Marine

One of the longest oceanographic time series in the world

December 16, 2011 by sfraser No Comments | Category Marine Directorate general, Marine Directorate Science

The Marine Scotland research vessel Scotia set sail on Sunday 11 December with 10 scientists on board. This cruise will add to time series of measurements from the deep and cold waters of the Faroe-Shetland Channel that were started by scientists more than 100 years ago.

In 1895, Dr H. N. Dickson published the results of his research in the Faroe-Shetland Channel, showing how changes in the physical environment could have an effect on the distribution of our important fish stocks. Since then the monitoring has continued and is now one of the longest oceanographic time series in the world, providing information essential to understanding climate change and the health and productivity of Scottish waters.

The ship was to be loaded with an array of highly technical scientific equipment, most of which would not be recognisable to those early researchers. This equipment to be used includes instruments such as a thermosalinograph, which measures the surface temperature, salinity and chlorophyll (green plant pigment) concentration whilst the ship is at sea, and a sampling carousel which has sensors for conductivity (for salinity calculations), temperature, depth, oxygen, chlorophyll and water turbidity, as well as water sampling bottles. This CTD (short for Conductivity-Temperature-Depth) package is lowered through the water column whilst the ship remains in a fixed location to measure profiles of temperature and salinity in the Faroe Shetland Channel and collect water samples to determine its chemical composition. Scientists will also deploy acoustic current meters onto the sea bed up to a depth of 800 m, to measure vertical profiles of the current speed and direction flowing in the channel.

Some photos of the sampling equipment are below. Reversing bottles are still in use today but were superseded in the early 1990s by the present-day water measurement and water sampling equipment (a CTD and water sampling carousel) particularly when sampling at multiple depths throughout the water column. Acoustic Doppler Current Profilers (ADCPs) are moored on the sea bed and measure the current speed and direction at preset levels up through the water column to the surface.

All of these data collected will be analysed by researchers back in the Marine Laboratory and are very important for understanding the so-called “meridional overturning circulation” (MOC), responsible for the transport of heat in the oceans around the globe (with a large impact on our climate), as well as to quantify climate change in the ocean. This analysis contributes to important publications on ocean status, such as the International Council for the Exploration of the Sea (ICES) Report on Ocean Climate which is free to download from the ICES website: (http://www.ices.dk/pubs/crr/crr309/ICES%20SCREEN%20PDFs/ICRR%20309-inner-singles.pdf) and to EU research efforts such as the “ThermoHaline Overturning – at Risk?” (THOR) project (www.eu-thor.eu).

Further information on the Scotia and the oceanographic time series can be found at the links below ;

Scotia:

http://www.scotland.gov.uk/Resource/Doc/295194/0099704.pdf

Longest oceanographic time series in the world:

http://www.scotland.gov.uk/Resource/Doc/295194/0099699.pdf

Contributed by Alejandro Gallego, Sarah Hughes and Barbara Berx

Tags: climate change, Monitoring, sampling bottles, Scotia, Time series

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