- Algal bloom
- A massive reproduction event by algae and other
single-celled organisms in rivers, lakes or the ocean triggered by an increased input of nutrients. Algal blooms are a natural pheno-
menon. As a result of overfertilization, however, especially pronounced episodes occur today in many marine areas. When the algae die, they are broken down by bacteria, which consume oxygen. This produces “dead zones” in severely overfertilized waters.
- Changes in nature caused by humans, such as the increase of CO2 concentrations in the atmosphere, are referred to as anthropogenic.
- The gaseous shell that surrounds the Earth. Its major components are nitrogen and oxygen. The carbon dioxide content is only around 0.038 per cent. This gas, however, apart from water vapour, is the most important cause of the greenhouse effect.
- Azores High
- An atmospheric high-pressure area that regularly forms in the central North Atlantic near the latitude of the Azores. Cold air sinks here, is warmed by the Gulf Stream, and is transported eastward toward Europe.
- Ballast water
- Water that is pumped into special ballast water tanks in ships’ hulls for stabilization. Ballast water is transported over large distances, particularly by cargo vessels. Organisms in the water such as algae, larvae and bacteria can easily cross the oceans in this way. When they become established in a new habitat they can displace native species.
- The biological variety of the Earth. This includes not only the species as such, but also the genetic variability present within the individuals of a species, or the variability of habitats in a region.
- Substances produced by living organisms such as plants, animals, fungi or bacteria are referred to as biogenic.
- Biogeochemistry is an interdisciplinary scientific field that encompasses chemical, biological and physical processes and their interactions. Many processes in nature can only be understood when all three of these aspects are taken into account. One accordingly refers to biogeochemical phenomena or processes.
- The part of the Earth’s crust inhabited by living organisms. The biosphere also includes the ocean.
- Carbon cycle
- The cycle of the chemical element carbon. It includes the transformation of carbon chemical compounds within the global lithosphere, hydrosphere, atmosphere, and biosphere systems, as well as the exchange of carbon compounds between these systems. The carbon compounds can be in the form of gas (in the atmosphere), or bound up in solid material, for example, in water-soluble carbonate or in the solid biomass of plants in the form of carbohydrates.
- Carrying capacity
- The maximum number of individuals or species that can exist in a habitat. It is determined in part by the amount of available food and, in the case of fish, by the available spawning sites.
- The portion of the Earth covered by ice. The cryosphere includes antarctic glaciers, mountain glaciers, sea ice and shelf ice.
- CO2 Carbon Credits
- CO2 Carbon Credits allow industrial enterprises worldwide to emit a certain amount of CO2. If a company reduces its CO2 emissions through technical measures, it uses fewer of its Carbon Credits, and can sell them to other companies. Measures designed to reduce CO2 output thus become more attractive economically despite the initial additional cost they entail.
- In the context of the ocean or atmosphere, convection refers to vertical turbulent motion of the water or air, usually caused by density changes (for example,due to cooling or warming). Convection in the ocean plays a primary role in driving the thermohaline circulation.
- Convention on Biological Diversity (CBD)
- The Convention on Biological Diversity (CBD) was negotiated in 1992 in Rio de Janeiro, during the United Nations Conference on Environment and Development (UNCED). It pursued three primary goals: 1. conservation of biological diversity, 2. sustainable use of natural resources, and 3. assurance that the utilization of genetic resources and information (for example, for medically useful substances) is equally beneficial for all countries.
- Coriolis force
- The coriolis force or coriolis acceleration, caused by the Earth’s rotation, causes freely moving masses such as air and water currents to be diverted from straight linear motion. In the northern hemisphere, the coriolis force deflects linear flow to the right, in the southern hemisphere to the left, and at the equator there is no effect.
- Single-celled, hard-shelled algae with a carapace of silica. Most diatoms in the ocean are a component of the plankton, and they are among the most important producers of oxygen in the ocean. They are also an important nutrient base for higher organisms. Diatoms also occur in freshwater and on the sea floor.
- East Pacific Rise
- A mid-ocean ridge located in the southeast Pacific.
