bluuebunny/crossref_metadata_2025 huggingface dataset:
Using the American Board of Internal Medicine Practice Improvement Modules to Teach Internal Medicine Residents Practice Improvement
Authors: Shunk Rebecca , Dulay Maya , Julian Kathy , Cornett Patricia , Kohlwes Jeffrey , Tarter Laura , Hollander Harry , O'Brien Bridget , O'Sullivan Patricia
Published: March 2010

Background

Although residency programs must prepare physicians who can analyze and improve their practice, practice improvement (PI) is new for many faculty preceptors. We describe the pilot of a PI curriculum incorporating a practice improvement module (PIM) from the American Board of Internal Medicine for residents and their faculty preceptors.

Methods

Residents attended PI didactics and completed a PIM during continuity clinic and outpatient months working in groups under committed faculty.

Results

All residents participated in PI group projects. Residents agreed or strongly agreed that the projects and the curriculum benefited their learning and patient care. A self-assessment revealed significant improvement in PI competencies, but residents were just reaching a “somewhat confident” level.

Conclusion

A PI curriculum incorporating PIMs is an effective way to teach PI to both residents and faculty preceptors. We recommend the team approach and use of the PIM tutorial approach especially for faculty.
Patient-Centered Collaborative Care: The Impact of a New Approach to Postpartum Rounds on Residents' Perception of Their Work Environment
Authors: Baldwin Maureen , Hashima Jason , Guise Jeanne-Marie , Gregory William Thomas , Edelman Alison , Segel Sally
Published: March 2010

Objective

At our institution, traditional postpartum rounds consisted of separate visits from all members of the obstetric team. This led to patient care inefficiencies and miscommunication. In an effort to improve patient care, patient-centered collaborative care (PCCC) was established, whereby physicians, residents, medical students, nurses, case managers, and social workers conduct rounds as a team. The goal of this observational study was to evaluate how PCCC rounds affected resident physicians' assessment of their work environment.

Methods

Obstetrics and gynecology residents completed a 13-question written survey designed to assess their sense of workflow, education, and workplace cohesion. Surveys were completed before and 6 months after the implementation of PCCC. Responses were compared in aggregate for preintervention and postintervention with Pearson χ2 test.

Results

Ninety-two percent of the obstetrics residents (n  =  23) completed the preintervention survey, and 79% (n  =  19) completed the postintervention survey. For most measures, there was no difference in resident perception between the 2 time points. After implementation of PCCC rounds, fewer residents felt that rounds were educational (preintervention  =  39%, postintervention  =  7%; P  =  .03).

Conclusion

Residents did not report negative impacts on workflow, cohesion, or general well-being after the implementation of PCCC rounds. However, there was a perception that PCCC rounds negatively impacted the educational value of postpartum rounds. This information will help identify ways to improve the resident physician experience in the obstetric service while optimizing patient care.
On-site Night Float by Attending Physicians: A Model to Improve Resident Education and Patient Care
Authors: DeFilippis Andrew Paul , Tellez Ildefonso , Winawer Neil , Di Francesco Lorenzo , Manning Kimberly D. , Kripalani Sunil
Published: March 2010

Background

In 2003, the Accreditation Council for Graduate Medical Education instituted common duty hour limits, and in 2008 the Institute of Medicine recommended additional limits on continuous duty hours. Using a night-float system is an accepted approach for adhering to duty hour mandates.

Objective

To determine the effect of an on-site night-float attending physician on resident education and patient care.

Methods

Night-float residents and daytime ward residents were surveyed at the end of their rotation about the impact of an on-site night-float attending physician on education and quality of patient care. Responses were provided on a 5-point Likert scale ranging from 1, strongly agree, to 5, strongly disagree.

Results

Overall, 92 of the 140 distributed surveys were completed (66% response rate). Night-float residents found the night-float attending physician to be helpful with cross-cover issues (mean  =  2.00), initial history and physical examination (mean  =  1.56), choosing appropriate diagnostic tests (mean  =  1.79), developing a treatment plan (mean  =  1.74), and improving overall patient care (mean  =  1.91). Daytime ward residents were very satisfied with the quality of the admission workups (mean  =  1.78), tests and diagnostic procedures (mean  =  1.76), and initial treatment plan (mean  =  1.62) provided by the night-float service.

Conclusion

A night-float system that includes on-site attending physician supervision can provide a valuable opportunity for resident education and may help improve the quality of patient care.
Some of the Factors Affecting the Calibration Number of the Clarke‐Bumpus Quantitative Plankton Sampler1
Authors: YENTSCH CHARLES S. , DUXBURY ALYN C.
Published: March 2010

Calibration values obtained by standard “field” calibration procedures are in error because a portion of the water encountered during the tow is rejected. A method is described by which the actual volume of water passing through the sampler is measured without disrupting normal flow characteristics around or through the meter. Depending upon net attachment and towing velocity, the percentage of water accepted varies from 90–94 per cent. An attempt has also been made to evaluate the effects of net clogging on calibration values.
The Ionic Composition of Some Lowland Lake Waters from Cheshire, England
Authors: GORHAM EVILLE
Published: March 2010

Analyses are presented for the major dissolved constituents in waters from nine Cheshire meres. Calcium and bicarbonate ions predominate, but there are also large proportions of magnesium, sodium, sulphate, and chloride in these rather concentrated waters. The two lakes lacking inflow and outflow streams are chemically aberrant, and it appears that their ionic composition is greatly influenced by that of rain. The chemistry of the normal mere waters reflects the arid conditions in which the underlying Keuper marls were deposited.
The Tidal Migrations of Donax variabilis Say1
Authors: TURNER HARRY J. , BELDING DAVID L.
Published: March 2010

