Histroy of marine benthos ecology

Ever since the middle of the 19th century naturalists have been investigating and desribing the sea floor of the Baltic Sea. Scientists from Kiel like Karl Möbius (1825-1908) played a big part in this. Möbius first started in the Baltic Sea and continued later with the North Sea to investigate the animal sea floor community. Field of investigation was the Benthos - 'The biocoenosis at/in and on the floor of waterbodies' according to new definition. From the ecological point of view besides molluscs, snails, crustaceans and polychaeta also demersal fish (like small fish, flatfish and cod) are part of this community. Additionaly benthic microorganisms (bacteria and funges) also belong to the zoobenthos. It was Karl Möbius who started with the aim to explain the commercial importance of oyster reefs of northern part of the Wattenmeer to politicans by creating the expression  'biocoenosis' in 1877. From this need to explain biological background information to unaware decision makers the basis for modern benthos ecology was established. In 1866, Ernst Haeckel characterised independently the expression of 'Ecology'.

Benthos can be classified into zoo- (invertebrate and vertebrates) and phytobenthos (macro algae and seaweed). The area called 'Phytal' is populated by phytobenthos and therefore dependant to sunlight. Because of the needed light for photosynthesis the phytal is limited to te upper 15-20m of our waterbodies. The zoobenthos is not limited by this, but other factors like oxygen supply are a limiting factors for the zoobenthic community.

Benthic organisms populate the sea floor from the beach to the deepest depth, while marine algae and seaweed are limited by physiologic conditions to the lighted part. This part is so called the 'euphotic zone'. The zoobenthos populates everything from soft, muddy sediments to sandy sediments and hard substrates like stones, rocks, seashells and human structures like harbour piers, pillars, sheet piling, ship hulls and oil riggs. These structures are referred to as secundary hard substrates.

The investigation of benthic fauna is a very reliable measure for the environmental quality, because the mainly stationary benthic organisms integrate over time the changing environmental conditions. For this reason, the impact of unrecognized environmental effects can be derived from the benthic fauna composition.

While trying to find the natural communities there was also the need to classify the fauna by size. The classification used nowadays is mainly based on methodological sequences for sampling and extraction of benthic fauna instead of biological properties. Becaus eof this the benthic soft bottom fauna is classifyed in:

1. Macrofauna. The part of the benthic community that is sampled by a 1mm sieve (some times 0.5mm depending on the study aim)
2. Meiofauna. The part of the benthic community that runs through a 1mm sieve but is reationed in a 40µm sieve. This is also called the 'sand gap fauna'
3. Microfauna. The part of the benthic community that can only be extracted by special methods, because of the short life time and the few remains (Ciliata etc.)

This classification can bee regarded as working terminology and does not consider the intermediate organisms or life stages (Big meiofauna or larval stages of macroorganismes and lots more).