Online Articles
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An Evaluation of Underwater Epoxies to Permanently Install Temperature Sensors in Mountain Streams Type: Article Author(s): Daniel J. Isaak and Dona L. Horan Subject Area: Biology, Life Sciences and Environmental Science Industry Focus: Water Related Onset Products: U-BOLT-KIT Publishing Institution: North American Journal of Fisheries Management Abstract: Stream temperature regimes are of fundamental importance in understanding the patterns and processes in aquatic ecosystems, and inexpensive digital sensors provide accurate and repeated measurements of temperature. Most temperature measurements in mountain streams are made only during summer months because of logistical constraints associated with stream access and concerns that large annual floods will destroy sensor installations. We assessed six underwater epoxies to determine whether sensors could be attached to large rocks already in streams to provide durable installations and whether temperature measurements would be biased by heat conduction through the rocks. Only one of the six test epoxies bonded the sensors firmly to rock surfaces in laboratory trials. In subsequent field trials, 9 of 11 sensors attached to rocks with this epoxy successfully weathered above-average floods in four Idaho and Nevada streams in 2010. Comparisons of daily maximum, minimum, and mean temperatures between rock-mounted sensors and control sensors at 10 rocks suggested temperature measurements were not biased by attachment to rocks. We also assessed the effect of direct sunlight on sensors by removing solar shields from some sensors and noted rapid and statistically significant increases in daily means (+0.21◦C) and maxima (+0.54◦C), but not minima (−0.01◦C).Use of underwater epoxy for permanent installation of temperature sensors in mountain streams is a viable technique if an appropriate epoxy is chosen, sensors are shielded from direct sunlight, and rocks large enough to withstand floods are used. Moreover, installations using epoxy are rapid (approximately 20 min), and firm attachments to rock surfaces over a range of stream temperatures (5–20◦C) are possible.
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Temperature Distribution and Air Pollution in Phnom Penh, Cambodia - Influence of Land Use and the Mekong and Tonle Sap Rivers Type: Article Author(s): Masami Furuuchi, Takahiro Murase, Michiko Yamashita, Hideo Oyagi, Ken-ichi Sakai, Shinji Tsukawaki, Sotham Sieng, and Mitsuhiko Hata Subject Area: Biology, Life Sciences and Environmental Science Industry Focus: Water Related Onset Products: Publishing Institution: Furuuchi et al., Aerosol and Air Quality Research, Vol. 6, No. 2, pp. 134-149, 2006 Abstract: The temperature distribution in Phnom Penh was measured using a car to evaluate the thermal characteristics and air pollution in the city. The measurements were made by using temp-hygro sensors with a data logger installed on the car roof and were conducted both during day and night to evaluate the influence of land use. The water temperature was also measured in the River Tonle Sap and the Mekong. By measuring the temperature as a function of distance from the banks of the Mekong and Tonle Sap, the cooling effect of the river was also investigated. Ambient particulates were simultaneously sampled at three different sites in the city along with NO2 and PAHs and heavy metal concentrations were analyzed. The temperature distribution was compared with the concentration of chemical compositions and NO2. The maximum temperature difference, the so called heat island intensity, was observed during the daytime and was around 4-5oC, and was less than 2oC during the nighttime. The maximum and minimum temperatures respectively were observed in the southern part of the city and the river peninsula between the Tonle Sap river and the Mekong, and a strong cooling effect of river water was found. The water temperature was consistently lower than the ambient and temperature distributions perpendicular to the river and was found to increase with the distance from the riverbank, suggesting that inland areas were cooled to some extent. Comparison of the concentrations of anthropogenic PAHs and NO2 were found to be closely related to temperature.
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Intra-annual thermal patterns in the main rivers of the Sabie Catchment, Mpumalanga, South Africa Type: Article Author(s): NA Rivers-Moore and GPW Jewitt Subject Area: Biology, Life Sciences and Environmental Science Industry Focus: Water Related Onset Products: Publishing Institution: School of Bioresources Engineering and Environmental Hydrology, University of KwaZulu-Natal, P/Bag X01, Scottsville 3209, South Africa Abstract: Water temperatures serve as indices of catchment condition, being a function of a multitude of variables acting as both drivers and buffers, at different temporal and spatial scales. Data loggers were used to record time series of hourly water temperatures within the Sabie, Sand and Marite Rivers of the Sabie catchment, Mpumalanga, South Africa. Two years of hourly water temperatures were scaled up to provide daily statistics of water temperatures, which provided information on intra-annual thermal variability as well as how this changed along the longitudinal axis of the Sabie River. In general, mean and maximum water temperatures, and thermal variability, increased with downstream distance in the Sabie River. Water temperatures in the two main tributaries of the Sabie River, viz. the Marite and Sand Rivers, displayed higher maxima and lower minima than corresponding sites in the Sabie River. Further research on the role of hyporheic water and the contribution of tributaries is proposed, together with additional long-term collection of water temperature time series.
