Our seas are home to a fascinating range of biological diversity. There are incredibly varied life-forms. The diversity of species is hard to believe.

From coastal waters to the deep seas, there are spectacular, ecologically important habitats.

Protecting this diversity of marine life for the future is a major challenge. Creating marine protected areas (MPAs) is one way of meeting that challenge.

In the North-East Atlantic, the countries that have signed the Paris-Oslo Convention, OSPAR, share responsibility for MPAs in international waters. In national waters, MPAs are the responsibility of each state. Large areas of coastal waters in the German Bight are strictly protected as national parks.

The reefs and the unique kelp forests around Heligoland are protected with their characteristic fauna and flora. Together with the three German MPAs beyond the 12-mile limit, and with 43 percent of the German North Sea in total, they form part of Natura 2000 - a network of protected areas for threatend species and habitats across Europe.

But the seas are anything but untouched nature. Instead, they are host to ever-increasing economic activity.

There are risks and dangers from shipwrecks, maintenance work, noise, and physical disturbance to the sea floor. This is just the same in the high seas as it is in coastal waters.

Impacts like these are also a fear for MPAs like the Sylt Outer Reef. Many endangered species live on the reefs there and on the sands of the Amrum Bank, a rearing ground for various kinds of fish. These provide sufficient food for harbour porpoises with their young, and for seabirds.

The biggest sandbank in the North Sea is Dogger Bank, which is exceptionally rich in fish species. The Natura 2000 MPAs set up here by three different countries are visited by a whole selection of whale species and even the basking shark, a plankton eater, in the quest for food. These impressive sharks migrate along largely unknown routes through the North Sea, and evidently through the Channel to the south-west coast of England.

Other migrating species, too, like sperm whale and dolphins, need wide-ranging protection along their migratory corridors and in favoured breeding and feeding areas such as around the Azores.

The Azores are an archipelago on the Mid-Atlantic Ridge, a highly active volcanic zone.

Hydrothermal vents and gas seeps are found here, many hundred metres down. They are home to very special ecological communities with countless rare deep-sea species. Stony corals like Lophelia and Madrepora, together with gorgonians, form unique cold-water coral reefs.

Deep-sea mussels directly colonise the hydrothermal vents. They are specialists in this extreme environment, as are deepwater crabs. Portugal has put several of these valuable areas under protected status. But many unusual deep-sea habitats are outside any national jurisdiction. Intensive global efforts are underway to identify and assess these areas of outstanding ecological value. Part of this work is GOBI, a project with BfN funding:

Prof. David Johnson, Coordinator of the Global Oceans Biodiversity Initiative GOBI:

GOBI is a collection of partners, of organisations around the world, who are working on collecting information on biodiversity. So it's providing physical and biological data to organisations like the Convention on Biological Diversity that are keen to protect biodiversity and initiate marine protected areas but also these ecologically or biologically significant areas. So GOBI partners have been instrumental in the regional workshops to provide data as well as advice and expertise to stakeparties and to organisations that might bring together such protective areas. I think it's been a fundamentally important role the BfN in Germany has played to provide some funding that helps collecting this information.

Assessing and designating 'EBSAs' - ecologically or biologically significant areas - across the various marine regions is a complex process involving regional workshops all over the world. Some 200 EBSAs have been identified so far. Their final designation is decided on by the parties to the Convention on Biological Diversity.

Stephan Lutter, Worldwide Fund for Nature, WWF:

Identifying EBSAs, so called ecologically and biologically significant areas in the world oceans, is important especially in region outside OSPAR where we do not have governmental, inter-governmental framework for MPAs on the high seas and in the remote areas at sea. So, they serve as kind of precursors for MPAs, potential MPAs for the future and we as an NGO propose EBSAs also in the OSPAR maritime area where we see there is a gap.

But EBSAs are just the first step. Turning them into globally respected protected areas, most of all in marine regions outside of national jurisdiction, !!! takes good international cooperation. Germany's Federal Agency for Nature Conservation is involved in many of the bodies set up to designate MPAs.

A leading example is the Charlie Gibbs MPA, in a fracture zone on the Mid-Atlantic Ridge. With support from BfN and originally initiated by the WWF, scientists have identified exceptionally valuable areas within this zone.

More than 40 species of cold-water coral, including Lophelia, Madrepora and Gorgon's head are found here at depths between 700 and 4,500 metres. Likewise some 80 species of cephalopods, like the deepwater 'Dumbo' octopuses.

