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1

Marine geology of the St. Lawrence Estuary  

NASA Astrophysics Data System (ADS)

The St. Lawrence Estuary, Eastern Canada, contains a very thick (>450 m) Quaternary sedimentary sequence. The results from recently conducted geophysical surveys in conjunction with piston coring indicate that these sediments were deposited under very high sedimentation rates, sometimes as high as ~30 m/ka during the last deglaciation. Results also reveal evidence of large submarine landslides during the Holocene, changes in sedimentation rates and the significant role of submarine canyons and channels to transfer sediments from the coast to the deeper marine environment. Finally, this paper highlights the presence of more than 1900 pockmarks on the seafloor of the St. Lawrence Estuary and discusses their possible origins: active hydrocarbon seeps in the Laurentian Channel and biogenic gas seepage on the northwestern shoulder of the Laurentian Channel.

St-Onge, Guillaume; Duchesne, Mathieu J.; Lajeunesse, Patrick

2011-05-01

2

Cancer in beluga from the St. Lawrence estuary.  

PubMed Central

Martineau et al. (2002) reported that St. Lawrence beluga (SLB) have high cancer rates. Unfortunately, errors in their interpretation of the data have led them to overstate the importance of cancer and its links to environmental sources.

Hammill, Mike O; Lesage, Veronique; Kingsley, Michael C S

2003-01-01

3

Oceanography and Quaternary geology of the St. Lawrence Estuary and the Saguenay Fjord  

NASA Astrophysics Data System (ADS)

The St. Lawrence Estuary is an environment marked by important freshwater discharge and well stratified water masses, recording large seasonal contrast in surface waters from freezing conditions in winter to temperate conditions in summer due to a very strong seasonal cycle in overlying air temperature. High productivity takes place in the pelagic and benthic environments, where a recent trend toward bottom water hypoxia is observed. The area was profoundly marked by the Quaternary glaciations. Thick glaciomarine sequences dating from the last deglaciation are observed in the Estuary and along the shores, whereas a relatively thin layer (a few meters at most) of hemipelagic mud was deposited during the Holocene.

de Vernal, Anne; St-Onge, Guillaume; Gilbert, Denis

2011-05-01

4

Hypoxia in the bottom water of the St. Lawrence Estuary: Is this ecosystem on borrowed time?  

NASA Astrophysics Data System (ADS)

When the rate of oxygen consumption in water exceeds the rate of supply, the oxygen concentration decreases and may reach levels that threaten the survival of many aquatic organisms. Waters with such low oxygen levels are termed severely hypoxic ([O2] < 62.5 µmol L-1). In 2011, the World Resources Institute identified 479 hypoxic coastal zones around the world, including fjords, estuaries, bays, shelves, as well as enclosed and semi-enclosed seas. These hypoxic environments are mainly found in coastal areas as a result of industrial and agricultural fertilizer discharge (i.e. eutrophication), and they develop during summer when the water column is strongly stratified; but hypoxia may also occur naturally and persist year-round. Historical records reveal that the dissolved oxygen concentration has progressively decreased in the bottom water of the Lower St. Lawrence Estuary (LSLE) during the last century and reached the severe hypoxic threshold in the 1980s where it has hovered ever since. The development of severe hypoxia in the LSLE has been mostly attributed to a gradual change in the properties (e.g. higher temperature, lower dissolved oxygen concentration) of the bottom water that enters the Laurentian Channel (Gulf of St. Lawrence, Eastern Canada). In addition, evidence of eutrophication has been reported in the LSLE, possibly increasing the oxygen demand in the water column and sediment. Increased respiration rates in the bottom water, in response to warming (from 3.3 to 5°C), has also been proposed to explain the increased depletion of oxygen in the Gulf. Nevertheless, whether hypoxia in the bottom water of the Laurentian Channel results from anthropogenic or natural forcings or both remain unclear. This presentation will examine the processes that govern the spatial distribution of dissolved oxygen in the water column and identify the causes that led to the development of large-scale hypoxia in the bottom waters of the LSLE. A laterally integrated advection-diffusion two-dimensional model was implemented to simulate the spatial distribution of dissolved oxygen and the development of hypoxic conditions in the deep waters of the Laurentian Channel (Estuary and Gulf of St. Lawrence). Our simulations reveal that the horizontal distribution of dissolved oxygen in the bottom waters of the Laurentian Channel is determined by a combination of physical and biogeochemical processes, whereas its vertical distribution is governed by the deep water circulation. This result strongly suggests that the physics of the system and the source water properties are mostly responsible for the oxygen depletion and its distribution pattern in the deep water column.

Lefort, S.; Gratton, Y.; Mucci, A.; Dadou, I.; Gilbert, D.

2012-04-01

5

Light absorption and fluorescence properties of chromophoric dissolved organic matter (CDOM), in the St. Lawrence Estuary (Case 2 waters)  

Microsoft Academic Search

The absorption coefficient and the fluorescence emission of chromophoric (coloured) dissolved organic matter (CDOM) were determined along a 1200 km transect in the Estuary and Gulf of St. Lawrence. Fluorescence spectra were spectrally corrected against a reference standard and normalized to the water Raman signal to provide results in Raman units. Because CDOM originates mainly from freshwater river runoff in

B. Nieke; R. Reuter; R. Heuermann; H. Wang; M. Babin; J. C. Therriault

1997-01-01

6

Toxoplasmosis in Beluga Whales ( Delphinapterus leucas ) from the St Lawrence Estuary: Two Case Reportsand a Serological Survey  

Microsoft Academic Search

Toxoplasmosis was diagnosed in two free-ranging beluga whales from the St Lawrence estuary, Quebec, Canada, in 1988 and 1998. Histologically, tachyzoites and bradyzoites were present in the brain, spleen, lymph nodes, adrenals and lungs of both animals, and in the thymus of one. These organisms were readily labelled by an indirect immunohistochemical method for Toxoplasma gondii antigens. In the lymph

I Mikaelian; J Boisclair; JP Dubey; S Kennedy; D Martineau

2000-01-01

7

Conceptualization and implementation of a multi-agent model to simulate whale-watching tours in the St. Lawrence Estuary in Quebec, Canada  

Microsoft Academic Search

The Saguenay St. Lawrence Marine Park (SSLMP) and the adjacent Marine Protected Area (MPA) in the St. Lawrence Estuary, in Quebec, cover a territory of exceptional biodiversity including 12 species of marine mammals, nearly half of which are considered to be endangered species. Whale-watching trips and other human activities related to commercial shipping, tourism, and recreation generate very intensive traffic

Sk. Morshed Anwar; Cédric A. Jeanneret; Lael Parrott; Danielle J. Marceau

2007-01-01

8

Recent eutrophication and consequent hypoxia in the bottom waters of the Lower St. Lawrence Estuary: Micropaleontological and geochemical evidence  

Microsoft Academic Search

Micropaleontological and geochemical analyses were carried out on two sediment box cores (AH00-2220 and CR02-23) recovered in the Lower St. Lawrence Estuary (LSLE) in order to document recent temporal variations of primary productivity and carbon fluxes to the bottom waters. These reveal a ten-fold increase in the accumulation rate of dinoflagellate cysts and benthic foraminifera in the sediment over the

Benoît Thibodeau; Anne de Vernal; Alfonso Mucci

2006-01-01

9

Benthic fluxes of dissolved organic nitrogen in the Lower St. Lawrence Estuary and implications for selective organic matter degradation  

NASA Astrophysics Data System (ADS)

The distribution of dissolved organic nitrogen (DON) and carbon (DOC) in sediment pore waters was determined at nine locations along the St. Lawrence Estuary and in the Gulf of St. Lawrence. The study area is characterized by gradients in the sedimentary particulate organic matter (POM) reactivity, bottom water oxygen concentrations, as well as benthic respiration rates. Based on pore water profiles we estimated the benthic diffusive fluxes of DON and DOC. Our results show that DON fluxed out of the sediments at significant rates (110 to 430 ?mol m-2 d-1). DON fluxes were positively correlated with sedimentary POM reactivity and sediment oxygen exposure time (OET), suggesting direct links between POM quality, aerobic remineralization and the release of DON to the water column. DON fluxes were on the order of 30% to 64% of the total benthic inorganic fixed N loss due to denitrification, and often exceeded the diffusive nitrate fluxes into the sediments. Hence they represented a large fraction of the total benthic N exchange. This result is particularly important in light of the fact that DON fluxes are usually not accounted for in estuarine and coastal zone nutrient budgets. The ratio of the DON to nitrate flux increased from 0.6 in the Lower Estuary to 1.5 in the Gulf. In contrast to DON, DOC fluxes did not show any significant spatial variation along the Laurentian Channel (LC) between the Estuary and the Gulf (2100 ± 100?mol m-2 d-1), suggesting that production and consumption of labile DOC components proceed at similar rates, irrespective of the overall benthic characteristics and the reactivity of POM. As a consequence, the molar C/N ratio of dissolved organic matter (DOM) in pore water and the overlying bottom water varied significantly along the transect, with lowest C/N in the Lower Estuary (5-6) and highest C/N (> 10) in the Gulf. We observed large differences between the C/N of pore water DOM with respect to POM, and the degree of the C- versus -N element partitioning seems to be linked to POM reactivity and/or redox conditions in the sediment pore waters. Our results thus highlight the variable effects selective OM degradation and preservation can have on bulk sedimentary C/N ratios, decoupling the primary source C/N signatures from those in sedimentary archives. Our study further underscores that the role of estuarine sediments as efficient sinks of bioavailable nitrogen is strongly influenced by the release of DON during early diagenetic reactions, and that DON fluxes from continental margin sediments represent an important internal source of N to the ocean.

Alkhatib, M.; del Giorgio, P. A.; Gelinas, Y.; Lehmann, M. F.

2013-05-01

10

Benthic fluxes of dissolved organic nitrogen in the lower St. Lawrence estuary and implications for selective organic matter degradation  

NASA Astrophysics Data System (ADS)

The distribution of dissolved organic nitrogen (DON) and carbon (DOC) in sediment porewaters was determined at nine locations along the St. Lawrence estuary and in the gulf of St. Lawrence. In a previous manuscript (Alkhatib et al., 2012a), we have shown that this study area is characterized by gradients in the sedimentary particulate organic matter (POM) reactivity, bottom water oxygen concentrations, and benthic respiration rates. Based on the porewater profiles, we estimated the benthic diffusive fluxes of DON and DOC in the same area. Our results show that DON fluxed out of the sediments at significant rates (110 to 430 ?mol m-2 d-1). DON fluxes were positively correlated with sedimentary POM reactivity and varied inversely with sediment oxygen exposure time (OET), suggesting direct links between POM quality, aerobic remineralization and the release of DON to the water column. DON fluxes were on the order of 30 to 64% of the total benthic inorganic fixed N loss due to denitrification, and often exceeded the diffusive nitrate fluxes into the sediments. Hence they represented a large fraction of the total benthic N exchange, a result that is particularly important in light of the fact that DON fluxes are usually not accounted for in estuarine and coastal zone nutrient budgets. In contrast to DON, DOC fluxes out of the sediments did not show any significant spatial variation along the Laurentian Channel (LC) between the estuary and the gulf (2100 ± 100 ?mol m-2 d-1). The molar C / N ratio of dissolved organic matter (DOM) in porewater and the overlying bottom water varied significantly along the transect, with lowest C / N in the lower estuary (5-6) and highest C / N (> 10) in the gulf. Large differences between the C / N ratios of porewater DOM and POM are mainly attributed to a combination of selective POM hydrolysis and elemental fractionation during subsequent DOM mineralization, but selective adsorption of DOM to mineral phases could not be excluded as a potential C / N fractionating process. The extent of this C- versus N- element partitioning seems to be linked to POM reactivity and redox conditions in the sediment porewaters. Our results thus highlight the variable effects selective organic matter (OM) preservation can have on bulk sedimentary C / N ratios, decoupling the primary source C / N signatures from those in sedimentary paleoenvironmental archives. Our study further underscores that the role of estuarine sediments as efficient sinks of bioavailable nitrogen is strongly influenced by the release of DON during early diagenetic reactions, and that DON fluxes from continental margin sediments represent an important internal source of N to the ocean.

Alkhatib, M.; del Giorgio, P. A.; Gelinas, Y.; Lehmann, M. F.

2013-11-01

11

Photoinduced oxidation of Hg0(aq) in the waters from the St. Lawrence estuary.  

PubMed

The oxidation of volatile aqueous Hg0 in aquatic systems may be important in decreasing the fluxes of Hg out of the water column. Using incubations of natural samples from the St. Lawrence River, we examined some of the parameters that control this oxidation. Hg0 was found to be chiefly mediated by UV radiation since (i) "dark" oxidation was not found to be statistically significant; (ii) visible light induced a significant but slow photooxidation (k = 0.09 h(-1)); and (iii) visible + UV radiation led to a faster photooxidation (k = 0.6-0.7 h(-1)), mainly because of UV-A induced reactions. Doubling UV irradiation did not increase the reaction rate of Hg0 photooxidation in natural water samples, indicating that some factor other than photon flux was rate limiting and suggesting that the reaction involves intermediate photoproduced oxidant(s). The addition of methanol, a *OH scavenger, decreased Hg photooxidation rates by 25% in brackish waters and by 19% in artificial saline water containing semiquinones, indicating that *OH may be partly responsible for Hg0 oxidation. Photooxidation rates were not affected by oxygen concentrations and did not decrease when samples were heat-sterilized, treated with chloroform, or filtered prior to exposure to light. PMID:14750727

Lalonde, Janick D; Amyot, Marc; Orvoine, Jord; Morel, François M M; Auclair, Jean-Christian; Ariya, Parisa A

2004-01-15

12

Chemical risks associated with consumption of shellfish harvested on the north shore of the St. Lawrence River's lower estuary.  

PubMed Central

Shellfish have the capacity to accumulate chemical contaminants found in their biotope and therefore present a potential risk for consumers. This study was conducted to assess the chemical risks associated with consumption of shellfish harvested on the north shore of the St. Lawrence River's lower estuary. A survey was carried out on 162 recreational harvesters, and shellfish were sampled for chemical contaminant analysis. We quantified 10 metals, 22 polycyclic aromatic hydrocarbons (PAHs), 14 polychlorinated biphenyls (PCBs), and 10 chlorinated pesticides. We subsequently evaluated cancer and noncancer risks for four consumption scenarios based on our survey results and published results. Soft-shell clams (Mya arenaria) were by far the most consumed shellfish species. Of the 56 selected contaminants, 36 were detected in the 23 homogenates of soft-shell clam meat. None of the contaminants found in the soft-shell clams were associated with intakes that exceed the main exposure limit recommendations proposed to prevent noncancer effects. However, several limits must be considered before drawing conclusions about the relative safety of shellfish consumption regarding this end point. Furthermore, inorganic arsenic and PCBs were present in sufficient concentrations to lead to cancer risks exceeding the level often considered acceptable for environmental exposure (1 x 10 (-4) to 1 x 10(-6)) in each of the four scenarios, even for the lowest observed scenario of 15 meals of soft-shell clams per year.

Gagnon, Fabien; Tremblay, Thierry; Rouette, Justine; Cartier, Jacques-Francois

2004-01-01

13

Chemical risks associated with consumption of shellfish harvested on the north shore of the St. Lawrence River's lower estuary.  

PubMed

Shellfish have the capacity to accumulate chemical contaminants found in their biotope and therefore present a potential risk for consumers. This study was conducted to assess the chemical risks associated with consumption of shellfish harvested on the north shore of the St. Lawrence River's lower estuary. A survey was carried out on 162 recreational harvesters, and shellfish were sampled for chemical contaminant analysis. We quantified 10 metals, 22 polycyclic aromatic hydrocarbons (PAHs), 14 polychlorinated biphenyls (PCBs), and 10 chlorinated pesticides. We subsequently evaluated cancer and noncancer risks for four consumption scenarios based on our survey results and published results. Soft-shell clams (Mya arenaria) were by far the most consumed shellfish species. Of the 56 selected contaminants, 36 were detected in the 23 homogenates of soft-shell clam meat. None of the contaminants found in the soft-shell clams were associated with intakes that exceed the main exposure limit recommendations proposed to prevent noncancer effects. However, several limits must be considered before drawing conclusions about the relative safety of shellfish consumption regarding this end point. Furthermore, inorganic arsenic and PCBs were present in sufficient concentrations to lead to cancer risks exceeding the level often considered acceptable for environmental exposure (1 x 10 (-4) to 1 x 10(-6)) in each of the four scenarios, even for the lowest observed scenario of 15 meals of soft-shell clams per year. PMID:15175177

Gagnon, Fabien; Tremblay, Thierry; Rouette, Justine; Cartier, Jacques-François

2004-06-01

14

A twenty-one year temporal trend of persistent organic pollutants in St. Lawrence Estuary beluga, Canada.  

PubMed

Persistent organic pollutants (POPs) were measured in blubber from 144 stranded adult belugas (Delphinapterus leucas) found on the shores of the St. Lawrence Estuary (SLE) between 1987 and 2007. Temporal trends of POP concentrations (ln transformed) in beluga were described by three models, zero slope (ZS), linear (L) and two-segment piecewise (PW). Often two but sometimes all three models were equivalent in describing temporal trends based on Akaike's Information Criterion for small sample sizes. Over this 21-year time period, concentrations of most legacy POPs, including PCBs, DDTs and HCHs, exhibited relatively weak (?11% per year) but significant decreasing trends in beluga. For PBDEs, temporal trends were best described by a PW model, characterizing a rapid increase until 1997-1998 followed by a slower increase for males and a steady-state for females. Potential cofactors such as blubber lipid content and carcass state of preservation did not show any significant temporal trends over the time period considered. Nitrogen stable isotope ratios (?(15)N) in beluga liver, a proxy of trophic level, could not be associated to any effect on temporal trends of POP concentrations in beluga. Several POPs exhibited significant relationships with age of beluga and data were age-adjusted. Temporal trends of POP concentrations adjusted for age of beluga were reassessed but results were essentially identical as those obtained with the original POP data. Overall, POP temporal trends observed in SLE beluga are consistent with changes expected from regulations and restrictions in the use of these compounds in developed countries. PMID:24742546

Lebeuf, Michel; Measures, Lena; Noël, Michelle; Raach, Meriem; Trottier, Steve

2014-07-01

15

Modern diatom assemblages in surface sediments from the Maritime Estuary and the Gulf of St. Lawrence, Québec (Canada)  

Microsoft Academic Search

The Gulf of St. Lawrence located in the northeastern part of North America is a transitional environment from estuarine to marine conditions. Diatom analysis of 41 surface sediments samples showed great diversity with the identification of 51 genera and 135 species. Diatom concentrations in surface sediments varied between 9×103 and 1.9×106 valves per gram of dry sediment, and mean diatom

M Lapointe

2000-01-01

16

First record of the green microalgae Coccomyxa sp. in blue mussel Mytilus edulis (L.) from the Lower St. Lawrence Estuary (Québec, Canada).  

PubMed

During autumn 2012 and spring 2013, blue mussels Mytilus edulis (L.) with strongly deformed (L-shaped) posterior shell margins and green spots in soft tissue (microalgae) were collected from intertidal zone along the south shore of the Lower St. Lawrence Estuary near Rimouski (Québec, Canada). Identification of algal cells infesting mussels as Coccomyxa sp. was confirmed by rRNA sequencing and HPLC pigment analysis. Flow cytometric analysis revealed the presence of algal cells in the hemolymph and extrapallial fluid in mussels with deformed and non-deformed shells; concentrations of algal cells were ranged from about 200mL(-1) in mussels with actually non-deformed shells to concentrations reaching up to 3.8×10(7)mL(-1) in mussels with heavily deformed ones. Chemical analyses of soft tissues led us to conclude that butyltin compounds and trace metals cannot be considered among factors responsible for the shell deformity observed. Using scanning electron microscopy, the biogenic nature of the erosion on the external shell surface and aragonitic lenses of prisms in the curvature zone of deformed shells (in sections) were recorded. The sequence of the green algae from M. edulis of the Lower St. Lawrence Estuary was closely related to Coccomyxa sp. infecting M. edulis from the Flensburg Fjord (North Sea) and Modiolus modiolus (L.) from the Vityaz Bay (Sea of Japan). PMID:24837974

Zuykov, Michael; Belzile, Claude; Lemaire, Nicolas; Gosselin, Michel; Dufresne, France; Pelletier, Emilien

2014-07-01

17

Ultrahigh-Resolution Holocene Geomagnetic Paleosecular and Relative Paleointensity Record From the St. Lawrence Estuary, Eastern Canada  

NASA Astrophysics Data System (ADS)

Sedimentation rates exceeding 0.5 cm/yr are recorded in the St. Lawrence Estuary allowing very high-resolution time series to be set from long core studies. Here, we present u-channel paleomagnetic data from two cores collected during the 1999, IMAGES-V (International Marine Past Global Change Study) cruise (MD99-2220: 48° 38.32'N/68° 37.93'W, water depth: 320 m, length: 51.6 m; MD99-2221: 48° 10.60'N/68° 30.35'W, water depth: 212 m, length: 31.0 m). In both cores, a post-glacial unit composed of muds (MD99-2220) or muddy sands (MD99-2221) overlies laminated glacio-marine clays dating from the deglaciation (> 8500 cal yr BP). Eighteen AMS 14C ages provide a timeframe for the depositional sequence. The natural remanent magnetization (NRM) of the cored sediments was studied by progressive alternating field demagnetisation. Orthogonal projections of the NRM, constructed at 1 cm spacing, indicate that for most intervals these sediments are characterized by a strong, stable, single component magnetization. Aside from certain intervals in the upper post-glacial unit of MD99-2221 ( ~1.5-5 m), the inclinations of the post-glacial sediments vary about the expected inclination for the latitude of the site, with MAD values generally lower than 2° and 6° for cores MD99-2220 and -2221, respectively. Shallow inclinations or higher MAD values are observed in the underlying laminated glacio-marine clays of both cores. High frequency sedimentological variability along with sedimentation rates that exceeded 3 cm/yr may account for the poorly recorded NRM in this unit. In the overlying post-glacial muds of MD99-2220, u-channel and hysteresis data suggest that pseudo-single-domain magnetite is the dominant magnetic remanence carrier. The carrier in the post-glacial unit of MD99-2221 is dominantly coarse-grained multi-domain magnetite. Initial results indicate that the post-glacial mud unit of core MD99-2220 passes the criteria for paleointensity studies, therefore, normalized remanence records are likely to reflect changes in the intensity of the geomagnetic field. The inclination and declination records from the post-glacial units of both cores show similarities with Holocene lacustrine records from North America, suggesting that secular variation could serve as a stratigraphic tool in this region. However, when each core is placed in its own independent AMS 14C chronology, small temporal offsets within the declination and inclination patterns are observed. As the cores are less than 100 km apart and assuming that the magnetic directions are accurately recorded, these offsets reflect either dating anomalies or variable lock-in depths. Normalized remanence records of the post-glacial unit in core MD99-2220 reveal features with a wavelength in the order of 1000 years that compare with those recorded in the Lake Pepin (Minnesota, USA) sediments, suggesting that paleointensity may be recorded in these sediments. Higher frequency variations are also observed. Whether they are due to uncorrected environmental variability or geomagnetic intensity changes is presently unknown.

St-Onge, G.; Stoner, J.; Hillaire-Marcel, C.; Piper, D. J.

2001-12-01

18

PCBs and OCPs in sediment cores from the Lower St. Lawrence Estuary, Canada: evidence of fluvial inputs and time lag in delivery to coring sites.  

PubMed

Three sediment cores were collected along the longitudinal axis of the Laurentian Trough in the Lower St. Lawrence Estuary (LSLE) and an additional one at the junction of the Estuary and the Gulf of St. Lawrence. After core-slicing, each sediment layer was analyzed for polychlorinated biphenyls (PCBs) and some organochlorine pesticides (OCPs) including p,p'-dichlorodiphenyltrichloroethane (DDT) and its metabolites, hexachlorobenzene (HCB) and Mirex. 210Pb activity was also measured in these sediments, which allowed us to confirm that these cores were too much affected by the overall impact of surface mixing to be dated. Nevertheless, POP sedimentary profiles in cores from the LSLE upstream stations showed well-defined subsurface peak concentrations. Apparently, the peak inputs of POPs to these sediment cores had occurred after the years of maximum sales and production of these chemicals in North America, suggesting a time lag in the delivery of POPs to the LSLE sediments. Concentrations of POPs in the LSLE surface sediments as well as POP inventories in sediment cores decreased in the seaward direction, confirming that the head of the LSLE acts as a sink for sediments and associated constituents. Surface concentrations of sigmaPCBs, sigmaDDTs, and HCB in the most upstream core were on average similar to those reported in two fluvial lakes of the St. Lawrence River but were between 12 and 39 times lower than those from Lake Ontario. For Mirex, the surface concentration in that core was 5 and 130 times lower than the average values found in the fluvial lakes and Lake Ontario, respectively. Differences between Lake Ontario sediment cores and the most upstream core from the LSLE were much smaller on the basis of POP inventories than surface concentrations of POPs, but were still important. The total burdens of POPs in LSLE sediments below the 200 m isobath were 8704 kg for sigmaPCBs, 1825 kg for sigmaDDTs, 319 kg for HCB, and 27.5 kg for Mirex. These values represent between 1% and 10% of the total burdens of these POPs in Lake Ontario sediments. The estimated contribution of POPs by direct atmospheric deposition into the water column area of the LSLE represented at most 30% of the total sediment burdens of POPs in the LSLE, illustrating the importance of fluvial inputs. PMID:15819199

Lebeuf, Michel; Nunes, Teresa

2005-03-15

19

Concentrations and chromatographic profile of DDT metabolites and polychlorobiphenyl (PCB) residues in stranded beluga whales ( Delphinapterus leucas ) from the St. Lawrence Estuary, Canada  

Microsoft Academic Search

The concentrations and high resolution gas Chromatographic profiles of DDT metabolites and polychlorobiphenyl (PCB) congeners were determined in blubber, liver, kidney and lung tissue and milk samples of stranded beluga whales (Delphinapterus leucas) collected at localities along the coasts of the Saint Lawrence Estuary, Canada from November 1983 through December 1984. The analyses indicate that the major PCB components of

Robert Massé; Daniel Martineau; Lyne Tremblay; Pierre Béland

1986-01-01

20

Reproductive System Impairment of Mice Fed Diets Containing Beluga Whale Blubber from the St. Lawrence Estuary and Arctic Populations  

Microsoft Academic Search

The toxic potential of naturally relevant mixtures of PCBs and other organohalogens on the reproductive system of C57Bl\\/6 female mice was assessed. Mice were fed diets in which lipids were replaced by blubber of beluga whales from a highly contaminated population of the Saint Lawrence River, and a less contaminated population from the Arctic Ocean. Ratios of blubber from both

Sylvia Ruby; Luz Tavera Mendoza; Michel Fournier; Pauline Brousseau; V. Dégas

2003-01-01

21

Immunosuppression in mice fed on diets containing beluga whale blubber from the St Lawrence Estuary and the Arctic populations  

Microsoft Academic Search

In order to assess the immunotoxic potential of naturally relevant mixtures of PCBs and other organohalogens, C57Bl\\/6 mice were fed on diets in which lipids were replaced by blubber of beluga whales from the highly contaminated population of the Saint-Lawrence River, and the less contaminated population from the Arctic. Different ratios of blubber from both sources were mixed in order

M Fournier; V Dégas; T Colborn; F. O Omara; F Denizeau; E. F Potworowski; P Brousseau

2000-01-01

22

Mid and late Holocene dust deposition in eastern Canada - a preliminary multi-proxy record from the Baie bog (St. Lawrence Estuary, Quebec)  

NASA Astrophysics Data System (ADS)

Atmospheric mineral dust plays an important role in the Earth's climate through parameters such as atmospheric radiation, cloud properties and biogeochemical cycles. However, the high spatial and temporal variability of mineral dust and a lack of terrestrial archives in certain regions limit our understanding global dust-climate interactions. Ombrotrophic peatlands (bogs; atmospherically-fed only) are increasingly recognized as archives of atmospheric dust deposition. Their global distribution and high accumulation rates (i.e. high resolution) over the Holocene make them suitable substitute to marine and/or ice records. The Baie bog, located along the St. Lawrence Estuary (North Shore region, Quebec, Canada), was sampled to investigate dust deposition/palaeowinds in north eastern North America over the mid and late Holocene. The core was subsampled for elemental and isotopic geochemistry as well as particle size analyses, 210Pb and radiocarbon dating. Radiocarbon dating of the base of the peat sequence yielded an age of about 4300 yr cal BP. Initial results show periods of increased dust flux, calculated from REE concentrations, between 1000-1500 yr cal BP and 100-500 yr cal BP in the peat profile from 0.5 to 4 g m-2 yr-1. Higher dust fluxes usually occur in combination with greater particle size suggesting either stronger winds or a change of source. Periods of increased dust fluxes in the profile also correspond with changes in the macrofossil assemblages. A first attempt at source tracing through preliminary radiogenic isotopes analyses (Pb, Nd; ongoing) will also be discussed.

Pratte, Steve; Garneau, Michelle; De Vleeschouwer, François

2014-05-01

23

Humic acids from particulate organic matter in the Saguenay Fjord and the St. Lawrence Estuary investigated by advanced solid-state NMR  

NASA Astrophysics Data System (ADS)

Detailed structural information on two humic acids extracted from two sinking particulate matter samples at a water depth of 20 m in the Saguenay Fjord (F-20-HA) and the St. Lawrence Estuary (E-20-HA) (Canada), was obtained by advanced solid-state NMR. Spectral-editing analyses provided numerous structural details rarely reported in geochemical studies. The NMR data account almost quantitatively for the elemental compositions. The two humic acids were found to be quite similar, consisting of four main structural components: peptides (ca. 39 ± 3% vs. 34 ± 3% of all C for E-20-HA and F-20-HA, respectively); aliphatic chains, 14-20 carbons long (ca. 25 ± 5% vs. 17 ± 5% of all C); aromatic structures (ca. 17 ± 2% vs. 26 ± 2% of all C); and sugar rings (14 ± 2% vs. 15 ± 2% of all C). Peptides were identified by 13C{ 14N} SPIDER NMR, which selects signals of carbons bonded to nitrogen, and by dipolar DEPT, which selects CH-group signals, in particular the NCH band of peptides. The SPIDER spectra also indicate that heterocycles constitute a significant fraction of the aromatic structures. The aliphatic (CH 2) n chains, which are highly mobile, contain at least one double bond per two chains and end in methyl groups. 1H spin diffusion NMR experiments showed that these mobile aliphatic chains are in close (<10 nm) proximity to the other structural components. A major bacterial contribution to these two samples could explain why the samples, which have different dominant organic matter sources (terrestrial vs. marine), are similar to each other as well as to degraded algae and particles from other waters. The NMR data suggest structures containing mobile lipids in close proximity to peptides and carbohydrates (e.g., peptidoglycan) as found in bacterial cell walls. Measured yields of muramic acid and D-amino acids confirmed the presence of bacterial cell wall components in the studied samples.

Mao, J.-D.; Tremblay, L.; Gagné, J.-P.; Kohl, S.; Rice, J.; Schmidt-Rohr, K.

2007-11-01

24

Reproductive system impairment of mice fed diets containing beluga whale blubber from the St Lawrence estuary and arctic populations.  

PubMed

The toxic potential of naturally relevant mixtures of PCBs and other organohalogens on the reproductive system of C57Bl/6 female mice was assessed. Mice were fed diets in which lipids were replaced by blubber of beluga whales from a highly contaminated population of the Saint Lawrence River, and a less contaminated population from the Arctic Ocean. Ratios of blubber from both sources were mixed in order to perform a dose-response study. Control mice were fed diets for 90 d in which fat was replaced by corn oil or beef tallow. There were no significant effects of diets on body, liver, spleen or thymus weights. Similarly ovulation occurred in all control and experimental groups. However, Graafian follicles from ovaries of mice fed contaminated diets showed abnormal development of oocytes. Cumulus granulosa cells bind normally to the oocyte prior to ovulation and are essential for sperm penetration and fertilization. These cells were absent in both Graafian follicles and ovulated oocytes in the oviduct of all groups fed contaminated diets. Oviducts of these mice revealed evidence of epithelial degeneration. These results suggest the female mouse reproductive system is sensitive to organohalogens and illustrate the toxic potential of contaminant mixtures as found in the less contaminated Arctic population. PMID:12775517

Ruby, Sylvia; Mendoza, Luz Tavera; Fournier, Michel; Brousseau, Pauline; Dégas, V

2003-06-13

25

Immunosuppression in mice fed on diets containing beluga whale blubber from the St Lawrence estuary and the Arctic populations.  

PubMed

In order to assess the immunotoxic potential of naturally relevant mixtures of PCBs and other organohalogens, C57Bl/6 mice were fed on diets in which lipids were replaced by blubber of beluga whales from the highly contaminated population of the Saint-Lawrence River, and the less contaminated population from the Arctic. Different ratios of blubber from both sources were mixed in order to allow a dose-response study. Mice were fed for a period of 90 days at the end of which their immunological status was monitored. For general parameters such as body weight, weight of the spleen and the thymus no significant effect of diets were observed. The immunological endpoints such as the blastic transformation of splenocytes and the spleen NK cell activity were not significantly affected by any of the diets compared to control diets. While the different cell subpopulations of peripheral blood and thymus were not affected by the diets, a significant decrease was noted in the CD8+ T cell population in the spleen of mice fed with most of the diets containing beluga blubber. Moreover, the ability of splenic cells to elicit humoral response against sheep red blood cells as well as the potential of peritoneal macrophages to perform phagocytosis were suppressed by all diets containing beluga blubbers. In summary, there was no differences between the groups fed with a blubber diet with low and high organochlorine contamination. However, a clear immunosuppression was demonstrated when these groups were compared to the group fed with beef oil. Despite the fact that we cannot exclude a possible contribution of the fatty acid composition of the beluga blubber to the immunosupression, these results suggest the sensitivity of mouse immune system towards organohalogens, and point out the toxic potential of contaminant mixtures as found in the less contaminated Arctic population. PMID:10720746

Fournier, M; Dégas, V; Colborn, T; Omara, F O; Denizeau, F; Potworowski, E F; Brousseau, P

2000-03-15

26

Dissolved mercury behaviour in the Saint Lawrence estuary  

NASA Astrophysics Data System (ADS)

Dissolved mercury concentrations have been measured in the waters of the St Lawrence estuary. The typical concentration of the riverine end-member is 12·0±3·0 p M; the oceanic end-member samples exhibit a mean mercury concentration of 2·4 p M. The graphical pattern of the relationship between mercury concentration and salinity shows a departure from a dilution line. We suggest that a removal of mercury from the dissolved phase during the estuarine mixing is responsible for this observation. Based on the results, the actual input of dissolved mercury from the St Lawrence River to the Gulf is evaluated to be approximately 0·52 T a -1.

Cossa, Daniel; Gobeil, Charles; Courau, Philippe

1988-02-01

27

14C and 13C Contents of Dissolved Organic Matter in the St. Lawrence Estuary and in a Hydroelectric Reservoir From the Boreal Forest (Quebec)  

NASA Astrophysics Data System (ADS)

In this study we examine the 14C and 13C contents of Dissolved Organic Matter (DOM) in the St. Lawrence River, at its outlet near Quebec City, and in a large hydroelectric reservoir, from the Canadian Boreal forest (Robert-Bourassa reservoir) as a mean to document the origin and residence time of DOM in such large catchments. Samples of DOM were collected bi-weekly at the Quebec City station from November 2001 until November 2002, as part of a geochemical monitoring program of the river, carried out since 1997. At the Robert-Bourassa reservoir, sampling operations took place from July 15 to July 26, 2001. All samples were filtered and acidified on site, and preserved in brown glass bottles at 4° C. Prior to their isotopic analysis, DOM samples were freeze-dried. 13C analyses were made at GEOTOP whereas 14C measurements were performed at the Lawrence Livermore National Laboratory, for samples coming from the St. Lawrence River, and at the Laboratoire d'Hydrologie et de géochimie isotopique of University Paris XI for samples originating from the Robert-Bourassa reservoir. Results are expressed respectively in ‰ vs. V-PDB and in % of modern carbon (% MC; i.e. 13.56 dpm/g C in 1950, for d13C=-25 ‰ ). D13C values averaging -26.3 ± 0.2 ‰ in the St. Lawrence, and -27.1 ± 0.2 ‰ at the Robert-Bourassa reservoir, indicate that DOC originates from terrestrial production, although a slight influence of aquatic DOC is seen in the St. Lawrence river during low water level episodes. In the river, DOC-14C activities range from 97.7 to 106.7 ± 0.5 %, with a mean value of 103.9 ± 0.5 %, whereas samples from Robert-Bourassa reservoir show a range of values between 108.5 and 110.5 ± 0.9 %, with a mean of 109.5 ± 0.9 %. In comparison, measurements made during the late 80's, in a small brook of Ontario, yielded 14C-DOM activities ranging from 113 to 118 % MC (Schiff et al., 1990). Meanwhile, 14C-activity of atmospheric CO2 has decreased of approximately the same proportion. We conclude that soil-derived DOC represents the production of immediately preceding years, notably in the Boreal Forest reservoir, but that contribution of longer residence time DOC from the Great Lakes likely accounts for the slightly lower 14C-DOC values found in the St. Lawrence River. In conclusion, 14C and 13C contents indicate an overall short DOM residence time, thus that the primary production at its origin, and its degradation and transport in the drainage network are fast processes. Reference: Schiff, S. L., R. Aravena, S. E. Trumbore et P. J. Dillon. 1990. Dissolved organic carbon cycling in forested watersheds : a carbon isotope approach. Water Resources Research, 26, no 12, 2949-2957.

Lamontagne, J.; Hélie, J.; Hillaire-Marcel, C.

2004-05-01

28

Sources of particulate and dissolved organic carbon in the St Lawrence River: isotopic approach  

NASA Astrophysics Data System (ADS)

We investigate sources of both dissolved and particulate organic carbon in the St Lawrence River from its source (the Great Lakes outlet) to its estuary, as well as in two of its tributaries. Special attention is given to seasonal interannual patterns by using data collected on a bi-monthly basis from mid-1998 to mid-2003. 13C measurements in dissolved inorganic carbon, dissolved organic carbon (DOC) and particulate organic carbon (POC), as well as molar C : N in particulate organic matter (POM), are used to bring insight into the dynamic between aquatic versus terrigenous sources. In addition, 14C activities of DOC were measured at the outlet of the St Lawrence River to its estuary to assess a mean age of the DOC exported to the estuary. In the St Lawrence River itself, aquatically produced POC dominates terrestrially derived POC and is depleted in 13C by approximately 12 versus dissolved CO2. In the Ottawa River, the St Lawrence River's most important tributary, the present dataset did not allow for convincing deciphering of POC sources. In a small tributary of the St Lawrence River, aquatically produced POC dominates in summer and terrestrially derived POC dominates in winter. DOC seems to be dominated by terrestrially derived organic matter at all sampling sites, with some influence of DOC derived from aquatically produced POC in summer in the St Lawrence River at the outlet of the Great Lakes and in one of its small tributaries. The overall bulk DOC is relatively recent (14C generally exceeding 100% modern carbon) in the St Lawrence River at its outlet to the estuary, suggesting that it derives mainly from recent organic matter from topsoils in the watershed.

Hélie, Jean-François; Hillaire-Marcel, Claude

2006-06-01

29

Assessment of Salinity-Related Mortality of Freshwater Bacteria in the Saint Lawrence Estuary  

Microsoft Academic Search

ThegrowthresponseoffreshwaterbacteriafromtheSt.LawrenceRiver,exposedtobrackishwaters(salinity of 0 to 20‰) from the upper estuary, was assessed by a methodology requiring the combined use of dilution cultures and diffusion chambers. The longitudinal distribution of bacterial abundance in waters within this salinityrangewasalsoexamined.Growthofthefreshwaterbacteriawasreducedby15and50%afterexposure tosalinitiesof10and20‰,respectively.Atlowersalinities,nogrowthreductionwasobserved,andatasalinity of 2‰, growth was even stimulated. Longitudinal distribution data showed that bacterial abundance also peaked at this salinity. In contrast with an earlier hypothesis,

JEAN PAINCHAUD; JEAN-CLAUDE THERRIAULT; ANDLOUIS LEGENDRE

1995-01-01

30

Toxic compounds and health and reproductive effects in St. Lawrence Beluga Whales  

Microsoft Academic Search

An epidemiologic study was carried out over a period of 9 years on an isolated population of beluga whales (Delphinapterus leucas) residing in the St. Lawrence estuary (Quebec, Canada). More than 100 individual deaths were aged, and\\/or autopsied and analyzed for toxic compounds, and the population was surveyed for size and structure. Arctic belugas and other species of whales and

P. Beland; R. Michaud; S. DeGuise; C. Girard; A. Lagace; D. Martineau; Derek C. G. Muir; R. J. Norstorm; E. Pelletier; Sankar Ray

1993-01-01

31

Contamination and Biomarkers in the Great Blue Heron, an Indicator of the State of the St. Lawrence River  

Microsoft Academic Search

In 1996–1997, nine breeding colonies of the great blue heron on the St. Lawrence River and its estuary (Québec, Canada) were\\u000a investigated in the framework of a biomonitoring program. Fledglings from colonies in freshwater were more contaminated with\\u000a mercury, PCBs and many organic contaminants than those from estuarine colonies. The level of contamination in the St. Lawrence\\u000a River is generally below the

Louise Champoux; Jean Rodrigue; Suzanne Trudeau; Monique H. Boily; Philip A. Spear; Alice Hontela

2006-01-01

32

Great Lakes St. Lawrence Seaway System  

NSDL National Science Digital Library

The Great Lakes St. Lawrence Seaway connects the Atlantic Ocean to the Great Lakes, and it was completed in 1959. This website details the activities of the Seaway System, and visitors with an interest in transportation and public policy will find the site both useful and interesting. At the top of the homepage, visitors will find the five primary sections of the site, which include "Management of the Seaway" and "Commercial Shipping". First-time visitors should start at "The Seaway" section. Here they will find the interactive "Gateway to North America" tour, along with information on the System's locks and channels and a nice "Facts and Figures" area. The site also contains thematic collections of information designed for business people, students and educators, and the media. Visitors who wish to stay abreast of System activities can sign up for email updates on the homepage. Francophone users will be glad to learn that the entire site is also available in French.

33

Lobsters and crabs as potential vectors for tunicate dispersal in the southern Gulf of St. Lawrence, Canada  

Microsoft Academic Search

Following anecdotal reports of tunicates on the carapaces of rock crab (Cancer irroratus) and American lobster (Homarus americanus), we evaluated the role of these species and northern lady crab Ovalipes ocellatus as natural vectors for the spread of invasive tunicates in the southern Gulf of St. Lawrence. Several hundred adult specimens of crabs and lobster from two tunicate- infested estuaries

Renée Y. Bernier; Andrea Locke; John Mark Hanson

2009-01-01

34

An empirical approach to the remote sensing of the chlorophyll in the optically complex waters of the Estuary and Gulf of Saint-Lawrence  

Microsoft Academic Search

Data from five research cruises performed between 1997 and 2001 were processed in order to investigate the potential for improving remote sensing algorithms in the Estuary and Gulf of St. Lawrence. Measured in situ parameters included concentration-dependent indicators of the three critical, optically-active constituents, chlorophyll, Coloured Dissolved Organic Matter (CDOM) and Suspended Particulate Matter (SPM). The radiometric dataset used to

K. Mehmet Yayla

2009-01-01

35

Spending Time and Money: Memories of Life in St. Lawrences  

ERIC Educational Resources Information Center

Mabel Cooper and Gloria Ferris spent their early adult life in St. Lawrence's Hospital in Caterham. This was in the late 1950s to early 1970s. This is their memories of how they spent their time. It includes the work they did and leisure. They also write about the tokens that were used in the hospital instead of money.

Abraham, Jane; Cooper, Mabel; Ferris, Gloria

2010-01-01

36

A Study of the St. Lawrence River Ecological Habitat  

ERIC Educational Resources Information Center

Save the River, a grassroots advocacy group established in 1978, lobbies for policies to preserve the upper St. Lawrence River and uses the community's help to keep an eye on the existing habitats. Recently, they procured the Fresh Sound Foundation grant to support the development of new K-12 ecology curricula by local area teachers to educate…

Mesires, Maria

2010-01-01

37

Evaluation of the contamination of marine algae (seaweed) from the St. Lawrence River and likely to be consumed by humans  

SciTech Connect

The goal of the study was to assess the contamination of marine algae (seaweeds) growing in the St. Lawrence River estuary and Gulf of St. Lawrence and to evaluate the risks to human health from the consumption of these algae. Algae were collected by hand at low tide. A total of 10 sites on the north and south shores of the St. Lawrence as well as in Baie des Chaleurs were sampled. The most frequently collected species of algae were Fucus vesiculosus, Ascophyllum nodosum, Laminaria Longicruris, Palmaria palmata, Ulva lactuca, and Fucus distichus. Alga samples were analyzed for metals iodine, and organochlorines. A risk assessment was performed using risk factors. In general, concentrations in St. Lawrence algae were not very high. Consequently, health risks associated with these compounds in St. Lawrence algae were very low. Iodine concentration, on the other hand, could be of concern with regard to human health. Regular consumption of algae, especially of Laminaria sp., could result in levels of iodine sufficient to cause thyroid problems. For regular consumers, it would be preferable to choose species with low iodine concentrations, such as U. lactuca and P. palmata, in order to prevent potential problems. Furthermore, it would also be important to assess whether preparation for consumption or cooking affects the iodine content of algae. Algae consumption may also have beneficial health effects. Scientific literature has shown that it is a good source of fiber and vitamins, especially vitamin B{sub 12}.

