A Comparison of Photosynthetic Yields in the Maumee River, Steidtmann's Pond, and Urschel's Quarry under Natural Conditions

Author Institution: Department of Biology, Bowling Green State University, Bowling Green, OhioA study of photosynthetic rates under natural conditions in the Maumee River, Steidtmann's Pond, and Urschel's Quarry, computed from pH and O2 measurements in the natural habitat at 4- to 6-hr intervals, revealed average rates of 1.4 to 20.9 /xmol CO2 absorbed petliter of water per hour, and 0.27 to 1.32 ^mol CO2 absorbed per /xliter of plant matter per hour, with 0.1 to 35.0 /imol O2 evolved per liter of water per hour, and about 0.012 to 2.22 yumol O2 evolved per pliter of plant matter per hour. These values lie within the range of values for ponds, quarries, lakes, and streams reported in the literature. They are much lower than published values for clear flowing streams. It seems likely that poor light supplies resulting from suspended silt particles cancel any ecological advantage the turbulence of flowing water might provide. The ratios of O2 production to CO2 absorption were close to unity except during the spring flood period when ratios below 0.1 were observed, similar to ratios found in a shallow pond near Bowling Green

Airborne Temperature Survey of Harrison Bay

During 10 August 1973 while conducting an oceanographic program in deep waters off the North Slope of Alaska, an opportunity arose to make an airborne radiation thermometer (ART) flight to map the surface water temperature of Harrison Bay .... Little is known about the oceanography of the Bay. Yet this zone may well come under considerable, if not great, environmental stresses stemming from present localization of resource development and exploitation. This paper presents a summary of the results of the low-altitude ART flight. ... A Barnes Engineering Company PRT-5, 9.5-11.5 µ Infrared Radiometer with a field of view of 2 degrees was used .... The temperature survey was carried out using 2 helicopters ... flying a grid pattern and measuring the surface temperature along the flight track. The flight was conducted at a nominal altitude of 46 metres, with a flight speed of 150 km/hr. Navigation was done by visual contact with the coast and by radar tracking from the Glacier. Clear, cloud-free conditions existed in the entire study area during the survey. Continuous winds (>3.0 m/sec) mixed the surface waters so that the radiometer measurements are representative of bulk temperature rather than the skin temperature of the water. The ART equipment was calibrated before, during, and after the flight. ... Contours of the surface-water temperature distribution of Harrison Bay are presented .... Two major features are exhibited: the lack of large river effluent plumes; and the penetration of relatively cold water from the west into Harrison Bay. The weak packing of isotherms (4° to 8°C) near the Colville River delta indicates that river runoff was very low in early August and freshwater influence was restricted to near the shore. This was expected. ... the Colville River has a total annual discharge of 16 × 10**9 m³ of which 80 per cent occurs the first twenty days of June. During the rest of the summer, river flow is very low. In the second feature ... the 3°C isotherm represented the boundary of the cold water and was accompanied by a sharp colour separation: offshore of the isotherm the water was green whereas inshore the water was brown. It is also interesting to note that the 3°C isotherm paralleled the 5.5 metre isobath in Harrison Bay. Along the North Slope coast, surface currents depend largely on local winds, are highly variable (0 to 60 cm/sec), and may even reverse direction .... The wind is generally from the east during the summer and rarely exceeds 10 m/sec. However, from 6 to 11 August 1973, the wind direction was from the west-southwest at an average of 4 m/sec. This was sufficient to cause the nearshore waters to flow easterly, pushing the colder coastal waters into Harrison Bay. Assuming steady state conditions the magnitude of the wind-driven cold-water current was 12 cm/sec. The pocket of <4°C water near Cape Halkett ... may represent an eddy. The surface water temperature distribution of Harrison Bay observed 10 August 1973 is probably unique in that the winds were blowing from the west causing the presence of a tongue of cold water to occur which covered a great part of the bay. However, the data should add to our sparse understanding of the area and point out the need for continued study

Distribution Patterns of Diatoms in Cedar Run

Author Institution: Department of Botany, The Ohio State UniversityThe diatom communities of Cedar Run, Champaign County, Ohio were studied to determine their spatial and seasonal variation. Collections were obtained using glass slides as an artificial substratum and the diatom community was determined by identifying and counting approximately 1,000 valves on each slide. There were 190 diatom taxa identified, 82 of which were new records for Ohio. A multivariate analysis of the data resulted in unique clustering of points for each station, indicating a heterogeneous diatom assemblage in Cedar Run. Results were interpreted as indicating that areal effect on diatom community patterns masked that of seasonal influence in Cedar Run. A seasonal pattern was apparent when data for each station were considered separately from other stations

An Examination of the First Sediment Cores From Mountain Lake, Giles County, Virginia, for Diatoms and Pollen

