bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of environmental factors on phytoplankton growth: Temperature and the interactions of temperature with nutrient limitation1
Authors: Rhee G‐Yull , Gotham Ivan J. 
Published: March 2010

The combined stress of nutrient limitation and suboptimal temperature on growth was studied with turbidostat and chemostat cultures of Scenedesmus sp. and Asterionella formosa. The combined effects were greater than the sum of individual effects and were not multiplicative. In N‐ and P‐limited Scenedesmus sp. and A. formosa the cell (q) of both limiting and nonlimiting nutrients increased with decreasing temperature. At a given temperature cell quotas of limiting nutrients also increased with the growth rate (µ) and followed a saturation function. Higher values of the minimum cell quota (qo) at lower temperatures show that cells require more nutrient with decreasing temperature. The change of qo with temperature varies with the type of limiting nutrient. This change for N and P in Scenedesmus sp. suggests that their optimum ratio, the ratio at which one limitation changes over to the other, is higher at suboptimal temperatures.Cell quotas of nutrient‐sufficient cultures (qm) for C, N, and P and cellular chlorophyll a concentration increased with decreasing temperature. The quota of each nonlimiting nutrient in nutrient‐limited cultures had the same value as qm. The rate of protein synthesis per unit RNA decreased with temperature.The highest apparent maximum N uptake was observed at 15°C for N‐limited Scenedesmus sp. growing at 0.5·d‒1. The optimal growth temperature range, however, was 20°–25°C. The highest apparent maximum P uptake in A. formosa was found at 19°–20°C, when µ = 0.4·d‒1. These temperatures were also optimal for growth.
Thermal tolerance and acclimation of two species of Hydra1
Authors: Schroeder Lauren Alfred , Callaghan William M. 
Published: March 2010

The upper lethal temperature for Hydra pseudoligactis was greater than for Hydra oligactis and increased from 31° to 34°C as the rearing temperature increased from 5° to 27°C. The upper lethal temperature for H. oligactis was constant (26°C) between rearing temperatures of 5° and 21°C. However, when it was reared at 27°C the upper lethal temperature increased to 31°C.The low upper lethal temperature for H. oligactis may exclude it from shallow pond habitats and contribute to the rapid population decline often observed in the epilimnion of temperate lakes.
Summer population fluctuations, feeding, and growth of Hydra in an arctic lake1
Authors: Cuker Benjamin E. , Mozley Samuel C. 
Published: March 2010

During 1977, the population density of Hydra in the rocky littoral community in Toolik Lake, Alaska, increased from June to a maximum in late July or early August, then remained stable or decreased slightly through late August. The summer increase of Hydra corresponded to increases in the availability of copepods and Bosmina (the preferred prey) until late July. Hydra kept at lake temperatures in the laboratory with unlimited prey reproduced fast enough asexually to account for these increases: at 19°C the intrinsic rate of increase (r, biomass) was 0.53 g·g‒1·d‒1, and at 11°C, r = 0.31·d‒1. These rates, much higher than those for other Hydra at comparable temperatures, seem to be a metabolic adaptation to arctic conditions. Failure of the Hydra population to continue to increase while food resources increased in August is attributed to predation by Lymnaea, displacement by epilithic algal growth, endogenously controlled emigration from the rocky littoral, or some combination of these.Hydra appears to be the most important predator on Bosmina. Hydra at densities of 135·m‒2 on the rocky shoals could take 1,620 Bosmina · m‒2·d−1 during late July and early August 1977, about 10% per day consumption of the estimated lake standing crop of Bosmina. This is the first evidence that Hydra plays a major role in controlling a prey population.
Solubilities of gypsum and halite in the Dead Sea and in its mixtures with seawater1
Authors: Katz Amitai , Starinsky Avraham , Taitel‐Goldman Nurit , Beyth Michael 
Published: March 2010

