© Barbara Wojtasik, HydroBiolLab
Citation: Wojtasik B. 2016. Meiobenthos – different definitions and criteria applied [In:] B. Wojtasik, J. Sosiński, P. Pacyga. MeioEco.com application for ecological status analysis (http://portal.meioeco.com), 2016 r.

Meiobenthos – different definitions and criteria applied

Key words: meiobenthos, macrobenthos, size, definitions, errors, MeioEco

Abstract
Benthic organisms, apart from taxa classification, are divided into three size-dependent groups: microbenthos, meiobenthos and macrobenthos. Each group contains organisms of different taxonomic units. In the case of microbenthos the lower size limit is unrestricted, similarly the upper size limit for macrobenthos is not specified. Both values, the upper and lower size limit, are essential for meiobenthos. Different definitions of meiobenthos do not specify exactly the sizes of studied specimens belonging to the group and consequently they can belong to two size classes (meio- and macrobenthos and meio- and microbenthos) simultaneously or not fall into any of them. The lack of an unambiguous definition specifying the size criterion for meiobenthos influences obtained results and possibility of comparison.

Introduction
The ample literature concerning benthic organisms often provides size dependent group classification into microbenthos, meiobenthos and macrobenthos. Each group contains organisms belonging to different taxonomic units. In the case of microbenthos the lower size limit is unrestricted, similarly the upper size limit for macrobenthos is not specified. Both values, the upper and lower size limit, are essential for meiobenthos. There are different definitions of meiobenthos size (Table 1) and also various definitions of macrobenthos lower size limit, which is essential with regard to meiobenthos (Table 2). Therefore some organisms can be classified as belonging to two groups simultaneously or to none of the above mentioned groups. The concept that these are organisms passing through a sieve of given mesh size (different in particular definitions) leaves a wide margin of arbitrariness depending on animals' measurements (longitudinal and transverse), their flexibility, type of preservatives used for samples (Gaston et al. 1996) or alive animals sieved, presence of limbs or setae, type of bottom sediment they have been collected with, rapidity of water flux used for sample washing and mesh type. Inaccuracy of the definition applies even to the term of 'mesh size', as samples are washed with the use of frames with mesh stretched, where 1.0 mm means the length of a square side or the mesh diameter. Sieves with rhombus or polygonal mesh are also used. The information that the mesh is a 1.0 mm square (Żmudziński et al. 2002) in the definition of meiobenthos size is included only in few papers. There is a lack of detailed information concerning efficiency of the sieve washing process for particular taxa, and especially concerning loss during washing with respect to the bottom sediment type the sample has been collected with. Whereas, the methods of zoocenological analysis of isolated and identified organisms is presented meticulously. Since whole large functional groups, like macrobenthos and meiobenthos, are being more commonly used to assess water quality (Hawkes 1979, De Pauw & Vanhooren 1983, Särkkä 1992, Simboura & Zenetos 2002, Clarke et al. 2003, Czerniawska-Kusza 2005, Dye 2005, Chainho et al. 2007) it seems essential that the definition concerning conditions under which a given organism is classified as belonging to a particular size group should become more specific. Meiobenthos as a complex group of organisms is subject to further divisions, among others to marine and freshwater, permanent (specimens belonging to the given group throughout their life-cycle) and temporary (macrobenthos young stages). Although according to some authors (Geire 1993, 2009, Szymelfenig et al. 1995, Soltwedel 1997, Gal’tsova et al. 2004, Radziejewska et al. 2006, Brandt et al. 2007) Protista, particularly Foraminifera are regarded meiobenthos representatives while others restrict marine meiobenthos to Metazoa (Reise 1979, Sommerfield & Warwick 1996, Schizas & Shirley 1996). Despite advanced statistical analyses: Canoco (Braak & Similauer 1998), Primer (Clarke & Gorley 2006) used among others to estimate meiobenthos group, with the lack of regulated meiobenthos definition or standard procedure of isolating meiobenthos specimens from sediment, the obtained results are often incomparable and in many cases marred with error. The aim of the presented paper is the analysis of various criteria applied to meiobenthos and macrobenthos (the lower size limit) size and a proposal for standardisation of the definition and classification methodology while maximally preserving the so far applied criteria.