The behavior of the beach clam, Donax variabilis, resembles that of Donax semigranosis in that it migrates up and down the beach with the rise and fall of the tide assisted by the wash of the surf. On the rising tide the acoustic shock of the breaking waves stimulates the bivalve to emerge from the sand in advance of the uprush so that the wash carries it up the beach. On the falling tide it ignores the acoustic stimulus and emerges into the backwash to be carried down the beach. The reactions may be due to an intrinsic rhythm, changes in the water content of the sand, or a trigger‐and‐memory mechanism.
Ecological Studies on the Planktonic Protozoa of a Small Artificial Pond1
Authors: BAMFORTH STUART S.
Published: March 2010

A one‐year survey was conducted on a small artificial pond to determine environmental relationships of planktonic protozoa to physical and inorganic chemical factors.

Collections were made at 9:00 A. M., Eastern Standard Time, every other day. Planktonic samples were taken from the surface and bottom, and sunlight intensity and temperature were measured. Chemical analyses included alkalinity, carbon dioxide, chloride, dissolved oxygen, nitrate, nitrite, ammonia, phosphate, pH, hardness, and turbidity. Bacteria counts were made microscopically, and protozoa were handled by the Sedgwick‐Rafter method.

The order of appearance of phytoplankton may have been influenced by the abundance of growth factors coupled with varying amounts of dissolved substances: Cryptomonas appeared in autumn and early summer; chrysomonads and Chlamydomonas in winter; Glenodinium, Pyramimonas, and diatoms in spring; and euglenoids in summer.

The amount of phosphate seemed to influence which phytoplankters appeared: chrysomonads were not found when the water contained more than 0.02 ppm of phosphate, whereas cryptomonads and diatoms increased at this concentration, and euglenoids were abundant at several times this concentration. Within each phosphate range other factors, such as nitrogen sources and growth factors, exercised more immediate effects. Supply of organic nutrients appeared to influence euglenoid numbers.

Increases in sunlight and temperature were favorable for diatoms but unfavorable for Glenodinium cinctum and Trachelomonas hispida.

The nature and amount of food appeared to be the controlling factor for ciliates.

Many plankters live perilously close to minimum survival conditions, and slight environmental changes can promote rapid growth, reduction, or subsidence of a population. This survey shows that detailed studies are necessary to ascertain ecological relationships of microorganisms, and that protozoan habitats must be defined more precisely.
The Effect of Grain Size on the Distribution of Small Invertebrates Inhabiting the Beaches of Puget Sound
Authors: WIESER WOLFGANG
Published: March 2010

The position with respect to the general configuration of the shore‐line and the direction and force of the currents of five localities in Puget Sound is such that they represent a series of decreasing exposure, Richmond Beach being the most exposed, Bainbridge Island the most sheltered locality. This is reflected in the composition of the substrate, the former locality having the coarsest, the latter the finest substrate. Perpendicular to this horizontal gradient there runs a vertical gradient due to the tide, the coarse grades being deposited in the upper, the fine grades in the lower intertidal.

The intertidal distribution of at least some of the more common species of invertebrates on the beaches is not so much determined by levels of tidal water as by the pattern of distribution of certain grades of substrate. For example, species of this sort will penetrate into the upper intertidal if the preferred substrate occurs there, but they will remain in the lower intertidal if the substrate is confined to this zone.

On the beaches there exist mixtures of sand which constitute barriers separating major faunal components from each other. It is assumed that substrates with a median diameter of approximately 200µ constitute such a barrier separating the bulk of interstitial sliders from a great number of burrowing animals. The former can move only in sand coarse enough to maintain an interstitial system; the latter, for mechanical reasons, will find fine sand more favorable than coarse. This distinction, however, does not apply to nematodes which are able to move even in the interstices of fine sand. There are various ways in which grain size and shape can influence the distribution of the fauna. These types of relationship are discussed.
SEASONAL CHANGES IN THE ATTACHED ALGAE OF FRESHWATER AND SALINE LAKES IN THE LOWER GRAND COULEE, WASHINGTON1
Authors: Castenholz Richard W.
Published: March 2010

A two year investigation of two freshwater alkaline lakes and two saline lakes in the Lower Grand Coulee has provided a quantitative and qualitative record of many of the seasonal changes occurring in the non‐planktonic algae. A glass plate method satisfactorily recorded quantitative changes in the attached algae. The plates (28 by 28 cm) were submerged for 2 to 4 weeks at various depths. Dry weight and ash‐free dry weight of the predominantly algal attachment materials on plates were determined, and the ash‐free weight was expressed as a production rate. The ash from freshwater lakes was composed normally of intact diatom frustules. The ash from saline lakes was also diatomaceous, but the weakly silicified frustules were deformed during ashing. Proportional counts of the various species in freshwater lakes were made using the ash. The evaluation of relative dominance was based on the mathematical product of the cell count and a calculated volume factor for each species. The glass‐plate production technique was examined at some length and it was concluded that a 2‐week submergence period was most satisfactory, that glass was not unduly selective, that a horizontal position was satisfactory, and that the method was best suited to the freshwater lakes.

