bluuebunny/crossref_metadata_2025 huggingface dataset:
Predation rates of zooplankton in arctic ponds1
Authors: Dodson Stanley I.
Published: March 2010

Twelve species of arctic freshwater zooplankton were tested for predatory behavior in feeding trials, two species at a time, at several developmental stages. All were herbivorous as nauplii, early copepodids, or neonates. Heterocope septentrionalis and Acanthocyclops vernalis were common high‐intensity predators in the more mature stages. Daphnia middendorffiana and Polyartemiella hazeni were common passive predators in more mature stages. Cyclops vicinus, Diacyclops languidoides, Eucyclops agilis, Diaptomus alaskaensis, and Diaptomus bacillifer were not predaceous. The predator‐prey system in arctic ponds is complex; each predator serves as prey for some other species.
Sedimentation rates in a Long Island marsh determined by 210Pb dating1
Authors: Armentano T. V. , Woodwell G. M.
Published: March 2010

Mean rates of vertical accretion of from 0.47 to 0.63 cm yr−1 have been determined for the past century from two widely separated sites at Flax Pond, a Spartina alterniflora marsh on the north shore of Long Island. Sediments were dated from 210Pb activity. The rates are equivalent to deposition of 325 to 436 g of dry organic matter m−2 yr−1 or about 146 to 196 g of carbon m−2 yr−1 Although the two sites differed in salt peat thickness, the basal layer of the peat was deposited about 100 years ago at both.
Near‐bottom chemistry in the eastern Pacific and North Atlantic Oceans1
Authors: Culberson C. H. , Pytkoivicz R. M.
Published: March 2010

Near‐bottom chemistry at depths greater than 2,000 m was studied in the eastern tropical Pacific (27 stations), the northeastern Pacific (9 stations), the Caribbean Sea (1 station), and the North Atlantic (2 stations). Salinity, oxygen, pH, alkalinity, silicate, phosphate, and nitrate were measured at eight heights from 0.6 to 300 m above the bottom. No measurable salinity, oxygen, alkalinity, silicate, phosphate, or nitrate gradients were observed. A statistically significant near‐bottom increase in pH was found, but the increase was small and could have resulted from undetected analytical or sampling errors.
Ultrasonic treatment of sediment samples for more efficient sorting of meiofauna1
Authors: Thiel Hjalmar , Thistle David , Wilson George D.
Published: March 2010

The ultrasonic treatment of mei‐ofaunal samples breaks up sediment aggregations, permitting more efficient washing of the samples and reducing sorting time. Such treatment also allows recovery of specimens associated with fecal pellets and mud balls, and it cleans Foraminifera, improving their staining properties. Damage to agglutinating Foraminifera and certain other taxa limits the utility of the technique.
A large corer for quantitatively sampling benthos in shallow water1
Authors: Thayer Gordon W. , Williams Richard B. , Price Thomas J. , Colby David R.
Published: March 2010

A hydraulically operated device for obtaining cores 30.5 cm in diameter and up to 46 cm long is described. The corer is able to penetrate firm bottoms but is unsuited for water depths greater than 4 m. The corer was compared with a van Veen grab sampler in three substrate types in the Newport River estuary, N.C. In each case the corer yielded higher estimates of standing crops of macro‐invertebrates than the grab sampler; it also sampled deep‐dwelling invertebrates not sampled by the grab.
The role of tidal mixing in Rupert and Holberg Inlets, Vancouver Island
Authors: Drinkwater K. F. , Osborn T. R.
Published: March 2010

Analysis of monthly observations of temperature, salinity, and dissolved oxygen content in the basin formed by Rupert and Holberg Inlets reveals greater vertical mixing than in most British Columbia inlets. The water temperature correlates with solar radiation while the salinity changes follow river runoff, in turn controlled by precipitation. The variation in dissolved oxygen appears due to a combination of biological influences and the influx of water. A model has been developed which ascribes the monthly fluctuations and vertical homogeneity to an accumulation of irregular mixing events associated with the tidal flow through Quatsino Narrows, a shallow connecting channel.
Vertical patterns of eddy diffusion during stratification in Castle Lake, California1
Authors: Jassby Alan , Powell Thomas
Published: March 2010

The vertical eddy diffusivity for heat, Kz, which characterizes the intensity of vertical mixing, was estimated for depths below the epilimnion in Castle Lake, California, calculated from a series of temperature profiles collected during summer 1972 suitably corrected for solar radiation absorption. Kz was usually much larger than the molecular value of diffusivity, indicating that thermal energy is transported in the vertical almost entirely by turbulent mechanisms, even below the epilimnion. Further, Kz varied significantly with depth and was well described in the region of high stratification by the form Kz = b(N2)m, where m = −0.40 ± 0.02 and N2 =(Brunt‐Vaisala frequency)2, a result close to a previous theoretical prediction.
The long‐period internal waves in Lake Biwa
Authors: Kanari Sei‐ichi
Published: March 2010

The long‐period internal wave in a two‐layered model of Lake Biwa is treated numerically by the use of linear hydrodynamic difference equations for the equivalent volume transport rate and elevation.

