bluuebunny/crossref_metadata_2025 huggingface dataset:
Geochemical processes controlling concentrations of Al, Fe, and Mn in Nova Scotia lakes
Authors: Urban Noel R. , Gorham Eville , Underwood John K. , Martin Frank B. , Ogden J. Gordon
Published: April 2010

Concentrations of Al, Fe, Mn, major ions, and dissolved organic C (DOC) were measured in 37 lakes in Halifax County, Nova Scotia, to determine the factors controlling the behavior of these metals in acidic waters with relatively high concentrations of organic matter. Concentrations of trace metals ranged from <50 to 700 µg liter−1 (Al), <20 to 960 µg liter−1 (Fe), and <10 to 240 µg liter−1 (Mn). Concentrations of Fe and Al were highly correlated with H’ ion and DOC concentration, whereas Mn was correlated most strongly with H+ ion concentration and size of catchment relative to lake surface area. Computation of trace‐metal speciation indicated that lakes with pH > 5 were in equilibrium with gibbsite and amorphous iron hydroxide but highly supersaturated with respect to manganite and Mn(IV) oxides. Concentrations of Mn appear to be determined by the magnitude of the source (i.e. the catchment area) relative to the size of the lake. In lakes with pH < 5, concentrations of Al and Fe seem to be regulated by interactions with DOC. Although the metals and organic C enter the lake separately, we propose that precipitation of metal humates is the major process regulating concentrations of Al and Fe and, to a lesser extent, DOC in these lakes.
The effect of food concentration, body size, and environmental oxygen tension on the growth of the deposit‐feeding polycheate, Capitella species 1
Authors: Forbes Thomas L. , Lopez Glenn R.
Published: April 2010

This study investigates the separate and interactive effects of food concentration, environmental oxygen level, and body size on the growth rates of Capitella species 1 individuals. Reduction of environmental pO2 or food concentration decreased the volume‐specific growth rates of both large (>1.3 mm3; >1.6 mg wet wt, WW) and small (<1.0 mm3; <1.1 mg WW) worms. Within the high‐food treatments a reduction in environmental pO2 from ∼130 to 35 mm of Hg decreased the growth rates of worms by up to 36% d− 1.

Growth of large worms decreased in response to reductions in either pO2 or food concentration. The growth rates of small worms decreased significantly only in response to reductions in environmental pO2 levels. Reductions in either food concentration or environmental oxygen level alone decreased the growth of large worms to the same extent as a concomitant decrease in both. When worms were fed 100% natural sediment, a reduction in average O2 tension from 38 to 21 mm of Hg decreased the growth of large worms from 2% d−1 to −25% d−1. The growth rates of small individuals were unaffected (−4 to −3% d−1).

We predict that under conditions of near‐bottom hypoxia or food limitation (e.g. complete pelletization of ingestible sediment) populations of Capitella sp. 1 will experience size‐dependent growth with large animals (>1.6 mg WW) experiencing the greatest decline in growth rate.
Sulfur cycling in a cedar‐dominated, freshwater wetland
Authors: Spratt Henry G. , Morgan Mark D.
Published: April 2010

Rates of reduced sulfur production and quantification of S pools in anoxic peat of a New Jersey cedar swamp were determined over a 9‐month period. Short‐term anoxic incubations with 35SO42− as a tracer produced not only labeled reduced inorganic S (RIS) compounds (e.g. H2S, FeS, and FeS2), but also labeled reduced organic S, C‐bonded sulfur (CBS), compounds. The rate of production of CBS compounds averaged 59% of the production of RIS compounds. Peat S pools for the top 10 cm were dominated by CBS (74% of total S), with RIS and ester sulfates each averaging only ∼13% of the total S. In the top 10 cm of peat, rates of reduced S production were very high relative to pool sizes, indicating that recycling of S in the peat is quite rapid. The high degree of recycling made detection of reduced S accumulation in the peat impossible over the 9‐month sampling period. Our data support an important role for SO42− reduction, however, in the retention of S in the cedar swamp of McDonalds Branch.
Control of marine fish production
Authors: Iverson Richard L.
Published: April 2010

In the trophic‐dynamic hypothesis, biomass production was assumed limited by factors that control energy transfer. An analysis using trophic‐dynamic models applied to ocean data, however, leads to a rejection of that hypothesis and supports a hypothesis that carnivorous fish production is controlled by the amount of new N annually incorporated into phytoplankton biomass and transferred through food webs. For an average 2.5 trophic transfers from phytoplankton to fish in environments ranging from oceanic to northeast North American coastal waters, N transfer efficiency was a constant 0.28 while C transfer efficiency increased nonlinearly from 0 to an asymptotic value of 0.16. Fish production was more sensitive to variations in phytoplankton production in oligotrophic than in eutrophic marine environments as a result of a nonlinear decrease in f, the ratio of new to total production, as primary production decreased.
A year‐long observation of water exchange between the North Pacific and the Bering Sea
Authors: Reed R. K.
Published: April 2010

