# Oceanography

Oceanography describes the marine sciences in all their breadth. In the English-speaking world, the terms marine science but also oceanography correspond to this meaning , while in German the term oceanography traditionally only includes physical oceanography . The part of oceanography that is specifically devoted to biological phenomena is called biological oceanography or marine biology in German .

Based on the term limnology for inland water science, the term “oceanology” ( Greek for marine science ) was coined temporarily in German in the sense of an analogy , but this has not caught on in specialist science.

Jacques-Yves Cousteau , one of the most famous oceanographers

## Areas of oceanography

Oceanography can be subdivided into several, albeit partially overlapping, sub-areas that differ in terms of content, methods and issues:

• Oceanography or physical oceanography: deals with physical processes in and on the seas . She researches parameters such as ocean currents , heat content of the oceans from temperature, salinity , speed of sound, oceanic acoustics , suspended matter or light permeability. In addition to currents, other movement processes such as turbulence, waves ( swell ), tides (ebb / flow ), wind and density-driven drift currents and the associated heat transport in the ocean are examined. The measurements required can
• Biological marine science or marine biology : examines biological peculiarities (e.g. adaptations in morphology, physiology and biochemistry of living things), occurrence, growth, reproduction and death rate of marine organisms and analyzes the ecological impact of environmental parameters, especially water temperature, salinity and currents. It is often divided into marine botany, marine zoology, planktonology, fishery biology, marine microbiology, and marine ecology.
• Marine ecology : Here, the ecological interactions between organisms and their environment are examined, as well as the effects of organisms on turbidity, sedimentation, nutrient cycles and sedimentation processes. Marine biology and marine ecology merge.
• Marine geology : researches processes thatshapethe ocean floor - past, present and future. The geological investigation of the deposits ( sediments ) provides information about the climate of the earth's history ( paleoclimatology ). Marine raw material deposits, for example in the form of mineral ores, gas hydrates or hydrocarbons, are also examined.
• Maritime meteorology and climatology : researches the interaction of the ocean with the atmosphere (e.g. heat, impulse and fresh water transport), the influence of the oceans on the climate system or the effects of weather phenomena such as cyclones, monsoons etc. on the seas.
• Maritime geochemistry : examines the interactions between chemical and geological processes in the sea and the chemical processes in the deposits ( sediments ).
• Marine biogeochemistry : examines the material cycle of the elements in the oceans and the microorganisms involved
• Chemical Oceanography: studies the origin and composition of seawater and chemical cycles of nutrients such as carbon or nitrogen .
• Marine engineering : development of technologies for sampling, observation and automatic measurement. Examples: Autonomous deep drifters, gliders , landers (deep seaobservatories), autonomous underwater vehicles ( AUV = Autonomous Underwater Vehicle), remote-controlled underwater vehicles ( ROV = Remotely Operated Vehicles)
• Other areas of expertise include marine law , fisheries and marine archeology ; Related disciplines are sea ice research, polar and climate research.

German marine research is primarily funded by the Federal Ministry of Research (BMBF) . One focus here is on the sustainable use and protection of the seas. Research projects that decipher the role of the oceans as CO 2 and heat storage in climate change are funded. Another research topic is rising sea levels and the effects on coastal regions. The littering and acidification of the seas and the associated consequences for biological diversity are also examined by the BMBF. Research in the field of marine technology , however, is funded by the Federal Ministry of Economics (BMWi) .

As a decidedly interdisciplinary science, oceanography requires close cooperation between its individual areas. Cooperation with neighboring earth sciences , in particular with geophysics and geodesy , comes under a. in the structure of the geoscientific Union IUGG , where the oceanographers form the 6th Association IAPSO (International Association for the Physical Sciences of the Oceans).