Fourier analysis for the calculated time series of the interface at 29 sampling points in the model lake shows that the wave of the fundamental mode has a period of 66.1 h, about the same as the period of longitudinal internal seiches without the effect of the earth’s rotation, and that the wave progresses along the shore in a counterclockwise direction with an apparent phase velocity of about 1.5 km h−1.

Such rotatory behavior of the internal wave is consistent with the results of spectral analysis of the temperature records and with the result of an approximate analytical solution of the two‐layered rotating rectangular lake.
The spectral distribution of light beneath first‐year sea ice in the Arctic Ocean1
Authors: Maykut Gary A. , Grenfell Thomas C.
Published: March 2010

Spectral transmission data in the 400–1,000‐nm range were obtained from about 60 sites beneath first‐year sea ice near Point Barrow, Alaska. The amount of energy reaching the ocean depended strongly on the nature of the upper surface. Maximum transmission occurred in the 450–550‐nm region, regardless of surface conditions or ice thickness. Initial results were influenced by the presence of interstitial algae in the lower part of the ice. The characteristic signature of these algae was a secondary peak at about 540 nm. Results are generalized to provide estimates of the magnitude and composition of downwelling irradiance beneath the types of ice typically encountered in coastal portions of the Arctic Ocean.
Light responses of Daphnia pulex
Authors: Stearns Stephen C.
Published: March 2010

Individual Daphnia pulex were tested for activity responses in different wavelengths of light at the same intensity and at different times of day in white light at fixed intensity. The distance a daphnid moved in 5 min varied inversely with the wavelength of incident light. Daphnids tended to move vertically between 480 nm (blue) and 735 nm (red) and horizontally at 440 nm (violet) and in white light; this observation corroborates Smith and Baylor’s description of color dances. Daphnia pulex has a circadian activity rhythm. Total activity was low at night, increased to a peak in the morning, then declined through the afternoon. The color of ambient light is probably not a reliable indicator of the presence of phytoplankton in the water.
Omnivorous zooplankton and planktivorous fish
Authors: Confer John L. , Blades Pamela I.
Published: March 2010

The distance at which Lepomis gibbosus reacts to zooplankton is shown to be a linear function of prey size. If fishes sweep out a cylindrical path as they forage the frequency of prey encountered is then proportional to the square of this reaction distance. With the inclusion of the probability of capture success after a fish pursues a prey, a model of prey selection can estimate the effect of predacious zooplankton on the energy ingestion of planktivorous fish. Since predacious zooplankton are much larger and more visible to the fish than their own prey, this more than compensates for the energy lost by the additional trophic level and the moderate ability of predacious zooplankton to elude capture.
Potential temperatures in deep freshwater lakes
Authors: Farmer D. M.
Published: March 2010

A method is presented for finding potential temperatures in deep dimictic lakes. Though the adiabatic effect is very small it may be significant in special applications.
Present and historic geochemical relationships in four Maine lakes1
Authors: Sasseville Dennis R. , Norton Stephen A.
Published: March 2010

Undisturbed 1‐m cores of profundal sediment and overlying water were collected from four morphometrically paired Maine lakes with differing alkalinities and degrees of cultural development. Vertical variations in sediment chemistry correlate with the onset of European man’s activity in the watersheds of three of the lakes, although behavior is individual for any given element. Precultural core averages of P, S, organic matter, and diatoms are consistently higher in the sediments of the two deep oligotrophic lakes while the sediments of the two shallow mesotrophic lakes contain higher concentrations of quartz and aluminosilicate elements (K, Na, Ca, Mg, Al). This implies strong morphometric control of lacustrine sediment characteristics.

Interstitial water chemistry profiles are largely diffusion controlled, although “reactive” zones with very high concentration gradients arc present in all lake cores for various ionic species. The presence of these reactive zones near the sediment surface suggests a localized source and movement of these ions upward through the sediment‐water interface. Average interstitial water concentrations (exclusive of the major reactive zones) of P, Ca, Mg, and K are highest in the sediments of the two shallow mesotrophic lakes. Other dissolved species exhibit no clear relationships to lake type as characterized by alkalinity, trophic status, or degree of cultural influence.
Gas exchange rates in small Canadian Shield lakes1
Authors: Emerson Steve
Published: March 2010

A method for determining the transfer rate of gases between water and the atmosphere in the ocean, using the isotope pair 220Ra and 222Rn, is extended to small lakes in northwestern Ontario. Three independent experiments from 1971 through 1972 have established the gas exchange velocity in these lakes to be 0.2 ± 0.1 m day−1 (corresponding to a “boundary layer” of about 600 µ). This rate is one of the lowest observed in natural waters to date— less than a tenth of oceanic values and several times less than in the U.S. Great Basin lakes. A compilation of diverse gas exchange results, where wind velocity has also been measured, indicates that the results of laboratory experiments comparing wind velocity with gas transfer conform fairly well with the natural situation.
Results of sea surface mapping in the Peru upwelling system1
Authors: Kelley J. C. , Whitledge T. E. , Dugdale R. C.
Published: March 2010