Knowledge of the exchange of waters between the North Pacific Ocean and Bering Sea is limited because of the lack of reliable measurements. Existing estimates of flow through the major pass (Amchitka) in the Aleutian Islands were disparate and based on short‐term data. A 1‐yr series of direct current measurements was obtained in this pass, which revealed a northward flow of warm Alaskan Stream water into the Bering Sea. An estimate of volume transport gave 2–3 × 106 m3 s−1, which is 10–15% of the transport of the Alaskan Stream.
Temperature and annual cycle of nitrification in waters of Narragansett Bay.
Authors: Berounsky Veronica M. , Nixon Scott W.
Published: April 2010

Pelagic nitrification, measured over an annual cycle at two sites in Narragansett Bay, Rhode Island, was strongly correlated with temperature. At a nutrient‐poor site, rates ranged from near zero in winter to almost 1 µmol N liter−1 d−1 in summer, with an apparent Q10 of 6.8. Rates were always higher at a nutrient‐rich Providence River estuary site, with a summer maximum >11 µmol N liter−1 d−1 and an apparent Q10 of 17.6. Laboratory experiments that examined the response of nitrification to temperature alone resulted in a Q10 of 7.5. The high summer rate of nitrification was balanced by NO3− uptake by phytoplankton. Elevated levels of NO3− in fall resulted from a marked decline in phytoplankton uptake and a continuing slow rate of nitrification and were not dependent on river inputs. Other N transformations do not respond to temperature as strongly as nitrification did, thus temperature increases may effect the distribution of N.
Food limitation and benthic regulation of populations of the copepod Acartia hudsonica Pinhey in nutrient‐limited and nutrient‐enriched systems
Authors: Sullivan Barbara K. , Banzon Patria V.
Published: April 2010

Evidence that population size of copepods in coastal marine systems can be both resource and predator limited was obtained from experimental enclosures with and without the sediment community in place. The novel finding was that meroplankton and attached benthos were apparently effective competitors and predators of planktonic copepods in both nutrient‐limited and nutrient‐enriched systems. During the spring period of increase Acartia hudsonica, as well as other abundant species of copepods, reached considerably higher numbers in four mesocosms without sediments than in four other mesocosms with the normal sediment community in place regardless of rate of nutrient input to the mesocosms. Measurements of population parameters of A. hudsonica indicated equivalent rates of reproduction, growth, and recruitment in nutrient‐enriched treatments with and without sediments. Suppression of population growth in the presence of sediments was therefore not due to food limitation but, by inference, to higher rates of mortality associated with high abundances of potential predators of benthic origin. In unenriched control mesocosms, resource competition with the benthos may also have contributed to low population densities in tanks with sediments (reproductive rates were more food limited in enclosures with sediment that in those without sediment). These results demonstrate important interactions between benthic and pelagic fauna that have often been overlooked but nevertheless may be important in regulating dynamics of pelagic copepod populations in shallow, well‐mixed waters.
Vertical migration of Chaoborus larvae is induced by the presence of fish
Authors: Dawidowicz Piotr , Pijanowska Joanna , Ciechomski Konrad
Published: April 2010

Diel changes in the depth distribution of Chaoborus flavicans larvae in thermally stratified aquaria with a distinct light gradient revealed that the larvae responded behaviorally to the presence of fish. Both the midday and midnight mean depths of the population were greater in the presence of fish. Most fish‐treated larvae found a daily refuge in bottom sediments. It appears that the stimulus for vertical migration is chemical, not visual or mechanical. The fish effect persisted for more than 15 d but was reversible. Those individuals that previously had been exposed to fish factor were considerably more sensitive to light than untreated larvae and showed a panic response when suddenly illuminated.
Microdistribution and diel vertical migration of flagellated vs. gas‐vacuolate purple sulfur bacteria in a stratified water body
Authors: AliÓ Carlos Pedrbs‐ , Sala Ma. Montserrat
Published: April 2010

The diel vertical distribution of purple sulfur bacteria was followed in Lake Cisó. A syringe system provided simultaneous samples every 3 cm. One of the bacteria, Chromatium minus, was flagellated and showed vertical migration of 35 cm. This daily excursion was enough to maintain itself in the uppermost anaerobic part of the metalimnion. The swimming speeds necessary to explain such migration were within the range of values previously recorded for these bacteria in the field. The other bacterium, Amoebobacter M3, had gas vesicles but did not seem to move vertically. Thus, vertical migration by a planktonic bacterium was demonstrated in nature.
A simple spectral solar irradiance model for cloudless maritime atmospheres
Authors: Gregg Watson W. , Carder K. L.
Published: April 2010

A simple spectral atmospheric radiative transfer model specific for oceanographic applications begins with spectral extraterrestrial solar irradiance corrected for earth‐sun orbital distance. Irradiance is then attenuated in passing through the atmosphere by Rayleigh scattering, ozone, oxygen, and water vapor absorption, and marine aerosol scattering and absorption, and is finally reduced by reflectance at the air‐sea interface. The model is an extension of the continental aerosol model of Bird and Riordan, modified to include maritime aerosol properties, irradiance transmittance through the air‐sea interface, and atmospheric absorption at very high spectral resolution (1 nm). Atmospheric optical constituents and the surface reflectance are functions of the local meteorological conditions, imparting flexibility to the model to reproduce the spectral irradiance under a variety of maritime atmospheres. The model computes irradiance at or just below the ocean surface at high spectral resolution in the range 350–700 nm, i.e. within the range required for photosynthetically available radiation (PAR) calculations. It agrees spectrally with observed surface spectral irradiances to within ±6.6% (rms) and as integrated PAR to within ±5.1%. The computed spectral irradiance is useful as an input to bio‐optical models in the ocean, to phytoplankton growth and primary production models, and in remote‐sensing applications.
Convective motions in the sidearm of a small reservoir
Authors: Monismith Stephen G. , Imberger Jörg , Morison Michael L.
Published: April 2010