In freshwater lakes (200–450 ppm T.D.S.) results clearly show a bimodal production curve with the peak generally higher in the spring than in the fall. Lowest production invariably occurred in late summer. High production values in the spring were commonly near or above 500 mg/m2/day. Comparison of the results of two years shows sizable differences in total production at comparable times of year, but the seasonal distribution of species followed the same general pattern both years. Cymbella affinis, C. cistula, C. mexicana, Diatoma elongatum, Fragilaria vaucheriae, Gomphonema eriense, Nitzchia spp., Synedra acus, and S. ulna were characteristic spring dominants in the freshwater lakes. These diatoms were replaced in summer mainly by Epithemia sorex, E. turgida, and Rhopalodia gibba. A few “spring” species were common in one lake in summer but only at greater depths. The

Nine per cent of the 275 algal taxa collected in the Lower Grand Coulee occurred in both freshwater and saline lakes. Although the saline lakes were not rich in numbers of species, production rates were similar to and even higher than production rates in the freshwater lakes. In the two saline lakes (Lake Lenore‐10,000 ppm and Soap Lake—25,000 ppm) there was a pronounced diatom pulse in the fall. Production rate values as high as 550 mg/m2/day were achieved during this season. In Soap Lake a winter pulse reached a value of 1000 mg/m2/day which was followed by a distinct spring pulse, both absent in Lake Lenore. The dominants on glass plates in both lakes were species of Nitzschia and Amphora. Blue‐green algae were also common and were conspicuous for their lack of seasonality.
TEMPERATURE, SALINITY, AND SOUTHERN LIMITS OF THREE SPECIES OF PACIFIC COTTID FISHES
Authors: Morris Robert W.
Published: March 2010

Three species of cottid fishes, Oligocottus maculosus, Clinocottus globiceps, and Leptocottus armatus, were subjected to tests to determine their relative degree of tolerance of elevated temperature and salinity. They were found tolerant of approximately double strength sea water for up to 14 hours, at 12°C. Elevation of temperature resulted in partial failure of osmoregulation at about 16°C in the first two named species and at about 25°C in L. armatus. The temperature related reaction to osmotic stress can be related to maximum shore temperatures at the southern extremity of the ranges of O. maculosus and C. globiceps. In intraspecific comparison, tolerance of elevated salinity does not imply tolerance of high temperature and vice versa.
ISOLATION OF YEASTS FROM BISCAYNE BAY, FLORIDA AND ADJACENT BENTHIC AREAS1, 2
Authors: Fell Jack W. , Ahearn Donald G. , Meyers Samuel P. , Roth Frank J.
Published: March 2010

Investigations of the yeasts present in Biscayne Bay, Florida, have indicated the occurrence of various yeast taxa, representing 179 isolates, including species of Saccharomyces, Hansenula, Debaryomyces, Candida, Cryptococcus, Rhodotorula, Trichosporon and Torulopsis. Two asporogenous species, Candida tropicalis and Rhodotorula mucilaginosa, were the most abundant and widely distributed species in the Bay. A yeast biota, with many species similar to those isolated from Biscayne Bay, has been collected in deep sea sediments from The Bahamas. A selective enrichment culture technique has been developed, greatly facilitating the collection of yeasts from the marine environment. In general, the limited deep sea collections showed a predominance of oxidative yeasts as compared to collections made in Biscayne Bay.
ON INTERNAL WAVES IN LAKES
Authors: Bryson Reid A. , Ragotzkie Robert A.
Published: March 2010

The dominant feature of short period thermal unrest in a stratified lake is the periodic nature of the temperature variation. When such variations at a point occur within a few minutes, periodic vertical motions of the water are implied, for other heat transfer mechanisms within the lake are too slow. These periodic motions, internal waves, may be studied at a given depth by simultaneous continuous temperature measurement at three closely spaced stations. From these observations and the mean vertical gradient the amplitude, direction, period, and speed of the internal waves have been determined.

Long, standing internal waves have been described often in the literature as seen through temperature observations. They may also be studied by means of their “surface reflection.”
SALINITY OF INTERSTITIAL WATER IN A SANDY BEACH
Authors: Johnson Ralph Gordon
Published: March 2010

The salinity in the upper 20 cm of intertidal sands was observed at two stations in Tomales Bay, California. In summer, there were no striking variations associated with elevation, except for the effect of evaporation. In winter, the influx of freshwater provides sufficient contrast between interstitial and open water to reveal features of circulation. High on the beach, the interstitial salinity at the 10‐ and 20‐cm depth remains low through the tidal cycle. The salinity at 10 cm remains higher than at 20 cm. At an elevation of 1.0 m, the salinities at 10 and 20 cm converge. Below this elevation, interstitial salinity varies less than in the adjacent open waters of the bay. The environment of the infauna of the low intertidal zone is more stable than that of epifaunal or pelagic organisms in shallow water. The variations high in the intertidal zone must constitute a major obstacle to the spread of marine organisms into this area.
OBSERVATIONS OF THERMOPHILIC ALGAL COMMUNITIES IN MOUNT RAINIER AND YELLOWSTONE NATIONAL PARKS
Authors: Stockner John G.
Published: March 2010

Observations on thermophilic algal communities during a three‐year period at Mount Rainier National Park and during January 1965 and 1966 in Yellowstone National Park have been analyzed to evaluate the distribution of species in thermal streams relative to temperature and competitive interaction. Although temperature appears to be the most important physical factor affecting the distribution in alkaline springs, interspecific competition for space also influences the distribution. Diatom species commonly occurring above 35C are noted, along with the apparent tolerance by certain species of temperatures in excess of 45C. The diversity of the diatom flora increases as the water cools. Despite thermal and chemical constancy, the growth rate of the algae is negligible during the winter months when light is minimal.
NUTRITIONAL, PHYSIOLOGY OF METRIDIA LUCENS AND M. LONGA FROM THE GULF OF MAINE1
Authors: Haq S. M.
Published: March 2010