## History of scientific exploration of the seas

The first attempts at research into the oceans can be traced back to ancient times. They were closely related to the exploration of the earth. This included the course of the coast, the relationships between the coasts and islands and the design of the seas. The first descriptions of the coast ( Periplus ) were a summary by Ptolemy (approx. 150 AD). The corresponding measuring devices were missing for an exact representation. The introduction of the astrolabe and the Jacob's staff (around 1500) enabled astronomical calculations of the latitude of a place at sea, so that one could find islands once discovered and the coast when crossing the sea. It was not until the invention of the sextant (1731) and the ship's chronometer (1764) and the introduction of radio time signals that the problem of determining the location at sea was solved so that the geographical coordinates of a location could be determined at any time.

The tides are phenomena an effect of the tide-producing forces of the moon and sun . These forces were first explained by Isaac Newton (1687) from the general mass attraction of the earth - moon and earth - sun.

The first respected marine exploration expedition was conducted by Edmond Halley in 1698 to investigate the change in the location misalignment . The development of navigation was a prerequisite for carrying out other research, e.g. B. for researching ocean currents on the open sea. The Gulf Stream was discovered in 1513 . In 1603 the ocean currents were described. The first maps of the ocean currents were drawn in 1678 and 1786 with the aim of shortening the travel time between Europe and America for sailing ships .

The research of the winds has been carried out with great care since ancient times . The first map of wind conditions in the Atlantic Ocean was drawn by Edmond Halley in 1688. In the 18th century the beginnings of a systematic investigation of the oceanographic conditions of the world's oceans began. Hydrographic services are set up in various countries to carry out maritime surveying and to issue nautical charts , nautical manuals and tide tables . They are becoming more and more important for the rapidly developing shipping industry. The American naval officer Matthew Fontaine Maury began the systematic collection of ship observations in the mid-19th century. By evaluating these observations, he was able to publish wind and current maps in 1847, which contributed to a significant reduction in the travel times of sailing ships. His efforts to perfect the observations and to standardize them led to the first International Hydrographic Conference in Brussels in 1853 . This laid the foundation for an international observation service, in which around 6,000 fishing and merchant ships participate today.

The beginning of modern oceanography is the year 1872, when the HMS Challenger ( Challenger Expedition ) embarked on a multi-year marine journey around the world. The objective of this and the following expeditions in different countries, such as the Plankton Expedition 1889, the Pola Expedition 1890–1898 and the Valdivia Expedition 1898–1899, was the first inventory of the topographical , physical, chemical and biological conditions in the world's oceans, Little was known about the deeper strata at the time. Not only were the first basic findings collected, the required standard methods were also developed. The foundations for the development of theoretical oceanology were also laid, and the first realistic dynamic models were created. Over time, this made it necessary to abandon the rough sample measurements of the first inventory.

## Types of marine exploration trips

The oceanographic expeditions at sea can be divided into the following areas:

• General oceanographic recordings: They give a first general overview of the oceanographic conditions in the area, what is happening at the moment of the recording.
• Seasonal recordings: These were set by the International Council for the Exploration of the Sea in 1902 to be February ( winter ), May ( spring ), August ( summer ) and November ( autumn ). The recordings should be made in the first half of the month. In addition, a system of certain lines (ship courses) was established for individual areas of different seas, on which the recordings should be carried out in certain stations at sea (hydrological sections).
• Synchronous recordings: The seasonal recordings are carried out by several research vessels at the same time ( synchronously ) in order to obtain a synoptic picture of the distribution of the oceanographic elements in the shortest possible time .
• Recordings according to weather types: These recordings are made when a typical weather situation prevails that has an influence on the oceanic processes in the sea.

To be researched or measured:

• Ground relief: Use of an echo sounder to obtain a profile of the sea ​​floor through depth sounding ( bathymetry )
• Soil samples (disturbed and undisturbed): Determination of the physical and chemical properties of the soil (also acoustic)
• Water: transparency and color - hydro- photometric measurements, underwater radiation, extinction , see also: International Ocean Color Coordinating Group
• Sea state : wave height, wave direction, wave spectrum (e.g. Pierson-Moskowitz spectrum)
• Currents: three-dimensional flow velocity in m / s usually referred to as ${\ displaystyle {\ overrightarrow {u}}}$
• Water temperature: distinguishable in-situ and potential temperature, usually measured in ° C
• Water samples for the determination of salt content , pH value , gases , nitrogen , free carbon dioxide and hydrogen sulfide
• Ice conditions: amount, thickness, density, shape, passability and other properties of the ice
• Fluctuations in water level on the open sea due to high sea levels
• the radioactivity of sea ​​water
• Sand walks in coastal areas

## Oceans and secondary seas

Oceanic front systems in the southern hemisphere

A clear demarcation according to morphological aspects is not possible and is also not aimed for in nautical classifications, since in straits one does not choose the shortest connection as the boundary, but assigns the entire strait to one of the oceans.

