Jun05

Perfect for Plankton

Categories // North Sea Wildlife Officer

Perfect for Plankton

Wildlife can most certainly be seen as the productive North Sea feeds the cetacean wildlife

If I had a pound for every time someone asked me ‘but can you really see any wildlife here?’, I’d have a pretty big donation tucked away for Orca by now! There is lots of wildlife in the North Sea and with a little patience and luck you can spot all kinds of things. Taking an hour out of your journey on a ferry like the DFDS King Seaways to stand on deck might be the best decision of your whole trip – many people see dolphins or whales for the first time in their lives just a few miles away from the coast of the UK!

The North Sea has a reputation for being cold and rough and full of oil rigs and fishing vessels, but all of these things are actually a dead giveaway for the fact that this place is (or could be) incredibly rich in interesting and varied plants and animals.

Located quite far north and just under the Arctic Sea it is cold here, many animals are adapted to, and need, cold water to survive. Phytoplankton, the tiny plants that are the foundation on which the rest the marine food web is built, has been shown to grow better in cooler waters. Not only that but the further north you go, the longer the summer days are. Lots of summer sun means the phytoplankton has more of the sunlight it needs to grow.

And yes, there are many, many oil platforms and wind turbines. That is largely due to the fact that the North Sea is very shallow and so they can be more easily installed than in some deeper oceans. However, being shallow is again important for plant growth. With sunlight unable to penetrate water as easily as air, after a depth of about 200m very little sunlight gets through. The North Sea has an average depth of just 90m (and if you exclude the deep trenches around Norway the average is much shallower) and so the phytoplankton and other plants right from the surface to the sea floor can receive the benefit of all that summer sun.

And finally, yes, it can be quite rough and windy here. But in a shallow sea the ‘bad’ weather means that the waters get well mixed. In many deep seas we have sunlight at the top of the water and the nutrients that plants need (mostly from dead animals and feces) tends to sink. If floating plants like phytoplankton are to thrive they need both. With the North Sea’s high winds pushing water down, it creates strong currents that push deeper waters, containing the sunken nutrients, back to the surface. This mixing also helps to maintain a relatively constant temperature through the water depths, again providing ideal plant growing conditions throughout.

So we have the perfect situation for phytoplankton to grow and provide food for zooplankton. If we have a large amount of plankton, we have the base for life. And, actually, we already know that there is a lot of life here because we all know that the North Sea is a major fishing ground. The reason this area has historically been so great for fishing is simply because there are a lot of fish!  And if there are a lot of fish, there are bound to be animals that eat them. Grey seals, white beaked dolphins, harbour porpoise and bottlenose are all spotted frequently on board the King Seaways during summer when food is abundant, not to mention the thousands of seabirds from terns and auks to gannets and gulls.

Unfortunately, as bad fishing practice continues to haunt our North Sea we are seeing the numbers of fish at shockingly low numbers. Protecting our cetacean species can only work if we also protect their food and their space. Here on the King, not only are we spreading the message of marine conservation, but in our daily surveys we are looking for the most important areas to cetaceans in the Southern North Sea. With this data we can push for better legislation and bigger protected areas so that cetaceans can continue to be a part of life here in the North Sea. 

Rose

ORCA Wildlife Officer - North Sea 

King Seaways Presentation