Results for “várzea”

total dissolved solids

Measure of the total concentration of both organic and inorganic, microscopic particles suspended in a given liquid. Usually applied only to freshwater systems and measured using a conductivity or total dissolved solids meter with results expressed in units of mg per unit volume of water (e.g., mg/L) or parts per million (ppm). Soft water with low pH generally has low levels of total dissolved solids whereas harder water with higher pH tends to contain correspondingly increased concentrations. Often abbreviated to TDS.

Used in 2 profiles

wadi

Arabic term used to refer to a valley, stream-bed or other watercourse that only holds water during the rainy season. Often associated with oases and normally applied only in certain Arabic-speaking countries.

Used in 1 profile

water column

Conceptual column representing the vertical section of a water body from surface to substrate.

Used in 124 profiles

Weberian apparatus

Anatomical structure connecting the swim bladder to the inner ear found in members of the fish superorder Ostariophysi. Conveys sound and changes in pressure, and comprises four or five modified vertebrae.

Used in 5 profiles

Weberian ossicle

Any of the modified vertebrae comprising the Weberian apparatus in Ostariophysian fishes, individually named the claustrum, scaphium, intercalarium and tripus.

wet/dry filter

Type of filter normally placed under the aquarium, and often home-made. The basic premise is that water trickles vertically downards through separated compartments containing mechanical and biological filter media with spaces inbetween so that it is also exposed to the air briefly. It then collects in a base chamber or sump from where it is pumped back to the main aquarium. There are many commercial designs available, some of which are more effective than others. Not popular in marine reef aquaria due to the associated accumulation of nitrates as by-product.

white worm

Vernacular name for the annelid worm Enchytraeus albidus Henle, 1937, a species commonly cultured by aquarists for use as live fish food.

Used in 8 profiles

whitebait

Collective term for the young of various fishes, especially herring and sprat. Sometimes used as food for predatory species in aquaria.

Used in 48 profiles

yolk sac

A membranous sac containing yolk attached to the ventral surface of embryos and early larvae in some fishes. Retained for a period post-hatching in those species which form yolk sac larvae.

Used in 221 profiles

yolk sac larva

Post-hatching larval stage occurring in many fish species whereby the yolk sac remains attached to the ventral surface for a period. The larva does not feed normally until the yolk is fully-absorbed.