The following hierarchy of boundaries results for oceans and tributaries:

• First order borders: borders between the four oceans ( Pacific , Atlantic , Indian , Arctic ).
• Second order boundaries: boundaries between sub-regions of the oceans; z. B. the equator as the boundary between the northern and southern parts of an ocean.
• Third order borders: borders to the secondary seas. They are best founded morphologically.
• Fourth order boundaries: boundaries between sub-areas of the secondary seas. They are usually set arbitrarily.
Oceans and secondary seas Area (in million km²) Volume (in million km³) medium depth (m) maximum depth (m)
Pacific 166.241 696.189 4188 11034
Australasian Mediterranean 9,082 11,366 1252 6504
Bering Sea 2.261 3.373 1492 3961
Sea of ​​Okhotsk 1,392 1.354 973 3379
Yellow - East China Sea 1.202 0.327 272 2681
Japanese sea 1.013 1.690 1667 3617
California Gulf 0.153 0.111 724 -
total 181,344 714,410 3940 11034
Atlantic 86,557 323,369 3736 9219
American Mediterranean 4.357 9.427 2164 6269
Mediterranean Sea 2.510 3,771 1502 4404
Black Sea 0.508 0.605 1191 -
Baltic Sea 0.382 0.038 101 459
total 94.314 337.210 3575 9219
Indian Ocean 73,427 284,340 3872 8047
Red Sea 0.453 0.244 538 2359
Persian Gulf 0.238 0.024 84 100
total 74.118 284,608 3840 9215
Arctic Ocean 9.485 12.615 1330 5220
Arctic Mediterranean 2.772 1.087 392 -
total 12.257 13,702 1117 5220
All in all 362,033 1349,930 3795 11034

## Seas and mainland

### Distribution of sea and land

Large landscapes of the earth : Basin on land: light blue. Pools in the sea: not highlighted

The earth's surface has an area of ​​510 million km². It is distributed over the sea with 361 million km² and on land with 149 million km².

It is different with the masses. Here the water of the oceans represents a small proportion of the earth's mass, the ratio of the earth to the oceans is 4166: 1, which corresponds to a mass of the oceans of 0.024% of the earth's mass. The impression that the areas on earth covered by water predominate is reinforced by the fact that land and water are unevenly distributed. Since the world's oceans are all connected to one another, any other point can be reached from one point on the earth's coast. Often longer detours have to be taken. Particularly long detours were necessary to bypass Africa and South America . Here the isthmuses of Suez and Panama offered special opportunities to shorten the detours through canals.

### Coastal

Coast of Corsica between Galeria - Gulf of Porto

The coast is generally the area where sea and land meet. On the coast, the lithosphere (mainland), hydrosphere (sea) and the earth's atmosphere meet . The forces in the contact area of ​​these three media give the coast special manifestations. Of particular importance are the geology of the earth's crust and the dynamics of the sea, but also the influence of weather and climate .

