plankton - it is a phenomenon of nature?So call not separate entities, but a group of aquatic organisms drifting in the water column.In the traditional classification of all the inhabitants of the oceans, rivers and lakes of land divided into three groups: nekton, benthos and plankton.The first - a fish, squid, amphibians and other animals that are actively moving.Attached lifestyle leads the benthos (sponges, worms, mollusks, and others).
Plankton - what is this?
Translated from the Greek name of the passive motion in water organisms means "wandering", "soaring".Plankton - are living beings who do not have active means to move or limit their use.By belonging to the kingdoms of nature plankton in the sea and fresh water is divided into 3 main types: bacteria, phytoplankton and zooplankton.All these organisms inhabit waters from large freshwater and seawater to small puddles.
representatives of phytoplankton - algae and cyanobacteria themselves produce organic matter.They need light to maintain photosynthesis.Zooplankton - a simple, crustaceans, coelenterates, eggs, larvae, which feed on other small organisms.
There is another classification, which takes into account not the way to power, and the size of the organisms.Under this system, a group, since nannoplankton (viruses) and ending megaplanktonom.The most widespread on the planet - the smallest creatures (about 2 m).The existence of this group found only in the 1980s.By megaplanktonu include jellyfish, cephalopods, ctenophores and other aquatic life, the body of which more than 2 cm in length.
Why plankton does not sink?
density of the bodies of some organisms in the oceans is close in meaning to the specific gravity of water.Plankton - is something very easily, freely floating in the environment.Those living beings, body density which is greater than one, in a suspended state holds its own physical activity.
list the features of the structure of plankton, which are allowed to exist in the surface layer of water:
- microscopic or small size;
- flat shape of the body;
- tissue saturation with water (98%);
- copious mucus on the surface of the body;
- gas vacuoles;
- fat inclusions;
- outgrowths, needles, hairs, bristles at the body surface;
- a small amount in the tissues of heavy chemical elements.
Each species present, not all but 2-3 of the device list.There is another feature that allows you to not sink unicellular algae - the union in the colony.The amazing ability of some organisms soaring - the change in density depending on the water temperature.In a cold environment, the proportion of the body increases, and warm - is reduced, thus preventing immersion.
phytoplankton and bacterioplankton
groups of organisms, is about 90% of the plant kingdom, including green sea plankton and the inhabitants of fresh water.It volvoxes, dinoflagellate, Euglenophyta, Cryptomonad, cyan, green bacteria.They contain in the body pigment chlorophyll as terrestrial plants.Phytoplankton dissolved in water absorbs carbon dioxide for photosynthesis uses nutrients.Some representatives can fix nitrogen, hydrogen sulphide.
favorable conditions for growth and reproduction of phytoplankton:
- water rich in carbon dioxide;
- sunlight;
- presence of mineral elements;
- moderate temperature and salinity;
- small depth.
Sometimes there is a sharp increase in the population of phytoplankton, or "bloom" of water.In the ocean, a similar phenomenon is observed in the vast area covering hundreds of square kilometers.The big environmental problem is the "bloom" of fresh water consumed for drinking purposes.Some representatives of phytoplankton produce toxins harmful to fish and humans.
Zooplankton
animal plankton - what's that?An important part of any aquatic ecosystem.Without this group of organisms, many inhabitants of the oceans, seas, rivers and lakes would not receive the necessary nutrition.Some representatives of the movement organs of zooplankton is not using them to travel long distances.Protuberances, bristles, needles, tentacles need such organisms swimming in the adjacent water volume and vertically.
widespread horizontal movement provided "adrift" and currents.Thus, the larvae of crustaceans, echinoderms, fish eggs in the plankton are less than two months.During this period they carried away from the original habitat for hundreds of kilometers.As part of zooplankton can be found larval stages of sponges, sea anemones, worms, clams, crabs, lobsters and starfish.Numerous members of the group - copepods and krill, whose lives are almost entirely dependent on the availability of food - diatoms.
who eats plankton?
the food chain, each organism is important, without it there can not be an integer.Small water plants and bacteria involved in photosynthesis, are the producers of organic substances.Pets shapes drifting in the water organisms are the main consumers of tiny algae and bacteria.Zooplankton serves as a link between bacteria, algae, and the inhabitants of large bodies of water.
Tiny crustaceans, krill and pteropods eat a lot of fish, shellfish, some birds and even baleen whales.Reducing the number of plankton threaten the well-being of the entire ecosystem of the oceans.Scientists are studying this issue in connection with global climate change, affecting temperature, salinity and water transparency - the habitat of the plankton.