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Temperature variation in nests of Caiman crocodilus Type: Article Author(s): Armando H. Escobedo Galván Subject Area: Biology, Life Sciences and Environmental Science Industry Focus: Water Related Onset Products: Publishing Institution: Escuela de Ciencias Biológicas, Universidad Nacional, Heredia, Costa Rica Abstract: Caiman crocodilus is a widely distributed species in the Neotropics; however, studies of incubation temperatures in wildlife are uncommon. Incubation temperatures in four nests of Caiman crocodilus were measured with a digital thermometer, in the National Wildlife Refuge Caño Negro, Costa Rica. Average temperatures in these four nests (no. 1-4) were 32.13 + 0.92 °C (no. 1), 32.46 + 0.77 °C (no. 2), 33.60 + 0.95 °C (no. 3), and 31.78 + 2.30 °C (no. 4). Temperature variations recorded showed higher temperatures than those reported from other studies in Caño Negro. The temperatures registered in this study will lead to a higher proportion of males within the caiman population, reducing the number of future reproducing females and, therefore, in the population viability.
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Photosynthetic performance of benthic microbial mats in Lake Hoare, Antarctica Type: Article Author(s): Kay Vopel and Ian Hawes Subject Area: Biology, Life Sciences and Environmental Science Industry Focus: Water Related Onset Products: Publishing Institution: American Society of Limnology and Oceanography, Inc. Abstract: We measured in situ photosynthesis of benthic microbial mats at various depths in Lake Hoare, a permanently ice-covered lake of the McMurdo Dry Valleys, Antarctica, using oxygen (O2) microelectrodes. We further investigated the vertical distribution and activity of pigments in the microbial mats using an imaging pulseamplitude-modulated fluorometer. Microbial mats to at least 16.6-m water depth are net producers of O2 during the summer period. Net O2 production ranges from 100–500 mmol m22 h21 at incident downwelling irradiances of photosynthetically active radiation (PAR) of 1.0–4.6 mmol quanta m22 s21. Photosynthesis of mat-forming cyanobacteria and diatoms occurs at all lake depths at or close to maximum efficiency. We measured absorption by the pigment arrays at a single water depth and, by assuming that absorption is water-depth invariant, we estimated an area-specific maximum community quantum yield of 0.073 mol carbon per mol photons. A community compensation irradiance of 0.1 mmol quanta m22 s21 was estimated, reflecting extreme shade acclimation. These results confirm estimates previously derived from laboratory gas-exchange measurements and imply that even minor changes in the intensity of the incident downwelling irradiance of PAR caused by, for example, changes in the transparency of the ice cover or the optical properties of the water column can significantly alter rates of benthic carbon fixation. In situ measurements were confined to mats with flat surfaces. Laboratory measurements at the surface of mats with pinnacled surfaces revealed a complex small-scale chemical structure at the mat–water interface.
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Local and regional scale effects of wave exposure, and absolute versus effective shore level on patterns of intertidal zonation Type: Article Author(s): Christopher D. G. Harley and Brian S. T. Helmuth Subject Area: Biology, Life Sciences and Environmental Science Industry Focus: Water Related Onset Products: Publishing Institution: American Society of Limnology and Oceanography, Inc. Abstract: Rocky intertidal ecosystems are characterized by marked zonation patterns in which species replace one another along the vertical gradient of emersion time. Yet, we still do not fully understand the reasons that zonation patterns are variable in space and time. Here, we use effective shore level (ESL), a metric that incorporates the modifying influence of wave splash, to describe the relationship between uninterrupted emersion time and the zonation patterns of two ecologically important species: the mussel Mytilus californianus and the barnacle Balanus glandula. At the local scale (10s to 100s of meters) on Tatoosh Island, the upper limits of both species are closely related to ESL, regardless of substrate aspect or maximum temperature. At larger spatial scales (10s to 100s of kilometers), the upper limit of Balanus is related to ESL at cool sites but not at hotter sites. Thus, although ESL explains most of the local-scale variation in zonation at a cool site, other factors (temperature, desiccation) likely become important as spatial scale increases to incorporate warmer sites. Our results emphasize that an understanding of where and when specific ecological factors are limiting is crucial for our ability to explain and predict large-scale biological patterns in space and time.
