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 (hī′pə-lĭm′nē-ŏn′, -ən)
The layer of water in a thermally stratified lake that lies below the thermocline, is noncirculating, and remains perpetually cold.

[hypo- + Greek limnē, lake, pool.]

hy′po·lim·net′ic (-lĭm-nĕt′ĭk), hy′po·lim′ni·al adj.


n, pl -nions or -nia (-nɪə)
(Physical Geography) the lower and colder layer of water in a lake
[C20: from hypo- + Greek limnion, diminutive of limnē lake]


(ˌhaɪ poʊˈlɪm niˌɒn, -ni ən)

n., pl. -ni•a (-ni ə)
(in certain lakes) the layer of water below the thermocline.
[1905–10; hypo- + Greek -limnion, derivative of límnē lake]
hy`po•lim•net′ic (-lɪmˈnɛt ɪk) hy`po•lim′ni•al, adj.
References in periodicals archive ?
One result of the agreement is seen in reductions of total phosphorus (TP) in the water column and a subsequent reduction in hypolimnetic oxygen depletion rate the early 1970s until the early 1990s (Bertram 1993).
Light-trapping of caddisflies at the Thaya (Lower Austria), a river influenced by pulsating hypolimnetic water release.
Tenders are invited for Furnish, Remove 12 Existing And Install 12 New Hypolimnetic Aerator Units
Thienemann, in contrast, emphasized the degree of hypolimnetic oxygen depletion in summer and the benthic organisms associated with eutrophication (Chapra and Dobson, 1981).
Although historically found at high altitudes, didymo can now be found in low-elevation waters where cool hypolimnetic releases below dams seemingly allow didymo to achieve high abundance and bloom frequency (Kirkwood et al.
The release of P from sediments into overlying water during summer hypolimnetic anoxia is a result of complex interaction between biotic and abiotic processes in the water column and sediment (Nowlin et al.
Hypolimnetic weir discharge also contributed to hypoxia at some sites.
Although statistical differences in DO concentrations were not found between the monitored locations, higher hypolimnetic DO concentrations at the center location could be the result of depth and wind action that control vertical mixing (Scheffer 2004), and can be also affected by temperature and temperature gradients.
Fish mortality have been observed in some temperate fish ponds due to mixing or overturn resulting from temperature changes and it was explained that mixing of the large volumes of oxygen deficient hypolimnetic with waters of the epilimnion resulted in dissolved oxygen depletion (Boyd, 1979).
Various methods have been developed to achieve hypolimnetic aeration.
The lake was refilled and two fountains were added at both ends of the lake to adequately aerate the hypolimnetic ("bottom") water.