Product Code Database
Neuston, also called pleuston, are that live at the surface of a body of water, such as an ocean, estuary, lake, river, wetland or pond. Neuston can live on top of the water surface or submersed just below the water surface. In addition, microorganisms can exist in the surface microlayer that forms between the top- and the under-side of the water surface. Neuston has been defined as "organisms living at the air/water interface of freshwater, estuarine, and marine habitats or referring to the biota on or directly below the water's surface layer." (2025). 9789401788007, Springer Netherlands. ISBN 9789401788007
Neustons can be informally separated into two groups: the phytoneuston, which are floating at the water surface including cyanobacteria, filamentous algae and free-floating aquatic plant (e.g. mosquito fern, duckweed and water lettuce); and the zooneuston, which are floating such as (e.g. ) and (). The word "neuston" comes from Greek language neustos, meaning "swimming", and the noun suffix -on (as in "plankton").Merriam-Webster Dictionary: neuston. Accessed 18 December 2021. This term first appears in the biological literature in 1917. The alternative term pleuston comes from the Greek plein, meaning "to sail or float". The first known use of this word was in 1909, before the first known use of neuston.Merriam-Webster Dictionary: pleuston. Accessed 18 December 2021. In the past various authors have attempted distinctions between neuston and pleuston, but these distinctions have not been widely adopted. As of 2021, the two terms are usually used somewhat interchangeably, and neuston is used more often than pleuston.
The neustonic community structure is conditioned by sunlight and an array of endogenous (organic matter, respiratory, photosynthetic, decompositional processes) and exogenous (atmospheric deposition, inorganic matter, winds, wave action, precipitation, UV radiation, oceanic currents, surface temperature) variables and processes affecting nutrient inputs and recycling. Furthermore, the neuston provides a food source to the zooplankton migrating from deeper layers to the surface,Hempel, G. and Weikert, H. (1972) "The neuston of the subtropical and boreal North-eastern Atlantic Ocean. A review". Marine Biology, 13(1): 70–88. as well as to roaming over the oceans.Cheng, L., Spear, L. and AINLEY, D.G. (2010) "Importance of marine insects (Heteroptera: Gerridae, Halobates spp.) as prey of eastern tropical Pacific seabirds". Marine Ornithology, 38": 91–95. For these reasons, the neustonic community is believed to play a critical role on the structure and function of marine food webs. Yet, research on neuston communities to date focused predominantly on geographically limited regions of the oceanZaitsev, Y. P. (1971). Marine Neustonology. ed. K. A. Vinogradov (Jerulasem: Israel program for scientific translations).Ebberts, B. D., and Wing, B. L. (1997). "Diversity and abundance of neustonic zooplankton in the North Pacific subarctic frontal zone". U.S. Department of Commerce, NOAA Technical Memorandum NMFS-AFSC-70. or coastal areas.Padmavati, G. and Goswami, S.C. (1996). "Zooplankton distribution in neuston and water column along west coast of India from Goa to Gujarat". Indian J. Mar. Species, 25: 85–90. Consequently, neuston complexity is still poorly understood as studies on the community structure and the taxonomical composition of organisms inhabiting this ecological niche remain few, and global scale analyses are yet lacking.
Marshall and Burchardt divide neuston into three ecological categories:
By size: greater duckweed, Lemna minor and Wolffia arrhiza
Red fire ants have adapted to contend with both flooding and drought conditions. If the ants sense increased water levels in their nests, they link together and form a ball or raft that floats, with the workers on the outside and the queen inside. The brood is transported to the highest surface. They are also used as the founding structure of the raft, except for the eggs and smaller larvae. Before submerging, the ants will tip themselves into the water and sever connections with the dry land. In some cases, workers may deliberately remove all males from the raft, resulting in the males drowning.
The longevity of a raft can be as long as 12 days. Ants that are trapped underwater escape by lifting themselves to the surface using bubbles which are collected from submerged substrate. Owing to their greater vulnerability to predators, red imported fire ants are significantly more aggressive when rafting. Workers tend to deliver higher doses of venom, which reduces the threat of other animals attacking. Due to this, and because a higher workforce of ants is available, rafts are potentially dangerous to those that encounter them.
Neustonic animals are primarily adapted to float upside-down on the ocean surface, similar to an inverted benthos, and form a unique subset of the zooplankton community, which plays a pivotal role in the functioning of marine ecosystems. Zooplankton are partially responsible for the active energy flux between superficial and deep layers of the ocean. Zooplankton species composition, biomass, and secondary production influence a wide range of trophic levels in marine communities, as they constitute a link between primary production and secondary consumers. constitute the most abundant zooplankton taxon in terms of biomass and Biodiversity worldwide. Consequently, changes in their community composition can impact the biogeochemical cycles and might be indicative of climate variability impacts on ecosystem functioning.
Historically, zooplankton assemblages research has focused mainly on taxonomic studies and those related to community structure. However, recently, research has veered toward an alternative Phenotypic trait, providing a perspective more focused on groups of species with analogous . This allows individuals to be classified into types characterized by the presence/absence of certain alleles of a gene, into size classes, , or functional groups (FGs). Functional traits are affecting organism fitness, growth, survival, and reproductive ability. These are regulated by the expression of genes within species, and the expression of traits regulate, in turn, the species fitness under contrasting biotic factor and abiotic factor. Moreover, a specific functional trait can also develop from the interactions between other traits and environmental conditions, leading to a given trait grouping being favoured under certain conditions. Zooplankton traits can be classified in accordance to ecological functions – feeding, growth, reproduction, survival, and other characteristics such as morphology, physiology, behaviour, or life history. Particularly, feeding strategies and trophic level are relevant to establish feeding efficiency and associated predation risk. Additionally, they facilitate the understanding of ecosystem services associated with zooplankton, such as the distribution of fisheries or biogeochemical cycling while also allowing the positioning of zooplankton taxa in the food web.
Hermatobates are a genus of quite rare wingless marine bugs known only from coral reefs in the Indo-Pacific region. During low tide they move over water surfaces around coral atolls and reefs similar to the more familiar water-striders, staying submerged in reef crevices during high tide.
See also
External links
|
|