We present observations of the diurnal formation of horizontal temperature gradients in the surface waters of a sidearm of a small water supply reservoir at a time during summer when radiative heating and vertical stratification of the reservoir’s waters were both quite strong. Our measurements show that because the closed end of the sidearm was relatively shallow, daytime heating and nighttime cooling created larger temperature changes there than in the body of the lake, resulting in large horizontal temperature gradients that drove strongly sheared, horizontal exchanges. Because of more vigorous turbulent mixing during cooling, cooling‐driven flows were slower and of greater vertical extent than were heating‐driven flows. The overall flow exhibited inertia in that it was not in phase with the daily heating cycle. Averaged over the daily cycle, there appeared to be a net residual flow, with surface waters flowing out and metalimnetic waters flowing in. This thermally driven flow, the “thermal siphon,” greatly enhanced the rate of horizontal exchange between the sidearm and the body of the reservoir such that the time required to replace water in the sidearm when the siphon is operating is substantially less than estimates with conventional formulae based on horizontal turbulent diffusion.
Stable horizontal variation in the zooplankton community structure of a reservoir maintained by predation and competition
Authors: Urabe Jotaro
Published: April 2010

The zooplankton community of the Ogochi Reservoir was investigated with brief field experiments to examine the mechanisms that maintain a stable horizontal distribution of species in the warm‐water season. Daphnia galeata predominated near the dam sitc, and its abundance declined toward thc headwaters. The abundance of other species increased away from the dam, and Bosmina longirostris was found abundantly at the site near the headwaters. Demographic analysis and field experiments demonstrated that D. galeata had the potential to depress the abundance of other species through exploitative competition and to predominate at sites near the headwaters as well as at the dam site. This potential was never realized, however, at a site near the headwater because of a high mortality rate that could not be explained by food abundance or physical and chemical conditions in the water. The invertebrate predator Leptodora kindtii was abundant at sites nearer the headwaters, but its occurrence was limited temporally. Trammel gill‐net samples revealed that planktivorous fish, which prey selectively on the superior competitor D. galeata and the invertebrate predator L. kindtii, were distributed toward the headwaters in the warm‐water season. The high mortality rate of D. galeata at the site near the headwaters apparently was attributable to predation by fish. The data presented demonstrate that the pelagic environment in the reservoir is functionally heterogeneous and that species interactions play an important role in maintaining the stable horizontal pattern in the community structure.
Seasonal regulation of Daphnia populations by planktivorous fish: Implications for the spring clear‐water phase
Authors: Luecke Chris , Vanni Michael J. , Magnuson John J. , Kitchell James F. , Jacobson Paul T.
Published: April 2010

The ability of planktivorous fish to regulate the population dynamics of Daphnia galeata in Lake Mendota, Wisconsin, was examined during spring and summer 1987. Low rates of consumption by yellow perch (Perca flavescens) and cisco (Coregonus artedii) allowed populations of D. galeata to expand rapidly during spring, resulting in a distinct clear‐water period that lasted from mid‐May until early June. A subsequent decline in D. galeata abundance resulted from low food availability brought about by its exploitation of algal resources. Once populations of D. galeata were reduced, predation by perch and cisco was sufficient to keep populations of D. galeata at low densities during July and August in spite of more abundant algal food resources. Extreme seasonal variation in the degree to which planktivorous fish can regulate daphnid population dynamics may have allowed daphnids to persist in Lake Mendota during the past century in the presence of abundant zooplanktivores.
Specialist herbivores reduce their susceptibility to predation by feeding on the chemically defended seaweed Avrainvillea longicaulis
Authors: Hay Mark E. , Dufy J. Emmett , Paul Valerie J. , Renaud Paul E. , Fenical William
Published: April 2010

The tropical green seaweed Avrainvillea longicaulis is a low preference food for coral‐reef fishes, and it produces a brominated diphenylmethane derivative called avrainvilleol that significantly deters feeding by reef fishes in field bioassays. In contrast to the pattern for fishes, the ascoglossan gastropod Costasiella ocellifera and the crab Thersandrus compressus live on and eat only Avrainvillea. The gastropod sequesters avrainvilleol from its algal host and uses this compound as an effective defense against predatory fish. The crab does not sequester chemical defenses; however, it is camouflaged when on Avrainvillea and thus also experiences less predation when associated with this alga. Specialization on this chemically defended seaweed allows Costasiella to deter and Thersandrus to avoid predation. When coupled with other recent studies of specialist marine herbivores, these findings suggest that predator avoidance and deterrence are major advantages associated with the evolution of feeding specialization among herbivorous marine invertebrates.
Bacterial production on humic and nonhumic components of dissolved organic carbon
Authors: Moran Mary Ann , Hodson Robert E.
Published: April 2010

