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At least 73 records · Page 4Linked to original sources
USGS2011

The distribution and abundance of a nuisance native alga, Didymosphen Didymosphenia geminata, in streams of Glacier National Park: Climate drivers and management implications

Didymosphenia geminata (didymo) is a freshwater alga native to North America, including Glacier National Park, Montana. It has long been considered a cold-water species, but has recently spread to lower latitudes and warmer waters, and increasingly forms large blooms that cover streambeds. We used a comprehensive monitoring data set from the National Park Service (NPS) and USGS models of stream temperatures to explore the drivers of didymo abundance in Glacier National Park. We estimate that approximately 64% of the stream length in the park contains didymo, with around 5% in a bloom state. Results suggest that didymo abundance likely increased over the study period (2007-2009), with blooms becoming more common. Our models suggest that didymo abundance is positively related to summer stream temperatures and negatively related to total nitrogen and the distance downstream from lakes. Regional climate model simulations indicate that stream temperatures in the park will likely continue to increase over the coming decades, which may increase the extent and severity of didymo blooms. As a result, didymo may be a useful indicator of thermal and hydrological modification associated with climate warming, especially in a relatively pristine system like Glacier where proximate human-related disturbances are absent or reduced. Glacier National Park plays an important role as a sentinel for climate change and associated education across the Rocky Mountain region.

Park Science↗
USGS2011

The distribution and abundance ofa nuisance native alga, Didymosphenia geminata,in streams of Glacier National Park: Climate drivers and management implications

Didymosphenia geminata (didymo) is a freshwater alga native to North America, including Glacier National Park, Montana. It has long been considered a cold-water species, but has recently spread to lower latitudes and warmer waters, and increasingly forms large blooms that cover streambeds. We used a comprehensive monitoring data set from the National Park Service (NPS) and USGS models of stream temperatures to explore the drivers of didymo abundance in Glacier National Park. We estimate that approximately 64% of the stream length in the park contains didymo, with around 5% in a bloom state. Results suggest that didymo abundance likely increased over the study period (2007–2009), with blooms becoming more common. Our models suggest that didymo abundance is positively related to summer stream temperatures and negatively related to total nitrogen and the distance downstream from lakes. Regional climate model simulations indicate that stream temperatures in the park will likely continue to increase over the coming decades, which may increase the extent and severity of didymo blooms. As a result, didymo may be a useful indicator of thermal and hydrological modification associated with climate warming, especially in a relatively pristine system like Glacier where proximate human-related disturbances are absent or reduced. Glacier National Park plays an important role as a sentinel for climate change and associated education across the Rocky Mountain region.

Montana↗
USGS1977

The quantitative determination of chlorophylls A and B from freshwater algae without interference from degradation products

Chlorophyll was efficiently extracted from freshwater algae with dimethyl sulfoxide. The extract was chromatographed on commercially available thin-layer cellulose sheets, 2 percent methanol and 98 percent petroleum ether being used as the solvent. Chlorophylls a and b , and phaeophytins a and b were cleanly separated from each other and other degradation products. No artifacts were formed. Recoveries of chlorophylls a and b were 98 and 96 percent as measured by spectrophotometry or fluorometry.

Journal of Research of the U.S. Geological Survey↗
USGS1976

Liquid scintillation counting of filtered algae in primary production studies

A technique for preparing phytoplankton samples for liquid scintillation counting and standardization has been developed. It consists of digestion of the carbon-14 labeled algae on small, inert filters coupled with a filter standardization and channels ratio method of efficiency determination. The technique is an alternative to many currently used methods which result in two-phase systems whose counting efficiency cannot be easily determined. Although it does not produce a purely homogeneous solution, the proposed technique does allow for a more accurate determination of counting efficiency within the usual range of application in eutrophic or saline water.

Journal of Research of the U.S. Geological Survey↗
USGS2018

Low-dose stimulation of growth of the harmful alga, Prymnesium parvum, by glyphosate and glyphosate-based herbicides

