NIOZ Science Plan 2008-2012
NIOZ-Research comprises 5 monodisciplinary departments at Texel and 4 thematically organised working groups in Yerseke, which collaborate on the 5 multidisciplinary themes as presented in our NIOZ Science Plan 2008-2012:
Theme 1. Open Ocean Processes
The open ocean ecosystem: how does it work?
The global thermohaline circulation connects the world's oceans with each other and the sea surface with the deep sea. Vertically, the water column can be divided into a thin surface layer of about 100 m where sunlight can penetrate, and a thick eternally dark layer underneath reaching to the sea-bottom typically at 3-6 km depth. Single-cell algae form the basis of the ecosystem in the sea-surface layer. Growing algae use carbon dioxide to build their cells, using energy from sunlight (photosynthesis). Inorganic nutrients (nitrate, ammonia, phosphate) fuel this process. In certain areas of the open ocean, iron is the growth-limiting nutrient. Dead cells of algae and zooplankton slowly sink to the deep sea, where they are again degraded into the basic building blocks by micro-organisms, consisting of Bacteria and Archaea. Upwelling currents render these elements available for a new cycle of life at the sea surface.
Theme 2. Sea Floor Dynamics
How do physical, biological, chemical, and geological processes result in the formation of marine sediments?
The particles on the sea floor are either eroded from the continents or are remnants of marine organisms. The initial formation of sediments due to the settling of these particles is controlled by the interaction of water currents with the sea floor. Sea floor highs and lows may severely affect the patterns of sediment deposition and erosion. Submarine canyons incising the continental margin may act as highways for sediment transport from river outflows directly to the ocean floor. Cold water coral reefs extend several hundred metres above the sea floor at water depths of 40-2000 m. These mounds interact with the water flow, invoking transport of food particles to the reefs. During transport and deposition, these particles are transformed by micro-organisms, changing the chemistry of the sediment and water column. Other ecosystems on the sea floor live on material from the inner part of the earth emerging from the sea floor. Bacteria instead of algae form the basis of such food webs.
Theme 3. Wadden and Shelf Sea Systems
How can our coastal systems develop in a sustainable way?
The Wadden Sea and North Sea are both regarded as highly valuable marine areas on a global scale. Large benthic animals form the core of their ecosystems. They serve as food for migratory birds, for which theWadden Sea is an indispensable refueling-station on their flights between Africa and Polar Regions. The Wadden Sea also serves as a nursery for fish. During the last decade, the number of harbourporpoises along the Dutch coast has been steadily increasing, but is this a good sign or an illustration of extreme poverty in the northern North Sea? Intensive human usage has led to a sharp decrease in quality during the last decades. An integrated multi-disciplinary knowledge from water currents to the ecology of top-predators is necessary to take measures to improve the system. Modelling and long-term monitoring series are essential tools to achieve this goal.
Theme 4. Climate variability and the Sea
What will change in our seas and oceans?
During glacial periods the North Sea was part of the European continent. Other periods have been really hot; 55 million years ago theArctic Sea was about as warm as our modern North Sea (TEX86 index). Thus the current problem is not so much the high temperature itself but more the extremely rapid rise in temperature. Global warming causes a shift of climate zones from the Equator towards the Poles. Possibly, the large ocean currents may also change. In Europe, especially the winters will become warmer, allowing shrimps to migrate from the North Sea to the shallow Wadden Sea earlier in spring. There they will eat the swimming larvae of benthic animals. This severely hampers the reproduction of shellfish species. The increase of carbon dioxide will lead to the acidification of the sea and the dissolution of carbonate at the sea floor. Shellfish and corals may experience difficulties forming their hard calcareous parts in the future.
Theme 5. Biodiversity and Ecosystem Functioning
What is the role of species in ecosystems?
Ecosystems may contain many or only a few species. Biodiversity is often high in tropical regions, but the North Sea also contains some species-rich areas, such as the "Frisian Front". Is a species-rich ecosystem more, or less, productive than a system with only a few species? In one litre of sea water we often find about ten types of very abundant bacteria but about 10,000 extremely rare types. Will they become abundant if the circumstances change, and does that matter for ecosystem functioning? Some key species form large physical structures, such as coral reefs, mussel beds and sea grass meadows. Does this enhance biodiversity? Invasions of species caused by human activities occur more and more frequently. Intercontinental exchange of marine organisms through ballast water transport by ships and imports for aquaculture diminish regional differences in species distribution.
Climate variability and the Sea