- El Niño
- An irregular climate phenomenon occurring every 3 to 8 years in the Pacific Ocean between Indonesia and Peru. The direction of the trade winds and ocean currents reverses due to atmospheric pressure changes. Off the coast of Peru this leads to a decline in the upwelling of cold, nutrient-rich water from the deeper layers to the surface. El Niño is Spanish for infant Jesus. The phenomenon was so named because it often occurs around Christmas time.
- Plant and animal species that only occur in a particular and limited area of the world are called endemic. Endemic species are very susceptible to extinction due to degradation of their habitat.
- single-celled organisms that move through the water using a whip-like appendage called the flagellum. They are found in both freshwater and saltwater.
- technical measures that could influence the natural cycles on a grand scale, applied to counteract the impacts of climate change. These measures are broadly divided into two groups: Solar Radiation Management (SRM), and Carbon Dioxide Removal (CDR). SRM deals with the release of certain substances into the atmosphere to influence incoming solar radiation, while CDR generally refers to the large-scale breakdown or storage of CO2. The techniques are controversial because they severely intervene with natural processes, and because their direct consequences and side effects, as well as possible reciprocal impacts, are difficult to predict.
- Greenhouse effect
- Water vapour, carbon dioxide (CO2) and other climate-relevant trace gases in the atmosphere, including methane (CH4), initially allow short-wave radiation from the sun to pass through to the Earth. At the Earth’s surface these are transformed, and reflected back for the most part as long-wave radiation. Like the glass panes in a greenhouse, however, the gases then prevent the long-wave heat rays from escaping into space. The Earth warms up. The greenhouse effect is a natural phenomenon that protects the Earth from overcooling. With increasing concentrations of CO2 and other trace gases, however, the greenhouse effect is intensifying.
- Greenland Sea
- The Greenland Sea extends from Greenland to Iceland and Spitzbergen, thus forming the boundary between the North Atlantic and Arctic Oceans. Large water masses sink to greater depths in the Greenland sea due to convection.
- Gulf Stream
- a relatively fast, warm ocean current in the Atlantic. The Gulf Stream flows out from the Gulf of Mexico, around the Florida peninsula toward the northeast, and into the North Atlantic Current. It contributes significantly to the relatively mild climate in western Europe because it transports large amounts of heat.
- a characteristic natural environment inhabited by a particular species.
- Icelandic Low
- a semi-permanent, low-pressure area over the North Atlantic. A large proportion of the precipitation in western Europe is transported in by this low. Interplay between the Icelandic Low and the Azores High is a significant factor in determining the weather in western Europe.
- Interhemispheric dipole
- A regular fluctuation of water temperatures in the Atlantic, occurring about every ten years. Scientists refer to this as a temperature anomaly.
- International Whaling Commission (IWC)
- The International Whaling Commission (IWC) provides information annually on the status quo of the worldwide whale stocks, the establishment of protection areas, and on extensions of the whaling moratorium. It was established by the International Convention for the Regulation of Whaling (ICRW). This convention is an agreement created under international law whose aim is the preservation and management of whale stocks. The IWC comprises representatives from around 80 signatory nations.
- Labrador Sea
- The area of the North Atlantic between Greenland and Canada. As in the Greenland Sea, large water masses sink to greater depths here due to convection.
- the solid rock shell of the Earth.
- Mean sea level (NN)
- Mean sea level (German – Normalnull, NN) is a reference point for standardizing measures of elevation in Germany, Switzerland and Austria. It is equal to the average elevation of sea level. This point is also used as the reference when specifying the elevation of buildings or mountains. It was originally derived from the Dutch usage of the Normal Amsterdam Level (NAP – Normaal Amsterdams Peil) standard since the 19th century, which referred to the average water level in the Zuidersee, known today as the IJsselmeer.
- Mid-ocean ridge
- Ridges or mountain ranges on the sea floor similar to the seams of a baseball, extending around the entire globe. They originate in areas where continental plates drift apart beneath the ocean. Hot magma rises at these fracture zones in the central ocean regions, is cooled in the water, and piles up through time to form enormous mountains.