Sea surface maps of temperature, salinity, nitrate, silicate, phosphate, and fluorescence were produced almost daily during a 6‐week cruise (PISCO) in the Peru upwelling system in the austral fall, 1969. The maps were produced by a shipboard computer from data gathered with the ship underway. The maps show persistent “plumes” of freshly upwelled water associated with coastal irregularities and prominent bathymetric features. The information on the location, orientation, and extent of these plumes was used to locate stations where primary productivity experiments were carried out. The definition of persistent plumes has led to the development of successful two‐dimensional simulation models of the ecosystem.
Linear measurements of growth of shells using laser diffraction
Authors: Stromgren Tor
Published: March 2010

An easy and rapid method of linear growth measurement of shells by laser diffraction is described that has a very high accuracy. Tested on Mytilus edulis it showed an average standard deviation of less than 3 µm. It has also been successfully applied to growth measurement of hydrocorals. The method is particularly useful for accurate measurements of fast growing species.
The relationship between temperature and the development of life stages of the marine copepod Acartia clausi Giesbr.1
Authors: Landry Michael R.
Published: March 2010

The durations of life stages of the marine copepod Acartia clausi relative to egg development time are consistently maintained when these animals are cultured with excess food at 10, 15, and 20°C. Seasonal acclimation effects, which have been shown to affect the egg development of A. clausi, are carried through an entire generation. Generation time or the development time of any postembryonic stage can be calculated from life history data at one temperature and the relationship between egg development at other temperatures regardless of the effect of acclimation.
Growth of oceanic phytoplankton in enrichment cultures1
Authors: Booth Beatrice C.
Published: March 2010

Twenty‐six species of phytoplankton were able to multiply in water collected from the surface at nine stations in the subarctic Pacific and enriched with nutrients. These species normally constitute 91% of the total cell numbers and 64% of the phytoplankton biomass in the collection area in the spring months.
A fluorometric technique for measuring sinking rates of freshwater phytoplankton1
Authors: Titman David
Published: March 2010

A recording fluorometer provides a rapid, automatic way to estimate sinking rates of freshwater phytoplankton, the determinations taking from 15 min for populations sinking at 1.0 m day−1 to 2 h for populations sinking near the limit of detection, 0.1 m day−1. The shape of the fluorescence output provides information on the distribution of sinking rates about the mean. Measured sinking rates of Asterionella formosa Hass. agree well with published data. Sinking rates of fluorescent micronic beads at various temperatures agree with Stokes’ law. The technique is applicable to marine phytoplankton, reducing the time needed for a determination two to five times over existing methods and so increasing the sensitivity that measurements may be directly possible for natural water samples.
Direct counts of aquatic bacteria by a modified epifluorescence technique1
Authors: Daley Ralph J. , Hobbie John E.
Published: March 2010

Various excitation and emission filters, microscope lamps, membrane filters, and field storage techniques used for direct counting of bacteria by epifluorescence microscopy have been compared. A rapid, simple modification of the Acridine Orange procedure using a new light filter combination, Sartorius cellulose membrane filters, and distilled water rinse gave the brightest cell fluorescence, darkest background, least fading, and highest counts for both estuarine and freshwater samples. Field fixation with Formalin permits storage of bacterial samples for 1 to 2 weeks without changes in bacterial numbers.
Two samplers for monitoring dissolved gases in lake water and sediments
Authors: Rudd John W. M. , Hamilton R. D.
Published: March 2010

An in situ vertical point sampler was used over several months to obtain dissolved gas samples from precise and reproducible points in the water column of a stratified lake. Sampling error of the apparatus was negligible.

A sediment gas sampler monitors concentrations by equilibration of dissolved pore wa ter gases with water inside plastic sample tubing, eliminating the problems of degassing and air contamination inherent to other sediment sampling systems. It is simple to construct and operate, enables close interval sampling across the sediment‐water interface and causes minimal disturbance of sediments and concentration gradients.
The effects of a benthic grazer on the primary productivity of the littoral zone of Lake Tahoe1
Authors: Flint R. Warren , Goldman Charles R.
Published: March 2010

A large population of crayfish (Pacifastacus leniusculus) inhabits the littoral zone of Lake Tahoe. The effect of crayfish grazing on the primary productivity of the periphyton was investigated in field and laboratory enclosures by varying the ratio of crayfish to substrate. In the field, primary productivity was enhanced after 66 days in a low density crayfish site and inhibited in a high density site. These results were duplicated in laboratory trials. Primary productivity of periphyton showed stimulation from grazer biomasses below 131 g m−2 but was inhibited by overgrazing when crayfish biomasses exceeded 203 g m−2. Grazing effects were also estimated on higher aquatic plant beds found in the littoral area of Tahoe by inclusion‐exclusion experiments. Any biomass of crayfish above about 69 g m−2 reduced standing crop of the macrophyte Myriophyllum sp. Nutrients contributed from feces of the crayfish significantly stimulated algal primary productivity. The crayfish, both as a grazer and as a contributor of nutrients, apparently supports present population levels and also acts as an effective agent in checking increases in benthic primary production.
Vertical distribution of nitrate concentration in interstitial water of marine sediments with nitrification and denitrification
Authors: Vanderborght Jean‐Pierre , Billen Gilles
Published: March 2010

Vertical concentration profiles of nitrate and nitrite in interstitial water of sediment in the Sluice Dock at Ostend (Belgium) commonly show a maximum in nitrate concentration at a few centimeters depth where sediments are sandy and poor in organic matter, while in muddy and organic‐rich sediments, nitrate is lower in interstitial water than in the overlying water and decreases rapidly with depth. Direct measurements of the activity of autotrophic nitrifying bacteria in the sediments show nitrification in the upper few centimeters of sandy sediments but not in muddy sediments.