The OSPAR states agreed to designate an area of 324,000 square kilometres. The MPA is home to fascinating ecological communities. There are dozens of fish species, including 40 species of deepwater shark alone - like this kitefin shark.

The goal is to build a network of representative and well-managed MPAs across the whole of the OSPAR area. About 5.2 percent of the North-East Atlantic is protected so far. But there are still gaps - for example in Arctic waters.

While there are coastal protected areas, there is no widespread protection for areas far offshore. This makes effective management hard to implement and monitor. Yet these areas, too, are home to endangered species that have adapted to conditions in the icy waters, together with ecologically outstanding and highly sensitive habitats.

Even these remote areas are exposed to human pressures. Plastic waste and parts of old nets are a major threat to the marine food web. The debris of our civilisation is found from the Mediterranean to the Arctic Ocean.

But it is modern fishing practices that do some of the greatest harm. The expansion of fishing grounds across the high seas poses huge risks.

For decades, high-intensity, harmful trawling methods in various sectors of the fishing industry meant many stocks were overfished, damaging whole ecological communities.

In Europe, the reform of the Common Fisheries Policy now creates a new chance for fish stocks and marine ecosystems to recover.

From the Atlantic, we travel along the deep trenches past the Norwegian Coast, heading south.

Shoaling fish like herring and saithe are at home here. Another, somewhat scary-looking inhabitant is the monkfish - a sought-after but endangered table fish.

Cephalopods like red octopus find places to hide between the rocks. Sea-pens are characteristic of a special, rare type of habitat.

Sea anemones and rare cold-water corals like Paramuricea, a deepwater fan coral, grow along the Norwegian continental shelf.

Chimaeras flit through the deep dark waters. Marine protected areas once again play an important part in conserving these fascinating species and the whole ecosystem.

On we go, through the Skagerrak and Kattegat, to the Danish straits, the only place where there is an exchange of water between the North Sea and the Baltic. All the surrounding states have created MPAs here.

Despite these, nutrient and other forms of pollution from diffuse sources is still a widespread problem:

Lena Tingström, Swedish Agency for Marine and Water Management:

And of course, the eutrophication situation in the Baltic Sea is a big issue for us to address and that's not possible really within the separate Marine Protected Areas, so you have to work on broad scale like the Baltic Sea Action Plan.

The Baltic Sea is a highly sensitive ecosystem. Improving its overall ecological status and sustainable management of the sea is the goal of the parties to the Helsinki Convention, under the Baltic Sea Action Plan. The network of Baltic marine protected areas already takes in some ten percent of the sea. This includes five large areas in the German Exclusive Economic Zone, or EEZ.

Blue mussels, red algae and kelps are characteristic of the Fehmarn Belt and the Kadet Trench. Sea squirts are also found here. Further east, on the Odra Bank, highly endangered eastern Baltic harbour porpoise find a retreat.

Long-tailed ducks and many other seabirds spend the winter here in internationally significant numbers. For the protected areas in the German EEZ, the BfN develops management plans and works continuously to improve the protection rules. The outcomes, including rules on fishing in protected areas, are shared with other HELCOM and OSPAR party states to serve as examples in their own work - for example in the OSPAR Working Group on Marine Protected Areas, which is chaired by Germany through the BfN. But there is still much to be done before valuable marine areas can enjoy protection worldwide.

Prof. Henning von Nordheim, German Federal Agency for Nature Conservation, Marine Conservation Unit:

The first key step will be to finalize the EBSA process that CBD has started. That means, other parts of the world, which have not yet identified their ecologically important areas should do so as quick as possible. I'm talking about the Antarctica, for example, but also in the Arctic and other parts there are some pieces missing in this overall assessment.

The second and even more key step would then be to identify within those ecologically important areas those sites that should be granted an international conservation status, a protection status.

And to grant such a status we need a third step to be fulfilled and that is a global agreement on UN or on the level of UNCLOS that allows us to protect and conserve and restore areas in the international waters of the world where apparently we don't have an existing comprehensive instrument available.

So far, only 2.8 percent of the oceans are protected in line with the criteria of the Convention on Biological Diversity. The target is for 10 percent of the world's seas to be protected by 2020.

Marine species and habitats, from the coasts to the black smokers of the deep seas, seem inconceivably diverse. It is up to us to look after these treasures. Marine protected areas are a vital part of this. Managing them well and effectively is and remains a great challenge.