Search USGS⌕ Search

SEARCH · Search USGS

Results for “Freshwater Ecology”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
USGS2011

Loss of nitrogenous dissolved organic matter from small lakes

To determine how much organic nitrogen is lost from lakes during winter by natural processes, we collected water in fall and winter from six small lakes (area, 5-822 hectares) and separated organic matter dissolved in the water with n-butanol into three fractions--yellow organic acids, a white precipitate, and aqueous (nonextractable) organic matter. The nitrogen content of each fraction was measured by ultraviolet photolysis. About 25-30% of the yellow acid and white precipitate fractions were lost from the water column in each of the lakes during winter. More than 80% of the organic nitrogen dissolved in the lake water samples was found in the aqueous fraction. We believe the white precipitate is part of the humin material in lake waters because it was relatively insoluble in acidic and alkaline solutions.

Journal of Freshwater Ecology↗
USGS2011

Responses of plankton communities to the introduction of grass carp into some Georgia ponds

Net plankton community structure and numbers were studied in soft-water, acidic ponds containing aquatic macrophytes, after introduction of the herbivorous grass carp ( Ctenopharyngodon idella ). The plankton communities in ponds with grass carp consisted of significantly fewer individuals, genera, and orders than did the communities in control ponds. Expected shifts from desirable to undesirable species of plankton did not occur. These results demonstrate that plankton blooms are not an inevitable result of stocking grass carp, and support the suggestion that macrophytes may be especially significant in nutrient cycling in soft-water, acidic systems.

Georgia↗
USGS2011

Observations on burrowing rates and comments on host specificity in the endangered mussel Lampsilis higginsi

In preliminary laboratory studies, the endangered mussel Lampsitis higginsi was unable to burrow into rocky substrates, but did burrow into substrates comprised of silt, clay, sand, and/or pebble-gravel. Burrowing times were shortest in silt and longest in pebble-gravel. As judged by longevity of glochidial infection, walleye ( Stizostedion vitreum ) and largemouth bass ( Micropterus satrnoides ) may be suitable hosts for the parasitic stage. When glochidia were placed in water without host fish, half had died after 48 hours, and all had died after 72 hours.

Journal of Freshwater Ecology↗
USGS2011

Invertebrate colonization rates in the tailwater of a Kentucky flood-control reservoir

Invertebrate colonization on newly introduced rock substrates was examined from July through October 1982 in the tailwater of Barren River Lake, Kentucky. Chironomidae, the dominant taxon of benthic insects, reached full colonization by day 14. Colonization by Oligochaeta, the other major invertebrate taxon, was not completed by the end of the 95-day period of observation. It may have been delayed because insufficient food (periphyton and detritus) had accumulated on the clean rocks. Rapid recolonization of dewatered substrates may be especially critical for maintaining adequate fish food in tailwaters of flood-control reservoir.

Kentucky↗
USGS2011

Comparison of methods for measuring surface area of submersed aquatic macrophytes

The surface area of submersed macrophytes is often viewed from different perspectives such as substrate for colonization by periphyton, or protective cover for fishes. Consequently, several different methods have been used to measure it. We describe a method for measuring that area with an electronic surface area meter, a device that yields, for large samples of macrophytes, measurements in units of square meters of plant surface area per square meter of bottom. Unpreserved macrophytes, pressed gently between plastic sheets, are passed through the sensing head of the meter, which electronically scans and measures their surface area. The technique is several times faster and more precise than previous methods even for plants with finely dissected leaves.

Journal of Freshwater Ecology↗
USGS1986

Comparison of species composition and richness of fish assemblages in altered and unaltered littoral habitats

Species composition and richness of fish assemblages in altered and unaltered littoral habitats in Lake St. Clair, Michigan, differed between areas. A percid-cyprinid-cyprinodontid assemblage dominated in the unaltered area, Muscamoot Bay, which has a natural shoreline (with almost no alteration due to dredging or bulkheading), high water quality, and high species richness of aquatic macrophytes. A centrarchid assemblage dominated in the altered area, Belvidere Bay, which has a bulkheaded shoreline, many dredged areas, reduced water quality due to inputs of nutrients from a nearby river, and relatively low species richness of aquatic macrophytes. Habitat factors, species richness and abundance of aquatic macrophytes, had the most influence on fish community structure in both areas. The percid-cyprinid-cyprinodontid assemblage was significantly correlated with six species of macrophytes whereas the centrarchid assemblage was significantly correlated with only four. These patterns suggest that preference for diverse habitats was higher, and tolerance to habitat alteration lower, in percid-cyprinid-cyprinodontid assemblages than in centrarchid assemblages.

