Hello to the entire steemit community! Today I come to tell you about a small world that surrounds the seas and many do not know that these little beings exist. And it's the plankton.

At the end of this post I will show you a work I did with plankton

Plankton is the set of organisms of small size (typically < 3 cm) whose main characteristic is to inhabit the water column with limited capacity to counteract the water currents. In this way, any organism that complies with this characteristic will be part of this aquatic community. The term "plankton" comes from the Greek meaning wandering which was coined in 1887 by the German Victor Hensen to describe the organisms that derive with marine currents and freshwater.

Under this operative definition, the composition of organisms of this community then turns out to be widely diverse including virtually all the lines that inhabit the aquatic environment, and although bacteria and viruses are considered part of this community, broadly distinguish two components : phytoplankton that includes organisms that obtain their energy by the energy of light and nutrients through the process of photosynthesis (microalgae) and zooplankton, which are the organisms that obtain their energy by ingesting other organisms (heterotrophic component).

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Phytoplankton They are the primary producing microalgae of the plankton with different forms of cellular organization: solitary cells, in chain, forming filaments, in cellular aggregates forming marine snow. The main groups of microalgae that make up phytoplankton are diatoms, dinoflagellates, chlorophytes, cyanophytes (also known as cyanobacteria), euglenoids, rafidophytes, coccolithophorids, silicoflagellates, among others. Depending on the freshwater or marine environment, they will have representatives or not of these groups and their abundance and diversity will vary. Since it is the photosynthetic component, they constitute the first link of the food web in aquatic systems together with the primary producers that inhabit the bottoms of the bodies of water.

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Zooplankton Constituted by all the consumers that constitute in their great majority secondary and tertiary producers. This group is constituted by generally adult microscopic organisms and their larval phases (holoplankton), and by the larval stages of other organisms that in adult form inhabit the aquatic bottoms or the water column but counteracting the movement of the currents. Some of the most abundant and characteristic groups of zooplankton organisms are the copepods, cladocerans, rotifers, cnidarians, ketognaths, euphausiids and the larvae of the fish that, due to their socio-economic relevance of juvenile organisms and adults, generally study and describe with the term " Ichthyoplankton ". Like phytoplankton, depending on the environment in which they are found, whether freshwater or marine, each of the groups or species of zooplankton will vary their diversity and abundance. A relatively less studied component of zooplankton are its parasites that constitute a diversity several orders of magnitude greater than the same phytoplankton and zooplankton organisms since every organism that exists on the planet is prone to infesting or being infected by multiple parasites.

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Permanence in the plankton. Most of the organisms spend their entire life cycle in the water column forming part of this community of plankton and these have been defined as holoplankton (for example: diatoms, dinoflagellates, copepods, euphausids and cladocerans) while others remain only a few. phases and we know them as meroplancton (for example: larvae of crustaceans, larvae of echinoderms, larvae of fish, gametes of macroalgae and aquatic plants).

What sizes are the plankton organisms?

The organisms of the plankton are generally microscopic so for their study we use optical microscopes (compounds or stereoscopic) or scanning electron microscopes to observe structures of microorganisms or complete organisms of few microns in length. There are also planktonic organisms that we can observe with the naked eye since they reach sizes> 1 mm to organisms that can measure several centimeters in length. In the case of cnidarians, jellyfish are the largest planktonic organisms that we can distinguish with the naked eye, since their size varies from a few millimeters to <1 meter in diameter and several meters in length of their tentacles.

With an operational criterion, the plankton have been classified according to the size of the organisms: picoplankton <2 microns (micron = one millimeter of millimeter), nanoplankton of 2 to 20 microns, microplankton of 20 to 200 microns, mesoplankton of 200 microns to 2 cm, macroplankton from 2 to 20 cm, and megaplankton> 20 cm. Some groups of organisms such as free-living bacteria or adhered to participates as marine snow are defined as bacterioplankton.

Importance

Since the plankton community is made up of most of the organisms present in the pelagic ecosystem and contains a relevant proportion of the primary producers and secondary and tertiary producers, it constitutes the largest available biomass where the trophic plot begins in aquatic environments. The plankton performs the greatest mobilization of biomass of the planet daily in its daily vertical migration, which in terms of energy and mobilized biomass constitutes what is known as the biological pump that controls a large part of the organic biogeochemistry of the ocean. Phytoplankton contributes about 50% of the planet's primary production. The knowledge of the diversity biogeography, abundance, ecology, physiology and evolution of this community, are indicators of the productive potential of the ecosystems that, for the interests of humans, contribute to the biomass available for fisheries. Plankton organisms can be useful indicators of changes in ecosystems due to their rapid response to environmental conditions dictated by their relatively short life cycles and sensitivity to pollution.

In biotechnology, plankton organisms are used for their culture as a source of food in aquariums and for obtaining other food products for the development of fisheries. They are also used in studies of toxicity and obtaining pigments, among many other applications of interest to man

I have had the pleasure of working with these organisms and I am going to show you one of the samples that I obtained in the Laguna Morro, on the island of Margarita, Venezuela.

This worked consisted in going for 8 months approximately to this laduna and collecting water samples, in order to collect a significant amount of zooplankton and phytoplankton; these species were identified taxonomically.

We also get other types of organisms such as shrimp larvae:

Of all the species that we got, the most common were:

Acartia tonsa

Euterpina acutifrons

Oithona nana

Shrimp nauplii.

Evagne normani