- Monsoon (region)
- A large-scale, strong and constant air current in the tropics and subtropics. The monsoon changes direction twice a year. This is caused by annual changes in the altitude of the sun. When the sun is high, the amounts of heat assimilated by the land and water masses are very different, which leads to distinct air-pressure differences and strong winds. When the monsoon blows from the sea it brings humid air masses and causes strong monsoon rains. This sometimes results in large floods.
- Multispecies fishery
- Fishing for multiple species of fish at the same time. Whether a fisherman catches a number of different species in his net depends on several factors, including the behaviour of the fish, the marine area, and the time of year in the case of mi-
grating fish. In multispecies fishing, species are often caught that are of no interest to the fisherman, or that he is not allowed to sell. These fish are usually thrown overboard dead.
- Civil-society interest group that attempts to influence policies. NGOs counterbalance the representation of governmental interests. NGOs are especially active on issues relating to social equity and environmental quality.
- North Atlantic oscillation (NAO)
- Refers to the fluctuation of the pressure relationship between the Azores High and the Icelandic Low. The NAO is especially important in driving the winter climate in Europe, but also in North Africa, Greenland and the eastern USA. Researchers believe that the NAO determines 30 per cent of the European winter weather. The NAO also exists during the summer, but during this time it seems to be less critical for climate. A systematic change in this air-pressure system has been observed in recent years compared to earlier measurements. One result has been an increase in warm winters in Europe with less snowfall.
Fluctuations in the atmos-pheric pressure difference between the Azores high and Icelandic low. The NAO is especially influential in determining the winter climate in Europe, but also has an effect on North Africa, Greenland and the eastern USA. The aspects of its influence include water temperatures in the North Atlantic.
- Oceanic ridge
- Ridges or mountain ranges on the sea floor that form where continental plates drift apart. At these plate boundaries, magma rises from the Earth’s interior, is cooled by the water, and over time forms enormous mountains.
- The input of unnaturally large amounts of nutrients from agriculture or from industrial or municipal effluent into natural waters. Overfertilization leads to increased reproduction of algae, called algal blooms. The problematic substances include nitrogen and phosphorus compounds from mineral fertilizers of from faeces and urine.
- The pedosphere is the part of the continental land masses that is referred to as soil. It is the interface between the atmosphere and the lithosphere. The pedosphere is a layer of loose, small grained rock material that is enriched in organic substance and usually contains some amounts of water and air.
- Organisms that live and feed in open waters are called pelagic.
- Pelagic system (pelagial)
- The term pelagic system is used to indicate the main body of the open water (pelagial) including all of its inhabitants. Pelagic organisms comprise the plankton and the nekton. The nekton includes organisms such as fishes and whales, which, in contrast to the plankton, are able to actively swim against the currents.
- Permafrost ground
- Ground that is permanently frozen, year-round, below a particular depth. Among other areas, permafrost grounds are found in the arctic tundra, in northern evergreen forests, and in the high mountains. In these regions the sun’s energy is not sufficient, even in summer, to warm the ground to depth. Only the upper layers thaw out for a few weeks.
- Organisms that feed on plankton (microalgae, fish and mussel larvae or krill) are called planktivores.
- All free-floating organisms in the open water. Most planktonic organisms are microscopic in size. They include protozoans, microalgae, krill, and the larvae of fish and mussels. A distinction is made between plant plankton (phytoplankton) and animal plankton (zooplankton). Planktonic organisms are able to propel themselves, but only very weakly, so they are forced to drift with the water currents. In contrast to the plankton, the nekton includes all marine animals that can actively swim independently of the currents.
- A group of individuals of one species that inhabit the same area at the same time. A population forms a reproductive community. One species can develop multiple populations at different locations.
- Primary production, primary producers
- The production of biomass by plants or bacteria. The primary producers obtain their energy from sunlight or from certain chemical compounds, and through their metabolism synthesize energy-rich substances such as carbohydrates. These substances, in turn, represent a subsistence basis for animals and humans.