Material and methods
The analysis of the variety of meiobenthos definitions and size criteria used in practical procedures, macrobenthos lower size limit applied in research was based on the selected specialist literature. From available scientific literature only a one article sample was chosen for one size criterion. Results shown on Table 1 and Table 2, Fig.1 and Fig.2.

Results and discussion
The detailed data concerning the size of meiobenthos, the lower size limit of macrobenthos and the upper size limit of microbenthos, are presented in Table 1. The above specification shows undoubtedly that the size of organisms classified as meiobenthic can be treated very arbitrarily. Though the methodology states the lower size limit as 0.5 mm or 1.0 mm for macrobenthos (resulting from the sieve employed), the results frequently include only the groups which are obligatorily macrobenthal at the mature stage (Houston & Haedrich 1984, Bick & Arlt 2005), even though mature specimens of numerous species of Cladocera, Ostracoda and Copepoda exceed 0.5 mm and in many cases 1.0 mm (Sars 1903-1911, Bronstein 1947, Lang 1948, Rylov 1948, Loeblich & Tappan 1964, Dussart 1967, 1969, Delorme 1970, Flößner 1972, Sywula 1974, Athersuch et al. 1989, Huys et al. 1996, Rybak & Blędzki 2005, Murray 2006). Although the more of species of systematic groups such as Foraminifera, Nematoda, Cladocera, Ostracoda, Copepoda-Cyclopoida are enumerated as belonging to macrobenthos (size definition), they can be found only in few works concerning macrobenthos: Foraminifera (Wlodarska-Kowalczuk et al. 1998), Nematoda (Kröncke 1994), Ostracoda (Da Fonseˆca-Genevois et al. 2006). Another methological element is washing samples through a sieve (0.5 mm and 1.0 mm respectively) and regarding as meiobenthos all the organisms that passed through the sieve. As a result a large group of animals is not taken into account in the analyses – that is all those traditionally regarded as meiobenthos and which are larger than mesh size if 100 % efficiency of the washing process is assumed. In the case of a less efficient washing even larger a group is not subject to analyses. The method of sorting the organisms, which corresponds to the procedure used in granulometry (Pfannkuche & Thiel 1988, Soltwedel 1997), cannot be its equivalent due to a few major reasons: 1. meiobenthic organisms have different shapes, very often dissimilar from spherical which is ideal for washing, 2. the specific weight of meiobenthic organisms is usually significantly smaller than that of sediment grains which impedes the procedure, 3. the lack of compact or homogenous body built of many taxa and the presence of numerous limbs and setae affects the retention of washed specimens on mesh, on larger plant parts or on other organisms retained on the sieve, 4. a significant difference between body length and width causes the organisms' retention on the sieve (hydrodynamic – Stokes’ law, Reynolds number), 5. physical properties, i.e. liquid viscosity, surface tension and fraction counteract the free passing of specimens through a sieve. The washing process on a sieves was done in different parts in procedure of collected meio- or macrobenthos: before preservation (Kröncke 1994, Wlodarska-Kowalczuk et al. 1998, Bick & Arlt 2005, Feder et al. 2007) or after preservation (Guerrini et al. 1998, Kotwicki et al. 2004). This has an influence on the results (hydrodynamics rules as Stokes’ law, Reynolds number). The method of sorting the organisms on a sieve is not perfect. Theoretically the least loss was while washing Ostracoda, Foraminifera and juvenile Mollusca, what is undoubtedly due to their body shape and relatively high specific weight (Loeblich & Tappan 1964, Gal’tsova et al. 2004, Wiśniewska (Wojtasik) 2003). Different washing efficiency for particular meiobenthic taxonomic units is of a great importance for analysing biodiversity of communities and particularly for determining the occurrence density and relative number of particular taxa, as well as for other calculations like biomass. The standardisation of methods and criterion could constitute a new direction in ecohydrological monitoring and evolution of reservoirs, rivers, and seas using a group of meiobenthos as a bioindex, in particular of MeioEco method (Fig. 4) (Wojtasik 2009, Wojtasik 2013 a, b)