The solubilities of gypsum (CaSO4·2H2O) and halite (NaCl) in aqueous solutions with ionic strengths between 3 and 13 were studied under ambient conditions. Mixtures of Mediterranean seawater and Dead Sea brines, evaporated to various degrees, served as experimental solutions.The practical solubility constant of gypsum [KGsp = (mCa × mSO4) eq] was found to be related to the ionic strength (I) of the solution by the empirical expression
urn:x-wiley:00243590:media:lno19812640709:lno19812640709-math-0001

This relationship was then applied to calculate the degree of saturation with respect to gypsum (DSG) of the present Dead Sea water column.Calculations indicate that the entire Dead Sea water column (ionic strength = 9–10) is saturated or even slightly oversaturated with respect to both minerals studied.
Products of photosynthesis in phytoplankton off the Orinoco River and in the Caribbean Sea1
Authors: Morris I. , Smith A. E. , Glover H. E. 
Published: March 2010

Incorporation of [14C]bicarbonate into the major end‐products of photosynthesis (low molecular weight metabolites, lipid, polysaccharide, and protein) was measured at a number of stations in tropical waters. Stations with highest chlorophyll concentrations showed almost equal synthesis of low molecular weight metabolites, lipid, polysaccharide, and protein. The “oligotrophic” stations showed a greater incorporation into polysaccharide and protein and proportionally less into the other two fractions. Inshore stations also showed higher activities of the photosynthetic carboxylating enzyme, ribulose‐1,5‐bisphosphate carboxylase, in relation to that of the anaplerotic replenishment enzyme, phospho(enol) pyruvate carboxylase.The inshore, high chlorophyll stations were characterized by higher particulate : chlorophyll ratios. However, the polysaccharide and protein contents (normalized to particulate carbon) were not higher in the offshore samples showing high incorporation of 14C into those polymers. Carbon‐specific assimilation rates were greater for total C incorporation than for incorporation into the various polymers. This was most marked when assimilation was measured only over a period in the light.
Oceanography of the eastern Bering Sea ice‐edge zone in spring1
Authors: Alexander V. , Niebauer H. J. 
Published: March 2010

The ice‐edge region of the southeast Bering Sea was studied in terms of the hydrographic regime, phytoplankton biomass, and primary productivity during the springs of 1975 through 1977. The results showed that a phytoplankton bloom occurs at the ice edge just as the spring ice‐decay period begins, and that this accounts for a significant proportion of the annual carbon input over the shallow shelf. The bloom is intensified in time and space by the influence of the ice edge on the physical structure of the water column. Specifically, melting ice seems to increase the stability of the water column, near and under the ice, by lowering the salinity. Frontal structure in salinity and temperature are apparent at the ice edge and are attributed to the melting ice but also, at times, to wind‐driven Ekman‐type upwelling.These data are also related to recent short term (ca. months‐year) climatic fluctuations that seem to control the seasonal position of the ice‐edge zone relative to the shelf break. In “cold” years, the ice edge comes southward to the shelf break and overlies the more nutrient‐rich Alaska Stream/Bering Sea source water. In “warm” years, the ice‐edge zone does not reach this nutrient‐rich water. This may be important to the biology of the ice‐edge ecosystem.
Hydrographic observations and mixing processes in the New York Bight, 1975–1977
Authors: Han Gregory , Niedrauer Terren 
Published: March 2010

A series of 15 hydrographic cruises in the New York Bight over 1975–1977 is described and analyzed. The cruises cover all seasons but focus primarily on spring and summer. Temperature and salinity data show wide seasonal and interannual variability. Each of the three regions—inner bight, midshelf, and outer shelf slope—has distinctive properties and dynamics.The inner bight properties are affected primarily by river flow and wind‐driven flows up the shelf valley which often splits the freshwater surface layer into two plumes, one east and one west of the valley head. The “cold pool” temperature structure on the midshelf is different each year. The water with the lowest recorded temperature (2.58°C) was on the bottom after the thermocline formation in May 1977.Mixing models of the inner bight confirmed previous estimates of residence time as 6.8 days and yielded Kr = 5 × 106 cm2·s−1 with an advective transport component of 1 cm·s−1 to the southwest. A model of the mixing of the lower layer cold pool on the midshelf with onshore, offshore, and upper layer waters yields Kx = 7 × 106 and Kz = 0.1 cm2·s−1 as the on‐offshore horizontal and vertical diffusion coefficients.
A fluid dynamics study of seawater flow through Gelidium nudifrons1
Authors: Anderson S. Miles , Charters A. C. 
Published: March 2010