A mathematical model is proposed to analyze quantitatively these experimental results, taking into account nitrification, denitrification, diffusion, and sedimentation. Seasonal variations of nitrate concentration in overlying water are slow enough to justify the use of a stationary (steady state) model. When appropriate values are used for the parameters (rate of nitrification, depth of the sedimentary layer in which nitrification occurs, rate of denitrification, diffusion coefficient), some being experimentally determined, the model predicts concentration profiles in good agreement with experimental data.
N2 : Ar, nitrification and denitrification in southern California borderland basin sediments1
Authors: Barnes R. O. , Bertine K. K. , Goldberg E. D.
Published: March 2010

The first quantitative observations of dissolved molecular nitrogen (N2) in deep‐sea sedimentary pore waters show increases of up to 17% above adjacent bottom water values. The N2 : Ar concentration ratio similarly increases. This increase is greater than expected from reduction of seawater nitrate in the sediment. A mechanism is suggested in which ammonia, derived from nitrogen‐containing organic matter, is converted to N2 through a nitrite intermediate under conditions of low oxygen tension. Ammonia is not converted to N2 in anoxic sediments that are undergoing sulfate reduction even though N2 is the thermodynamically stable species.
A possible origin of some olive‐green cells in aphotic marine environments1
Authors: Anderson O. Roger
Published: March 2010

Spheroidal cellular fragments were produced by resting cells of Amphora coeffaeformis (Bacillariophyceae) in laboratory cultures simulating the cold, dark conditions of aphotic ocean water. The light microscopic morphology and ultrastructure of these cellular fragments resemble olive‐green cells (group 1) that occur below the euphotic zone. The abundance of olive‐green cells in deep water beneath high productivity regions may result from the settling of phytoplankton into the dysphotic and aphotic zones where resting cells and their cellular fragments could be produced.
The acid‐bubbling method for primary productivity measurements modified and tested
Authors: Theodorsson Pall , Bjarnason Jon Orn
Published: March 2010

Acid‐bubbling has been proposed as an alternative method for separating the 14C‐carbonate from organic matter in determinations of primary productivity, but adhesion of plankton to the wall of the glass vessel used for bubbling can lead to low primary productivity values. A modified procedure is quite efficient compared with the conventional filtration method.
Discarded appendicularian houses as sources of food, surface habitats, and particulate organic matter in planktonic environments
Authors: Alldredge Alice L.
Published: March 2010

Observations using SCUBA reveal that macroscopic organic aggregates produced by appendicularians reached densities of 44 to 1,130 m−3 in the Gulf of California. Though these aggregates constituted less than 5% of total particulate carbon, their carbon : nitrogen ratio was twice that of particles in the surrounding seawater. The C : N ratio of the total particulate matter increased directly with the density of appendicularian produced aggregates. Aggregates were utilized extensively as food by euphausiid larvae, copepods, and planktivorous fish. Such aggregates affect the adaptive strategies and distribution of the plankton by introducing spatial heterogeneity and physical structure into an environment previously considered unstructured and may substantially alter the chemical composition of particulate organic matter.
Particle retention efficiencies of an herbivorous copepod, Acartia clausi (adult and copepodite stages): Effects on grazing1
Authors: Nival P. , Nival S.
Published: March 2010

From measurements of the distances between setules (mesh size) on the maxilla of Acartia clausi, a spectrum of filtration efficiencies for small particles has been established. The slope of the spectrum decreases from young stages (copepodite I) to adults. The average size of particle that can be collected increases slightly from 3 µ in CI to 7 µ in adult stages, whereas the size for which the efficiency is 100% increases sharply from 5 µ to 12 µ.

Two experiments were done to show the reality of the spectrum of filtration efficiency. A model of growth of particles and grazing by copepods, using the initial experimental conditions and the efficiency spectrum, was used to simulate the evolution of particles in the two experiments. The fit of the model to the experimental data is good for experiment I (dark) and the first 4 days of experiment II (natural daylight). The results of experiment II show that processes other than grazing become important in a long term experiment.
Feeding, growth, and food conversion of the marine planktonic copepod Calanus helgolandicus1
Authors: Paffenhofer Gustav‐Adolf
Published: March 2010

Food intake, growth rate, and food conversion of nauplii, copepodids, and adult females of Calanus helgolandicus were investigated experimentally at 15°C. The diatom Lauderia borealis and the dinoflagellates Gonyaulax polyedra, Gymnodinium splendens, and Prorocentrum micans were offered separately as food at concentrations ranging from 41 to 101 µg C liter−1. Amounts of food ingested differed with concentration and species. Daily exponential growth rates were highest for nauplii and young copepodids (k = 0.29 to 0.41) and decreased gradually with increasing age of the copepods to k = 0.02. Gross growth efficiency changed during the different juvenile life periods of the copepod with maximum values for the period CI to CIII. Feeding on L. borealis at lower food concentrations resulted in an increase in gross growth efficiency.
Phytoplankton production in the Great Salt Lake, Utah, and a laboratory study of algal response to enrichment1
Authors: Stephens D. W. , Gillespie D. M.
Published: March 2010