- Red List
- Plant and animal species as well as habitat types are classified into several categories in red lists according to the degree of threat, for example, from “near threatened” to “extinct”. The most important worldwide Red List is issued by the International Union for Conservation of Nature (IUCN). Individual countries or regions also have their own lists that are released by various public authorities. For the Baltic Sea, for example, there is the Helsinki Commis-sion, HELCOM. The classifications can differ from list to list. On the IUCN List, for example, the small-spotted catshark is classified as “least concern”, because it still has a wide distribution. In the Baltic Sea region, however, it is now very rare and is therefore classified as “endangered” in the HELCOM List.
- Shelf area
- the near-coastal, shallow part of the sea floor. The shelf falls gradually to an average depth of 130 m. The shelf ends at the continental slope.
- a natural reservoir that can hold large amounts of a given substance, such as carbon dioxide. For example, carbon sinks include forests, the deep ocean, and even corals, because of the carbon dioxide bound up in the carbonate.
- Stratospheric, stratosphere
- The stratosphere is that area of the atmosphere that lies at an altitude between around 15 and 50 kilometres. Within the stratosphere at around 20 to 40 kilometres there is a band with higher ozone concentrations. This „ozone layer“ blocks a large portion of the ultraviolet solar radiation that can be harmful for living organisms.
- the material that an organism lives upon, for example, stones to which barnacles are attached.
- a subdiscipline of physics that deals with the relationships between heat and other forms of energy, as well as their possible transformations. Important parameters include pressure, temperature and mechanical work, as well as changes in volume, density and physical state, which also play a role in the origins of currents in the ocean and atmosphere.
Thermohaline circulation: a global system of near-surface and deeper ocean currents that is driven by density differences between water masses with different salinities and temperatures. Convection is an important motor for thermohaline circulation.
- Tidal zone
- the area of the coasts defined by the limits of high and low tide. The water level falls and rises here in phase with the tides. This creates some areas that are periodically not covered by water. Characteristic biotic communities often colonize these areas.
- Trade winds
- winds that constantly blow in the tropics and are thus a driving force for the ocean currents. The trade winds occur up to around 23 degrees latitude north and south of the equator. In the northern hemisphere they are called the northeast trades, and in the southern hemisphere the southeast trades. The direction of the trade winds is primarily determined by the diverting effect of the coriolis force.
Trade winds (trades): Winds that blow consistently in the tropics and are thus a driving force for ocean currents. The trade winds are located between approximately 23 degrees north and south of the equator. The northeasterly trades in the Northern Hemisphere are distinguished from the southeasterly trades in the Southern Hemisphere.
- United Nations Conference on the Law of the Sea
- Between 1973 and 1982, three United Nations Conferences on the Law of the Sea (UNCLOS) were held with the aim of establishing internationally enforceable maritime law. This was accomplished with the third Convention (UNCLOS III) in 1982. The result was the adoption of the UN Convention on the Law of the Sea. So far the Convention has been ratified by 157 nations.
United Nations Convention on the Law of the Sea (UNCLOS): UNCLOS has defined the rights of nations with respect to the sea since 1982. For this purpose it divides the seas into various zones. For example, under UNCLOS every nation-state has the right to manage the fish stocks in its Exclusive Economic Zone (EEZ), which extends to a distance of 200 sea miles from its coast. Beyond the EEZ, the high seas freedoms apply under UNCLOS. Fish may be caught here by any country. In addition, UNCLOS regulates shipping, marine environmental protection, and the production of oil, gas and other resources in the ocean. UNCLOS is the legal foundation for the International Tribunal for the Law of the Sea.
- Upwelling region
- usually near-coastal marine regions where cold, nutrient-rich deep waters rise to the ocean surface. The motion is commonly driven by trade winds blowing parallel to the shoreline. The winds force the surface water away from the coasts and deeper water rises to replace it. Biologically, upwelling regions are highly productive, and are thus very important for fisheries, which are often concentrated at the western margins of continents, particularly off the coasts of Chile, California and Namibia.