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Results for “Limnetica”

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3 recordsLinked to original sources
USGS1990

Phytoplankton dynamics in three Rocky Mountain lakes, Colorado, USA

In 1984 and 1985 seasonal changes in phytoplankton were studied in a system of three lakes in Loch Vale, Rocky Mountain National Park, Colorado. Three periods were evident: (1) A spring bloom, during snowmelt, of the planktonic diatom Asterionella formosa , (2) a mid-summer period of minimal algal abundance, and (3) a fall bloom of the blue-green alga Oscillatoria limnetica . Seasonal phytoplankton dynamics in these lakes are controlled partially by the rapid flushing rate during snowmelt and the transport of phytoplankton from the highest lake to the lower lakes by the stream, Icy Brook. During snowmelt, the A. formosa population in the most downstream lake has a net rate of increase of 0.34 d -1 , which is calculated from the flushing rate and from the A. formosa abundance in the inflow from the upstream lake and in the downstream lake. Measurement of photosynthetic rates at different depths during the three periods confirmed the rapid growth of A. formosa during the spring. The decline in A. formosa after snowmelt may be related to grazing by developing zooplankton populations. The possible importance of the seasonal variations in nitrate concentrations were evaluated in situ enrichment experiments. For A. formosa and O. limnetica populations, growth stimulation resulted from 8- or 16-micromolar amendments of calcium nitrate and sulfuric acid, but the reason for this stimulation could not be determined from these experiments.

Colorado↗
USGS2018

Influencia de factores ambientales y biométricos en la capacidad de nado del barbo ibérico (Luciobarbus bocagei Steindachner, 1864), un ciprínido potamódromo endémico de la Península Ibérica

El presente trabajo analiza la capacidad voluntaria de nado del barbo ibérico ( Luciobarbus bocagei Steindachner, 1864) en un canal abierto durante su época de migración, relacionándola con factores ambientales y biométricos. La temperatura del agua, la velocidad de flujo y la longitud del pez fueron los factores de mayor importancia que condicionaron la velocidad de nado de los barbos y su tiempo de fatiga. Dentro del rango de valores estudiado, el barbo ibérico pudo mantener velocidades de nado en sprint (> 15 BL/s) durante 3-10 s, y de 17-117 s en el modo de natación prolongada (7-15 BL/s). Los resultados aportados pueden ser empleados como una herramienta útil para la gestión de sus poblaciones, principalmente para el diseño de pasos para peces. This paper analyzes the volitional swimming capacity of the Iberian barbel ( Luciobarbus bocagei Steindachner, 1864) in an open flume during its migration period, in relation to environmental and biometric factors. Water temperature, flow velocity and fish length were the most important factors which affected the swimming speed of barbels and their fatigue time. Within the range of values studied, the Iberian barbel was able to maintain sprint swim speeds (> 15 BL/s) for 3-10 s, and 17-117 s in prolonged swim mode (7-15 BL/s). The results can be used as a tool for the management of barbel populations, mainly in the design of fishways.

Limnetica↗
USGS2013

Endozoochory of seeds and invertebrates by migratory waterbirds in Oklahoma, USA

Given their abundance and migratory behavior, waterbirds have major potential for dispersing plants and invertebrates within North America, yet their role as vectors remains poorly understood. We investigated the numbers and types of invertebrates and seeds within freshly collected faecal samples (n = 22) of migratory dabbling ducks and shorebirds in November 2008 in two parts of Lake Texoma in southern Oklahoma. Killdeer Charadrius vociferus were transporting a higher number and diversity of both plants and invertebrates than the green-winged teal Anas carolinensis. Ten plant taxa and six invertebrate taxa were identified to at least genus level, although viability was not confirmed for most of these taxa. Bryozoan statoblasts (from four species not previously recorded from Oklahoma) were especially abundant in killdeer faeces, while the ostracod Candona simpsoni was detected as a live adult in torpor in the teal faeces. Cyperaceae and Juncaceae were the most abundant plant families represented and Cyperus strigosus seeds germinated after extraction from killdeer faeces. This snapshot study underlines the importance of waterbirds as vectors of passive dispersal of many organisms and the need for more research in this discipline.

Oklahoma↗