bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fidelity of thermophilic blue‐green algae to hot spring habitats1
Authors: Jackson John E. , Castenholz Richard W. 
Published: March 2010

Inocula of river water and sediment from the Yellowstone Plateau (Wyoming) and the Willamette Valley (Oregon) were incubated in photoautotrophic medium at 14, 35, and 45°C. Many blue‐green algal species developed at 35°C with inocula from numerous habitats. The 45°C temperature promoted the growth of blue‐green algae in samples taken downstream from a source of hot spring or possibly heated industrial waters, but not in samples from pristine waters above hot spring discharges. Most of the 45° enrichments also grew when the culture temperature was raised to 50 and 55°C.The hot spring origins of certain species were determined by their known occurrence in nearby hot springs and by the decrease in cell density with distance downstream from hot spring influents. The dilution with time and distance was partially a result of death, since tests indicated the lethal effect of light on these cells in cold river water. Nevertheless, hot spring cells were still recoverable from 2‐liter water samples 20–30 km from the point of input and occasionally at distances of over 100 km.Samples from waters of Everglades National Park (which reach 35–40°C) also contained several species of blue‐greens capable of growth at 45 and 50°C.Thus thermophilic blue‐green algae that have a growth temperature optimum of over 45°C have a high fidelity to hot spring habitats (or artificially heated waters) in temperate or colder climates, but maintenance populations of some species may become established elsewhere in warmer areas.
Horizontal distribution of planktonic diatoms in Green Bay, mid‐July 19701
Authors: Holland Ruth E. , Claflin Larry W. 
Published: March 2010

A synoptic survey of Green Bay was undertaken in mid‐July 1970 to determine the horizontal distribution of major species of planktonic diatoms.Principal component analyses of R‐correlation and covariance matrices, and four methods of factor analysis described a general bipolar axis which grouped Melosira granulata, Stephanodiscus spp., Cyclotella meneghiniana, and Stephanodiscus niagarae at one pole and Fragilaria crotonensis, Asterionella formosa, Tabellaria flocculosa, and Cyclotella comta at the opposite pole.Cluster analysis of diatoms defined one major group, which predominated in the extreme southern part of the bay, as certain centric species plus the araphid Fragilaria capucina. Two other groups, consisting primarily of other araphids and species of the genus Cyclotella, characterized the rest of the bay.Cluster analysis of 68 stations, based on distribution of diatoms, divided the bay into three major areas: extreme southern Green Bay, southern and eastern Green Bay, and northern and western Green Bay.
Nitrogen fixation and uptake of combined nitrogenous nutrients by Oscillatoria (Trichodesmium) thiebautii in the western Sargasso Sea1
Authors: Carpenter Edward J. , McCarthy James J. 
Published: March 2010

In the western Sargasso Sea in early autumn the standing crop of Oscillatoria thiebautii at nine stations averaged 640 × 105 cells m−2 with a maximum population of 11.8 × 105 cells m−3 at 25 m. Population density at 175 m averaged only 6% of that at 25 m. N2 fixation was greatest at 1‐m depth, 0.069 pg cell−1 h−1, and at 50 m decreased to 9% of that at 1 m. Highest recorded N2 fixation, 0.20 pg cell−1 h−1, was at the southernmost station. Average N2 fixed per square meter of sea surface in the upper 50 m was 2.0 µg N m−2 h−1. When compared with other N inputs to the surface waters of the western Sargasso Sea, N2 fixation by Oscillatoria seems negligible.Results of 15N‐labeled NH4+, NO3−, and urea uptake experiments indicate that O. thiebautii is barely able to utilize these nutrients at the concentrations present in the euphotic zone. Doubling times (Td) for cellular nitrogen by N2 fixation and NH4+ uptake together are in the order of 40 to 110 days. An uptake curve for NH4+ yielded a K. of 6.7 µg‐atoms N liter−1, a value about an order of magnitude greater than that found for other open‐ocean phytoplankters.We were unable to isolate any N2‐fixing bacteria from O. thiebautii.
The geochemical cycle of arsenic in Lake Washington and its relation to other elements1
Authors: Crecelius Eric A. 
Published: March 2010

