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


(ˌɛp əˈlɪm niˌɒn, -ən)

n., pl. -ni•a (-ni ə)
(in certain lakes) the layer of water above the thermocline.
[1905–10; epi- + Greek límnion small pond]
ep`i•lim•net′ic (-ˈnɛt ɪk) ep`i•lim′ni•al, adj.
References in periodicals archive ?
The retention potential may be very low for some reservoirs, depending mainly on factors such as dissolved oxygen concentration, light penetration, water velocity, stratification, height of water outlet, and epilimnion and hypolimnion depths.
The ALMS collected continuous in situ time series of key climatological, hydrological, chemical, and biological parameters during both open-water and under-ice seasons and in both the epilimnion and hypolimnion (68[degrees]31'37" N; 133[degrees]30'48" W).
However, during the study period there were occasions of partial mixing in the epilimnion, especially in January and February, but also in July and August, when the surface waters cooled down by 1 [degrees]C to 1.5 [degrees]C.
Fetch determines how deeply wind-driven currents can mix the upper layer of the water column, or epilimnion.
It is revealed in Figure 15 that [Re.sup.1/2.sub.x][C.sub.fx] increases with at epilimnion stage which is known as the highest and warmest layer ([S.sub.t] = 0).
The thermocline layer observed at 3 m to 7 m separates the epilimnion ([approximately equal to] 30.5[degrees]C) and hypolimnion ([approximately equal to] 25.5[degrees]C) at Station 2.
En la LR las diferencias entre el epilimnion y el hipolimnion se hicieron cada vez menores hasta la ruptura de la estratificacion termica durante el otono con la mezcla completa de la columna de agua, lo que genero que las condiciones fisicas y quimicas del lago fueran similares a las determinadas en LM y LTP, durante este periodo.
Factors affecting seasonal pattern in epilimnion zooplankton community in one of the largest man-made lake in Africa (Lake Nasser, Egypt).
The high surface temperatures and the presence of a thermocline prevent mixing between the hypolimnion and epilimnion, leading to differences in parameters such as phytoplankton, pH and DO (Gu and Stefan, 1995).
Whose experience of that glorious strata of warm water would not be enhanced by being able to describe it by its equally glorious proper name, the epilimnion? Our relationship with the landscape is undoubtedly strengthened by our ability to accurately evoke it to others.