Gelidium nudifrons, growing in the subtidal region of semiexposed coasts has a thallus composed of rodlike branches which are closely spaced, but the structure is sufficiently open so that water flows freely through it. The turbulence of the water before and after passing through the plant was measured by hot‐film anemometry in a water tunnel in the laboratory and observed by a dye stream technique in the tunnel and in situ in the sea. The flow after passing through the plant was smooth at velocities up to a critical value, but turbulent for velocities above an abrupt transition. Turbulence in the flow entering the plant did not change this result.Analysis of the results demonstrates that the plant strongly suppresses turbulence in the flow entering its thallus and at the same time generates microturbulence of its own at velocities above critical values varying from 6 to 12 cm·s−1, depending on the diameters and spatial density of the branches, due to the formation of systematic vorticity in the wakes of the individual branches. The transition in the flow induced by the branches of a marine plant is probably a phenomenon of considerable adaptive significance, because the turbulence generated by the plant itself or by neighboring plants may be the only turbulence in water motion past the plant that is of the right scale to enhance nutrient uptakes and effect the exchange of gases and solutes.
Comparative photoheterotrophy, chemoheterotrophy, and photolithotrophy in a eutrophic reservoir and an oligotrophic lake1
Authors: Ellis Bonnie K. , Stanford Jack A. 
Published: March 2010

Autoradiography was used to determine the role in the uptake of NaH14CO3 and [3H]glucose of specific microorganisms of two sizes (0.45–10 µm and 10–165 µm) in a eutrophic reservoir and an oligotrophic lake. Ultraplankton (0.45–10 µm) dominated plankton numbers and metabolic activity in both systems. An increase in photolithotrophy during the fall was due to an increase in the activity, numbers·ml−1, or both, of specific phytoplankters rather than an increase in the percentage of viable cells. Many of the most abundant species were not the most productive in terms of inorganic C fixation. Single species dominated total inorganic C fixation in both systems.Light‐mediated uptake of [3H]glucose was extensive in Flathead Lake; light bottle uptake averaged 365% of dark bottle uptake. Autoradiographs indicated that bacteria were responsible for the observed light‐mediated uptake of [3H]glucose in both lakes. Chemoheterotrophy dominated all Lake Texoma samples. Simultaneous in situ NaH14CO3 and [3H]glucose incubations in Lake Texoma revealed an ability of Oscillatoria agardhii (Gomont) to be mixotrophic as well as photoheterotrophic.
Production dynamics of some arctic Chironomus larvae
Authors: Butler Malcolm G. 
Published: March 2010

Production and standing stock were determined for a two‐species population of Chironomus larvae in a tundra pond near Barrow, Alaska, from 1975 through 1977. These larvae take 7 years from recruitment to adult emergence, and a multicohort population was always found. Cohort‐specific values for standing stock and annual production were calculated from size and abundance data for seven cohorts found in each sample. Total standing stock ranged from 6.7 to 12.3 g·m−2 (dry wt), and total annual production values were 5.4, 3.6, and 3.4 g·m−2 in the 3 years. Low temporal variation in both standing stock and annual production results from the multicohort structure of the population.Life table methods were used to estimate a value of 4.5 g·m−2 for cohort production over a 7‐year life cycle. Cohort P:B was 3.6, which is typical for Chironomus. Annual P:B values averaged only 0.49 because annual standing stock is about seven times greater than average cohort biomass over the life cycle, while annual production is comparable to cohort production.
Measurement of total inorganic carbon in seawater by a substoichiometric assay using NaH14CO3
Authors: Horner S. M. J. , Smith D. F. 
Published: March 2010