Phaneuf, D.; Cote, I.; Dumas, P.; Ferron, L.A.; LeBlanc, A. [CHUQ, Sainte-Foy, Quebec (Canada). Centre de Toxicologie du Quebec] [CHUQ, Sainte-Foy, Quebec (Canada). Centre de Toxicologie du Quebec

1999-02-01

38

Paleoceanography and glacial runoff along the St. Lawrence valley system  

SciTech Connect

Radiocarbon-dated foraminiferal zones in cores from the Gulf of St. Lawrence show that cold saline bottom-water was present in the Goldthwait Sea between 13.6 and 12.9 ka BP and was followed by a salinity minimum from ca. 12.1 to 8.6 ka BP, and then increasing salinity and temperature resulting in the modern, deep, watermass layer by 8 ka BP. During the salinity minimum, glacial Lake St. Lawrence drained east into the Goldthwait Sea before the beginning of the Champlain Sea (11.6--11.4 ka BP). Meltwater flowed through the Champlain and Goldthwait seas between 11 and 10 ka BP when Lake Agassiz water was diverted to the North Atlantic Ocean through Ottawa and St. Lawrence valleys and Gulf of St. Lawrence; this coincides with the decrease in salinity of the Champlain Sea between 10.7 and 10.4 ka BP. A later discharge of meltwater to the North Atlantic Ocean (9.5--8 ka BP) occurred during the final stage of the salinity minimum in the Goldthwait Sea and postdates or coincides with the end of the Champlain Sea. The discharge of meltwater to the North Atlantic Ocean may have cause the freshening of the Champlain Sea. However, it does not appear to have affected the deep water in the Goldthwait Sea and was probably part of the surface outflow to the North Atlantic Ocean through the Gulf of St. Lawrence. The variations in salinity of the deep water of the Goldthwait Sea are related to changes in the composition of the water entering the sea from the North Atlantic Ocean.

Rodrigues, C.G. (Univ. of Windsor, Windsor, Ontario (Canada). Dept. of Geology); Vilks, G. (Bedford Inst. of Oceanography, Dartmouth, NS (United States))

1992-01-01

39

Predispersal seed predation by a coleophorid on the threatened Gulf of St. Lawrence aster  

Microsoft Academic Search

The Gulf of St. Lawrence aster, Symphyotrichum laurentianum (Fernald) G.L. Nesom (Asteraceae), a small annual halophyte endemic to disturbed and highly transient habitats in the Gulf of St. Lawrence, is classified as \\

Royce Steeves; Vazrick Nazari; Jean-François Landry; Christian R. Lacroix

2008-01-01

40

Groundwater quality in the Delaware and St. Lawrence River Basins, New York, 2010  

USGS Publications Warehouse

Water quality in both study areas is generally good, but concentrations of some constituents equaled or exceeded current or proposed Federal or New York State drinking-water standards. The standards exceeded are color (one sample in the St. Lawrence study area), pH (three samples in the Delaware study area), sodium (one sample in the St. Lawrence study area), total dissolved solids (one sample in the St. Lawrence study area), aluminum (one sample in the Delaware study area and one sample in the St. Lawrence study area), iron (seven samples in the St. Lawrence study area), manganese (one sample in the Delaware study area and five samples in the St. Lawrence study area), gross alpha radioactivity (one sample in the St. Lawrence study area), radon-222 (10 samples in the Delaware study area and 14 samples in the St. Lawrence study area), and bacteria (

Nystrom, Elizabeth A.

2012-01-01

41

Supracrustal faults of the St. Lawrence rift system, Québec: kinematics and geometry as revealed by field mapping and marine seismic reflection data  

NASA Astrophysics Data System (ADS)

The St. Lawrence rift system from the Laurentian craton core to the offshore St. Lawrence River system is a seismically active zone in which fault reactivation is believed to occur along late Proterozoic to early Paleozoic normal faults related to the opening of the Iapetus ocean. The rift-related faults fringe the contact between the Grenvillian basement to the NW and Cambrian-Ordovician rocks of the St. Lawrence Lowlands to the SE and occur also within the Grenvillian basement. The St. Lawrence rift system trends NE-SW and represents a SE-dipping half-graben that links the NW-SE-trending Ottawa-Bonnechère and Saguenay River grabens, both interpreted as Iapetan failed arms. Coastal sections of the St. Lawrence River that expose fault rocks related to the St. Lawrence rift system have been studied between Québec city and the Saguenay River. Brittle faults marking the St. Lawrence rift system consist of NE- and NW-trending structures that show mutual crosscutting relationships. Fault rocks consist of fault breccias, cataclasites and pseudotachylytes. Field relationships suggest that the various types of fault rocks are associated with the same tectonic event. High-resolution marine seismic reflection data acquired in the St. Lawrence River estuary, between Rimouski, the Saguenay River and Forestville, identify submarine topographic relief attributed to the St. Lawrence rift system. Northeast-trending seismic reflection profiles show a basement geometry that agrees with onshore structural features. Northwest-trending seismic profiles suggest that normal faults fringing the St. Lawrence River are associated with a major topographic depression in the estuary, the Laurentian Channel trough, with up to 700 m of basement relief. A two-way travel-time to bedrock map, based on seismic data from the St. Lawrence estuary, and comparison with the onshore rift segment suggest that the Laurentian Channel trough varies from a half-graben to a graben structure from SW to NE. It is speculated that natural gas occurrences within both the onshore and offshore sequences of unconsolidated Quaternary deposits are possibly related to degassing processes of basement rocks, and that hydrocarbons were drained upward by the rift faults.

Tremblay, Alain; Long, Bernard; Massé, Manon

2003-07-01

42

Relationships between metallothionein induction, cadmium, copper and zinc levels and environmental parameters in the soft shell clam Mya arenaria in the Saguenay fjord and the St. Lawrence River maritime estuary  

Microsoft Academic Search

Physiological status of Mya arenaria is threatened in the Saguenay-Saint Lawrence system due to inputs of many kinds of pollutants from anthropogenic and industrial origins. Investigations of the health of M. arenaria were carried out using metallothioneins concentrations as biomarkers of metallic contamination in relation with concentrations of metals.

Jocelyne Pellerin; Jean-Claude Amiard

2008-01-01

43

Bioassessment of Benthic Macroinvertebrates in Wetland Habitats of Lake Saint-Pierre (St. Lawrence River)  

Microsoft Academic Search

We evaluated the potential of vegetation and sediment habitats in wetlands of the St. Lawrence River for developing a macroinvertebrate bioassessment program with reference conditions. During September 2004, we collected macroinvertebrates in emergent vegetation and sediment in both fluvial sites (reference) and tributary-plume sites (impacted) in waters of the north and south shores of Lake Saint-Pierre (St. Lawrence River). In

Laure Tall; Ginette Méthot; Alain Armellin; Bernadette Pinel-Alloul

2008-01-01

44

Pristine Lake Saint-François, St. Lawrence River: Hydrodynamic Simulation and Cumulative Impact  

Microsoft Academic Search

Lake Saint-François is a fluvial lake of the St. Lawrence system which is used for hydropower production and commercial navigation. For 150 years, it was dredged and dammed regularly without any impact analysis being made. The cumulative impact of dredging and damming on large rivers such as the St. Lawrence is an issue with only qualitative answers. Bidimensional hydrodynamics was

Jean Morin; Paul Boudreau; Yves Secretan; Michel Leclerc

2000-01-01

45

Organochlorine and Metal Contaminants in Traditional Foods from St. Lawrence Island, Alaska  

Microsoft Academic Search

Marine mammals (bowhead whale, walrus, and various seals) constitute the major component of the diet of the Yupik people of St. Lawrence Island, Alaska. St. Lawrence Island residents have higher serum concentrations of polychlorinated biphenyls (PCB) than in the general U.S. population. In order to determine potential sources, traditional food samples were collected from 2004 to 2009 and analyzed for

Gretchen Welfinger-Smith; Judith L. Minholz; Sam Byrne; Vi Waghiyi; Jesse Gologergen; Jane Kava; Morgan Apatiki; Eddie Ungott; Pamela K. Miller; John G. Arnason; David O. Carpenter

2011-01-01

46

Influence of local variations in the ionic ratios on the density of seawater in the St. Lawrence area  

NASA Astrophysics Data System (ADS)

In order to verify the validity of the equations of state of seawater in their application to natural waters with low salinity, the chlorinity and conductivity of 144 samples from the St. Lawrence Gulf and Estuary and from the Saguenay Fjord were measured and used in several equations of state to calculate the density. These results were then compared with direct measurements with a densimeer on the same samples. The smallest deviations from the measured values were obtained with the equation of state of COX, CULKIN and RILEY, Deep-Sea Research, 14, 203-220 (1967), and COX, MCCARTNEY and CULKIN, Deep-Sea Research, 17, 679-689 (1970). The method of MILLEROin Marine Chemistry in the Coastal Environment, ACS Symposium, 18, 25-55 (1975) and Thalassia Jugoslavica, 14, 1-46 (1978), which uses the concept of "total salinity", could not be applied successfully to the waters in the St. Lawrence Estuary. A good agreement between measured and calculated values was obtained with the nine-component seawater model of POISSON, Thése de doctorat d'état ès-sciences physiques, Université Pierre et Marie Curie, Paris (1978).

Poisson, A.; Lebel, J.; Brunet, C.

1980-10-01

47

Three-dimensional modeling of hydrodynamic processes in the St. Lucie Estuary  

Microsoft Academic Search

Comparing with the studies on large estuarine systems, such as the Chesapeake Bay and the San Francisco Bay, the processes of stratification and transport in small and shallow estuaries are relatively less studied. The St. Lucie Estuary (SLE) is a riverine estuary located on the east coast of south Florida. It is small and shallow, with mean depth of 2.4m.

Zhen-Gang Ji; Guangdou Hu; Jian Shen; Yongshan Wan

2007-01-01

48

46 CFR 401.405 - Basic rates and charges on the St. Lawrence River and Lake Ontario.  

Code of Federal Regulations, 2010 CFR

...and charges on the St. Lawrence River and Lake Ontario. 401.405 Section...and charges on the St. Lawrence River and Lake Ontario. Except as provided...registered pilots in the St. Lawrence River and Lake Ontario. (a) Area 1...

2009-10-01

49

46 CFR 401.405 - Basic rates and charges on the St. Lawrence River and Lake Ontario.  

Code of Federal Regulations, 2010 CFR

...and charges on the St. Lawrence River and Lake Ontario. 401.405 Section...and charges on the St. Lawrence River and Lake Ontario. Except as provided...registered pilots in the St. Lawrence River and Lake Ontario. (a) Area 1...

2010-10-01

50

Modelling spatial distribution of epibenthic communities in the Gulf of St. Lawrence (Canada)  

NASA Astrophysics Data System (ADS)

Correlative habitat models using relationships between marine organisms and their surrounding environment can be used to predict species distribution, and the results can assist management of human activities sharing the marine space (e.g. fisheries, MPAs, tourism). Here, epi-benthic megafauna was sampled at 755 stations in the Lower Estuary and Northern Gulf of St. Lawrence (EGSL) each summer between 2006 and 2009. We combined various types of multivariate analyses to 1) describe the structure and spatial distribution of benthic communities, 2) analyse the relationship between these communities and environmental parameters, and subsequently 3) build a community distribution model to predict the spatial distribution of the communities, creating community distribution maps covering the entire area to be used for marine management and conservation. We identified distinct benthic communities in the study area that closely correlate with the 200 m depth contour and with major environmental variables. A redundancy analysis revealed that communities were associated with depth, oxygen saturation, temperature, bottom current, seabed uniformity, distance to coast and type of sediment. Together these environmental descriptors explained 38% of the variation in megafaunal community composition. The environmental variables were used to build a community distribution model using generalized linear models to predict high and low suitability zones of each community in the EGSL.

Moritz, Charlotte; Lévesque, Mélanie; Gravel, Dominique; Vaz, Sandrine; Archambault, Diane; Archambault, Philippe

2013-04-01

51

A Detailed Magnetic Survey of the St. Lawrence River: Oak Point to Lake Ontario, New York.  

National Technical Information Service (NTIS)

Measurements of the total intensity of the earth's magnetic field in the St. Lawrence River between Oak Point and Lake Ontario indicate magnetic anomalies of high magnitude and steep gradients due to rocks of varying magnetic susceptibility in the Precamb...

F. Revetta J. Cardinal

1979-01-01

52

Water Pollution Problems and Improvement Needs Lake Ontario and St. Lawrence River Basins.  

National Technical Information Service (NTIS)

The report summarizes the water pollution problems of the United States water of Lake Ontario and the St. Lawrence River and their tributaries. It identifies the causes of these problems or sources of pollution, discusses the improvements needed, and pres...

1968-01-01

53

Field measurements of ship waves along the St. Lawrence river waterway, Canada  

Microsoft Academic Search

Coastal erosion along the St. Lawrence river waterway in Quebec, Canada, represents a hazard to local communities living along the river banks, as well as to the local fauna habitat. The purpose of this study is to assess the potential impact of longer containerships on riverbank erosion and recession at critical sites along the Saint Lawrence river waterway. A field

S. Gharbi; S. Hamdi; G. Valkov; I. Nistor

2008-01-01

54

Report on the Immediate Water Pollution Control Needs for the Interstate and Intrastate Waters of the St. Lawrence Region.  

National Technical Information Service (NTIS)

The report reviews the water pollution problems in the St. Lawrence Region, which is defined to include all streams draining to the St. Lawrence River from the St. Regis River in New York on the west to Lake Memphremagog in Vermont on the east. The major ...

1967-01-01

55

78 FR 40260 - International Joint Commission: Public Comment on a Proposal for Lake Ontario and St. Lawrence...  

Federal Register 2010, 2011, 2012, 2013

...Comment on a Proposal for Lake Ontario and St. Lawrence River Regulation The International...Ontario and in the St Lawrence River as far downstream as Lake St. Pierre. Although water...favorable conditions on the lake and river for water intakes,...

2013-07-03

56

Analytical Modeling of Groundwater Seepages to St. Lucie Estuary  

NASA Astrophysics Data System (ADS)

In this paper, six analytical models describing hydraulic interaction of stream-aquifer systems were applied to St Lucie Estuary (SLE) River Estuaries. These are analytical solutions for: (1) flow from a finite aquifer to a canal, (2) flow from an infinite aquifer to a canal, (3) the linearized Laplace system in a seepage surface, (4) wave propagation in the aquifer, (5) potential flow through stratified unconfined aquifers, and (6) flow through stratified confined aquifers. Input data for analytical solutions were obtained from monitoring wells and river stages at seepage-meter sites. Four transects in the study area are available: Club Med, Harbour Ridge, Lutz/MacMillan, and Pendarvis Cove located in the St. Lucie River. The analytical models were first calibrated with seepage meter measurements and then used to estimate of groundwater discharges into St. Lucie River. From this process, analytical relationships between the seepage rate and river stages and/or groundwater tables were established to predict the seasonal and monthly variation in groundwater seepage into SLE. It was found the seepage rate estimations by analytical models agreed well with measured data for some cases but only fair for some other cases. This is not unexpected because analytical solutions have some inherently simplified assumptions, which may be more valid for some cases than the others. From analytical calculations, it is possible to predict approximate seepage rates in the study domain when the assumptions underlying these analytical models are valid. The finite and infinite aquifer models and the linearized Laplace method are good for sites Pendarvis Cove and Lutz/MacMillian, but fair for the other two sites. The wave propagation model gave very good agreement in phase but only fairly agreement in magnitude for all four sites. The stratified unconfined and confined aquifer models gave similarly good agreements with measurements at three sites but poorly at the Club Med site. None of the analytical models presented here can fit the data at this site. To give better estimates at all sites numerical modeling that couple river hydraulics and groundwater flow involving less simplifications of and assumptions for the system may have to be adapted.

Lee, J.; Yeh, G.; Hu, G.

2008-12-01

57

Time Series Analysis of Water Level and Temperature in the St Louis River Estuary  

EPA Science Inventory

Pressure and temperature loggers were deployed at 9 sites in the St Louis River estuary between 6/23 10/31 2011. A reference sensor was place on the shore to correct pressure data. Sensors were paced at ...

58

Cultural Encounters at St. Lawrence University. Final FIPSE Report.  

ERIC Educational Resources Information Center

This final report of a three-year project at Saint Lawrence University (NY), entitled the Cultural Encounters Project, details a faculty and curriculum development project that focused on particular issues in global or international studies. The project grew out of the so-called "cultural wars," or clash between those who sought to retain an…

Stoddard, Eve W.

59

Basis of comparison Great Lakes-St. Lawrence River system. Technical memo  

SciTech Connect

A 90-year set of lake levels and flows has been developed that reflects a consistent hydraulic regime in the Great Lakes-St. Lawrence Riversystem. The hydraulic regime is defined by the diversion rates into and out of the system, consumptive use withdrawals from the system, the time series of water supplies to the system, outlet conditions of each lake, flow retardation due to ice or weeds in the connecting channels, initial starting elevations for the simulation, the hydraulic condition of the St. Lawrence River, and tidal levels at its outlet. These levels and flows can be used as a reference for assessing the effects of modified lake regulation and climate change.

Lee, D.H.

1993-04-01

60

Influence of summer water-level variability on St. Lawrence River-wetland fish assemblages  

USGS Publications Warehouse

Water-level and associated variability are substantial influences on wetland and shallow aquatic communities. The Akwesasne Wetland Complex is an extensive St. Lawrence River system affected by water regulation. The responses of fish assemblages to short-term summer water-level variation were examined throughout this section of the St. Lawrence River and its tributaries. An influence of water-level variability was detected on abundance of three common species [bluntnose minnow (Pimephales notatus), rock bass (Amboplites rupestris), and white sucker (Catastomus commersonii)] and explained 30-44% of variation. This influence has implications for water regulation and natural resource management, and a larger scope evaluation may reveal more extensive effects.

McKenna, Jr. , J. E.; Barkley, J. L.; Johnson, J. H.

2008-01-01

61

Modeling the formation and circulation processes of water masses and sea ice in the Gulf of St. Lawrence, Canada  

NASA Astrophysics Data System (ADS)

The seasonal cycle of water masses and sea ice in the Gulf of St. Lawrence is examined using a three-dimensional coastal ice-ocean model with realistic tidal, atmospheric, hydrologic, and oceanic forcing. The model includes a level 2.5 turbulent kinetic energy equation. A model simulation over 1997-1998 is verified against available data on sea ice, temperature, and salinity. The results demonstrate a consistent seasonal cycle in atmosphere-ocean exchanges and the formation and circulation of water masses and sea ice. The accuracy of radiative, momentum, and sensible heat exchanges at the sea surface, and the production of turbulent kinetic energy from winds and tides, are critical to the accuracy of the modeled circulation. The analysis of the mean error on near-surface temperature and salinity in the late summer and fall using standard bulk exchange coefficients and radiation (about 1°C too cold and 1 salinity unit too fresh) shows the tradeoff between tidal mixing at the head of the Laurentian Channel, and wind-driven circulation and mixing in the surface waters. The results suggest year-long stratification in the estuary and northwestern Gulf, with little mixing except near the head region, where relatively deep warmer waters are mixed to the surface during winter, and cold intermediate waters are efficiently withdrawn during summer. The results suggest that the summer cold waters found at intermediate depths in the estuary and northwestern Gulf are not formed in situ. A significant fraction of these waters enters through the Strait of Belle Isle in wintertime, eventually reaching the estuary within about 6 months.

Saucier, FrançOis J.; Roy, FrançOis; Gilbert, Denis; Pellerin, Pierre; Ritchie, Harold

2003-08-01

62

A threatened beluga (Delphinapterus leucas) population in the traffic lane: vessel-generated noise characteristics of the Saguenay-St. Lawrence Marine Park, Canada.  

PubMed

The threatened resident beluga population of the St. Lawrence Estuary shares the Saguenay-St. Lawrence Marine Park with significant anthropogenic noise sources, including marine commercial traffic and a well-established, vessel-based whale-watching industry. Frequency-dependent (FD) weighting was used to approximate beluga hearing sensitivity to determine how noise exposure varied in time and space at six sites of high beluga summer residency. The relative contribution of each source to acoustic habitat degradation was estimated by measuring noise levels throughout the summer and noise signatures of typical vessel classes with respect to traffic volume and sound propagation characteristics. Rigid-hulled inflatable boats were the dominant noise source with respect to estimated beluga hearing sensitivity in the studied habitats due to their high occurrence and proximity, high correlation with site-specific FD-weighted sound levels, and the dominance of mid-frequencies (0.3-23 kHz) in their noise signatures. Median C-weighted sound pressure level (SPL(RMS)) had a range of 19 dB re 1 ?Pa between the noisiest and quietest sites. Broadband SPL(RMS) exceeded 120 dB re 1 ?Pa 8-32% of the time depending on the site. Impacts of these noise levels on St. Lawrence beluga will depend on exposure recurrence and individual responsiveness. PMID:22225023

McQuinn, Ian H; Lesage, Véronique; Carrier, Dominic; Larrivée, Geneviève; Samson, Yves; Chartrand, Sylvain; Michaud, Robert; Theriault, James

2011-12-01

63

Efficiency and ghost fishing of snow crab ( Chionoecetes opilio) traps in the Gulf of St. Lawrence  

Microsoft Academic Search

Experiments were conducted in the southwestern Gulf of St. Lawrence from 1988 to 1993 to: (1) evaluate the catch performance of three types of conventional commercial snow crab traps; (2) evaluate the catch rates of soft-shelled crabs in normal and modified conical traps; and (3) investigate ghost fishing by lost traps. Our results showed that pyramidal and conical traps captured

M Hébert; G Miron; M Moriyasu; R Vienneau; P DeGrâce

2001-01-01

64

Development of Freezer-Storage Facilities at Savoonga, St. Lawrence Island, Alaska.  

National Technical Information Service (NTIS)

The report covers a long project (April 1968 to April 1974) involving the design, construction, and testing of a large naturally-powered freezer for mammalian meat storage at Savoonga, St. Lawrence Island, Alaska. The story of the freezer is also long, bu...

T. Wentink L. Leonard P. R. Johnson

1975-01-01

65

Community interactions affecting the relative abundances of native and invasive amphipods in the St. Lawrence River  

Microsoft Academic Search

The Eurasian amphipod Echinogammarus ischnus is reportedly replacing the common native amphipod Gammarus fasciatus in the Great Lakes - St. Lawrence River system. A potential mechanism for this replacement is competition mediated by resident species. Other Eurasian invaders, dreissenid mussels (Dreissena polymorpha and Dreissena bugensis), dominate rocky substrates throughout the system and might be promoting the rapid expansion of E.

M. E. Palmer; Anthony Ricciardi

2005-01-01

66

Physical factors affecting the relative abundance of native and invasive amphipods in the St. Lawrence River  

Microsoft Academic Search

The Ponto-Caspian amphipod Echinogammarus ischnus (Stebbing, 1899) is reportedly replacing the North American amphipod Gammarus fasciatus Say, 1818, in the lower Great Lakes, but the two species appear to coexist in the upper St. Lawrence River several years after invasion by E. ischnus. A multi-site survey in the river between Lake Ontario and Montreal (Quebec) found that E. ischnus and

M. E. Palmer; A. Ricciardi

2004-01-01

67

A Study of the Effects of Inland Freight Rates and Services on the St. Lawrence Seaway.  

National Technical Information Service (NTIS)

The report examines selected railroad rates on commodities moving from the Great Lakes-St. Lawrence Seaway hinterland to Great Lakes, North Atlantic, and southern ports. A comparative analysis is made of rate and cost data for the sample regional commodit...

1971-01-01

68

Diel and lateral patterns of zooplankton distribution in the St. Lawrence River  

Microsoft Academic Search

While the four-dimensional nature of river ecosystems has been recognized for nearly two decades, the role of lateral complexity has rarely been factored into studies of zooplankton ecology. We examined the importance of hydrologic retention areas (slackwaters) near islands and embayments of the St. Lawrence River for densities, fecundity, and diel migration of planktonic microcrustaceans. Densities of cladocera and copepods

Andrew F. Casper; James H. Thorp

2007-01-01

69

Review of neurobehavioral deficits and river fish consumption from the Tapajós (Brazil) and St. Lawrence (Canada)  

Microsoft Academic Search

Our research group is carrying out studies on neurobehavioral changes associated with eating fish from the Upper St. Lawrence River (Québec, Canada) and the Lower Tapajós River (Brazilian Amazon). Here, these studies are reviewed with respect to exposure, effects and intervention. Although mercury (Hg) levels in piscivorous fish are similar in both regions, in the Amazon, fish constitutes the dietary

Donna Mergler

2002-01-01

70

Comparison of Lake Ontario and St. Lawrence River hydrologic droughts and their relationship to climate indices  

NASA Astrophysics Data System (ADS)

Five characteristics (intensity or magnitude, duration, frequency, timing, and variability) of drought, defined using the threshold level method (TLM) and recorded in mean annual water levels in Lake Ontario and the St. Lawrence River from 1918 to 2010, were compared. Timing is the only characteristic that is different for the two water bodies. For Lake Ontario, the most intense drought occurred in the 1930s, whereas in the St. Lawrence River, intense droughts took place in the 1960s and 2000s. The Lake Ontario drought produced two shifts in mean before (decrease) and after (increase) the 1930s. The change in variance that took place in the 1960s is thought to be related to the construction of locks during the digging of the seaway. The droughts that affected the St. Lawrence River had no impact on the stationarity (mean and variance) of the annual mean water level series. Analysis of the correlation between drought severity and climate indices revealed that years characterized by very weak to moderate drought are significantly correlated with PDO (Pacific Decadal Oscillation), while those characterized by intense drought are correlated with NAO (North Atlantic Oscillation). Both climate indices are negatively correlated with Lake Ontario water levels, while they are positively correlated with St. Lawrence River levels. The study suggests that NAO may be used to predict the driest years for the two water bodies.

Biron, Stacey; Assani, Ali A.; Frenette, Jean-Jacques; Massicotte, Philippe

2014-02-01

71

A Practical Grammar of the St. Lawrence Island/Siberian Yupik Eskimo Language. Second Edition.  

ERIC Educational Resources Information Center

This book deals with the Central Siberian Yupik Eskimo language as spoken on St. Lawrence Island, Alaska, an island near the Bering Strait and on the tip of the Asian mainland opposite Russia. This book has been used with college-level classes composed of a mixture of Yupik speakers and well-prepared non-speakers (people who have studied other,…

Jacobson, Steven A.

72

Constraints on Lake Agassiz discharge through the late-glacial Champlain Sea (St. Lawrence Lowlands, Canada) using salinity proxies and an estuarine circulation model  

USGS Publications Warehouse

During the last deglaciation, abrupt freshwater discharge events from proglacial lakes in North America, such as glacial Lake Agassiz, are believed to have drained into the North Atlantic Ocean, causing large shifts in climate by weakening the formation of North Atlantic Deep Water and decreasing ocean heat transport to high northern latitudes. These discharges were caused by changes in lake drainage outlets, but the duration, magnitude and routing of discharge events, factors which govern the climatic response to freshwater forcing, are poorly known. Abrupt discharges, called floods, are typically assumed to last months to a year, whereas more gradual discharges, called routing events, occur over centuries. Here we use estuarine modeling to evaluate freshwater discharge from Lake Agassiz and other North American proglacial lakes into the North Atlantic Ocean through the St. Lawrence estuary around 11.5 ka BP, the onset of the Preboreal oscillation (PBO). Faunal and isotopic proxy data from the Champlain Sea, a semi-isolated, marine-brackish water body that occupied the St. Lawrence and Champlain Valleys from 13 to 9 ka, indicate salinity fell about 7-8 (range of 4-11) around 11.5 ka. Model results suggest that minimum (1600 km3) and maximum (9500 km3) estimates of plausible flood volumes determined from Lake Agassiz paleoshorelines would produce the proxy-reconstructed salinity decrease if the floods lasted <1 day to 5 months and 1 month to 2 years, respectively. In addition, Champlain Sea salinity responds very quickly to the initiation (within days) and cessation (within weeks) of flooding events. These results support the hypothesis that a glacial lake flood, rather than a sustained routing event, discharged through the St. Lawrence Estuary during the PBO. ?? 2011 Elsevier Ltd.

Katz, B.; Najjar, R. G.; Cronin, T.; Rayburn, J.; Mann, M. E.

2011-01-01

73

Year-Class Formation of Upper St. Lawrence River Northern Pike  

Microsoft Academic Search

Variables associated with year-class formation in upper St. Lawrence River northern pike Esox lucius were examined to explore population trends. A partial least-squares (PLS) regression model (PLS 1) was used to relate a year-class strength index (YCSI; 1974–1997) to explanatory variables associated with spawning and nursery areas (seasonal water level and temperature and their variability, number of ice days, and

Brian M. Smith; John M. Farrell; H. Brian Underwood; Stephen J. Smith

2007-01-01

74

Impact of the( Dreissena ) invasion on native unionid bivalves in the upper St. Lawrence River  

Microsoft Academic Search

Introduced Eurasian mussels (Dreissena polymorpha and Dreissena bugensis) colonized native unionid bivalves in the upper St. Lawrence River in the early 1990s. From 1992 to 1995, we examined the infestation and impact of Dreissena on unionids at several sites near the Island of MontrØal. Unionids suffered heavy (90ñ100%) mortality at sites where Dreissena occurred in high densities (i.e., 4000 ñ

A. Ricciardi; F. G. Whoriskey; J. B. Rasmussen

1996-01-01

75

Budget and sources of suspended sediment transported in the St. Lawrence River, Canada  

Microsoft Academic Search

A mass balance budget of the suspended sediment in the St. Lawrence River was established for the sector stretching from Cornwall, Ontario, to Quebec City, Quebec, for the period 1989-1993. The approach consisted of analysing the amount of sediment contributed by the different tributaries, on a watershed-by-watershed basis, through sediment concentration-discharge models incorporating more than 4000 data points collected since

Bernard Rondeau; D. Cossa; P. Gagnon; L. Bilodeau

2000-01-01

76

Feeding Ecology of Juvenile Lake Sturgeon in the St. Lawrence River System  

Microsoft Academic Search

We examined the diet of juvenile lake sturgeon Acipenser fulvescens at five sites in the St. Lawrence River, including two sites in major tributaries (Des Prairies and L'Assomption rivers), two main-stem sites located upstream (Verchères and Sorel-Berthier islands), and one site located downstream in the estuarine transition zone (ETZ). The benthic fauna was sampled at all sites except in the

Pedro Nilo; Serge Tremblay; Aline Bolon; Julian Dodson; Pierre Dumont; Réjean Fortin

2006-01-01

77

Temporal changes in wetland landscapes of a section of the St. Lawrence River, Canada  

Microsoft Academic Search

Historical aerial photographs (from 1946 through 1983) were used to study and describe the nature and extent of changes in\\u000a wetland vegetation of a section of the St. Lawrence River and to evaluate the relative importance of water level, fire, and\\u000a vegetational development as causal factors of these historical changes. Data were encoded and analyzed using a geographical\\u000a information system,

Martin Jean; André Bouchard

1991-01-01

78

Environmental contaminants in tissues of a neonate St Lawrence Beluga Whale ( Delphinapterus leucas)  

Microsoft Academic Search

Tissue samples of brain, kidney, liver, and blubber from a neonate St Lawrence beluga whale were analyzed for ortho and non-ortho polychlorinated (PCB) congeners, organochlorine (OC) compounds, polychlorinated dibenzo-p-dioxins and -dibenzofurans (PCDD\\/Fs), and total mercury. As ?-globulins, which indicate presence of colostrum, were not found in serum of the live neonate, it was unlikely that there had been lactational transfer

J. M Gauthier; É Pelletier; C Brochu; S Moore; C. D Metcalfe; P Béland

1998-01-01

79

Annual Records of Toxic phytoplankton and PSP toxins in the Gulf of St. Lawrence, Quebec.  

NSDL National Science Digital Library

This website provides access to annual records of the abundance of phytoplankton species and physical-chemical parameters of seawater at monitoring stations in the Gulf of St. Lawrence, Quebec, Canada. Users may choose a particular station and the year to view the data (which are presented in MS-Excel format, in French). The webpage also provides a link to a map displaying the locations of the sampling stations.

2010-07-06

80

Assessment of Contamination and Biomarker Responses in Two Species of Herons on the St. Lawrence River  

Microsoft Academic Search

This study was undertaken to validate potential biomarkers of exposure and effects due to chemical contaminants in breedingcolonies of the Great Blue Heron and the Black-crowned Night-Heron on the St. Lawrence River. Eggs and fledglings from both species were collected from many colonies along theRiver. The fledglings from colonies in freshwater and brackishwater were more contaminated by mercury and PCBs

Louise Champoux; Jean Rodrigue; Jean-Luc DesGranges; Suzanne Trudeau; Alice Hontela; Monique Boily; Philip Spear

2002-01-01

81

Influence of the St. Lawrence Island Polynya upon the Bering Sea benthos  

NASA Astrophysics Data System (ADS)

The influence of a polynya, a persistent ice-free region, on water column production and subsequent transport to the shallow continental shelf benthos of the Bering Sea was evaluated by studying spatial patterns of organic material deposition, benthic biomass, community sediment metabolism, benthic population structure, and other potential indicators of enhanced organic carbon transport to benthic communities underlying the St. Lawrence Island Polynya. Despite suggestions that polynyas may be important localized centers of primary production in polar waters, we found that the St. Lawrence Island Polynya does not obviously enhance the biomass of benthic communities directly below the polynya. However, southward flowing, baroclinic currents generated as a result of brine injection at the polynya edge do appear to have an influence on the biomass and ecological structure of Bering Sea benthic communities south of St. Lawrence Island. These currents appear to affect mean sediment oxygen consumption, surface organic carbon/nitrogen ratios, total organic content, and bottom water ammonia by sweeping phytodetrital matter south and to the west of the island. A particle-reactive, short-lived, natural radioisotope, 7Be, used as an indicator of rapid (days to weeks) deposition of particulate material from the water column, was detected only in surface sediments to the southwest of the island, indicating enhancement of particle deposition to the southwest of the island. Finally, the 18O content of tunicate cellulose was highest in the polynya region, consistent with increased filter feeding in the late winter when the polynya is present, and presumably promoting primary production in the open water. The Anadyr Current, consisting of nutrient-rich, deeper Bering Sea water that is upwelled onto the shelf in the Gulf of Anadyr, flows west to east in the region south of St. Lawrence Island throughout the year and is the major forcing function for high production in the region. The interaction of Anadyr Water with the winter/spring ephemeral polynya and associated baroclinic currents combine to positively influence benthic communities.

Grebmeier, Jacqueline M.; Cooper, Lee W.

1995-03-01

82

Research management in the Great Lakes and St. Lawrence River basins: Challenges and opportunities  

SciTech Connect

Research management in the Great Lakes and St. Lawrence River basins is both challenging and filled with opportunities. From the perspective of public health practice, research management is more than just research managers managing discrete programs; it requires everyone involved in the process to become active participants, including researchers, communities,l potential interest groups, policymakers, and other stakeholders. Agencies, organizations, and individuals responsible for managing research and resources in the Great Lakes and St. Lawrence River basins are facing problems of decreased research funding, data gaps, and research quality. Managers of research and resources in the basins face many challenges as they address these problems. They are challenged with strengthening the link between research and management in the face of decreasing resources and increasing expectations of results and findings while extending those results and findings to public health practice. A number of actions and activities have been proposed that can lead to better management of constrained programs, pooled resources, partnerships, targeted priorities, and improved effectiveness. With guidance and assistance from the International Joint Commission (IJHC), research managers in the Great Lakes and St. Lawrence River basins who have initiated and maintained traditional research programs based on sound science are now adopting different and innovative management strategies.

Rosa, C.T. de; Rosemond, Z.A.; Cibulas, W. [Dept. of Health and Human Services, Atlanta, GA (United States). Agency for Toxic Substances and Disease Registry] [Dept. of Health and Human Services, Atlanta, GA (United States). Agency for Toxic Substances and Disease Registry; Gilman, A.P. [Health Canada, Ottawa, Ontario (Canada). Environmental Health Directorate] [Health Canada, Ottawa, Ontario (Canada). Environmental Health Directorate

1999-04-01

83

Budget and sources of suspended sediment transported in the St. Lawrence River, Canada  

NASA Astrophysics Data System (ADS)

A mass balance budget of the suspended sediment in the St. Lawrence River was established for the sector stretching from Cornwall, Ontario, to Quebec City, Quebec, for the period 1989-1993. The approach consisted of analysing the amount of sediment contributed by the different tributaries, on a watershed-by-watershed basis, through sediment concentration-discharge models incorporating more than 4000 data points collected since 1983. Lake Ontario contributes less than 3% of the particulate load at Quebec City, while St. Lawrence tributaries on the south and north shores contribute 19% and 13%, respectively, of the sediment load. Our findings indicate that nearly 65% of the suspended sediments come from erosion of the bed and banks of the St. Lawrence River. This finding is broadly supported by numerous geomorphological and sedimentological observations and is consistent with the geological history of the river and the structures built on its banks in recent decades. Upstream-downstream mass balance studies conducted on individual river sectors indicate that the sources of erosion are located mainly in the Beauharnois Canal region, between Montreal and Les Grèves, and further downstream, between the outlet of Lake Saint-Pierre and Portneuf.

Rondeau, Bernard; Cossa, D.; Gagnon, P.; Bilodeau, L.

2000-01-01

84

Glacial Lake Outflow via the St. Lawrence Pathway Prior to the Champlain Sea Invasion and During the Younger Dryas  

NASA Astrophysics Data System (ADS)

When the Laurentide Ice Sheet receded north of the Adirondacks, Glacial Lake Frontenac overflowed to Glacial Lake Vermont (Coveville phase)-Albany. The water level of Lake Frontenac fell by about 90 m, as a result of the drawdown, glacio-isostatic rebound and outflow of Lake Vermont-Albany through the Hudson Valley to the North Atlantic Ocean. Lake level stabilized to form the Belleville, Upper Fort-Ann, post-Sherbrooke phase of glacial lakes post-Iroquois, Vermont and Memphremagog, respectively. Initially, the confluent fresh-water body extended from the Lake Ontario basin into the upper St. Lawrence Valley, Lake Champlain basin and along the Appalachian piedmont. The outlet of the lake was the Upper Fort-Ann sill, along the Hudson pathway (Lake Albany). The expansion of the lake was time transgressive and related to the regional ice retreat. As the lake expanded across the lowlands, into the Ottawa and central St. Lawrence valleys, and along the Appalachian piedmont, its level fell by about 20 m, from the Belleville to the Trenton strandlines on the western side of the Adirondacks, and about 26 m (Rayburn, 2004) from the Upper to the Lower Fort-Ann strandlines in the Lake Champlain basin. The extent of the lake during its final stage is estimated at about 30,000 km2. Varves deposited in the deeper parts of the lake are characterized by the ostracode Candona subtriangulata. Varve counts from several reference sections provide an approximate duration for the glaciolacustrine phase in different parts of the lowlands. They range from about 50 to 30 yr in the lower Ottawa Valley, where the estimated depth was 180 to 200 m, about 100 yr along the Appalachian piedmont and, tentatively, to more than 160 yr in the Lake Champlain basin (Rayburn et al., 2005). The lake overflowed/drained suddenly to the east, toward the western arm of the Goldthwait Sea, in the Estuary and Gulf of St. Lawrence, and hence into the North Atlantic Ocean. During this event, the water level fell by about 50 to 40 m to the highest strandline of the Champlain Sea. The timing and volume of this fresh-water discharge are quantified to allow assessment of its potential impact on the thermohaline circulation of the North Atlantic Ocean, and whether it could have triggered the cold Younger Dryas episode. The overflow occurred within a one-year span between 11.2 and 10.9 14C ka BP or 13.2 and 12.85 cal ka BP, close to the onset of the Younger Dryas cold interval. The total freshwater outflow through the St. Lawrence pathway comprised the one-year overflow phase (about 1500 km3), an early mixing phase of fresh and marine waters in the Champlain Sea domain (about 400 km3 for several years), a rapid collapse of the ice margin in the lowlands during about 250 yr and, during the Younger Dryas, several outburst floods from glacial Lake Algonquin into the Champlain Sea through the middle Ottawa Valley.

Occhietti, S.; Anderson, T. W.; Karrow, P. F.; Lewis, M. C.; Mott, R. J.; Parent, M.; Richard, P. J.; Rodrigues, C. G.; Stea, R.

2005-12-01

85

North East Coast False Color Time Lapse from SeaWiFS (Gulf of St. Lawrence to Cape Cod)  

NSDL National Science Digital Library

Transitions between relatively cloud free scenes of the northeast coast from the Gulf of St. Lawrence to Cape Cod, using true color land and clouds with false color-chlorophyll water images, all from SeaWiFS

Allen, Jesse; Feldman, Gene

1998-09-09

86

Distribution of submerged aquatic vegetation in the St. Louis River estuary: Maps and models  

EPA Science Inventory

In late summer of 2011 and 2012 we used echo-sounding gear to map the distribution of submerged aquatic vegetation (SAV) in the St. Louis River Estuary (SLRE). From these data we produced maps of SAV distribution and we created logistic models to predict the probability of occurr...

87

A Regional Comparison of the Long-Term Carbon Dynamics Within Maritime Peat Bogs Along the St. Lawrence North Shore, Northeastern Canada  

NASA Astrophysics Data System (ADS)

We have reconstructed the long-term carbon (C) dynamics within maritime bogs from two ecoclimatic regions between the Estuary (Baie-Comeau) and the Gulf of St. Lawrence (Havre-St.-Pierre) in northeastern Canada. The long-term average rates of C accumulation (LORCA) were calculated for eight peatlands. We also compared the Holocene variations in C sequestration between the peatlands to evaluate the influence of climate variability on their long-term C balance. The accumulation/decay processes were linked with changes in vegetation and water table depth. Overall, the LORCA decrease with the age of the peat deposits likely due to constant anoxic decay but they are significantly lower in Havre-St.-Pierre (16-46 g C m-2 yr-1) than in Baie-Comeau (53-68 g C m-2 yr-1). The regional differences in the LORCA reveal a pervasive climatic control on the long-term C balance. Our data suggest that the C accumulation in these bogs was driven by complex interactions between the peat accumulation/decay processes and the climate-mediated water table fluctuations. The higher C accumulation rates in the bogs of Baie-Comeau were promoted by stable ecohydrological conditions whereas the C balance in the bogs of Havre-St.-Pierre was more easily disrupted by past hydroclimatic changes especially during the Neoglacial cooling.

Magnan, G.; Garneau, M.

2013-12-01

88

Estuaries  

NSDL National Science Digital Library

Estuaries are bodies of water and their surrounding coastal wetlands typically found where rivers meet the sea. Estuaries harbor unique plant and animal communities because their waters are brackish--a mixture of fresh water draining from the land and salty seawater.Estuaries are some of the most productive ecosystems in the world. Many animal species rely on estuaries for food, places to breed, and migration stopovers. Human communities also rely on estuaries for food, recreation, jobs, and coastal protection.Of the 32 largest cities in the world, 22 are located on estuaries (e.g., New Orleans, London, etc). Not surprisingly, human activities have led to the decline in the health of estuaries, making them one of the most threatened ecosystems on the Earth. NOAA's National Estuarine Research Reserve System in partnership with coastal states monitors the health of estuaries and helps communities manage their coastal resources.

Educator, Laura K.; National Science Teachers Association (NSTA); Review, Steve W.

2005-04-01

89

Predation on Ruffe by Native Fishes of the St. Louis River Estuary, Lake Superior, 1989–1991  

Microsoft Academic Search

The ruffe Gymnocephalus cernuus, an exotic Eurasian percid, recently became es- tablished in the St. Louis River estuary. Lake Superior, after accidental introduction. Management actions (catch regulations and stockings) were enacted in 1989 to increase the density of top-level predators in the estuary, and thus to increase predation on ruffe. We conducted a field and laboratory study to determine if.

DEREK H. OGLE; JAMES H. SELGEBY; JACQUELINE E. SAVING; RAYMOND M. NEWMAN; MARY G. HENRY

1996-01-01

90

The influence of wind and ice on spring walrus hunting success on St. Lawrence Island, Alaska  

NASA Astrophysics Data System (ADS)

St. Lawrence Island Yupik hunters on St. Lawrence Island, Alaska, take hundreds of Pacific walrus (Odobenus rosmarus divergens) each year. The harvest and associated effort (hunting trips taken), however, are variable from year to year and also from day to day, influenced by physical environmental factors among other variables. We used data from 1996 to 2010 to construct generalized additive models (GAMs) to examine several relationships among the variables. Physical factors explained 18% of the variability in harvest in Savoonga and 25% of the variability in effort; the corresponding figures for Gambell were 24% and 32%. Effort alone explained 63% of the harvest in Savoonga and 59% in Gambell. Physical factors played a relatively smaller role in determining hunting efficiency (walrus taken per hunting trip), explaining 15% of the variability in efficiency in Savoonga and 22% in Gambell, suggesting that physical factors play a larger role in determining whether to hunt than in the outcome of the hunt once undertaken. Combining physical factors with effort explained 70% of the harvest variability in Savoonga and 66% in Gambell. Although these results indicate that other factors (e.g. fuel prices, socioeconomic conditions) collectively cause a greater share of variability in harvest and effort than ice and wind, at least as indicated by the measures used as predictors in the GAMs, they also suggest that environmental change is also likely to influence future harvest levels, and that climate models that yield appropriately scaled data on ice and wind around St. Lawrence Island may be of use in determining the magnitude and direction of those influences.