Abnormally high arsenic concentrations (> 200 ppm dry wt) in the surface sediments of Lake Washington are attributed to atmospheric input of partially soluble arsenic‐rich dust from a copper smelter 35 km upwind and removal of dissolved As from the lake water by bacteria or an inorganic reaction.The suspended matter in the deeper lake water contains 9% iron, 8% manganese, and 350 ppm arsenic. Cores dated by 210Pb indicate that As levels began to increase in the sediments when the smelter began operation in 1890.An arsenic budget for the lake shows equal supplies from the atmosphere and from rivers, and removal by outflowing water (45%) and by accumulation in the sediments (55%). A similar cycle was observed for antimony which is released by the smelter in much smaller amounts than arsenic.About two‐thirds of the As in rain and lake water was in the form of arsenate; however, in the interstitial water 55% of the dissolved As was present as arsenite and a few percent as dimethylarsinic acid.
Nitrogen fixation associated with the marine macroalga Codium fragile1
Authors: Head William D. , Carpenter Edward J. 
Published: March 2010

Nitrogen fixation at rates of up to 7.3 µg N2 fixed g dry wt−1 h−1 is associated with the marine macroalga Codium fragile. A bacterium, identified as an Azotobacter, isolated from Codium, is capable of fixing atmospheric nitrogen in pure culture under aerobic conditions. Scanning electron micrographs showed dense populations of rod‐shaped bacteria, presumed to be Azotobacter, on the surface of Codium.When Codium photosynthesis is decreased by light shading, N2 fixation drops proportionally, suggesting that fixation is coupled to the release of dissolved compounds by Codium. Addition of glucose to seawater increases N2 fixation, indicating that the agent of fixation is a heterotroph.In a field survey, an inverse relationship was found between N2 fixation and the concentration of combined N compounds in seawater. At total available N (NO2−, NO3−, NH4+, urea) concentrations greater than 10 µg‐atoms liter−1, no fixation was associated with Codium. At Nobska Beach the total nitrogen input through N2 fixation in summer was 2.0 mg m−2 day−1 for water columns ranging between 1 and 3 m, and 0.47 in the 3–5‐m stratum.
The rate of mucus production by corals and its assimilation by the coral reef copepod Acartia negligens1
Authors: Richman Sumner , Loya Y. , Sloboclkin Lawrence B. 
Published: March 2010

The secretion of mucus by eight species of scleractinian corals was measured in situ at the Red Sea reef in Eilat, Israel. Selected coral heads were covered with plastic bags and the total organic matter collected after 24 h was determined. The rate of mucus production by massive forms was significantly greater than that by hemispherical or branched species, supporting the suggestion that the massive species use mucus secretion as a mechanism to prevent burial in heavy sedimentation areas on this reef.Overall mucus production results in about 51 mg of particulate organic production m−3 day−1. Laboratory feeding experiments and assimilation measurements with Acartia negligens feeding on radioactive mucus indicate that the zooplankters can assimilate up to 50% of the organic matter of the mucus. Calorific determinations show this material to contain 5.2 ± 0.13 cal mg−1 ash‐free dry weight.
Burial of oscillaxanthin in the sediment of Lake Washington1
Authors: Griffiths Mary , Edmondson W. T. 
Published: March 2010

The distribution of oscillaxanthin in new cores is different from that of cores taken earlier from the same regions. The vertical distribution of oscillaxanthin in six recent cores was qualitatively similar, showing low surface values and three maxima; quantitatively they varied, depending largely upon location, both in total oscillaxanthin (17.00 to 56.16 µg cm−2), and in the depth below which none was found (10.5 to 20.5 cm). Cores taken in 1967 had maxima in the surface centimeter and at mean depths of 3.5 cm and 7.5 cm, whereas 1972 cores had very little in the top 4 cm, and the three maxima had moved down to mean depths of 5.45 cm, 7.85 cm, and 10.35 cm. The present paucity of surface oscillaxanthin reflects the diminution of Oscillatoria in the lake resulting from the diversion of sewage.On the basis of the changes in positions of the shallow maxima it appears that the top 4.95 cm of the sediment in the new cores was deposited in 5.5 years, between 1967 and 1972. However, owing to compaction of the underlying sediment only 2.85 cm was added to the total depth of sediment, giving a net annual accumulation rate of 5.2 mm.
Primary production, standing stock, and export of organic matter in a Mohave Desert thermal stream1
Authors: Naiman Robert J. 
Published: March 2010

