Seston (from ) refers to the particles suspended in bodies of water, such as oceans, lakes, and rivers. Small particles of seston may be formed by the breaking down of larger particles amidst the crashing of waves, mixing of water currents, or slow disintegration. The organic constituents of seston include

plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...

and

detritus In biology, detritus ( or ) is organic matter made up of the decomposition, decomposing remains of organisms and plants, and also of feces. Detritus usually hosts communities of microorganisms that colonize and decomposition, decompose (Reminera ...

from decomposing organisms; the inorganic components of seston are of

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...

origin, essentially particles of mud suspended in the water column. Seston is used by many species in their day-to-day activities. Some examples are

barnacle Barnacles are arthropods of the subclass (taxonomy), subclass Cirripedia in the subphylum Crustacean, Crustacea. They are related to crabs and lobsters, with similar Nauplius (larva), nauplius larvae. Barnacles are exclusively marine invertebra ...

mussel Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other ...

scallop Scallop () is a common name that encompasses various species of marine bivalve molluscs in the taxonomic family Pectinidae, the scallops. However, the common name "scallop" is also sometimes applied to species in other closely related famili ...

coral Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...

sea anemone Sea anemones ( ) are a group of predation, predatory marine invertebrates constituting the order (biology), order Actiniaria. Because of their colourful appearance, they are named after the ''Anemone'', a terrestrial flowering plant. Sea anemone ...

s, sea squirts, and

sea cucumber Sea cucumbers are echinoderms from the class (biology), class Holothuroidea ( ). They are benthic marine animals found on the sea floor worldwide, and the number of known holothuroid species worldwide is about 1,786, with the greatest number be ...

s. Suspension feeders and filter feeders like

whale Whales are a widely distributed and diverse group of fully Aquatic animal, aquatic placental mammal, placental marine mammals. As an informal and Colloquialism, colloquial grouping, they correspond to large members of the infraorder Cetacea ...

s also rely on seston as a food source. Nutrient-rich seston particles can support the local ecosystem by providing nutrition to organisms. The higher the amount of organic matter in the seston, the more nutritious it is for the suspension feeders who count on seston as a food source. Many of these animals have adapted to be able to eat both organic and inorganic seston. Animals that eat seston also have to adapt because the seston is not always present or may have periods of time when it is less nutritious. They adapt by eating more when it is there or by storing it to eat later when it would otherwise be unavailable. Studies of rivers have shown that downstream seston is more nutritious than it is upstream. While seston is necessary for many animals and in many ecosystems, it can also be harmful in large quantities. Sometimes human activities like fishing and farming that generate nutrient-rich

surface runoff Surface runoff (also known as overland flow or terrestrial runoff) is the unconfined flow of water over the ground surface, in contrast to ''channel runoff'' (or ''stream flow''). It occurs when excess rainwater, stormwater, meltwater, or other ...

can make the presence of organic seston increase dramatically. This sudden increase can destabilize the

ecosystem An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and en ...

if there are not enough organisms that eat that seston to make up for the increase. As the amount of seston grows, it may undermine the growth of other organisms, a process known as cultural eutrophication. One example of this process Lake Okeechobee in the

U.S. The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 states and a federal capital district, Washington, D.C. The 48 contiguous ...

state of

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

. Runoff from nearby farming increases the nutrients in the lake and causes the amount of algae to grow. Especially in the more shallow parts of Lake Okeechobee, the algae grows very well because it requires sunlight to carry out the process of photosynthesis to make food for itself. Because parts of Lake Okeechobee are so shallow, there is a high degree of light penetration through the water, which allows more of the algae to receive the sunlight it needs. Because the algae needs a warm and sunny environment, this is especially a problem in warmer climates like that of Florida. Some of the algae bloom is blue-green algae, which is also known as

cyanobacteria Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteri ...

. It grows very quickly when it has nutrition from

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

and

phosphorus Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...

. The algae bloom decreases water quality and can make people and animals sick. Some symptoms in people include nausea and vomiting, but the worst side effect could be liver failure. Since Lake Okeechobee waters are released to the ocean through canals to the east and west, coastal areas in Florida are affected too. The algae bloom has caused businesses near the ocean to close and hurt tourism revenues in recent years. Florida has even declared a state of emergency in the past because of the algae bloom.

References

Biological oceanography Limnology Aquatic ecology {{Ocean-stub

See also

References