Dissolved humic substances make up ∼50% or more of the dissolved organic carbon (DOC) in freshwater ecosystems, yet their trophodynamic roles remain unresolved. We separated DOC from two freshwater environments, a lake and a blackwater marsh, into two fractions, humic DOC and nonhumic DOC, using an XAD‐8 resin to selectively adsorb the humic substances. Results of microcosm studies revealed that the humic fraction of DOC was used by natural bacterial assemblages from the lake and marsh as a C and energy source, as indicated both by increases in bacterial biovolume and rates of bacterial incorporation of [3H]thymidine. Humic substances supported fourfold less bacterial secondary production per unit of initial C, however, than did nonhumic substances from the same environment. Bacterial utilization of humic compounds accounted for a significant fraction of the total bacterial production on DOC, measured as increases in bacterial biovolume; humic substances supported an average of 22% of total growth on DOC from the lake and 53% of the total growth on DOC from the marsh. The relative bioavailability of both the humic and nonhumic fractions of DOC differed between the lake and blackwater marsh, with less bacterial production per unit of initial C occurring on marsh‐derived dissolved compounds.
Field measurement of specific growth rate, biomass, and primary production of benthic diatoms of Savin Hill Cove, Boston
Authors: Gould Diane M. , Gallagher Eugene D.
Published: April 2010

14C‐labeling of chlorophyll a and subsequent extraction by high‐pressure liquid chromatography (HPLC) was adapted for field measurement of both specific growth rate and biomass of diatom films found on muddy intertidal sediments of Savin Hill Cove, a small embayment of northwest Dorchester Bay, Boston Harbor. Primary production was measured concurrently via 14C uptake into total cellular C. An incubation apparatus that incorporates stirring to enhance sediment‐water gas exchange was used at both low and high tides. Over the year‐long study period (August 1987–August 1988) measured specific growth rates were low (0.06–0.27 d−1) while biomass estimates were high (2.21 × 10−4 to 1.54 × 10−3 g C cm−2). C : Chl ratios varied from 18.7 to 60.4. The highest biomass values and C : Chl ratios were found during the 1988 spring bloom. The very low specific growth rates measured during the spring bloom (0.06 and 0.09 d−1) coupled with spring increases in the numbers of grazers may explain the steep decline in biomass that followed the spring bloom in 1986–1988.
Twentieth‐century salinity and water‐level fluctuations in Devils Lake, North Dakota: Test of a diatom‐based transfer function
Authors: Fritz Sherilyn C.
Published: April 2010

Diatom surface‐sediment assem blages and associated water‐chemistry data are used to develop a transfer function for the quantitative reconstruction of salinity change in the northern Great Plains of North America. The transfer function, derived from canonical correspondence analysis (CCA) of the surface‐sample data, is applied to a core from Devils Lake in sediments encompassing the last century. The accuracy of the calibration equation is tested by comparing the diatom‐inferred salinity with documented salinity and water‐level data recorded for the lake over the last 100 yr. The diatom‐based reconstruction shows good agreement with the historical data, particularly in freshwater and at low to moderate salinities. Discrepancies between the measured and diatom‐inferred salinity during high‐salinity periods may reflect inadequacies with the inference method itself or more likely problems in the sedimentary record of the lake related to poor diatom preservation, sediment mixing and reworking, and dating inaccuracies. This diatom‐based inference method for salinity reconstruction represents a powerful tool for paleohydrologic and paleoclimatic reconstruction in semiarid and arid regions.
Nitrogenase activity of Microcoleus lyngbyaceus mat communities in a eutrophic, tropical marine environment
Authors: Diaz Mara R. , Corredor Jorge E. , Morell Julio M.
Published: April 2010

Floating and attached cyanobacterial mats consisting primarily of Microcoleus lyngbyaceus, a nonheterocystous, filamentous cyanobacterium, are a permanent feature of the nearshore marine environment at La Parguera, Puerto Rico. Nitrogenase activity in these mat communities, as determined by acetylene reduction, exhibited a diel cycle with daytime inhibition and enhanced nocturnal activity. Contrary to reports regarding benthic cyanobacterial mats adapted to oligotrophic conditions, nitrogenase activity in M. lyngbyaceus mats is closely regulated by concentrations of NH4+ and NO3− within the range of values common to their environment. The opportunistic strategy of N utilization used by M. lyngbyaceus, whereby molecular N is primarily consumed only in the absence of significant concentrations of alternate inorganic N sources, assures the success of these cyanobacterial mat communities.
Effect of light on oxygen and carbon dioxide fluxes and on metabolic quotients measured in situ in a zooxanthellate coral
Authors: Gattuso J.‐P. , Jaubert J.
Published: April 2010

Oxygen and CO2 fluxes were measured in situ as a function of depth on colonies of two species of the zooxanthellate coral Stylophora and were used to compute metabolic quotients. We report for the first time on the photosynthetic quotient of zooxanthellae in hospite (PQz); it ranges from 1.14 to 1.57 and depends on the light regime (daily photosynthetic photon flux density). The comparative effect of light on PQz and on the respiratory quotient of the coral suggests that glycerol is the main substance photosynthesized, translocated, and consumed in shallow‐water colonies, whereas it is replaced by lipid with decreasing light (increasing depth). Such a result is potentially important for the energy budget considerations of any plant‐animal endosymbiosis and provides some evidence that light controls the quality of products photosynthesized by the plant and catabolized by the host.
Artifacts in measuring absorption spectra of phytoplankton collected on a filter
Authors: Stramski Dariusz
Published: April 2010