Respiration, feeding, and assimilation were studied in two species of Metridia from the Gulf of Maine. The smaller M. lucens respired at a higher rate per unit dry weight than the large form, M. longa. M. lucens demonstrated a normal physiological response to increasing temperature up to 18C and M. longa up to 14C. Maximum respiration occurred during spring for both species and tended to decline in fall and winter. Both species were similar in their feeding behavior. Filtration rate was inversely related to food concentration, but the slope of the curve varied with different foods. With small‐sized food (5 µ), the filtration rate was generally lower than with the large‐sized food (300 µ). Food ingestion increased with increasing food concentration up to a certain level, beyond which it declined. Maximum ingestion of organic matter was less with small than with large‐sized food. Both species exhibited strong preference for animal food (Artemia nauplii) over phytoplankton when offered together. Filtration rates were insufficient to meet respiratory losses at concentrations of particulate carbon found in the Gulf of Maine, whereas studies with Artemia nauplii suggest that the animals were able to acquire food in excess of their respiratory requirements. Dietary requirements were met more easily from a mixed diet than from a single food. M. longa was less attracted to laboratory food, and the amount of food ingested was not consistent with its greater body size. M. lucens was a voracious feeder and must be considered an important predator on small zooplankton. The fat content of M. longa was generally higher than that of M. lucens.
SURFACE CHEMICAL CHARACTERIZATION OF SURFACE‐ACTIVE MATERIAL IN SEAWATER
Authors: Jarvis N. L. , Garrett W. D. , Scheiman M. A. , Timmons C. O.
Published: March 2010

Seawater samples were collected using a technique that isolated the upper 0.15 mm of surface water. Much of their organic matter was surface‐active, slick‐forming material that was originally at the seawater‐air interface. These surface‐active molecules are of interest because of their influence on many properties of the sea surface. Determinations were made of the effect of monolayers of these materials on the surface tension, on the surface potential, on the damping of capillary waves, and on the surface viscosity. The measurements were made as functions of the area of surface occupied by the adsorbed molecules. Organic materials collected from widely different locations were surprisingly similar in their behavior, suggesting that the more strongly adsorbed, stable, film‐forming materials at the interface were chemically similar. It is suggested that the more stable components of the films are primarily polar‐nonpolar compounds containing long‐chain hydrocarbon groups, such as the high molecular weight saturated and unsaturated fatty acids and their esters.
A STUDY OF SELECTED MECHANISMS FOR THE COEXISTENCE OF DIAPTOMUS SPP. IN CLARKE LAKE, ONTARIO1
Authors: Sandercock Gail A.
Published: March 2010

The following mechanisms have been suggested to explain the coexistence of different Diaptomus species: vertical segregation, seasonal separation, and size differences. Three species of Diaptomus (D. minutus, D. oregonensis, and D. sanguineus, in order of increasing size) occur in Clarke Lake, Ontario. D. minutus was vertically separated from D. sanguineus, and there was a distinct size difference between the two. D. minutus and D. oregonensis showed different seasonal maxima and were separated by size differences. D. sanguineus and D. oregonensis were separated vertically and had different seasonal maxima. A combination of two mechanisms allows coexistence of each of the three Diaptomus species‐pairs in Clarke Lake.
THE POTENTIAL TROPHIC SIGNIFICANCE OF CALLIANASSA MAJOR FECAL PELLETS1
Authors: Frankenberg Dirk , Coles Stephen Lee , Johannes R. E.
Published: March 2010

The trophic significance of the fecal pellets of Callianassa major was investigated by measuring 1) the rates at which fecal material was produced, 2) its organic carbon and nitrogen content, and 3) its ingestion by other animals. Our results indicate that 456 ± 118 fecal pellets are produced per burrow per day and from 175 ± 46 to 2,600 ± 670 pellets m−2 day−1, depending on population density, and that an entire C. major population occupying an area of about 200,000 m2 produces about 280 × 106 pellets/day. The carbon and nitrogen contents of the pellets were 3 and 0.3% of their dry weight. Aging the pellets had no effect on their carbon content but halved the nitrogen content in 48 hr. Ingestion experiments indicated that fecal pellets were eaten by hermit crabs, probably by blue crabs, and possibly by several other beach inhabitants.

The results were used to calculate the rate at which organic carbon is made available in fecal pellets, and this rate was compared to production rate measurements for local primary producers. The potential quantitative significance of fecal pellets as a food source is discussed.
THE DISTRIBUTION OF AQUATIC OLIGOCHAETES IN SAGINAW BAY, LAKE HURON
Authors: Brinkhurst Ralph O.
Published: March 2010

There is little correlation between the abundance of Oligochaeta in bottom samples collected by the Michigan State Conservation Department and the U.S. Bureau of Commercial Fisheries, Ann Arbor, during 1965 and the environmental factors measured. The factors of primary significance for the determination of habitats of oligochaete species have yet to be identified. Their distribution in Saginaw Bay is influenced by the inflow of the polluted Saginaw River, as evidenced by the presence of Paranais litoralis and the high percentage of Limnodrilus hoffmeisteri in samples from the innermost part of the bay.
ADSORPTION OF SURFACE‐ACTIVE MATERIAL AT THE SEA—AIR INTERFACE1
Authors: Jarvis N. L.
Published: March 2010