The water of a thermal artesian stream (Tecopa Bore) in the Mohave Desert near Death Valley, California, issues from the ground at 47.5°C and cools 8–12°C before leaving a study area 300 m long. Growth occurs year round because of the high water temperature. Pupfish are the dominant herbivores; acquatic invertebrates are rare.The 11,065 kcal m−2 annual input of energy to the biological system is totally accounted for by autochthonous primary production. About 718 kcal m−2 of organic matter is stored within the system in the form of algal mats and detritus and has a turnover time of about 23 days. The bulk of the annual primary production (81%) is channeled into respiration and decomposers; 9% is lost as dissolved organic carbon and 4% as drift of particulate organic matter. Pupfish (Cyprinodon nevadensis amargosae) feed on algae and detritus, ingesting 17% (1,878 kcal m−2 yr−1) of the annual primary production, of which 119 kcal m−2 yr−1 is deposited in growth.
Hamilton Harbor: Periodicities of the physicochemical process
Authors: Palmer Mew D. , Poulton Donald J. 
Published: March 2010

The dynamics of water motion in the Burlington Ship Canal and Hamilton Harbor at the western end of Lake Ontario have been studied with digitally recording meters for current, pH, O2, and conductivity. Water movements and chemistry were strongly influenced by lake and harbor oscillations which produced temporary displacements of the thermocline in both the harbor and canal due to internal waves, along with complex flow regimes including two‐ and three‐layer systems in the canal.Mean mass exchanges in the ship canal were 11 × 104 kg s−1 in each direction. This mass exchange is important in maintaining harbor water quality and providing the necessary dissolved oxygen.
A free vehicle for measuring benthic community metabolism1
Authors: Smith K. L. , Clifford C. H. , Eliason A. H. , Walden B. , Rowe G. T. , Teal J. M. 
Published: March 2010

A free vehicle respirometer (FVR) which measures the oxygen consumption of benthic communities in situ to abyssal depths consists of a structural aluminum tripod supporting a two‐command acoustic release‐transponder, an oxygen monitoring unit, a glass sphere flotation array, and a time lapse camera system. An acoustic signal actuates the first command mode. This releases the oxygen monitoring unit. Settlement is monitored by the camera system. After measurements lasting 1 to 5 days, the second acoustic command releases the descent weight, and the free vehicle is brought to the surface by the flotation array and recovered.Preliminary results obtained with the FVR at 5,200 in in the northwest Atlantic suggest that benthic community respiration decreases three orders of magnitude from values measured at shallow shelf depths.
Particle‐size modification by two size classes of the estuarine copepod Acartia clausi1,2
Authors: O'Connors Harold B. , Small Lawrence F. , Donaghay Percy L. 
Published: March 2010

Two distinct size classes of Acartia clausi were allowed to graze on two different‐sized species of the chain‐forming diatom Thalassiosira. Both copepod size classes dismembered the larger T. gravida chains, producing a high frequency of smaller particles when T. gravida was in high concentrations. In low particle concentrations of T. gravida, the production of small particles was obscured by ingestion. Some particle dismembering might have occurred with the smaller T. nordenskioldii, but the effect also was masked by ingestion. Such particle modification might require a re‐examination of past grazing data.Particle volume ingestion was plotted as a function of particle volume concentration. At high particle densities, both large and small A. clausi could ingest greater volumes of the large T. gravida particles than the smaller T. nordenskioldii particles. At low particle volume densities, both size classes of copepod ingested similar volumes of both diatoms. Large A. clausi ingested greater food volume than small A. clausi, except at the very lowest food volume density (where ingestion was similar). Great variability in the ingestion data occurred as a result of copepod collections in different seasons of different years, and the use of single grazing coefficients is discussed in the light of this variability.
An analysis of the horizontal regime of denitrification in the eastern tropical North Pacific1
Authors: Codispoti L. A. , Richards F. A. 
Published: March 2010

A method using isentropic analysis to estimate nitrate removals by denitrification in the oxygen deficient waters of the eastern tropical North Pacific agreed reasonably well with a technique based on vertical distributions. Dynamic computations permitted an estimate of the horizontal advective transport of these nitrate deficits out of the study region; such transport was a large fraction of the total, indicating that horizontal processes are important.The horizontal transports used in combination with estimates for vertical losses and horizontal diffusive losses yielded a denitrification rate of ⋍2 × 1013 g N yr‒1 for the portion of the eastern tropical North Pacific east of ⋍112°W. This value was in good agreement with estimates based on the application of respiration rates to the appropriate volumes of oxygen deficient water and with an estimate based on a vertical model.
The relationship between the diurnal movements of some of the zooplankton and the sardine Limnothrissa miodon in Lake Kariba, Rhodesia1
Authors: Begg G. W. 
Published: March 2010