Mountain Lake, Virginia is a small, unique, oligotrophic, subalpine ecosystem in the southern Appalachians. Its geology, origin, climate, and history have influenced its morphometry, and therefore its sedimentology and algal flora. Radiocarbon dates establish specific Mountain Lake sediment ages at 1800, 4100, and 6100 years BP. Sediment core analysis suggests at least 6 prolonged periods when Mountain Lake probably was nearly dry or very small in size. These individual low-water periods (at approximately 100, 400, 900, 1200, 1800 and 4100 years BP) are evidenced by changes in diatom and pollen content, sedimentary erosion features, and the presence of wood fragments, plant fibers, and abundant Sphagnum and fern spores. The ratio of planktonic-to-benthic diatom taxa was used to estimate approximate past water depths from sediment. One or more of these low-water intervals may correspond to a drier climate coincident with solar activity minima. Resolution of prolonged low water intervals probably has been enhanced by the continuous loss of water through the crevice or fault at the lake bottom. The sediment core record suggests also that some eutrophication has occurred during the 20th century, in parallel with anthropogenic impacts (i.e. increased sedimentation, induced eutrophication, and diatom diversity changes). These findings provide the first published diatom, pollen and sedimentology-based paleolimnology for this lake

Airborne Asian Dust: Case Study of Long-Range Transport and Implications for the Detection of Volcanic Ash

The transport of fine-grained Asian dust from its source (e.g., the Gobi Desert, Mongolia) to North America is a common springtime phenomenon. Because of its chemical composition (silicon, iron, aluminum, and calcium) and its particle size distribution (mean aerodynamic diameter 2-4 mum), Asian dust produces a negative signal in the split-window T-4 - T-5 algorithm, as does airborne volcanic ash. The split-window algorithm is commonly used by operational volcanic ash advisory centers. Thus, it is important to find ways to differentiate between airborne Asian dust and airborne volcanic ash. Use of Total Ozone Mapping Spectrometer aerosol and sulfur dioxide indices, in conjunction with the split-window method, can mitigate the possibility of a false airborne volcanic ash alarm. Asian dust also is important for other reasons. Thus, meteorological agencies should monitor it because 1) it can be transported thousands of kilometers from its source region and thus is of global interest (e.g., effects on radiative forcing) and 2) fine-grain particles pose a potentially serious public health hazard

Comparing Maps of Mean Monthly Surface Temperature and Precipitation for Alaska and Adjacent Areas of Canada Produced by Two Different Methods

Maps of mean monthly surface temperature and precipitation for Alaska and adjacent areas of Canada, produced by Oregon State University’s Spatial Climate Analysis Service (SCAS) and the Alaska Geospatial Data Clearinghouse (AGDC), were analyzed. Because both sets of maps are generally available and in use by the community, there is a need to document differences between the processes and input data sets used by the two groups to produce their respective set of maps and to identify similarities and differences between the two sets of maps and possible reasons for the differences. These differences do not affect the observed large-scale patterns of seasonal and annual variability. Alaska is divided into interior and coastal zones, with consistent but different variability, separated by a transition region. The transition region has high interannual variability but low long-term mean variability. Both data sets support the four major ecosystems and ecosystem transition zone identified in our earlier work. Differences between the two sets of maps do occur, however, on the regional scale; they reflect differences in physiographic domains and in the treatment of these domains by the two groups (AGDC, SCAS). These differences also provide guidance for an improved observational network for Alaska. On the basis of validation with independent in situ data, we conclude that the data set produced by SCAS provides the best spatial coverage of Alaskan long-term mean monthly surface temperature and precipitation currently available.On a analysé des cartes représentant les moyennes mensuelles des précipitations et des températures de l’air en surface pour l’Alaska et les zones contiguës du Canada. Ces cartes avaient été établies par le service d’analyse du climat spatial (SCAS) de l’université de l’Oregon et le centre d’échange de données géospatiales de l’Alaska (AGDC). Vu qu’en général le public peut se procurer les deux ensembles de cartes et qu’il les utilise, il est nécessaire de documenter les différences entre les processus et les jeux de données d’entrée utilisés par les deux groupes pour créer leur propre ensemble de cartes, ainsi que de dégager les similarités et les différences entre les deux ensembles de cartes et les raisons possibles de ces différences. Ces dernières n’affectent pas les schémas de variabilité saisonnière et annuelle observés à grande échelle. L’Alaska est divisé en zones intérieures et zones côtières, possédant une variabilité constante mais différente, séparées par une région de transition. Celle-ci possède une grande variabilité interannuelle mais une faible variabilité à long terme de la moyenne. Les deux jeux de données sont compatibles avec les quatre grands écosystèmes et leurs zones de transition que nous avions identifiés dans nos travaux antérieurs. Il y a cependant des différences à l’échelle régionale entre les deux ensembles de cartes; elles témoignent de différences dans les domaines physiographiques et dans le traitement que font les deux groupes (AGDC et SCAS) de ces domaines. Ces différences offrent également une piste pour l’établissement d’un réseau d’observation amélioré pour l’Alaska. En nous basant sur une validation fondée sur des données indépendantes recueillies in situ, nous concluons que le jeu de données produit par SCAS représente actuellement la meilleure couverture spatiale disponible pour les moyennes mensuelles à long terme des précipitations et des températures de l’air en surface en Alaska