Surface tension and surface potential measurements were used to detect the adsorption of surface‐active material at the sea‐air interface. With undisturbed water samples, several hours were often required for a significant decrease in surface tension to be observed. The rate of adsorption increased remarkably when a stream of air bubbles was passed through the water, or when the water was stirred vigorously. In the Bay of Panama, the concentration of readily adsorbed surface‐active material was rather constant with depth from the few centimeters at the surface to at least 20 m. Only the thin layer of water at the interface showed a significantly greater concentration.
PULSED LIGHT STIMULATION OF MARINE BIOLUMINESCENCE IN SITU
Authors: Neshyba Steve
Published: March 2010

Experiments on the luminescent response in marine organisms subjected in situ to pulses of colored light are discussed. White light stimuli enhance the level of the bioluminescent field as much as 1,000 times. The reaction is greater to white and blue‐green stimuli than to blue, green, or red. For all stimuli except red, the reaction appears to have three distinct characteristics, 1) a relatively short flash response, 2) an intermediate response lasting 10 sec or more, and 3) a long‐term response of several minutes’ duration. The intermediate response accounts for most of the increase in the level of luminescence during stimulation. The experimental results are interpreted in terms of the design of optical sensors to which the bioluminescent field is a source of spurious signals.
THE DISTRIBUTION OF COPPER IN TROPICAL SEAWATER1
Authors: Alexander J. E. , Corcoran E. F.
Published: March 2010

The concentrations of the ionic, particulate, and total soluble copper in waters off Florida were determined spectrophotometrically. Most of the copper was in the soluble organic complex. Nearshore waters had significantly more total copper (approximately 20 µg/liter) than the waters flowing through the center of the Straits of Florida (approximately 10 µg/liter). Ionic copper concentrations were always less than 2µg/liter, and the particulate copper concentrations rarely exceeded 0.2 µg/liter.
DETERMINATION OF THE APPARENT DISSOCIATION CONSTANTS OF PHOSPHORIC ACID IN SEAWATER1
Authors: Kester Dana R. , Pytkowicx Ricardo M.
Published: March 2010

A method was developed for determining the apparent dissociation constants of a tribasic acid in complex concentrated ionic solutions using potentiometric pH measurements and acid‐base titrations. The apparent dissociation constants of phosphoric acid were determined in artificial seawater over the ranges of temperature and salinity normally encountered in the ocean. These apparent dissociation constants were also measured in 0.68 m NaCl, which has the same ionic strength as seawater of 33‰ salinity. It was estimated that 99.6% of the PO43− species and 44% of the HPO42− species are complexed by cations in seawater other than Na+. The values of the apparent dissociation constants reveal that in seawater of 33‰ salinity at 20C at pH 8.0, 87% of the inorganic phosphate exists as HPO42−, 12% as PO43−, and 1% as H2PO4− .
THE DISTRIBUTION OF TENDIPES PLUMOSUS (LINNÉ) IN MINERAL ACID WATER1
Authors: Harp George L. , Campbell Robert S.
Published: March 2010

Tendipedid populations from 19 strip‐mine lakes of varying pII were analyzed. Tendipes plumosus (Linné) was the sole tendipedid established in water with measurable potential free acidity. In lakes lacking potential free acidity, T. plumosus, when present, was frequently accompanied by other tendipedid species. It is suggested that the distribution of T. plumosus was not restricted by a mineral acid environment, but was related to the presence of leaf litter.
PHYTOPLANKTON, SESTON, AND DISSOLVED ORGANIC CARBON IN THE LITTLE MIAMI RIVER AT CINCINNATI, OHIO
Authors: Weber Cornelius I. , Moore Donald R.
Published: March 2010

A yearlong study was made of the phytoplankton, seston, and dissolved organic carbon in a small, hardwater, midwestern stream. The annual cycle of cell counts and volumes followed the cycle in water temperature. The dominant algae were small, euplanktonic, centric diatoms of the genera Cyclotella, Melosira, and Stephanodiscus, which contributed an average of 63% of the cell count and 66% of the cell volume. The seston averaged 15.8% organic matter by ignition. Stream flow and particulate organic matter were positively correlated from December to April, negatively from May to November. The phytoplankton contributed an average of 38% of the particulate organic matter from May to November. The dissolved organic carbon averaged 6.4 mg/liter, and showed no seasonal cycle.
ADENOSINE TRIPHOSPHATE CONTENT OF MARINE BACTERIA1
Authors: Hamilton Robert D. , Holm‐Hansen Osmund
Published: March 2010

The adenosine triphosphate (ATP) content of seven selected cultures of marine bacteria, representing five genera, has been determined during growth in chemostats and during the various growth phases in batch cultures. The range of ATP content in chemostat‐grown cells was 0.5–6.5 × 10−0 µg ATP/cell, or 0.3 to 1.1% of the cell carbon. The ATP content of senescent cells in batch cultures and in starved cells was generally about one‐fifth the concentration found in logarithmically growing cells. The average content of ATP in all the bacteria examined was 0.4% of cell carbon. It is concluded that ATP data can provide a useful estimate of heterotrophic biomass in the oceans.
ON THE OCCURRENCE AND FORMATION OF SMALL PARTICLES IN SEAWATER
Authors: Sheldon R. W. , Evelyn T. P. T. , Parsons T. R.
Published: March 2010