The total 12CO2 concentration ofa seawater sample can be accurately measured by adding a tracer quantity of NaH14CO3 in solution, acidifying the labeled seawater, and trapping a fraction of the gaseous 14CO2 + 12CO2 with a substoichiometric quantity of a quaternary amine (carbamate). If the same quantity of radioisotope is added to each of a set of standards and unknowns, the radioactivity of the carbamate will depend only on the specific activity of the label in the seawater sample.The decrease in carbamate radioactivity with increasing total 12CO2 in seawater is described by a simple functional relationship which is readily transformed to a linear equation. The method is well suited to the measurement of minute quantities of CO2 such as might arise from oxidation of dissolved organic carbon.
The dynamics of iron and manganese in a seasonally anoxic lake; direct measurement of fluxes using sediment traps
Authors: Davison W. , Woof C. , Rigg E. 
Published: March 2010

Twenty sediment traps were deployed for a year in five arrays at three locations in a seasonal anoxic basin in Esthwaite Water, U.K. Accumulated iron and manganese were measured fortnightly, as were vertical profiles of temperature, oxygen, total iron and manganese, polarographically determined Fe(II) and Mn(II), and light attenuance.Most of the iron and manganese flows into the lake in winter and is nearly all caught in sediment traps in deep hypolimnetic water, indicating that both elements are transported to the sediment. Accumulation rates in the sediments show that the iron is retained with minimal loss. Although dissolved iron increases to very high concentrations in the hypolimnion during the period of summer anoxia, this accumulation only accounts for a small fraction of the annual iron loading to the lake. The overall cycling of iron in the lake is consistent with a simple conception of sediment‐water interactions. When a redox boundary exists in the water column there is a separate cycle of iron due to vertical transport of ferrous iron by eddy diffusion, oxidation to Fe(III) by oxygen, sinking of the resultant ferric particles, and redissolution to ferrous iron. The manganese cycle contrasts markedly with that of iron. The manganese which reaches the sediment in winter is rapidly reduced and released to the overlying oxic water so that <10% is permanently accumulated in the sediment. During summer the manganese never reaches the sediment because it is reduced and accumulated in the anoxic hypolimnion. Relatively little manganese is supplied from the sediment during this time because the supply of particles is interrupted. Although most of the manganese which enters the lake is washed out again it will nearly all have undergone a redox cycle.
Photosynthetically produced dissolved organic carbon: An important carbon source for planktonic bacteria1
Authors: Cole Jonathan J. , Likens Gene E. , Strayer David L. 
Published: March 2010

A serial filtration technique was used to estimate microbial assimilation of photosynthetically produced dissolved organic carbon (PDOC) in Mirror Lake, New Hampshire. A single filtration at one pore size did not separate all heterotrophic microorganisms from photosynthetic algae. It was possible, however, to calculate microbial assimilation of PDOC if filters of several pore sizes were used simultaneously in combination with an independent estimate of heterotrophic activity in each size class.Microbial net assimilation of algal PDOC in the epilimnion in summer (about 2 µg C·liter−l d−1) was of a magnitude comparable to that of total bacterial production (4–8 µg C·liter−1 d−1) as estimated by the 35SO4 technique. This comparison suggests that PDOC is an important source of carbon for planktonic microbes.The amount of PDOC measured in the water is smaller than the amount actually released by phytoplankton because microbes metabolize PDOC rapidly. Failure to account for microbial utilization could lead to a serious underestimate of gross PDOC during measurements of primary production.
Grazing on epiphytes1
Authors: Cattaneo A. 
Published: April 2010

A correlation was found between the seasonal epiphyte cycle in Lake Memphremagog (Québec‐Vermont), with a maximum in mid‐June, and the abundance of grazers (mainly oligochaetes and chironomids). Evidence for a cause and effect relationship was provided by exclosure‐enclosure experiments. When grazers were excluded epiphyte biomass did not decline as it did in the lake. Addition of grazers to a dense epiphyte cover resulted in a decline qualitatively and quantitatively similar to that in the lake. Grazing pressure, calculated from general empirical equations for aquatic deposit feeders, was of the required order of magnitude to explain the decline in epiphyte biomass.Because similar seasonal epiphyte cycles have been described elsewhere these findings should have a wider relevance.
Selective predation by the backswimmer, Notonecta1
Authors: Scott Mary Ann , Murdoch William W. 
Published: April 2010