I show a conventional filter technique for measuring absorption spectra of phytoplankton may be subject to errors arising from rapid decomposition of pigments collected on the filter. Incorrect values of spectral absorption indicating a higher proportion of degraded pigments relative to their actual cellular concentration can be measured by this method. The sensitivity of the method to these errors appears to be species specific. A simple refinement, incorporating chemical fixation of microorganisms before filtration, is proposed as a possible means to overcome these artifacts. Inadequacy of glass‐fiber filters for retaining all absorbing particles is also suggested as a potential source of underestimation in particulate absorption measured traditionally on samples collected by filtration.
Production of dimethylsulfonium propionate (DMSP) and dimethylsulfide (DMS) by a microbial food web
Authors: Belviso S. , Kim S.‐K. , Rassoulzadegan F. , Krajka B. , Nguyen B. C. , Mihalopoulos N. , Buat‐Menard P.
Published: April 2010

Production and decomposition of DMSP and DMS in a microbial food web were investigated by means of a 5‐d incubation of prescreened seawater samples (<1, <10, <100 µm) from northwestern Mediterranean coastal waters. The major goal of size fractionation was to create predator‐free compartments. Aplastidic flagellates, plastidic nanoflagellates (<10 µm), or both contributed to the particulate DMSP pool, but DMSP was found to be predominantly associated with the populations of small dinoflagellates (~20 µm, Prorocentrum sp., Gymnodinium sp.). Particulate‐DMSP values and free‐cell counts in the < 100‐µm fraction, however, were not significantly correlated. This result reflects the grazing pressure of ciliates on the DMSP carriers since significant amounts of DMSP can be stored temporarily by the microzooplanktonic predators. The initial level of soluble DMSP was 12% of the total DMSP pool of seawater and less than 2% at the end of the experiment. This result suggests that free DMSP is not produced in significant amounts by the predator‐prey interactions in the microbial food web. Conversely, DMS was shown to be excreted following ciliate grazing on dinoflagellates and DMSP decomposition. Mass balance between DMSP and DMS was achieved after a time lag of ~1.5 d. We suggest that DMSP decomposition into DMS in the marine environment can occur through microplanktonic catabolism by two pathways: enzymatic cleavage and formation of an intermediate compound after demethylation. Overall, our work indicates that microzooplankton grazing is significant in DMS release in open‐ocean, surface waters.
Diel buoyancy regulation in the marine diazotrophic cyanobacterium Trichodesmium thiebautii
Authors: Villareal Tracy A. , Carpenter Edward J.
Published: April 2010

Trichodesmium thiebautii suspension characteristics were studied in four diel cycles from the Bahamas and eastern Caribbean Sea. Positively buoyant colony frequency peaked near sunrise (69–80%), and decreased during the day to a minimum at or near sundown (18–32%). Negatively buoyant colonies varied inversely in frequency. Experimental results are consistent with carbohydrate‐ballasting mechanisms observed in limnetic cyanobacteria. Active buoyance reversals observed in Trichodesmium can account for the frequently observed subsurface maxima of Trichodesmium and may permit diel vertical migration.
Comparisons of phytoplankton biomass in temperate and tropical lakes
Authors: Lewis William M.
Published: April 2010

Phytoplankton biomass is compared for 16 temperate and 5 tropical lakes that are sufficiently deep to develop seasonal stratification. The ratio of annual mean to maximum biomass averages 0.45 for tropical lakes and is significantly lower for temperate lakes (0.36). Seasonal (3‐month peak) ratios of mean to maximum biomass (~0.7) do not differ for oligotrophic tropical and temperate lakes, but the ratios for temperate lakes fall below those of tropical lakes at higher trophic states. Tropical lakes of given trophic state have a higher minimum biomass than temperate lakes of the same trophic state; both temperate and tropical lakes show a strong increase in minimum biomass with increasing maximum biomass. The relative range of annual variation for temperate lakes is ~40% greater than for tropical lakes. Differences in the stability of layering and in the duration of seasonal mixing probably explain much of the difference in variability of biomass for tropical and temperate lakes that stratify.
Size plasticity of freshwater phytoplankton: Implications for community structure
Authors: Duarte Carlos M. , Agusti Susana , Canfield Daniel E.
Published: April 2010

A survey of 330 phytoplankton communities in Florida lakes shows the range of populations (i.e. from sparse to dense) developed by 63 phytoplankton genera to increase with increasing size plasticity of the genera. The average size of individuals within genera tended to increase as the 1/2 power of their biomass in the community, the strength and nature of these relationships depending on the potential for size plasticity of the genera. These patterns provide evidence of the important adaptative value of algal size and support the notion that algal biomass is an important vector constraining the structure of phytoplankton communities.
ESL Coteaching and Collaboration: Opportunities to Develop Teacher Leadership and Enhance Student Learning
Authors: DOVE MARIA , HONIGSFELD ANDREA
Published: April 2010