The annual production by phytoplankton in the southern basin of the Great Salt Lake as estimated at two stations in 1973 averaged 145 g C m−2. The majority of the production occurred during March and April and was due to an unidentified species of Dunaliella. Daily carbon fixation rates averaged 2.13 g C m−2 at both locations during this period. A minor phytoplankton bloom in August, due to a small, unidentified green flagellate contributed 5% of the total annual phytoplankton production. Phytoplankton production was probably limited during April by self‐shading and during the remainder of the year by the availability of nitrogen, as shown by laboratory bioassays. Grazing by Artemia salina reduces the phytoplankton population in late summer when nutrient levels have partially increased due to regeneration. The meromictic character of the lake was indicated by profiles of temperature and density. The monimolimnion is postulated to act as a nutrient sink, reducing the rate of nutrient release to the mixolimnion.
Phosphate utilization by an oceanic diatom in phosphorus‐limited chemostat culture and in the oligotrophic waters of the central North Pacific1
Authors: Perry M. J.
Published: March 2010

Thalassiosira pseudonana from the oligotrophic waters of the central North Pacific Ocean was grown in phosphorus‐limited chemostat culture. When the chemical composition of the cells, expressed as ratios, was compared with that of nitrogen‐limited cultures, several of these ratios varied in excess of a factor of five between the two systems. Among these, which emerged as diagnostic indicators of phosphorus‐starvation vs. nitrogen‐deficiency, were the C : P, N : P. P : Chl a and Chl a : ATP ratios.

The physiological responses of a population were determined by its preconditioning history. The minimum cellular phosphorus content, qo, varied with the degree of phosphorus starvation. The rate of phosphate uptake at a saturating concentration of phosphate by phosphorus‐limited cultures of T. pseudonana exceeded the rates of uptake by nonphosphorus‐limited cultures by an order of magnitude; the Ks for phosphate uptake was not a function of phosphorus deficiency.

Phytoplankton in phosphorus‐starved chemostat cultures on medium made with central North Pacific Ocean water did not use naturally occurring dissolved organic phosphorus despite the presence of cell‐surface alkaline phosphatase. Phosphate uptake by natural phytoplankton assemblages in the central North Pacific was measured with 33P. Uptake rates in the field were not significantly affected by light intensity. No circadian periodicity in uptake rates was detected in natural phytoplankton or algae cultured on a light/dark cycle.
Estimating water temperatures and time of ice formation on the Saint Lawrence River
Authors: Adams Charles E.
Published: March 2010

Monthly mean heat losses from the surface of the St. Lawrence River during the fall‐winter cooling period were determined by an empirical heat budget which incorporated the processes of radiation, conduction, convection, and precipitation. Calculations indicate that the heat loss can be reasonably represented by a simple linear relation with air‐water temperature differential. It is suggested however, that the coefficient of proportionality changes with variations in the ratio of radiation to evaporation. An equation was evaluated which relates surface heat loss to temperature decline along the international section of the river. Within the limits of accuracy of the heat loss calculations, the equation provides adequate estimates of water temperature changes for the period of study. The water temperature decline equation was used as the basis for developing a prediction technique which enables river freeze‐up estimates to be made as early as 1 October. When observed freeze‐up dates were used, predictions for a 6‐year period (1965–1970) yielded standard deviations of 4.7, 3.3, and 3.5 days for predictions starting at the beginning of October, November, and December. Observed freeze‐up occurred within 2 days of the predicted date in 4 of the 6 years examined. Experimental predictions for two additional years yielded similar results.
Skeleton growth of the hydrocoral Millepora complanata Lamarck in relation to light
Authors: Stromgren Tor
Published: March 2010

The daily length increment of the skeleton of the distal growing edge of Millepora complanata from Discovery Bay, Jamaica, was measured by laser diffraction. The individual variation in growth rates between adjacent and morphologically comparable parts of the same colony was pronounced. There was a significant correlation between length increment rate and light intensity. When daytime light intensities were high the length increment rates were slightly, but significantly, larger during night than during day.

A few measurements are also reported for Millepora alcicornis.
Limitation of phytoplankton species in the ocean off western Africa1
Authors: Hulburt Edward M.
Published: March 2010

The growth rate of phytoplankton off the west coast of Africa appeared not to be nutrient limited for two reasons. First, most of the species characteristic of nonupwelling regions did not show increased abundance in upwelling or productive regions where nutrient or other species were abundant. Second, in an upwelling region, where diatoms dominated, nutrients exceeded the half‐saturation values characteristic of diatoms.

