Christiansø & Bornholm
The Baltic is not famous for its diving. Really more of a brackish lake than a sea, this almost enclosed body of water supports a much lower diversity of marine life than the nearby marine waters of the North Sea and North Atlantic. Although the Baltic has been an important source of fish such as cod and herring for the people living on its shores, a diver is much more likely to encounter masses of algae and not much else. Consequently, we ordinarily do not include Undersea Specialist operations in our journeys here. Today, however, I made a dive at Christiansø, and things worked out very well indeed.
This was something of a special occasion as well. One reason I chose to dive at Christiansø was to take our new HDV underwater video rig for a shakedown cruise. This new piece of gear now allows us to use a much higher quality camera, the same that our video chroniclers use, underwater. When I planned the dive I chose Christiansø as the site because it is quite close to the mouth of the Baltic and I hoped to see more than “masses of algae”, but to be honest my expectations were not very high.
Entering the water, I submerged into a green world. Sure enough, there was algae, both filamentous and kelp, covering the rocky bottom and more microscopic phytoplankton tinting the waters all around me. But filamentous algae, colloquially known as slime, has been mentioned in a recent presentation by David Silverberg, our National Geographic Expert, so I took the opportunity to record it in the hopes that our guests would enjoy seeing slime in its native habitat. Filamentous algae play an important role as a nursery habitat in the Baltic, but easily grow out of control and contribute to eutrophication when excess nutrients such as fertilizer and sewage are present.
Descending a little more, I found masses of bay barnacles and zebra mussels covering the rocks and actively feeding from the green waters. Good! Another chance to illustrate a point made by several of my collegues: both these species are alien to the Baltic. Introduced species like these often out-compete native species and create problems by growing out of control. Nearby was a round goby, an alien fish species that just arrived in the Baltic in 1990.
Deeper still, along the fringes of the sandy bottom flat, I found several large timbers that showed signs of joinery indicating that they were used no more recently than the middle of the 19th Century, probably for small houses on shore. Once again this illustrated a point brought out in an earlier recap by Tom Ritchie. In any other sea these timbers would have long ago been consumed by toredo shipworms, but these animals cannot survive in the relatively fresh waters of the Baltic, allowing timbers like these and famous shipwrecks like the Vasa to survive for many centuries.
This opportunity to record scenes that illustrate and confirm what we have learned as travelers is exactly what I hope for as an undersea specialist. In the Baltic it was all the greater a pleasure for being unexpected.
The Baltic is not famous for its diving. Really more of a brackish lake than a sea, this almost enclosed body of water supports a much lower diversity of marine life than the nearby marine waters of the North Sea and North Atlantic. Although the Baltic has been an important source of fish such as cod and herring for the people living on its shores, a diver is much more likely to encounter masses of algae and not much else. Consequently, we ordinarily do not include Undersea Specialist operations in our journeys here. Today, however, I made a dive at Christiansø, and things worked out very well indeed.
This was something of a special occasion as well. One reason I chose to dive at Christiansø was to take our new HDV underwater video rig for a shakedown cruise. This new piece of gear now allows us to use a much higher quality camera, the same that our video chroniclers use, underwater. When I planned the dive I chose Christiansø as the site because it is quite close to the mouth of the Baltic and I hoped to see more than “masses of algae”, but to be honest my expectations were not very high.
Entering the water, I submerged into a green world. Sure enough, there was algae, both filamentous and kelp, covering the rocky bottom and more microscopic phytoplankton tinting the waters all around me. But filamentous algae, colloquially known as slime, has been mentioned in a recent presentation by David Silverberg, our National Geographic Expert, so I took the opportunity to record it in the hopes that our guests would enjoy seeing slime in its native habitat. Filamentous algae play an important role as a nursery habitat in the Baltic, but easily grow out of control and contribute to eutrophication when excess nutrients such as fertilizer and sewage are present.
Descending a little more, I found masses of bay barnacles and zebra mussels covering the rocks and actively feeding from the green waters. Good! Another chance to illustrate a point made by several of my collegues: both these species are alien to the Baltic. Introduced species like these often out-compete native species and create problems by growing out of control. Nearby was a round goby, an alien fish species that just arrived in the Baltic in 1990.
Deeper still, along the fringes of the sandy bottom flat, I found several large timbers that showed signs of joinery indicating that they were used no more recently than the middle of the 19th Century, probably for small houses on shore. Once again this illustrated a point brought out in an earlier recap by Tom Ritchie. In any other sea these timbers would have long ago been consumed by toredo shipworms, but these animals cannot survive in the relatively fresh waters of the Baltic, allowing timbers like these and famous shipwrecks like the Vasa to survive for many centuries.
This opportunity to record scenes that illustrate and confirm what we have learned as travelers is exactly what I hope for as an undersea specialist. In the Baltic it was all the greater a pleasure for being unexpected.