This article presents seven English as a second language (ESL) coteaching models and explores other possibilities of collaboration between general education classroom teachers, content area teachers, and ESL specialists in the K‐12 context. Through authentic case vignettes, we illustrate how collaborative experiences and coteaching opportunities can lead to the emergence of teacher leaders and enhanced student learning
Pushing Back Against Push‐In: ESOL Teacher Resistance and the Complexities of Coteaching
Authors: McCLURE GREG , CAHNMANN‐TAYLOR MELISA
Published: April 2010

As U.S. school districts struggle to address persistent achievement gaps between increasing numbers of English language learners (ELLs) and their native‐English‐speaking counterparts, many districts are moving away from segregative models like pull‐out to implement more collaborative approaches such as coteaching, or push‐in. In contrast to pull‐out, coteaching has been lauded for its good intentions of creating an inclusive educational environment by coordinating the expertise of grade‐level teachers and teachers of English to speakers of other languages into single coteaching settings. Using ethnographic and arts‐based approaches to research, this study adopts a critical perspective that challenges this unproblematic presentation of coteaching as a panacea for educating ELLs. Additionally, the study examines the potential for performance‐based focus groups (Boal, 1979) to cultivate dialogue and coalition building among coteachers of ELLs. Data from the study suggest that coteaching is a complex social act influenced by hierarchical relations of power and status in the school setting. Performance‐based focus groups reveal that language, race, and ethnicity also are implicated as important social factors in the coteaching enterprise. In the context of these demographic and instructional trends, this study offers timely insight into the challenges, complexities, and possibilities of coteaching, with clear implications for pedagogy and professional development.
Older Children Need Phonemic Awareness Instruction, Too
Authors: SZABO SUSAN
Published: April 2010

This article reports the results of a yearlong collaborative action research study conducted by a team of second‐grade teachers and two reading specialists. It was found that more phonemic awareness instruction was needed to help their older limited‐English‐proficient language learners gain the necessary graphophonemic skills needed to become successful readers.
Alcohol-Related Deaths of US Health Care Workers
Authors: Olfson Mark , Cosgrove Candace M. , Wall Melanie M. , Blanco Carlos
Published: May 2024

This cohort study investigates the risk of alcohol-related death among US health care workers compared with non–health care workers.
Foster Care and Health in Medicaid-Enrolled Children Experiencing Parental Opioid Use Disorder
Authors: Meinhofer Angélica , Chandra Nisha , Byanova Desislava , Keyes Katherine M.
Published: May 2024

Importance

The burden of the US opioid crisis has fallen heavily on children, a vulnerable population increasingly exposed to parental opioid use disorder (POUD) in utero or during childhood. A paucity of studies have investigated foster care involvement among those experiencing parental opioid use during childhood and the associated health and health care outcomes.

Objective

To examine the health and health care outcomes of children experiencing POUD with and without foster care involvement.

Design, Setting, and Participants

This population-based cohort study used nationwide Medicaid claims data from January 1, 2014, to December 31, 2020. Participants included Medicaid-enrolled children experiencing parental opioid use–related disorder during ages 4 to 18 years. Data were analyzed between January 2023 and February 2024.

Exposure

Person-years with (exposed) and without (nonexposed) foster care involvement, identified using Medicaid eligibility, procedure, and diagnostic codes.

Main Outcomes and Measures

The main outcomes included physical and mental health conditions, developmental disorders, substance use, and health care utilization. The Pearson χ2 test, the t test, and linear regression were used to compare outcomes in person-years with (exposed) and without (nonexposed) foster care involvement. An event study design was used to examine health care utilization patterns before and after foster care involvement.

Results

In a longitudinal sample of 8 939 666 person-years from 1 985 180 Medicaid-enrolled children, 49% of children were females and 51% were males. Their mean (SD) age was 10 (4.2) years. The prevalence of foster care involvement was 3% (276 456 person-years), increasing from 1.5% in 2014 to 4.7% in 2020. Compared with those without foster care involvement (8 663 210 person-years), foster care involvement was associated with a higher prevalence of developmental delays (12% vs 7%), depression (10% vs 4%), trauma and stress (35% vs 7%), and substance use–related disorders (4% vs 1%; P < .001 for all). Foster children had higher rates of health care utilization across a wide array of preventive services, including well-child visits (64% vs 44%) and immunizations (41% vs 31%; P < .001 for all). Health care utilization increased sharply in the first year entering foster care but decreased as children exited care.

Conclusions and Relevance

In this cohort study of Medicaid-enrolled children experiencing parental opioid use–related disorder, foster care involvement increased significantly between 2014 and 2020. Involvement was associated with increased rates of adverse health outcomes and health care utilization. These findings underscore the importance of policies that support children and families affected by opioid use disorder, as well as the systems that serve them.
Adolescent Neurodevelopmental Variance Across Social Strata
Authors: Bottenhorn Katherine L. , Cardenas-Iniguez Carlos , Schachner Jared N. , Rosario Michael A. , Mills Kathryn L. , Laird Angela R. , Herting Megan M.
Published: May 2024

This cohort study explores variability in neurodevelopment across sociodemographic factors among youths.
Ethylene Glycol Co‐Solvent Enables Stable Aqueous Ammonium‐Ion Batteries with Diluted Electrolyte
Authors: Fei Huifang , Yang Fuhua , Jusys Zenonas , Passerini Stefano , Varzi Alberto
Published: May 2024