Huntington, Henry P.; Noongwook, George; Bond, Nicholas A.; Benter, Bradley; Snyder, Jonathan A.; Zhang, Jinlun

2013-10-01

91

Genetics and shell morphometrics of assimineids (Mollusca, Caenogastropoda, Truncatelloidea) in the St Lucia Estuary, South Africa  

PubMed Central

Abstract The Assimineidae are a family of amphibious microgastropods that can be mostly found in estuaries and mangroves in South Africa. These snails often occur in great numbers and are ecologically important to the St Lucia Estuary, which forms a crucial part of the iSimangaliso Wetland Park, a UNESCO World Heritage Site. Genetic and shell morphometric analyses were conducted on individuals collected from nine localities distributed from the northern lake regions to the southern lake and the mouth of the St Lucia estuarine lake. Mitochondrial (COI) and nuclear (28S) DNA was used to construct Bayesian Inference, Neighbour-joining, Maximum Parsimony and Maximum Likelihood trees. Principal Component Analysis and Cluster Analysis were performed on standard shell parameter data. Results indicate that two different taxa are present in St Lucia. The taxon comprising individuals from the South Lake and St Lucia Estuary Mouth is identified as Assiminea cf. capensis Bartsch, in accordance with the latest taxonomic consensus. The taxon comprising assimineid individuals from False Bay, North Lake and South Lake, is here tentatively named “Assiminea” aff. capensis (Sowerby). These two taxa exhibit patterns of spatial overlap that appear to vary depending on environmental parameters, particularly salinity. The need to resolve the complex taxonomy of assimineids is highlighted.

Miranda, Nelson A. F.; van Rooyen, Ryan; MacDonald, Angus; Ponder, Winston; Perissinotto, Renzo

2014-01-01

92

Age and growth of lake sturgeon in the upper St. Lawrence River  

USGS Publications Warehouse

The growth of lake sturgeon (Acipenser fulvescens) over time in the upper St. Lawrence River was examined. Growth of lake sturgeon collected during 1993 and 1994 below Robert Moses Dam near Massena, New York, was compared to that reported for the same population almost 25 years earlier. The data suggest that lake sturgeon growth was similar to that reported in the previous study. However, significant differences in the elevations of regression models between males and fish of unknown sex in both data sets suggest possible sexual dimorphism in growth at younger ages.

Johnson, J. H.; Dropkin, D. S.; LaPan, S. R.; McKenna, J. E. , Jr.; Klindt, R. M.

1998-01-01

93

Diet and Feeding Periodicity of Ruffe in the St. Louis River Estuary, Lake Superior  

Microsoft Academic Search

Ruffe Gymnocephalus cernuus, a percid native to Europe and Asia, is established in the Lake Superior drainage and could have negative impacts on native fish through competition for forage and predation on fish eggs. We investigated the diet of ruffes in the 4,654-ha St. Louis River estuary in May-October 1989-1990 and the feeding periodicity of ruffes in two adjacent habitats

DEREK H. OGLE; JAMES H. SELGEBY; RAYMOND M. NEWMAN; MARY G. HENRY

1995-01-01

94

Organochlorine and metal contaminants in traditional foods from St. Lawrence Island, Alaska.  

PubMed

Marine mammals (bowhead whale, walrus, and various seals) constitute the major component of the diet of the Yupik people of St. Lawrence Island, Alaska. St. Lawrence Island residents have higher serum concentrations of polychlorinated biphenyls (PCB) than in the general U.S. population. In order to determine potential sources, traditional food samples were collected from 2004 to 2009 and analyzed for PCBs, three chlorinated pesticides, and seven heavy metals (mercury, copper, zinc, arsenic, selenium, cadmium, and lead). Concentrations of PCB in rendered oils (193-421 ppb) and blubber (73-317 ppb) from all marine mammal samples were at levels that trigger advisories for severely restricted consumption, using U.S. Environmental Protection Agency (EPA) fish consumption advisories. Concentrations of pesticides were lower, but were still elevated. The highest PCB concentrations were found in polar bear (445 ppb) and the lowest in reindeer adipose tissue (2 ppb). Marine mammal and polar bear meat in general have PCB concentrations that were 1-5% of those in rendered oils or adipose tissue. PCB concentrations in organs were higher than meat. Concentrations of metals in oils and meats from all species were relatively low, but increased levels of mercury, cadmium, copper, and zinc were present in some liver and kidney samples. Mercury and arsenic were found in lipid-rich samples, indicating organometals. These results show that the source of the elevated concentrations of these contaminants in the Yupik population is primarily from consumption of marine mammal blubber and rendered oils. PMID:21797772

Welfinger-Smith, Gretchen; Minholz, Judith L; Byrne, Sam; Waghiyi, Vi; Gologergen, Jesse; Kava, Jane; Apatiki, Morgan; Ungott, Eddie; Miller, Pamela K; Arnason, John G; Carpenter, David O

2011-01-01

95

Key environmental human health issues in the Great Lakes and St. Lawrence River basins  

SciTech Connect

In May 1997, an international conference on the effects of the environment on human health in the Great Lakes and St. Lawrence River basins, was held in Montreal, Quebec, Canada. This was the third international conference on this topic sponsored by agencies in the US and Canada. More than 120 platform and poster presentations were given by scientists of different disciplines from the Great lakes region and elsewhere. The presentations represented the most current research findings on the effects of the Great lakes environment on human health. The reports covered environmental contaminant levels of persistent toxic substances (PTSs), routes and pathways of exposure, exposure assessment and human tissue levels of PTSs, human health outcomes, risk communication and assessment, and approaches to scientific collaboration. Reports indicate that levels of contaminants in the Great Lakes and St. Lawrence River basins have generally declined since the 1970s, although certain contaminants have hit a plateau or slightly increased. The findings include elevated body burden levels of contaminants in persons who consume large amounts of some Great Lakes sport fish, developmental deficits and neurologic problems in children of some fish-consuming parents, nervous system dysfunction in adults, and disturbances in reproductive parameters. The findings underscore the need for better public health intervention strategies.

Johnson, B.L.; Hicks, H.E.; Rosa, C.T. De [Dept. of Health and Human Services, Atlanta, GA (United States). Agency for Toxic Substances and Disease Registry] [Dept. of Health and Human Services, Atlanta, GA (United States). Agency for Toxic Substances and Disease Registry

1999-02-01

96

The influence of hydrodynamical processes on sediment transport in the northern Gulf of St Lawrence  

NASA Astrophysics Data System (ADS)

Sediment transport on continental shelves occurs in response to a wide spectrum of hydrodynamical factors each acting at particular temporal scales. We document in this study one such factor, namely the quasi-periodic passage of large-scale meteorological storms over a region at synoptic frequencies (3-20 days). Our case study focuses on the geological evolution of the Natashquan river delta on the northern Gulf of St Lawrence shelf in relation to nearshore currents. Airgun seismic measurements show that the main deltaic lobe has migrated towards the west in a series of transient events. Time-series analysis of current measurements in the region reveals the presence of energetic current fluctuations occurring at synoptic frequencies; predominantly oriented alongshore and towards the west. These fluctuations are coherent with the large-scale winds, and the highest coherence is found around 15 days. Their amplitudes usually exceed 0.4 m s -1, and are thus capable of transporting the sediments found in the region. Tidal currents are less energetic (0.15-0.2 m s -1), are mainly semi-diurnal in nature and their amplitudes are modulated at the Mm periodicity (27.55 days). It is suspected that the Natashquan marine delta progressed towards the west mainly as a result of the transport of sediments by wind-driven current transients that occur during the progression of intense extra-tropical cyclones along the eastern boundary of the Gulf of St Lawrence.

Koutitonsky, V. G.; Long, B.; Lefaivre, D.; Sala, M.

1991-08-01

97

Mapping ecosystem services in the St. Louis River Estuary  

EPA Science Inventory

Sustainable management of ecosystems for the perpetual flow of services beneficial to human communities requires reliable data about from where in the ecosystem services flow. Our objective is to map ecosystem services in the St. Louis River with the overarching U.S. EPA goal of ...

98

Mapping ecosystem services in the St. Louis River estuary (presentation)  

EPA Science Inventory

Management of ecosystems for sustainable provision of services beneficial to human communities requires reliable data about from where in the ecosystem services flow. Our objective is to map ecosystem services in the St. Louis River with the overarching EPA goal of community sust...

99

Three-dimensional modeling of hydrodynamic processes in the St. Lucie Estuary  

NASA Astrophysics Data System (ADS)

Comparing with the studies on large estuarine systems, such as the Chesapeake Bay and the San Francisco Bay, the processes of stratification and transport in small and shallow estuaries are relatively less studied. The St. Lucie Estuary (SLE) is a riverine estuary located on the east coast of south Florida. It is small and shallow, with mean depth of 2.4 m. To study the estuarine processes in the SLE, a hydrodynamic model was developed based on the Environmental Fluid Dynamics Code (EFDC) [Hamrick, J.M., 1992. A three-dimensional environmental fluid dynamics computer code: theoretical and computational aspects. The College of William and Mary, Virginia Institute of Marine Science, Special Report 317, 63 pp.]. The model was calibrated and verified using observational data obtained in 1999 and 2000, respectively. The model variables used for model data-comparisons are water elevation, velocity, temperature, and salinity. The model is then applied to study the hydrodynamic processes in the SLE. It is found that freshwater inflow plays a major role in the stratification and net flushing of the SLE. Stratification generally increases with freshwater inflow. But when the inflow is persistently large for a relatively long period, the estuary can suddenly change from very stratified to well mixed within a few tidal cycles and the stratification collapses. This finding suggests that large and persistent freshwater inflows do not always increase estuarine stratification. Instead, it may cause the stratification to collapse within a short period of time. In addition to gauged tributaries, ungauged lateral inflows can also be important to small and shallow estuaries like the SLE. Although small individually, the ungauged streams and surface runoffs can be a significant portion of the total inflow and affect salinity distribution significantly. Flushing time affects a wide range of hydrodynamic and water quality processes in the estuary. The model results indicate that commonly used formulas, such as the tidal prism formula and the Knudsen formula, may significantly underestimate the flushing time.

Ji, Zhen-Gang; Hu, Guangdou; Shen, Jian; Wan, Yongshan

2007-06-01

100

Genotoxic substances in the St. Lawrence system II: Extracts of fish and macroinvertebrates from the St. Lawrence and Saguenay Rivers, Canada  

SciTech Connect

Aquatic biota frequently accumulate organic contaminants and maintain steady state tissue concentrations that are as much as 10{sup 5} times higher than those in the surrounding water. Although many researchers have studied the accumulation of genotoxic polycyclic aromatic hydrocarbons (PAHs) by aquatic biota, few researchers have used bioassays to investigate the accumulation of genotoxins. In several previous studies the authors used the SOS Chromotest to investigate the genotoxicity of industrial effluent extracts, sediment extracts, and bivalve tissue extracts. In this study they use the SOS Chromotest to investigate the accumulation of organic genotoxins by macroinvertebrates and fish in the St. Lawrence and Saguenay rivers (Quebec, Canada). Tissue concentrations of genotoxins reveal bioconcentration factors in the 10{sup 2} to 10{sup 3} range. Concentrations are partially determined by lipid content (r{sup 2} = 0.22). Lipid-normalized values indicate that genotoxin concentrations in invertebrate tissues are significantly higher than those in fish. Fish values indicate that tissue concentrations are biodiminished, with fish at higher trophic levels having lower tissue burdens of genotoxins. The biodiminution pattern observed corresponds exceptionally well with trophic position assignments made by other authors. More contaminated sites yielded less contaminated specimens. This may be due to the induction of phase 1 and phase 2 detoxification enzymes that is likely to occur at high levels of exposure. Although the results do not support PAHs as the putative genotoxins, the results do indicate that the accumulated genotoxins have similar properties. Tissue to sediment ratios of genotoxins are similar to those observed for genotoxic PAHs, and far lower than those of more persistent organochlorines. Although the authors did not investigate genotoxic effects, they might expect the most dramatic effects in fish that consume contaminated macroinvertebrates.

White, P.A.; Rasmussen, J.B. [McGill Univ., Montreal, Quebec (Canada). Dept. of Biology; Blaise, C. [Environment Canada, Montreal, Quebec (Canada). St. Lawrence Center

1998-02-01

101

January snow accumulation in the St. Lawrence Valley (1961-1990)  

NASA Astrophysics Data System (ADS)

Located in Eastern Canada, the St. Lawrence Valley (between Montreal and Quebec City; ±350 km) is known as one of the snowiest populated valleys in the world. Usually more than 250 cm of snow falls every winter. Snowstorms are frequent, as more than 10 major snowstorms are registered every year [1] interfering greatly with human activities. Numerical analyses (univariate analysis, discriminant analysis and stepwise multiple regression) for the 1961-1990 period on total snow depth for the month of January reveals three winter-regional climates along this valley: A-) the southern part of Montreal; slightly warmer with less snow and less rainfall, B-) the area around Quebec City; colder with more snow and C-) an intermediate corridor in-between those two cities. Two major variables were identified as responsible for explaining these three winter regional climates: maximum temperature and rainfall.

Toupin, Jerry

2009-09-01

102

Age and Variability of Riverine Dissolved Organic Carbon in the St. Lawrence River  

NASA Astrophysics Data System (ADS)

Riverine export of dissolved organic carbon (DOC) to the global ocean represents about 0.25 x 10E15gC/yr.Various studies have shown that this DOC mainly derives from terrestrial organic matter (OM). It is generally considered to be refractory and transported conservatively to the ocean. However, recent work has shown that many rivers carry a high-14C content DOC. Knowledge of the age (residence time) of both labile/refractory components of DOC and of its variability is essential for a robust assessment of riverine DOC role in the global carbon budget. Here, we report chemical and isotopic composition of DOC from the St. Lawrence River, with a focus on 14C ages of labile vs. total fractions, and on the spatial, seasonal to interannual variability of DOC-export. Alkaline CuO oxidation was used to collect refractory fractions of DOC and to identify sources and degradation stages of terrestrial organic matter. Our results indicate some variability in total DOC from year to year, but more notably, in temporal and spatial variability of 14C-activities of refractory components, which represent approximately 5 to 15% of total DOC and yielded 14C-activities ranging between 75 and 96% of modern carbon (pMC). From these values, 14C-activities of labile compound were estimated. They range from 100 to 111pMC. It is concluded that labile DOC compounds have a very young age/short residence time. This residence time is much shorter than the one estimated for water in the Great Lakes/St. Lawrence River system, thus suggesting prominent terrestrial sources for this reactive organic carbon. Although representing lesser overall fluxes, refractory material display ages pointing towards their previous significant residence time in soils.

Moingt, M.; Hillaire-Marcel, C.; Dever, L.; Gelinas, Y.; Barbecot, F.

2007-05-01

103

POTASSIC MAGMATISM ON ST. LAWRENCE ISLAND, ALASKA, AND CAPE DEZHNEV, NORTHEAST RUSSIA: EVIDENCE FOR EARLY CRETACEOUS SUBDUCTION IN THE BERING STRAIT REGION  

Microsoft Academic Search

Field mapping, geochemical investigations, and geochronology of Cretaceous igneous rocks on St. Lawrence Island were initiated to elucidate the geologic relationships between Russia and Alaska. These data suggest that the Cretaceous magmatic history of St. Lawrence Island can be divided into an early phase of potassic plutonism around 113 Ma and a subsequent phase of larger-volume subalkaline magmatism between 110

Jeffrey M. Amato; Elizabeth L. Miller; Andrew T. Calvert; Jaime Toro; James E. Wright

104

EARLY MARINE LIFE OF ATIANTIC SALMON, SALMO SALAR, POSTSMOLTS IN THE NORmERN GULF OF ST. LAWRENCE  

Microsoft Academic Search

Postsmolts of Atlantic salmon. Salmo salar. having spent some 2-4 months in the marine environ· ment were collected in the nearshore zone of the northern Gulf of St. Lawrence. From a back­ calculated smolt length of 135 mm they had increased in length to 265 mm (212 gl on 1 September, and 306 mm (320 gl on 30 September. The

J.-D. DUTIL; M. COUTUI

105

Simulation of Ice-Cover Growth and Decay in One Dimension on the Upper St. Lawrence River.  

National Technical Information Service (NTIS)

A series of models are presented for simulating the growth and decay of channel ice in one dimension on the upper St. Lawrence River. A general description of ice growth and decay is given for the reach of the river between the Moses-Saunders Power Dam at...

G. M. Greene

1981-01-01

106

Quagga mussels ( Dreissena bugensis) as biomonitors of metal contamination: A case study in the upper St. Lawrence River  

Microsoft Academic Search

In this study, the utility of quagga mussels (Dreissena bugensis) as biomonitors was investigated by measuring total concentrations of three trace metals, cadmium, copper, and zinc, in soft tissues. Quagga mussels were sampled from five sites along the upper St. Lawrence River, including one industrially influenced site, from 1999 through 2007. Mussels were collected from near-shore areas, divided into 5

Carolyn Johns

2011-01-01

107

Development of a 3-D geological model towards natural hazards mitigation, St. Lawrence River Valley, Eastern Canada  

Microsoft Academic Search

As part of the Canadian Government's main goals to ensure safe and strong communities for its citizens, the Geological Survey of Canada has recently undertaken the development of a 3-D geological model and a seamless surficial geology map of the St. Lawrence River valley in Eastern Canada. This paper summarizes the initial phase of this project, which consists of gathering,

RÉJEAN COUTURE; DOMINIQUE GAUVREAU; J. ROBERT BÉLANGER

108

Spatial Distribution of Total Cadmium, Copper, and Zinc in the Zebra Mussel ( Dreissena polymorpha) Along the Upper St. Lawrence River  

Microsoft Academic Search

The zebra mussel (Dreissena polymorpha) was utilized to assess the spatial distribution of three trace metals, cadmium, copper, and zinc, in the upper St. Lawrence River and to test the hypothesis that outflow from Lake Ontario influenced levels of these metals in near-shore biota. Zebra mussels, collected from twelve sites along the southern shore, were analyzed for total cadmium, copper,

Carolyn Johns

2001-01-01

109

Ground-water quality and data on wells and springs in Pennsylvania; Volume I, Ohio and St. Lawrence River basins  

USGS Publications Warehouse

Volume I of the Groundwater Quality and Data on Wells and Springs in Pennsylvania presents groundwater quality and physical data on about 1,200 well and spring sites in the Ohio and St. Lawrence River basins. Locations are shown on site-location maps derived from the hydrologic unit map. Codes showing the geologic age and aquifer are provided. (USGS)

Koester, Harry E.; Miller, Denise R.

1980-01-01

110

Exotic species replacement: shifting dominance of dreissenid mussels in the Soulanges Canal, upper St. Lawrence River, Canada  

Microsoft Academic Search

During the early 1990s, 2 Eurasian macrofouling mollusks, the zebra mussel Dreissena polymorpha and the quagga mussel D. bugensis ,c olonized the freshwater section of the St. Lawrence River and decimated native mussel populations through competitive interference. For several years, zebra mussels dominated molluscan biomass in the river; however, quagga mussels have increased in abundance and are apparently displacing zebra

Anthony Ricciardi; Fred G. Whoriskey

2004-01-01

111

Marine boating habits and the potential for spread of invasive species in the Gulf of St. Lawrence  

Microsoft Academic Search

The potential for boating to disperse the clubbed tunicate Styela clava Herdman, 1881 and green crab Carcinus maenas (Linnaeus, 1758) in the southern Gulf of St. Lawrence was investigated using interviews with recreational and commercial boaters in eastern Prince Edward Island (PEI). Boaters were asked how long their boat had been at the present location; the primary use of the

Emily Darbyson; Andrea Locke; John Mark Hanson; J. H. Martin Willison

2009-01-01

112

Distribution and fluxes of metals in the St. Lawrence River from the outflow of Lake Ontario to Québec City  

Microsoft Academic Search

Six anchor stations in the St. Lawrence River from the outflow of Lake Ontario to Quebec City, were occupied for ca. 24 hours in June 1987 during low flow conditions. Samples of water and suspended particulate matter were separated by continuous-flow centrifugation, and were collected every two hours.

Ken R. Lum; K. L. E. Kaiser; C. Jaskot

1991-01-01

113

Isotopic monitoring (2H, 18O) of the St. Lawrence and Ottawa rivers between 1997 and 2003- Links with interannual climatic variability and hydrological processes in their catchment basins  

NASA Astrophysics Data System (ADS)

This study based on a water isotope (18O and 2H) monitoring of the St. Lawrence and Ottawa rivers (Canada) is a contribution to the international IAEA project: Isotopes tracing of hydrologic processes in large river basins [Gibson et al., 2002. EOS 83: 613 et p.]. Sampling of the St. Lawrence and Ottawa river waters started in 1997, on a biweekly to weekly basis. Monitoring stations are located at Montreal (i.e., at the outlet of the Great Lakes), Quebec City (the estuary of the St. Lawrence) and at the Carillon hydroelectric dam, near the outlet of a major tributary, the Ottawa River into the St. Lawrence itself. The goal of the study was to examine the seasonal and interannual variability of isotopic signatures of the St. Lawrence and Ottawa rivers, in relation notably with interannual climatic variations, and seasonal hydrologic processes in the watershed (summer evaporation, snowmelt, transit time of precipitation signals into runoff). Waters sampled at the three stations depict distinct isotopic compositions. At Montreal, relatively stable isotopic composition are observed with a mean weighted annual value of -54 % for 2H and -7.1 % for 18O. The Ottawa River water at Carillon also displays stable isotopic compositions but much lighter values (weighted mean annual values: -80 % for 2H and -10.8 % for 18O). Finally, isotopic compositions at Quebec City are intermediate between those of Montreal and Carillon, but show a much larger variability. They reflect mixing between the heavy isotope enriched Great Lakes water, the lighter water from the Ottawa River, and highly variable inputs from smaller tributaries (from the Laurentides and Appalachian mountains). The mean weighted isotopic compositions at Quebec City are -65 % and -8.6 %, respectively for 2H and 18O). Evaporative enrichment, in particular during low water level episodes, seem to be more important in the Ottawa River catchment than in the Great Lakes basin, based on a comparison of isotopic clusters at Montreal and Carillon (figure 1). Relatively strongly correlated relationships are observed between isotopic compositions at the estuary of the St. Lawrence River (Quebec) and hydrologic variables such as water discharge. The best fit follows the equation : 2HQUEBEC = -1.9E-03 * QQUEBEC - 41.9, R2= 0.59. Such a relationship leads us to conclude that some properties of the regional hydrology can be relatively well described by stable isotope systematics. In contradiction, air temperatures are not well correlated with isotopic signatures partly because of lag times between them in relation to transit time of precipitation signal into runoff. A comparison of isotopic values in precipitation to those of runoff gives an estimate of the mean transfer time of water from the catchment to the river estuary. For summer heavy isotope enriched, but scarcer precipitation, a transit time of approximately 3 months is observed, whereas in winter, it can be as long as 4 to 5 months due to the residence time of winter precipitation in the snowcover. The assessment of the interannual variability of the St. Lawrence River isotopic system will require a better estimate of the isotopic inprint from small tributaries (that drain isotopically buffered ground waters, particularly in winter). Data are presently at processing stage.

Myre, A.; Hillaire-Marcel, C.

2004-05-01

114

Linking Species Traits to the Abiotic Template of Flowing Waters: Contrasting Eco physiologies Underlie Displacement of Zebra Mussels by Quagga Mussels in a Large River-Estuary  

Microsoft Academic Search

The St. Lawrence River-Estuary was the gateway of entry for dreissenids to North America and holds some of the oldest populations. The St. Lawrence also has four distinct physical-chemical water masses (a regional scale abiotic template) that both species inhabit. Despite their ecological similarities, quagga mussels are supplanting zebra mussels in much of their shared range. In order to try

A. F. Casper

2005-01-01

115

Mo & Fe Influences on Nitrate Assimilation in Lake Ontario and the St Lawrence River  

NASA Astrophysics Data System (ADS)

Lake Ontario has undergone a steady increase in nitrate since the early 1970s, a phenomenon also occurring in other large lakes. Possible causes of this increase include rising urban and agricultural runoff, atmospheric deposition, less demand for N due to effective point source P control, and trace metal-N co-limitation as observed in Lake Erie. Despite the abundance of nitrate in Lake Ontario, heterocystous cyanobacteria have been detected here setting up the paradoxical situation wherein some cyanobacteria are investing in the more costly diazotrophy whilst surrounded by a form of N that requires less energy and metal quota to assimilate. Mo and Fe are involved in reductive nitrate assimilation making it possible that reductive nitrate assimilation in Lake Ontario is limited in phytoplankton by low trace metal bioavailability. To test this hypothesis, 1-d enrcihment experiments were conducted using trace metal clean techniques in June 2013 at two coastal sites in Lake Ontario, and 4-d enrichment experiments were conducted in July 2013 on main channel waters of the St. Lawrence River, the outflow of Lake Ontario. Water was sampled from the metalimnion of Lake Ontario and from surface water of the main channel of the river. Water was enriched with the the following treatments in triplicate: control, 100 nM KH2PO4, 50 nM FeCl3, 50 nM Na2MoO4, and a mix of P, Fe & Mo. Experiments in the river showed significant effects due to P (increase in Chl-a, NO3 and SiO2 drawdown, changes in phytoplankton community, increase in photosynthetic efficiency [Fv/Fm]) but less impact of trace metals relative to control, presumably due to greater ambient trace metal bioavailability. As measured using FluoroProbe, the phytoplankton community changed very little (over 1 d) in lake waters; there was no significant change in total chl-a. However, as in the river, Fv/Fm revealed significant metal and P effects with the P, Fe & Mo mix being significantly greater than control (Fig. 1; we will present data relating to the response of PON and POC pools to the enrichment experiments). The results suggest that P was limiting phytoplankton growth and that Mo and Fe were more co-limiting in the lake than in the river. This information builds on prior work demonstrating Fe/N co-limitation and is the first study to investigate the role of Mo in the N cycle in the Laurentian Great Lakes. Figure 1. Photosynthetic efficiency in experimental treatments measured using fast repetition rate fluorimetry after 1 d (Lake Ontario) and 4 d (St. Lawrence River); * = P < 0.05.

Twiss, M. R.; Salk, K.; Avolio, L. N.; Chappaz, A.; Ostrom, N. E.

2013-12-01

116

Estuaries  

NSDL National Science Digital Library

An estuary is a body of water that is created when freshwater from rivers and streams flows into the saltwater of an ocean. To understand this mixing of fresh and salt water, learners go through several activities: 1) in Salt and Water, learners dissolve salt crystals in water to observe their effects on water; 2) in Making a Salt Wedge, learners make a model of a salt wedge estuary, which occurs in nature when the mouth of a river flows directly into seawater; 3) in Plant Dehydration learners observe the effects of salinity (salt content in the water) on live plants. Includes a wrap-up guide for group discussions.

Jersey, New; Center, Liberty S.; Coalition, New J.

2006-01-01

117

Lake sturgeon spawning on artificial habitat in the St Lawrence River  

USGS Publications Warehouse

In 1996, lake sturgeon (Acipenser fulvescens) spawning was documented for the third consecutive year on an artificially placed gravel bed in the St Lawrence River. Two distinct spawning periods were observed in 1996. Spawning initially commenced on 17 June, when water temperature reached 15??C. A second spawning event was documented from 28 June to 1 July (16??C). Sturgeon egg densities were monitored in three transects on egg trays, on the gravel surface, and within interstitial spaces in the gravel. Counts of developing eggs in the gravel bed during both spawning periods were used to estimate a total of 275000 eggs on the study area (0.075 ha). Average egg density was highest in the transect with the highest water velocities. Lake sturgeon fry were first observed in the gravel on 24 June (15.5??C), and first emergence from the gravel was documented on 28 June. Hatching following the second spawning event commenced on 3 July. Based on assessment of average embryo viability (61.6%) and egg-to-emergent fry survival (17.6%) an estimate of about 171000 sturgeon eggs hatched, producing over 49000 emergent fry. Current velocity, substrate particle size, depth of substrate, and maintenance of sediment-free interstitial spaces are important considerations in planning future spawning habitat enhancement projects. ?? Journal compilation 2006 Blackwell Verlag, Berlin.

Johnson, J. H.; Lapan, S. R.; Klindt, R. M.; Schiavone, A.

2006-01-01

118

Late Quaternary history of the southwestern St. Lawrence Lowlands and adjacent Adirondack Highlands  

SciTech Connect

The reconstruction of Late Wisconsinan ice retreat, proglacial lakes, and Champlain Sea history from the northwest Adirondack slope and adjacent St. Lawrence Lowlands is critical to the synthesis of a regional picture of deglacial events in the eastern Great Lakes region. Unfortunately, these same areas are well known for their limited exposures, landforms covered by thick forest, large tracts of land inaccessible to detailed field mapping, and the overall paucity of glacial materials preserved on upland surfaces. Despite these limitations, a model which utilizes multiple and field-truthed evidence has been used to designate areas where ice border deposits indicate a substantial recessional position. It employs the following criteria in this analysis: sedimentology and morphostratigraphy of morainal landform segments and related sediments; orientation and continuity of ice border drainage channels; and the relationship of ice borders and drainage systems to well documented local and regional water bodies which accompanied ice retreat. The results of this approach have provided a unique regional picture of deglaciation. Despite the inherent limitations of working in upland areas to reconstruct glacial events, detailed morphostratigraphic correlations based on multiple lines of evidence can yield important information. The positions of five former ice borders have been reconstructed from the available data. These ice margins correspond closely with those documented previously by others adjoining areas. This type of study, utilizing multiple and field-truthed lines of evidence, constitutes a tangible step towards understanding the nature and history of ice retreat along this portion of the Laurentide Ice Sheet.

Pair, D.L. (Univ. of Dayton, OH (United States). Dept. of Geology)

1993-03-01

119

Spatial and temporal variation in abundance of Diplostomum spp. in walleye ( Stizostedion vitreum ) and white suckers ( Catostomus commersoni ) from the St. Lawrence River  

Microsoft Academic Search

Abundances of eye flukes (Diplostomum spp.) were compared between walleye (Stizostedion vitreum) and white suckers (Catostomus commersoni ) collected in late summer 1997 from Lake St. Louis and Lake St. Pierre, two expansions of the St. Lawrence River in Quebec, Canada. The white sucker, a benthic consumer, was more heavily in- fected than the walleye, a pelagic piscivore, in both

David J. Marcogliese; Pierre Dumont; Andrée D. Gendron; Yves Mailhot; Emmanuelle Bergeron; J. Daniel McLaughlin

2001-01-01

120

A survey of the St. Louis River estuary with emphasis on non-indigenous species and habitat structure  

EPA Science Inventory

As part of a larger study to develop a monitoring network for aquatic non-indigenous species (NIS), a comprehensive multi-gear survey of larval fish and macroinvertebrates in the St. Louis River estuary was conducted during summer 2012. A total of 139 larval fish samples and 118...

121

Shoreline Classification of the St. Louis River Estuary using Geographic Information Systems and Standard Landuse/Landcover Data Sets  

EPA Science Inventory

The St. Louis River Estuary (SLRE) shoreline is ~300 km in length and borders MN and WI from the MN highway 23 downstream to Lake Superior. The shoreline is a complex and diverse mixture of many features from industrial docks and slips in the lower SLRE to complex wetlands and na...

122

Fish Community Changes in the St. Louis River Estuary, Lake Superior, 1989–1996: Is It Ruffe or Population Dynamics?  

Microsoft Academic Search

Ruffe (Gymnocephalus cernuus) have been implicated in density declines of native species through egg predation and competition for food in some European waters where they were introduced. Density estimates for ruffe and principal native fishes in the St. Louis River estuary (western Lake Superior) were developed for 1989 to 1996 to measure changes in the fish community in response to

Charles R. Bronte; Lori M. Evrard; William P. Brown; Kathleen R. Mayo; Andrew J. Edwards

1998-01-01

123

Fossil brines preserved in the St-Lawrence Lowlands, Québec, Canada as revealed by their chemistry and noble gas isotopes  

Microsoft Academic Search

Brines in Cambrian sandstones and Ordovician dolostones of the St-Lawrence Lowlands at Bécancour, Québec, Canada were sampled for analysis of all stable noble gases in order to trace their origin and migration path, in addition to quantifying their residence time. Major ion chemistry indicates that the brines are of Na–Ca–Cl type, possibly derived from halite dissolution. 87Sr\\/86Sr ratios and Ca

Daniele L. Pinti; Catherine Béland-Otis; Alain Tremblay; Maria Clara Castro; Chris M. Hall; Jean-Sébastien Marcil; Jean-Yves Lavoie; Raynald Lapointe

2011-01-01

124

Historical changes in herbaceous wetland distribution induced by hydrological conditions in Lake Saint-Pierre (St. Lawrence River, Quebec, Canada)  

Microsoft Academic Search

Historical changes (1961–2002) in the distribution of herbaceous wetland plant associations were inferred from the hydrological regime of Lake Saint-Pierre, a 312 km2 broadening of the St. Lawrence River (Quebec, Canada), to assess the cumulative effects of human interventions and climatic variability. Relative abundance index (height × percent cover) of wetland plants in 630 field quadrats sampled at 13 sites (1999–2002)

Christiane Hudon; Pierre Gagnon; Jean-Pierre Amyot; Guy Létourneau; Martin Jean; Céline Plante; Daniel Rioux; Martin Deschênes

2005-01-01

125

Hyperactivity and impulsiveness in rats fed diets supplemented with either Aroclor 1248 or PCB-contaminated St. Lawrence river fish  

Microsoft Academic Search

We examined whether exposure to polychlorinated biphenyls (PCBs) around puberty would produce hyperactivity and impulsiveness in adult Sprague–Dawley rats. Randomly assigned groups consumed food containing environmental concentrations of Aroclor 1248, PCB-contaminated St. Lawrence River carp, or corn oil (control). All received operant training to a final multiple (mult) 120-s, fixed interval (FI), 5-min extinction (EXT) schedule. Pressing rates of both

David F Berger; John P Lombardo; Peter M Jeffers; Anne E Hunt; Brian Bush; Ann Casey; Fred Quimby

2001-01-01

126

Dioxin-Like Compounds in Fishing People from the Lower North Shore of the St. Lawrence River, Québec, Canada  

Microsoft Academic Search

In this study, investigators assessed exposure to dioxin-like compounds in a fishing population that inhabits small coastal communities along the Lower North Shore of the St. Lawrence River, Quebec. This population relies heavily on wildlife foods for sustenance. Investigators analyzed chemically the most popular marine foods (i.e., fish, crustaceans, sea mammals, and sea-bird eggs), and they also obtained 25 human

John J. Ryan; Eric Dewailly; Andy Gilman; Claire Laliberté; Pierre Ayotte; Jean Rodrigue

1997-01-01

127

Distribution, abundance, and feeding of a disjunct population of lady crab in the southern Gulf of St. Lawrence, Canada  

Microsoft Academic Search

The lady crab (Ovalipes ocellatus) is one of the most common native species of swimming crab (Portunidae) of the Atlantic Coast of North America but most populations\\u000a occur south of Cape Cod, Massachusetts. There is a disjunct population in Northumberland Strait (southern Gulf of St Lawrence),\\u000a which was the focus of this study. Adult lady crabs were collected by trawling

Jennifer L. Voutier; John Mark Hanson

2008-01-01

128

Ground-Water Quality in the St. Lawrence River Basin, New York, 2005-06  

USGS Publications Warehouse

The Federal Clean Water Act requires that States monitor and report on the quality of ground water and surface water. To satisfy part of these requirements, the U.S. Geological Survey and New York State Department of Environmental Conservation have developed a program in which ground-water quality is assessed in 2 to 3 of New York State's 14 major river basins each year. To characterize the quality of ground water in the St. Lawrence River Basin in northern New York, water samples were collected from 14 domestic and 11 production wells between August 2005 and January 2006. Eight of the wells were finished in sand and gravel and 17 wells were finished in bedrock. Ground-water samples were collected and processed using standard U.S. Geological Survey procedures and were analyzed for 229 constituents and physical properties, including inorganic constituents, nutrients, trace elements, radon-222, pesticides and pesticide degradates, volatile organic compounds, and bacteria. Sixty-six constituents were detected above laboratory reporting levels. Concentrations of most compounds at most sites were within drinking water standards established by the U.S. Environmental Protection Agency and New York State Department of Health, but a few compounds exceeded drinking water standards at some sites. Water in the basin is generally hard to very hard (hardness equal to 121 mg/L as CaCO3 or greater); hardness and alkalinity were generally higher in the St. Lawrence Valley than in the Adirondack Mountains. The cation with the highest median concentration was calcium; the anion with the highest median concentration was bicarbonate. The concentration of chloride in one sample exceeded the 250 milligrams per liter U.S. Environmental Protection Agency Secondary Drinking Water Standard; the concentration of sulfate in one sample also exceeded the 250 milligrams per liter U.S. Environmental Protection Agency Secondary Drinking Water Standard. Nitrate was the predominant nutrient detected but no sample exceeded the 10 mg/L U.S. Environmental Protection Agency Maximum Contaminant Level. The trace elements detected with the highest median concentrations were strontium, barium, and iron. Concentration of trace elements in several samples exceeded U.S. Environmental Protection Agency Secondary Drinking Water Standards, including aluminum (50 micrograms per liter, 4 samples), iron (300 micrograms per liter, 5 samples), and manganese (50 micrograms per liter, 4 samples). The concentration of uranium in one sample from a domestic well finished in crystalline bedrock was three times the U.S. Environmental Protection Agency Maximum Contaminant Level of 30 micrograms per liter. The median concentration of radon-222 was 600 picoCuries per liter, but concentrations as high as 18,800 picoCuries per liter were detected; two wells with high radon concentrations also had high uranium concentrations. Radon-222 is not currently regulated, but the U.S. Environmental Protection Agency has proposed a Maximum Contaminant Level of 300 picoCuries per liter along with an Alternative Maximum Contaminant Level of 4,000 picoCuries per liter, to be in effect in states that have programs to address radon in indoor air. Concentrations of radon-222 exceeded the proposed Maximum Contaminant Level in 60 percent of samples and exceeded the proposed Alternative Maximum Contaminant Level in 8 percent of samples. Six pesticides and pesticide degradates were detected; all were amide or triazine herbicides or degradates. Five volatile organic compounds were detected, including disinfection byproducts such as trichloromethane and gasoline components or additives such as methyl tert-butyl ether. No pesticides, pesticide degradates, or volatile organic compounds were detected above established limits. Coliform bacteria, including Escherichia coli, were detected in three wells finished in carbonate bedrock.

Nystrom, Elizabeth A.

2007-01-01

129

Trace metals in the Columbia River Estuary following the 18 May 1980 eruption of Mount St. Helens  

SciTech Connect

Dissolved and suspended concentrations of cadmium, copper, iron, manganese, nickel, lead, and zinc were measured in the Columbia River Estuary following the 18 May 1980 eruption of Mount St. Helens. Soluble concentrations of these trace elements were not substantially elevated by the influx of volcanic ash and mud into the estuary during this period, except for somewhat higher than usual concentrations of manganese and copper. A laboratory experiment indicates that manganese leached from volcanic debris in fresh water and in the transition from fresh to slightly saline water probably caused the elevated Mn leaching from the material into fresh water.

Riedel, G.F.; Wilson, S.L.; Holton, R.L.

1984-10-01

130

Recent sediments of the St. Marks River coast, northwest Florida, a low-energy, sediment-starved estuary  

SciTech Connect

The St. Marks river of northwest Florida drains parts of the central panhandle of northwestern Florida, and a small area in southwestern Georgia. It traverses nearly 56.3 kilometers through a watershed of 1,711 square kilometers. The slow-moving river carries little sediment and terminates in Apalachee Bay, a low-energy embayment in the northeasternmost Gulf of Mexico. The coastal region is characterized by mudflats, seagrass beds, and an absence of sandy beaches and barrier islands. Clastic sediments of the coast and shelf rest on a shallow-dipping carbonate platform. The upper surface of the platform is locally karstic. As a result, like other rivers in this region of northwest Florida, the St. Marks watershed is marked by sinkholes and disappearing streams. The fact that the river travels underground through part of its lower watershed serves to trap or sieve some of its clastic load. In the estuary, the undulating karst topography causes the estuarine sediments to vary in thickness from 0 to 4+ meters. The concave shape of the coastline and its orientation with respect to prevailing winds result in low average wave energy. Sedimentation is therefore controlled by riverine and tidal forces. The relatively low energy conditions result in good preservation of the sedimentary record in the St. Marks estuary. A suite of sediment cores has been collected in the lower river, estuary and adjacent Gulf of Mexico. Lead-210 dating results indicate a slow average sedimentation rate ([approximately] 1mm/yr). Investigation of sedimentation rates and sediment characteristics over time in the St. Marks estuary indicate that sedimentologic conditions in this low-energy environment have been relatively stable during the recent geologic history of the estuary.

Highly, A.B. (Florida State Univ., Tallahassee (United States). Dept. of Geology Florida Geological Survey, Tallahassee, FL (United States)); Donoghue, J.F. (Florida State Univ., Tallahassee, FL (United States). Dept. of Geology); Garrett, C.; Hoenstine, R.W.; Hertler, H. (Florida Geological Survey, Tallahassee, FL (United States))

1994-03-01

131

Index of surface-water records, part 4, St. Lawrence River Basin, to September 30, 1950  

USGS Publications Warehouse

The index lists the stream-flow and reservoir stations in the St. Lawrence River Basin for which records have been or are to be published for periods prior to September 30, 1950. The stations are listed in downstream order. Tributary streams are indicated by indention. Station names are given in their most recently published forms. Parentheses around part of a station name indicate that the inclosed word or words were used in an earlier published name or the station or in a name under which records were published by same agency other than the Geological Survey. The drainage areas, in square miles, are the latest figures published or otherwise available at this time. Drainage areas that were obviously inconsistent with other drainage areas on the same stream have been omitted. Some drainage areas not published by the Geological Survey are listed with an appropriate footnote stating the published source or the figure or drainage area. Under "period of record" breaks of less than a 12-month period are not shown. A dash not followed immediately by a closing date shows that the station was in operation on September 30, 1950. The years given are calendar years. Periods of records published by agencies other than the Geological Survey are listed in parentheses only when they contain more detailed information or are for periods not reported in publications to the Geological Survey. Records both of gage height and of discharge are listed for stream-flow stations, and records of gage height and of contents (or of change in contents) are listed for stations on reservoirs. Records of gage heights only and records consisting only of monthly figures either of stream flow or reservoir contents are designated by symbols and footnotes. For early years when daily discharges were not generally published by the Geological Survey, published daily gage heights and a published rating table are considered to be equivalent to daily discharges. An alphabetical index of streams. canals. and reservoirs is given on pages 12 to 14.

U.S. Geological Survey

1951-01-01

132

Crustal Structure Beneath the Gulf of ST. Lawrence, Atlantic Canada, from Ambient Seismic Noise Tomography  

NASA Astrophysics Data System (ADS)

The Gulf of St. Lawrence (GSL), located north of the southwest-northeast trending Appalachian mountain in eastern Canada, is a major sedimentary basin with huge potentials for hydrocarbon accumulation. Important questions about the geometry and evolution of the crustal and basin structure beneath the gulf are yet to be answered. To address these issues, the Geological Survey of Canada (GSC) with support from the Portable Observatories for Lithospheric Analysis and Research Investigating Seismicity (POLARIS) deployed a temporary array of broadband seismic stations in the GSL region between October 2005 and October 2008. Combined with the permanent stations of the Canadian National Seismograph Network (CNSN) in the region, the station density is sufficient for detailed seismic tomography inversion. In this study, we investigate the upper crustal structure beneath the gulf using 3 years of continuous ambient noise waveforms recorded at 25 (POLARIS and CNSN) stations around the GSL. Cross-correlation functions of the vertical component of the ambient noise wavefield for simultaneously recording station pairs (corresponding to inter-station Green's functions) are computed and analyzed using the frequency-time analysis method. Dispersion curves are measured and Rayleigh wave group velocities are subsequently extracted for periods between 2 and 20s, which are periods sensitive to the upper crustal structures. Preliminary results from the dispersion measurements indicate that mean group velocities in the region range from 2.8 to 3.2 km/s across the range of period specified. 2-D group velocity distribution for each period is determined by linearized inversion of the dispersion data. Our tomography results show prominent lateral velocity variation. Low velocity anomalies are observed at shorter periods (up to ~10 s) which correspond to the sedimentary structures at shallow depths (between 5-10 km), whereas the characteristics of upper crustal structures are shown by velocity anomalies at longer periods. Our results show striking similarities with the tomographic images obtained in the previous Canada-wide ambient noise analysis for areas where both studies overlap and are also consistent with results from receiver function and active seismic profiling studies previously done in the region. A detailed inversion of the 3-D shear velocity structure will be conducted to appropriately delineate the thickness and seismic velocity of the composite geologic units.

Kuponiyi, A.; Kao, H.; Cassidy, J. F.; Spence, G.