The numbers of zooplankton at the surface in the open waters of Lake Kariba increased at night. Of the dominant species, the most extensive migrations were shown by adults of Mesocyclops leuckartii; their nauplii did not show any distinct diurnal movements. Bosmina longirostris exhibited similar, but lesser, movements. Keratella tropica, Keratella cochlearis, and Trichocerca chattoni remained more or less static in the epilimnion throughout the study.For some months after turnover, certain zooplankters move from the floor of the lake to the surface (60 m) each day. When temperature stratification in the monomictic lake intensifies and the hypolimnion becomes devoid of oxygen, these migrations are limited to the depth of the thermocline.These movements are similar to those of the Tanganyika sardine Limnothrissa miodon.
Chemical and biological characteristics of a water column in Lake Tahoe1
Authors: Holm‐Hamen O. , Goldman C. R. , Richards R. , Williams P. M. 
Published: March 2010

A central station in Lake Tahoe has been sampled from the surface to 400 m at four times of year for measurement of phytoplankton biomass; particulate and dissolved organic carbon, nitrogen, and phosphorus; inorganic nutrients; primary productivity; and light, temperature, and oxygen.The gradients observed in distribution of dissolved and particulate material from the surface to 400 m did not vary greatly from summer to winter, even though the water temperature at the February sampling time was almost isothermal. When the water in Tahoe undergoes a winter overturn, biological activity in the lake soon returns the water column to the distinct vertical profiles of inorganic and organic material reported here.
In situ experiments on the dissolved and colloidal state of iron in an acid bog lake1
Authors: Koenings Jeffery P. 
Published: March 2010

A sampler and an analytical and characterization scheme were developed to investigate the chemical and physical state of iron in a highly stained acid bog lake (North Gate Lake). Iron fractions were chemically separated by reactivity to bathophenanthroline (BPN) after specific digestion procedures. Physical separation by anaerobic in situ filtration (450 nm) and in situ dialysis (4.8 nm) resulted in three size classes: particulate, colloidal, and dissolved.Inorganic, nonreactive species of iron [e.g. Fe(OH)3] represent minor amounts of the total iron in North Gate Lake, in contrast to lakes of pH 6–8. In situ radiochemical analyses revealed that colloidal reactive ferric iron predominates in the oxygenated epilimnion, while dialyzable or dissolved ferrous iron increases with depth. Unlike iron, organic matter is present in a nontransient colloidal state. In acid (pH 4–5) bog lakes ferric iron may be colloidal not as an inorganic complex (OH‒) but as reactive Fe3+ by complexation with the colloidal organic acids.After thermally induced mixing with anaerobic waters, ferric iron is reduced and dissolved; however some of the BPN reactive iron remains colloidal, suggesting the presence of a residual ferrous organic complex.
Production of epibenthic salt marsh algae: Light and nutrient limitation1
Authors: Charlene D. Van Raalte , Ivan Valiela , John M. Teal 
Published: March 2010

Epibenthic algal production was measured in Great Sippewissett Marsh, Falmouth, Massachusetts, in plots treated with two levels of a mixed fertilizer and with urea or phosphate. Production, which followed a consistent seasonal pattern with short‐lived peaks in spring and fall, was increased by the highest dosage of mixed fertilizer but not by the other treatments. Fertilization also increased production of the marsh grasses. Algal production at the marsh surface was limited due to shading by the grass canopy. The production rate decreased with increasing biomass of the grasses.To separate the effects of light and nutrients in the treated areas, additional small plots were enriched with three levels of nitrogen (suspected as the limiting nutrient) and provided with three levels of canopy cover cross‐classified to the nitrogen treatments. Shading by the grasses reduced, while fertilization with nitrogen significantly increased, production. When the grasses were dormant, prediction from a model of epibenthic production based on limitation by light compared well with observed measurements. The predicted production rate was higher than that observed during the growing season of the grasses. In the plots receiving the highest doses of mixed fertilizer the added nutrients compensated for the light limitation, since the discrepancy between predicted and observed values was smaller than in the control plots.
Interstitial water chemistry of anoxic Long Island Sound sediments. 1. Dissolved gases1
Authors: Martens Christopher S. , Berner Robert A. 
Published: March 2010