Size distributions are given of particulate matter in suspension at the surface and at various depths to 400 m in the Strait of Georgia, British Columbia. The distributions at depth do not appear to arise from settling of particles from the surface; one possible reason is that particle formation takes place in situ. It is shown that particles will form in undisturbed membrane‐filtered seawater under a variety of conditions and that this phenomenon occurred in the presence of bacteria. Particles larger than 1.58 µ could only be produced to certain limiting concentrations, usually less than 1 ppm by volume, and the final concentration formed depended on the origin of the water. If the particles were filtered from the water, another period of particle formation would occur. The possible importance of these particles in the marine economy is discussed with particular reference to filter feeders.
STUDIES OF THE RELEASE OF DISSOLVED FREE AMINO ACIDS BY MARINE ZOOPLANKTON1
Authors: Webb Kenneth L. , Johannes R. E.
Published: March 2010

Rates of release of dissolved free amino acids by marine net zooplankton are a positive function of water temperature and can be estimated by the equation R = T − 6.0, where R = release rate in mg α‐amino N g−1 day−1, = temperature (°C), and 6.0 is a constant. Most of the common protein amino acids are present in release products. Glycine, taurine, and alanine usually predominate. It is estimated that in an “average” water column net zooplankton release an amount of total dissolved amino acids equal to the amount in solution in about one month.
TEMPERATURE AND SALINITY EFFECTS ON CALCIFICATION RATE IN MYTILUS EDULIS AND ITS PALEOECOLOGICAL IMPLICATONS1
Authors: Malone Philip G. , Dodd J. Robert
Published: March 2010

Radioisotopic tracer experiments utilizing 45Ca reveal that calcification in the bivalve Mytilus edulis occurs over the range of 5–23.5C at 32.0‰ salinity. Specimens deposited shell over the salinity range of 20–37% at 18.5C. No upper temperature or salinity thresholds were found. Calcification rate varies directly with temperature and salinity and among individuals grown at a single temperature over the 24‐hr period of these experiments, probably because of the discontinuous nature of the calcification process. Paleo‐temperature and paleosalinity determinations, such as by oxygen isotopic composition, of the total M. edulis skeleton would yield results higher than the mean temperature and salinity for the growth locality. Measuring growth in fossil M. edulis shells might be used to determine paleotemperatures and paleosalinities. Determining the number of days in a year in the geologic past on the basis of molluscan skeletal structure is probably not possible.
VERTICAL MIGRATION AND AVOIDANCE CAPABILITY OF EUPHAUSIIDS IN THE CALIFORNIA CURRENT
Authors: Brinton Edward
Published: March 2010

Comparisons of day and night vertical distributions of euphausiids at the same stations make it possible to estimate 1) the extent of vertical migration of the furcilia, juveniles, and adults of the Euphausiacea (Crustacea) species, or 2) their ability to avoid the net in the daytime, or both. Seven species of Euphausia and one of Thysanopoda migrated more than 300 m, rising to near the surface at night. Adults of Nematoscelis (three species) migrated vertically but were bounded at upper limits by the thermocline at all but the most inshore stations. Nyctiphanes simplex and Stylocheiron carinatum were short‐distance (ca. 150–0 m) migrants. The extent of vertical migration was greatest in the most offshore central water, intermediate for midcurrent species, and least for coastal.

Nonmigrants included all Stylocheiron species (except S. carinatum), Thysanoessa gregaria, and two Nematobrachion species. S. affine, S. suhmi, and T. gregaria inhabited the homogeneous layer. Apparent increases with depth in their daytime densities arise from avoidance of nets in the upper layers. This is minimal at ca. 100 m, where day and night densities are nearly equal.
EFFECTS OF ENVIRONMENTAL CONDITIONS ON THE RATE OF PHOTOSYNTHESIS AND SOME PHOTOSYNTHETIC ENZYMES IN DUNALIELLA TERTIOLECTA BUTCHER1
Authors: Hellebust Johan A. , Terborgh John
Published: March 2010

Exponentially growing Dunaliella tertiolecta raised under continuous light increased both in photosynthetic capacity and in the activities of two enzymes of the photosynthetic reductive pentose cycle during the first 24 hr after transfer to complete darkness at 18C. A rapid decrease in photosynthetic capacity and enzyme activities followed. Three days after transfer to darkness, the photosynthetic capacity was only 25% of the initial value, while the corresponding figures for RuDP carboxylase and aldolase activities were 25 and 20%.

Decline of these metabolic parameters at 18C was greatly delayed by continuous illumination of 20 µw/cm2, an intensity considerably below the compensation point. After seven days, the photosynthetic capacity was still 78%, and the RuDP carboxylase and aldolase activities were 65 and 40% of their initial values. The same light intensity at a lower temperature (5C) almost entirely eliminated the decrease in photosynthesis and enzyme activities over a 21‐day period.

Changes in RuDP carboxylase activity followed closely those in the rate of photosynthetic dark reactions. Parallel changes in the rate of light reactions suggest that the changes in the dark and light systems are interdependent.

Light quality studies indicate that light absorbed by photosynthetic pigments is primarily responsible for decreasing the rate of loss of photosynthetic capacity and RuDP carboxylase activity. It is suggested that light of low intensity, as well as low temperature, may be ecologically important in maintaining the photosynthetic capacity of plankton algae when they are removed from the euphotic zone for a considerable length of time through sinking or vertical mixing.
UNUSUAL MONOMIXIS IN TWO SALINE ARIZONA PONDS1
Authors: Cole Gerald A. , Whiteside Melbourne C. , Brown Robert J.
Published: March 2010

Red Pond and Green Pond are shallow, saline pools in Apache County, Arizona, that stratify chemically during winter and circulate in midsummer. Stability is brought about by addition of dilute runoff and seep water to the surfaces; circulation occurs because evaporation increases the salinity of the upper waters and lowers the pond surfaces. Isothermy, dichothermy, mesothermy, and poikilotherny occur during the year. Winter stabilities are in excess of 200 g‐cm/cm2 in spite of anomalous temperature profiles and the shallow nature of the ponds.