Glyphosate-based herbicides (GBH) are widely used around the globe. While generally toxic to phototrophs, organic phosphorus in glyphosate can become available to glyphosate-resistant phytoplankton and contribute to algal bloom development. Few studies have examined the effects of GBH on growth of eukaryotic microalgae and information for the toxic bloom-forming haptophyte, Prymnesium parvum , is limited. Using a batch-culture system, this study examined the effects on P. parvum growth of a single application of Roundup Weed and Grass Killer Super Concentrate Plus® (Roundup SC), Roundup Weed and Grass Killer Ready-to-Use III® (Roundup RtU), and technical-grade glyphosate at low concentrations [0-1000 μg glyphosate acid equivalent (ae) l -1 ]. Roundup formulations differ in the percent of glyphosate as active ingredient (Roundup SC, ∼50%; Roundup RtU, 2%), allowing indirect evaluation of the influence of inactive ingredients. Roundup SC enhanced exponential growth rate at 10-1000 μg glyphosate ae l -1 , and a positive monotonic association was noted between Roundup SC concentration and early (pre-exponential growth) but not maximum cell density. Glyphosate and both Roundup formulations enhanced growth rate at 100 μg glyphosate l -1 , but only Roundup SC and glyphosate significantly stimulated early and maximum density. This observation suggests the higher concentration of inactive ingredients and other compounds in Roundup RtU partially counteracts glyphosate-dependent growth stimulation. When phosphate concentration was varied while maintaining other conditions constant, addition of Roundup SC and glyphosate at 100 μg l -1 influenced growth more strongly than equivalent changes in phosphate-associated phosphorus. It appears, therefore, that low doses of glyphosate stimulate growth by mechanisms unrelated to the associated small increases in total phosphorus. In conclusion, glyphosate and GBH stimulate P. parvum growth at low, environmentally relevant concentrations. This finding raises concerns about the potential contribution to P. parvum blooms by glyphosate-contaminated runoff or by direct application of GBH to aquatic environments.

Harmful Algae↗
USGS2019

Invasive silver carp may compete with unionid mussels for algae: First experimental evidence

1. Unionid mussels are imperiled throughout the United States, where their global diversity is highest. Silver carp (Hypophthalmichthys molitrix Valenciennes in Cuvier & Valenciennes, 1844), an invasive planktivorous fish, has spread throughout Midwestern rivers and currently threatens the Great Lakes. Because silver carp remove plankton and other particles from the water column, they may compete with mussels for food resources. This would be among the first examples of a direct competitive interaction between fish and mussels. 2. To examine the potential for competition, a 30-d tank experiment was performed with 2-yr old fatmucket mussels (Lampsilis siliquoidea Barnes, 1823) and age-1 silver carp in three treatments: fatmucket only, silver carp only, and fatmucket + silver carp. All tanks were given a commercial algal-based diet daily and dry mass of suspended particles (an estimate of available food) and NH4, NO3, and NO2 concentrations were quantified every 5 d to track food availability and changes in nutrients. Initial and final silver carp total length (mm) and mass (g), and fatmucket length (mm), height (mm), and surface area (mm2) were measured. 3. Survival was 100% over the test duration for both species. Fatmucket grew less in the fatmucket + silver carp treatment, while silver carp growth was low regardless of treatment. Fatmucket also exhibited increased movement in the presence of silver carp. Suspended particles did not differ among treatments. Dissolved nitrogen concentrations were higher in the silver carp treatments, suggesting that silver carp increase nutrient availability in aquatic systems. 4. Overall, the slower growth rates observed in the fatmucket + silver carp treatment compared to the mussel only treatment suggest exploitative competition between invasive planktivorous silver carp and fatmucket and this competition could contribute to additional stress on already imperiled mussels.

Midwest↗
USGS1983

Effect of retorted-oil shale leachate on a blue-green alga (Anabaena flos-aquae)

In the event of the development of the large oil shale reserves of Colorado, Utah, and Wyoming, one of the main environmental concerns will be disposal of retorted-oil shale which will be generated in greater volume than the original volume oI the mined oil shale. Investigators have found that leachates of retorted-oil shale are alkaline and have large concentrations of dissolved solids, molybdenum, boron, and fluoride (STOLLENWERK & RUNNELS 1981). STOLLENWERK & RUNNELS (1981) concluded that drainage from waste shale piles could have deleterious effects on the water quality of streams in northwestern Colorado.

Bulletin of Environmental Contamination and Toxico↗
USGS2013

Calcification rates of the massive coral Siderastrea siderea and crustose coralline algae along the Florida Keys (USA) outer-reef tract

