By Inge Deschepper and Daniel Gebregiorgis Yirgaw |
We are almost through half of our trip from North to South and we are starting to gain a better knowledge of the different water masses that we are passing over using CTD (conductivity, temperature and depth profiler) measurements and other instruments. We have observed the Mediterranean outflow water (MOW) as we passed the Bay of Biscay and the Strait of Gibraltar change into the Mauritanian shelf water (MSW) and the Antarctic Intermediate water (AIW) as we head into equatorial regions. We start to ponder on what we are truly seeing and what we can contribute to the study of Climate Change.
Climate Change predictions are based on data collected throughout many years and proxy data (e.g. sediment and ice cores) that goes back 100’s of thousands of years! What we are investigating is more on the changes that are occurring now in the atmosphere and how can we see these changes in the measurements that we are taking? There are many students on board RV Polarstern from many different science backgrounds: biology, hydrology, physics, biogeochemistry, oceanography, climatology and paleooceanography. This spurs an interest in many different aspects of the ocean.
We have been given a task to think of what we can investigate with the data that we are collecting on the transect. Some groups are interested in how the water masses are distributed, whilst others are interested in the influence of the ENSO (El Niño Southern Oscillation) on the West African monsoon. Other groups are interested in the changing heat and salt content of the water masses and how they have changed over the years. All of these topics are affected by the changing climate. For example, the changing air temperatures and warming of the surface waters, enhances the stratification (the layering) of the upper ocean and consequentially leads to reduction in marine productivity (the oceans plant food) and ocean ventilation. The heating of the surface waters may also affect the distribution of different water masses in regions that we are expecting to see upwelling of deep, nutrient rich water.
All of these questions try to assess the impact of Climate change on the Oceans now and try to see the change latitudinally over time.
About the authors:
Inge Deschepper: I am a Ph.D. student at Laval University, Quebec and my studies are on the modelling of biogeochemical cycles in the Hudson bay and how it is affected by climate change and hydroelectric power stations. I am interested in the interaction between atmosphere and climate and how it affects the biology. I am glad to be on the training cruise, because it gives me a better insight on current Climate predictions and changes and how we are taking action through ocean governance.
Daniel Gebregiorgis Yirgaw: I recently gained my PhD from Christian Albrechts Universität in Kiel. My PhD work examined the link between the South Asian Monsoon (SAM) climate and orbital insolation, and provided a working hypothesis with regard to the response of SAM to interhemispheric insolation changes. I am extremely pleased to have the opportunity to participate on the NOSAT, 2016 training expedition and gain practical knowledge in various interrelated disciplines of physical, chemical and biological oceanography as well as relevant fields of ocean governance and environmental law.