2013-12-01

133

Paleomagnetic study of Cambrian Potsdam Group sandstones, St. Lawrence Lowlands, Quebec  

NASA Astrophysics Data System (ADS)

We report paleomagnetic results from oriented drill core samples collected at 10 sites (80 samples) from the Covey Hill and 19 sites (96 samples) from the overlying, fossiliferous Chaˆteauguay Formations of the gently dipping Late Cambrian Potsdam Group sandstones exposed in the St. Lawrence Lowlands of Quebec. Stepwise thermal demagnetization analyses ave revealed the presence of two predominant groups of coherent magnetizations C-1 and C-2, after simple correction for bedding tilt. The C-1 group magnetization is a stable direction ( D=332°, I=+18°) with unblocking temperatures ( T UB) between 550 and 650°C, present in the older Covey Hill Formation; this direction is probably a chemical remanence acquired during the Covey Hill diagenesis and carried predominantly by hematite. The C-2 group magnetization ( D=322°, I=+9°) is present at 13 sites of the younger Chaˆteauguay Formation; this is probably carried by magnetite and represents a penecontemporaneous, depositional DRM, characterized by T UB spectra 400-550°C. We believe that C-2 is relatively younger than C-1 based on a combination of arguments such as the presence of opposite polarities, internal consistency, similarity and common occurrence of C-1 and C-2 respectively in the Covey Hill and Chaˆteauguay members. The corresponding paleomagnetic poles C-1 (46°N, 149°E; dp, dm=3°, 5°) and C-2 (37°N, 156°E; dp, dm=2°, 5°) are not significantly different from most of the other Late Cambrian (Dresbachian-Franconian) poles derived from sediments exposed in the southern region (Texas) of the North American craton which are also believed to have been deposited during Croixian Sauk sea transgression similar to the Potsdam sandstones. Although adequate faunal control is lacking (in particular for the Covey Hill Formation), this comparison with the Cratonic poles suggests a Late Cambrian age to the Potsdam poles. The agreement between the results also gives the evidence for internal consistency of cratonic poles at least for Late Cambrian. The incoherent C-3 group remanence ( D=250°, I=-15°) is commonly present at 7 sites in both the formations; this may not correspond to a reliable paleomagnetic signal. The other remanence C-4 ( D=180°, I=+10°) is found only at 3 sites located in the uppermost stratigraphic levels of the Chaˆteauguay Formation; the corresponding paleomagnetic pole (40°N, 107°E) does not differ significantly from the Ordovician and some Late Cambrian poles. The present data are insufficient to resolve a problem in apparent polar wander for Middle and Late Cambrian time posed by the existence of high-latitude poles for some strata of Middle Cambrian age and low-latitude poles for some strata of Late Cambrian age.

Seguin, M. K.; Rao, K. V.; Arnal, P.

1981-11-01

134

Alternative nursery habitat for estuarine associated marine fish during prolonged closure of the St Lucia estuary, South Africa  

NASA Astrophysics Data System (ADS)

The Mfolozi estuary, located on the east coast of South Africa, was historically directly linked to the adjacent St Lucia estuarine system, the largest estuarine system in Africa and a World Heritage Site. The Mfolozi used to be the main feeder system to maintain lake levels in St Lucia, but increased siltation from sugar cane farming in the Mfolozi floodplain led to artificial separation of the two systems in 1950. Reduced freshwater inflow due to drought conditions caused the St Lucia mouth to remain closed from June 2002 to present, coinciding with low lake levels and hypersaline conditions, except for a brief period during 2007 after the St Lucia mouth breached. These conditions led to disruption of larval recruitment into the system and major changes in biotic communities. Due to the importance of the St Lucia - Mfolozi System link, a study was initiated in 2007 on the fish community of the Mfolozi system, which was sampled using seine and gill nets. The 48 species recorded were dominated by juveniles of marine spawners, particularly Leiognathus equula and Valamugil cunnesius and the estuarine spawners Ambassis dussumieri and Ambassis natalensis. Estuarine dependent marine spawning species formed 68% of both the species numbers and CPUE, an indication of the regional importance of the Mfolozi estuary as an alternate refuge for juvenile marine fish during periods when the St Lucia system remained closed. Post-larval recruits of marine spawning species were particularly abundant, but low zoobenthic densities caused a rapid decline in numbers of benthic feeders shortly after their recruitment into the system. The importance of the Mfolozi estuary in maintaining marine brood stocks of estuarine dependent marine fish is discussed with particular reference to estuarine degradation and the ecological integrity of the St Lucia system.

Vivier, Leon; Cyrus, Digby P.

2009-10-01

135

Mercury transport between sediments and the overlying water of the St. Lawrence River area of concern near Cornwall, Ontario  

Microsoft Academic Search

Contaminated sediments in the St. Lawrence River remain a difficult problem despite decreases in emissions. Here, sediment and pore water phases were analyzed for total mercury (THg) and methyl mercury (MeHg) and diffusion from the sediment to the overlying water was 17.5 ± 10.6 SE ng cm?2 yr?1 for THg and 3.8 ± 1.7 SE ng cm?2 yr?1 for MeHg. These fluxes were very small when compared to the particle-bound mercury flux

Tania M. Delongchamp; Jeffrey J. Ridal; David R. S. Lean; Laurier Poissant; Jules M. Blais

2010-01-01

136

The benthic macrofauna of the St. Lucia Estuary during the 2005 drought year  

NASA Astrophysics Data System (ADS)

The St. Lucia Estuary is the largest estuarine system in Africa. The estuary is part of the Greater St. Lucia Wetland Park, which has been declared a World Heritage Site. This ecosystem has been subjected to severe drought conditions over the last four to five years, resulting in its mouth being closed off from the ocean in June 2002 for a period of over four years. The main aim of this study was to document the effects of the prevailing drought on the macrofauna of the system, since the last work on this benthic component had been undertaken over a decade ago, during a normal-to-wet phase. Macrofauna samples together with physico-chemical data were collected at representative sites in the Narrows, and the South and North lakes in February, April, August and October 2005. The drought exerted a strong influence on the system, leading to hypersaline conditions developing in its northern regions (maximum of 126 at Hell's Gate), and to the loss of aquatic habitat. Ordinations and clustering indicated that the macrofauna of the system could generally be separated into three clusters viz. (1) the Narrows and the southern portion of South Lake, (2) the northern half of South Lake, and (3) the North Lake-False Bay complex. Multivariate correlations indicated weak relationships between macrofaunal community structure and physico-chemical parameters. The distinction in macrofaunal assemblages between these clusters was probably caused by these habitats being physically separated at the peak of the drought, with no water flow between them, thereby preventing exchange of planktonic larvae and retarding colonisation of habitats. There was a northward decline in taxonomic richness and diversity of macrofauna in the system, which correlated positively with water depth and negatively with the biomass of microphytobenthos. It is evident that the drought structured macrofauna communities primarily through its effects on water depth and habitat fragmentation. The results of this investigation provide valuable information regarding the effects of droughts on estuarine-lake systems and the possible mechanisms by which they occur.

Pillay, D.; Perissinotto, R.

2008-03-01

137

14C chronology for ice retreat and inception of Champlain Sea in the St. Lawrence Lowlands, Canada  

NASA Astrophysics Data System (ADS)

AMS radiocarbon cross-dating of plant debris and marine shells trapped in a lake basin on Mount St. Hilaire (Québec, Canada) provides a direct assessment of a reservoir effect totaling ca. 1800 14C years during the early stage of Champlain Sea. Pollen-based extrapolation of bottommost ages on terrestrial plant macrofossils in sediments of this lake, and of another lake nearby support an estimate of 11,100 ± 100 14C yr B.P. for marine invasion in the Central St. Lawrence River Lowlands. Results indicate a 400-1000 years younger regional chronology of ice retreat, now congruent with the one inferred from the New England varve chronology. This is a summary of a longer paper to be published in French.

Richard, Pierre J. H.; Occhietti, Serge

2005-05-01

138

Reconnaissance investigation of high-calcium marble in the Beaver Creek area, St. Lawrence County, New York  

USGS Publications Warehouse

Three belts of marble of the Grenville Series were mapped in the Beaver Creek drainage basin, St. Lawrence County, N.Y. One of these, on the west side of Beaver Creek, consists of coarsely crystalline pure calcitic marble that occurs in a zone at least 10 by 0.8 km in extent. Samples of marble show CaCO3 content to be greater than 93 percent, and some samples contain greater than 96 percent, and only small amounts of MgO and Fe203 are present. Marble in two other belts to the east of Beaver Creek are variable in composition, but locally have high content of calcium carbonate material. The marble deposit west of Beaver Creek has a chemical composition favorable for specialized chemical, industrial, and metallurgical uses. Another favorable aspect of the deposit is its proximity to inexpensive water transportation on the St. Lawrence Seaway only 27.5 km away by road, at Ogdensburg, N.Y.

Brown, C. Ervin

1978-01-01

139

Forecasting the Major Influences of Predation and Environment on Cod Recovery in the Northern Gulf of St. Lawrence  

PubMed Central

The northern Gulf of St. Lawrence (NGSL) stock of Atlantic cod (Gadus morhua), historically the second largest cod population in the Western Atlantic, has known a severe collapse during the early 1990 s and is currently considered as endangered by the Committee on the Status of Endangered Wildlife in Canada. As for many fish populations over the world which are currently being heavily exploited or overfished, urgent management actions in the form of recovery plans are needed for restoring this stock to sustainable levels. Stochastic projections based on a statistical population model incorporating predation were conducted over a period of 30 years (2010–2040) to assess the expected outcomes of alternative fishing strategies on the stock recovery under different scenarios of harp seal (Pagophilus groenlandicus) abundance and environmental conditions. This sensitivity study shows that water temperature is key in the rebuilding of the NGSL cod stock. Model projections suggest that maintaining the current management practice under cooler water temperatures is likely to maintain the species in an endangered status. Under current or warmer conditions in the Gulf of St. Lawrence, partial recovery might only be achieved by significant reductions in both fishing and predation pressure. In the medium-term, a management strategy that reduces catch could be favoured over a complete moratorium so as to minimize socio-economic impacts on the industry.

Bousquet, Nicolas; Chassot, Emmanuel; Duplisea, Daniel E.; Hammill, Mike O.

2014-01-01

140

Strike-slip interpretation of basin-bounding faults of the St. Lawrence lowlands basin the Quebec City area, Canada  

SciTech Connect

Traditional structural interpretations of faults identified in the autochthonous, Ordovician platform rocks of the St. Lawrence Lowlands basin of Quebec, Canada, assert that the primary sense of faulting is normal, extensional, and dip-slip in motion. Interpretation of field observations such as the offset of facies boundaries in outcrop, fault surface features, fracture patterns, and fault volume considerations lead directly to difficulties with a mobile crustal bulge model for normal faulting. Newly reprocessed seismic data and well-log correlations support this interpretation and indicate a need for a different model for the deformation of the platform margin. A left-lateral, basement-involved wrench system resolves stratigraphic discordances across fault zones, contradictions in the observed geometry of hanging-wall blocks, problems concerning timing of tectonic events, and the difficulty of using extensional deformation models in a compressional setting. This reinterpretation places the timing of the platform faulting just prior to the arrival of the Taconic thrust sheet. The lateral offset of subsurface and surface depositional facies, fault trace features, well correlations, and seismic expressions document approximately 60 km of left-lateral strike-slip motion in the St. Lawrence Lowlands basin. 30 refs., 14 figs., 1 tab.

Shaw, B.R. (BHP Petroleum (Americas), Houston, TX (United States))

1993-05-01

141

Genetic Divergence among Northern Pike from Spawning Locations in the Upper St. Lawrence River  

Microsoft Academic Search

To assess the ecological consequences associated with the degradation of riparian wetlands that historically provided spawning and rearing habitat for northern pike Esox lucius, annual spawning migrations and genetic structure were used to examine this species' dependence on four specific spawning areas in the Thousand Islands region of the Saint Lawrence River. Tagging and recapture over three consecutive spawning seasons

Aaron Bosworth; John M. Farrell

2006-01-01

142

ASSESSMENT OF WATER QUALITY USING EPIPHYTIC DIATOM ASSEMBLAGES ON CLADOPHORA FROM THE ST. LAWRENCE RIVER (CANADA)  

Microsoft Academic Search

Diatoms epiphytic on Cladophora were examined from 36 sites in the Saint Lawrence River between Salaberry-de-Valleyfield and Ile d'Orleans (Quábec, Canada). A total of 129 diatom taxa were identified from Cladophora in June 1995, and of these, 34 species were present at a relative abundance ? 1% at three or more sites. The four most abundant taxa were Cocconeis pediculus,

Jacqueline M. OConnell; Euan D. Reavie; John P. Smol

1997-01-01

143

Aquatic Vegetation of the St. Louis River Estuary: Initial Analysis of Point-intercept Data Collected in 2010 for Restoration Modeling.  

EPA Science Inventory

A new effort to model aquatic vegetation patterns in the St. Louis River Estuary was initiated in summer of 2010 for the purpose of informing wetland restoration planning in the St. Louis River Area of Concern (AOC) at 40th Avenue West in Duluth. Aquatic vascular plants were doc...

144

Environmental Baseline and Evaluation of the St. Mary's River Dredging: Great Lakes-St. Lawrence Seaway Navigation Season Extension Program.  

National Technical Information Service (NTIS)

The purpose of this study was to gather a quantitative baseline of biological and chemical data from the Middle Neebish Channel in the St. Marys River and from a site in Lake Huron prior to proposed dredging and dredge spoil disposal activities. Field dat...

C. D. McNabb C. R. Liston D. E. Ashton F. E. Koehler W. G. Duffy

1980-01-01

145

Temporal and spatial distribution and production of dissolved gaseous mercury in the Bay St. François wetland, in the St. Lawrence River, Quebec, Canada  

NASA Astrophysics Data System (ADS)

Wetlands are valued for their high biodiversity and for their ecosystem services. However, we still do have a poor understanding of their role in the redox transformation of contaminants such as mercury, particularly in fluvial settings. Seasonal and spatial variations in dissolved gaseous mercury (DGM) distribution and production were studied in the Bay St. François, a wetland in the St. Pierre Lake, a fluvial lake of the St. Lawrence River, in Quebec, Canada. A high spatial resolution for DGM, with samples taken every 10-cm depth, was used in field measurements. Through a series of parallel field and incubation experiments, we assessed the main factors determining Hg(0) transformations as a function of depth, seasons, and presence/absence of macrophyte beds. Besides light penetration in the water column and water temperature, iron and dissolved organic carbon likely stimulated Hg(II) reduction. Inversely, chloride favored Hg(0) oxidation. Macrophytes and associated epiphytes appeared to be important sites of adsorption/absorption of Hg(II) and likely of DGM. It seems however that the effects of macrophytes were restricted to immediately adjacent waters. Near the bottom, under anoxic conditions, the reduction of Hg(II) was highly promoted. In addition, sediments and decomposing macrophytes seemed to release DGM and/or reducible Hg to bottom waters. Overall, differences in DGM between surface and bottom waters tended to be more accentuated than observed differences in DGM between macrophyte beds and sites devoid of plant.

Garcia, Edenise; Laroulandie, Jerôme; Saint-Simon, Xavier R.; Amyot, Marc

2006-06-01

146

Holocene environmental and parasequence development of the St. Jones Estuary, Delaware (USA): Foraminiferal proxies of natural climatic and anthropogenic change  

USGS Publications Warehouse

The benthic foraminiferal record of marshes located along western Delaware Bay (St. Jones Estuary, USA) reflects the response of estuaries to sea-level and paleoclimate change during the Holocene. System tracts are recognized and within them parasequences based on sedimentological and foraminiferal assemblages identification. The parasequences defined by foraminiferal assemblages appear correlative with rapid Holocene climate changes that are of worldwide significance: 6000-5000, 4200-3800, 3500-2500, 1200-1000, and 600??cal years BP. Following postglacial sea-level rise, modern subestuaries and marshes in the region began to develop between 6000 and 4000??years BP, depending on their proximity to the mouth of Delaware Bay and coastal geomorphology. Initial sediments were fluvial in origin, with freshwater marshes established around 4000??years BP. The subsequent sea-level transgression occurred sufficiently slowly that freshwater marshes alternated with salt marshes at the same sites to around 3000??years BP. Locally another two transgressions are identified at 1800 and 1000??years BP respectively. Marine influence increased in the estuaries until 600??years BP (Little Ice Age), when regression occurred. Sea-level began to rise again during the mid-19th Century at the end of the Little Ice Age, when marshes became established. The presence of a sand lens in the upper and middle estuary and the reduction in the number of tests in the top samples in cores from the same area also suggest an anthropogenic influence. The estuary infill resulted in a sharp transgressive sequence, represented by salt marsh foraminiferal assemblages in the upper part of the cores. The increase in marsh foraminifera in both areas suggests an increase in marine influence that might be due to the transgression beginning at the end of the Little Ice Age about 150-180??years ago coupled with anthropogenic straightening of the channel in 1913. ?? 2006 Elsevier B.V. All rights reserved.

Leorri, E.; Martin, R.; McLaughlin, P.

2006-01-01

147

Nitrogen and phosphorus flux rates from sediment in the lower St. Johns River estuary.  

PubMed

Internal cycling of nutrients from the sediment and water column can be an important contribution to the total nutrient load of an aquatic ecosystem. Our objective was to estimate the internal nutrient loading of the Lower St. Johns River (LSJR). Dissolved reactive phosphorus (DRP) and ammonium (NH(4)-N) flux from sediments were measured under aerobic and anaerobic water column conditions using intact cores, to estimate the overall contribution of the sediments to P and N loading to the LSJR. The DRP flux under aerobic water column conditions averaged 0.13 mg m(-2) d(-1), approximately 37 times lower than that under anaerobic conditions (4.77 mg m(-2) d(-1)). The average NH(4)-N released from the anaerobic cores (18.03 mg m(-2) d(-1)) was also significantly greater than in the aerobic cores for all sites and seasons, indicating the strong relationship between nutrient fluxes and oxygen availability in the water column. The mean annual internal DRP load was estimated to be 330 metric tons (Mg) yr(-1), 21% of the total P load to the river, while the mean annual internal load of NH(4)-N was determined to be 2066 Mg yr(-1), 28% of the total N load to the LSJR estuary. As water resource managers reduce external loading to the LSJR the frequency of anaerobic events should decline, thereby reducing nutrient fluxes from the sediment to the water column, reducing the internal loading of DRP and NH(4)-N. Results from this study demonstrate that the internal flux of nutrients from sediments may be a significant portion of the total load and should be accounted for in the total nutrient budget of the river for successful restoration. PMID:15254137

Malecki, Lynette M; White, John R; Reddy, K R

2004-01-01

148

Relationship between water color, water levels, and climate indices in large rivers: Case of the St. Lawrence River (Canada)  

NASA Astrophysics Data System (ADS)

The relationship between the color (measured with Landsat Thematic Mapper and Enhanced Thematic Mapper sensors in bands 1, 2, and 3) of St. Lawrence River (SLR) water and water levels (in SLR and Lake Ontario) was first analyzed, followed by the analysis of the relationship between water levels and four climate indices for the period from 1984 to 2009. Although there is a statistically significant relationship between these first two variables, this link depends on the strength of two factors: the type of color (band) and inflows from tributaries. Bands 1 (blue) and 2 (green) were negatively correlated with water levels. This correlation, however, is spatially influenced by water inflows from tributaries. Band 3 (red) showed no significant correlation with either water level. Over the same period, water levels were negatively correlated with the Atlantic multidecadal oscillation index. Results suggest that the color of waters in the SLR may be used as an indicator to monitor environmental and climate changes in its watershed.

Massicotte, Philippe; Assani, Ali A.; Gratton, Denis; Frenette, Jean-Jacques

2013-04-01

149

Mesozoic fault reactivation along the St. Lawrence Rift System as constrained by (U-Th/He) thermochronology  

NASA Astrophysics Data System (ADS)

The Saint Lawrence Rift System (SLRS) is a half-graben, extending for 1000 km along St. Lawrence River valley. Late Proterozoic-Early Paleozoic faults of the graben form the contact with the metamorphic Grenvillian basement to the northwest and extend under the Paleozoic sedimentary sequences of the St. Lawrence Lowlands to the southeast. The SLRS is the second most seismically active area in Canada, but the causes of this activity remain unclear. Reactivation of the SLRS is believed to have occurred along Late Proterozoic to Early Paleozoic normal faults related to the opening of the Iapetus Ocean. The absence of strata younger than the Ordovician makes difficult to determine when the faults reactivated after the Ordovician. Field relations between the normal faults bordering the SLRS and those produced by the Charlevoix impact crater suggest a reactivation of the rift younger than the Devonian, the estimated age of the impact. Apatite (U-Th)/He thermochronology is an adequate tool to recognize thermal events related to fault movements. A thermochronology study was then started along three transects across the SLRS, from Québec up to Charlevoix. Apatites were extracted and separated from five granitic to charnockitic gneisses and an amphibolite of Grenvillian age. The samples were exposed on hanging wall and footwall of the Montmorency and Saint-Laurent faults at three different locations along the SLRS. For precision and accuracy, each of the six samples was analyzed for radiogenic 4He and U-Th contents at least twice. Apatite grains were isolated by heavy liquids and magnetic separation. For each sample, ten apatite grains were selected under optical microscope and inserted into Pt capsules. Particular care was taken to isolate apatite free of mineral and fluid inclusions. Indeed, SEM investigations showed that some inclusions are U-rich monazite, which is a supplementary source of 4He to be avoided. The 4He content was determined by using a static noble gas mass spectrometer in CRPG-Nancy and duplicates using a quadrupole mass spectrometer at GEOTOP-UQAM. 4He was measured against internal He gas standards and Durango apatite, with the reference U-Th/He age of 31.13 ± 1.01 Ma. U and Th contents were determined at CRPG-Nancy and duplicated at McGill University by ICP-MS. Preliminary results of U-Th/He on St.-Laurent fault yield an age of 137±12 Ma for the hanging wall, at Sault-au-Cochon and 118±10 Ma for a sample from the footwall, at Cap-aux-oies. Previous Apatite Fission Track (AFT) performed for the two locations gave expected older ages at 149±16 Ma and 196±19 Ma for the hanging wall and the footwall, respectively. These preliminary U-Th/He results are consistent with AFT ages of the area (i.e. as expected, U-Th/He ages are younger than AFT ages) but do not yet provide new constraints for the structural evolution of the St. Lawrence rift system. We are determining further U-Th/He ages and these ages will constrain an exhumation model of the region.

Bouvier, L.; Pinti, D. L.; Tremblay, A.; Minarik, W. G.; Roden-Tice, M. K.; Pik, R.

2011-12-01

150

Occurrence of a Syngamus sp. in tundra voles (Microtus oeconomus) collected on St. Lawrence Island, Bering Sea.  

PubMed

A species of syngamid nematode belonging to the genus Syngamus was found in the respiratory tract (terminal trachea to bronchi) of tundra voles (Microtus oeconomus) collected on St. Lawrence Island, Alaska (USA). Its prevalence in June 1989 was greater than 29% (12 of 41 male voles and seven of 24 females) in the village of Savoonga, while no nematodes were found from 41 voles collected in the village of Gambell. Lesions included dilatation of parasitized respiratory ducts and peribronchial and perivascular cuffing by lymphoid cells, mainly plasma cells, in parasitized lobes. Morphologically, this syngamid species differed from S. microtinae reported previously from the same host species as well as from other syngamids known from avian hosts. PMID:1548793

Sato, H; Kamiya, M

1992-01-01

151

The St. Lawrence Island famine and epidemic, 1878–80: a Yupik narrative in cultural and historical context.  

PubMed

A collaborative study of the Smithsonian Institution's ethnology collections has inspired the narration of Alaska Native oral traditions, including Yupik Elder Estelle Oozevaseuk's re-telling (in 2001) of the story of Kukulek village and the St. Lawrence Island famine and epidemic of 1878–80. The loss of at least 1,000 lives and all but two of the island's villages was a devastating event that is well documented in historical sources and archaeology, as well as multiple Yupik accounts. Yupiget have transmitted memories of extreme weather, bad hunting conditions, and a wave of fatal contagion that swept the island. The Kukulek narrative, with origins traceable to the late nineteenth century, provides a spiritual perspective on the disaster's underlying cause, found in the Kukulek people's disrespect toward the animal beings that sustained them. This paper explores the cultural and historical contexts of this narrative, and contrasts it with Western perspectives. PMID:21847843

Crowell, Aron L; Oozevaseuk, Estelle

2006-01-01

152

Description of Gyrodactylus mediotorus n. sp. (Monogenea: Gyrodactylidae) infecting spottail shiner (Notropis hudsonius) from the St. Lawrence River, Canada.  

PubMed

Gyrodactylus mediotorus n. sp. is described from the body, fins, and buccal cavity of the spottail shiner, Notropis hudsonius (Cyprinidae) from the St. Lawrence River, Quebec, Canada. Gyrodactylus mediotorus n. sp. is the first species of Gyrodactylus Nordmann, 1832 described from N. hudsonius and is characterized by large hamuli, large medial process of the ventral bar, narrow linguiform ventral bar membrane, large anterolateral processes, and marginal hooks with long shafts and distinctly shaped sickle. The species that most resembles Gyrodactylus mediotorus n. sp. is Gyrodactylus protuberus Rogers and Wellborn, 1965 described from the stargazing shiner, Notropis uranoscopus Suttkus, 1959. The 2 species can be differentiated based on the larger hamuli (68.4 vs. 64) and ventral bar (38.4 vs. 24) of Gyrodactylus mediotorus n. sp. and the shape of the marginal hooks which for Gyrodactylus mediotorus n. sp. has a slightly larger toe and a point which is not as angled. The morphological description is supplemented with 436 sequenced base pairs of the 18S gene (including the V4 region) as well as 1,041 sequenced base pairs spanning the complete ITS-1, 5.8S, and ITS-2 regions. BLAST (Basic Local Alignment Search Tool) searches failed to provide any close matches for either regions of DNA, with Gyrodactylus colemanensis infecting Salvelinus fontinalis being the most genetically similar for both the 18S (?91%, JF836090) and ITS (?84%, JF836142) rDNA regions. Gyrodactylus mediotorus n. sp. has been found infecting spottail shiners in the St. Lawrence River in low prevalence and intensities periodically over the last 15 yr. PMID:23883192

King, Stanley D; Marcogliese, David J; Forest, Jonathon J H; McLaughlin, J Daniel; Bentzen, Paul

2013-12-01

153

Influence of late-summer storms on the horizontal variability of phytoplankton pigment determined by coastal zone color scanner images in the Gulf of St. Lawrence, Canada  

Microsoft Academic Search

The western gulf of St. LAwrence (GSL) is characterized by high, persistent phytoplankton production and functions as the principal supplier of phytoplankton biomass for the central and eastern Gulf. The main objective of this study was to report on the evolution of a wind-induced phytoplankton bloom in this region. We used Coastal Zone Color Scanner images taken on 20, 22,

Cesar Fuentes-Yaco; Alain F. Vezina; Michel Gosselin; Yves Gratton; Pierre Larouche

1997-01-01

154

Seasonal changes in the sources and fluxes of dissolved inorganic carbon through the St. Lawrence River—isotopic and chemical constraint  

Microsoft Academic Search

The St. Lawrence River ranks 16th in the world rivers for its freshwater discharge into the ocean, but its particulate fluxes are relatively low due the upstream presence of the Great Lakes system. Using notably 13C measurements in total dissolved inorganic carbon (DIC) at several stations along stream, earlier studies provided information on dissolved inorganic carbon (DIC) fluxes through the

Jean-François Hélie; Claude Hillaire-Marcel; Bernard Rondeau

2002-01-01

155

Contrasting shell\\/tissue characteristics of Dreissena polymorpha and Dreissena bugensis in relation to environmental heterogeneity in the St. Lawrence River  

Microsoft Academic Search

The zebra mussel, Dreissena polymorpha, is widespread in the St. Lawrence River while the conspecific quagga mussel, Dreissena bugensis, is found only in the Lake Ontario outflow region of the river. This situation provided an opportunity to evaluate in situ environmental and interspecific heterogeneity in shell and tissue growth. Shell dry weight, carbon content, and shell strength of D. polymorpha

Andrew F. Casper; Ladd E. Johnson

2010-01-01

156

A processing plant survey of external lesions of American eels ( Anguilla rostrata) from Lake Ontario and the St. Lawrence River, Canada  

Microsoft Academic Search

Signs of decreasing landing and recruitment were observed in the last decade in American eels (Anguilla rostrata) from the St. Lawrence River basin, Canada. In order to verify if the declines were associated with high prevalence of diseases among commercial catches, a total of 12243 eels captured in five commercial fishing sites were inspected at two processing plants in 1992.

Lucie T Dutil; Catherine M Couillard; Denise Bélanger

1997-01-01

157

A telephone survey of eel fishermen regarding external lesions and mortalities of American eels ( Anguilla rostrata) from Lake Ontario and the St. Lawrence River basin, Canada  

Microsoft Academic Search

Signs of decreasing landings and recruitment have been observed during the last decade in American eels (Anguilla rostrata) from the St. Lawrence River basin, Canada. A study was undertaken to examine whether important manifestational diseases among commercial catches could be associated with these declines. During this survey, 56 fishermen from Lakes Ontario, Saint-François and Saint-Pierre, the Richelieu River, the Québec

Lucie Dutil; Denise Bélanger; Catherine M Couillard

1997-01-01

158

Winter Flow, Ice and Weather Conditions of the Upper St. Lawrence River, 1971-81. Volume I. Ice Cover Charts (Part A).  

National Technical Information Service (NTIS)

The International Section of the St. Lawrence River between Kingston and the Moses-Saunders Power Dam near Massena is the outlet of the Great Lakes. This river is being utilized for hydro-power production and serves as the only navigation passage for ship...

H. T. Shen G. C. Pasquarell R. W. Ruggles

1982-01-01

159

Influence of physicochemical factors on the distribution and biomass of invasive mussels ( Dreissena polymorpha and Dreissena bugensis ) in the St. Lawrence River  

Microsoft Academic Search

Twenty sites along the St. Lawrence River were sampled to determine if the distribution and abundance of invasive mussels (zebra mussel (Dreissena polymorpha) and quagga mussel (Dreissena bugensis)) are explained by physicochemical variables. Calcium concentration, substrate size, and depth independently explained significant propor- tions of variation in biomass for both species. Zebra mussel populations occurred at calcium levels as low

Lisa A. Jones; Anthony Ricciardi

2005-01-01

160

PCBs and PAHs in the Montreal Urban Community (Quebec, Canada) wastewater treatment plant and in the effluent plume in the St Lawrence River  

Microsoft Academic Search

Samples of raw and treated wastewater were collected at the Montreal Urban Community (Canada) sewage treatment plant between July and October 1993 and analysed for PCBs and PAHs. Water samples were also collected in the effluent plume in the St Lawrence River during the same period. The average concentrations of ?13 PCBs in raw wastewater and treated wastewater were 4.3

Thanh-Thao Pham; Suzie Proulx

1997-01-01

161

Influence of historical events and contemporary estuarine circulation on the genetic structure of the banded killifish ( Fundulus diaphanus ) in the  St. Lawrence River (Quebec, Canada)  

Microsoft Academic Search

Eight microsatellite markers were used to examine the historical and contemporary factors influencing the distri- bution of genetic variation within and among populations of Fundulus diaphanus(Lesueur, 1817) in the St. Lawrence River. Our results show that the contemporary hydrodynamics of the river affect levels of diversity and differentiation in this species. Genetic diversity increased towards downstream sites and levelled off

O. Rey; J. Turgeon

2007-01-01

162

Contaminant Residues in Snapping Turtle ( Chelydra s. serpentina ) Eggs from the Great Lakes–St. Lawrence River Basin (1999 to 2000)  

Microsoft Academic Search

To determine temporal and geographic variations of environmentally persistent pollutants, the concentrations of several contaminants were measured in snapping turtle eggs in 1999 and 2000. Contaminants included polychlorinated biphenyls (PCBs), non- ortho PCBs, polychlorinated dibenzodioxins and furans, organochlorine pesticides, and total mercury. Egg collection sites within the St. Lawrence Area of Concern (AOC) and the Territory of Akwesasne included Turtle

S. L. Ashpole; C. A. Bishop; R. J. Brooks

2004-01-01

163

St. Johns Estuary: Estuarine Benthic Macroinvertebrates Phase 2 Final Report. Special Publication SJ2012-SP4.  

National Technical Information Service (NTIS)

Benthic macrofaunal communities can be strongly influenced by changes in freshwater inflows in an estuary. Macrofauna are affected by changes in estuarine condition (including nutrient concentrations, sediment supply and salinity) caused by variation in f...

J. B. Pollack P. A. Montagna T. A. Palmer

2011-01-01

164

Charcoal-Based Paleoecological Investigation of the Holocene Fire Regime of St. Lawrence Islands National Park, Southeastern Ontario  

NASA Astrophysics Data System (ADS)

Wildfire is an ecological disturbance that plays a role in ecosystem function and is complexly associated with climate and vegetation. The study of long-term fire regimes can provide information about the range of conditions that have existed in an environment and supply context for future shifts in those conditions. There has been little research of paleofire in Southeastern Ontario, Canada, though it is a relevant process. To address the gap, our project is investigating the long-term history of fire during the Holocene within this area using paleolimnological methods. The primary objective is the reconstruction of the fire frequency of a small watershed in this region over approximately the past 10000 years. The results will be applied to the ecological management of St. Lawrence Islands National Park. Analysis of the macroscopic charcoal content in lake sediment is the primary technique. A surface sediment core (0.65m) and a long sediment core (4.15m) were extracted in Summer 2008 from Mud Lake, a small (2ha) lake approximately 20-40km from St. Lawrence Islands National Park territory. Preliminary analysis of the charcoal content indicates no local fires for the past several hundred years. Initial results also indicate a fire return interval on the order of hundreds of years. The findings coordinate with the region's humid, continental climate and mixed forest. AMS radiocarbon and 210Pb dating provide a chronology for the sediment cores, and its magnetic susceptibility has also been analyzed. The study will contribute to the park's fire management and ecological restoration practices. The long-term history of fire is of particular interest as a provincially rare species, Pinus rigida, the pitch pine, has numerous populations in the park boundaries and adjacent to the lake site and has been present in this region for several thousand years. As this species relies on fire for its life cycle, knowledge of the fire patterns that have existed in its range will assist in managing its restoration. Furthermore, the results may aid in addressing future environmental variability and in managing the overall ecological integrity of the region.

Ellwood, S. M.; Hallett, D. J.; Cumming, B. F.

2009-05-01

165

Spatial dynamics of biogeochemical processes in the St. Louis River freshwater estuary  

EPA Science Inventory

In the Great Lakes, river-lake transition zones within freshwater estuaries are hydrologically and biogeochemically dynamic areas that regulate nutrient and energy fluxes between rivers and Great Lakes. The goal of our study was to characterize the biogeochemical properties of th...

166

Parasite fauna of Etheostoma nigrum (Percidae: Etheostomatinae) in localities of varying pollution stress in the St. Lawrence River, Quebec, Canada.  

PubMed

Parasite communities were examined in johnny darters (Etheostoma nigrum) collected from five localities in the St. Lawrence River in southwestern Quebec: two reference localities, one polluted locality upstream of the Island of Montreal and downstream of industrial and agricultural activity, and two polluted localities downstream of the Island of Montreal in the plume from the wastewater treatment facility. Twenty-four helminth species were found. Fish from the upstream polluted locality had the highest parasite species richness and total parasite numbers, and fish from the downstream polluted localities the lowest. Nonmetric multivariate analyses were conducted using square-root-transformed Bray-Curtis dissimilarity index. An analysis of similarity, dendrogram of centroids, and a permutational multivariate analysis of variance with contrasts all showed that fish from the reference localities had different parasite community composition than those from the polluted localities, and fish from the upstream polluted locality had different parasite communities than fish from the downstream polluted localities. Differences between reference and polluted localities were mainly due to higher abundances of the brain-encysting trematode, Ornithodiplostomum sp., at the reference localities. Differences between upstream and downstream polluted localities were mainly due to a higher diversity and abundance of trematodes in fish at the upstream locality. PMID:20422221

Krause, Rachel J; McLaughlin, J Daniel; Marcogliese, David J

2010-07-01

167

Estimation, analysis, sources, and verification of consumptive water use data in the Great Lakes-St. Lawrence River basin  

USGS Publications Warehouse

The Great Lakes-St. Lawrence River basin provides water for many uses and for wildlife habitat; thus many groups have developed strategies to manage the basin 's water resource. The International Joint Commission (IJC) is reviewing and comparing available consumptive-use data to assess the magnitude and effect of consumptive uses under present projected economic and hydraulic conditions on lake levels. As a part of this effort, the U.S. Geological Survey compared its own estimates of consumptive use in the United States with those generated by (1) the International Great Lakes Diversions and (2) the IJC. The U.S. Geological Survey also developed two methods of calculating consumptive-use projections for 1980 through 2000; one method yields an estimate of 6,490 cu ft/s for the year 2000; the other yields an estimate of 8,330 cu ft/s. These two projections could be considered the upper and lower limits for the year 2000. The reasons for the varying estimates are differences in (1) methods by which base year values were developed, and (2) the methods or models that were used to project consumptive-use values for the future. Acquisition of consumptive-use data from water users or governmental agencies or ministries would be desirable to minimize reliance on estimates. (USGS)

Snavely, D. S.

1988-01-01

168

Shipping noise in whale habitat: characteristics, sources, budget, and impact on belugas in Saguenay-St. Lawrence Marine Park hub.  

PubMed

A continuous car ferry line crossing the Saguenay Fjord mouth and traffic from the local whale-watching fleet introduce high levels of shipping noise in the heart of the Saguenay-St. Lawrence Marine Park. To characterize this noise and examine its potential impact on belugas, a 4-hydrophone array was deployed in the area and continuously recorded for five weeks in May-June 2009. The source levels of the different vessel types showed little dependence on vessel size or speed increase. Their spectral range covered 33 dB. Lowest noise levels occurred at night, when ferry crossing pace was reduced, and daytime noise peaked during whale-watching tour departures and arrivals. Natural ambient noise prevailed 9.4% of the time. Ferry traffic added 30-35 dB to ambient levels above 1 kHz during crossings, which contributed 8 to 14 dB to hourly averages. The whale-watching fleet added up to 5.6 dB during peak hours. Assuming no behavioral or auditory compensation, half of the time, beluga potential communication range was reduced to less than ~30% of its expected value under natural noise conditions, and to less than ~15% for one quarter of the time, with little dependence on call frequency. The echolocation band for this population of belugas was also affected by the shipping noise. PMID:22779457

Gervaise, Cédric; Simard, Yvan; Roy, Nathalie; Kinda, Bazile; Ménard, Nadia

2012-07-01

169

Crocodiles count on it: Regulation of discharge to Lake St Lucia Estuary by a South African peatland  

NASA Astrophysics Data System (ADS)

The Mfabeni mire is located within the iSimangaliso Wetland Park in north-eastern KwaZulu-Natal Province on the Indian Ocean sea-board of South Africa. This mire complex includes open peatland with occurrences of sedge communities, Sphagnum (rare in South Africa), and swamp forest which is common in the region (but rare in South Africa). It is one of the largest (1650 ha), thickest (10.8 m of peat) and the oldest (~45,000 years Before Present) known peatlands in South Africa. The mire is almost pristine, with very few disturbances. In the past the surrounding area supported pine plantations but these alien trees were recently removed, with conservation and tourism the primary designated activities. Surface and groundwater exchanges to and within the mire and its surrounding coastal dune landscape were studied. Profiles of electrical conductivity and major cations and anions, as well as natural isotopes (?2H and ?18O) in water samples of ground and surface water were also analysed to develop a conceptual model of the system’s hydrological function. Water efflux from an inland dune complex provides substantial recharge towards Mfabeni, while coastward hydraulic gradients from the dune complex through the wetland are evident. Consequently, the linkages between the dune system and Mfabeni, and the peatland’s water regulation function, dictate the nature and magnitude of the local freshwater discharge to the estuary, and internal water exchanges that control peatland ecological function. The hydrograph from the stream outlet indicate an initial rapid response in increased flows after major rainfall events but with a delayed drawdown over time reflecting the contribution of the relatively large size of the mire (comprising 38% of the catchment) in attenuating flood events and ensuring sustained flow to the estuary. Freshwater discharge from the Mfabeni mire to the St. Lucia estuary, which has provided refuge for aquatic species during periods of drought, may become crucial under a more erratic climate.

Price, J. S.; Grundling, P.; Grootjans, A.

2010-12-01

170

Variations in water temperatures and levels in the St. Lawrence River (Québec, Canada) and potential implications for three common fish species  

Microsoft Academic Search

The implications for fish populations of long- (multi-decadal, 1919–2007), medium- (inter-annual) and short- (seasonal, daily)\\u000a term variations in water temperatures and levels were examined in the St. Lawrence River (SLR). The effects of the seasonal\\u000a thermal regime of the SLR and its tributaries on the thermal budgets of resident and migrating fish were contrasted. Over\\u000a the 1919–2007 period, the mean

Christiane Hudon; Alain Armellin; Pierre Gagnon; Alain Patoine

2010-01-01

171

Meltwater discharge and the triggering of Younger Dryas : new data on the chronology of Champlain Sea transgression in the St-Lawrence River Valley  

Microsoft Academic Search

Accurate chronology of ice retreat is crucial to understand the Ocean-Atmosphere couple at the end of the Pleistocene. The St-Lawrence River Valley is key in this regard, and two sedimentary sequences from Mount Saint-Hilaire, in the middle of the valley, contain a record that sheds new lignt on ice retreat and the penecontemporaneous proglacial marine invasion. Basal AMS-dates on terrestrial

P. Richard; S. Occhietti

2004-01-01

172

Hazard assessment of a simulated oil spill on intertidal areas of the St. Lawrence River with SPMD-TOX  

USGS Publications Warehouse

Phytoremediation in a simulated crude oil spill was studied with a "minimalistic" approach. The SPMD-TOX paradigm - a miniature passive sorptive device to collect and concentrate chemicals and microscale tests to detect toxicity - was used to monitor over time the bioavailability and potential toxicity of an oil spill. A simulated crude oil spill was initiated on an intertidal freshwater grass-wetland along the St. Lawrence River southwest of Quebec City, Quebec, Canada. Several phytoremediation treatments were investigated; to dissipate and ameliorate the spill, treatments included nutrient amendments with inorganic nitrogen sources (ammonium nitrate and sodium nitrate) and phosphate (super triple phosphate) with and without cut plants, with natural attenuation (no phytoremedial treatment) as a control. Sequestered oil residues were bioavailable in all oil-treated plots in Weeks 1 and 2. Interestingly, the samples were colored and fluoresced under ultraviolet light. In addition, microscale tests showed that sequestered residues were acutely toxic and genotoxic, as well as that they induced hepatic P450 enzymes. Analysis of these data suggested that polycyclic aromatic hydrocarbons were among the bioavailable residues sequestered. In addition, these findings suggested that the toxic bioavailable fractions of the oil spill and degradation products dissipated rapidly over time because after the second week the water column contained no oil or detectable degradation products in this riverine intertidal wetland. SPMD-TOX revealed no evidence of bioavailable oil products in Weeks 4, 6, 8, and 12. All phytoremediation efforts appeared to be ineffective in changing either the dissipation rate or the ability to ameliorate the oil toxicity. SPMD-TOX analysis of the water columns from these riverine experimental plots profiled the occurrence, dissipation, and influence of phytoremediation on the bioavailability and toxicity of oil products (parent or degradation products. ?? 2004 Wiley Periodicals, Inc.

Johnson, B. T.; Petty, J. D.; Huckins, J. N.; Lee, K.; Gauthier, J.

2004-01-01

173

History of the atmospheric deposition of major and trace elements in the industrialized St. Lawrence Valley, Quebec, Canada  

NASA Astrophysics Data System (ADS)

The history of the atmospheric deposition of major and trace elements over southwestern Quebec, Canada, was reconstructed using multielemental analysis of lacustrine sediments sampled in a small and undisturbed lake located on top of a mountain in the heart of the industrialized St. Lawrence Valley. Acid leachable and residual elements were extracted from a 37-cm long core (1-cm resolution) using clean techniques and analyzed by inductively coupled plasma mass spectrometry. Organic matter and sulfur concentrations were high and played a major role in the low postdepositional diagenetic remobilization of many trace elements. Sulfur, manganese, iron, arsenic, molybdenum and barium displayed a high mobility making it exceedingly difficult to infer unambiguously time-dependent changes in atmospheric deposition for these elements. Atmospheric deposition rates for the less mobile elements (e.g., potassium, vanadium, chromium, cobalt, nickel, copper, zinc, rubidium, cadmium, tin, antimony, mercury, thallium, lead, and bismuth) increased regularly between 1942 and 1960-1975 in the Lake Hertel area and then stabilized for most of these elements, with the exception of nickel, copper, zinc and tin. Lead deposition rate was reduced by about 25% between 1982 and 1995, and a slight decreasing trend was also found for cobalt, mercury, and thallium during the same period. Present-day atmospheric deposition of metals directly on the lake surface represents a small percentage of the sedimentary deposition rates at this location. Deposition followed by surface runoff and outwash of terrestrial organic and inorganic matter most likely is the driving mechanism leading to the non-diagenetic enrichment of metals in Lake Hertel sediments.

Gélinas, Yves; Lucotte, Marc; Schmit, Jean-Pierre

174

(222)Rn activity in groundwater of the St. Lawrence Lowlands, Quebec, eastern Canada: relation with local geology and health hazard.  