Measurements of dissolved N2, Ar, CH4, and SO42− and salinity and temperature are used to examine the processes controlling their distributions in the interstitial waters of nearshore sediments. Where sulfate reduction is incomplete, dissolved N2 and Ar concentrations in the upper 10–30 cm appear to be controlled by macroinfaunal irrigation activities and vary in accordance with overlying water conditions. Below 30 cm, N2 and Ar concentrations appear to have been last affected by August through October irrigation. In harbor sediments where sulfate reduction is complete at shallow depths, low N2 and Ar concentrations result from in situ stripping by methane bubbles.Methane concentrations remain below about 0.1 mM until about 90% of seawater sulfate is removed. As sulfate concentrations approach zero, methane builds up to bubble saturation. Concave‐up methane depth distributions can be explained by methane consumption following first‐order kinetics in the zone of sulfate reduction. Laboratory jar experiments with natural sediments indicate no methane production during sulfate reduction, in agreement with previous models and distribution studies of sulfate reducing and methanogenic bacteria in lake sediments. Combined laboratory and field results support the hypothesis that methane is produced mainly after sulfate is depleted but is consumed within the sulfate reduction zone as it diffuses upward.
Acetate uptake by aquatic bacterial communities measured by autoradiography and filterable radioactivity1
Authors: Stanley Patricia M. , Staley James T. 
Published: March 2010

In a pulp mill waste aeration lagoon with a high organic content including measurable amounts of acetate, community uptake of acetate followed Michaelis‐Menten kinetics at concentrations of added acetate up to 30 µg ml−1. The measured in situ substrate level, Sn, was <6% to 46% of the K + Sn value calculated from the Michaelis‐Menten equation.Autoradiography was used to determine the uptake kinetics of individual bacterial cells. Two morphologically distinct bacterial types followed Michaelis‐Menten kinetics, but one was at least four times more active in situ. Comparison of several different cell types indicated a minimum uptake activity range of 20‐fold. A few cell types did not absorb acetate. Different cells of the same type showed a 10‐fold range of activity, and the activity per cell did not follow a Poisson distribution.
Effect of benzoate on microbial decomposition of fulvic acids in Tjeukemeer (the Netherlands)
Authors: de Haan H. 
Published: March 2010

The addition of benzoic acid to water from Tjeukemeer stimulated bacterial growth and decreased both the fluorescence and the color of the water, indicating disappearance of fulvic acids. This stimulation of bacterial growth is shown to result most likely from a priming effect of benzoic acid on the slow microbial decomposition of fulvic acid.During growth of an Arthrobacter from the lake on benzoic acid in the presence of fulvic acid, fulvic acid of relatively small molecular size was formed from fulvic acid of relatively large molecular size, suggesting that microbial activity may play a role in the seasonal fluctuations in the molecular size distribution of fulvic acids in Tjeukemeer.
Iron‐rich rhythmically laminated sediments in Lake of the Clouds, northeastern Minnesota1
Authors: Anthony R. S. 
Published: March 2010

Sediments from the deepest part of Lake of the Clouds (31 m) are rhythmically laminated throughout all but the basal part of the column. The laminations can be correlated with events in the lake during the annual cycle. Ferrous iron (maximum 620 ppm) accumulates in a layer of water about 2 m thick in the deepest part of the lake. The laminations form in the sediments only where overlain by this stagnant iron‐rich water. The light‐colored portion of the couplet presumably forms from iron oxides precipitated from partially oxygenated bottom water during fall and spring overturns, the dark layer from organic remains that settle out during summer.Chemical analysis and electron‐microprobe studies reveal a much higher concentration of iron and manganese in the light layers than in the dark. Vivianite [Fe8(PO4)2 · 8H2O] and probably limonite (Fe2O3 · nH2O) occur extensively in nodules throughout the core. Siderite (FeCO3) was identified by X‐ray diffraction. Numerous orange spherical aggregates occur in the light layers. An iron and manganese profile of the sediment column suggests that the most distinct laminae are found where the iron content of the sediment is at least 4%.