Michigan↗
USGS1986

Distribution of submersed macrophytes in the St. Clair-Detroit River System, 1978

An extensive survey was conducted in fall 1978 to determine the distribution and abundance of submersed macrophytes through the St. Clair-Detroit River system from Lake Huron to Lake Erie. Submersed macrophytes, representing 19 taxa, were widely distributed in the system, being found on 358 km 2 (30%) of the total 1185 km 2 of substrate surveyed. Of the 19 taxa identified, 8 common taxa were found on 20 to 121 km 2 of substrate. These commonly found taxa, in decreasing order of substrate coverage were Characeae, Vallisneria americana , Najas flexilis , Myriophyllum spicatum , Elodea canadensis , Potamogeton richardsonii , Potamogeton spp. (narrow-leaf forms), and Heteranthera dubia . In general, macrophyte beds of low, medium, and high biomass covered much less area but a higher proportion of the available substrate in the St. Clair and Detroit rivers than in Lake St. Clair.

Journal of Freshwater Ecology↗
USGS1987

The relation between human presence and occurrence of Giardia Cysts in streams in the Sierra Nevada, California

A portable apparatus was used to filter large quantities of water from streams in California's Sierra Nevada. Samples were processed and examined for Giardia spp. Cysts of Giardia were detected in 22 of 49 (44.9 percent) samples collected at sites downstream from areas of high recreational use and in 5 of 29 (17.2 percent) samples collected at sites downstream from areas of low recreational use. These data indicate that intensity of human use may play a significant role or be a useful indicator in Giardia contamination of surface water.

California↗
USGS1989

Seasonal reproductive development of Lampsilis cardium, Amblema plicata plicata, and Potamilus alatus

Adult specimens of three species of freshwater mussels common to the upper Mississippi River were examined histologically to determine seasonal patterns of development in gametogenesis and release of glochidia. Full maturation of gonadal materials in Lampsilis cardium (formerly L. ovata ventricosa ), a long-term breeder, occurred when ambient river temperatures reached 24° to 26°C, between late July and early August. By mid-August, glochidia were present in the marsupia. Glochidia were released from late May through mid-June of the following year once water temperatures reached 20°C. The long-term breeder Potamilus alatus demonstrated full gonadal maturation earlier than seen in L. cardium with reproduction completed by late July (26°C). Glochidia of P. alatus were released over a period similar to that observed for L. cardium , late May through early July of the following year. Fully mature Amblema plicata plicata , a short-term breeder, were collected from late May through early July (18° to 21°C). Glochidia were were released from early June to early August of the same year.

Journal of Freshwater Ecology↗
USGS2011

Effects of fish predation on invertebrates associated with a macrophyte in Lake Onalaska, Wisconsin

We tested the effects of fish predation on the macroinvertebrates associated with Vallisneria americana (Michx) by using enclosure/exclosure experiments in lake Onalaska, Wisconsin. Four treatments were used: open water (cageless) controls, cage-effect controls (partially enclosed cages), exclosures (all fish removed), and enclosures (cages stocked with a known density of bluegills Lepomis macrochirus, Rafinesque). Bluegill predation at the density tested (one 70 mm fish per 0.37m 2 ) did not depress Vallisneria associated invertebrate density. Mean invertebrate abundance and biomass (number and dry weight of invertebrates per g dry plant weight) increased in both exclosures and enclosures relative to open water controls. The most likely explanation is that the cages excluded some vertebrate predator(s) from those two treatments and decreased predation pressure within the cages. Large invertebrates, such as Hyalella azteca, Enallagma sp., Gyraulus sp., and Physa sp., increased in abundance within cages, whereas, small invertebrates such as chironomid larvae decreased in abundance.