Hydrologic Scales, Cloud Variability, Remote Sensing, and Models: Implications for Forecasting Snowmelt and Streamflow

Accurate prediction of available water supply from snowmelt is needed if the myriad of human, environmental, agricultural, and industrial demands for water are to be satisfied, especially given legislatively imposed conditions on its allocation. Robust retrievals of hydrologic basin model variables (e.g., insolation or areal extent of snow cover) provide several advantages over the current operational use of either point measurements or parameter-izations to help to meet this requirement. Insolation can be provided at hourly time scales (or better if needed during rapid melt events associated with flooding) and at 1-km spatial resolution. These satellite-based retrievals incorporate the effects of highly variable (both in space and time) and unpredictable cloud cover on estimates of insolation. The insolation estimates are further adjusted for the effects of basin topography using a high-resolution digital elevation model prior to model input. Simulations of two Sierra Nevada rivers in the snowmelt seasons of 1998 and 1999 indicate that even the simplest improvements in modeled insolation can improve snowmelt simulations, with 10%–20 % reductions in root-mean-square errors. Direct retrieval of the areal extent of snow cover may mitigate the need to rely entirely on internal calculations of this variable, a reliance that can yield large errors that are difficult to correct until long after the season is complete and that often leads to persistent underestimates or overestimates of the volumes of the water to operational reservoirs. Agencie

STAT3 Impairs STAT5 Activation in the Development of IL-9-Secreting T Cells

Th cell subsets develop in response to multiple activating signals, including the cytokine environment. IL-9-secreting T cells develop in response to the combination of IL-4 and TGF-β, although they clearly require other cytokine signals, leading to the activation of transcription factors including STAT5. In Th17 cells, there is a molecular antagonism of STAT5 with STAT3 signaling, although whether this paradigm exists in other Th subsets is not clear. In this paper, we demonstrate that STAT3 attenuates the ability of STAT5 to promote the development of IL-9-secreting T cells. We demonstrate that production of IL-9 is increased in the absence of STAT3 and cytokines that result in a sustained activation of STAT3, including IL-6, have the greatest potency in repressing IL-9 production in a STAT3-dependent manner. Increased IL-9 production in the absence of STAT3 correlates with increased endogenous IL-2 production and STAT5 activation, and blocking IL-2 responses eliminates the difference in IL-9 production between wild-type and STAT3-deficient T cells. Moreover, transduction of developing Th9 cells with a constitutively active STAT5 eliminates the ability of IL-6 to reduce IL-9 production. Thus, STAT3 functions as a negative regulator of IL-9 production through attenuation of STAT5 activation and function

Scottish theme towns: have new identities enhanced development?

Three small towns in southwest Scotland have recently been branded as distinct theme towns, based on books, artists and food. This is an attempt to make them more attractive to visitors and thereby improve their economy. The objective of this research is to establish whether the new identities possessed by the towns have enhanced their development. It is argued, using data reviewing the past decade, that they have all developed, albeit at different rates, in terms of the economy and culture. Moreover, it is maintained that social capital has been enhanced and is a factor whose importance has been under-appreciated by planners and observers of this type of process. The relevance of the new identity to the pre-branding identity is also seen as a factor in successful development and ideas of authenticity and heritage are brought to bear on the relationship

PU.1 expression in T follicular helper cells limits CD40L-dependent germinal center B cell development.

PU.1 is an ETS family transcription factor important for the development of multiple hematopoietic cell lineages. Previous work demonstrated a critical role for PU.1 in promoting Th9 development, and in limiting Th2 cytokine production. Whether PU.1 has functions in other T helper lineages is not clear. In this report we examined the effects of ectopic expression of PU.1 in CD4+T cells and observed decreased expression of genes involved with the function of T follicular helper (Tfh) cells, including Il21 and Tnfsf5 (encoding CD40L). T cells from conditional mutant mice that lack expression of PU.1 in T cells (Sfpi1lck−/−) demonstrated increased production of CD40L and IL-21 in vitro. Following adjuvant-dependent or adjuvant-independent immunization, we observed that Sfpi1lck−/− mice had increased numbers of Tfh cells, increased germinal center B cells, and increased antibody production in vivo. This correlated with increased expression of IL-21 and CD40L in Tfh cells from Sfpi1lck−/− mice, compared to control mice. Finally, although blockade of IL-21 did not affect germinal center B cells in Sfpi1lck−/− mice, anti-CD40L treatment of immunized Sfpi1lck−/− mice decreased germinal center B cell numbers and antigen-specific immunoglobulin concentrations. Together, these data indicate an inhibitory role of PU.1 in the function of T follicular helper cells, germinal centers, and Tfh-dependent humoral immunity