The oceanographic lines are:

the coastline at the level of the uppermost storm surge and surf effect
the shoreline with the maximum water limit

The following factors are involved in the design of the coast:

tectonic crustal movement (uplift and downward movement)
Nature of the rocks
Sea state , water level, tides and currents
Weather and climate , especially wind and frost (ice formation)
Flora and fauna (e.g. mangrove forests , mussel beds and coral structures)
Human in the form of coastal protection (eg. As dikes ) and harbor built

### Islands

Satellite image of some of the volcanic islands of the Hawaiian Islands - from west to east: Oʻahu , Molokaʻi , Lānaʻi , Maui and Kahoʻolawe
Satellite image of the East Frisian Wadden Islands
Coral island in the Pacific
Satellite image of the Bodden island of Ruegen

As islands surrounded by the ocean portions of the land surface are called. All parts are called islands, which, in their smallest form, are no longer flooded during normal floods. Depending on their location and affiliation, they are assigned to a continent or a sea basin, if they are grouped outside the shelf area of a continent in the group of oceanic islands, regardless of the type of origin they are. A distinction is made between individual islands and groups of islands ( archipelagos ) according to their proximity to one another . Large islands such as Greenland , England and Madagascar have a typical continental geographic structure, mostly small islands under 100 km² of land surface are under the influence of the sea. These islands are usually of particular interest in oceanography.

According to the formation, the following types of islands can be distinguished:

Built islands
• tectonic formation: uplift islands
• at the edges of clods
• Flounder Islands
• in the course of fold mountains
• Island chains
• Island arcs
• Island garlands
• volcanic formation: volcanic islands
• Formation by alluvial deposits: Alluvial islands
• Sand reef islands
• Sand plate dune islands
• Mud islands
• biogenic origin: coral islands, see atoll
• anthropogenic origin: artificial islands
• Marsh Islands
• Port islands
Isolated islands
• Formation by marine erosion ( abrasion ): island Cliffs
• Remaining islands
• Spit Islands
• Formed by marine ingression (drowning of a part of the country): Ria Islands
• Canale Islands
• Archipelago islands
• Bodden Islands
• Formed by tectonic faults: broken clod islands

## The ocean floor

### Ground relief

Flachsee and slope:

Flat lake or shelf - the part of the steps of the soil relief surrounding the continent from the limit of constant immersion to the recognizable slope in the depths of the ocean, approximately a water depth up to 200 m.
Shallow lake of an island - level of a soil relief of an island or archipelago from the border to the clearly recognizable bottom slope to about 200 m depth.
Continental slope - steeper part of the ground relief, as an extension of the outermost edge of the flat sea towards the deep sea

Depressions in the ground:

Basin - depression with a somewhat round, oval or elliptical shape ( lake basin )
Trench or channel - elongated depression in the deep sea ( deep sea channel )

Elevations of the ground:

Ingot - a long and wide bump protruding from the depths
Underwater mountain range - long and narrow elevation with steep slopes
Plateau - flat elevation with a horizontal surface and steep slopes
Summit - elevation with steep slopes
Underwater isthmus - long, narrow elevation with steep slopes connecting underwater elevations

### Oceanic sediments

In general, the sea floor does not consist of rock, but of deposited material ( sediments ). The ground samples allow a certain orientation of the ship's location, for fishing the condition of the bottom is important (use: bottom trawl ). The sediment deposits contribute to the understanding of the relief conditions. The marine sediments are examined according to their formation, composition and distribution.

The oceans and tributaries are the collecting basins for a large part of the rock destroyed ( weathering ) on the mainland , the product of the ocean itself. They are made up of locally changing parts that can be traced back to six different origins ( terrigenous , biogenic , polygenic , chemogenic , volcanogenic and cosmogenic (genetic sediment groups)).

The terrigenous sediments have their origin on the mainland. They come from mechanical weathering (rock disintegration) and chemical weathering, which is based on the dissolving power of water. As a result of various erosion processes, around 85% of the material reaches the oceans as a supply from the rivers (see fluvial sediment ). Another comes from the coasts and shallows , which are exposed to the erosive activity of the surf . Moraine material is also fed into the seas through glaciers and icebergs . The icebergs sometimes transport large stones from the polar region far into the ocean. Fine dust comes from the wind, e.g. B. from the Sahara , added. This material transport is closely related to the ocean current, under its influence the material is sorted according to grain size. Large pieces of rock already remain in the estuary , near the coast. The finer parts are carried far out into the ocean before they sediment. They form the main component of the red deep sea clay .