PubMed

One hundred ninety-eight groundwater wells were sampled to measure the (222)Rn activity in the region between Montreal and Quebec City, eastern Canada. The aim of this study was to relate the spatial distribution of (222)Rn activity to the geology and the hydrogeology of the study area and to estimate the potential health risks associated with (222)Rn in the most populated area of the Province of Quebec. Most of the groundwater samples show low (222)Rn activities with a median value of 8.6Bq/L. Ninety percent of samples show (222)Rn activity lower than 100Bq/L, the exposure limit in groundwater recommended by the World Health Organization. A few higher (222)Rn activities (up to 310Bq/L) have been measured in wells from the Appalachian Mountains and from the magmatic intrusion of Mont-Saint-Hilaire, known for its high level of indoor radon. The spatial distribution of (222)Rn activity seems to be related mainly to lithology differences between U-richer metasediments of the Appalachian Mountains and magmatic intrusions and the carbonaceous silty shales of the St. Lawrence Platform. Radon is slightly enriched in sodium-chlorine waters that evolved at contact with clay-rich formations. (226)Ra, the parent element of (222)Rn could be easily adsorbed on clays, creating a favorable environment for the production and release of (222)Rn into groundwater. The contribution of groundwater radon to indoor radon or by ingestion is minimal except for specific areas near Mont-Saint-Hilaire or in the Appalachian Mountains where this contribution could reach 45% of the total radioactive annual dose. PMID:24973780

Pinti, Daniele L; Retailleau, Sophie; Barnetche, Diogo; Moreira, Floriane; Moritz, Anja M; Larocque, Marie; Gélinas, Yves; Lefebvre, René; Hélie, Jean-François; Valadez, Arisai

2014-10-01

175

Evaluation of liver histopathology and EROD activity in St. Lawrence lake sturgeon (Acipenser fulvescens) in comparison with a reference population  

SciTech Connect

In an attempt to evaluate the effects of contaminants on the lake sturgeon Acipenser fulvescens, fish were netted from two sites: Riviere des Prairies, confluent with the St. Lawrence River near Montreal, and a reference site on the upper reaches of the Ottawa River in the La Verendrye Park. Livers of fish collected from the Riviere des Prairies were difficult to homogenize, and they left behind strands of what appeared to be connective tissue. Suspecting hepatic fibrosis, the authors decided to evaluate the livers for histopathologic changes. Nineteen adult lake sturgeon (eleven male and eight female) were examined. Following fixation, routine processing, sectioning, and staining with hematoxylin and eosin, microscopic evaluation revealed the following: Sections taken from livers of fish from the Riviere des Prairies site showed excessive fat accumulation and often severe chronic-active cholangiohepatitis. Bile duct proliferation (p < 0.0001), periportal fibrosis (p < 0.0001), inflammation (p < 0.001), and fat accumulation (p < 0.05) were more pronounced in the fish from the Riviere des Prairies site. Melano-macrophage centers appeared to be both paler and gave the appearance of fewer numbers (p < 0.01). Livers from lake sturgeon taken from the reference site had a more normal appearance. The EROD levels were also significantly induced in these fish (reference 3.39 {+-} 0.57; Riviere des Prairies site 8.21 {+-} 0.87 pmol/mg protein/min; p < 0.0005). The EROD levels positively correlated with bile duct proliferation (r{sup 2} = 0.44; p = 0.001) and periportal fibrosis (r{sup 2} = 0.41; p = 0.002). Despite the statistical associations above, the authors cannot categorically state that contaminants are the sole cause of the lesions seen.

Rousseaux, C.G. [Univ. of Saskatchewan, Saskatoon, Saskatchewan (Canada)]|[GlobalTox International Consultants, Inc., Ottawa, Ontario (Canada)]|[Univ. of Quebec, Montreal, Quebec (Canada); Branchaud, A.; Spear, P.A. [Univ. of Quebec, Montreal, Quebec (Canada)

1995-05-01

176

Novel flame retardants in urban-feeding ring-billed gulls from the St. Lawrence River, Canada.  

PubMed

This study investigated the occurrence of a comprehensive suite of polybrominated diphenyl ethers (PBDEs) and current-use flame retardants (FRs) in ring-billed gulls breeding in a highly industrialized section of the St. Lawrence River, downstream from Montreal (QC, Canada). Despite major point-sources and diffuse contamination by FRs, nearly no FR data have been reported in birds from this area. Bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (BEHTBP) was detected in 89% of ring-billed gull livers (mean: 2.16 ng/g ww; max: 17.6 ng/g ww). To our knowledge, this is the highest detection frequency and highest concentrations reported thus far in any avian species or populations. Dechlorane Plus (DP) isomers were also particularly abundant (anti-DP detected in 100% and syn-DP in 93% of livers). Other detected FR compounds (3-14% detection) included 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EHTBB), hexachlorocyclopentenyl-dibromocyclooctane (HCDBCO) and ?-1,2-dibromo-4-(1.2-dibromoethyl)-cyclohexane (?-TBECH). Mean BDE-209 (57.2 ± 12.2 ng/g ww) in ring-billed gull livers was unexpectedly high for this midtrophic gull species, exceeding levels reported in several apex raptors such as peregrine falcons. BDE-209's relative contribution to ?PBDEs was on average 25% (exceeding BDE-47 and BDE-99) and contrasted with profiles typically reported for fish-eating gull species. The present study highlighted preoccupying gaps in upcoming FR regulations and stressed the need for further investigation of the sources of FR exposure in highly urbanized areas. PMID:22845168

Gentes, Marie-Line; Letcher, Robert J; Caron-Beaudoin, Elyse; Verreault, Jonathan

2012-09-01

177

The ecology of Echinococcus multilocularis (Cestoda: Taeniidae) on St. Lawrence Island, Alaska. II. Helminth populations in the definitive host.  

PubMed

The helminths of 1,579 arctic foxes from St. Lawrence Island were investigated by standard methods. The foxes, obtained mainly during the winter from fur trappers, harbored 22 species of helminths. Four of those were trematodes, viz., Maritrema afanassjewi Belopol'skaia, 1952, Orthosplanchnus pygmaeus Iurakhno, 1967, Plagiorchis elegans (Rudolphi, 1802) and Alaria marcianae (LaRue, 1917), each of which occurred in a single host. Two species of cestodes, Diphyllobothrium dendriticum (Nitzsch, 1824) and Mesocestoides kirbyi Chandler, 1940, were uncommon (in 2.7 and 1.3% of the foxes, respectively). Taenia polyacantha Leuckart, 1856 and Echinococcus multilocularis Leuckart, 1863 were present in about 80% of the foxes, and Taenia crassiceps (Zeder, 1800) in less than 10%. The specimens of Taenia spp. from the autumn-winter sample were usually destrobilate. In about 2% of the foxes, acanthocephalans of six species occurred. Four of those, of the genus Corynosoma Lühe, 1904, were common in marine mammals of the region; a fifth, Corynosoma clavatum Goss, 1940, has been reported previously only from marine birds of the Southern Hemisphere; and the sixth, Polymorphus cf. minutus (Goeze, 1782), has been found widely in waterfowl of the Northern Hemisphere. Of the nematodes, Sobolophyme baturini Petrov, 1930, Cylicospirura felineus (Chandler, 1925), and Physaloptera sp. were rare (with each in only one to three foxes). Trichinella nativa Boev et Britov, 1972 and Crenosoma vulpis (Dujardin, 1844) were uncommon (1.5 and 4%, respectively). The nematodes most often present were Toxascaris leonina (von Linstow, 1902) (89%) and Uncinaria stenocephala (Railliet, 1884) (40%). Several of the rare to uncommon helminths probably were transported to the island by foxes immigrating from the adjacent continents via the pack ice. PMID:2080830

Rausch, R L; Fay, F H; Williamson, F S

1990-01-01

178

46 CFR 401.405 - Basic rates and charges on the St. Lawrence River and Lake Ontario.  

Code of Federal Regulations, 2013 CFR

...Lawrence River and Lake Ontario. 401.405 Section 401.405 Shipping COAST GUARD (GREAT LAKES PILOTAGE), DEPARTMENT OF HOMELAND SECURITY GREAT LAKES PILOTAGE REGULATIONS Rates, Charges, and Conditions for Pilotage Services §...

2013-10-01

179

A comparison of biofilms from macrophytes and rocks for taste and odour producers in the St. Lawrence river.  

PubMed

Given their widespread and prolific annual development in the St. Lawrence River (SLR), macrophytes (i.e. submerged aquatic plants) represent large surface areas for biofilm growth and potentially important sites for associated production of taste and odour (T&O) compounds. We therefore evaluated the importance of submerged macrophytes and their associated biofilms for production of T&O compounds, 2-methylisoborneol (MIB) and geosmin (GM), compared with biofilms from adjacent rocks. We also tested the hypothesis that production of these compounds would differ between macrophyte species, based on the premise that they are not inert substrates but directly influence the communities that colonise their surfaces. Samples collected from transects across the SLR between Kingston and Cornwall, ON were dominated by the flat-bladed Vallisneria spp., and the leafed Myriophyllum spicatum, Elodea canadensis, Chara spp., Potamgeton spp., and Ceratophyllum spp. Overall, MIB and GM levels in biofilms ranged widely between samples. Expressed per g dry weight of biofilm, median levels from macrophyte were 50 (range 1-5000) ng MIB g(-1) and 10 (<1 to 580) ng GM g(-1) compared with 50 (range 5-970) ng MIB g(-1) and 160 (1-1600) ng GM g(-1) from rocks. Based on non-parametric statistical analysis, levels of GM were higher on a g dry weight basis in biofilms from rocks than macrophytes (P = 0.02), but MIB levels were similar (P = 0.94). However, when normalised for differences in substrate surface area (i.e. ng cm(-2)), levels of both MIB and GM were higher in biofilms from rocks than from macrophytes (P < 0.01). There were no discernable differences in MIB and GM concentrations from biofilms of different macrophytes based on either g dry weight sample or surface area (P > 0.05). Overlying water (OLW) concentrations ranged between 2-45 ng L(-1) for MIB and 5-30 ng L(-1) for GM and were not correlated with levels in adjacent biofilms. However, OLW concentrations peaked in shallow, low energy embayments consistent with enhanced production and release of MIB and GM in nearshore areas. The results support our previous work showing the importance of biofilms on various surfaces (rocks, macrophytes and zebra mussels) for MIB and GM production in the SLR, but suggest that inert surfaces like rocks are more productive sites per unit surface area than macrophytes. PMID:17489389

Ridal, J J; Watson, S B; Hickey, M B C

2007-01-01

180

Modeling wetland plant community response to assess water-level regulation scenarios in the Lake Ontario-St. Lawrence River basin  

USGS Publications Warehouse

The International Joint Commission has recently completed a five-year study (2000-2005) to review the operation of structures controlling the flows and levels of the Lake Ontario - St. Lawrence River system. In addition to addressing the multitude of stakeholder interests, the regulation plan review also considers environmental sustainability and integrity of wetlands and various ecosystem components. The present paper outlines the general approach, scientific methodology and applied management considerations of studies quantifying the relationships between hydrology and wetland plant assemblages (% occurrence, surface area) in Lake Ontario and the Upper and Lower St. Lawrence River. Although similar study designs were used across the study region, different methodologies were required that were specifically adapted to suit the important regional differences between the lake and river systems, range in water-level variations, and confounding factors (geomorphic types, exposure, sediment characteristics, downstream gradient of water quality, origin of water masses in the Lower River). Performance indicators (metrics), such as total area of wetland in meadow marsh vegetation type, that link wetland response to water levels will be used to assess the effects of different regulation plans under current and future (climate change) water-supply scenarios.

Hudon, Christiane; Wilcox, Douglas; Ingram, Joel

2006-01-01

181

Predation on ruffe by native fishes of the St. Louis River Estuary, Lake Superior, 1989-1991  

USGS Publications Warehouse

The ruffe Gymnocephalus cernuus, an exotic Eurasian percid, recently became established in the St. Louis River estuary, Lake Superior, after accidental introduction. Management action (catch regulations and stocking) were enacted in 1989 to increase the density of top-level predators in the estuary, and thus to increase predation on ruffe. We conducted a field and laboratory study to determine if, and to what extent, native piscivores consume ruffe. Stomachs of 3,669 predators were examined in 1989-1991. Ruffe occurred in 6.7% of burbot Lota lota, 5.8% of bullheads Ictalurus spp., 4.7% of smallmouth bass Micropterus dolomieu, 2.6% of northern pike Esox lucius, 2.6% of black crappies Pomoxis nigromaculatus, and 1.3% of yellow perch Perca flavescens (4.5% after 1989) captured during the 3-year study. No ruffe were found in 967 stomachs of walleyes Stizostedion vitreum examined. Ruffe were 22.7% of the diet (by weight) of bullheads (during the only year bullheads were captured) and 0.1-17.9% of the diet of northern pike. Ruffe were 0.9-24.5% of the diet of smallmouth bass that contained fish, 1.5-6.9% of yellow perch that contained fish, and 0.0-10.9% of black crappies that contained fish. Most ruffe eaten were age-0 or small age-1 fish. In the laboratory, walleyes that were first fed soft-rayed prey or that were also offered soft-rayed prey consumed very few ruffe, whereas walleyes that were first fed spiny-rayed yellow perch or were also offered yellow perch consumed about equal numbers of ruffe and yellow perch. Northern pike and burbot consumed about equal numbers of ruffe and yellow perch in the laboratory. It is unlikely that predation will effectively control the initial expansion of ruffe in other areas of the Great Lakes because native predators initially consume few ruffe, especially if more preferred soft-rayed prey are available.

Ogle, Derek H.; Selgeby, James H.; Savino, Jacqueline F.; Newman, Raymond M.; Henry, Mary G.

1996-01-01

182

Application of Acoustic and Optic Methods for Estimating Suspended-Solids Concentrations in the St. Lucie River Estuary, Florida  

USGS Publications Warehouse

Acoustic and optic methods were applied to estimate suspended-solids concentrations in the St. Lucie River Estuary, southeastern Florida. Acoustic Doppler velocity meters were installed at the North Fork, Speedy Point, and Steele Point sites within the estuary. These sites provide varying flow, salinity, water-quality, and channel cross-sectional characteristics. The monitoring site at Steele Point was not used in the analyses because repeated instrument relocations (due to bridge construction) prevented a sufficient number of samples from being collected at the various locations. Acoustic and optic instruments were installed to collect water velocity, acoustic backscatter strength (ABS), and turbidity data that were used to assess the feasibility of estimating suspended-solids concentrations in the estuary. Other data collected at the monitoring sites include tidal stage, salinity, temperature, and periodic discharge measurements. Regression analyses were used to determine the relations of suspended-solids concentration to ABS and suspended-solids concentration to turbidity at the North Fork and Speedy Point sites. For samples used in regression analyses, measured suspended-solids concentrations at the North Fork and Speedy Point sites ranged from 3 to 37 milligrams per liter, and organic content ranged from 50 to 83 percent. Corresponding salinity for these samples ranged from 0.12 to 22.7 parts per thousand, and corresponding temperature ranged from 19.4 to 31.8 ?C. Relations determined using this technique are site specific and only describe suspended-solids concentrations at locations where data were collected. The suspended-solids concentration to ABS relation resulted in correlation coefficients of 0.78 and 0.63 at the North Fork and Speedy Point sites, respectively. The suspended-solids concentration to turbidity relation resulted in correlation coefficients of 0.73 and 0.89 at the North Fork and Speedy Point sites, respectively. The adequacy of the empirical equations seems to be limited by the number and distribution of suspended-solids samples collected throughout the expected concentration range at the North Fork and Speedy Point sites. Additionally, the ABS relations for both sites seem to overestimate at the low end and underestimate at the high end of the concentration range. Based on the sensitivity analysis, temperature had a greater effect than salinity on estimated suspended-solids concentrations. Temperature also appeared to affect ABS data, perhaps by changing the absorptive and reflective characteristics of the suspended material. Salinity and temperature had no observed effects on the turbidity relation at the North Fork and Speedy Point sites. Estimates of suspended-solids concentrations using ABS data were less 'erratic' than estimates using turbidity data. Combining ABS and turbidity data into one equation did not improve the accuracy of results, and therefore, was not considered.

Patino, Eduardo; Byrne, Michael J.

2004-01-01

183

Temporal and spatial distribution and production of dissolved gaseous mercury in the Bay St. François wetland, in the St. Lawrence River, Quebec, Canada  

Microsoft Academic Search

Wetlands are valued for their high biodiversity and for their ecosystem services. However, we still do have a poor understanding of their role in the redox transformation of contaminants such as mercury, particularly in fluvial settings. Seasonal and spatial variations in dissolved gaseous mercury (DGM) distribution and production were studied in the Bay St. François, a wetland in the St.

Edenise Garcia; Jerôme Laroulandie; Xavier R. Saint-Simon; Marc Amyot

2006-01-01

184

Continuous analysis of dissolved gaseous mercury and mercury volatilization in the upper St. Lawrence River: exploring temporal relationships and UV attenuation.  

PubMed

The formation and volatilization of dissolved gaseous mercury (DGM) is an important mechanism by which freshwaters may naturally reduce their mercury burden. Continuous analysis of surface water for diurnal trends in DGM concentration (ranging from 0 to 60.4 pg L(-1); n=613), mercury volatilization (ranging from 0.2 to 1.1 ng m(-2) h(-1); n=584), and a suite of physical and chemical measurements were performed during a 68 h period in the St. Lawrence River near Cornwall (Ontario, Canada) to examine the temporal relationships governing mercury volatilization. No lag-time was observed between net radiation and OGM concentrations (highest cross-correlation of 0.817), thus supporting previous research indicating faster photoreduction kinetics in rivers as compared to lakes. A significant lag-time (55-145 min; maximum correlation = 0.625) was observed between DGM formation and mercury volatilization, which is similar to surface water Eddy diffusion times of 42-132 min previously measured in the St. Lawrence River. A depth-integrated DGM model was developed using the diffuse integrated vertical attenuation coefficients for UVA and UVB (K(dI UVA) = 1.45 m(-1) K(dI UVB)= 3.20 m(-1)) Low attenuation of solar radiation was attributed to low concentrations of dissolved organic carbon (mean = 2.58 mg L(-1) and particulate organic carbon (mean = 0.58 mg L(-1) in the St. Lawrence River. The depth-integrated DGM model developed found that the top 0.3 m of the water column accounted for only 26% of the total depth-integrated DGM. A comparison with volatilization data indicated that a large portion (76% or 10.5 ng m(-2) of the maximum depth-integrated DGM (13.8 ng m(-2))is volatilized over a 24 h period. Therefore, at least 50% of all DGM volatilized was produced at depths below 0.3 m. These results highlight the importance of solar attenuation in regulating DGM formation with depth. The results also demonstrate both the fast formation of DGM in rivers and the importance of understanding DGM dynamics with depth as opposed to surface waters. PMID:17822100

O'Driscoll, N J; Poissant, L; Canário, L; Ridal, J; Lean, D R S

2007-08-01

185

Endocrine and metabolic dysfunction in yellow perch, Perca flavescens, exposed to organic contaminants and heavy metals in the St. Lawrence River  

SciTech Connect

The endocrine and biochemical responses to the acute stress of capture and handling were investigated in sexually mature and in immature male and female yellow perch, Perca flavescens, from a site contaminated by organic contaminants (PAHs and PCBs) and heavy metals (Hg, Cd, As, and Zn) and from a reference site in the St. Lawrence River. Following a standardized capture and handling stress, fish from the contaminated site did not exhibit the expected physiological stress response observed in fish from the reference site. Blood cortisol and thyroxine levels were lower, and liver glycogen stores were greater in mature males and females, as well as in the immature fish from the contaminated site, compared to the reference site. Fish from the contaminated site also had smaller gonads and lower condition factor. The impaired ability to elevate blood cortisol in response to an acute stress may be used as a biomarker of toxic stress in health assessment of feral fish from polluted environments.

Hontela, A.; Duclos, D.; Fortin, R. [Univ. du Quebec, Montreal, Quebec (Canada). Dept. Sciences Biologiques; Dumont, P. [Ministere du Loisir, Montreal, Quebec (Canada)

1995-04-01

186

Supplementary Environmental Baseline Studies and Evaluation of the St. Mary's River 1980. Great Lakes-St. Lawrence Seaway Navigation Season Extension Program.  

National Technical Information Service (NTIS)

The purpose of this study was to expand the existing biological, physical and chemical data for the Middle Neebish Channel in the St. Marys River to help determine environmental effects of suspension and re-distribution of sediments resulting from propose...

C. D. McNabb C. R. Liston D. E. Ashton T. Batterson W. G. Duffy

1981-01-01

187

St  

Cancer.gov

St. Joseph Hospital, Orange, California St. Joseph Hospital Cancer Center 1100 West Stewart Drive Orange CA 92863-5600 www.sjo.org • Larry Ainsworth, President and CEO, St. Joseph Hospital • James Padova, MD, Cancer Program Medical Director

188

Les échanges surface-atmosphère du mercure gazeux dans l'écosystème lac Ontario\\/fleuve Saint-Laurent Mercury Surface-Atmosphère Gas Exchange in Lake Ontario\\/St. Lawrence River Ecosystem  

Microsoft Academic Search

SUMMARY This paper présents and discusses mercury surface-atmosphère gas exchange in Lake Ontario\\/St. Lawrence River ecosystem. Atmospheric sources are recognised to be significant in the cycling of global mercury. Being volatile in its elemental and dimethylated forms, mercury is distributed Worldwide. The dominant form of mercury in the atmosphère is gaseous elemental mercury (Hg(°) (- 98%). Cycling of atmospheric mercury

L. POISSANT

189

Superfund Record of Decision (EPA Region 2): General Motors/Central Foundry Division site, St. Lawrence County, Massena, NY. (First remedial action), December 1990  

SciTech Connect

The 270-acre General Motors/Central Foundry Division site is an active aluminum casting plant in Massena, St. Lawrence County, New York. The site overlies a surficial alluvial aquifer and is adjacent to wetlands, both of which have been contaminated. Additional onsite features of concern include the unlined North and East Disposal Areas and the Industrial Landfill, which contain contaminated soil, debris, sludge; four unlined Industrial Lagoons, which contain contaminated liquids, sludge, and soil; the rivers and creek which contains contaminated sediment; contaminated soil on the St. Regis Mohawk Reservation and on General Motors property; and contaminated associated wetlands. The Record of Decision (ROD) provides a final remedy for all site areas and media except the East Disposal Area and the Industrial Landfill, which will be addressed in a subsequent ROD. The primary contaminants of concern affecting the soil, sediment, sludge, debris, ground water, and surface water are PCBs, and to a much lesser degree, VOCs including TCE; and other organics including PAHs, and phenols. The selected remedial action for this site is included.

Not Available

1990-12-17

190

14C chronology for ice retreat and inception of Champlain Sea in the St. Lawrence Lowlands, Canada  

Microsoft Academic Search

AMS radiocarbon cross-dating of plant debris and marine shells trapped in a lake basin on Mount St. Hilaire (Québec, Canada) provides a direct assessment of a reservoir effect totaling ca. 1800 14C years during the early stage of Champlain Sea. Pollen-based extrapolation of bottommost ages on terrestrial plant macrofossils in sediments of this lake, and of another lake nearby support

Pierre J. H. Richard; Serge Occhietti

2005-01-01

191

St  

Cancer.gov

St. Joseph Hospital Cancer Institute Physician Conditions of Participation A. PREAMBLE The vision of St. Joseph Hospital Cancer Institute is to attain the highest level of clinical excellence while providing an exceptional patient

192

Putting oxygen and temperature thresholds of marine animals in context of environmental change in coastal seas: a regional perspective for the Scotian Shelf and Gulf of St. Lawrence  

NASA Astrophysics Data System (ADS)

We surveyed the literature in order to compile reported oxygen, temperature, salinity and depth preferences and thresholds of important marine species found in the Gulf of St. Lawrence and the Scotian Shelf regions of the northwest North Atlantic. We determined species importance based on the existence of a commercial fishery, a threatened or at risk status, or by meeting the following criteria: bycatch, baitfish, invasive, vagrant, important for ecosystem energy transfer, and predators and prey of the above species. Using the dataset compiled for the 53 regional fishes and macroinvertebrates, we rank species (including for different lifestages) by their maximum thermal limit, as well as by the lowest oxygen concentration tolerated before negative impacts (e.g. physiological stress), 50% mortality or 100% mortality are experienced. Additionally, we compare these thresholds to observed marine deoxygenation trends at multiple sites, and observed surface warming trends. This results in an assessment of which regional species are most vulnerable to future warming and oxygen depletion, and a first-order estimate of the consequences of thermal and oxygen stress on a highly productive marine shelf. If regional multi-decadal oxygen and temperature trends continue through the 21st century, many species will lose favorable oxygen conditions, experience oxygen-stress, or disappear due to insufficient oxygen. Future warming can additionally displace vulnerable species, though we note that large natural variability in environmental conditions may amplify or dampen the effects of anthropogenic surface warming trends. This dataset may be combined with regional ocean model predictions to map future species distributions.

Brennan, Catherine E.; Blanchard, Hannah; Fennel, Katja

2014-05-01

193

Headwater locations of U.S. streams tributary to St. Lawrence River basin between western Ohio and eastern New York, excluding Lake Champlain basin  

USGS Publications Warehouse

The headwater locations of several thousand U.S. streams tributary to Lakes Ontario and Erie and the St. Lawrence and Niagara Rivers, from the Maumee River in Ohio to the western border of the Lake Champlain basin in New York, including parts of Pennsylvania, are listed by quadrangle. The location of the headwater of each is given with reference to cultural and topographic features. ' Headwater ' in this report is defined as the first site downstream from which the average streamflow is 5 cubic feet per second. The site locations were determined from drainage areas as indicated on topographic maps. The size of the drainage area required to produce an average flow of 5 cubic feet per second was determined from equations, developed separately for each State by regression techniques, that define the relation between streamflow and hydrologic factors of the region. Drainage area and precipitation were factors in the equations for all three States: forest cover was found to be significant in Ohio. (Woodard-USGS)

Eissler, Benjamin B.

1979-01-01

194

Detection of viral hemorrhagic septicemia in round gobies in New York State (USA) waters of Lake Ontario and the St. Lawrence River  

USGS Publications Warehouse

In May 2006 a large mortality of several thousand round gobies Neogobius melanostomus (Pallas, 1814) occurred in New York waters of the St. Lawrence River and Lake Ontario. Necropsies of sampled fish from these areas showed pallor of the liver and gills, and hemorrhagic areas in many organs. Histopathologic examination of affected tissues revealed areas of necrosis and hemorrhage. Inoculations of fathead minnow Pimephales promelas (Rafinesque, 1820) cell cultures with dilutions of tissue samples from the necropsied gobies produced a cytopathic effect within 5 d post-inoculation. Samples of cell culture supernatant were tested using RT-PCR and confirmed the presence of viral hemorrhagic septicemia virus (VHSV). Sequence analysis of the VHSV isolate resulted in its assignment to the type-IVb subgroup. The detection of VHSV in a relatively recent invasive fish species in the Great Lakes and the potential impact of VHSV on the ecology and economy of the area will require further investigation and careful management considerations. ?? Inter-Research 2007.

Groocock, G. H.; Getchell, R. G.; Wooster, G. A.; Britt, K. L.; Batts, W. N.; Winton, J. R.; Casey, R. N.; Casey, J. W.; Bowser, P. R.

2007-01-01

195

Influence of species and sex on metal residues in freshwater mussels (Family Unionidae) from the St. Lawrence River, with implications for biomonitoring programs  

SciTech Connect

The implementation of freshwater mussel watch programs has been hindered by a lack of information on biological factors affecting the levels of contaminants accumulated by these organisms. This study investigated the influence of species and sex on metal residues in Elliptio complanata and Lampsilis radiata radiata (Family Unionidae) from the St. Lawrence River. Mussels were collected from sites representing a wide range of types and degrees of metal pollution. Composite samples of five specimens (males and females combined) per species per site and five specimens per sex per species per site were analyzed for residues of 12 metals in the soft tissues to determine the effects of species and sex, respectively, on variability in the data. Interspecific differences in bioaccumulation were observed for most metals; however, concentrations were frequently correlated between species and the differences could therefore be quantified. Elliptio complanata demonstrated a broader response range to the same exposures than Lampsilis radiata radiata for most metals, suggesting that it may be more sensitive to changes in pollution status. Differences in metal uptake between the sexes were less pronounced than differences between species, and male specimens displayed less variability than females. Consideration of these factors in mussel biomonitoring programs should greatly improve sensitivity and precision.

Metcalfe-Smith, J.L. (Environment Canada, Burlington, Ontario (Canada). Rivers Research Branch)

1994-09-01

196

Speciation and transformation of phosphorus and its mixing behavior in the Bay of St. Louis estuary in the northern Gulf of Mexico  

NASA Astrophysics Data System (ADS)

Water samples were collected for measurements of dissolved, colloidal, and particulate inorganic and organic phosphorus (P) from the Bay of St. Louis estuary in the northern Gulf of Mexico during August 2008 and October 2009. Laboratory mixing experiments were also carried out using end-member river water and seawater to examine key processes and mechanisms controlling the behavior of P during estuarine mixing. Dissolved organic P (DOP) was the dominant species in the total dissolved P (TDP) pool in both lower (S < 10) and higher salinity (S > 25) regions, while dissolved inorganic P (DIP) predominated in mid-salinity regions (S of 10˜20) comprising up to 75% of the TDP. Both DIP and DOP behaved non-conservatively during estuarine mixing showing dramatic changes and transformation between different P species. The total particulate phosphorus (TPP) accounted for up to 85% of total phosphorus (TP = TDP + TPP) in the low-salinity areas but fell to about 38% in higher salinity regions. The quasi-negative correlation between TDP and TPP and the similarity in mixing behavior between field observations and laboratory experiments supported our hypothesis that physicochemical processes, such as dynamic repartitioning between water and particles or adsorption/desorption, are the predominant mechanisms controlling the biogeochemical cycling of P species in the Bay of St. Louis. River export fluxes of DIP could be significantly underestimated without the quantification of particulate P species, especially in more pristine river basins. The value of the distribution coefficient (in terms of logKd) ranged from 4.4 to 5.6 and decreased with increasing suspended particulate matter concentration and salinity, indicating that P is highly particle reactive and the presence of colloidal P may play an important role in the cycling of P in estuarine environments. Colloidal inorganic P (CIP) and colloidal organic P (COP), as quantified by an ultrafiltration permeation model, comprised 0-62% of the DIP and 34-93% of the DOP with the highest values in the river mouth area, suggesting a river source for colloidal P. The % CIP dropped to below the detection limit as salinity increased, whereas % COP first decreased but increased again with increasing salinity, reflecting different sources for CIP and COP in the lower estuary. The DOC/DOP ratio decreased rapidly with increasing salinity indicating a diagenetically older dissolved organic matter pool from the river and a dynamic change in sources and chemical speciation of P in the estuary.

Lin, Peng; Chen, Min; Guo, Laodong

2012-06-01

197

Meltwater discharge and the triggering of Younger Dryas : new data on the chronology of Champlain Sea transgression in the St-Lawrence River Valley  

NASA Astrophysics Data System (ADS)

Accurate chronology of ice retreat is crucial to understand the Ocean-Atmosphere couple at the end of the Pleistocene. The St-Lawrence River Valley is key in this regard, and two sedimentary sequences from Mount Saint-Hilaire, in the middle of the valley, contain a record that sheds new lignt on ice retreat and the penecontemporaneous proglacial marine invasion. Basal AMS-dates on terrestrial plant macrofossils coupled with an extrapolation from the pollen content of underlying postglacial lake sediments at Hemlock Carr (243 m), show that local ice retreat occurred around 11 350 14C yr BP. Cross-dating of such macrofossils (10 510 ± 60 14C yr BP) with shells from marine sediments (~12 200 14C yr BP) catched in the neighbouring Lake Hertel's basin (169 m) show a ca. 1700 14C years difference mainly ascribed to the effect of old, glacially-derived carbon in the upper shallow waters of the Champlain Sea. The pollen-based chronological extrapolation at Lake Hertel indicates that the marine invasion occurred around 11 100 ± 100 14C yr BP. This result supports the chronology based on deep-water invertebrate marine fauna (Rodrigues, 1988). The 14C assessment of the New-England varve chronology (Ridge et al., 1999) is thus confirmed. Deglaciation of the entire Saint-Lawrence River Valley took place within 1000 14C years. The chronology of ice retreat in southern Québec is shortened and made younger. This prompts major revision of all the associated paleohydrological events. Routing of the glacial meltwaters to the North Atlantic was impossible before 11 100 14C yr BP. The abrupt transition from Glacial Lake Candona (ca. 220 m) to the proglacial phase of the Champlain Sea (ca. 190 m) at 11 100 14C yr BP implies an input of glacial meltwater to the ocean estimated at 1500 km3. This may well have affected the thermohaline circulation in the North Atlantic and triggered the Younger Dryas oscillation.

Richard, P.; Occhietti, S.

2004-05-01

198

St  

Cancer.gov

St. Joseph’s/Candler, Savannah, Georgia Nancy N. and J.C. Lewis Cancer & Research Pavilion 5353 Reynolds Street Savannah, GA 31405 www.sjchs.org • Paul P. Hinchey, President and CEO, St. Joseph’s/Candler • Morris Geffen, MD, Principal Investigator/NCCCP

199

Annual dissolved nitrite plus nitrate and total phosphorous loads for the Susquehanna, St. Lawrence, Mississippi-Atchafalaya, and Columbia River basins, 1968-2004  

USGS Publications Warehouse

Annual stream-water loads were calculated near the outlet of four of the larger river basins (Susquehanna, St. Lawrence, Mississippi-Atchafalaya, and Columbia) in the United States for dissolved nitrite plus nitrate (NO2 + NO3) and total phosphorus using LOADEST load estimation software. Loads were estimated for the period 1968-2004; although loads estimated for individual river basins and chemical constituent combinations typically were for shorter time periods due to limitations in data availability. Stream discharge and water-quality data for load estimates were obtained from the U.S. Geological Survey (USGS) with additional stream discharge data for the Mississippi-Atchafalaya River Basin from the U.S. Army Corps of Engineers. The loads were estimated to support national assessments of changes in stream nutrient loads that are periodically conducted by Federal agencies (for example, U.S. Environmental Protection Agency) and other water- and land-resource organizations. Data, methods, and results of load estimates are summarized herein; including World Wide Web links to electronic ASCII text files containing the raw data. The load estimates are compared to dissolved NO2 + NO3 loads for three of the large river basins from 1971 to 1998 that the USGS provided during 2001 to The H. John Heinz III Center for Science, Economics and the Environment (The Heinz Center) for a report The Heinz Center published during 2002. Differences in the load estimates are the result of using the most up-to-date monitoring data since the 2001 analysis, differences in how concentrations less than the reporting limit were handled by the load estimation models, and some errors and exclusions in the 2001 analysis datasets (which resulted in some inaccurate load estimates).

Aulenbach, Brent T.

2006-01-01

200

Is the bone tissue of ring-billed gulls breeding in a pollution hotspot in the St. Lawrence River, Canada, impacted by halogenated flame retardant exposure?  

PubMed

Bone metabolism is a tightly regulated process that controls bone remodeling and repair in addition to maintaining circulating calcium and phosphate levels. It has been shown that certain organohalogen contaminants may adversely impact bone tissue metabolism and structure in wildlife species. However, exceedingly few studies have addressed the bone-related effects of organohalogen exposure in birds. The objective of the present study was to investigate the associations between markers of bone metabolism and structural integrity, and concentrations of established and current-use halogenated flame retardants (FRs) in ring-billed gulls (Larus delawarensis) nesting in a known FR hotspot area in the St. Lawrence River (Montreal, Canada). Bone metabolism was assessed using plasma calcium and inorganic phosphate levels, and alkaline phophatase activity, while bone (tarsus; trabecular and cortical sections) structure quality was examined using the percentage of bone tissue comprised in the total bone volume (Bv/Tv) and bone mineral density (BMD). Bv/Tv and BMD of the tarsus tended (not significant) to be positively associated with circulating calcium levels in male ring-billed gulls. Moreover, concentrations of FRs in male bird liver (brominated diphenyl ether (BDE)-154, -183, -201, and -209) and plasma (BDE-209) were negatively correlated with trabecular and cortical BMD of the tarsus. These correlative associations may suggest light demineralization of bone tissue associated with FR exposure in male ring-billed gulls. Present findings provide some evidence that bone (tarsus) metabolism and mineral composition may be impacted in high FR-exposed (mainly to PBDEs) ring-billed gulls breeding in the highly urbanized Montreal region. PMID:24016627

Plourde, Stéphanie Pellerin; Moreau, Robert; Letcher, Robert J; Verreault, Jonathan

2013-11-01

201

Fault stability and CO2 storage in the Early Paleozoic sedimentary basin of the St. Lawrence Lowlands (Quebec, Canada): insight from coupled reservoir-geomechanical modeling  

NASA Astrophysics Data System (ADS)

A coupled reservoir-geomechanical (TOUGH-FLAC) modeling is applied to evaluate the potential shear failure along pre-existing high-angle normal faults and tensile failure in the caprock units (Utica Shale and Lorraine Group) associated with CO2 injection into the sandstone reservoir (Covey Hill Formation) of the Early Paleozoic sedimentary basin in the St. Lawrence Lowlands (Quebec, Canada). Field and subsurface data are used to estimate sealing properties of the faults. The spatial variations in fluid pressure, effective minimum horizontal stress and shear strain are calculated for different injection rates using a simplified 2D geological model of the Becancour area between Montreal and Quebec City. The simulation results show that the likelihood of reactivating two reservoir-bounding faults (Yamaska and Champlain Faults) strongly depends on reservoir pressure at the faults, which in turn depends on injection rate, hydrological properties of aquifers and the distance between the faults and the injection well. The Yamaska Fault, which is located closer (1.5 km) to the injection zone is easier reactivated than the more distant (4.4 km) Champlain Fault. In addition, fault permeability affects the timing, localization, rate and length of fault shear slip. If the fault is sealing, shear slip occurs later in time and it is localized along the fault segment (230 m) below the caprock units. If the fault is permeable, the fault reactivation starts earlier and shear slip is nucleated along the fault segment (50 m) in the caprock units subsequently progressing up to the surface. Sealing fault behaviour causes asymmetric fluid pressure build-up and lateral migration of CO2 plume away from the closer-to-injection Yamaska fault that reduces the overall risk of CO2 leakage along faults. The fluid-pressure induced tensile fracturing postdates shear failure along faults; it occurs only under extremely high reservoir pressure as a result of high injection rates, with fracturing being localized below the caprock units, which remain intact preventing upward CO2 migration. Fig. 1. Changes in effective shear strain occurred around the injection zone and along the Yamaska Fault during subsequent steps of experimental run, low injection rate, sealing fault behaviour. Fault slip occurs after 22.5 years of continued injection.

Konstantinovskaya, E.; Rutqvist, J.; Malo, M.

2013-12-01

202

Estuary Live!  

NSDL National Science Digital Library

Classrooms and individuals can log on to participate in a real-time field trip to a National Estuary Research Reserve. Ask questions, view live video and still images, and learn about estuaries from experts. Topics range from geology to water quality, estuary plants and animals, and cultural heritage. Includes: references and lesson plans, classroom activities and teachers' guides. Archives of previous years are available, featuring sessions from East, West and Gulf Coast estuaries.

203

Exploring Estuaries  

NSDL National Science Digital Library

Defines estuaries and related habitats, reviews their roles in coastal ecology and in supporting human activities. Virtual tours provide history and introduce ecology of representative plans and animals. Presents current threats to estuaries and their wildlife and explains the role of EPA's National Estuary Program in protecting these important coastal resources. Includes: teachers' page with resources and links; games, coloring sheets and glossary for kids.

204

Exploring Estuaries  

NSDL National Science Digital Library

Exploring Estuaries introduces students of various ages to the ecology of estuaries, places where freshwater rivers and streams flow into the ocean, mixing with the seawater. It is part of a broader effort by the National Estuary Program to educate the general public about estuaries and to restore and protect these sensitive ecosystems. It offers interactive games and activities as well as virtual tours of Long Island Sound and the Barataria-Terrebonne Estuarine Complex near New Orleans. A glossary page defines technical terms used throughout the site. Resources also are provided for teachers and students interested in learning more about related organizations, publications, and websites.

205

Occurrence of alkylphenols and alkylphenol mono- and diethoxylates in natural waters of the Laurentian Great Lakes basin and the upper St. Lawrence River  

Microsoft Academic Search

Nonylphenol and its ethoxylates are on the second priority substances list (PSL2) to determine if they are ‘toxic’ as defined under the Canadian Environmental Protection Act. This study addresses the need for data on their occurrence in surface waters and sediments in Canada. Samples of surface water from 35 sites in the Laurentian Great Lakes basin and the upper St.

D. T. Bennie; C. A. Sullivan; H.-B. Lee; T. E. Peart; R. J. Maguire

1997-01-01

206

Environmental Baseline Studies of St. Marys River Near Neebish Island, Michigan, Prior to Proposed Extension of Navigation Season, 1981. Great Lakes-St. Lawrence Seaway, Navigation Season Extension Program.  

National Technical Information Service (NTIS)

The objective of this study was to expand existing biological, physical and chemical data for the St. Marys River to monitor possible environmental changes associated with winter navigation-related activities, such as icebreaking and winter ship movements...

C. D. McNabb C. R. Liston D. Ashton R. Ligman W. Duffy

1983-01-01

207

Water and sediment dynamics at Saint Lawrence River mouth  

Microsoft Academic Search

The main features of the hydrological regime and morphological structure of the estuarine-type mouth area of the Saint Lawrence\\u000a River are considered. Data on the structure of water masses, thermal and ice regimes in the Gulf of Saint Lawrence, which\\u000a has a significant effect on the estuary, are given. The major attention is paid to water mixing processes, water and

E. N. Dolgopolova; M. V. Isupova

2011-01-01

208

Common cyclicities in the seismicity and water level fluctuations at the charlevoix seismic zone on the St Lawrence River, Quebec, Canada  

NASA Astrophysics Data System (ADS)

Intraplate seismicity has no widely accepted explanation for its origin. The hydroseismicity hypothesis suggests that natural increases in hydraulic head, caused by transient increases in water table elevation, can be transmitted to hypocentral depths (10-25 km) in a fractured, prestressed, near-failure crust, and, along with long term hydrolytic weakening of rocks, contribute to the triggering of earthquakes. In this study, the temporal characteristics of seismicity and water level fluctuations at the Charlevoix seismic zone on the Saint Lawrence River in Quebec, Canada, are determined using Fourier spectral analysis and are investigated for possible temporal relationships, as predicted by hydroseismicity, using group delay analysis. Fourier spectral analysis of the temporal release of seismic energy indicates the presence of short term cyclicities of periods of 13-14 yr, along with longer term periods of approx. 55-70 yr. Spectral analysis of the water level data indicates cyclicities with periods of 1, 23, 14 and 8 years. Group delay analysis of the 14 yr periodicities in the water level and seismicity time series yields a time lag of 2.3-2.6 yr, with the water levels leading the seismicity time series. Crustal diffusivity values estimated from the group delay analysis range between 0.3 and 2.7 m 2/s, for a depth interval from 7 to 20 km, which is within the range of published values of diffusivities for the crust (0.1-100 m 2/sec). The present study suggests that common cyclicities are present in both the water levels and seismicity in the Charlevoix region. Such cyclicities are an essential element of the hydroseismicity hypothesis for the diffusion of surficial fluid pressure variations to hypocentral depths. Furthermore, the temporal relationship between the cyclicities observed allows for a possible causal relationship between repetitive mechanical effects of pore pressure transients and seismicity in the Charlevoix region.

Tsoflias, George P.; Bollinger, G. A.; Costain, John K.

1995-03-01

209

TRENDS IN SALINITIES AND FLUSHING TIMES OF GEORGIA ESTUARIES  

Microsoft Academic Search

From 1973-1992, the Georgia EPD sponsored a monitoring program in which surface salinities were sampled regularly at fixed stations in many of Georgia's estuaries. We used these data to examine changes in the salinities and flushing times of the Savannah, Ogeechee, Altamaha, Satilla, and St. Marys estuaries over the period of record. Water-year average salinities increased slightly over time in

Merryl Alber; Joan E. Sheldon

210

Classification of Estuaries  

NSDL National Science Digital Library

This text states that although all estuaries are similar in that they are semi-enclosed bodies of brackish water, they are categorized with regard to geological characteristics, and further distinguished on the basis of stratification and circulation patterns. According to their geological characteristics, estuaries are classified as: drowned river valleys or coastal-plain estuaries, bar-built estuaries or lagoons, fjord-type estuaries, and tectonically caused estuaries. Each type is explained in detail and examples are given for each.

211

Classification of Estuaries  

NSDL National Science Digital Library

This text states that although all estuaries are similar in that they are semi-enclosed bodies of brackish water, they are categorized with regard to geological characteristics, and further distinguished on the basis of stratification and circulation patterns. According to their geological characteristics, estuaries are classified as: drowned river valleys or coastal-plain estuaries, bar-built estuaries or lagoons, fjord-type estuaries, and tectonically caused estuaries. Each type is explained in detail and examples are given for each.

Oberrecht, Kenn

2007-01-30

212

Distribution, abundance, and range of the round goby, Apollina melanostoma, in the Duluth-Superior Harbor and St. Louis River estuary, 1998-2004  

USGS Publications Warehouse

Round gobies were first discovered in the Duluth-Superior Harbor, Lake Superior, in 1995. Anecdotal sightings by anglers and others suggested that the infestation was growing and expanding; however, direct evidence of the distribution and expansion rate in the harbor was largely unknown. Distribution and range of the round goby, Apollonia melanostoma, (formerly Neogobius melanostomus) was assessed using bottom trawl sampling throughout the Duluth-Superior Harbor, and portions of the lower St. Louis River from 1998 to 2004. Previous to 1998, round gobies only were reported to occupy the harbor between the two shipping entries (river kilometer 1 to 7). By 2004, they expanded throughout the harbor and upstream to river kilometer 13, but remained absent in western Lake Superior. The number of round gobies captured per 5 minutes of trawling (catch per unit effort, CPUE) increased from less than 1 fish in 1998 to an average 5.4 ?? 1.2 SE fish in 2004, indicating a large increase in the population. The median yearly fish total length varied from 56.0 to 81.5 mm and wet weight varied from 2.3 to 7.0 g. As nest guarding male round gobies were located in rocky habitats inaccessible to trawling, the initial years were dominated by female round gobies with a 16:1 female to male ratio, but by 2002 the maximum ratio was 2:1. The ratio change may be indicative of the increasing population forcing males from their preferred rocky habitat onto open substrates that were more accessible to trawling.

Bergstrom, M. A.; Evrard, L. M.; Mensinger, A. F.

2008-01-01

213

Saint Lawrence River--Past and Present. A Review of Historical Natural Resource Information and Habitat Changes in the International Section of the Saint Lawrence River.  

National Technical Information Service (NTIS)

This report provides a review of historical natural resource data and habitat changes in the international section of the St. Lawrence River. The report is keyed to both published and unpublished natural resource information and includes an extensive bibl...