The waters are chloro‐carbonates derived by concentration from dilute waters relatively high in sulfate and carbonate. At the overturn, Red Pond and Green Pond have salinities of 22% and 11%. Phosphate concentrations are remarkably high—up to 500 mg/liter in Red Pond.

Ctenocladus circinnatus is present in both ponds; this may be the fourth North American record for this green alga.
SEDIMENTATION IN CAYUGA LAKE, NEW YORK1
Authors: Ludlam Stuurt D.
Published: March 2010

The sediments in the southern half of Cayuga Lake are generally banded. The couplets are ca. 2 cm thick at a depth of 1.5 m in the sediment and contain finer laminae approximately 1 mm thick. Major bands can be correlated over a distance of 19 km and apparently correspond to recorded periods of unusually rapid runoff or high lake levels. It is concluded that the deposition of the couplets is controlled by annual variation in the supply of allochthonous organic detritus and clastic sediment. A total of 2 × 1011 g dry weight of clastic sediment enters the lake annually through its tributaries. Turbidity currents apparently are responsible for the distribution of a large fraction of this material in the lake.
FURTHER OBSERVATIONS INCONSISTENT WITH THE HYPOTHESIS THAT THE MOLYBDENUM BLUE METHOD MEASURES ORTHOPHOSPHATE IN LAKE WATER1
Authors: Rigler F. H.
Published: March 2010

The results of three different observations can be explained by postulating that the concentration of inorganic phosphate in lake water is much lower than indicated by the molybdenum blue test. Hydrolysis of organic phosphorus compounds is suspected to be a source of error.
THE PARTIAL EQUIVALENT CONDUCTANCES OF SALTS IN SEAWATER AND THE DENSITY/CONDUCTANCE RELATIONSHIP
Authors: Connors Donald N. , Weyl Peter K.
Published: March 2010

The partial equivalent conductances of the major salts in seawater have been determined over the temperature range from 0 to 25C and the salinity range from 30 to 35.6‰. The partial equivalent conductance data, together with published data on partial equivalent volumes, have been used to evaluate changes in the density/conductance relationship resulting from changes in the relative composition of seawater.
OXYGEN CONSUMPTION IN DIAPTOMUS
Authors: Comita Gabriel W.
Published: March 2010

The oxygen consumption of fed and unfed Diaptomus siciloides, D. oregonensis, D. leptopus, and D. clavipes was measured at five different temperatures using a micro‐Winkler technique. Regression relationships between log oxygen uptake and each of the following independent variables, temperature, log length, and log weight, as well as the combinations of temperature and length and of temperature and weight, were examined for the four species mentioned and Diaptomus arcticus and Mixodiaptomus laciniatus. The simple regression of log oxygen consumption on log dry weight at the five temperatures and the multiple regression of log oxygen consumption on temperature and log dry weight gave close approximations to the experimental means.
SEDIMENTATION IN THE ESTUARY OF THE RIVER CROUCH, ESSEX, ENGLAND
Authors: Sheldon R. W.
Published: March 2010

The coast of Essex is bordered by marshland and is subsiding. Under natural conditions sedimentation on the marshes keeps pace with subsidence, but where the land has been reclaimed and embanked, subsidence has continued with no compensating sedimentation.

Material in suspension is flocculated and is mainly inorganic but may contain up to 25% organic material. Particle diameters of the flocculi range from less than 1 µ to about 80 µ with a mean at about 10–15 µ. The concentration varies with state of tide, depth, and location. There is more material near the bottom than at the surface, and greater concentrations occur near the mouth than near the head of the estuary.

Bottom deposits are made up of two distinct particle populations. There is a fine sand fraction which is believed to be transported near the bottom, and a silt fraction derived from suspension. Offshore, in areas exposed to wave action, there arc fine sands with very little silt. The proportion of silt increases and the modal diameter of the fine sand fraction decreases towards the head of the estuary.

The sediments may be derived from offshore deposits of boulder clay, and evidence was found to suggest that these deposits are being eroded by tidal currents. Material eroded from an unsorted boulder clay could produce the distribution of sedimentary properties found in the Essex estuaries.
THE RELATIVE CONTRIBUTION OF PARTICULATE CHLOROPHYLL AND RIVER TRIPTON TO THE EXTINCTION OF LIGHT OFF THE COAST OF OREGON1
Authors: Small Lawrence F. , Curl Herbert
Published: March 2010

Extinction coefficients and chlorophyll a concentrations were measured for three years along sampling lines off the mouth of a large river (Columbia), a relatively small river (Yaquina), and a section of Oregon coastline with little river outflow. The relative contribution of particulate chlorophyll and nonliving suspended matter (tripton) to the extinction coefficient, k, was assessed using a three‐component equation that allowed the separation of areas and seasons in which k was a function of chlorophyll concentration from areas and seasons in which other factors besides chlorophyll concentration were involved.

