The sea makes up 71% of the Earth’s area, and the biodiversity of marine ecosystems is far greater than in terrestrial ones. I got to experience this last week during an excursion to Frøya with the subject Marine Biodiversity, a 3rd year class for marine biology students at NTNU.
Monday morning, R/V Gunnerus, NTNU’s research vessel, took us to the small and beautiful island Frøya, west of the entrance to Trondheimsfjorden. We were 15 students, our lecturers Geir Johnsen and Torkild Bakken and the Gunnerus crew. The boat trip took around six hours, and on the way we harvested plankton; both zooplankton at 500 meters depth, and phytoplankton at the water surface. Already at this point, just looking at these small organisms, we noticed the big range in different kinds of species. Plankton comes in all shapes - some quite cool and interesting-looking - and sizes, from less than 20 micrometers to more than 2000.
Shagreen ray discovery!
On Tuesday it was time to take a look at bigger organisms, and we went trawling in Frohavet, a couple of hours outside of Frøya. Rosefish, rabbit fish, rock grenadier, velvet belly lanternshark, blackmouth catshark, witch flounder, greater forkbeard, blue whiting and angler were some of the fish species we identified. Other species included “Norway lobster”, brown crab, brittle stars, common sea stars, sea cucumbers, sea urchins, and many many more. Great fun and a bunch of excited students and teachers. In addition we made a very special discovery- a small shagreen ray, a species which is thought not to have been seen in Norway the past 100 years, got to be a passenger on Gunnerus for a couple of minutes (Photo top left by Geir Johnsen). Because of climate change, some species become more common in Norwegian waters, while others disappear. The shagreen ray had seemingly disappeared, so especially our teachers Geir and Torkild, the latter also works at the NTNU University Museum, were thrilled at the sighting. We quickly let our little friend back in the ocean, alive and well, as we would like it to spread its genes. You can read more about the shagreen ray on the NTNU University Museum blog here (in Norwegian).
Kelp forests- the tropical rainforests of the sea
Wednesday and Thursday were dedicated to kelp forests. We filmed with GoPros with a video rig from the boat, and handheld while freediving. We also collected species from the shoreline. Kelp forests are, together with coral reefs, the marine equivalent of tropical rain forests, both in terms of being important primary producers and making up habitats for numerous marine organisms. On one square kilometer of kelp forests, we can find more than 100 000 small invertebrates like snails and crustaceans of more than 200 different species. We were interested in discovering which species live in the kelp forests, and how the marine biodiversity is affected by factors such as depth, and hence light access and water temperature, and bottom conditions.
Thursday night was also the night of an event we had been looking forward to- seafood buffet with the catch from the trawl, made by us, the Gunnerus chef Mats and the rest of the crew. Forkbeard fish and chips, angler wrapped in bacon, marinated Norway lobster and rosefish, crab claws and crab cakes, thai soup with cod, and fried Palmaria palmata (red algae) were among the dishes. It was a great evening with amazing food from the sea, and a perfect end to a nice and educational trip.
The marine biodiversity course is definitely a course I recommend taking, especially if you have a special passion for the ocean and its inhabitants. It’s fun, interesting and social, and the excursion lets you be hands on and really develop an understanding of the vast biodiversity we find in our waters. Everything is connected- from the smallest plankton to the biggest shark- and dependent on the survival of one another. This definitely raises your awareness of the importance of conserving marine ecosystems. Sustainable management of the ocean is vital; both for the future of the environment and the ecosystems, and for the future of our own species.
Written by Ingrid Holtan Søbstad