Coral reefs are degrading on a global scale, and rates of reef-organism calcification are predicted to decline due to ocean warming and acidification. Systematic measurements of calcification over space and time are necessary to detect change resulting from environmental stressors. We established a network of calcification monitoring stations at four managed reefs along the outer Florida Keys Reef Tract (FKRT) from Miami to the Dry Tortugas. Eighty colonies (in two sequential sets of 40) of the reef-building coral, Siderastrea siderea , were transplanted to fixed apparatus that allowed repetitive detachment for buoyant weighing every 6 months. Algal-recruitment tiles were also deployed during each weighing interval to measure net calcification of the crustose coralline algal (CCA) community. Coral-calcification rates were an order of magnitude greater than those of CCA. Rates of coral calcification were seasonal (summer calcification was 53% greater than winter), and corals in the Dry Tortugas calcified 48% faster than those at the other three sites. Linear extension rates were also highest in the Dry Tortugas, whereas percent area of the coral skeletons excavated by bioeroding fauna was lowest. The spatial patterns in net coral calcification revealed here correlate well with Holocene reef thickness along the FKRT and, in part, support the “inimical waters hypothesis” proposed by Ginsburg, Hudson, and Shinn almost 50 yrs ago to explain reef development in this region. Due to the homogeneity in coral-calcification rates among the three main Keys sites, we recommend refinement of this hypothesis and suggest that water-quality variables (e.g., carbonate mineral saturation state, dissolved and particulate organic matter, light attenuation) be monitored alongside calcification in future studies. Our results demonstrate that our calcification monitoring network presents a feasible and worthwhile approach to quantifying potential impacts of ocean acidification, warming, and/or deteriorating water quality on the process of calcification.

Florida↗
USGS2015

A chronicle of a killer alga in the west: Ecology, assessment, and management of Prymnesium parvum blooms

Since the mid-1980s, fish-killing blooms of Prymnesium parvum spread throughout the USA. In the south central USA, P. parvum blooms have commonly spanned hundreds of kilometers. There is much evidence that physiological stress brought on by inorganic nutrient limitation enhances toxicity. Other factors influence toxin production as well, such as stress experienced at low salinity and temperature. A better understanding of toxin production by P. parvum remains elusive and the identities and functions of chemicals produced are unclear. This limits our understanding of factors that facilitated the spread of P. parvum blooms. In the south central USA, not only is there evidence that the spread of blooms was controlled, in part, by migration limitation. But there are also observations that suggest changed environmental conditions, primarily salinity, facilitated the spread of blooms. Other factors that might have played a role include altered hydrology and nutrient loading. Changes in water hardness, herbicide use, system pH, and the presence of toxin-resistant and/or P. parvum -inhibiting plankton may also have played a role. Management of P. parvum in natural systems has yet to be attempted, but may be guided by successes achieved in small impoundments and mesocosm experiments that employed various chemical and hydraulic control approaches.

Hydrobiologia↗
USGS2008

Influence of natural dissolved organic carbon on the bioavailability of mercury to a freshwater alga

Bioavailability of mercury (Hg) to Selenastrum capricornutum was assessed in bioassays containing field-collected freshwater of varying dissolved organic carbon (DOC) concentrations. Bioconcentration factor (BCF) was measured using stable isotopes of methylmercury (MeHg) and inorganic Hg(II). BCFs for MeHg in low-DOC lake water were significantly larger than those in mixtures of lake water and high-DOC river water. The BCF for MeHg in rainwater (lowest DOC) was the largest of any treatment. Rainwater and lake water also had larger BCFs for Hg(II) than river water. Moreover, in freshwater collected from several US and Canadian field sites, BCFs for Hg(II) and MeHg were low when DOC concentrations were >5 mg L-1. These results suggest high concentrations of DOC inhibit bioavailability, while low concentrations may provide optimal conditions for algal uptake of Hg. However, variability of BCFs at low DOC indicates that DOC composition or other ligands may determine site-specific bioavailability of Hg.

Environmental Pollution↗
USGS2011

Spectral definition of the macro-algae Ulva curvata in the back-barrier bays of the Eastern Shore of Virginia, USA

We have developed methods to determine the visible (VIS) to near-infrared (NIR) spectral properties of thalli and epiphytes of bloom-forming and green macrophyte Ulva curvata in back-barrier lagoons in Virginia, USA. A 2% increase in NIR thalli reflectance from winter to summer (ca. 9.5%) matched the drop in summer NIR transmittance (ca. 90%). In contrast, summer and winter VIS reflectance (reaching 6%) were nearly identical while winter transmittance (ca. 85%) was 10–20% higher. NIR absorption remained at 5% but VIS absorption increased by 10–20% from winter to summer. Replicate consistency substantiated the high transmittance difference indicating thallus composition changed from summer to winter. Epiphytes increased thallus reflectance (<ca. 4%) and decreased transmittance (<ca. 10%) and exhibited broadband VIS and NIR absorptions in summer and selective peaks in winter. A simulation coupling water extinction with thallus reflectance and transmittance found seven submerged thalli maximized the surface reflectance enhancement (ca. 2.5%).