Conclusion
The conducted analyses show that the classification criterion according to the size of organisms is commonly applied to meiobenthos, whereas the size-taxonomic criterion is more often used for macrobenthos and that seems right due to many reasons. Still, in such a case, the same criterion should be applied to meiobenthos. Therefore, it seems necessary to abandon the procedure of 1.00 mm sieve washing and classify as meiobenthos all organisms considered permanent meiobenthos regardless of their size. As far as temporary meiobenthos is concerned if the organisms could theoretically pass through a 1.00 mm sieve, they should be classified as meiobenthos. The size criteria smaller than 1.00 mm for meiobenthos seem to be proper for sorting particular size groups of meiobenthos but not as the upper size limit for the entire group. A propose of standardisation of the definition and isolating procedures shown on Fig.3. The standardisation of methods and criterion could constitute a new direction in ecohydrological monitoring and evolution of reservoirs, rivers and seas using a group of meiobenthos as a bioindex, in particular of MeioEco method (Wojtasik 2013 a, b).

References

  • Athersuch, J., Horne, D.J. and Whittaker, J.E. 1989. Marine and brackish water ostracods (Superfamilies Cypridacea and Cytheracea). In: Synopsis of the British Fauna (eds. Kermack, D.M., Barnes, R.S.K.). New Series 43. Brill, Leiden.
  • Barton, D.R. and Anholt, B. 1997. The macrobenthos of Lake Ontario during 1964 to 1966, and subsequent changes in the deepwater community. Aquatic Sci. 59:158-175.
  • Bick, A. and Arlt, G. 2005. Intertidal and subtidal soft-bottom macro- and meiofauna of the Kongsfjord (Spitsbergen). Polar Biology 28:550-557.
  • Brandt, A., De Broyer, C., De Mesel, I., Ellingsen, K.E., Gooday, A.J., Hilbig, B., Linse, K., Thomson, M.R.A. and Tyler, P.A. 2007. The biodiversity of the deep Southern Ocean benthos. Philosophical Transactions of the Royal Society 362:39-66.
  • Bronstein Z.S. 1947. Ostracoda presnych vod. Fauna SSSR. Moskva – Leningrad, 2, 1.
  • Chainho, P., Costa, J.L., Chaves, M.L., Dauer, D.M. and Costa, M.J. 2007. Influence of seasonal variability in benthic invertebrate community structure on the use of biotic indices to assess the ecological status of a Portuguese estuary. Marine Pollution Bull. 54:1586-1597.
  • Clarke, K.R. and Gorley, R.N. 2006. PRIMER v6: User Manual/Tutorial. PRIMER-E, Plymouth.
  • Clarke, R.T., Wright, J.F. and Furse, M.T. 2003. RIVPACS models for predicting the expected macroinvertebrates fauna and assessing the ecological quality of rivers. Ecol. Modeling 160:219-233.
  • Coull, B.C. 1970. Shallow Water Meiobenthos of the Bermuda Platform. Oecologia (Berl.), 4:325-357.
  • Czerniawska-Kusza, I. 2005. Comparing modifield biological monitoring working party score system and several biological indices based on macroinvertebrates for water quality assessment. Limnologica 35:169-176.
  • Delorme, L.D. 1970. Freshwater ostracodes of Canada. Part III. Family Candonidae. Canadian Journal of Zoology, 48:1099-1127.
  • Dussart, B. 1967. Les Copépodes des eaux continentals. Tome I: Calanoïdes et Harpacticoïdes. Editions N. BOUBÉE and Cie.
  • Dussart, B. 1969. Les Copépodes des eaux continentals. Tome II: Cyclopoïdes et Biologie. Editions N. BOUBÉE and Cie.
  • Dye, A.H. 2005. Meiobenthos in intermittently open/closed coastal lakes in New South Wales: spatial and temporal patterns in densities of major taxa. Marine and Freswater Res., 56 (8):1055-1067.
  • Feder, H.M., Jewett, S.C. and Blanchard, A.L. 2007. Southeastern Chukchi Sea (Alaska) macrobenthos. Polar Biol., 30:261-275.