The biogenic sediments can be divided into three organic materials, land-based, benthogenic and planktogenic . The benthogenic consist of the residue of the fauna ( ichthyofauna ) and flora living on the sea floor . They collect near the coast as shallow water deposits. In the deep sea, the organic part is mainly that of animal and vegetable plankton, which can also be found on the surface of the water. Most of the dead plankton is released from the sea water when it sinks to the sea floor. Only a few sparingly soluble lime and silicic acid-containing residues get there, mainly different types of globigerins (belong to the foraminifera (root pods) and the shells of the pteropods or pteropods . Another important source is the nanoplankton , especially that of the coccolithophores . The sediment-forming diatoms and the radiolarians are common . The biogenic sediments are named after the animals or plants that are most commonly represented.

The only representative of the polygenic sediment is the red deep sea clay. This consists of almost 90% inorganic substances and comes from the mainland and the remains of the radiolarians.

The chemogenic sediments are new mineral formations that develop directly on the seabed through release from the seawater and other processes. They often contain glauconite , distant iron and manganese oxide , mostly in the form of tubers, granules and slices, as well as considerable proportions of cobalt , zinc and titanium .

The volcanogenic sediments are concentrated in the surroundings of the volcanoes. On the seabed there is volcanic silt, lava mixed with terrigenous sediments.

The cosmogenic sediments, they mostly come from interplanetary matter and are composed of small particles containing iron and silicate .

Annual sediment input into the oceans and tributaries

Factors Quantity in billions of tons
Rivers 18.0
erosion 0.3
Volcanoes 2.0
Biogenic factor 1.0
ice 0.4
Concretions 0.012
Cosmic dust 0.005
All in all 21.717

Micropalaeontological analysis is used to identify very small mussels and skeletons, with the help of which individual shapes can be counted. The result of this work is a characteristic of the microfauna of the seabed. For deep-sea sediments, micropalaeontology has become an important specialty of oceanography in connection with oil deposits .

### Evaluation of the oceanographic measurement results

The measurement results can be processed in a variety of ways. There are marine geological descriptions of the sea floor with signatures of the soil properties. When the soil samples taken from the marine area concerned are examined in the laboratory, they are entered as the result on a map with the coordinates of the sampling. This is where the complex work of correctly interpreting the analyzes according to their main types and mixtures (stones, gravel, sand, silt, mud, clay, etc.) begins for the marine geologist. These maps are of great importance for shipping. They mark good and bad anchorages and provide assistance for the journey through the ice. You qualify for the fishing good and bad fishing areas, in the coastal area of maritime works good or bad ground conditions are displayed. These maps are also of military importance: e.g. B. for a submarine that wants to hide or camouflage.

Marine geological sections are made if there are also holes for the soil samples. They give the opportunity to show the stratification of individual seabed types and their thickness in a section. The marine geological maps mostly show blatant transitions from one type of soil to another. In the border areas, the individual soil types usually only gradually change from one type of soil to the other.

## Ocean currents

Surface ocean currents 2004

Under the influence of various factors, in particular the warming of the water masses by the sun , the physico-chemical properties of the water usually only change in the area of ​​the surface layer up to a depth of 600 - 1,000 m, the so-called troposphere of the ocean. Furthermore, the wind has an effect on the sea surface, the cooling and the influence of the relief of the sea floor on the formation of ocean currents . As a result of this process and the mixing, the various ocean currents arise, they transplant the water masses from the area of ​​origin into other areas of the ocean, they cause them to sink into the depths or to rise from the depths to the surface of the water.

### Types of currents

Currents according to duration and persistence:

• constant currents
• periodic currents
• intermittent currents

Forces generating currents according to their origin:

Currents according to their direction of movement:

Currents according to the physical or chemical properties of the water masses:

• warm currents
• salty currents
• sweet or low-salt currents
• cold currents

Currents according to their stratification and location:

As a rule of thumb, this applies to all ocean currents, they differ in their duration and the force generated in them.

From these two conditions one can in most cases determine whether the given current is warm or cold, a deep or surface current is permanent or periodic.