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Measuring Stream Temperature with Digital Data Loggers: A User’s Guide Type: Article Author(s): Jason Dunham, Gwynne Chandler, Bruce Rieman, Don Martin Subject Area: Biology, Life Sciences and Environmental Science Industry Focus: Water Related Onset Products: Publishing Institution: United States Department of Agriculture Abstract: Digital data loggers (thermographs) are among the most widespread instruments in use for monitoring physical conditions in aquatic ecosystems. The intent of this protocol is to provide guidelines for selecting and programming data loggers, sampling water temperatures in the field, data screening and analysis, and data archiving.
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The timing of benthic copepod emergence Type: Article Author(s): Michael Teasdale, Kay Vopel, David Thistle Subject Area: Biology, Life Sciences and Environmental Science Industry Focus: Water Related Onset Products: Publishing Institution: The American Society of Limnology and Oceanography, Inc. Abstract: We investigated emergence of marine benthic harpacticoid and cyclopoid copepods from subtidal sediment into the bottom water. Previous studies that used traps in the field found that copepods emerged from the sediment within 2 h of dusk. We examined emergence in 20-min sampling periods over 13 h from 1200 to 0100 h in a laboratory flume under conditions of constant flow speed. The light intensity was adjusted to field conditions every 20 min. We observed a peak in emergence during the 20-min sampling period after the onset of darkness, greatly increasing the accuracy with which the timing of emergence is known. This result will help to set the stage for studies of emergence cues.
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Spawning movements of European grayling Thymallus thymallus in the River Aisne (Belgium) Type: Article Author(s): Michaël OVIDIO, Denis PARKINSON, Damien SONNY and Jean-Claude PHILIPPART Subject Area: Biology, Life Sciences and Environmental Science Industry Focus: Water Related Onset Products: Publishing Institution: University of Liège, Life Sciences Department, Laboratory of Fish Demography and Hydroecology Abstract: In three consecutive years (1998 to 2000), 20 adult grayling Thymallus thymallus (L.) (FL ± SD: 326 ± 43 mm) were radio-tracked during circum reproduction period (February to May) in the River Aisne, Belgium. Before the spawning period, grayling remained consistently in the pool-riffle sequence in which they had been captured. Pre-spawning migration time extended from 7 to 29 March. Distances travelled during the spawning migration ranged from 70 to 4980 m (mean ± S.E.: 1234 ± 328 m). Spawning migrations started under conditions of decreasing water level and increasing water temperature in a thermal range (daily mean T°) from 5 to 8 °C. Spawners remained from 1 to 31 days (mean ± S.D.: 10.4 ± 9.8 days) at the spawning grounds and performed a post-spawning homing from 28 March to 18 April in decreasing water flow and in a thermal range (daily mean T°) from 7 to 11 °C. This study demonstrates that migration patterns of grayling are similar between years, but with a timing adjusted as a response to annual variations of the hydroclimatic conditions.
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Characterization of E. coli levels at 63rd Street Beach Type: Article Author(s): R. L. Whitman, T.G. Horvath, M.L. Goodrich and M.B. Nevers, U.S. Geological Survey Lake Michigan Ecological Research Station Subject Area: Biology, Life Sciences and Environmental Science Industry Focus: Water Related Onset Products: Publishing Institution: City of Chicago Abstract: The City of Chicago, the United States Geological Survey (USGS), and the Chicago Park District developed a cooperative relationship in early 2000 to provide information on the nearshore waters of the Chicago area. In particular, the City wanted a more thorough understanding of excessive E. coli occurrences at 63rd Street Beach, near Jackson Park. Chicago historically complies with monitoring rules on a voluntary basis in the interest of public heath and recreational enjoyment. In fact, Chicago has one of the most intensive monitoring programs in the Great Lakes region. Chicago’s hope was that with a thorough understanding of the nature and source of E. coli problems, they could begin to address remediation. Further, Chicago desired information on factors that related to these exceedances for purposes of developing real-time prediction models that could eventually augment or even replace traditional monitoring approaches. USGS, in turn, desired the opportunity to gather intensive information on the spatial-temporal distributions and population characteristics of E. coli in order to understand how environmental conditions, sources, and bacteria concentrations interact. This, in turn, would help USGS provide information for better management of public swimming areas in the Great Lakes area.