  • Floresey, J.J. and Aguirre, A.L.I. 2003. Abundance and first record of benthic macroinvertebrates in Lake Metztitlan, Hidalgo, Mexico. Hydrobiologica 13(2):137-144.
  • Flößner, D. 1972. Krebstiere, Crustacea. Kiemen- und Blattfüßer, Branchiopoda Fischläuse, Branchiura. Jena.
  • Da Fonseˆca-Genevois, V., Somerfield, P.J., Baeta Neves, M.H., Coutinho, R. and Moens, T. 2006. Colonization and early succession on artificial hard substrata by meiofauna. Marine Biol. 148:1039-1050.
  • Gaston, G.R., Bartlett, J.H., McAllister, A.P. and Heard, R.W. 1996. Biomass Variations of Estuarine Macrobenthos Preserved in Ethanol and Formalin. Estuaries 19, 3:674-679.
  • Gal’tsova, V.V., Kulangieva, L.V. and Pogrbov, V.B. 2004. Meiobenthos of the Former Nuclear Test Area and Nuclear Waste Disposal Grounds around the Novaya Zemlya Archipelago (Barents and Kara Seas). Russian J. Marine Biology 30, 4:231–240.
  • da Fonseˆca-Genevois V., Somerfield, P.J., Neves, M.H.B., Coutinho, R. and Moens, T. 2006. Colonization and early succession on artificial hard substrata by meiofauna. Marine Biology, 148:1039-1050.
  • Giere, O. 1993. Meiobenthology, the Microscopic Fauna in Aquatic Sediments. Springer-Verlag, Berlin Heidleberg.
  • Guerrini, A., Colangelo, M.A. and Ceccherelli, V.U. 1998. Recolonization patterns of meiobenthic communities in brackish vegetated and unvegetated habitats after induced hypoxia/anoxia. Hydrobiologia 375/376:73-87.
  • Hawkes, H.A. 1979. Invertebrates as indicators of river water quality. In A. James and L. Evison [eds.], Biological indicators of water quality (Eds..). J. Willey and Sons, Chichester.
  • Houston, K.A., Haedrich, R.I. 1984. Abundance and biomass of macrobenthos in the vicinity of Carson Submarine Canyon, northwest Atlantic Ocean. Marine Biol., 82:301-305.
  • Huys, R., Gee, J.M., Moore, C.G. and Hamond, R. 1996. Marine and Brackish Water Harpacticoid Copepods, Part 1. The Linnean Society of London and The Estuarine and Coastal Sciences Association by Field Studies Council.
  • Kröncke, I. 1994. Macrobenthos composition, abundance and biomass in the Arctic Ocean along a transect between Svalbard and the macarov Basin. Polar Biology 14:519-529.
  • Kurashov, E.A. 2002. The role of meiobenthos in lake ecosystems. Aquatic Ecol. 36:447-463.
  • Lang, K. 1948. Monographie der Harpacticiden. Håkan Ohlssons Boktryckeri, Lund (Sweden).
  • Leunda, P.M., Oscoz, J., Miranda, R. and Arino, A.H. 2009. Longitundinal and seasonal variation of the benthic macroinvertebrate community and biotic indices in an undisturbed Pyrenean river. Ecol. Indicators:52-63.
  • Loeblich, AR.. and Tappan, H. 1964. Sarcodina-chiefly “Thecamoebians” and Foraminiferida. In: Treatise on Invertebrate Paleontology Part C, Protista 2. (ed. Moore, R.C.) Geological Society of America and University of Kansas Press, Lawrence, Kansas.
  • Murray, J. 2006. Ecology and Applications of Benthic Foraminifera. Cambridge University Press.
  • De Pauw, N. and Vanhooren, G. 1983. Method for biological water quality assessment of watercourses in Belgium, Hydrobiologia 100 (1):153-168.
  • Pfannkuche, O. and Thiel, H. 1988. Sample Processing. p. 134-145. In R. P. Higgins and H. Thiel [eds.], Introduction to the Study of Meiofauna. Smithsonian Institution Press Washington D.C. London.
  • Plinski, M. 2007. The biology of marine organisms (Biologia organizmów morskich). Gdansk University Press.
  • Radziejewska, T., Gruszka, P. and Rokicka-Praxmajer, J. 2006. A home away from home: a meiobenthic assemblage in a ship’s ballast water tank sediment. Oceanologia 48 (S):259-265.
  • Reise, K. 1979. Moderate predation on meiofauna by the mcrobenthos of the Wadden Sea. Helgolander wiss. Meeresunters 32:453-465.