Aqueous ammonium‐ion batteries (AAIBs) are considered as one of the most promising technologies for large scale energy storage applications, due to their intrinsic safety, environmental friendliness and low cost. Nevertheless, the practical application of AAIBs is impeded by hydrogen evolution reaction (HER) occurring in diluted aqueous electrolyte. Highly concentrated electrolytes can improve electrochemical stability but lead to higher costs and increased hydrolysis of NH4+. In this work ethylene glycol (EG) is proposed as co‐solvent, which can act as H‐bond modulating agent, to increase the stability of AAIBs with diluted electrolytes. The perturbation of water H‐bond network regulated by EG is proved by spectroscopic methods, while the suppressed HER is confirmed by differential electrochemical mass spectrometry (DEMS) results. As a result, full cells with 3,4,9,10‐perylenebis(dicarboximide) (PTCDI) anode and FeFe(CN)6 (FeHCF) cathode and EG‐added electrolyte exhibit stable cycling performance with capacity retention of 77% after 1950 cycles.
One‐dimensional phenanthroline‐based covalent organic framework bearing single cobalt atoms for efficient photocatalytic CO2 reduction
Authors: Ai Lv‐Ye , Wang Qian , Chen Xiao‐Wen , Jiang Guo‐Fang
Published: May 2024

Metalated covalent organic frameworks (COFs) for 2D and 3D topologies are continuously being developed, whereas metalated COFs with 1D topologies are still in their infancy. Here, a novel 1D phenanthroline‐based COF containing 4,4‐(1,10‐phenanthroline‐2,9‐diyl)bis[benzaldehyde] (PBA) is reported (PAD‐COF). Subsequently, a metalated 1D COF, Co SAS/PAD‐COF, is constructed using the bidentate ligand properties of PBA and anchoring the single Co atoms in PAD‐COF through a post‐synthetic modification strategy. This complex significantly improved the photocatalytic performance of PAD‐COF, and the CO yield of the optimized Co SAS/PAD‐COF was stable at 3091 µmol g−1 h−1 with a selectivity of 93%, which is approximately 43.7 times that of the original PAD‐COF. Experimental and theoretical results demonstrate the excellent CO2 photoreduction activity of Co SAS/PAD‐COF owing to the synergistic effect of single Co catalytic sites and PAD‐COF. Among them, PAD‐COF, as the host, adsorbs CO2 molecules and loads single Co atoms. Meanwhile, Co atoms function as catalytic sites and promote the adsorption and activation of CO2, while reducing the reaction energy barrier formed by the *COOH intermediates. Therefore, this unique metalated 1D COF provides a fresh approach to photocatalytic CO2 reduction.
Open‐source stand‐alone version of atmospheric model Aeolus 2.0 software
Authors: Rostami Masoud , Petri Stefan , Guimaräes Sullyandro Oliveira , Fallah Bijan
Published: May 2024

In this discourse, we present the unveiling of an open‐source software package designed to facilitate engagement with the atmospheric model, Aeolus 2.0. This particular iteration stands as a self‐contained model of intermediate complexity. The model's dynamical core is underpinned by a multi‐layer pseudo‐spectral moist‐convective Thermal Rotating Shallow Water (mcTRSW) model. The pseudo‐spectral problem‐solving tasks are handled by the Dedalus algorithm, acknowledged for its spin‐weighted spherical harmonics. The model captures the temporal and spatial evolution of vertically integrated potential temperature, thickness, water vapour, precipitation, and the intricate influence of bottom topography. It comprehensively characterizes velocity fields in both the lower and upper troposphere, employing resolutions spanning a spectrum from the smooth to the coarse, enabling the exploration of a wide range of dynamic phenomena with varying levels of detail and precision.
Contributions of mothers' and fathers' shared book reading with infants at 9 months to language skills at 18 months in ethnically and socioeconomically diverse families
Authors: Chen Yu , Cabrera Natasha , Sudduth Charlotte , Reich Stephanie M.
Published: May 2024

Using a sample of 286 mothers and fathers from ethnically and socioeconomically diverse backgrounds, we tested the associations between the frequency and quality of parents' shared book reading (SBR) with infants aged 9 months, and language skills of infants aged 18 months, and whether infants' attention during SBR at 9 months mediated these associations. Frequency of SBR was parent‐report and quality of SBR (i.e., number of reading strategies) and infants' attention were coded from recorded SBR interactions at home. The majority of mothers and fathers reported reading to their 9‐month‐olds at least weekly, and mothers reported reading, on average, significantly more often than fathers. There was large variability in parents' SBR quality ranging from 0 to 15 strategies per minute, with labelling being the most common. Path analysis showed that mothers' SBR frequency at 9 months was significantly associated with infants' receptive and expressive language skills at 18 months, whereas, SBR quality by either parent was not significant. Infants' attention did not mediate these associations. These findings suggest that early SBR is beneficial for language development and programmes targeting early language development should encourage both mothers and fathers to read often to their infants during the first year.
What books should we like? A study of gender differences and stereotypes in the reading behaviors of Chinese middle school students
Authors: Xiao Peng , Jin Xiyan , Sun Shaowei , Madden Andrew
Published: May 2024

Introduction

This study investigated gender differences in the reading behaviors of Chinese middle school students, and whether gender stereotypes relating to choices of reading matter are supported.

