64PE374 - Dagboek 3 (in het Engels)

After eating some tasty yapral sarma and a doner kebab in a busy place in the Asian side of Istanbul, I was ready to embark on an exciting trans-Med cruise aboard R/V Pelagia. This is Leg 3 that will take us to Lisbon crossing the Aegean, Adriatic, Ionian, Tyrrhenian and Alboran Sea and finally back to the open ocean.

I am a geochemist from the Institute of Marine Science (ISMAR) in Bologna and I am mainly interested in the chemical composition of corals (especially cold-water corals) for paleoclimate research. So why am I on board this GEOTRACES cruise since we are not hunting for corals?? Well, part of the GEOTRACES project is dedicated to “proxy development for past change” and this is a unique opportunity for me to compare the neodymium isotopic composition of the seawater to the geochemical composition of frame-building or solitary cold-water corals that were collected over the last 8-10 years along the Mediterranean Sea, some being very close to the stations that I planned to sample. At the same time this cruise offers the chance to better characterize the different water masses flowing in the Med Sea in terms of their neodymium isotopic composition.

Paolo Montagna

Neodymium isotopes (143Nd/144Nd or Nd) can be effectively used to trace provenance and water mass mixing since different water masses have different Nd isotopic compositions. The seawater ultimately derives its 143Nd/144Nd ratio through continental weathering, erosion and particle-seawater interactions. The landmasses bordering the Mediterranean Sea have a distinct Nd isotopic composition and this makes it possible to distinguish between different regional inputs. Generally speaking, the water masses in the Western Mediterranean Sea have lower Nd values, a fingerprint of the Atlantic water entering the Med Sea through the Strait of Gibraltar, whereas the Eastern basin displays more radiogenic values reflecting the contribution of partially dissolved Nile River particles. As seawater 143Nd/144Nd can be preserved in dispersed authigenic ferromanganese oxide fraction in marine sediments, foraminiferal shells, fossil teeth and coral skeletons, Nd isotopes can be used to reconstruct the water circulation in the past.

We’ve just passed through the Strait of Messina that divides the beautiful island of Sicily from the continent, a narrow passage where the nymph Scylla was transformed into a monster with four eyes and tentacle-like legs. Using her sharp teeth she was attacking the ships that attempted to cross the Strait, becoming the nightmare for many sailors obliged to pass close to the other side.

Strait Messina

Nothing happened to us, we safely passed the Strait of Messina and Scylla was probably still sleeping. We were tempted to call and ask for a tray of “cannoli siciliani”, one of the typical Sicilian pastry dessert, a little tube of fried dough filled with fresh ricotta!!! We did not eat cannoli but Rik, our chef on board, delighted us with a chocolate cake and some tasty “zeeuwse bolussen” to celebrate Martijn’s birthday.

Paolo Montagna