P. P. Hamilton

1984-01-01

214

Welcome to Estuaries  

NSDL National Science Digital Library

This resource features three sections devoted to learning about estuaries: an online tutorial, an educational roadmap to resources, and formal lesson plans. The tutorial shows how estuaries are classified by their geology and water circulation patterns, the various ecosystem services estuaries perform, how organisms have adapted to the unique environmental conditions found in estuaries, the many disturbances that estuaries face from nature and human activities, and finally, the essential work that the National Estuarine Research Reserve System and its many partners conduct to monitor, preserve, and restore estuarine ecosystems throughout the United States. The roadmap to resources provides a set of links to specific data related to the information presented in the tutorial. Lesson plans on estuaries are also provided.

215

Linking Species Traits to the Abiotic Template of Flowing Waters: Contrasting Eco physiologies Underlie Displacement of Zebra Mussels by Quagga Mussels in a Large River-Estuary  

NASA Astrophysics Data System (ADS)

The St. Lawrence River-Estuary was the gateway of entry for dreissenids to North America and holds some of the oldest populations. The St. Lawrence also has four distinct physical-chemical water masses (a regional scale abiotic template) that both species inhabit. Despite their ecological similarities, quagga mussels are supplanting zebra mussels in much of their shared range. In order to try to better understand the changing distributions of these two species we compared glycogen, shell mass and tissue biomass in each of the water masses. This comparative physiological combined with experimental approaches (estuarine salinity experiments and reciprocal transplants) showed that while quagga mussels should dominate in most habitats, that abiotic/bioenergetic constraints in two regions (the Ottawa River plume and the freshwater-marine transition zone) might prevent them from dominating these locations. These findings are an example of how the interaction of landscape scale abiotic heterogeneity and a species-specific physiology can have strong impacts of distribution of biota large rivers.

Casper, A. F.

2005-05-01

216

Learning Lessons from Estuaries  

ERIC Educational Resources Information Center

There is something that draws all people to the sea and especially to the fertile estuaries that nuzzle up to its shores. An estuary serves as both a nursery and a grave for sea creatures. If life evolved from some primordial sea, it may well have been an estuary--a place where ocean and rivers meet and fresh and salty waters mingle in the…

Schnittka, Christine

2006-01-01

217

Regional Differences Among Estuaries  

NSDL National Science Digital Library

This text discusses differences in estuaries in different regions of the United States. It contrasts the fjord-like estuaries of the rocky Maine coast with the sandy barrier beaches, islands, and enclosed bays and sounds further south. The site also calls attention to the difference between the East Coast and the Northwest coast of emergence. The point is made that although they differ, all estuaries have great value and many are in danger.

Oberrecht, Kenn

2007-01-20

218

Regional Differences Among Estuaries  

NSDL National Science Digital Library

This text discusses differences in estuaries in different regions of the United States. It contrasts the fjord-like estuaries of the rocky Maine coast with the sandy barrier beaches, islands, and enclosed bays and sounds further south. The site also calls attention to the difference between the East Coast and the Northwest coast of emergence. The point is made that although they differ, all estuaries have great value and many are in danger.

219

2008\\u2029ICES\\u2029Annual\\u2029Science\\u2029Conference 22-26\\u2029September,\\u2029Halifax,\\u2029Nova\\u2029Scotia,\\u2029Canada . The\\u2029impact\\u2029of\\u2029hypoxia\\u2029on\\u2029cod\\u2029from\\u2029the\\u2029Baltic\\u2029and\\u2029 the\\u2029Gulf\\u2029of\\u2029St.\\u2029Lawrence  

Microsoft Academic Search

Both the Baltic Sea and the Gulf of St. Lawrence are characterised by low levels of dissolved oxygen (DO) below a halocline. When hydrographical conditions are favourable, salty oxygenated water from the North Sea flows into the deep basins of the Baltic. Between such events, oxygen levels are progressively depleted. During the last few decades, the frequency of inflows has

2008-01-01

220

Lawrence Hall of Science  

NSDL National Science Digital Library

Lawrence Hall of Science is a resource center for preschool through high school science and mathematics education, and a public science center with hands-on experiences for learners of all ages. Home of the William Knox Holt Planetarium, there is extensive educational programming centered on astronomy, including Planetarium Activities for Student Success kits for purchase that illustrate basic principles of astronomy. Earthquakes, erosion, wind and weather are the focus of the Forces that Shape the Bay exhibits, and there are also a number of exhibits highlighting math and physics. The website provides many online games and home activities available for download. The Lawrence Hall of Science Center for Curriculum Innovation creates instructional materials in mathematics and science for preschool through 12th graders for use by students, teachers and other educators, parents and families, and the website provides an array of information on the various programs. Title II funding for professional development is available.

221

DYNAMIC ESTUARY MODEL PERFORMANCE  

EPA Science Inventory

Applications of the Dynamic Estuary Model (DEM) to both the Delaware and Potomac Estuaries by the Environmental Protection Agency during the 1970s are summarized and evaluated. Methods for calibrating, refining, and validating this model, and statistics for evaluating its perform...

222

Biogeochemistry of Estuaries  

NASA Astrophysics Data System (ADS)

Whether you are interested in material flux from the continents to the oceans or whether the oysters set down in front of you at a waterfront restaurant may have come from polluted waters, we know estuaries are important places. However, anyone attempting to summarize and synthesize the long and rich literature of estuarine research is presented with a daunting task. This is because beyond the concept of an estuary being the transition zone where ``fresh water meets seawater,'' the exact definition of an estuary is not uniformly agreed upon by scientists in this field. Also, estuaries-regardless of how they are defined-tend to be highly heterogeneous, in both space and time. Against this backdrop, Thomas Bianchi's Biogeochemistry of Estuaries successfully tackles its subject matter and is an exciting addition to the field of estuarine research.

Burdige, David J.

2007-12-01

223

Aging and sediment characteristics of northern Gulf of Mexico estuaries  

Microsoft Academic Search

Eight major estuarine systems present along the northern margin of the Gulf of Mexico serve as primary depositional basins for all rivers draining into the gulf from central Louisiana eastward to the Florida peninsula. These estuaries consist of Apalachicola Bay, St. Andrews Bay, Choctawhatchee Bay, Pensacola Bay, Perdido Bay, Mobile Bay, Mississippi sound, and Lake Pontchartrainn. Because each receives sediment

W. C. Isphording; F. D. Imsand; G. C. Flowers

1989-01-01

224

Sex alteration in soft-shell clams ( Mya arenaria) in an intertidal zone of the Saint Lawrence River (Quebec, Canada)  

Microsoft Academic Search

The purpose of this study was to verify whether any changes in sex ratio might occur in soft-shell clams (Mya arenaria) located in an intertidal harbor zone located at the mouth of the Saguenay Fjord in the Saint Lawrence estuary (Baie Sainte-Catherine (BSC), Québec, Canada) likely to be contaminated by organotin compounds. Bivalves were harvested at the BSC harbor site

F Gagné; C Blaise; J Pellerin; E Pelletier; M Douville; S Gauthier-Clerc; L Viglino

2003-01-01

225

Learning Lessons from Estuaries  

NSDL National Science Digital Library

There is something that draws us all to the sea and especially to the fertile estuaries that nuzzle up to its shores. An estuary serves as both a nursery and a grave for sea creatures. This article describes annual trips to three islands in the Chesapeake Bay and the long-term impact these trips have had on students. Although the activities described in this article are centered around the Bay, this example of an immersive field experience could be duplicated in other ecosystems around the country (see "On the web" at the end of this article for information on planning an estuary field trip).

Schnittka, Christine

2006-01-01

226

Coagulation in Estuaries.  

National Technical Information Service (NTIS)

The coagulation rates of kaolinite, illite, and montmorillonite were determined in solutions at various ionic strengths. In addition, the coagulation rates of selected sediments collected from the Pamlico Estuary of North Carolina were determined. Finally...

J. K. Edzwald

1972-01-01

227

Lawrence Denny Lindsley Photographs  

NSDL National Science Digital Library

Lawrence Denny Lindsley was born in 1878 in a house on scenic Lake Union, right in the middle of the relatively young city of Seattle, Washington. As a descendant of the early Seattle pioneer David Denny, Lindsley began to wander around the city and its environs from a young age. Like many men in the Pacific Northwest during the late 19th century, he enjoyed the outdoors, and soon developed a skill for photography. He later went on to work for Edward Curtis, and he continued on by documenting such landscapes as Mount Rainer, Lake Chelan, and the Olympic Peninsula. Many of these excellent photographs can be viewed in this latest offering from the University of Washington Libraries Digital Collection. All told, there are 472 photographs here, complete with detailed records. The King County section is a real highlight, as visitors will get a real sense of the area before it became heavily urbanized during the 20th century.

2006-01-01

228

Decline of Canada geese (Branta canadensis) and common goldeneye (Bucephala clangula) associated with a collapse of eelgrass (Zostera marina) in a Nova Scotia estuary  

NASA Astrophysics Data System (ADS)

Mean numbers of migrant Canada geese (Branta canadensis) in Antigonish Harbour in the southern Gulf of St. Lawrence (Canada) during October to December were similar (approx. 450-500 birds) for the period 1998-2000. Similarly, during this period, geese used two foraging sites. However, in 2001, the average number of birds decreased by half and the primary foraging sites were used only rarely. This coincided with a decline of about 95% in the biomass of roots and rhizomes of eelgrass (Zostera marina) that occurred between October 2000 and 2001. Eelgrass is the principal food of geese in this estuary. In addition, there was a reduction of around 50% in the numbers of common goldeneye (Bucephala clangula), which feed on invertebrates associated with eelgrass. Lower than usual weekly abundances of geese and goldeneye are probably the result of an unusually short residence time in the estuary, rather than a decline in the total number of visiting migrants. We attribute these changes in the distribution and abundance of geese and goldeneyes to the dramatic decline in eelgrass.

Seymour, Norman; Miller, Anthony; Garbary, David

2002-08-01

229

Restore America's Estuaries  

NSDL National Science Digital Library

This non-profit organization promotes the restoration and protection of America's estuaries. Projects encompass scientific research, education and community-based action, including restoration by school youngsters, as well as policy initiatives at the national level. An introduction to estuaries contains concise definitions, value in ecology and economics, current threats, and elements of restoration. Also offers: links to educational resources; news and photo gallery; a CD-rom guide to estuarine restoration.

230

Volunteer Estuary Monitoring  

NSDL National Science Digital Library

This online method manual from EPA describes how to conduct estuary monitoring programs, with step-by-step guides for chemical, physical and biological sampling and data interpretation. Also describes how to plan and maintain a volunteer force, with tips on liability and financial issues, volunteer recruiting training and retention. Addresses quality assurance so that results have weight. Provides an overview of estuarine science, threats to estuaries and some solutions.

231

Estuarine Science: All About Estuaries  

NSDL National Science Digital Library

Estuaries are partially enclosed bodies of water along coastlines where fresh water and salt water meet and mix. They act as a transition zone between oceans and continents. This site examines various aspects of estuaries, focusing on the geological features that make an estuary, as well as the water circulation patterns by which they are classified. It also has a section that allows the user to access additional text and graphics on many of the estuaries of the world.

232

Lawrence Berkeley National Laboratory  

NSDL National Science Digital Library

Arguably the most famous government research laboratory in the United States, the Lawrence Berkeley National Laboratory is supported by the U.S. Department of Energy and managed by the University of California. Scientists associated with the laboratory have received a number of accolades over the years, including 13 Nobel Prizes and 13 National Medals of Science. The materials on the site are divided into five primary sections, including About the Lab, For Staff and Guests, and Visitor's Guide. First-time users may wish to start with the News Center. Here they can read press releases and features, and watch videos of scientists talking about their work. The Video Glossary contains wonderful clips of scientists talking about atmospheric aerosols, energy efficiency, and myriad other topics. The general public won't want to miss the "$ Ways to Save Money on Energy" section and the equally compelling area on Globally Transformative Technologies. The site is rounded out by a place where visitors can follow the Laboratory's activities via Facebook, Twitter, and YouTube.

233

THREE-DIMENSIONAL MODELING OF COHESIVE SEDIMENT TRANSPORT IN A PARTIALLY STRATIFIED MICRO-TIDAL ESTUARY TO ASSESS EFFECTIVENESS OF SEDIMENT TRAPS  

EPA Science Inventory

The three-dimensional (3D) finite difference model Environmental Fluid Dynamics Code (EFDC) was used to simulate the hydrodynamics and sediment transport in a partially stratified micro-tidal estuary. The estuary modeled consisted of a 16-km reach of the St. Johns River, Florida,...

234

The Trouble at Sarah Lawrence  

ERIC Educational Resources Information Center

The emergence of homosexuality as a professedly viable alternative is seen as a byproduct of the basic problem at Sarah Lawrence. That is the conflict between the women's movement on campus and the administration's efforts to proceed to full coeducation. (LBH)

Roiphe, Anne

1977-01-01

235

A detailed magnetic survey of the Saint Lawrence River: Oak Point to Lake Ontario, New York  

Microsoft Academic Search

Measurements of the total intensity of the Earth's magnetic field in the St. Lawrence River between Oak Point and Lake Ontario indicated magnetic anomalies of high magnitude and steep gradients due to rocks of varying magnetic susceptibility in the Precambrian basement complex. The anomalies and magnetic contours that trend continuously across the river indicated no large lateral offset in this

F. Revetta; J. Cardinal

1979-01-01

236

Organotins in Zebra Mussels ( Dreissena polymorpha) from the Saint Lawrence River  

Microsoft Academic Search

Toxic antifouling compounds such as organotins have been released in the aquatic ecosystems throughout the world and can be bioaccumulating in biota. The purpose of this study was to assess the use of zebra mussels (Dreissena polymorpha) as a biomonitor for investigating the geographical variations of organotin bioavailability along the St. Lawrence River. The presence of organotins (tributyltins (TBT) and

Lidia Regoli; Hing Man Chan; Yves de Lafontaine

1999-01-01

237

75 FR 34975 - Notice of Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration...  

Federal Register 2010, 2011, 2012, 2013

...0648-XX00 Notice of Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration Strategy; Request for Public Comment...behalf of the interagency Estuary Habitat Restoration Council, is providing notice of...

2010-06-21

238

Catch characteristics of the commercial beach-seine fisheries in two Australian barrier estuaries  

Microsoft Academic Search

A scientific observer programme was used to estimate the retained and discarded catches taken in two of the largest commercial beach-seine fisheries (Lake Macquarie and St. Georges Basin) in New South Wales, Australia. Catches were sampled in each estuary in each of four seasons throughout 1998\\/1999 and the data were used to estimate the quantities and length compositions of species

Charles A. Gray; Steven J. Kennelly

2003-01-01

239

Lawrence Berkeley National Laboratory: VISTA  

NSDL National Science Digital Library

A very comprehensive and well-organized offering from Lawrence Berkeley National Laboratory, VISTA offers "suite of programs and databases for comparative analysis of genomic sequences. There are two ways of using VISTA - you can submit your own sequences and alignments for analysis (VISTA servers) or examine pre-computed whole-genome alignments of different species (VISTA browser)." The site also offers up-to-date updates on genomic sequences. Included in the April 2004 update are the Human-Chimpanzee, Human-Chicken, and D.melanogaster-Honey Bee whole genome alignments. VISTA is definitely a site for researchers and students involved in genomic research.

2008-04-14

240

Lawrence Berkeley National Laboratory: VISTA  

NSDL National Science Digital Library

A very comprehensive and well-organized offering from Lawrence Berkeley National Laboratory, VISTA offers "suite of programs and databases for comparative analysis of genomic sequences. There are two ways of using VISTA - you can submit your own sequences and alignments for analysis (VISTA servers) or examine pre-computed whole-genome alignments of different species (VISTA browser)." The site also offers up-to-date updates on genomic sequences. Included in the April 2004 update are the Human-Chimpanzee, Human-Chicken, and D.melanogaster-Honey Bee whole genome alignments. VISTA is definitely a site for researchers and students involved in genomic research.

241

Great Bay Estuary Restoration Compendium.  

National Technical Information Service (NTIS)

Single species approaches to natural resource conservation and management are now viewed as antiquated and oversimplified for dealing with complex systems. Scientists and managers who work in estuaries and other marine systems have urged adoption of ecosy...

A. Eberhardt D. Burdick J. Odell P. Ingraham

2006-01-01

242

Lawrence Livermore National Laboratory 2007 Annual Report  

SciTech Connect

Lawrence Livermore National Laboratory's many outstanding accomplishments in 2007 are a tribute to a dedicated staff, which is shaping the Laboratory's future as we go through a period of transition and transformation. The achievements highlighted in this annual report illustrate our focus on the important problems that affect our nation's security and global stability, our application of breakthrough science and technology to tackle those problems, and our commitment to safe, secure, and efficient operations. In May 2007, the Department of Energy (DOE) awarded Lawrence Livermore National Security, LLC (LLNS), a new public-private partnership, the contract to manage and operate the Laboratory starting in October. Since its inception in 1952, the Laboratory had been managed by the University of California (UC) for the DOE's National Nuclear Security Administration (NNSA) and predecessor organizations. UC is one of the parent organizations that make up LLNS, and UC's presence in the new management entity will help us carry forward our strong tradition of multidisciplinary science and technology. 'Team science' applied to big problems was pioneered by the Laboratory's co-founder and namesake, Ernest O. Lawrence, and has been our hallmark ever since. Transition began fully a year before DOE's announcement. More than 1,600 activities had to be carried out to transition the Laboratory from management by a not-for-profit to a private entity. People, property, and procedures as well as contracts, formal agreements, and liabilities had to be transferred to LLNS. The pre-transition and transition teams did a superb job, and I thank them for their hard work. Transformation is an ongoing process at Livermore. We continually reinvent ourselves as we seek breakthroughs that impact emerging national needs. An example is our development in the late 1990s of a portable instrument that could rapidly detect DNA signatures, research that started with a view toward the potential threat of terrorist use of biological weapons. As featured in our annual report, activities in this area have grown to many important projects contributing to homeland security and disease prevention and control. At times transformation happens in large steps. Such was the case when nuclear testing stopped in the early 1990s. As one of the nation's nuclear weapon design laboratories, Livermore embarked on the Stockpile Stewardship Program. The objectives are to ensure the safety, security, and reliability of the nation's nuclear weapons stockpile and to develop a science-based, thorough understanding of the performance of nuclear weapons. The ultimate goal is to sustain confidence in an aging stockpile without nuclear testing. Now is another time of major change for the Laboratory as the nation is resizing its nuclear deterrent and NNSA begins taking steps to transform the nuclear weapons complex to meet 21st-century national security needs. As you will notice in the opening commentary to each section of this report, the Laboratory's senior management team is a mixture of new and familiar faces. LLNS drew the best talent from its parent organizations--Bechtel National, UC, Babcock & Wilcox, the Washington Group Division of URS, and Battelle--to lead the Laboratory. We are honored to take on the responsibility and see a future with great opportunities for Livermore to apply its exceptional science and technology to important national problems. We will work with NNSA to build on the successful Stockpile Stewardship Program and transform the nation's nuclear weapons complex to become smaller, safer, more secure, and more cost effective. Our annual report highlights progress in many relevant areas. Laboratory scientists are using astonishing computational capabilities--including BlueGene/L, the world's fastest supercomputer with a revolutionary architecture and over 200,000 processors--to gain key insights about performance of aging nuclear weapons. What we learn will help us sustain the stockpile without nuclear testing. Preparations are underway to start experiments at

Chrzanowski, P; Walter, K

2008-04-25

243

Dissolved oxygen in two Oregon estuaries: The importance of the ocean-estuary connection  

EPA Science Inventory

We examined the role of the ocean ?estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO ...

244

Dissolved oxygen in two Oregon estuaries: Importance of the ocean-estuary connection - March 2011  

EPA Science Inventory

We examined the role of the ocean?estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO w...

245

Dissolved oxygen in two Oregon estuaries: Importance of the ocean-estuary connection  

EPA Science Inventory

We examined the role of the ocean ?estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO ...

246

PECONIC ESTUARY EELGRASS HABITAT CRITERIA STUDY  

EPA Science Inventory

PECONIC ESTUARY EELGRASS HABITAT CRITERIA STUDY The main objective of this study is to develop criteria for eelgrass habitat establishment and persistence within the Peconic Estuary utilizing various environmental analyses. The Program evaluated water and sediment quality data to...

247

Nitrogen Budget of a North Carolina Estuary.  

National Technical Information Service (NTIS)

The Pamlico River estuary of eastern North Carolina is a relatively oligotrophic ecosystem which is entering the initial stages of cultural eutrophication. The estuary is naturally rich in phosphorus and indirect evidence indicates that nitrogen probably ...

W. G. Harrison J. E. Hobbie

1974-01-01

248

Estuaries and Clean Water Act of 2000  

NSDL National Science Digital Library

The Office of Water at the Environmental Protection Agency has posted online this document on the new Estuaries and Clean Water Act of 2000. Available in .pdf format, the document summarizes the Act, which emphasizes restoration of estuary habitat.

249

Lawrence Livermore National Laboratory: Nanoscience  

NSDL National Science Digital Library

Lawrence Livermore National LaboratoryâÂÂs nanotechnology programs focus on issues relevant to national security. Lab researchers âÂÂdrive the future of homeland security through innovations in biosensing and radiation detector materials, chemical absorbants, and biofunctional materialsâ and other materials research. The website divides their work into three main areas: Bionanoscience, Nanofabrication, and Theory, Simulation, and Modeling. The website includes a brief description of each research area and links to related articles. The section on Bionanoscience includes links to journal publications, most of which require a paid subscription. Links to various laboratories housed within LLNL highlight additional contributions and research programs from those labs as well as information on their educational programs.

250

LAWRENCE RISK-BASED AIR SCREENING  

EPA Science Inventory

The pediatric asthma rate in the city of Lawrence is the highest in the state of Massachusetts. This project will evaluate whether the cumulative risks due to the air pollution in Lawrence is contributing to the high asthma rates and other respiratory problems. The project will...

251

Estuaries: Where Rivers Meet the Sea  

NSDL National Science Digital Library

Take your students on an EstuaryLive telecast! EstuaryLive brings free, live internet field trips in four different estuaries around the country, right to your classroom. These online field trips are the next best thing to an actual trip to an estuary, providing students with an exciting and new way to learn about unique estuarine ecosystems. The site also includes archived webcasts and teacher resources including classroom activities and a glossary.

252

Estuaries: Where Rivers Meet the Sea  

NSDL National Science Digital Library

Take your students on an EstuaryLive telecast! EstuaryLive brings free, live internet field trips in four different estuaries around the country, right to your classroom. These online field trips are the next best thing to an actual trip to an estuary, providing students with an exciting and new way to learn about unique estuarine ecosystems. The site also includes archived webcasts and teacher resources including classroom activities and a glossary.

2011-05-16

253

14. Historic American Buildings Survey PHOTOCOPY OF EVERETT MILLS, LAWRENCE, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. Historic American Buildings Survey PHOTOCOPY OF EVERETT MILLS, LAWRENCE, MASS., INSURANCE SURVEY DRAWING n. d. From the collection of Factory Mutual Insurance Company, Norwood, Mass. - Lawrence Machine Shop, Union & Canal Streets, Lawrence, Essex County, MA

254

Monthly water balance in tributary watersheds of the Great Lakes Saint Lawrence River basin as influenced by climatic factors  

Microsoft Academic Search

SUMMARY: We observe in this basin the variation of the climate from pure oceanic at the Atlantic shores to continental at the west shores of Lake Michigan and the west extremity of Lake Superior. The type of hydrology generated by tributaries to the Great Lakes and to the St. Lawrence River is Lhe product of the climate dominating the tributary

Boris S. Browzin

255

DELAWARE ESTUARY A MANAGEMENT PLAN FOR THE DELAWARE ESTUARY  

EPA Science Inventory

Wise conservation and management of the Delaware Estuary is arguably the most important cooperative environmental initiative ever jointly undertaken by the States of New Jersey, Pennsylvania, and Delaware. While much has been accomplished over the past few decades to improve wate...

256

Saint Lawrence River Ice Boom Modification Study.  

National Technical Information Service (NTIS)

The objective of this study was to prepare designs and specifications for improvements to existing ice booms in the international portion of the Saint Lawrence River to allow extended season navigation through 31 December of each year. The study involved ...

J. W. Lewis D. L. Benze R. A. Etzel

1979-01-01

257

Lawrence Berkeley Laboratory Affirmative Action Program. Revised.  

National Technical Information Service (NTIS)

The Lawrence Berkeley Laboratory's Affirmative Action Program (AAP) serves as a working document that describes current policies, practices, and results in the area of affirmative action. It represents the Laboratory's framework for n affirmative approach...

1995-01-01

258

LAKE PONTCHARTRAIN ESTUARY CONSERVATION PLAN  

EPA Science Inventory

The Nature Conservancy will conduct a series of a least four science expert workshops to develop a Site Conservation Plan for the Lake Pontchartrain Estuary and adjacent wetlands. The objective of the Site Conservation Plan is to identify conservation targets, threats or stresse...

259

The Value of Healthy Estuaries  

NSDL National Science Digital Library

The article explores why healthy estuaries are critical to humans and wildlife: supporting both commercial and recreational fisheries, treating waste and runoff, protecting coastal areas from natural hazards, connect bodies of water for transportation, and nurturing a balance of the food web

Robert Christian (East Carolina University;)

2009-03-15

260

St. Louis  

Cancer.gov

The Psychology Department of St. Louis Children’s Hospital at Washington University Medical Center is pleased to recruit for a second Postdoctoral Fellowship position in Pediatric Psychology beginning September 2014. With a balance of in-depth and broad based training experiences, this one-year program will prepare fellows to work independently in the practice of pediatric psychology.

261

Historical morphological change in the Mersey Estuary  

NASA Astrophysics Data System (ADS)

Several techniques including analysis of bathymetric data, calculation of analytical parameters and computational hydrodynamic simulations are combined in this study to develop a conceptual understanding of processes causing morphological change in the Mersey Estuary between 1871 and 1997. Volumetric analysis demonstrates that morphological change is dominated by a trend of significant accretion between 1906 and 1977, with estuary volume reducing by ?10% (70 Mm3), followed by a relatively small increase in volume between 1977 and 1997. Previous research identified the construction of training walls between 1906 and 1936 to stabilise the position of the low water channel in Liverpool Bay outside the estuary as a probable cause of perturbation. The paper examines the hypothesis that sedimentation in the estuary was controlled by changes to hydrodynamic flow and related sediment transport patterns outside the estuary resulting from training wall construction, and that the estuary has now evolved towards a stable state. The results from computational hydrodynamic models for the years 1906, 1936 and 1977 quantifying potential changes in sediment transport pathways from outside the estuary indicate a significant increase in potential sediment supply to the mouth of the estuary during the period of peak accretion. However, these changes cannot be solely attributed to construction of the training walls, but result from the combined effect of training wall construction and dredging activity in the sea approach channels. Furthermore, it is not simply changes in hydrodynamic flow characteristics that cause sedimentation but also the existence of salinity-induced gravitational circulation within the estuary and wider Liverpool Bay system that acts as an important mechanism for importing sediment into the estuary. Evidence for evolution towards a stable estuary state is provided by derivation of a sediment budget demonstrating a negligible net flux of sediment into the estuary between 1977 and 1997. The establishment of a stable state is attributed to a reduction in the calculated transport of sediment across Liverpool Bay reducing the supply of sediment to the estuary mouth.

Thomas, C. G.; Spearman, J. R.; Turnbull, M. J.

2002-07-01

262

Comparison of Nutrient Drivers and Response Metrics in Oregon Estuaries  

EPA Science Inventory

With the goal of assessing sensitivity to nutrient enrichment, we present a cross-estuary comparison of nutrient sources, levels, and biological responses (phytoplankton and macroalgae) for thirteen Oregon estuaries. Nitrogen levels in the upstream portions of the estuaries are ...

263

MAPPING BATHYMETRY AND BOTTOM TYPE IN A SHALLOW ESTUARY  

EPA Science Inventory

Bathymetry and bottom type are important in characterizing estuaries and their ecology but hard to map, especially in shallow estuaries. Acoustic backscattering was used to remotely sense these properties in the shallow Slocums River Estuary of Massachusetts. Acoustic pulses were...

264

St. Lucia.  

PubMed

The population of St Lucia was 123,000 in 1986, with an annual growth rate of 2%. The infant mortality rate stands at 22.2/1000 live births, and life expectancy is 70.3 years for males and 74.9 years for females. The literacy rate is 78%. St Lucia's labor force is allocated as follows: agriculture, 36.6%; industry and commerce, 20.1%; and services, 18.1%. The gross national product (GNP) was US$146 million in 1985, with an annual growth rate of 3% and a per capita GNP of $1071. St Lucia is a parliamentary democracy modeled on the British Westminster system. The island is divided into 16 parishes and 1 urban area (the capital, Castries). St Lucia is currently a politically stable country, although the high level of youth unemployment is a cause for concern. Ongoing stability may depend on the government's ability to provide services such as jobs and housing. The economy has evolved from a monocrop sugar plantation type to a diversified economy based on agriculture, industry, and tourism. Agriculture, dominated by the banana industry, is characterized by the participation of a large number of small and medium-sized enterprises. Industry is being encouraged through the provision of incentives such as tax rebates. The government is attempting to maintain a sound investment climate through a tripartite dialogue with the private sector and trade unions. Overall economic policy is predicated on the attraction of sound investments, by both local and foreign entities, to accelerate the rate of economic growth, solve the unemployment problem, and generate a solid balance-of-payments position. PMID:12177918

1987-06-01

265

Morphodynamic equilibrium of alluvial estuaries  

NASA Astrophysics Data System (ADS)

The evolution of the longitudinal bed profile of an estuary, with given plan-form configuration, subject to given tidal forcing at the mouth and prescribed values of water and sediment supply from the river is investigated numerically. Our main goal is to ascertain whether, starting from some initial condition, the bed evolution tends to reach a unique equilibrium configuration asymptotically in time. Also, we investigate the morphological response of an alluvial estuary to changes in the tidal range and hydrologic forcing (flow and sediment supply). Finally, the solution helps characterizing the transition between the fluvially dominated region and the tidally dominated region of the estuary. All these issues play an important role also in interpreting how the facies changes along the estuary, thus helping to make correct paleo-environmental and sequence-stratigraphic interpretations of sedimentary successions (Dalrymple and Choi, 2007). Results show that the model is able to describe a wide class of settings ranging from tidally dominated estuaries to fluvially dominated estuaries. In the latter case, the solution is found to compare satisfactory with the analytical asymptotic solution recently derived by Seminara et al. (2012), under the hypothesis of fairly 'small' tidal oscillations. Simulations indicate that the system always moves toward an equilibrium configuration in which the net sediment flux in a tidal cycle is constant throughout the estuary and equal to the constant sediment flux discharged from the river. For constant width, the bed equilibrium profile of the estuarine channel is characterized by two distinct regions: a steeper reach seaward, dominated by the tide, and a less steep upstream reach, dominated by the river and characterized by the undisturbed bed slope. Although the latter reach, at equilibrium, is not directly affected by the tidal wave, however starting from an initial uniform stream with the constant 'fluvial' slope, the final equilibrium state is reached through an erosional wave, which leads to bed degradation of the upstream 'fluvial reach'. For a given river discharge, the length of the tidal reach increases quite rapidly with tidal amplitude, up to some threshold value of the tidal amplitude above which the length of the estuary becomes comparable with the length of the tidal wave. When the channel plan-form is convergent, deposition of sediments of fluvial origin in the funnel-shaped region drastically changes the equilibrium configuration. The effect of an increasing channel convergence is thus to induce bed aggradation close to the inlet. Nevertheless, tidal forcing only slightly changes the non-tidal profile. The effect of increasing tidal oscillations again leads to an increase of the bed slope at the inlet and to a general bed degradation upstream. The effects of varying sediment supply, flow discharge and river width in the upstream reach have also been investigated and play an important role. Further geomorphological implications of these results will be discussed at the meeting. References Dalrymple, R. W., and K. Choi (2007), Morphologic and facies trends through the fluvialmarine transition in tide-dominated depositional systems: A schematic framework for environmental and sequence-stratigraphic interpretation, Earth-Science Reviews, 81(3-4), 135-174, doi:10.1016/j.earscirev.2006.10.002. Seminara, G., M. Bolla Pittaluga, and N. Tambroni (2012), Morphodynamic equilibrium of tidal channels, Environmental Fluid Mechanics: Memorial Volume in Honour of Prof. Gerhard H. Jirka, 153-174

Tambroni, Nicoletta; Bolla Pittaluga, Michele; Canestrelli, Alberto; Lanzoni, Stefano; Seminara, Giovanni

2014-05-01

266

The Propagation of Tides up Rivers With Special Considerations on the Upper Saint Lawrence River  

NASA Astrophysics Data System (ADS)

The hydrodynamics of rivers affected by tides is dominated by the damping and the distortion induced by quadratic bottom friction. A compact and accurate approximation to the deceleration term, standing for the frictional effect, allows the retention of the concept of harmonics and separation of the time and space variations. It then becomes possible to explain, in terms of basic physics, the transformation of the tide from the estuary, to the zone where it becomes extinct. The theoretical reasoning is supported by pertinent observations collected in the Saint Lawrence river; numerical relations are derived to demonstrate the existence of non-linear effects and to quantitatively link various relevant physical parameters. This analysis, in turn, helps outline approaches to improve the tide predictions in such rivers which happen to have such great economic and strategic importance.

Godin, G.

1999-03-01

267

A theoretical framework for analyzing the effect of external change on tidal dynamics in estuaries  

NASA Astrophysics Data System (ADS)

The most densely populated areas of the world are usually located in coastal areas near estuaries. As a result, estuaries are often subject to intense human interventions, such as dredging for navigation, dam construction and fresh water withdrawal etc., which in some areas has led to serious deterioration of invaluable ecosystems. Hence it is important to understand the influence of such interventions on tidal dynamics in these areas. In this study, we present one consistent theoretical framework for tidal hydrodynamics, which can be used as a rapid assessment technique that assist policy maker and managers to make considered decisions for the protection and management of estuarine environment when assessing the effect of human interventions in estuaries. Analytical solutions to the one-dimensional St. Venant equations for the tidal hydrodynamics in convergent unbounded estuaries with negligible river discharge can be cast in the form of a set of four implicit dimensionless equations for phase lag, velocity amplitude, damping, and wave celerity, as a function of two localized parameters describing friction and convergence. This method allows for the comparison of the different analytical approaches by rewriting the different solutions in the same format. In this study, classical and more recent formulations are compared, showing the differences and similarities associated to their specific simplifications. The envelope method, which is based on the consideration of the dynamics at high water and low water, can be used to derive damping equations that use different friction approximations. This results in as many analytical solutions, and thereby allows one to build a consistent theoretical framework. Analysis of the asymptotic behaviour of the equations shows that an equilibrium tidal amplitude exits reflecting the balance between friction and channel convergence. The framework is subsequently extended to take into account the effect of river discharge. Hence, the analytical solutions are applicable even in the upstream part of an estuary, where the influence of river discharge is remarkable. The proposed analytical solutions are transparent and practical, allowing a quantitative and qualitative assessment of human interventions (e.g., dredging, flow reduction) on tidal dynamics. Moreover, they are rapid assessment techniques that enable the users to set up a simple model and to understand the functioning of the system with a minimum of information required. The analytical model is illustrated in three large-scale estuaries with significant influence by human activities, i.e., the Scheldt estuary in the Netherlands, the Modaomen and the Yangtze estuaries in China. In these estuaries, the correspondence with observations is good, which suggests that the proposed model is a useful, yet realistic and reliable instrument for quick detection of the effect of human interventions on tidal dynamics and subsequent environmental issues, such as salt intrusion.

CAI, H.; Savenije, H.; Toffolon, M.

2013-12-01

268

AFS Estuaries Section - A Successful Partnership  

EPA Science Inventory

The Estuaries Section of the American Fisheries Society offers travel awards to students in support of their attendance and presentations at the AFS meeting. Since 2007, the Southern Association of Marine Laboratories has partnered with the Estuaries Section to sponsor two stude...

269

NEW HAMPSHIRE'S ESTUARIES, THE STATE OF  

EPA Science Inventory

The State of the New Hampshire Estuary Report describes the region's valuable natural resources, explains how natural resources are linked to the cultural and economic well being of New Hampshire, and identifies threats to these resources. This State of the Estuaries Report summa...

270

NEW HAMPSHIRE ESTUARIES PROJECT MANAGEMENT PLAN, 2000  

EPA Science Inventory

The Comprehensive Conservation and Management Plan of the New Hampshire Estuaries Project presents a broad framework and specific list of actions to protect and enhance the environmental quality of the estuaries of the State of New Hampshire. It is intended to be a guide for all ...

271

A Climate Ready Estuaries Vulnerability Assessment  

EPA Science Inventory

The purpose of the the Climate Ready Estuaries program is to build capacity in the National Estuary Programs (NEPs) for local leadership and expertise to adapt to the effects of climate change through a joint effort with the NEPs and EPA. Background The Climate Ready...

272

Critical erosion profiles in macro-tidal estuary sediments: Implications for the stability of intertidal mud and the slope of mud banks  

NASA Astrophysics Data System (ADS)

Vertical profiles of the critical erosion threshold ( ?crit) in sediment have been measured at 11 stations along the axis of the Tamar Estuary and at a single station in a tributary of the Tamar at St. John's Ford. The ?crit of surface sediment increased from 0.04 Pa in the upper, brackish estuary to 0.09 Pa in the lower estuary. In the upper estuary ?crit only increased slightly with depth whereas in the marine estuary ?crit increased rapidly from 0.09 Pa at the surface to 0.25 Pa at 15 cm below the sediment surface. The results showed that the relationship between ?crit and bulk density ( ?b) obtained previously for surface sediment was also applicable to sediments from depths of 10-15 cm and probably deeper. Profiles of ?b were measured to depths of 70 cm using a corer. In the lower (marine) estuary ?b increased with depth in the sediment from 1580 kg m -3 at the surface to 1720 kg m -3 at 70 cm. In the upper estuary ?b values were lower at 1170-1200 kg m -3 and profiles were almost homogeneous indicating that consolidation was not occurring. The mid-estuary was transitional between these two situations. These results are consistent with the seasonal accumulation and loss of 'mobile' sediment observed previously in the upper estuary with changes in river flow, and with the apparent stability of intertidal mud in the lower marine estuary deduced from historical bathymetric survey records. The slopes of the intertidal mud banks ranged from 1-2% in the lower estuary to 20-25% in mid-estuary but, instead of continuing to increase in steepness towards the head as the estuary became narrower, the measured slopes actually decreased. It is speculated that the lack of consolidation through continual mobilisation and settlement cycles combined with an increase in silt content in the upper estuary resulted in sediment that lacked the mechanical strength to maintain steep slopes.

Bale, A. J.; Stephens, J. A.; Harris, C. B.

2007-11-01

273

Justice Kennedy's Libertarian Revolution: Lawrence v. Texas  

Microsoft Academic Search

This brief article explains why Lawrence v. Texas could be a revolutionary case if the Supreme Court follows Justice Kennedy's reasoning in the future. As in Planned Parenthood v. Casey, Justice Kennedy finds a statute to be unconstitutional, not because it infringes a right to privacy (which is mentioned but once), but because it infringes \\

Randy E. Barnett

2003-01-01

274

Lawrence Livermore National Laboratory 2007 Annual Report  

Microsoft Academic Search

Lawrence Livermore National Laboratory's many outstanding accomplishments in 2007 are a tribute to a dedicated staff, which is shaping the Laboratory's future as we go through a period of transition and transformation. The achievements highlighted in this annual report illustrate our focus on the important problems that affect our nation's security and global stability, our application of breakthrough science and

P Chrzanowski; K Walter

2008-01-01

275

Lawrence Berkeley Laboratory catalog of research projects  

SciTech Connect

Research from Lawrence Berkeley Laboratory is briefly presented. Topics include: (1) Applied Science; (2) Chemical Sciences; (3) Earth Sciences; (4) Materials Sciences; (5) Accelerator and Fusion Research; (6) Nuclear Science; (7) Physics; (8) Cell and Molecular Biology; (9) Chemical Biodynamics; (10) Research Medicine and Radiation Biophysics; (11) Engineering; (12) Environmental Protection, Health and Safety; and (13) Information and Computing Sciences. (WET)

Not Available

1991-01-01

276

Struggle for the Soul: John Lawrence Childs  

ERIC Educational Resources Information Center

John Lawrence Childs was born in Eau Claire, Wisconsin on January 11, 1889, the second child of John Nelson Childs and Helen Janette (Nettie) Smith. In childhood Childs absorbed the values of industry, democracy, and a traditional, but socially conscious, religion. Childs was a Methodist and an intensely private person not given to talking about…

Stallones, Jared

2010-01-01

277

Winds and the orientation of a coastal plane estuary plume  

Microsoft Academic Search

Based on a calibrated coastal plane estuary plume model, ideal model hindcasts of estuary plumes are used to describe the evolution of the plume pattern in response to river discharge and local wind forcing by selecting a typical partially mixed estuary (the Cape Fear River Estuary or CFRE). With the help of an existing calibrated plume model, as described by

Meng Xia; Lian Xie; Leonard J. Pietrafesa

2010-01-01

278

Health of white sucker within the St. Louis River area of concern associated with habitat usage as assessed using stable isotopes  

EPA Science Inventory

In Spring 2011, 200 adult white sucker were collected in four areas of the St. Louis River Area of Concern (AOC), located in Minnesota and Wisconsin, USA. The areas included the upper AOC as a reference area, the upper estuary, St. Louis Bay and Superior Bay. Grossly visible abno...

279

Modeling nutrient dynamics under critical flow conditions in three tributaries of St. Louis Bay  

Microsoft Academic Search

Previous research results indicated that dry weather condition has complicated impacts on nitrogen dynamics; monitored and modeling data showed both increased and decreased levels. In order to facilitate the total maximum daily loads (TMDLs) development at three tributaries of St. Louis Bay estuary, the nitrogen dynamics were investigated for two designed critical flow conditions by integrating Hydrological Simulation Program Fortran

Zhijun Liu; William L. Kingery; David H. Huddleston; Faisal Hossain; Wei Chen; Noor B. Hashim; Janna M. Kieffer

2008-01-01

280

Dissolved oxygen in two Oregon estuaries: The importance of the ocean-estuary connection - May 16, 2011  

EPA Science Inventory

We examined the role of the ocean ?estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO ...

281

Salinity of the Delaware Estuary  

USGS Publications Warehouse

The purpose of this investigation was to obtain data on and study the factors affecting the salinity of the Delaware River from Philadelphia, Pa., to the Appoquinimink River, Del. The general chemical quality of water in the estuary is described, including changes in salinity in the river cross section and profile, diurnal and seasonal changes, and the effects of rainfall, sea level, and winds on salinity. Relationships are established of the concentrations of chloride and dissolved solids to specific conductance. In addition to chloride profiles and isochlor plots, time series are plotted for salinity or some quantity representing salinity, fresh-water discharge, mean river level, and mean sea level. The two major variables which appear to have the greatest effect on the salinity of the estuary are the fresh-water flow of the river and sea level. The most favorable combination of these variables for salt-water encroachment occurs from August to early October and the least favorable combination occurs between December and May.

Cohen, Bernard; McCarthy, Leo Thomas.

1962-01-01

282

Plankton dynamics along a 180 km reach of the Saint Lawrence River from its headwaters in Lake Ontario  

Microsoft Academic Search

We test the hypothesis that phytoplankton biomass decrease upon entry into the St. Lawrence River from headwaters in Lake\\u000a Ontario is attributable to a range of causal factors including, decreased photosynthetic fitness due to turbulence, cell loss\\u000a due to increased flocculation and subsequent sedimentation, decreases in nutrients, and loss due to grazing. In order to test\\u000a this, changes in phytoplankton

Michael R. Twiss; Carmen Ulrich; Stefanie A. Kring; Jessica Harold; Matthew R. Williams

2010-01-01

283

Postcard Written by Lawrence A. Italiano to the Bryant College Service Club Dated August 26, 1942  

Microsoft Academic Search

[Transcription begins] Pvt. Lawrence Italiano #920 A.A.F. R.T.C. Group E - Sec. 47-RM Atlantic City, N.J.\\u000aAugust 26, 1942 [Postmark date]\\u000aBryant Service Club Hope and Benevolent St. Providence, R.I.\\u000aI’m in the U.S. Army Air Corps for the duration of this war. Atlantic City is a beautiful city and sure has plenty of hotels. I have been writing letters

Lawrence A. Italiano

1942-01-01

284

US Environmental Protection Agency: National Estuary Program  

NSDL National Science Digital Library

Established in 1987 by amendments to the Clean Water Act and administered by the Environmental Protection Agency's Office of Wetlands, Oceans, and Watersheds (OWOW), the National Estuary Program (NEP) identifies, restores and protects estuaries along the coasts of the United States. Unlike the traditional regulatory approaches to environmental protection, the NEP targets a wide range of issues and engages local communities in the process. At the site users can find descriptions of the NEP, specific NEP projects, estuaries involved in the NEP (including location, size, presence of threatened and endangered species, major habitat types, etc.), a current awareness section, links to related sites, and the full text of NEP's newsletter, Coastlines.