Methods

A mixed‐methods approach was adopted. Three thousand nine hundred and fifteen middle school (Grade 7) students completed a questionnaire designed to assess reading behaviors. Independent samplet‐test and chi‐square analyses were employed to examine gender differences in reading behaviors. The qualitative survey was supplemented with an open response survey (94 boys, 50 girls), which provided further insights into individuals' specific experiences and perspectives regarding reading behaviors and gender stereotypes in reading choices.

Results

This study revealed a number of gender‐linked differences. Boys spent more time reading than girls but read the same number of books; boys were also more likely than girls to read digital texts, while girls were more likely to borrow their reading material. Choice of subject matter also differed: boys were more likely to read factual and action‐based books, while girls' choices focused more on motives and emotions. Another significant difference was that boys paid more attention to the overall experience of reading, while girls paid more attention to the details of reading. Responses to the open response survey indicated that gender stereotypes in reading choices were prevalent among respondents, but some students' reading choices did not align with the stereotype associated with their gender.

Conclusion

The mixed‐methods approach proved valuable in both identifying gender differences in reading behaviors, and in highlighting the prevalence of gender stereotypes in reading choices among middle school students.
A brief mindfulness‐based intervention for stress, pain, emotion and attention regulation in military service members with mild traumatic brain injury
Authors: MacNulty William K. , Uomoto Jay M. , Peterson Seattle M.
Published: May 2024

Aim

The primary aim of this study was to conduct an open pilot clinical trial of a brief mindfulness‐based intervention for persistent postconcussion symptoms that occur after mild traumatic brain injury in military service members. For many service members, operational tempo and other time constraints may prevent them from completing a standard mindfulness‐based stress reduction course. Thus, this study sought to examine the effectiveness of a five‐session intervention called mindfulness‐based stress, pain, emotion, and attention regulation (MSPEAR).

Methods

Participants were active duty service members with a history of mild traumatic brain injury (TBI) and persisting postconcussion symptoms, all of whom were recruited from an outpatient TBI rehabilitation program at a military treatment facility. Of the 38 service members that were initially enrolled, 25 completed the 5‐session MSPEAR intervention, and 20 returned for a 5‐week follow‐up evaluation. Questionnaires assessing perceived stress, positive affect, pain interference and catastrophizing, sleep disturbances, perceived behavioral and attention regulation, self‐efficacy and satisfaction with life were administered at preintervention, postintervention, and at 5‐week follow‐up intervals. Neuropsychological testing at preintervention and 5‐week follow‐up included performance validity measures, attention, working memory, and executive function measures. T‐tests were run to compare for questionnaire measures at preintervention (Time 1) to postintervention (Time 2). Repeated analysis of variances were conducted to compare questionnaire and neuropsychological measures at Time 1, Time 2, and at Time 3 which is the 5‐week follow‐up.

Results

Improvements in perceived stress, positive affect, behavioral regulation, metacognition, sleep disturbance, self‐efficacy, and satisfaction with life were found immediately after the MSPEAR intervention and were maintained at the 5‐week follow‐up. Magnification and helplessness aspects of pain catastrophizing improved when comparing preintervention to the 5‐week follow‐up. Pain interference was not significantly different across study assessment times. Neuropsychological testing revealed improvements in sustained attention, working memory, cognitive flexibility, and inhibitory control when comparing preintervention to the 5‐week follow‐up assessment.

Conclusions

The MSPEAR intervention appears to show promise as a brief and effective therapy for specific postconcussion symptoms after mild traumatic brain injury in military service members. Each of the components of MSPEAR including stress, pain catastrophizing, emotion and attention regulation showed improvements in this study, and bears further investigation in a larger scale, preferably randomized controlled trial in those active duty military service members who experience persisting symptoms after a mild traumatic brain injury.
Aplacophoran traits in the late Ordovician septemchitonid polyplacophorans
Authors: Dzik Jerzy
Published: May 2024

A sample of phosphatized, originally calcareous, mollusk shells from the Katian age uppermost Mójcza Limestone at its type locality yielded a few hundred polyplacophoran plates. The chelodids are very rare among them. Three septemchitonid species dominate. They represent a gradation from underived steep roof‐like plates to almost cylindrical ones, leaving only a narrow ventral slit for the foot. Apparently, this represents the first step toward the extremely derived ‘segmented clam’ Bauplan of the Silurian Carnicoleus, with plates completely closed at the venter except for the mouth and anal openings. To enable growth, the plates became thinner and more flexible (or perhaps resorbed) along the dorsum. The tendency toward reduction of the ventral gap of the plates in the early Paleozoic septemchitonid polyplacophorans implies their lack of ability to cling to the substrate with a muscular foot. In compensation, their plates changed toward a more efficient protective function, covering the animal body sides more and more completely. This may explain the origin of the ventral furrow of extant solenogasters hiding the rudimentary foot. An opposite route was chosen by the coeval Acaenoplax lineage, in which the plates did not contact each other, exposing much of the soft body on the dorsum. In both cases the animals appeared to be worm‐like, perhaps representing different ways of evolution from the Paleozoic chitons to the extant aplacophorans.