Wisconsin↗
USGS2011

Macroinvertebrate communities associated with three aquatic macrophytes (Ceratophyllum demersum, Myriophyllum spicatum, and Vallisneria americana) in Lake Onalaska, Wisconsin

The standing crop and species diversity of macroinvertebrates associated with wild celery (Vallisneria americana), Eurasian watermilfoil (Myriophyllum spicatum), and coontail (Ceratophyllum demersum) were examined in Lake Onalaska, Pool 7 of the upper Mississippi River, during summer 1983. Although Ceratophyllum generally supported the largest invertebrate standing crop (number per g plant dry weight), differences in invertebrate abundance among plant species were not consistent across time. However, the distribution of several taxa were significantly affected by plant species. Hyalella azteca (overall the most abundant species) and Enallagma spp. (the most abundant predator) were consistently most numerous in Ceratophyllum samples and least abundant in Vallisneria samples. Generally, invertebrate community composition differed significantly among plant species throughout the summer.

Wisconsin↗
USGS2011

Improved method for sectioning pectoral spines of catfish for age determination

A modified low-speed saw provided fast and precise sectioning of catfish pectoral spines for use in aging studies. In one hour, 10–15 spines can be sectioned, the sections mounted, and the annuli counted. Two methods commonly used to section ictalurid pectoral spines are (1) acid decalcification, followed by the use of a razor blade or microtome to slice the softened spines, and (2) cutting hard spines with electric saws. Decalcifying methods are time-consuming, and we had difficulty attaining the proper spine consistency for sectioning when we used decalcification techniques. Electric saws with toothed blades tended to obliterate the first-year annulus at the periphery of the central lumen on spines of channel catfish (Scholl 1968). A low speed saw equipped with two, thin parallel diamond blades was used to section fish fin rays and spines (Shepard and Nichy 1984), but drawbacks are that the preparation is time-consuming and the blades tend to warp. We used a low speed saw with a thick (0.3 mm), single blade for slicing the pectoral spines of brown bullheads ( Ictalurus nebulosus ) with fast, accurate and reproducible results. We also successfully sliced the pectoral spines of channel catfish ( Ictalurus punctatus ) and black bullhead ( Ictalurus melas ). The advantages of this method are: (1) spine sections are clear, with uniform thickness and little tissue damage; (2) no time-consuming procedures are necessary; (3) the original spine remains intact for future sectioning; and (4) the thick, single blade does not warp.

Journal of Freshwater Ecology↗
USGS1991

Effects of submersed macrophytes on dissolved oxygen, pH and temperature under different conditions of wind, tide and bed structure

Seasonal data on diurnal dissolved-oxygen concentration (DO), pH, temperature and chlorophyll-a were collected and species composition and vertical structure of macrophyte beds were analyzed in the tidal Potomac River during the 1987 growing season. The relationships among these variables and physical and climatic factors were analyzed. Elevated surface temperatures, DO and pH were found in macrophyte beds in June and August; surface temperatures were also elevated in the dense Hydrilla verticillata dominated bed in October-November after senescence had begun. Bottom DO, pH and temperature were lower than surface values. Bottom temperatures in vegetated sites were highly variable compared with bottom temperatures in unvegetated sites.

Journal of Freshwater Ecology↗
USGS1991

Crayfish ( Orconectes virilis ) feeding on young lake trout ( Salvelinus namaycush ): effect of rock size

In laboratory studies, we quantified predation rates of crayfish ( Orconectes virilis ) on the eggs and sac fry of lake trout ( Salvelinus namaycush ) and a surrogate species, rainbow trout ( Oncorhynchus mvkiss ), dispersed among different sized substrates (bare bottom, gravel, cobble, large rocks). Predation was most severe when no rocks were present. Feeding rate then decreased as the substrate changed from large rocks to cobble to gravel. Crayfish predation rate did not change with prey type—rainbow trout and lake trout eggs or sac fry. Crayfish foraging in large tanks containing cobble averaged about two eggs or sac fry per day. In most instances, crayfish would have little impact on lake trout egg survival. Only in lake trout spawning grounds with relatively low egg densities, large crayfish populations, and cobble or large rock substrate, would crayfish be expected to have some impact on lake trout egg survival.