A deductive model of the nutrient cycle, covering a complete range of nutrient concentrations, is used to interpret the field data. Since most species in the nonupwelling region were not limited, i.e. were not prevented from being abundant, by the small excess of nitrogen there, the compound statement ‘cells in the nonupwelling region were prevented from being abundant and cells in the upwelling region were not prevented from being abundant’ is false. Instead, the statement that ‘co‐occurrence of cells and excess nitrogen, with small and large amounts in the respective regions, was harmonious’ is true.
Blooms of surf‐zone diatoms along the coast of the Olympic Peninsula, Washington. 7. Variations of the carbon‐to‐nitrogen ratio in field samples and laboratory cultures of Chaetoceros armatum1,2
Authors: Collos Yves , Lewin Joyce
Published: March 2010

Carbon: nitrogen ratios in particulate matter collected from the surf at Copalis Beach, Washington, from April to September 1972 ranged between 5.0 (April, May) and 11.2 (July). They were considered characteristic of living algae in the surf, mainly the diatom species Chaetoceros armatum. The high ratio in summer could result from a slower growth rate of the diatoms or increased irradiance. The relationship between nitrate reductase (NR) activity and C : N ratios in surf samples and laboratory cultures was also investigated. In exponentially growing cultures of C. armatum C : N ratios varied from 4.2 to 13.5, depending on culture conditions.
Light utilization efficiencies of phytoplankton in Lake Kinneret (Sea of Galilee)1
Authors: Dubinsky Z. , Berman Thomas
Published: March 2010

A scanning radiometer was used for in situ determinations of the light utilization efficiencies of phytoplankton in Lake Kinneret. For a profile measured during the near maximum of daily irradiance in July, light utilization efficiencies in the epilimnion ranged from 0.07–2.61%, increasing with depth down to the thermocline where maximum quantum efficiencies of 0.07 moles C einstein‒1 absorbed were estimated. Light utilization efficiency integrated for the epilimnetic water column was 0.35%.
Major chemical and mineral components of profundal surface sediments in Minnesota lakes1
Authors: Dean Walter E. , Gorham Eville
Published: March 2010

Minnesota lakes, characterized primarily on the basis of water chemistry, can also be classified according to the proportions of organic matter, CaCO3, and clastic minerals in their profundal sediments. The northeastern (group 1) lakes are characterized by shallow to very deep basins in Precambrian crystalline rocks, active outlets, and dilute surface waters. Profundal sediments of these lakes contain no sedimentary calcium carbonate and can be subdivided on the basis of organic content. Highly organic sediments of group 1 lakes contain more than 30% organic matter (as loss on ignition), but most group I lake sediments contain less than this.

The central group 2 lakes occupy shallow to moderately deep basins in calcareous glacial till, have inactive outlets as a result of net evaporation, contain more concentrated salts than group 1 lakes, and commonly precipitate CaCO3 during the summer. These lakes can be subdivided on the basis of sedimentary CaCO3. Sediments of group 2 lakes with more than 30% organic material contain little or no CaCO3. Southern group 2 lake sediments are characterized by 10–30% CaCO3 and 10–30% organic matter. Sediments of western group 2 lakes contain 30–50% CaCO3 and about twice as much elastic as organic materials. Group 3 lakes occupy shallow depressions in calcareous, sulfur‐rich glacial drift of the arid southwestern prairie region and contain even more concentrated salts than group 2 lakes. Sediments in these lakes are mainly elastic, averaging about 12% organic matter and 20% CaCO3.

Variations in water and sediment chemistry, and in sediment mineralogy of these lakes are clearly related to an increase in climatic aridity and aquatic productivity from northeast to southwest. Differences in nature of the underlying glacial drift and in degree of erosion also affect the composition of the lake sediments.
Silicon‐32 specific activities in coastal waters of the world oceans
Authors: Lai D. , Nijampurkar V. N. , Somayajulu B. L. K. , Koide M. , Goldberg E. D.
Published: March 2010

Measurements of 32Si specific activities in siliceous sponges collected from the coastal waters of the world oceans provide insight into the mixing processes of waters having radically different silicon concentrations. The measured specific activities of in sponges, which should correspond to the values of dissolved silicon (and 32Si) in the coastal waters of the oceans, lie in the range of 4–80 dpm of 32Si kg‒1 SiO2. They are inversely correlated with the concentrations of dissolved silicon in coastal waters from which the samples were collected, and specific activities in the sponges are lower than those measured in surface (0–150 m) ocean waters by direct sampling.

In coastal regions there occurs a considerable influx of low specific activity continental waters and high specific activity intermediate and deep waters from the open ocean; the mixing between these various types of water, sampled by the sponge during its life time, determines the 32Si specific activity in sponges. Hence 32Si data in sponges should be useful for determining the budget of silicon in coastal regions.
Zooplankton: Specific distribution and food abundance1
Authors: Dodson Stanley I. , Edwards Candace , Wiman Fred , Normandin James C.
Published: March 2010

Does competition for food produce the distribution patterns we see for large versus small bodied zooplankton species in the absence of predation? Measurements of abundance of zooplankton food suggest that the disjunct distribution found between lakes is not due to competition for food. As much or more zooplankton food (bacteria <1 µ and nannoplankton 1–20.8 µ) occurred in ponds with large species as in nearby ponds with small species. This suggests that large zooplankton species do not out‐compete small species, with food density as the limiting resource.
Influence of sampling method on the chemical composition of water surface film
Authors: Daumas Raoul A. , Laborde Tierre L. , Marty Jean Claude , Saliot Alain
Published: March 2010

The composition of the surface microlayer was compared at two sites, having different degrees of water pollution, near the northern Mediterranean coast. Harvey (rotating drum device) and Garrett (screen) samplers were used and their effectiveness compared; the enrichment factor shown was greater with the former.