The effect of river discharge into the sea is twofold: to increase tripton turbidity, and thus k, and to change the oceanic relationship between chlorophyll a concentration and k in areas subject to, but not overwhelmed by, river discharge. The first effect is more pronounced with large volumes of discharge and becomes less significant with increasing distances from the river mouth. Beyond the areas of masking of this relationship by tripton turbidity, k apparently is a function of chlorophyll concentration only in winter and spring (through mid‐May) when river discharge is low. In areas that never receive significant river discharge, k is a function of chlorophyll concentration during all seasons except possibly summer, when upwelling may at times destroy the relationship.
THE ECOLOGICAL SIGNIFICANCE OF FINE PARTICLE SELECTION BY THE STRIPED MULLET MUGIL CEPHALUS1
Authors: Odum William E.
Published: March 2010

By tracer experiments using 32P and a comparison of sediment and stomach content particle sizes, Mugil cephalus Linnaeus is shown to prefer very fine particles wherever sediments are involved in feeding. It is suggested that these small inorganic and plant detrital sediment particles are much richer both in absorbed organic material and in adsorbed bacteria, Protozoa, and other microorganisms than the coarser material that the mullet rejects. This selectivity results in substantially higher organic values of the stomach contents than of the sediments.
DISTRIBUTION OF THE LARVAE OF PLEURONCODES PLANIPES IN THE CALIFORNIA CURRENT
Authors: Longhurst Alan R.
Published: March 2010

Zoeae and megalopas of Pleuroncodes planipes Stimpson were found in 483 of 2,546 plankton samples from the California Current in 1957 and 1959. Their distribution in the samples showed that 1) breeding occurred during winter, mostly in February and March; 2) while some breeding could be ascribed to offshore pelagic adults, the greatest larval concentrations were over the continental shelf, often only in the presumed presence of benthic adult populations; 3) breeding extended far to the north of the usual range in the warm years centered around 1959, though it was probably not successful in the extreme north; and 4) there was clear evidence of late zoeae and megalopas being carried offshore in accordance with known geostrophic flow patterns so that at least a high proportion of megalopas had the possibility of changing to the benthic phase only after an excursion into oceanic regions. The data cannot be used to decide whether 5) any of these megalopas do, in fact, achieve a return to the coast or whether 6) any megalopas descend directly into the benthic phase after metamorphosis over the continental shelf.
BENTHIC AND LIMNETIC DISTRIBUTION OF THREE CHAOBORUS SPECIES IN A SOUTHERN MICHIGAN LAKE (DIPTERA, CHAOBORIDAE)
Authors: Roth James C.
Published: March 2010

The benthic and limnetic distributions, and size‐frequency, of the overwintered larval populations of three Chaoborus species, C. punctipennis (Say), C. albatus Johnson, and C. flavicans (Meigen) in Frains Lake, Michigan, were investigated on three dates in May and June 1965. The three species made up 91, 3, and 6% of the Chaoborus fauna. Little overlap in total length was found between species. C. flavicans tended to be concentrated in deeper benthic zones during the day than C. punctipennis. C. albatus, but not the other two species, underwent an adlittoral benthic migration. All three species migrated into the limnetic zone at night, but none reached the surface. Most limnetic C. punctipennis larvae were found higher in the water column than C. flavicans larvae.

The larvae of C. albatus were stunted, showed late growth, and may have been unable to avoid competition with larvae of the closely related C. punctipennis. Differences in distribution and morphology between C. flavicans and C. punctipennis, although slight, help to explain the apparent lack of competitive exclusion in this genus.
ESTIMATES OF THE LATENT AND SENSIBLE HEAT FLUX FOR THE CARIBBEAN SEA AND THE GULF OF MEXICO1
Authors: Hastenrath Stefan L.
Published: March 2010

Monthly mean values of the latent and sensible heat flux at the sea‐air interface (Qe + Qs) are derived for the areas of the Caribbean Sea and the Gulf of Mexico, separately: 1) from the multiannual mean of the oceanic heat budget; 2) from the atmospheric energy budget, on the basis of the available radiosonde data for the entire year 1960; and 3) by the bulk‐aerodynamic method, using 1960 ship observations.

The annual average of the latent and sensible heat transfer in the area of the Central American Seas is of the order of 270 ly/day. Making allowance for the propagation of errors and the different time periods used, the results of the three independent approaches are in fair agreement. The shortcomings inherent in all the procedures make various independent approaches desirable wherever possible.
SULFUR METABOLISM AND SEDIMENTARY ENVIRONMENT: LAKE MENDOTA, WISCONSIN
Authors: Nriagu Jerome O.
Published: March 2010

The forms and distribution of sulfur in the black bottom muds of Lake Mendota have been determined and the data combined with available background information to gain understanding of sulfur metabolism in a freshwater sulfuretum and of the generic relationships among various forms of sulfur.

The suite of sulfur compounds in the lake sediments is made up of sulfide dissolved in the interstitial water, acid‐volatile sulfide, elemental sulfur, organic sulfur, and sulfates. The dominant form of sulfur in the sludge is a black, amorphous, acid‐soluble substance believed to be hydrotroilite. No pyrite or marcasite was isolated from these bottom muds. Nearly 45% of the sulfur precipitated as sulfide is apparently derived from mineralization of organic matter with the remaining fraction coming from bacterial reduction of sulfates. The sulfur analyses coupled with other evidence suggest that prior to the change in sedimentation in Lake Mendota associated with human activity the lake had developed an oxygen deficiency intense enough to cause the reduction of sulfates to sulfides but was able to maintain its basin free of black muds by processes of self‐purification.