Species | Glossaire eau, milieu marin et biodiversité

Benthos

Sens commun

All organisms found at the bottom or on the seabed. E.g. macro-algae are attached to the bottom, they are part of the benthos (unlike unicellular algae or micro-algae that float passively and are therefore part of the phytoplankton). Molluscs, crustaceans and worms are also part of the benthos, although their eggs are planktonic. It is the same with echinoderms.

Source

According to Ifremer

Benthophagous

Sens commun

Describes species feeding on organic matters on the bottom.

Source

According to Ifremer

Benthic

Sens commun

Adjective that describes the water-sediment interface (= water-lithosphere interface) of an aquatic ecosystem, regardless of its depth (the bottom of lakes or of rivers or of the sea). Also describes an organism living on the river bottom or sea bed (macroinvertebrates, for example).

Source

According to the Ministry of Ecology

Bacteria

Sens technique

Extremely small unicellular prokaryotic microorganism, classified either in independent kingdom, neither animal nor plant, or classified with the fungi as Schizomycophita. Their form is highly variable, either living as saprophytes (soil, water, living organism), or as a parasite of humans, animals and plants.

Source

According to Ifremer

Allis shad

Sens technique

Fish species belonging to the Clupeidae family (such as sardine and herring). The allis shad are among the anadromous species (i.e. which swim up rivers to spawn in the middle part of the rivers). As such, their populations have paid a heavy price to river development (dams without fish pass facilities, extraction of gravel changing the spawning, etc). Their presence is therefore a good indicator of the status of a river development. Two species of allis shad are present (and exploited) in French waters: the allis shad (Alosa Alosa) and twaite shad (Alosa fallax).

Source

According to Ifremer

Abundance

Sens technique

Quantitative parameter for describing a population. The complete quantification of a fauna or flora population is usually impossible. By extension, it means a number of individuals in a given category: population, recruitment, stock, relative to a time or surface unit.

Source

According to Ifremer

Diatom Biotic Index

Sens technique

Index for assessing the biological quality of the water of a river through an analysis of benthic diatom flora.

Source

Vertebrate

Plankton

Sens commun

All plants (phytoplankton) or animals (zooplankton) of very variable sizes and belonging to a variety of groups, that are living in suspension in water and whose more or less passive movements are determined by currents.

Source

According to Poitou-Charentes Regional Council

Migration

Sens technique

Movement of a group of individuals between two distinct habitats under the influence of periodic (climate, food and spawning) or accidental factors, and their return later to the place of departure. Most frequently, these movements are necessary for the fulfilment of the life cycle of the species: gamic migration (related to reproduction), ontogenetic migration (related to the movement of individuals during their growth), trophic…

Source

According to Poitou-Charentes Regional Council