Seabirds are such a common feature of any visit to Scotland’s beautiful coast that we become blasé about them. Yet they are one of our national specialities.

Scotland is home to some 70% of all of the seabirds in the UK and the UK is home to almost a third of all of the seabirds in the European Union. For species such as the Great Skua, the Atlantic Puffin and the Northern Gannet, we hold the bulk of the world population.

The gannet’s plunge into the unfamiliar twilight of the marine environment reminds us that, though they may need rocks to nest on, they depend on the sea for their sustenance, and that the extraordinary richness Scotland’s bird colonies reflects the productivity of the surrounding seas. Seabirds are only the visible tip of the iceberg of the vast marine ecosystem.

Marine life is strongly influenced by ocean currents, which bring nutrients to refresh the surface waters exhausted by the continual effort of rearing crops of floating algae. The North-east Atlantic plays a key role in the global pattern of ocean circulation, at the pinch point where the northward-flowing North Atlantic Drift is replaced at depth by cold waters pouring out of the Arctic basin. For this reason it is one of the world’s most productive seas, sustaining a teeming broth of algae, invertebrates, fish, marine mammals and ultimately seabirds.

While, on land, climate change is measured in tenths of a degree, the sea surface temperature in the southern North Sea has risen by some 2C in the last 20 years. This has had a dramatic effect on the timing of appearance of the different species plankton, a complex choreography formerly perfectly timed to provide the food needed for the seabirds’ breeding seasons. There is increasing evidence that the alarming breeding failures of seabirds in Shetland and Orkney in 2003 and 2004 are the first signs of our impact on the world’s climate.