285

Obituary: Lawrence Hugh Aller, 1913-2003  

NASA Astrophysics Data System (ADS)

The announcement still lies in my inbox: ``Lawrence Aller died last Sunday." On 16 March 2003, one of the world's fine astronomers passed away at the age of 89, leaving behind a legacy that will ripple as long as there are students of the celestial science, one that incorporated observation, theory, education, care, decency, and kindness. Lawrence was born in the humblest of conditions in Tacoma, Washington, on 24 September 1913. His mother, Lella (Belle) Allen, was a homemaker and his father Leslie Aller, was an occassional printer and gold prospector who thought that the use of the mind was a waste of time. With fierce persistence and dedication, Lawrence pulled off a feat that would probably not be possible now: getting into college without having finished high school, the result of being dragged to work in his father's primitive gold mining camp. His interest, sparked by leaflets from the Astronomical Society of the Pacific and by Russell, Dugan, and Stewart's venerable textbook, led him to a correspondence, and finally a meeting, with Donald Menzel of Harvard, who persuaded the admissions director of the University of California at Berkeley to admit him in 1932. From there, Lawrence went on to graduate school at Harvard and the Harvard Society of Fellows, where he studied with Menzel and developed his interest in stellar and nebular astronomy. After working in the War effort, he made his professorial debut at Indiana University, where he stayed until 1948 before leaving for the University of Michigan. Residing there for the next 14 years, he established his research reputation and helped develop the Michigan graduate program. In 1962, the opportunity arose to return to California, to UCLA, where he again was instrumental in founding a PhD program. There he stayed, through his retirement in 1984, doing research right up to the end. Eight other schools received him as visiting professor. Lawrence knew that to make inroads into astronomy, he needed to apply physics to the observations, which he ardently sought. Little pleased him more than gathering photons, except perhaps for making atomic calculations with which he could analyze spectra. His real love was gaseous nebulae, specifically planetary nebulae (which he called his ``hobby"), the graceful shells of gas surrounding dying stars that are making their transitions to becoming white dwarfs. His range of simultaneous research projects was staggering. Having been an undergraduate student at Michigan in the late 1950s, I followed him to UCLA to work on my doctorate. When I arrived, I found him engaged in stellar spectroscopy, solar research, nebular theory, nebular observations (he tossed a box of plates at me and said in effect, ``here is your thesis"), and of all things Mie scattering theory to explain the zodiacal light! A list of his discoveries and influences is impressive. A sample: Lawrence played a major role in Menzel's group, which produced the famed ``Physical Processes in Gaseous Nebulae," an 18-part series that ran in the Astrophysical Journal from 1937 to 1945 and that explained nebular spectra. He was among the first to promulgate what in the 1940s was utter heresy, that the chemical compositions of stars could differ from one another. He was the first to observe gradients in spiral galaxies, which ultimately turned out to be the result of abundance variations. David Bohm and Lawrence established the existence of Maxwellian velocity distributions in nebular plasmas. Leo Goldberg, Edith Müller, and he were instrumental in establishing the chemical composition of the Sun. His observations of planetaries were legion. Never content with current observational and analytical capabilities, he sought out the latest equipment, from image tubes through CCDs to the best computers, ever looking ahead. His work was honored in 1992, when he received the American Astronomical Society's Russell Prize. Perhaps Lawrence's greatest legacy involved his teaching and writing. At Michigan, he taught a two-semester course in advanced general astronomy that

Kaler, James B.

2003-12-01

286

Lawrence Berkeley Laboratory 1993 Site Environmental Report  

SciTech Connect

This annual Site Environmental Report summarizes Lawrence Berkeley Laboratory`s (LBL`s) environmental activities in calendar year (CY) 1993. The purpose of this report is to characterize site environmental management performance, confirm compliance status with environmental standards and requirements, and highlight significant programs and efforts. Its format and content are consistent with the requirements of the US Department of Energy (DOE) Order 5400.1, General Environmental Protection Program.

Not Available

1994-05-01

287

Lawrence Livermore National Laboratory Summer Employment Summary  

SciTech Connect

This document will serve as a summary of my work activities as a summer employee for the Lawrence Livermore National Laboratory (LLNL). The intent of this document is to provide an overview of the National Ignition Facility (NIF) project, to explain the role of the department that I am working for, and to discuss my specific assigned tasks and their impact on the NIF project as a whole.

Wilson, A J

2002-08-06

288

Nitrogen, Phosphorus, and Suspended Solids Concentrations in Tributaries to the Great Bay Estuary Watershed in 2011.  

National Technical Information Service (NTIS)

Nitrogen, phosphorus, and sediment loads to the Great Bay Estuary are a growing concern. The Piscataqua Region Estuaries Partnership (PREP) calculates the nitrogen load from tributaries to the Great Bay Estuary for its State of the Estuaries reports. Ther...

M. A. Wood P. Trowbridge

2012-01-01

289

Life sciences: Lawrence Berkeley Laboratory, 1988  

SciTech Connect

Life Sciences Research at LBL has both a long history and a new visibility. The physics technologies pioneered in the days of Ernest O. Lawrence found almost immediate application in the medical research conducted by Ernest's brother, John Lawrence. And the tradition of nuclear medicine continues today, largely uninterrupted for more than 50 years. Until recently, though, life sciences research has been a secondary force at the Lawrence Berkeley Laboratory (LBL). Today, a true multi-program laboratory has emerged, in which the life sciences participate as a full partner. The LBL Human Genome Center is a contribution to the growing international effort to map the human genome. Its achievements represent LBL divisions, including Engineering, Materials and Chemical Sciences, and Information and Computing Sciences, along with Cell and Molecular Biology and Chemical Biodynamics. The Advanced Light Source Life Sciences Center will comprise not only beamlines and experimental end stations, but also supporting laboratories and office space for scientists from across the US. This effort reflects a confluence of scientific disciplines --- this time represented by individuals from the life sciences divisions and by engineers and physicists associated with the Advanced Light Source project. And finally, this report itself, the first summarizing the efforts of all four life sciences divisions, suggests a new spirit of cooperation. 30 figs.

Not Available

1989-07-01

290

Ephemeral Estuaries of the Deltaic Environment.  

National Technical Information Service (NTIS)

The usual definition of the term estuary is not sufficiently inclusive. Most textbook descriptions apply to coastal indentations like the Scandanavian fjords or drowned river mouths like the Chesapeake or Delaware Bays. In addition to these rather obvious...

J. P. Morfan

1967-01-01

291

ECOLOGICAL CONDITION OF SOUTH FLORIDA ESTUARIES  

EPA Science Inventory

An assessment of the ecological condition of south Florida estuaries based on regional probabilistic monitoring was conducted during the summer of 1995. Samples and data were collected on water and sediment quality, benthos, and fish tissue contaminants. Elevated concentrations o...

292

EPA'S BENTHIC HABITAT DATA FOR YAQUINA ESTUARY  

EPA Science Inventory

Scientists at EPA's National Health and Environmental Effects Research Laboratory, Western Ecology Division (WED) have been studying seafloor (benthic) habitats in Yaquina estuary for several years. Those studies were conducted as parts of several research projects, including: e...

293

Methane distribution in European tidal estuaries  

Microsoft Academic Search

Methane concentrations have been measured along salinity profilesin nine tidal estuaries in Europe (Elbe, Ems, Thames, Rhine,Scheldt, Loire, Gironde, Douro and Sado). The Rhine, Scheldt andGironde estuaries have been studied seasonally. A number ofdifferent methodologies have been used and they yieldedconsistent results. Surface water concentrations ranged from0.002 to 3.6 µM, corresponding to saturation ratios of 0.7 to1580 with a median

Jack J. Middelburg; Joop Nieuwenhuize; Niels Iversen; Nana Høgh; Hein de Wilde; Wim Helder; Richard Seifert; Oliver Christof

2002-01-01

294

Iodine speciation in the Nile River estuary  

Microsoft Academic Search

During high- and low-flood periods, surface and bottom water samples were collected along the Nile River estuary for the voltammetric determination of dissolved iodine species. Iodine occurs in the estuary as iodate, iodide and organic iodine. Total iodine increases with salinity, showing a source feature in surface and bottom waters during high-flow indicating iodine input. During low-flow, total iodine showed

M. A. R Abdel-Moati

1999-01-01

295

Water renewal timescales in the Scheldt Estuary  

NASA Astrophysics Data System (ADS)

Using the concepts of the Constituent-oriented Age and Residence time Theory (CART), we compute timescales related to the water renewal in the Scheldt Estuary (The Netherlands/Belgium). Three different timescales are used to better understand and characterize the dynamics of the estuary: the age of the renewing water, the residence time and the exposure time. The residence time is the time taken by a water parcel to leave the estuary for the first time while the exposure time is the total time spent by a water parcel in the estuary including re-entries. The age of a renewing water parcel is defined as the time elapsed since it entered the estuary. The renewing water was split into three types: the water originating from the sea, the water originating from the upstream fresh tidal rivers and the water originating from the different canals and docks connected to the estuary. Every timescale is computed at any time and position by means of the finite-element, unstructured-mesh model SLIM. This results in movies of the timescale fields (shown as Supplementary material), allowing a detailed analysis of their spatial and temporal variabilities. The effect of the M2 tide and the discharge regime (winter, summer or average situation) on the timescales is also investigated. Tidally-averaged timescales vary little over the width of the estuary and hence exhibit a virtually one-dimensional behaviour. However, around these average values, the timescales can vary hugely over a tidal cycle, with amplitudes that significantly depend on the space coordinates. The reason thereof has yet to be elucidated. These results underscore the need for two- or three-dimensional models with high temporal resolution for investigating the dynamics of the Scheldt Estuary.

de Brye, Benjamin; de Brauwere, Anouk; Gourgue, Olivier; Delhez, Eric J. M.; Deleersnijder, Eric

2012-06-01

296

Use of a Date-specific Method to Examine Variability in the Flushing Times of Georgia Estuaries  

Microsoft Academic Search

The fraction of freshwater method (Dyer, 1973) was used to examine the general characteristics of flushing time in five riverine estuaries in Georgia, U.S.A. Median flushing times over a 30-year period (1968–1997) were as follows: Savannah (5·6 days), Ogeechee (20·7 days), Altamaha (5·8 days), Satilla (66·8 days), and St. Marys (71·6 days), although there was considerable inter- and intra-annual variability

M. Alber; J. E. Sheldon

1999-01-01

297

Estuaries.  

ERIC Educational Resources Information Center

This publication is designed for use in standard science curricula to develop oceanologic manifestations of certain science topics. Included are teacher guides, student activities, and demonstrations designed to impart ocean understanding to high school students. When the student has completed this unit, he should be able to: (1) define an…

Awkerman, Gary L.

298

ESTIMATING THE CONDITION OF GULF OF MEXICO ESTUARIES: NATIONAL COASTAL ASSESSMENT AND NATIONAL ESTUARY PROGRAM  

EPA Science Inventory

Estuaries in the Gulf of Mexico have been monitored since 1991 to determine the condition of water, sediment, and biota. More recently, through the National Coastal Assessment (NCA), U.S. EPA has provided a comprehensive estimate of the condition of U.S. estuaries, including a re...

299

The Estuary Book: A Guide to Promoting Understanding and Regional Management of Maine's Estuaries and Embayments.  

ERIC Educational Resources Information Center

The objective of this document is to provide information about estuaries, the impact of uses on the environmental health of an estuary, and what communities and concerned individuals can do to manage and protect their local estuarine resources successfully. Much of the information presented here pertains to other embayments along the Maine coast…

Ruffing, Jenny

300

Life History and Population Characteristics of Striped Bass in Atlantic Canada  

Microsoft Academic Search

Populations of striped bass Morone saxatilis occur in three regions of Atlantic Canada: the St. Lawrence River and estuary in Quebec; the Gulf of St. Lawrence from Chaleur Bay through Northumberland Strait; and rivers in New Brunswick and Nova Scotia draining into the Bay of Fundy. At least nine rivers are known or believed to sustain spawning populations: the St.

Roger A. Rulifson; Michael J. Dadswell

1995-01-01

301

Technology transfer at Lawrence Berkeley Laboratory  

SciTech Connect

Lawrence Berkeley Laboratory (LBL) is dedicated to commercializing new technology in such fields as advanced materials, biotechnology, and electronics. Technology transfer between national laboratories and the industrial community is important in maintaining America`s competitive edge. This document examines opportunities to establish working relationships with LBL. Streamlined methods for technology transfer are available with the aid of the Technology Transfer Department and the Patent Department at LBL. Research activities at LBL are concentrated in three major program areas: Energy Sciences, General Sciences, and Biosciences. Each program area consists of three research divisions. LBL welcomes both requests for information and proposals to conduct research.

Johnson, D. [ed.

1992-09-01

302

Technology transfer at Lawrence Berkeley Laboratory  

SciTech Connect

Lawrence Berkeley Laboratory (LBL) is dedicated to commercializing new technology in such fields as advanced materials, biotechnology, and electronics. Technology transfer between national laboratories and the industrial community is important in maintaining America's competitive edge. This document examines opportunities to establish working relationships with LBL. Streamlined methods for technology transfer are available with the aid of the Technology Transfer Department and the Patent Department at LBL. Research activities at LBL are concentrated in three major program areas: Energy Sciences, General Sciences, and Biosciences. Each program area consists of three research divisions. LBL welcomes both requests for information and proposals to conduct research.

Johnson, D. (ed.)

1992-09-01

303

Lawrence Berkeley Laboratory 1994 site environmental report  

SciTech Connect

The 1994 Site Environmental Report summarizes environmental activities at Lawrence Berkeley Laboratory (LBL) for the calendar year (CY) 1994. The report strives to present environmental data in a manner that characterizes the performance and compliance status of the Laboratory`s environmental management programs when measured against regulatory standards and DOE requirements. The report also discusses significant highlight and planning efforts of these programs. The format and content of the report are consistent with the requirements of the U.S. Department of Energy (DOE) Order 5400.1, General Environmental Protection Program.

NONE

1995-05-01

304

Micro network unburdens Lawrence Livermore's supercomputers  

SciTech Connect

Many program-development installations that rely on time-sharing systems are distributing some of the programming tasks to microcomputer networks. The Lawrence Livermore National Laboratory, for example, has installed several microcomputer local networks as front-ends to its massive Octopus network, composed of Cray-1 and Control Data Corp. 7600 mainframes. One local network, which incorporated terminals from different vendors, is used by the programming group for nuclear weapons simulation. It allows programmers to perform local text editing, which reduces the time necessary to retrieve, modify and verify code, and frees the central host for compilation and execution. It also facilitates job resubmission and user scheduling.

Cecil, A.

1983-03-01

305

Organic Carbon and Deoxygenation in the Pamlico River Estuary.  

National Technical Information Service (NTIS)

The distribution, sources and sinks of organic carbon were studied in the Pamlico River Estuary during 1975-1977. The main source of organic carbon was from phytoplankton productivity, which, together with other sources from within the estuary, provided 6...

G. J. Davis M. M. Brinson W. A. Burke

1978-01-01

306

A Bioenergetics Modeling Evaluation of Top-down Control of Ruffe in the St. Louis River, Western Lake Superior  

Microsoft Academic Search

Ruffe (Gymnocephalus cernuus), were accidentally introduced into the St. Louis River estuary, western Lake Superior, in the mid 1980s and it was feared that they might affect native fish through predation on eggs and competition for forage and habitat. In an effort to control the abundance of ruffe and limit dispersal, a top-down control strategy using predators was implemented in

Kathleen R. Mayo; James H. Selgeby; Michael E. McDonald

1998-01-01

307

Seasonal variation of sediment deposition in the Hudson River estuary  

Microsoft Academic Search

During and following the spring freshet, rapid rates of sediment deposition were observed in the Hudson River estuary. Side-scan sonar surveys and sediment coring studies revealed a large amount of spatial variability in sedimentation within the estuary and a distinct seasonal progression. During the freshet, sediment was deposited in the seaward reaches of the estuary. In the two-month period after

Jonathan D Woodruff; W. Rockwell Geyer; Christopher K Sommerfield; Neal W Driscoll

2001-01-01

308

Rapid barium removal in the Delaware estuary  

SciTech Connect

Six profiles of dissolved barium covering the entire salinity range of the Delaware River and Bay estuary from March through September 1996 were collected and analyzed. The profiles are similar to one another in both shape and magnitude except for one attribute. A sudden ({le} 24 days), nearly complete (>90%) removal of dissolved Ba in midestuary occurs in mid-May followed by an 80% recovery in early June. This removal appears to be temporally and spatially coupled to the end of the spring bloom. Based on such episodic behavior, and on recent work with flocculation of diatom exudates, the authors conclude that the Ba depletion is caused by barite precipitation in the estuary during the late stages of the bloom. This would imply that lower estuary and inner coastal margin sediments associated with eutrophic estuaries receive a seasonal pulse of barite. The suddenness of this event also implies that sedimentary barite is strongly influenced by high productivity events. Comparison of the riverine Ba concentration with the effective riverine end member after desorptive barium release yields an estimated 30--40 nM Ba available from the suspended sediments as they enter the estuary. This estimate is supported by excess barium in unfiltered samples over filtered samples taken from the river and also by calculations done elsewhere.

Stecher, H.A. III [Univ. of Delaware, Lewes, DE (United States). College of Marine Studies] [Univ. of Delaware, Lewes, DE (United States). College of Marine Studies; [Univ. of Delaware, Newark, DE (United States). Dept. of Geology; Kogut, M.B. [Univ. of Washington, Seattle, WA (United States). School of Oceanography] [Univ. of Washington, Seattle, WA (United States). School of Oceanography

1999-04-01

309

The geochemistry of a subterranean estuary  

NASA Astrophysics Data System (ADS)

A comprehensive geochemical study of the subterranean estuary underlying Waquoit Bay (Cape Cod, MA, USA) has been undertaken. Sediment and pore water samples across the groundwater-seawater mixing zone show that the porous sediments support an active biogeochemistry. The redox cycles of iron and manganese are well developed with the oxidation of dissolved ferrous iron forming extensive deposits of iron-oxide coated sands. The strong relationship between the sediment concentrations of Fe and P reflects the sorption of phosphate from seawater and/or groundwater. Though two orders of magnitude less abundant than iron oxides, manganese oxides also precipitate in the subterranean estuary. Recirculation of seawater past the iron-rich sediments under reducing conditions makes this subterranean estuary a net sink for U from coastal seawater. In contrast, large scale release of Ba occurs in the mid to high salinity zone of the subterranean estuary, leading to a net source of Ba to the coastal ocean. While salt-induced desorption of Ba from the sediments may be an important process, a strong correlation with dissolved Mn suggests that sorbed-Ba is also released during the reductive dissolution of Mn oxides. Finally, the Ba results may provide insight into the processes controlling Ra cycling in the subterranean estuary and, therefore, its use as a tracer of submarine groundwater discharge to the oceans.

Charette, M. A.; Sholkovitz, E. R.

2003-04-01

310

St. John's Wort (image)  

MedlinePLUS

The herb St. John's Wort is believed to be helpful in relieving mild to moderate depression, but should only be taken under a physician's supervision. St. John's Wort may clash with other medications or foods ...

311

St. John's wort  

MedlinePLUS

... is risky. It can cause serious sensitivity to sunlight. St. John’s wort is native to Europe but ... acid can make your skin sensitive to the sunlight. St. John's wort might also increase your sensitivity ...

312

A comparative study of mercury contamination in the Tagus estuary (Portugal) and major French estuaries (Gironde, Loire, Rhône)  

NASA Astrophysics Data System (ADS)

Concentrations of mercury were determined for the waters, suspended matter and sediments of the Tagus and of major French estuaries. The Tagus estuary is one of the most contaminated by mercury derived from the outfalls of a chloralkali plant and from other industrial sources. In deposited sediments the median level, 1·0 ?g Hg g -1, is twenty times higher than the natural background and Hg contents depend on the sediment grain-size, age and the distance from waste-outfalls. Suspended matter is more regularly and highly contaminated (median value: 4·5 ?g Hg g -1). In the French estuaries Hg levels in the suspended material decrease with salinity due to dilution and/or remobilization processes. In June 1982, in the Loire estuary, high values of Hg are observed in the middle estuary and attributed to urban and industrial sources. In the Tagus estuary, the general distribution of total dissolved Hg confirms the contamination: it increases seaward from 10 ng 1 -1 in the river to 80 ng 1 -1 in the estuary outlet. The dissolved Hg is almost totally organic in the river, inorganic in the middle estuary due to inorganic Hg effluents and again organic in the lower estuary. This variation is related to the dissolved organic carbon values. The dissolved Hg levels in the Loire Estuary (5-300 ng 1 -1) are much higher than in the Gironde estuary (3-6 ng 1 -1) and of the same order as those observed in the Tagus estuary.

Figueres, G.; Martin, J. M.; Meybeck, M.; Seyler, P.

1985-02-01

313

Impact of the Clean Water Act on the levels of toxic metals in urban estuaries: The Hudson River estuary revisited  

Microsoft Academic Search

To establish the impact of the Clean Water Act on the water quality of urban estuaries, dissolved trace metals and phosphate concentrations were determined in surface waters collected along the Hudson River estuary between 1995 and 1997 and compared with samples collected in the mid-1970s by Klinkhammer and Bender. The median concentrations along the estuary have apparently declined 36--56% for

S. A. Sanudo-Wilhelmy; Gary A. Gill

1999-01-01

314

Nutrient transports in a Swedish estuary  

NASA Astrophysics Data System (ADS)

Himmerfjärd is a Swedish estuary bordering on the Baltic. The estuary lacks astronomical tides and its circulation is driven by winds and freshwater runoff. Because of a tertiary sewage treatment plant located at its inner end, the estuary is becoming increasingly eutrophic. A field study was carried out for a 78-day period in late summer and early fall of 1977 to determine rates of nutrient transport and to construct nutrient budgets. Since physical parameters (current velocity, temperature, salinity, winds and water level changes) were measured more frequently than nutrients (phosphate, nitrate, nitrite and ammonium) it was necessary to develop a suitable method to calculate nutrient flux time series and net nutrient fluxes. Over the study period, Himmerfjärd imported phosphorus and exported nitrogen. Direction of nutrient fluxes and changes in flux direction were consistent with the structure of the baroclinic currents.

Wilmot, Wayne; Toll, Peter; Kjerfve, Björn

1985-08-01

315

Public attitudes toward Lawrence Livermore National Laboratory  

SciTech Connect

Charlton Research Company is pleased to present the following summary of findings report for research conducted under contract with Lawrence Livermore National Laboratory. This section provides a brief introduction to the specifications of the study, and a guide to the organization of this report. Although the most sophisticated procedures have been used to collect and analyze the information presented here, it must be remembered that qualitative and quantitative research are not predictions. They are designed to measure public opinion within identifiable statistical limits or accuracy at specific points in time. This research is in no way a prediction of opinion or action at any future point in time. Among the topics covered in the surveys are: openness; National Laboratory; health hazards; radioactivity; uses of plutonium; hazardous waste; groundwater pollution; nuclear weapons; Ballistic Missile Defense; and earthquakes.

Not Available

1990-05-01

316

Decadal mercury trends in San Francisco Estuary sediments.  

PubMed

Monitoring sediment quality and total mercury concentrations over the period 1993-2001 at 26 stations in San Francisco Estuary has shown the seasonal cycling of mercury sediment concentrations, as well as a significant (P < 0.05) decrease in those concentrations at eight stations across the estuary. This decrease in sediment mercury concentrations is attributed to the transport of relatively cleaner sediment to the estuary from the Sacramento River and San Joaquin River watersheds. Despite the decreases observed in some parts of the estuary, no corresponding trend has been found in concurrent studies on sport fish and bivalves in the estuary. PMID:17161835

Conaway, Christopher H; Ross, John R M; Looker, Richard; Mason, Robert P; Flegal, A Russell

2007-09-01

317

Astronauts Grunsfeld and Lawrence on middeck with ergometer  

NASA Technical Reports Server (NTRS)

Astronauts John M. Grunsfeld and Wendy B. Lawrence exercise on the middeck of the Earth-orbiting Space Shuttle Endeavour during the STS-67 mission. While Grunsfeld's pedaling is done on a real bicycle ergometer, Lawrence's movements are a convincing simulation without hardware.

1995-01-01

318

San Francisco Estuary: Invasive Spartina Project  

NSDL National Science Digital Library

The Invasive Spartina Project was developed by the California State Coastal Conservancy to determine the extent and address the problem of invasive Spartina in the San Francisco Estuary. This Web site describes the efforts of the Invasive Spartina Project and the risk that Spartina poses. A variety of maps and photos are used to describe the results of the 2000-2001 survey of Spartina populations within the estuary. A host of other documents regarding Spartina and this project are also available in Adobe Acrobat (.pdf) format.

2002-01-01

319

RIVERINE ESTUARY CLASSIFICATION FOR THE SAKE OF ENVIRONMENTAL CONSERVATION  

NASA Astrophysics Data System (ADS)

The environment of riverine estuaries is characterized by many factors including tidal oscillation, river flow and morphology, and the combination of these factors makes each estuary unique in its environment. However, there are similarities among some estuaries. We have tried to classify Japan’s 109 riverine estuaries based on physical environmental factors like tidal oscillation, wave energy, and high and low river flow. 109 riverine estuaries were divided into 5 classifications. Fish species monitoring data have also been analyzed to categorize riverine estuaries and the results were compared to 5 classifications divided by physical factors. Since our physical and biological classification both seemed to be related to the salinity of the estuary, these two classifications showed fair conformity.

Kishida, Hiroyuki; Amano, Kunihiko; Oonuma, Katsuhiro; Endoh, Maremi

320

PECONIC ESTUARY: AN ASSESSMENT OF SHELLFISH RESOURCES IN THE TRIBUTARIES AND EMBAYMENTS OF THE PECONIC ESTUARY  

EPA Science Inventory

Executive Summary Historically, the Peconic Estuary's shellfish resources have supported significant fisheries for a number of species including hard clams, oysters and bay scallops. However, distribution and abundance data for the tributaries and embayments within the Peconic Es...

321

Control of phytoplankton biomass in estuaries: A comparative analysis of microtidal and macrotidal estuaries  

Microsoft Academic Search

Macrotidal estuaries (mean tidal range >2m) generally exhibit a tolerance to pollution with nitrogen-containing nutrients\\u000a despite high loadings originating from freshwater outflows. These systems, which are characterized by high tidal energy, generally\\u000a exhibit lower levels of chlorophylla than systems with lower tidal energy. A comparative analysis of data from 40 microtidal and macrotidal estuaries shows that\\u000a mean annual chlorophylla levels

Yves Monbet

1992-01-01

322

A Multi-Scale Analysis of Grassland Bird Habitat Relationships in the St. Lawrence River Valley  

Microsoft Academic Search

I used a combination of 10 vegetation variables and 10 landscape variables to model abundance and occurrence of six grassland bird species in agricultural grassland (n=55) throughout Jefferson County, NY during the 2004 and 2005 field seasons. Landscape composition was quantified by classifying the proportion of land use within a 1 km radius from the center of all survey fields.

Sarah A. Lazazzero

2006-01-01

323

Ground-water availability from the unconsolidated deposits of the St. Lawrence River Basin, New York  

USGS Publications Warehouse

Protection of New York State 's aquifers has become an increasingly important issue among water resource managers at all levels of State and Local government. Aquifer delineation is necessary as an initial phase in the effective management of the State 's groundwater resources. Many of New York 's productive aquifers consist of unconsolidated deposits. In an effort to obtain complete coverage of all the significant unconsolidated aquifers in New York, the U.S. Geological Survey and the New York State Department of Environmental Conservation began a cooperative study in 1985 to compile groundwater availability maps of each major river basin. This map delineates the unconsolidated aquifers that underlie the State 's northernmost eight counties and gives the estimated potential yield of properly constructed wells completed in these aquifers. Additional well locations and delineation of the aquifers were obtained through a well inventory conducted during the study. (Lantz-PTT)

Bugliosi, Edward F.

1987-01-01

324

Acoustic detection of a scallop bed from a single-beam echosounder in the St. Lawrence  

Microsoft Academic Search

Single-beam seabed echoes combined with epi-macrobenthos photographs were used to remotely detect a scallop bed and characterize the specific acoustic signal of Iceland scallop (Chlamys islandica). A dense scallop bed was surveyed in 2002, with a QTC VIEW Series IV acoustic ground-discrimination system (AGDS) connected to a 38 kHz, 7( split-beam SIMRAD EK60 scientific echosounder. In 2003, a 50 kHz,

Estelle Hutin; Yvan Simard; Philippe Archambault

2005-01-01

325

Great Lakes/St. Lawrence Seaway Regional Transportation Study; Analysis of Freight Rates.  

National Technical Information Service (NTIS)

This report is the documentation of the freight rate data base for an evaluation of NED transportation benefits for GL/SLS navigation improvements. This report provides the Great Lakes total logistics cost and a similar cost for an alternate transportatio...

1981-01-01

326

Great Lakes/St. Lawrence Seaway regional transportation study; Great Lakes area industries. Final report  

SciTech Connect

This report is a general description of the major industries which are responsible for shipments for major commodities via the Great Lakes. These industry studies define the general framework for projection of bulk cargo forecasts.

Not Available

1981-11-01

327

Citizens' Guide to Biomonitoring in the Great Lakes and St. Lawrence River.  

ERIC Educational Resources Information Center

The purpose of this report is to present the issues surrounding biomonitoring of wastewaters discharged into the Great Lakes Basin. Biomonitoring is the process of using organisms to monitor the toxicity of a substance. The report reflects an interest in seeing zero discharge of toxic pollutants in the Great Lakes region. The report is organized…

Great Lakes United, Buffalo, NY.

328

Investigation of surface topography differences in native and exotic invertebrates in the St. Lawrence River.  

PubMed

The texture, or topography, interior of shells from native and exotic mollusks are measured and compared to determine if they can be discriminated. Area-scale fractal analysis is used to calculate relative areas as a function of scale, and the relative areas are used to evaluate the measurements. Measurements from a scanning laser profiler and from confocal and interferometric microscopes are compared, as are measurements of an original and a replica. The relative areas indicate clear differences between the measurement instruments. The largest relative areas are calculated from the confocal measurements. The trueness of the measurements has not been determined. However, the relative areas calculated from the confocal measurements are capable of discriminating the native clam from the exotic mussels with a confidence of greater than 99% at scales below 10?µm². PMID:20949618

Brown, D R S; Brown, C A

2010-01-01

329

Shoreline retreat and coastal storms in the southern Gulf of St. Lawrence  

NASA Astrophysics Data System (ADS)

Submerged fluvial channels and estuarine facies seaward of the sandy North Shore of Prince Edward Island (Canada) attest to long-term mean relative sea-level rise >2.5 mm/a driving coastal retreat at mean rates >0.5 m/a over the past six thousand years. The shoreface, nearshore multiple bar complexes, and beaches are sand-limited and sand is transferred landward into multidecadal to century-scale storage in coastal dune and flood-tidal delta sinks. Stringent quality control of tide-gauge records for Charlottetown (PEI) indicates mean relative sea-level rise of 3.2 mm/a since 1911. When differenced from tidal predictions, this record provides a decadal sequence of storm surge occurrence for comparison with wind, wave hindcast, and sea-ice data for the southern Gulf over the past several decades. Soft photogrammetric digital rectification of vertical air photographs (1935, 1958, 1968, 1980/1981, 1990) and ground surveys (1989-2001) show large spatial and temporal variance in coastal recession rates, poorly correlated with the overall storm record, in part because of wave suppression by sea ice. Retreat of low sandstone-till cliffs at <1 m/a shows no statistically significant decadal variance. Other sites with shoreline retreat rates typically between 0.5 and 1.5 m/a show localized acceleration after 1980, reflecting a combination of storm impacts, morphodynamic change and sand loss to adjacent tidal inlets. Individual large storms cause localized rapid erosion, from which recovery depends in part on local sand supply. Some barrier shores with dunes show high longshore and interdecadal variance, and extensive multidecadal healing of former inlet and washover gaps. In some areas, at least, this reflects recovery from an episode of widespread washover predating the 1935 photography.

Forbes, D. L.; Parkes, G.; Manson, G. K.; Ketch, L.; Solomon, S. M.

2001-05-01

330

PCB-DECHLORINATING MICROBIAL POPULATIONS IN ST. LAWRENCE RIVER SEDIMENTS. (R825449)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

331

DISTRIBUTION AND TRANSFORMATION OF ELEMENTAL MERCURY IN THE ST. LAWRENCE RIVER AND LAKE ONTARIO. (R827915)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

332

Petrology/Geochemistry/Mineralogy/Structure of Shear zones in St. Lawrence County  

NSDL National Science Digital Library

These rocks were collected from outcrops frequented by structural geology field trips. CCM 42 is from the town of Clare, CCM 43 is from Russell; although labeled CCM, neither is from the Carthoage Colton Mylonite Zone, but both are from shear zones. DEK is from the world famous DeKalb anticline. In this lab we try to pull together material from petrology, geochemistry, mineralogy and structure.

Badger, Robert

333

Nutrient elements in large Chinese estuaries  

NASA Astrophysics Data System (ADS)

Based on comprehensive observations since 1983, this study summarizes major features of nutrient elements (nitrogen, phosphorus and silicon) in large Chinese river/estuary systems. Elevated nutrient element levels were observed in Chinese rivers, when compared to large and less disturbed aquatic systems (e.g. the Amazon, Zaire and Orinoco). Data from this study are similar to those obtained from the polluted and/or eutrophic rivers in Europe and North America (e.g. the Rhóne and Loire). Nutrient elements may have either conservative or active distributions, or both, in the mixing zone, depending on the element and the estuary. For example, non-conservative behaviors were observed in the upper estuary, where nutrient elements may be remobilized due to the strong desorption and variations of the fresh water end-member, but conservative distributions were found afterwards in the lower estuary. Outside the riverine effluent plumes, nutrient elements may be depleted in surface waters relative to elevated bioproduction, whereas the regeneration with respect to decomposition of organic material and/or nitrification/denitrification offshore, may sustain high levels of nutrient elements in near-bottom waters. Laboratory experiment data generally compares well with field observations. The high fluxes and area] yields of nutrient elements from large Chinese rivers, indicate the extensive use of chemical fertilizers and domestic waste drainage over watersheds in China.

Zhang, Jing

1996-07-01

334

INDICATORS OF ECOSYSTEM INTEGRITY FOR ESTUARIES  

EPA Science Inventory

Jordan, Stephen J. and Lisa M. Smith. In press. Indicators of Ecosystem Integrity for Estuaries. In: Proceedings of the Estuarine Indicators Workshop, 29-31 October 2003, Sanibel Island, FL. Sanibel-Captiva Conservation Foundation, Sanibel, FL. 23 p. (ERL,GB 1194). Ideal ...

335

BATHYMETRY FOR ALBEMARLE AND PAMLICO ESTUARIES, NC  

EPA Science Inventory

Bathymetry for the Albemarle and Pamlico Estuaries obtained from National Oceanographic and Atmospheric Administration-National Ocean Service (NOAA-NOS). See the metadata within the files from NOAA-NOS for more details and warnings concerning merging with US Geolgoical Survey Dig...

336

Climate change and its impacts on estuaries  

EPA Science Inventory

Past, present, and future research by WED scientists in the TEP region will be described to lay the foundation for examination of potential climate change effects on estuaries and the broader coastal zone in the Pacific Northwest (PNW). Results from National Coastal Assessments,...

337

MODELING FINE SEDIMENT TRANSPORT IN ESTUARIES  

EPA Science Inventory

A sediment transport model (SEDIMENT IIIA) was developed to assist in predicting the fate of chemical pollutants sorbed to cohesive sediments in rivers and estuaries. Laboratory experiments were conducted to upgrade an existing two-dimensional, depth-averaged, finite element, coh...

338

BCG Approaches for Improved Management of Estuaries  

EPA Science Inventory

Estuaries and other complex aquatic systems are exposed to a variety of stressors that act at several scales, but are managed piecemeal - - often resulting in a ?death by 1000 cuts? caused by cumulative impacts to these valued resources. To address this, managers need tools that...

339

Predicting Bankfull Discharge in Ungauged Estuaries by Explaining the Physical Relation Between the Morphology and Hydrology of Estuaries  

NASA Astrophysics Data System (ADS)

River discharge is a very important parameter in morphological and hydrodynamic studies of estuaries. However, it is always difficult to accurately measure river discharge, and in particular the bankfull discharge in estuaries where the tidal discharge dominates over river discharge. Until today, little research has been done in finding a simple and useful approach to estimate the river discharge in the tidal region, and most of the previous studies focused on the river regime. In this study, we found that there appear to be empirical relations that link together the morphology and hydrology of estuaries, which can be used to estimate river discharge with the least amount of data available. The aims of this study are: 1) to discover the physical explanation for the empirical relation that exists between geometrical characteristics of estuaries and the bankfull flood discharge; and 2) to estimate bankfull discharge in estuaries from the relationship. The physical connection between the estuaries and river regime is found by incorporating the estuary shape analysis and tidal dynamic analysis to Lacey's hydraulic geometry theory. Relationship between the estuary depth and the bankfull river discharge has been analyzed in 19 estuaries around the world (with 9 recently surveyed estuaries). In this study, the discharge data (from gauging station located further upstream) were adjusted by a projection approach to improve the discharge measurement. The outcome of the relationship was compared to Lacey's theory of hydraulic geometry. From the analysis, it shows that the depth of an estuary is a function of the bankfull flood discharge to the power of 1/3 which indicates an agreement with Lacey's formula. With the physical explanation, engineers would be able to estimate flood discharge characteristics from estuary shape indicators. This could be very useful to estimate the flood discharge in ungauged estuaries on the basis of readily available data. In order to verify the accuracy of the relation, existing and new measurement data from estuaries worldwide will be collected and compiled to strengthen the reliability of this finding.

Gisen, J.; Savenije, H.

2013-12-01

340

Lawrence Livermore National Laboratory Environmental Report 2010  

SciTech Connect

The purposes of the Lawrence Livermore National Laboratory Environmental Report 2010 are to record Lawrence Livermore National Laboratory's (LLNL's) compliance with environmental standards and requirements, describe LLNL's environmental protection and remediation programs, and present the results of environmental monitoring at the two LLNL sites - the Livermore site and Site 300. The report is prepared for the U.S. Department of Energy (DOE) by LLNL's Environmental Protection Department. Submittal of the report satisfies requirements under DOE Order 231.1A, Environmental Safety and Health Reporting, and DOE Order 5400.5, Radiation Protection of the Public and Environment. The report is distributed electronically and is available at https://saer.llnl.gov/, the website for the LLNL annual environmental report. Previous LLNL annual environmental reports beginning in 1994 are also on the website. Some references in the electronic report text are underlined, which indicates that they are clickable links. Clicking on one of these links will open the related document, data workbook, or website that it refers to. The report begins with an executive summary, which provides the purpose of the report and an overview of LLNL's compliance and monitoring results. The first three chapters provide background information: Chapter 1 is an overview of the location, meteorology, and hydrogeology of the two LLNL sites; Chapter 2 is a summary of LLNL's compliance with environmental regulations; and Chapter 3 is a description of LLNL's environmental programs with an emphasis on the Environmental Management System including pollution prevention. The majority of the report covers LLNL's environmental monitoring programs and monitoring data for 2010: effluent and ambient air (Chapter 4); waters, including wastewater, storm water runoff, surface water, rain, and groundwater (Chapter 5); and terrestrial, including soil, sediment, vegetation, foodstuff, ambient radiation, and special status wildlife and plants (Chapter 6). Complete monitoring data, which are summarized in the body of the report, are provided in Appendix A. The remaining three chapters discuss the radiological impact on the public from LLNL operations (Chapter 7), LLNL's groundwater remediation program (Chapter 8), and quality assurance for the environmental monitoring programs (Chapter 9). The report uses System International units, consistent with the federal Metric Conversion Act of 1975 and Executive Order 12770, Metric Usage in Federal Government Programs (1991). For ease of comparison to environmental reports issued prior to 1991, dose values and many radiological measurements are given in both metric and U.S. customary units. A conversion table is provided in the glossary.

Jones, H E; Bertoldo, N A; Campbell, C G; Cerruti, S J; Coty, J D; Dibley, V R; Doman, J L; Grayson, A R; MacQueen, D H; Wegrecki, A M; Armstrong, D H; Brigdon, S L; Heidecker, K R; Hollister, R K; Khan, H N; Lee, G S; Nelson, J C; Paterson, L E; Salvo, V J; Schwartz, W W; Terusaki, S H; Wilson, K R; Woods, J M; Yimbo, P O; Gallegos, G M; Terrill, A A; Revelli, M A; Rosene, C A; Blake, R G; Woollett, J S; Kumamoto, G

2011-09-14

341

Nutrient budgets for large Chinese estuaries  

NASA Astrophysics Data System (ADS)

Chinese rivers deliver about 5-10% of global freshwater input and 15-20% of the global continental sediment to the world ocean. We report the riverine fluxes and concentrations of major nutrients (nitrogen, phosphorus, and silicon) in the rivers of the contiguous landmass of China and Korea in the northeast Asia. The rivers are generally enriched with dissolved inorganic nitrogen (DIN) and depleted in dissolved inorganic phosphate (PO43-) with very high DIN: PO43- concentration ratios. DIN, phosphorus, and silicon levels and loads in rivers are mainly affected by agriculture activities and urbanization, anthropogenic activities and adsorption on particulates, and rock types, climate and physical denudation intensity, respectively. Nutrient transports by rivers in the summer are 3-4 times higher than those in the winter with the exception of NH4+. The flux of NH4+ is rather constant throughout the year due to the anthropogenic sources such as the sewer discharge. As nutrient composition has changed in the rivers, ecosystems in estuaries and coastal sea have also changed in recent decades. Among the changes, a shift of limiting nutrients from phosphorus to nitrogen for phytoplankton production with urbanization is noticeable and in some areas silicon becomes the limiting nutrient for diatom productivity. A simple steady-state mass-balance box model was employed to assess nutrient budgets in the estuaries. The major Chinese estuaries export <15% of nitrogen, <6% of phosphorus required for phytoplankton production and ~4% of silicon required for diatom growth in the Chinese Seas (Bohai, Yellow Sea, East China Sea, South China Sea). This suggests that land-derived nutrients are largely confined to the immediate estuaries, and ecosystem in the coastal sea beyond the estuaries is mainly supported by other nutrient sources such as regeneration, open ocean and atmospheric deposition.

Liu, S. M.; Hong, G.-H.; Zhang, J.; Ye, X. W.; Jiang, X. L.

2009-10-01

342

Nitrogen, Phosphorus, and Suspended Solids Concentrations in Tributaries to the Great Bay Estuary Watershed in 2010. Final Report.  

National Technical Information Service (NTIS)

Nitrogen, phosphorus, and sediment loads to the Great Bay Estuary are a growing concern. The Piscataqua Region Estuaries Partnership (PREP) calculates the nitrogen load from tributaries to the Great Bay Estuary for its State of the Estuaries reports. Ther...

M. A. Wood P. Trowbridge

2011-01-01

343

75 FR 17382 - Small Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Water...  

Federal Register 2010, 2011, 2012, 2013

...Specified Activities; Russian River Estuary Water Level Management Activities, California...Authorization (IHA) to the Sonoma County Water Agency (herein after ``Agency...incidental to Russian River Estuary (Estuary) water level management and monitoring...

2010-04-06

344

Iron isotope fractionation in subterranean estuaries  

NASA Astrophysics Data System (ADS)

Dissolved Fe concentrations in subterranean estuaries, like their river-seawater counterparts, are strongly controlled by non-conservative behavior during mixing of groundwater and seawater in coastal aquifers. Previous studies at a subterranean estuary of Waquoit Bay on Cape Cod, USA demonstrate extensive precipitation of groundwater-borne dissolved ferrous iron and subsequent accumulation of iron oxides onto subsurface sands. Waquoit Bay is thus an excellent natural laboratory to assess the mechanisms of Fe-isotope fractionation in redox-stratified environments and determine potential Fe-isotope signatures of groundwater sources to coastal seawater. Here, we report Fe isotope compositions of iron-coated sands and porewaters beneath the intertidal zone of Waquoit Bay. The distribution of pore water Fe shows two distinct sources of Fe: one residing in the upward rising plume of Fe-rich groundwater and the second in the salt-wedge zone of pore water. The groundwater source has high Fe(II) concentration consistent with anoxic conditions and yield ?56Fe values between 0.3 and -1.3‰. In contrast, sediment porewaters occurring in the mixing zone of the subterranean estuary have very low ?56Fe values down to -5‰. These low ?56Fe values reflect Fe-redox cycling and result from the preferential retention of heavy Fe-isotopes onto newly formed Fe-oxyhydroxides. Analysis of Fe-oxides precipitated onto subsurface sands in two cores from the subterranean estuary revealed strong ?56Fe and Fe concentration gradients over less than 2m, yielding an overall range of ?56Fe values between -2 and 1.5‰. The relationship between Fe concentration and ?56Fe of Fe-rich sands can be modeled by the progressive precipitation of Fe-oxides along fluid flow through the subterranean estuary. These results demonstrate that large-scale Fe isotope fractionation (up to 5‰) can occur in subterranean estuaries, which could lead to coastal seawater characterized by very low ?56Fe values relative to river values.

Rouxel, Olivier; Sholkovitz, Edward; Charette, Matthew; Edwards, Katrina J.

2008-07-01

345

Lawrence Livermore National Laboratory Surface Water Protection: A Watershed Approach.  

National Technical Information Service (NTIS)

This surface water protection plan (plan) provides an overview of the management efforts implemented at Lawrence Livermore National Laboratory (LLNL) that support a watershed approach to protect surface water. This plan fulfills a requirement in the Depar...

J. Coty

2009-01-01

346

Seasonal stratification and property distributions in a tropical estuary (Cochin estuary, west coast, India)  

NASA Astrophysics Data System (ADS)

The intratidal, spring-neap and seasonal variations in stratification were examined in the Cochin estuary. The observations established a strong connection with the distribution of chemical and biological properties. The influence of tides and river discharge forcing in water column stability was quantified using potential energy anomaly (PEA) and stratification parameter. Partially mixed (neap) and well-mixed (spring) conditions during low river discharge (dry) period were altered in monsoon by the salt wedge intrusions. The ecological impact of salt wedge propagation on high tides bringing upwelled water to the system was evident from the bottom hypoxic, high chlorophyll a and nutrient-rich conditions. Phosphate and nitrite concentrations were higher at the bottom saline conditions but silicate and nitrate were clearly supplied by river water. However, during ebb tide this front was driven out of the estuary. The periodic advance and retreat of the salt wedge was inevitable in making the system immune from extended hypoxia/anoxia and maintaining the health of the Cochin estuary. For the seasonally varying river flow in the estuary, salt intrusion receded with increasing river flow in monsoon and rebounded with decreasing river flow in dry season. During monsoon, the intense flushing and reduction in salinity field expansion seemed to be responsible for the limited chlorophyll a levels along the surface of the Cochin estuary.