Constant currents are those that are continuously present in the ocean current system at all times of the year, e.g. B. in the Atlantic Ocean the Gulf Stream or in the Pacific Ocean the Kuroshio . Periodically occurring currents are those currents that occur for a long or short period of time, but occur continuously, e.g. B. in the Indian Ocean the long-period monsoon currents. Occasional currents are caused by the action of short, locally very strong winds. Gravitational currents arise from the inclination of the isobar surfaces . The horizontal gradient of the pressure in the density compensation flow arises from the uneven and temporally different changes in the temperature and the salt content in the individual layers in the water, which results in a different density distribution. Barograde currents are caused by changes in the distribution of air pressure, which cause the water level to drop under high pressure areas and an increase in the water level under low pressure areas . Discharge flows are caused by an inclined position of the level, e.g. B. large amounts of runoff from rivers or estuaries that flow into a sea area, and also large local rainfall. Compensation currents arise somewhat apart from the others and are based on the fact that water is a coherent, inelastic liquid that tends to compensate for deficiencies in one place by influx from the other. If wind causes the water to flow out of an area, an influx from another sea area into the affected sea area sets in immediately to compensate. The wind and drift currents arise from the wind friction on the water surface and the wind pressure on the wave back. This sets the surface water layers in motion.

### Forces that act on the water masses

The forces that act on the still water masses are:

• Gravity as the most important and external force that acts on every mass particle in the sea
• static pressure: as an internal force that is represented by the pressure field in the form of isobaric surfaces
• Density of water : as an internal force whose distribution on the spot ( in situ ) or its reciprocal value (specific volume) is determined as a mass field.

The primary forces that generate and maintain movement include:

• Wind thrust, which is tangential to the surface of the water and has a significant effect on the primary forces because it creates large-scale drift currents and damming effects and internal pressure forces
• Attraction: Sun - Earth - Moon - these generate a periodic tidal wave, which affects water level fluctuations as ebb and flow and at the same time generates periodic tidal currents
• Change in air pressure : Currents on the surface of the sea trigger them, whereby the change in air pressure and intensity prove to be inconsistent
• Discharge or reflection force that arises from a slope of the sea surface, caused by local increases in water masses (e.g. rain )

The movements are also influenced by secondary forces:

• Frictional force : this movement reduces the speed and converts it into heat
• distracting earth's rotation : it influences the direction of movement of the water masses
• Centrifugal force : it only influences the water masses when the movements are curved
• Inertial force that has to be overcome at the speed of the water masses.

## Sea ice

### Types of classification

Ross Ice Shelf
Iceberg, 90% are under water, like in this photo montage

For centuries, oceanographers and nautical experts have endeavored to structure the multitude of types of sea ​​ice into a valid terminology and classification that also takes into account the regional characteristics of the ice behavior of individual seas and oceans. What has not yet been completely resolved in its form. There are several classifications:

The genetic classification - according to the shape, size, type of surface and color of the ice
The age classification - according to the age of the ice, as well as the stages of development and destruction of each type of ice
The classification according to the structure of the ice - according to the macro or micro structure of the ice
The physical-mechanical classification - properties of ice, especially strength
The geochemical classification - according to the chemical constituents of the ice, in connection with its various formation conditions
The nautical classification - location and distribution of ice and its passability for ships
The geographical classification - according to the features of the oceans and seas
The dynamic classification - according to the mobility of the ice, its drift and formation of the ice