Eutrophication due to river runoff and hydrocarbon pollution from refinery effluents may contribute to an increase in the enrichment factor. Differences in chlorophyll, ATP, and pheophytin content between the two sampling methods suggest stratification of the living and inert planktonic material.
A new, simple method for gently collecting planktonic protozoa1
Authors: Graham Linda B. , Colburn Arthur D. , Burke John C.
Published: March 2010

An easy and gentle method for collecting planktonic protozoa is described: a 1‐liter polyethylene bag attached to a stainless steel, spring‐hinged sampling device is operated from a standard heavy‐duty fishing rod and reel. The sampler has been used successfully at depths from 1 to 300 m in ocean and in coastal waters. Acantharia and Foraminifera collected by this technique appear in excellent physical condition.
A light weight corer for sampling soft subaqueous deposits
Authors: Murray Declan A.
Published: March 2010

A light weight piston corer to obtain sedimentary cores up to 2.0 m long from soft subaqueous deposits is described. This corer, which may be used in any depth of water, uses cord rubber as the driving force to propel a core tube into the sediments.
Nitrogen fixation in Lake Mendota, Madison, Wisconsin1
Authors: Torrey Marguerite Sherman , Lee G. F.
Published: March 2010

The effects of various environmental conditions, and of cell composition, heterocyst content, and nitrogen content of algal samples, on fixation of N2 by colonial and filamentous algae in Lake Mendota were investigated.

Heterocyst content and temperature were significantly and positively related to acetylene reduction activity (N2 fixation); depth of sample collection was negatively related. Available data do not show whether statistical correlations of acetylene reduction activity with dissolved O2 and pH represent specific effects of O2 and pH on this activity, or simply reflect chemical changes caused by algal photosynthesis.

During summer stratification, when surface‐water content of combined inorganic nitrogen was severely depleted, N2 fixation associated with heterocystous blue‐green algae contributed 85% of the total N2 fixed. Bacterial N2 fixation was low compared to that of algae. Despite its small overall contribution to the annual nitrogen budget (38,000 kg of nitrogen; ca. 7% of the total input), N2 fixation is significant in maintaining blue‐green algal nuisances in surface water when non‐N2‐fixing phytoplankton cannot compete effectively.
Sinking in freshwater phytoplankton: Some ecological implications of cell nutrient status and physical mixing processes1
Authors: Titman David , Kilham Peter
Published: March 2010

Sinking rates of Asterionella formosa, Melosira agassizii, Cyclotella meneghiniana, and Scenedesmus quadricauda in stationary and exponential phases of growth are reported. Stationary phase populations sink 4× more rapidly, on the average, than exponentially growing populations. Time series of sinking rates during change from one growth phase to another demonstrate the viability of rapidly sinking cells. A consideration of sinking in Langmuir circulations indicates that the frequently used algebraic relationship between sinking rate and rate of loss of cells from the mixed layer may greatly overestimate loss rates. A theoretical net potential growth curve, that combines both loss from sinking and growth from sinking‐dependent nutrient uptake, demonstrates that nutrient depleted cells may have optimal growth rates (highest fitness) at high sinking rates.
The in situ growth rates of some deep‐living oceanic dinoflagellates: Pyrocystis fusiformis and Pyrocystis noctiluca1
Authors: Swift Elijah , Stuart Marc , Meunier Valerie
Published: March 2010

Division rates of Pyrocystis spp. were estimated for natural populations by determining the proportions of dividing cells produced each day. In Mona Passage (West Indies), P. fusiformis and P. noctiluca appeared to divide fastest at 80–100 m, the depth of their maximum cell concentration. Pyrocystis noctiluca divided at about the same rate in the mixed layer as in the thermocline, while P. fusiformis divided much more slowly in the mixed layer than below. In culture, reproductive stages of both species were negatively buoyant, but vegetative cells were positively buoyant. The effect of such buoyancy differences (and the rising and sinking rates which result from them) on the estimation of natural division rates was apparently negligible in the mixed layer and of some importance in the more stable waters of the thermocline.
Estimation of planktonic wind drift by transmissometry1
Authors: Baker Alan L. , Baker Kathleen Kromer
Published: March 2010

Halsted Bay (Lake Minnetonka, Minnesota) was surveyed with a transmissometer. Continuous surface transects and depth profiles revealed a pattern of distribution of phytoplankton that can best be described as wind drift. The relative composition of the phytoplankton, as well as its concentration, was modified by wind: blue‐green algae drifted downwind, while all other groups remained uniformly distributed. Regression analysis showed a linear relationship of alpha (beam attenuation coefficient) with total cell volume, chlorophyll a concentration, and dry weight of suspended particles.
The feeding rates of the pelagic tunicate Pegea confederata and two other salps1
Authors: Harbison G. R. , Gilmer R. W.
Published: March 2010