International Journal of Remote Sensing↗
USGS2011

Flat-plate techniques for measuring reflectance of macro-algae ( Ulva curvata )

We tested the consistency and accuracy of flat-plate spectral measurements (400&ndash;1000 nm) of the marine macrophyte Ulva curvata . With sequential addition of Ulva thallus layers, the reflectance progressively increased from 6% to 9% with six thalli in the visible (VIS) and from 5% to 19% with ten thalli in the near infrared (NIR). This progressive increase was simulated by a mathematical calculation based on an Ulva thallus diffuse reflectance weighted by a transmittance power series. Experimental and simulated reflectance differences that were particularly high in the NIR most likely resulted from residual water and layering structure unevenness in the experimental progression. High spectral overlap existed between fouled and non-fouled Ulva mats and the coexistent lagoon mud in the VIS, whereas in the NIR, spectral contrast was retained but substantially dampened by fouling.

International Journal of Remote Sensing↗
USGS2021

Long-term salinity change and growth of the harmful alga, Prymnesium parvum

Prymnesium parvum is a euryhaline, toxin-producing microalga. Although its abundance in inland waters and growth potential in the laboratory is reduced at high salinity (>20), the ability of inland strains to adjust their growth after long-term residence in high salinity is uncertain. An inland strain of P. parvum maintained at salinity of 5 in modified artificial seawater medium (ASM-5) was subjected to the following treatments over five sequential batch culture rounds: ASM-5 (control); modified ASM at salinity of 30, raised with NaCl; modified ASM at salinity incrementally increased to 30 with NaCl; and Instant Ocean ® at salinity of 30 (IO-30). Exponential growth rate ( r ) was reduced when salinity was increased from 5 to 30 in ASM but returned to control values during the second round. When salinity was incrementally increased, a reduction in r still occurred when salinity reached 25-30. Maximum density was reduced at salinity of 30 in ASM upon abrupt transfer or incremental increase, and compensation did not occur. Growth performance in IO-30 was comparable to control values. In conclusion, (i) long-term compensation for acute inhibitory effects of high salinity occurred for r but not maximum density, (ii) incremental increases in salinity did not prevent growth inhibition, suggesting the existence of a salinity threshold of 25–30 for onset of salinity stress, and (iii) the presence of a seawater-like salt mixture prevented growth inhibition by high salinity. These findings provide new insights on P. parvum 's long-term ability to adjust its growth in environments of different salinity and ionic composition.

Journal of Phycology↗
USGS1995

Removal of algae by the zebra mussel ( Dreissena polymorpha ) population in western Lake Erie: a bioenergetics approach

A bioenergetics model for growth of a zebra mussel ( Dreissena polymorpha ) individual was verified with observations on zebra mussel growth in western Lake Erie. The bioenergetics model was then applied to the zebra mussel population in the western basin of Lake Erie to estimate the removal of phytoplankton by mussels. According to the modeling results, the zebra mussel population consumed 5.0 million tonnes of phytoplankton, while 1.4 million tonnes of phytoplankton was deposited in pseudofeces from the mussels. Thus, a total of 6.4&ensp;&plusmn;&ensp;2.4 million tonnes of phytoplankton was removed from the water column by zebra mussel in western Lake Erie during 1990. Primary production was estimated to be 24.8 million tonnes; therefore, zebra mussel removed the equivalent of 26&ensp;&plusmn;&ensp;10% of the primary production for western Lake Erie.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS1981

Toxicity of Mount St. Helens ash leachate to a blue-green alga

During several periods of volcanic-ash eruption at Mount St. Helens, Wash., (March 30, May 25-26, May 30-June 2, and June 12-13, 1980) strong winds from the north occurred at high altitudes. As a result, the volcanic ash fell some 50 miles to the south in the Bull Run watershed, the principal water-supply source for the metropolitan area of Portland, Oreg. Water samples collected from three stream sites within the watershed were compared with samples collected during the same season in previous years. No detectable changes were noted in chemical characteristics. Precipitation samples collected immediately after the June 12-13 ash fall ranged in specific conductance from 20 to 41 micromhos per centimeter at 25C and in pH from 4.0 to 4.3 pH units. Stream samples collected during the May-June period ranged in specific conductance from 18 to 28 micromhos per centimeter at 25C and in pH from 6.7 to 7.5 pH units. Volcanic-ash samples were collected and analyzed for particle size, chemical composition, and weight. Significant differences in particle size of ash were found in samples from two separate eruptions. (USGS)

Circular↗