Day 9
Overnight we have taken several cores. Once opened, they are like textbooks revealing the venting history of this area.
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| Date: | 9 August 2009 |
| Weather conditions: | overcast, slightly foggy |
| Temperature (air / water): | 7.4/ 6.9 °C dew point = 6.8 °C |
| Wind speed: | 6.5m/s |
| Wave height: | relatively calm |
| Location: | 73°N, 8°E |
Daily report:
Last night it was the turn of the geologists and geochemists (and a few microbiologists to keep them company!). We took several gravity cores from different points around the hydrothermal vent field. Opened up, these cores have revealed fascinating information about the history of venting in this area - a kind of natural textbook. There are clearly differentiated stripes that probably have different mineral compositions. Rolf says that each may represent a venting event with different temperatures. There is no question that they will provide invaluable information that will further our understanding of Loki's Castle.
Tamara and Kirsten have been up all night processing the new material. They have been collecting both pore water and solid samples for further study.
During the last ROV dive yesterday we planted two collections of logs to be artificial growth substrates. Since the first discovery of vent communities in 1977, and with that the discovery of ecosystems based on chemical energy instead of light energy (chemosynthesis), researchers have been identifying chemosynthetic ecosystems in other situations, such as cold seeps.
One question that researchers puzzle over is how do chemosynthetic organisms travel from one vent or seep to another? One hypothesis has been that they use temporary chemical energy sources such as whale carcasses (whale falls), or the remains of other organic materials such as wood (wooden ships). Since one cannot predict where a whale carcass might be, or a sunken log, researchers are now deliberately setting out such material. Christoffer Schander, a researcher at CGB, has established a kind of network with the coast guard along the Scandinavian coastline, whereby he is informed of any whale strandings or floating carcasses, and these are then sunk in identifiable locations so that they can be studied over the years to come - a whale fall study is a long lasting experiment!
Hans Tore made up two small collections of logs using different types of wood that the ROV has placed near "Sleepy", one of the active chimneys at Loki's Castle. These will be analysed in the coming years to see what kind of organisms are settling and colonising the wooden substrate.
The Discovery team continues to be active. They took advantage of the very calm seas yesterday afternoon and were out in the RIB (zodiac) to film the ROV recovery after the dive and the G.O.Sars from the water. Today they are out on the bow attaching their camera to the bow winch in order to take unique footage of the bow from a bird's eye perspective. We have been told that we will be met by a helicopter as we approach land and Tromsø, Tuesday morning. There will be a camera person on board the helicopter to take unique footage of the G.O.Sars "at sea".
Today we are going to take another CTD to further the process of characterising the vent plume, and then an ROV to collect more chimney material - or maybe more biological material! We will be working as efficiently as possible because tonight the wind will start to pick up from just a few meters per second to 15!
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