  • Rybak, J. I. and Błędzki, L. A. 2005. Copepoda-Cyclopoida. The key for identification. (Widłonogi, Copepoda: Cyclopoida, Klucz do oznaczania). Biblioteka Monitoringu Środowiska, Inspekcja Ochrony Środowiska, Warszawa.
  • Rylov, V.M. 1948. Cyclopoida presnych vod. Fauna SSSR. T3. Izd. Akad. Nauk. Moskva-Leningrad.
  • Sars, G. O. 1903-1911. An account of the Crustacea of Norway with short descriptions and figures of all the species. Copepoda Harpacticoida. Bergen Museum, Bergen.
  • Särkkä, J. 1992. Lacustrine profundal meiobenthos as an environmental indicator. Hydrobiologia, 243/244:333-340.
  • Schizas, N.V. and Shirley, T.C. 1996. Seasonal changes in structure of Alascan intertidal meiofaunal assemblages. Marine Ecol. Progress Ser. 133:115-124.
  • Simboura, N. and Zenetos, A. 2002. Benthic indicators to use in Ecological Quality classification of Mediterranean soft bottom marine ecosystems, including a new Biotic Index. Mediterranean Marine Sci., 3/2:77-111.
  • Soltwedel, T. 1997. Meiobenthos distribution pattern in the tropical East Atlantic: indication
  • for fractionated sedimentation of organic matter to the sea floor? Marine Biology 129:747-756.
  • Sommerfield, P.J. and Warwick, R.M. 1996. Meiofauna in marine pollution monitoring programmes. Ministry of Agriculture, Fisheries and Food directorate of Fisheries Reasearch.
  • Szymelfenig, M., Kwaśniewski, S. and Węsławski, J.M. 1995. Intertidal zone of Svalbard 2. Meiobenthos den sity and occurrence. Polar Biology 15:137-141.
  • Sywula, T. 1974. Małżoraczki (Ostracoda). PWN, Warszawa – Poznań.
  • Wiśniewska (Wojtasik), B. 1997. A new method of segregation of Copepoda (Crustacea) from bottom sediments. Proc. of 24th Polar Symposium, Polish Polar Studies:319-320.
  • Wiśniewska (Wojtasik), B. 2003. The method of segregation of small solid bodies, particularly death meiobenthic organisms, from sediments: sandy, muddy and sandy-muddy (Sposób segregacji drobnych ciał stałych, w szczególności martwych organizmów meiobentosowych, z osadów piaszczystych, mulistych lub mulisto-piaszczystych). Patent No.185451, Polish Patent Office.
  • Wojtasik B. 2009. Evaluation of the stage of development of the littoral of Czorsztyński and Sromowiecki reservoirs (Pieniny Mountains, Poland) on the basis of analyses of meiobenthos assemblages. Ecohydrology and Hydrobiology 9, 2-4:149-157.
  • Wojtasik B. 2013 a. Clumping of meiobenthos organisms for application in the unified appraisal system of the ecological condition of water reservoirs and rivers, in particular bottom sludges and for making maps of ecological state (Zgrupowanie meiobentosu do zastosowania w ujednoliconym systemie oceny stanu ekologicznego zbiorników wodnych i rzek, w szczególności osadów dennych oraz do zastosowania w tworzeniu map stanu ekologicznego). Application No. P.406458, Polish Patent Office.
  • Wojtasik B. 2013 b. Ecological condition of small water reservoirs of Wdzydze Landscape Park (Northern Poland) based on meiobenthos assemblages analyzes. TEKA Komisji Ochrony I Kształtowania Środowiska – OL PAN, 10: 504-514.
  • Yamamuro, M. 2000. Abundance and size distribution of sublittoral meiobenthos along estuarine salinity gradients. J. Marine Systems 26:135-143.
  • Ye, S., Gao, S., Pan, Y., Yang, J. and Li, S. 2005. Automatic separation system for marine meiobenthos based on laser-induced fluorescence technology. J. Zhenjang Univ. Sci., 6B (6):535-539.
  • Żmudziński, L. 1997. Hydrobiology, living in fresh and marine water. (Hydrobiologia, życie wód słodkich i morskich). Wydawnictwo WSP Słupsk.
  • Żmudziński, L., Kornijow, R., Bolałek, J., Górniak, A., Olańczuk-Neyman, K., Pęczalska, A. and Korzeniewski, K. 2002. Hydrobiology dictionary. (Słownik hydrobiologiczny). PWN Warszawa.