### Types of sea ice

Accumulated pack ice wall (Grounded hummock) - Accumulated ice. May comprise a single pack ice wall or a line of accumulated pack ice walls.
Standing floe - Insulated floating ice, in a vertical or inclined position, surrounded by uniform ice.
Arctic pack ice (Arctic pack) - almost salty ice, it is older than two years, more than 2.5 m thick and has a wavy surface. The pack ice walls, which have been thawed several times, have a smooth shape.
Brummeis (growler) - ice blocks of small size approx. 3 - 5 m, often greenish in color and sticking out of the water a little. When they dive in and out of the water, a noise is created that is reminiscent of a humming sound.
Bay-ice - Closed ice that is more than a year old and on which there are walls of snow . The thickness with snow can be up to 2 m.
Thick winter-ice - Annual ice thicker than 30 cm
Ice banks (patch) - aggregated drift ice; its borders remain visible with an extension of less than 10 km.
Eisbarre (Ice-bar) - chain of ice, which is dammed by waves, currents and shock waves.
Iceberg - Floating or accumulated ice, from a height of over 5 m sea level, which has broken off from a glacier or ice barrier.
Eisblink (Ice-blink) - White lightening of the low clouds over an extensive ice field, glowing on the horizon.
Ice slush (sludge) - ice surfaces of white color, several centimeters thick; composed of ice and slush.
Ice-field - Floating ice of indeterminate size so that one cannot see the border.
Ice Belt - Long band of floating ice, can reach a width of over 100 km.
Ice island - Ice block detached from the ice shelf
Frost smoke - Fog resulting from the contact between cold air and warm sea water.
Ice-cake - ice under 10 m in size
Firneisberg (Glacier Berg) - Ice mass detached from the land, which has formed on the coast, with a height of up to 5 m above sea level or on a shoal.
Rafted ice - Press ice that results from the superimposition of two or more floating ice sheets.

## Marine fauna and flora

General oceanography does not go as far as the marine biologist or microbiologist in considering the creatures, flora and bacteria of the ocean . For the oceanologist, the creatures in the ocean are primarily indirect indicators of the chemical, physical, marine biological and dynamic processes in the ocean. In hydrobiology, living beings are divided into three groups, plankton , nekton and benthos .

The plankton includes all living beings that do not have large organs of movement and occur more or less in all water layers and float there. Also unicellular aquatic plants ( phytoplankton ), as well as small multicellular organisms ( infusoria ), furthermore that which falls under the category of zooplankton . The nekton is formed by larger swimming creatures, such as fish of all kinds, which are able to move independently in larger areas. Benthos is the collective name for all living things and plants that live and grow above, on or in the sea floor.

By finding representatives of one or the other group of living beings in individual areas or water layers, one can infer regional peculiarities of these water layers. z. B. on temperature, salt and oxygen content because they adjust their stay according to this peculiarity. If the natural conditions necessary for their stay change, they migrate, if they can move, and go to areas where their usual conditions prevail. From these processes, knowing the corresponding living conditions of individual animals, plants and bacteria, their presence as an indicator of the water can be determined without direct measurements.

## Vocational training as an oceanographer

Oceanographers mostly work either in research, marine protection or for marine technology companies. The training differs depending on the subject. In most cases, however, it applies to the above-mentioned subject areas that the actual study to become an oceanographer in Germany is only possible in Kiel and Hamburg, but also as a minor subject in Bremen, Rostock and Oldenburg.

For the physical oceanographer, the course up to the intermediate diploma does not differ from that of a pure physics course. Only then are focal points in oceanographic areas established.

For the chemical oceanographer, a preliminary diploma or diploma in chemistry is usually acquired and specialization as a chemical oceanographer only takes place within the framework of a doctorate. Lateral entry via geology or biology is also possible with a subsequent doctorate in marine chemistry. It is also conceivable to take a state examination at the university of applied sciences as a chemical-technical assistant, because then it is possible to study chemistry.

The entry into the other departments takes place in a similar way.

## literature

• Tom Garrison: Oceanography. An Invitation to Marine Science. 8th edition. CENGAGE Learning Custom Publishing, 2012, ISBN 978-1-111-99085-5 .
• Jörg Ott: Oceanography. Introduction to the geography and biology of the oceans. 2nd Edition. UTB, Stuttgart 1996, ISBN 3-8001-2675-3 .
• Ulrich Sommer : Biological Oceanography. 2nd revised edition. Springer, Stuttgart 2005, ISBN 3-540-23057-2 .
• Robert H. Steward: Introduction to Physical Oceanography. Open Source Text Book, 2008 ( oceanworld.tamu.edu , English).
• Pierre Tardent: Marine Biology: An Introduction. 3rd, unchanged. Edition. Thieme, Stuttgart / New York 2005, ISBN 3-13-570803-9 .