The filtration rates of Pegea confederata, Salpa maxima, and Cyclosalpa affinis were measured. Filtration rates increase exponentially with increasing length and body carbon. Filtration rates exceeding 100 ml min‒1 were recorded. The mucous net of P. confederata can retain particles at least as small as 0.7 µ. There appears to be no change in filtration rate with changes in particle concentration. Filtration rate per microgram of carbon increases with increasing body weight of salps in contrast to ascidians, perhaps because salps use muscular pumping rather than ciliary currents to transport water. The filtration rates recorded suggest that the role of salps in the open ocean ecosystem may be more important than previously assumed.
A volumetric temperature/salinity census for the Middle Atlantic Bight1
Authors: Wright W. R. , Parker C. E.
Published: March 2010

Two seasonal volumetric temperature/salinity diagrams have been prepared for the waters of the Middle Atlantic Bight from Nantucket Shoals to Cape Hatteras, to a depth of 200 m and extending as much as 130 km beyond the edge of the continental shelf. Total volume included is 23,145.6 km3, of which about half is slope water, more saline than 35‰. Most of it is in a distinctive subsurface maximum region near 13°C, which is named the upper slope water thermostad. The less saline shelf water has two modes divided by a minimum near 33.6‰. The fresher mode, associated with shallow depths, is identified as coastal water; that from 33.6–35‰ is called shelf edge water, and much of it is found seaward of the shelf break. There is very little seasonal change in the total volume of shelf water but its geographical distribution varies, showing the effects of spring runoff and suggesting a summer influx of slope water in the northern portion of the bight. Comparison with a similar census for the Gulf of Maine and shelf waters to the east shows some overlap but little evidence of substantial exchange.
The applicability of grain density autoradiography to the quantitative determination of algal species production: A critique
Authors: Knoechel R. , Kalff J.
Published: March 2010

Grain density autoradiography can be utilized to quantitatively determine the productivity of individual species in mixed phytoplankton assemblages but only after grain counts have been corrected for the effects of source geometry on efficiency as well as for the effects of spurious grain formation and erasure. The common simplifying assumption made by all workers to date, that the grain count over a cell is directly proportional to the cell’s radioactivity, is never realized with mixed species assemblages and such attempts at quantification are invalid. The procedure of apportioning total filterable radioactivity to the cells counted in autoradiographic preparations is also suspect. A method of data correction is presented which makes quantification feasible.
Lake Ontario circulation in November
Authors: Pickett R. L.
Published: March 2010

A Lake Ontario current meter study during November 1972 showed counterclockwise circulation with higher speeds in the western portion of the lake. Results from wind‐driven numerical models run for comparison agreed in the western section, but showed a clockwise gyre in the eastern portion of the lake.
Some observations on dinoflagellate population density during a bloom in a California reservoir1
Authors: Herrgesell Perry L. , Sibley Thomas H. , Knight Allen W.
Published: March 2010

Spatial and temporal distributions of Peridinium penardii were studied during a spring bloom. Blooms developed at the mouths of tributary streams after periods of high runoff and lasted for about 3 weeks. Allochthonous inputs may be necessary for the development of dinoflagellate blooms in this reservoir.
Manganese in Narragansett Bay1
Authors: Graham William F. , Bender Michael L. , Klinkhammer Gary P.
Published: March 2010

Concentrations of dissolved manganese and particulate manganese and aluminum were determined in samples from Narragansett Bay, Rhode Island, and its surrounding rivers. Total manganese is approximately conservative, but dissolved and particulate manganese are not. Desorption may occur in the tidal rivers at low salinities. Most riverine manganese is dissolved but manganese in the bay is predominantly particulate, probably due to rapid manganese oxidation at bay water pH.

The flux of dissolved manganese into bottom waters was about 2 ± 1 µg cm‒2 d‒1. Concentrations in bottom waters are high relative to surface waters.
The influence of colloidal organic matter on iron and iron‐phosphorus cycling in an acid bog lake1
Authors: Koenings Jeffery P. , Hooper Frank F.
Published: March 2010

The relationship between iron and phosphorus and the relationship of these elements to colloidal organic matter (COM) was studied in a meromictic acid bog lake by chemical characterization, filtration and in situ dialysis, and in situ experiments with labeled components.

Bathophenanthroline (BPN) reactive ferrous iron existed in true solution (dialyzable) in constantly anaerobic monimolimnetic water; in the aerobic epilimnion reactive ferric iron was of colloidal size. Intermediate depths, oxygenated only during spring, contained two forms of ferrous iron reactive to BPN: dialyzable ferrous iron (Fe2+) and colloidal Fe(II) which may have originated through in situ reduction of colloidal reactive ferric iron and may be present as a COM‐Fe2+ complex.

The amount of COM influenced the fate of dialyzable Fe2+ (92% of total iron) and dialyzable PO4‐P (85% of total phosphorus) present in anaerobic strata before aeration. Aeration with soluble organic matter present (COM absent) resulted in the formation of colloidal nonreactive ferric iron (84% of total iron) and 65% colloidal PO4‐P, while aeration with 26 mg liter‒1 COM resulted in only 36% colloidal, nonreactive ferric iron and 19% colloidal PO4‐P. COM apparently masks the cationic properties of colloidal ferric iron and retards the formation of nonreactive Fe (III), allowing most of the PO4‐P to remain free in solution and biologically available.