Table 1. Meiobenthos – a size criterion,

MEIOBENTHOS


Min size [mm]


Max size [mm]

Authors

Retained on a sieve 0.1


Bick & Ardt (2005)

0.032

1.0

Brandt et al. (2007)

0.062

0.5

Coull (1970)

0.1

1.0

Encyclopedia Britannica (2008)

0.1

2.0

Gal’tsova et al. 2004

0.044

0.5

Da Fonseˆca-Genevois et al. (2006)

Retained on a sieve 0.042 (0.063) or to deep-sea samples 0.031

Pass through a sieve 0.5 (1.0)

Giere (1993)

Retained on a sieve 0.052

Pass through a sieve 1.0

Guerrini et al. (1998)

0.032-0.063

0.5-1.0

http://www.marbef.org/projects/

Greater dimension than or equal to 0.1 mm

shortest dimension is less than 0.5 mm

http://www.sealifebase.org/Glossary

Retained on a sieve 0.038

Pass through a sieve 1.0

Kotwicki et al. (2004)

0.3 (body length),

in procedure a sieve 0.08

Up to 4.0 (body length)

Kurashov (2002)

Retained on a sieve 0.042

Pass through a sieve 1.0

Pfannkuche & Thiel (1988)

0.2

2.0

Plinski (2007)

Equipment to collected samples with mesh gauze 0.04

Pass through a sieve 0.5

Reise (1979)

Retained on a sieve 0.063 or 0.045

Pass through a sieve 0.5

Schizas & Shirley (1996)


Pass through a sieve 0.53

Silva & Williams (2005)

Retained on a sieve 0.063

Pass through a sieve 0.5

Sommerfield & Warwick (1996)


Pass through the sieve 1.0

Szymelfenig et al. (1995)

Retained on a sieve 0.032

Pass through a sieve 0.25

Ye et al. (2005)

Retained on a sieve +/- 0.04

pass through sieve about +/- 1.0

Żmudziński (1997)


+/- 0.04


Smaller than 2.0, pass through a sieve about 1.0

Żmudziński et al. (2002)


Table 2. Macrobenthos – a size criterion of inferior border


MACROBENTHOS

Min size [mm]


Author

Samples washed through a aperture sieve 0.6 (sometimes with aid of a mechanical-hydraulic elutriator), analyzed remaining animals. For some animals used a sieve 0.153

Barton & Anholt (1997)

Retained on a sieve 0.5

Bick & Ardt (2005)

Retained on a sieve 1.0

Feder et al. (2007)

> 0.5

Hawke (1979)

Retained on a sieve 0.52

Houston & Haedrich (1984)

Retained on a sieve 0.5 (juveniles - retained on a sieve 0.25)

Reise (1979)

Retained on a sieve 0.5 or 1.0

Wlodarska-Kowalczuk et al. (1998)

Retained on a sieve 0.4-1.0

Żmudziński (1997)

Fig.1. Different definitions and practical criterion for meio- and macrobenthos analysis (describe in text)

Fig.1. Different definitions and practical criterion for meio- and macrobenthos analysis (describe in text)

Fig.2. A result of used common procedures for collected meio- and macrobenthos

Fig.2. A result of used common procedures for collected meio- and macrobenthos

Fig.3. A propose of standardization of the definition and collected procedures for meio- and macrobenthos

Fig.3. A propose of standardization of the definition and collected procedures for meio- and macrobenthos

Fig. 4. The criterion used in MeioEco analysis

Fig. 4. The criterion used in MeioEco analysis

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