In laboratory experiments Notonecta hoffmani was size‐selective, although prey size alone did not explain its preference between prey species. When Notonecta was fed mosquito larvae, its preference first increased and then decreased with increasing prey size. Its consistent preference for the larger size class of a given species of zooplankton presumably reflects the fact that all zooplankton were small relative to the predator.Preference was determined mainly by differences in the relative attack rates on the different prey, but in two instances relative success rates of attacks were equally or more important. Although differences in the frequency of encounter influenced attack rates, the main determinant appeared to be the differences in the predator’s response to different prey once they were encountered. The results suggest that the behavior underlying Notonecta’s preferences is stereotyped and inflexible. The results help explain the effects of Notonecta on field populations of prey.
Phosphorus and calcium carbonate solubilities in Lake Kinneret
Authors: Avnimelech Yoram 
Published: April 2010

Phosphate and calcium carbonate solubilities were calculated from data obtained for near‐bottom water samples from Lake Kinneret during the years 1975–1977. A potential diagram technique was used to determine which solid phase is in equilibrium with the solution.Both phosphorus and calcium carbonate solubilities are controlled, during the January–August period, through equilibrium with calcium‐carbonate‐phosphate, Ca3(HCO3)3PO4. The calcium carbonate ionic product changes, depending on the phosphoric acid potential, during this period. The solubility product, (Ca2+)3 ×(HCO3−)3 ×(PO43−) is 10−28.5. Calcium carbonate activity is constant (10−8.56) during the last months of the stratified period (September–December).These findings support the hypothesis that the first and most reactive product of the reactions occurring between CaCO3 and phosphorus is a CaCO3H3PO4 surface complex.
Starvation in Daphnia: Energy reserves and reproductive allocation1
Authors: Tessier Alan J. , Henry Linda L. , Goulden Clyde E. , Durand Mark W. 
Published: April 2010

The relationship between energy reserves (biomass and triacylglycerol) and starvation time is investigated for two planktonic Cladocera, Daphnia. galeata mendotae and Daphnia magna. Triacylglycerol storage is correlated to total individual biomass independently of body size. Adult biomass increases twofold to threefold during the intermolt, with triacylglycerol accounting for 16% of the total increase. The amount of triacylglycerol transferred into each egg depends on the adult’s feeding success.Starvation time is correlated to body mass; however, triacylglycerol storage and reproductive allocation modify the relationship. Although adult biomass and percentage of lipid both increase during intermolt, animals in late intermolt starve sooner than those in early‐middle intermolt because of the transfer of energy reserves to the ovaries for reproduction. Daphnia magna neonates with high maternal lipid survived twice as long as neonates with low maternal lipid but similar body mass.
Photosynthetic parameters of arctic marine phytoplankton: Vertical variations and time scales of adaptation
Authors: Gallegos Charles L. , Platt Trevor , Harrison W. G. , Irwin Brian 
Published: April 2010

In the eastern Canadian arctic the photosynthesis‐irradiance curves of phytoplankton from the 50% and 1% light levels differ mainly in their susceptibility to photoinhibition. The photoinhibition parameters of deep populations and the intensity of the deep chlorophyll maximum were correlated with N2, the bulk stratification parameter of the water column. Comparison of data from the same region in different periods suggests that the characteristic susceptibility to photoinhibition requires 2–6 weeks to develop once a population is isolated below a pycnocline.Insensitivity to photoinhibition developed much more quickly when a population from the chlorophyll maximum was exposed to surface light. The threshold of photoinhibition increased rapidly, reaching surface intensities within 4–6 h. The adaptation is sufficiently rapid that phytoplankton from the chlorophyll maximum should be stressed only briefly when transported to the surface by a mixed‐layer‐deepening event.