Monday, 16 July 2012

Day 8 - Foreign observers

3am start – yuck!  I have been assisting with processing the megacores for prokaryote analysis. These are organisms that don’t have a cell nucleus (like bacteria for example). I have also been involved in work with the microbial sampling and CTD operations (Conductivity – salinity, Temperature and Depth). 

This work involves collecting water from 12 sample depths using the CTD rosette.  As the CTD is lowered through the water column, the data is streamed live to a computer screen where we can see profiles of temperature, salinity, depth, oxygen, chlorophyll and turbidity.  The sensors in the CTD are rated so that they can travel to depths of up to 6000m.  The 10 litre niskin bottles are then fired on the way back up to the surface.  The water is collected and either processed immediately or stored in 2°C to help slow down degradation. 

Annette filters water samples
Ten litres from each depth is then filtered through a two-stage filtration unit.  Water first passes through a GF/F filter to sample algae and phytoplankton.  The second filter, which is contained within a sterile plastic tube, collects free-living and particle bound prokaryotes.  The filters are then stored at minus 80°C.  DNA and RNA will be extracted from these filters back at the lab to assess the microbial community composition and functioning in the water column from the Porcupine Abyssal Plain. 

These communities essentially control a big part of the carbon cycle, linking the atmosphere to the sea.  Some of organic matter produced by the phytoplankton on the surface sinks to deeper depths and is processed and digested by the prokaryote communities converting it to back to simpler forms of carbon like CO2. This process results in CO2 being transporting from the surface to the ocean’s depths, including its sediments.  Understanding the composition and structure of these communities at different parts of the water column therefore helps inform as to why we see variations in the transport of carbon to deeper depths. 

I am on board as a foreign observer under the Foreign Vessel Observer Scheme managed by the Irish Marine Institute.  Under the United Nations Convention on Laws of the Sea (UNCLOS), the Marine Institute has the authority to place Irish observers on foreign research vessels in Irish waters, like this one.  My role as an observer is to report and document the research activities carried out on board.  In this role, I also ensure that the type of research work and the area under investigation conforms with the official notification documents submitted by that country to the Irish Government and act as an official channel in the case of communications between the vessel and the Irish Government, should the need arise.

Observers also take an active part in the research work being carried out.  I am currently doing a PhD in Biological Oceanography at the National University of Ireland, Galway and will be taking this opportunity to learn as much as possible from everyone on board and hopefully be able to use some of the data, methods and techniques I witness in my own work.  The foreign observer scheme is a great way for undergraduate and postgraduate students to gain seagoing experience and to collect data.  More information on the scheme can be found at www.marine.ie

Annette Wilson, PhD Student at NUI Galway and Foreign Scientific Observer for Marine Institute, Ireland.