates phytoplankton diversity and primary production and how these factors affect the carbon cycle in the ocean and the exchange of inorganic carbon with the atmosphere. The carbon cycle in the ocean is closely linked to the global carbon cycle which plays an essential role in climate change. It is therefore important to investigate and quantify the effect of biological processes in order to get a thorough understanding of how phytoplankton affect and is affected by climate change, now and in the future.

Photo: Sine Fredslund