Journal of Freshwater Ecology↗
USGS1991

Assessment of the sensitivity of Missouri reservoirs to acidification

We used water quality information from 103 Missouri reservoirs to assess their sensitivity to acidification from acidic atmospheric deposition. Total alkalinity less than 20 mg/L or a Calcite Saturation Index (CSI) of 1.0 or greater were the criteria to classify reservoirs as sensitive to acidification. Most of the reservoirs (83 of 103) would be considered circumneutral, hard water systems with high acid neutralizing capacity. Thirteen reservoirs were sensitive to acidification based on alkalinity or CSI. Four reservoirs with both low alkalinity and high CSI are located in southeast Missouri in areas of igneous rock outcroppings or chert deposits in limestone formations. These reservoirs are small (<40 ha) and have limited watersheds (<600 ha) and site-specific edaphic factors that likely determined their water chemistry. Site-specific factors also influenced water chemistry of acid-sensitive reservoirs that were located in regions expected to yield highly buffered water. No reservoir classified as acid-sensitive presently seems affected by acidification.

Journal of Freshwater Ecology↗
USGS1992

Habitat use by larval fishes in backwater lake of the upper Mississippi River

Light traps were used to sample larval fishes in Lawrence Lake (Pool 8, upper Mississippi River) from late May through mid-August 1990. Catches differed considerably between vegetated sites and an adjacent open-water area and were highly variable among vegetated stations. Sunfishes ( Lepomis spp.) dominated the vegetated sites. Brook silversides ( Labidesthes sicculus ), Cyprinidae and gizzard shad ( Dorosoma cepedianum ) dominated catches at the open-water site. There was no difference in fish use of vegetated habitats near and far from the main channel of the Mississippi River. Taxonomic diversity was greatest at stations with emergent vegetation.

Journal of Freshwater Ecology↗
USGS1993

Reproductive characteristics of a population of the washboard mussel Megalonaias nervosa (Rafinesque 1820) in the upper Mississippi River

We examined monthly and age-specific gametogenic development of the washboard mussel, Megalonaias nervosa , from April 1986 to March 1987 in navigation Pool 10 of the upper Mississippi River. We found M. nervosa to be a late tachytictic breeder. Female marsupia contained eggs or glochidia primarily from August (17°C) through October (9°C). Males were mature from July through October. Most females released their glochidia in October. Only one female was gravid in November (3°C). Most mussels were sexually mature at 8 years of age and then had an estimated average size of 68 mm (shell height). Only 8% of individuals ≤ 4 years of age showed any degree of reproductive development, while > 90% of age 5 and older individuals had recognizable reproductive material present. In host specificity studies, we verified three fish species as hosts for the glochidial stage. Green sunfish ( Lepomis cyanellus ), black bullhead ( Ictalurus melas ), and channel catfish ( Ictalurus punctatus ) produced juveniles after 26–28 days at 17°C. White suckers ( Catastomus commersoni ) and yellow perch ( Perca flavescens ) retained glochidia from 23 up to 26 days, but no juveniles were produced. Glochidia remained attached to common carp ( Cyprinus carpio ) and fathead minnows ( Pimephales promelas ) ≤ 3 days. Channel catfish were retested at 12°C and produced juveniles after 56 days.

Journal of Freshwater Ecology↗
USGS1993

Morphometric differentiation of American shad and white sucker eggs from riverine samples

We developed a statistical method to distinguish the large demersal eggs of American shad from those of white sucker in riverine samples using egg morphometric analysis. Eggs were first screened by total diameter in deionized water according to ranges reported in the published literature. Differences in relative yolk diameter between the two species were then determined statistically from known museum sources. Only those eggs with relative yolk diameters greater than two standard deviations below the mean for white sucker eggs were considered to be American shad eggs. The criteria for American shad eggs were total diameter ≥2.3 nm and relative yolk diameter ≤66%. A partial test of the model showed predicted identity to agree with observed identity for 74 out of 75 shad eggs.

Journal of Freshwater Ecology↗