Shivaprasad, A.; Vinita, J.; Revichandran, C.; Reny, P. D.; Deepak, M. P.; Muraleedharan, K. R.; Naveen Kumar, K. R.

2013-01-01

347

Along-estuary dissolved oxygen variability in the Coos Bay estuary, Oregon, USA  

NASA Astrophysics Data System (ADS)

Hypoxia and anoxia are direct threats to the ecosystem and economic health of coastal communities. In estuaries, oceanic and terrestrial systems merge, making their relative influences on water properties such as dissolved oxygen (DO) difficult to tease apart. Recent studies show evidence for low DO conditions occurring on the Oregon shelf during the dry season on temporal and spatial scales unprecedented in the historic record. There is evidence now, too, showing that estuarine hypoxia, historically observed as a product mainly of terrestrial influences, is occurring due to the shifting properties of oceanic inputs. We report here on data collected in the Coos Bay estuary located on the southern Oregon coast, to quantify past and present DO levels to determine if hypoxia is occurring. We use monthly along-estuary sections of temperature, salinity, dissolved oxygen, turbidity, and fluorescence to examine the seasonal cycle of water properties. This data will be put into temporal context through analysis of historic data collected by state, federal, and private organizations. The goal is to link patterns in DO variation to the temporal and spatial circulation of water within the estuary. We show a significant along-estuary gradient in DO and discuss the variability of this gradient in time, over both seasonal and interannual scales.

O'Neill, M.; Sutherland, D.

2013-12-01

348

Annual environmental monitoring report of the Lawrence Berkeley Laboratory  

SciTech Connect

The Lawrence Berkeley Laboratory (LBL) is a multiprogram national laboratory managed by the University of California (UC) for the US Department of Energy (DOE). LBL's major role is to conduct basic and applied science research that is appropriate for an energy research laboratory. The Environmental Monitoring Program of the Lawrence Berkeley Laboratory is described. Data for 1989 are presented, and general trends are discussed. 17 refs., 12 figs., 23 tabs.

Schleimer, G.E.; Pauer, R.O. (eds.)

1990-08-01

349

Modelling Pb and Cd dynamics in the Seine estuary  

Microsoft Academic Search

The Seine estuary (France) is currently one of the world’s most contaminated estuaries, due in particular to its high cadmium\\u000a and lead content. Proper understanding of contaminant transfer, transformation and retention mechanisms throughout the estuary\\u000a and up to the adjacent marine zone require a range of studies involving data collections, experiments, and modeling tool.\\u000a A multivariable transport model (SiAM-3D) was

B. Thouvenin; J. L. Gonzalez; J. F. Chiffoleau; B. Boutier; P. Le Hir

2007-01-01

350

Driving forces and management strategies for estuaries in northern China  

Microsoft Academic Search

Estuaries, which lie at the end of rivers, belong to the interlocking area between marine ecosystems and terrestrial ecosystems.\\u000a In the estuary region, there are plenty of biological resources that carry many important ecosystem services. However, severe\\u000a degradation of the estuary ecosystem in northern China has been caused by anthropogenic disturbances, including water pollution\\u000a from upstream area, change of marine

Anning Suo; Dongzhi Zhao; Fengshou Zhang; Huaru Wang; Fengqiao Liu

2010-01-01

351

Sources of Heavy Metal Pollution into the St. Louis River, Lake Superior Watershed  

NASA Astrophysics Data System (ADS)

The St. Louis River begins in Hoyt Lakes, Minnesota and enters Lake Superior between Duluth, Minnesota and Superior, Wisconsin. The Partridge River and the Embarrass River are two of its main tributaries. National Pollutant Discharge Elimination System (NPDES) permits are issued for surface water dischargers under the Clean Water Act. The Permit Compliance System (PCS) and the Integrated Compliance Information System (ICIS) is a tool allowing public access to information contained in NPDES permits. Along the way to Lake Superior, 19 facilities list the St. Louis River, St. Louis Bay, part of the St. Louis River estuary, or one of its tributaries as a receiving water. Of these 19 locations, four report discharging heavy metals into the receiving water. Copper and Lead are the metals most frequently discharged.

Sternberg, S. P.; Palokangas, C.

2013-12-01

352

Ryan ST Sportplane  

NASA Technical Reports Server (NTRS)

Ryan ST (STA Special): The sporty Ryan ST was flown at Langley Memorial Aeronautical Laboratory in research conducted concerning flaps, slats, and internally-balanced ailerons. 'NACA 96' ended its flying career as a familiarization aircraft for new pilots on the NACA staff. In December 1944, it became NACA 125 and was transferred to the Loads Lab located in the West Area.

1938-01-01

353

21st Century Scholars  

ERIC Educational Resources Information Center

Bethpage Union Free School District in New York is a high-performing district by almost any current accountability measure. Yet administrators and teachers worried that they were not doing enough to prepare their students as critical thinkers for the 21st century. Inspired by the curriculum framework of the Partnership for 21st Century Skills, the…

Clark, Terrence

2009-01-01

354

Recent geomorphic changes in the Liaohe Estuary  

Microsoft Academic Search

This paper mainly analyzes the geomorphological changes of the tidal deposition in the Liaohe Estuary based on the multi-year\\u000a bathymetric charts in 1990, 1996, 2002 and 2005 and Landsat TM images in 1987, 1994, 2002 and 2005. Evolution of the tidal\\u000a depositional system during the past 20 years in the Liaohe River was studied on the basis of 50 boreholes

Longhai Zhu; Jianzheng Wu; Yongchen Xu; Rijun Hu; Nan Wang

2010-01-01

355

Impact of climate change on Gironde Estuary  

NASA Astrophysics Data System (ADS)

Within the THESEUS European project, a simplified mathematical model for storm surge levels in the Bay of Biscay was adjusted on 10 events at Le Verdon using wind and pressure fields from CLM/SGA, so that the water levels at Le Verdon have the same statistic quantiles as observed tide records for the period [1960-2000]. The analysis of future storm surge levels shows a decrease in their quantiles at Le Verdon, whereas there is an increase of the quantiles of total water levels. This increase is smaller than the sea level rise and gets even smaller as one enters farther upstream in the estuary. A numerical model of the Gironde Estuary was then used to evaluate future water levels at 6 locations of the estuary from Le Verdon to Bordeaux and to assess the changes in the quantiles of water levels during the XXIst century using ONERC's pessimistic scenario for sea level rise (60 cm). The model was fed by several data sources : wind fields at Royan and Mérignac interpolated from the grid of the European Climatolologic Model CLM/SGA, a tide signal at Le Verdon, the discharges of Garonne (at La Réole), the Dordogne (at Pessac) and Isle (at Libourne). A series of flood maps for different return periods between 2 and 100 years and for four time periods ([1960-1999], [2010-2039], [2040-2069] and [2070-2099]) have been built for the region of Bordeaux. Quantiles of water levels in the floodplain have also been calculated. The impact of climate change on the evolution of flooded areas in the Gironde Estuary and on quantiles of water levels in the floodplain mainly depends on the sea level rise. Areas which are not currently flooded for low return periods will be inundated in 2100. The influence of river discharges and dike breaching should also be taken into account for more accurate results.

Laborie, Vanessya; Hissel, François; Sergent, Philippe

2014-05-01

356

Obituary: Fred Lawrence Whipple, 1906-2004  

NASA Astrophysics Data System (ADS)

Fred Whipple, one of the founding fathers of planetary science, died on August 30, 2004 just two months shy of his 98th birthday. The breadth of Fred's published research from 1927 through 2000 is quite extraordinary. Although his collected works were published in two massive volumes in 1972, shortly before his retirement, Fred's research contributions continued for another three decades - and another volume is planned. Fred Lawrence Whipple was born on November 5, 1906 on a farm in Red Oak Iowa. His parents were Harry Lawrence and Celestia (MacFarl) Whipple. At the age of fifteen, the Whipple family moved to California where Fred studied mathematics at Occidental College and the University of California at Los Angeles. As a graduate student at the University of California at Berkeley in 1930, he was one of the first to compute an orbit for the newly discovered planet Pluto. Upon receiving his PhD in 1931, he joined the staff of the Harvard College Observatory. He was Chairman of the Harvard Department of Astronomy (1949 - 1956), Director or the Smithsonian Astrophysical Observatory (1955 - 1973), Phillips Professor of Astronomy (1968 - 1977) and Emeritus Phillips Professor of astronomy (1977 - 2004). In 1928 he married Dorothy Woods and their son, Earle Raymond, survives him. The marriage ended in divorce in 1935. Eleven years later, he married Babette F. Samelson and she too survives him, as do their two daughters Laura and (Dorothy) Sandra. Shortly after arriving at Harvard in the early 1930's, Fred developed a photographic tracking network to determine meteor trajectories from simultaneous observations from two or more stations. The photographic trails, chopped by a rotating shutter, allowed their orbits in space to be determined accurately. With the strong involvement of Richard McCrosky and others, he concluded in the early 1960's that most of these meteors were on comet-like orbits and less than 1% of the naked eye, sporadic meteors could be traced to an origin outside the solar system. To fill the daytime gap when meteors could not be photographed, Fred organized a program for the radio detection of these objects. With the launch of Sputnik in October 1957, Whipple's visual network of amateur astronomers (Moon watch) was already in place to follow its progress and later on he developed an optical tracking system for meteors and artificial satellites using wide field, Baker-Nunn cameras. This latter system proved so successful that the precision tracking of these satellites could be used to model the Earth's shape and density variations from the observed gravitational effects upon these satellite orbits. He once noted that the highlight of his career was having his family and parents present at the White House while he received the President's Award for Distinguished Public Service from John F. Kennedy for this work. His seminal works in 1950-51 on the icy conglomerate model for the cometary nucleus prompted a complete paradigm switch. Until then, the current consensus model for a comet was a flying cloud of particles; it had been so since the second half of the nineteenth century when comets were identified with meteor showers. He envisaged the cometary nucleus as a conglomerate of ices (mostly water, ammonia, methane, carbon dioxide and carbon monoxide ices) embedded within, and covered over with, a nonvolatile matrix of meteoric material. Part of his rationale for developing this "dirty snowball" model for the cometary nucleus was to provide an explanation of the so-called nongravitational forces acting upon comets. The rocket-like thrusting of a comet when the ices vaporize near the sun introduced a small, but noticeable, thrust on the comet itself and when this effect was properly modeled, the motions of active comets could be predicted far more accurately. Subsequent spacecraft ultraviolet observations showing enormous cometary hydrogen atmospheres confirmed that the major cometary ice was likely to be water. The 1986 Giotto spacecraft images, revealing a solid cometary nucleus (albeit far blacker

Yeomans, Donald Keith

2004-12-01

357

Resilience of Splittail in the Sacramento–San Joaquin Estuary  

Microsoft Academic Search

Splittail Pogonichthys macrolepidotus, an endemic cyprinid of the Sacramento–San Joaquin estuary, has been proposed for listing as threatened under the U.S. Endangered Species Act. Almost continuous low outflow conditions in the estuary from 1987 to 1994 led to reduced abundance of young splittails, but adult abundance did not decline consistently except in the downstream portion of the species' range. This

Ted Sommer; Randall Baxter; Bruce Herbold

1997-01-01

358

INDEX OF ESTUARINE BENTHIC INTEGRITY FOR GULF OF MEXICO ESTUARIES  

EPA Science Inventory

A benthic index for northern Gulf of Mexico estuaries has been developed and successfully validated by the Environmental Monitoring and Assessment Program for Estuaries (EMAP-E) in the Louisianian Province. The benthic index is a useful indicator of estuarine condition that provi...

359

Geochemistry of trace metals in the Gironde estuary  

Microsoft Academic Search

Using clean techniques, we measured the dissolved, particulate, and (by cross-flow filtration) colloidal fractions of Cd, Ni, Zn, Cu, Pb, Mn, and Fe in the Gironde, an estuary in southwestern France. The fractions of the particulate riverine metals that are apparently mobilized in the estuary vary from >90% for Cd to less than 2% for Pb. Observed mid-salinity maxima for

Anne M. L. Kraepiel; J JEAN-FRANCOIS CHIFFOLEAU; Jean-Marie Martin; François M. M. Morel

1997-01-01

360

LOWER COLUMBIA RIVER ESTUARY PROGRAM COMPREHENSIVE CONSERVATION AND MANAGEMENT PLAN  

EPA Science Inventory

An estuary is the area where the fresh water of a river meets the salt water of an ocean. In the Columbia River system, this occurs in the lower 46 river miles. In an estuary, the river has a direct, natural connection with the open sea. This transition from fresh to salt water c...

361

ASSESSING THE ECOLOGICAL CONDITION OF SOUTHEAST U. S. ESTUARIES  

EPA Science Inventory

As a means to assess ecological condition, 151 stations located in southeastern estuaries from Cape Henry, Virginia to Biscayne Bay, Florida were sampled by state agencies during the summer of 2000 using a probabilistic design. The design used 8 size classes of estuaries ranging ...

362

Life-history styles of fishes in South African estuaries  

Microsoft Academic Search

Fish utilizing South African estuaries may be divided into two major groups according to the location of their spawning sites. The marine group comprises large species which spawn at sea, enter estuaries mainly as juveniles, and return to the sea prior to attaining sexual maturity. The estuarine group is dominated by small species which have the ability to complete their

Alan K. Whitfield

1990-01-01

363

Fate of methane in the Hudson River and estuary  

Microsoft Academic Search

Methane (CH4) concentrations and oxidation rates were measured throughout the Hudson River Estuary in March and August of 1991. Methane concentrations ranged from 50 to 940 nM and were supersaturated with respect to the atmosphere along the entire length of the river, with generally higher CH4 values in the lower, saline portion of the estuary. A seasonally averaged diffusive flux

Marie A. de Angelis; Mary I. Scranton

1993-01-01

364

Eelgrass Distribution in the Great Bay Estuary 2008. Final Report.  

National Technical Information Service (NTIS)

Eelgrass in the Great Bay Estuary in 2008 was found only in the Great Bay itself and Portsmouth Harbor. In 2008 there was a continued loss of eelgrass biomass in the Estuary. Virtually all the eelgrass in Little Bay and the Piscataqua River has died. Eelg...

F. Short

2009-01-01

365

LIMNETIC LARVAL FISH OF THE MAUMEE AND SANDUSKY RIVER ESTUARIES  

EPA Science Inventory

A total of 17 taxa were collected in the Maumee River estuary during sampling periods in 1975, 1976, and 1977. A total of 11 taxa were collected from the Sandusky River estuary in 1976. Gizzard shad/alewife, Dorosoma cepedianum/Alosa pseudoharengus, white bass/white perch, Morone...

366

The Hydrography of the Chupa Estuary, White Sea, Russia  

Microsoft Academic Search

This study was undertaken to determine the fate and fluxes of materials from Arctic estuaries to the coastal zone. The paper is the first of a series addressing questions relating to the physics and chemistry of the region. Three seasonal cruises were undertaken in the Chupa Estuary, White Sea, Russia; in summer (July 1994), autumn (September, 1995) and spring (May\\/June

R. J. M. Howland; A. N. Pantiulin; G. E. Millward; R. Prego

1999-01-01

367

Behavior of metals in the Amur River estuary  

Microsoft Academic Search

Biogeochemical processes in estuaries determine to a significant extent the further life of chemical compounds, including metals transported by rivers. Therefore, the characteristics of the behavior of metals in waters with intermediate salinity at the river?sea interface have both scientific and practical significance [1?5]. In terms of estimation of the concentrations of dissolved metals, the estuary of the Amur River,

V. M. Shul’kin

2006-01-01

368

St. Paul's Cathedral  

NSDL National Science Digital Library

Perhaps one of the finest neo-Classical cathedrals in the world, the current St. Paul's cathedral is an example of the outstanding architecture of Christopher Wren, and a testimony to his dogged persistence and passion for his life's work. In keeping with the attention to detail that is indicative of Mr. Wren's work, the St. Paul's Web site has detailed information on visiting the cathedral, the various musical performances that it hosts, and an interactive timeline detailing the history of St. Paul's that extends back to the year 604. Along with this information, the site also tells visitors about upcoming events at the cathedral, along with an extensive online gift shop that offers a diverse set of St. Paul's related material for purchase.

369

St.Louis  

Cancer.gov

Skip to Main Content Headlines Pediatric Oncology Branch Home > Pediatric Psycho-Oncology Professionals > Training Headline Title Pediatric Psycho-Oncology Professionals Pediatric Psychologist, Hem/Onc St. Louis Children's Hospital The Psychology Department

370

Lawrence Livermore National Laboratory Annual Report 2006  

SciTech Connect

For the Laboratory and staff, 2006 was a year of outstanding achievements. As our many accomplishments in this annual report illustrate, the Laboratory's focus on important problems that affect our nation's security and our researchers breakthroughs in science and technology have led to major successes. As a national laboratory that is part of the Department of Energy's National Nuclear Security Administration (DOE/NNSA), Livermore is a key contributor to the Stockpile Stewardship Program for maintaining the safety, security, and reliability of the nation's nuclear weapons stockpile. The program has been highly successful, and our annual report features some of the Laboratory's significant stockpile stewardship accomplishments in 2006. A notable example is a long-term study with Los Alamos National Laboratory, which found that weapon pit performance will not sharply degrade from the aging effects on plutonium. The conclusion was based on a wide range of nonnuclear experiments, detailed simulations, theoretical advances, and thorough analyses of the results of past nuclear tests. The study was a superb scientific effort. The continuing success of stockpile stewardship enabled NNSA in 2006 to lay out Complex 2030, a vision for a transformed nuclear weapons complex that is more responsive, cost efficient, and highly secure. One of the ways our Laboratory will help lead this transformation is through the design and development of reliable replacement warheads (RRWs). Compared to current designs, these warheads would have enhanced performance margins and security features and would be less costly to manufacture and maintain in a smaller, modernized production complex. In early 2007, NNSA selected Lawrence Livermore and Sandia National Laboratories-California to develop ''RRW-1'' for the U.S. Navy. Design efforts for the RRW, the plutonium aging work, and many other stockpile stewardship accomplishments rely on computer simulations performed on NNSA's Advanced Simulation and Computing (ASC) Program supercomputers at Livermore. ASC Purple and BlueGene/L, the world's fastest computer, together provide nearly a half petaflop (500 trillion operations per second) of computer power for use by the three NNSA national laboratories. Livermore-led teams were awarded the Gordon Bell Prize for Peak Performance in both 2005 and 2006. The winning simulations, run on BlueGene/L, investigated the properties of materials at the length and time scales of atomic interactions. The computing power that makes possible such detailed simulations provides unprecedented opportunities for scientific discovery. Laboratory scientists are meeting the extraordinary challenge of creating experimental capabilities to match the resolution of supercomputer simulations. Working with a wide range of collaborators, we are developing experimental tools that gather better data at the nanometer and subnanosecond scales. Applications range from imaging biomolecules to studying matter at extreme conditions of pressure and temperature. The premier high-energy-density experimental physics facility in the world will be the National Ignition Facility (NIF) when construction is completed in 2009. We are leading the national effort to perform the first fusion ignition experiments using NIF's 192-beam laser and prepare to explore some of the remaining important issues in weapons physics. With scientific colleagues from throughout the nation, we are also designing revolutionary experiments on NIF to advance the fields of astrophysics, planetary physics, and materials science. Mission-directed, multidisciplinary science and technology at Livermore is also focused on reducing the threat posed by the proliferation of weapons of mass destruction as well as their acquisition and use by terrorists. The Laboratory helps this important national effort by providing its unique expertise, integration analyses, and operational support to the Department of Homeland Security. For this vital facet of the Laboratory's national security mission, we are developing advanced technologies, such as

Chrzanowski, P; Walter, K

2007-05-24

371

Approaches for Development of Nutrient Criteria in Oregon Estuaries With a Focus on Tillamook Estuary  

EPA Science Inventory

Development of nutrient criteria for all water body types of the US remains a top priority for EPA. Estuaries in the Pacific Northwest receive nutrients from both the watershed and the coastal ocean, and thus are particularly complex systems in which to establish water quality c...

372

Post-glacial sedimentary evolution of a microtidal estuary, Dyfi Estuary, west Wales, U.K.  

NASA Astrophysics Data System (ADS)

The,Dyfi Estuary is a microtidal estuary located on the shores of Cardigan Bay on the west coast of Wales. The inundation of the post-glacial sea-level rise has produced transgressive muddy or silly, late-glacial and post-glacial unconsolidated sediments in the pre-existing valley. These sediments are complicated by sea-level fluctuations and changes in tidal range. Modern facies-distribution patterns and sedimentary characteristics, extensive core data, and chronostratigraphic cross-sections provide a detailed history of the post-glacial sedimentary evolution of the Dyfi Estuary. The post-glacial estuarine evolution of the Dyfi Estuary has been subdivided into four phases. Phase 1: 15,000-10,000 yr BP, shallow-water, high-energy fluvially dominated facies. Phase 2: 10,000-6,000 yr BP, deep-water, low-energy, estuarine dominated facies. Phase 3: 6,000-3,500 yr BP, shallow-water, high-energy, tidally dominated facies. Phase 4: 3,500 yr BP-present, shallow-water, low-energy, estuarine salt-marshes dominated facies.

Shi, Zhong; Lamb, H. F.

1991-10-01

373

The behavior of trace metals in the Geum Estuary, Korea  

SciTech Connect

The distributions of trace metals in the Geum Estuary of western Korea were studied with regard to changes in other estuarine chemical parameters. Dissolved oxygen, pH, and alkalinity increased with increasing salinity. Dissolved aluminum concentrations increased at low salinities and were perhaps influenced by the solubility of particulate aluminosilicate phases. Iron, manganese, cobalt, and zinc are removed from solution in the low salinity end of the estuary. Cobalt and nickel have mid-estuary concentration maxima that may be due to an anthropogenic source. Cadmium, copper, lead, and zinc concentrations also increased in the estuary, possibly as th result of remobilization in the sediments. Cadmium increases are also linked to remineralization from tidal flat sediments in the outer estuary. The source of an increase in dissolved lead at low salinity is unclear, but may be due to release from particles.

Byrd, J.T.; Smith, R.G.; Windom, H.L. (Skidaway Inst. of Oceanography, Savannah, GA (United States)); Lee, Kwang, W. (Hanyang Univ. Ansan, Kyunggi (Korea)); Lee, Dong, S. (Korea Ocean Research and Development Inst., Ansan, Kyunggi (Korea))

1991-05-01

374

Delaware Estuary Situation Reports: Emergency Response. How Do Emergency Management Officials Address Disasters in the Delaware Estuary.  

National Technical Information Service (NTIS)

From hurricanes and other natural threats to oil spills and other 'manmade' emergencies, the Delaware Estuary has experienced a variety of disasters over the years. The toll that these events take on the estuary and those who live on its shores depends la...

R. T. Sylves

1991-01-01

375

AN APPROACH TO DEVELOPING NUTRIENT CRITERIA FOR PACIFIC NORTHWEST ESTUARIES: A CASE STUDY OF YAQUINA ESTUARY, OREGON  

EPA Science Inventory

NHEERL scientists have developed an approach that could be used by the State of Oregon for development of nutrient and other water quality criteria for the Yaquina Estuary, Oregon. The principle objective in setting protective criteria is to prevent future degradation of estuari...

376

SENSITIVITY OF NITROGEN CONCENTRATIONS IN ESTUARIES TO LOADING AND WATER RESIDENCE TIME: APPLICATION TO THE POTOMAC ESTUARY  

EPA Science Inventory

We use a simple nitrogen budget model to analyze concentrations of total nitrogen (TN) in estuaries for which both nitrogen inputs and water residence time are correlated with freshwater inflow rates. While the nitrogen concentration of an estuary varies linearly with TN loading ...

377

MAIA Estuaries 1997-98 Data  

NSDL National Science Digital Library

The Mid Atlantic Integrated Assessment program (MAIA) of the Environmental Protection Agency (EPA) has released these estuaries data for 1997-98. Data and Metadata may be viewed or downloaded (text or .pdf) for the following variables: Sampling Station Location Data, Station Visit Data, Water Quality Physical Measurements, Water Quality- Nutrients Data, Sediment Grain Size Data, Sediment Toxicity Data, Sediment Chemistry Data, Benthic Community Grain Size Data, Benthic Abundance Data, Benthic Biomass Data, Benthic Community Summary Data, Chemical Analyte Code Table, and Benthic Taxon Code Table.

378

Structure and Function of South-east Australian Estuaries  

NASA Astrophysics Data System (ADS)

An attempt is made to synthesize the geological properties, water quality attributes and aspects of the ecology of south-east Australian estuaries so as to provide a framework for addressing coastal management issues. The approach is based on the underlying causal factors of geology and morphology and more immediate environmental factors (e.g. salinity and sediments) which are associated with ecological distributions, species richness and fisheries catch. This ' broad brush ' approach seeks to maximize reality and generality, albeit at the expense of precision and local variability in individual circumstances. It disregards small-scale ecological patterns as noise. Unlike in the Northern Hemisphere, conditions in temperate Australia are characterized by irregular flood and fire regimes that strongly influence estuary hydrology and nutrient inputs. Three main types of estuary (tide-dominated, wave-dominated and intermittently closed) are recognized based on geological criteria and having particular entrance conditions that control tidal exchange. Four zones (marine flood-tidal delta, central mud basin, fluvial delta and riverine channel/alluvial plain) are also recognized common to each type of estuary. These zones correspond to mappable sedimentary environments in all estuaries and have characteristic water quality, nutrient cycling/primary productivity signatures and ecosystems. The ecology of a zone is modified by (a) estuary type which determines the salinity regime; (b) stage of sediment filling (evolutionary maturity) which controls the spatial distribution/size of the zones; and (c) impacts of various forms of development. By using the zones/habitats as a common currency among all estuaries, it is possible to link ecological aspects such as species richness and commercial fisheries production so as to compare different estuaries or within-estuary zones.

Roy, P. S.; Williams, R. J.; Jones, A. R.; Yassini, I.; Gibbs, P. J.; Coates, B.; West, R. J.; Scanes, P. R.; Hudson, J. P.; Nichol, S.

2001-09-01

379

Management of hazardous wastes Lawrence Livermore National Laboratory  

SciTech Connect

Lawrence Livermore National Laboratory (LLNL), during the course of numerous research activities, generates hazardous, radioactive, and mixed (radioactive and hazardous) wastes. The management of these waste materials is highly regulated in the United States (US). This paper focuses on the hazardous waste regulations that limit and prescribe waste management at LLNL.

Jackson, C.S.

1993-11-01

380

Astronaut Wendy Lawrence participates in training session in the CCT  

NASA Technical Reports Server (NTRS)

Seated in the pilot's seat of a JSC Shuttle trainer, astronaut Wendy B. Lawrence, STS-67 flight engineer, participates in a training session. The 1992 astronaut class graduate is in the crew compartment trainer (CCT) of JSC's Shuttle mockup and integration laboratory.

1994-01-01

381

Copyright in the Balance: LJ Talks with Lawrence Lessig.  

ERIC Educational Resources Information Center

Discusses copyright issues of interest to librarians with Lawrence Lessig, a legal scholar on copyright, technology, and the Constitution. Topics include Eldred v. Ashcroft; copyright extensions; balancing interests of copyright owners with future creators and the public; privacy, fair use, and public domain; and the Digital Millennium Copyright…

Albanese, Andrew Richard

2002-01-01

382

Energy and Technology Review, November 1991. [Lawrence Livermore National Laboratory  

Microsoft Academic Search

The Lawrence Livermore National Laboratory, operated by the University of California for the United States Department of Energy, was established in 1952 to do research on nuclear weapons and magnetic fusion energy. Since, then we have added other major programs, including laser fusion and laser isotope separation, biomedical and environmental science, strategic defense, and applied energy technology. These programs, in

J. A. Sefcik; L. de Vore; K. Gleason; H. Kroopnick; N. M. Sanford

1991-01-01

383

Annual environmental monitoring report of the Lawrence Berkeley Laboratory, 1986  

SciTech Connect

The Environmental Monitoring Program of the Lawrence Berkeley Laboratory is described. Data for 1986 are presented and general trends are discussed. Topics include radiation monitoring, wastewater discharge monitoring, dose distribution estimates, and ground water monitoring. 9 refs., 8 figs., 20 tabs.

Schleimer, G.E. (ed.)

1987-04-01

384

Waste management study: Process development at Lawrence Livermore National Laboratory  

SciTech Connect

This report presents the results of an evaluation of the present Toxic Waste Control Operations at the Lawrence Livermore National Laboratory, evaluates the technologies most applicable to the treatment of toxic and hazardous wastes and presents conceptual designs of processes for the installation of a new decontamination and waste treatment facility (DWTF) for future treatment of these wastes.

Not Available

1984-12-01

385

Lawrence Berkeley National Laboratory 1995 site environmental report  

Microsoft Academic Search

The 1995 Site Environmental Report summarizes environmental activities at the Ernest Orlando Lawrence Berkeley National Laboratory (LBNL) for the 1995 calendar year. The report strives to present environmental data in a manner that characterizes the performance and compliance status of the environmental management programs. The report also discusses significant highlights and plans of these programs. Topics discussed include: environmental monitoring,

D. Balgobin; I. Javandel; G. Lackner; C. Smith; P. Thorson; H. Tran

1996-01-01

386

Lawrence Livermore National Laboratory (LLNL) research on cold fusion  

Microsoft Academic Search

With the appearance of reports on Cold Fusion, scientists at the Lawrence Livermore National Laboratory (LLNL) began a series of increasingly sophisticated experiments and calculations to explain these phenomena. These experiments can be categorized as follows: (1) simple experiments to replicate the Utah results, (2) more sophisticated experiments to place lower bounds on the generation of heat and production of

K. I. Thomassen; J. F. Holzrichter; F. T. Aldridge; B. Balke; J. Bowers; D. B. Bullen; M. D. Cable; M. Caffee; R. B. Campbell; C. Colmenares

1989-01-01

387

LLNL (Lawrence Livermore National Laboratory) research on cold fusion  

Microsoft Academic Search

With the appearance of reports on Cold Fusion,'' scientists at the Lawrence Livermore National Laboratory (LLNL) began a series of increasingly sophisticated experiments and calculations to explain these phenomena. These experiments can be categorized as follows: (a) simple experiments to replicate the Utah results, (b) more sophisticated experiments to place lower bounds on the generation of heat and production of

K. I. Thomassen; J. F. Holzrichter

1989-01-01

388

LAWRENCE AVENUE UNDERFLOW SEWER SYSTEM: MONITORING AND EVALUATION  

EPA Science Inventory

A new and bold concept in design of urban drainage systems was developed as a step forward in the solution of combined sewer overflow problems. A deep tunnel in bed rock about 200 to 250 feet (61 to 76 m) below the surface was designed and constructed for the Lawrence Avenue drai...

389

LAWRENCE AVENUE UNDERFLOW SEWER SYSTEM. INTERIM REPORT: PLANNING AND CONSTRUCTION  

EPA Science Inventory

A new and bold concept in design of urban drainage systems was developed as a step forward in the solution of combined sewer overflow problems. A deep tunnel in bed rock about 200 to 250 feet (61 to 76 m) below the surface was designed and constructed for the Lawrence Avenue drai...

390

Sediment Transport Processes In River Dominated Sub-Tropical Estuaries  

NASA Astrophysics Data System (ADS)

The objective of this study is to present a comparative assessment of the largest three river dominated estuaries in the southern coast of the state of Santa Catarina, Brazil (Tubarão, Araranguá and Mampituba estuaries). The study was focused on mechanisms of transport of suspended sediments influenced by its morphologic and hydrodynamics characteristics. As shown in D'Aquino et al (2011), these estuaries share common attributes (climate and tides) and follow the basic conceptual model of fine sediment transport (presented by Toldo & Schettini (2006). However, each one has its own particularities regarding the geographical setting, land use, hypsometry, outfall, etc. The methodology used to the field measurements was the same for all estuaries, aiming at measuring the currents, water level, salinity, temperature and turbidity near the outfall for at least two complete tidal cycles (~25 hours). All the campaigns were carried on under syzygya tide conditions. During the sample collecting period, a longitudinal profile was conducted in each estuary, through acquisitions of salinity and temperature of the water column in every kilometer. In the Tubarão and Araranguá rivers estuaries, the concentration of suspended particulate matter (SPM) is mostly influenced by the periods of incoming tide, flood currents. In the Mampituba river estuary, the flocculation process was observed during the encounter of fresh and salt water in every tide entrance. It was possible to observe that the Araranguá river estuary, in what concerns the bottom SPM, responds to the variation of salinity and currents along the bottom. The Tubarão estuary presents a relation between the salinity and the bottom currents. In the Mampituba estuary no relevant correlation was found between the SPM, the salinity, and the bottom currents. Those aspects demonstrate that even sharing some characteristics there are significant differences among these estuaries. In addition, as a result of the comparative study, an analytical model was proposed that correlates the fluvial discharge, salt wedge, and SPM. This model might represent a tool to encourage discussions and help the scientific exploration of the estuaries in the south of Santa Catarina.

DAquino, Carla; Schettini, Carlos

2014-05-01

391

Forest bound estuaries are higher methane emitters than paddy fields: A case of Godavari estuary, East Coast of India  

NASA Astrophysics Data System (ADS)

In the Godavari estuary, ambient methane concentrations were monitored for a period of 5 years and the data reveals that the estuary sampling stations have shown a high average maximum value of methane 14.8 ppmv while nearby paddy field sampling stations the methane concentration were 3-4 fold lower than the estuary. The acidic nature of the estuary soils (pH 5.8-6.2) along with redox potential -120mV favours high methane emissions. The samples collected from the edge of the estuary have shown 0.12-0.15% of Fe wherein ambient methane concentrations were 4.8-5.6 ppmv. It was observed that the anoxic condition with high available iron in the soil improves anaerobic decomposition of organic matter to produce methane. The litter production from nearby mangrove vegetation in the estuary is approximately 22,000 tons/annum is a causative factor for higher methane emissions. Remote sensing data was used and developed thematic maps for spatial and temporal distribution of methane using geographical information system. The seasonal trend showed high ambient concentration of methane in winter season, which is mainly due to high moisture content, (OH?) radical and lower temperature. The results suggest that high organic matter (2.5-4.2%) along with soil conditions in the estuary are influencing for higher methane emissions, while in paddy fields the available organic matter for methanogenesis is limited.

Krupadam, Reddithota J.; Ahuja, Rashmi; Wate, Satish R.; Anjaneyulu, Yerramilli

392

Estuary/ocean exchange and tidal mixing in a Gulf of Maine Estuary: A Lagrangian modeling study  

NASA Astrophysics Data System (ADS)

A Lagrangian particle method embedded within a 2-D finite element code, is used to study the transport and ocean-estuary exchange processes in the well-mixed Great Bay Estuarine System in New Hampshire, USA. The 2-D finite element model, driven by residual, semi-diurnal and diurnal tidal constituents, includes the effects of wetting and drying of estuarine mud flats through the use of a porous medium transport module. The particle method includes tidal advection, plus a random walk model in the horizontal that simulates sub-grid scale turbulent transport processes. Our approach involves instantaneous, massive [O(500,000)] particle releases that enable the quantification of ocean-estuary and inter-bay exchanges in a Markovian framework. The effects of the release time, spring-neap cycle, riverine discharge and diffusion strength on the intra-estuary and estuary-ocean exchange are also investigated. The results show a rather dynamic interaction between the ocean and the estuary with a fraction of the exiting particles being caught up in the Gulf of Maine Coastal Current and swept away. Three somewhat different estimates of estuarine residence time are calculated to provide complementary views of estuary flushing. Maps of residence time versus release location uncover a strong spatial dependency of residence time within the estuary that has very important ramifications for local water quality. Simulations with and without the turbulent random walk show that the combined effect of advective shear and turbulent diffusion is very effective at spreading particles throughout the estuary relatively quickly, even at low (1 m 2/s) diffusivity. The results presented here show that a first-order Markov Chain approach has applicability and a high potential for improving our understanding of the mixing processes in estuaries.

Bilgili, Ata; Proehl, Jeffrey A.; Lynch, Daniel R.; Smith, Keston W.; Swift, M. Robinson

2005-12-01

393

The Spectra of Somatic Mutations Across Many Tumor Types - Michael Lawrence, TCGA Scientific Symposium 2011  

Cancer.gov

Home News and Events Multimedia Library Videos The Spectra of Somatic Mutations Across Many Tumor Types - Michael Lawrence The Spectra of Somatic Mutations Across Many Tumor Types - Michael Lawrence, TCGA Scientific Symposium 2011 You will need Adobe

394

Catalog of Research Abstracts, 1993: Partnership opportunities at Lawrence Berkeley Laboratory.  

National Technical Information Service (NTIS)

The 1993 edition of Lawrence Berkeley Laboratory's Catalog of Research Abstracts is a comprehensive listing of ongoing research projects in LBL's ten research divisions. Lawrence Berkeley Laboratory (LBL) is a major multi-program national laboratory manag...

1993-01-01

395

From "Lawrence Kohlberg's Approach to Moral Education" by F. Clark Power, Ann Higgins, and Lawrence Kohlberg, with Judy Codding (1989)  

ERIC Educational Resources Information Center

This article is an excerpt from "Lawrence Kohlberg's Approach to Moral Education." It refers several times to Kohlberg's "six stages of moral development." Stages 3 and 4 belong to the second level of moral development, which Kohlberg calls "conventional." At stage 3, one becomes aware of conventions as one sees what is right in terms of living up…

Schools: Studies in Education, 2011

2011-01-01

396

Use of the USEPA Estuary Nitrogen Model to Estimate Concentrations of Total Nitrogen in Estuaries Using Loads Calculated by Watershed Models and Monitoring Data  

EPA Science Inventory

We use USEPA?s Estuary Nitrogen Model (ENM) to calculate annual average concentrations of total nitrogen (TN) in ten estuaries or sub-estuaries along the Atlantic coast from New Hampshire to Florida. These include a variety of systems, ranging from strongly-flushed bays to weakly...

397

Climate Change and the Delaware Estuary: Three Case Studies in Vulnerability Assessment and Adaptation Planning.Partnership for the Delaware Estuary.  

National Technical Information Service (NTIS)

The Delaware Estuary watershed and its natural resources will face a variety of challenges with climate change. Due to the many unique features of the Estuary, some aspects of changing climate may not be as severe here as in nearby watersheds and estuarie...

D. Kreeger D. Velinsky J. Adkins P. Cole R. Najjar

2010-01-01

398

Mt. St. Helens Memories.  

ERIC Educational Resources Information Center

Provides a personal account of one science teacher's participation in a teacher workshop in which teachers learned about volcanic development, types of eruption, geomorphology, plate tectonics, volcano monitoring, and hazards created by volcanoes by examining Mt. St. Helens. Provides a graphic identifying volcanoes active since 1975. (MDH)

Sharp, Len

1992-01-01

399

The St. Louis Motor  

ERIC Educational Resources Information Center

The St. Louis Motor, invented in 1909, is unique among physics apparatus for being named for a geographical place rather than a physicist. The sturdy little device (Fig. 1) has never been out of production. Any older school or physics department that has not done a catastrophic housecleaning in the last 20 years will certainly have a small flock…

Greenslade, Thomas B., Jr.

2011-01-01

400

St. Louis Children's Hospital  

Cancer.gov

The Psychology Department of St. Louis Children’s Hospital at Washington University Medical Center is pleased to announce 2 Postdoctoral Fellowship positions in Pediatric Psychology beginning September 2014. With a balance of in-depth and broad based training experiences, this one-year program will prepare fellows to work independently in the practice of pediatric psychology.

401

75 FR 69622 - Request for Comments on the Draft Revision of the Estuary Habitat Restoration Strategy Prepared...  

Federal Register 2010, 2011, 2012, 2013

...Draft Revision of the Estuary Habitat Restoration Strategy Prepared by the Estuary Habitat Restoration Council AGENCY: National Marine Fisheries...behalf of the interagency Estuary Habitat Restoration Council, is soliciting comments on...

2010-11-15

402

A Slowly - Varying Conservative Transport Model for Shallow Estuaries.  

National Technical Information Service (NTIS)

The development and application of a two-dimensional long-term dynamic numerical transport model which is capable of describing the spatial and temporal slowly-varying distributions of conservative constituents in shallow, well-mixed estuaries is presente...

R. J. Brandes F. D. Masch

1971-01-01

403

Assessing the Impact of Human Activities on British Columbia's Estuaries  

PubMed Central

The world’s marine and coastal ecosystems are under threat and single-sector management efforts have failed to address those threats. Scientific consensus suggests that management should evolve to focus on ecosystems and their human, ecological, and physical components. Estuaries are recognized globally as one of the world’s most productive and most threatened ecosystems and many estuarine areas in British Columbia (BC) have been lost or degraded. To help prioritize activities and areas for regional management efforts, spatial information on human activities that adversely affect BC’s estuaries was compiled. Using statistical analyses, estuaries were assigned to groups facing related threats that could benefit from similar management. The results show that estuaries in the most populated marine ecosections have the highest biological importance but also the highest impacts and the lowest levels of protection. This research is timely, as it will inform ongoing marine planning, land acquisition, and stewardship efforts in BC.

Robb, Carolyn K.

2014-01-01

404

Landscape Thresholds and the Condition of Northeastern Estuaries  

EPA Science Inventory

Anthropogenic impacts to northeastern estuaries have been well documented and many researchers have quantified the associations between broad scale human land uses in contributing landscapes and impacted estuarine condition. However, associations alone are not adequate for ident...

405

FRESHWATER INFLOWS: WATER FOR HEALTHY ESTUARIES CONFERENCE (MX96476507  

EPA Science Inventory

The grantee will hold an interstate workshop on Freshwater Inflow issues in the Gulf of Mexico coastal region. The conference will identify water management questions to be addressed regarding providing freshwater inflows to estuaries, update participants on the current scientif...

406

Evaluating Causes of Ecological Impairments in the Estuaries of Ukraine  

EPA Science Inventory

Ukrainian estuaries have not undergone a systematic evaluation of the causes of ecological impairments caused by anthropogenic contamination. The objective of this evaluation is to use recently developed diagnostic tools to determine the causes of benthic ecological impairments. ...

407

HIGH CYANOBACTERIAL ABUNDANCE IN GULF OF MEXICO ESTUARIES  

EPA Science Inventory

Aquatic phytoplankton comprise a wide variety of taxa spanning more than 2 orders of magnitude in size, yet studies of estuarine phytoplankton often overlook the picoplankton, particularly chroococcoid cyanobacteria (c.f. Synechocococcus). Three Gulf of Mexico estuaries (Apalachi...

408

Guidelines for determining inputs of inorganic contaminants into estuaries.  

National Technical Information Service (NTIS)

This publication describes sampling and sample preparation procedures suitable to obtain unpolluted samples for the purpose of determining river inputs of inorganic pollutants into estuaries. Emphasis is placed on heavy metal pollutants but procedures are...

1987-01-01

409

CASCO BAY ESTUARY PROJECT TRIENNIAL IMPLEMENTATION REVIEW MARCH, 2004  

EPA Science Inventory

The Casco Bay Estuary Project has seven primary goals/priorities which include: minimize pollutant loading from stormwater; open and protect shellfish beds; protect and restore habitat; reduce toxic pollution; promote responsible stewardship; sustain and promote the continued eff...

410

BACTERIOPLANKTON DYNAMICS IN A SUBTROPICAL ESTUARY: EVIDENCE FOR SUBSTRATE LIMITATION  

EPA Science Inventory

Bacterioplankton abundance and metabolic characteristics were measured along a transect in Pensacola Bay, Florida, USA, to examine the factors that control microbial water column processes in this subtropical estuary. The microbial measures included 3 H-L-leucine incorporation, e...

411

SPATIAL DISTRIBUTIONS OF BURROWING SHRIMP POPULATIONS IN TWO OREGON ESTUARIES  

EPA Science Inventory

Thalassinid burrowing shrimp (Neotrypaea californiensis and Upogebia pugettensis) inhabit large expanses of Pacific estuarine tide flats, from British Columbia to Baja California. The spatial distribution of shrimp populations within estuaries has rarely been quantified because ...

412

Biogeochemistry of the Kem' River estuary, White Sea (Russia)  

Microsoft Academic Search

The biogeochemistry of the river-sea interface was studied in the Kem' River (the largest river flowing to the White Sea from Karelian coast) estuary and adjacent area of the White Sea onboard the RV \\

V. R. Shevchenko; Y. S. Dolotov; N. N. Filatov; T. N. Alexeeva; A. S. Filippov; E.-M. Nöthig; A. N. Novigatsky; L. A. Pautova; A. V. Platonov; N. V. Politova; T. N. Rat'kova; R. Stein

2005-01-01

413

Continuous resistivity profiling data from the Corsica River Estuary, Maryland  

USGS Publications Warehouse

Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine its importance in nutrient delivery to the Chesapeake Bay. The Corsica River Estuary represents a coastal lowland setting typical of much of the eastern bay. An interdisciplinary U.S. Geological Survey (USGS) science team conducted field operations in the lower estuary in April and May 2007. Resource managers are concerned about nutrients that are entering the estuary via SGD that may be contributing to eutrophication, harmful algal blooms, and fish kills. Techniques employed in the study included continuous resistivity profiling (CRP), piezometer sampling of submarine groundwater, and collection of a time series of radon tracer activity in surface water. A CRP system measures electrical resistivity of saturated subestuarine sediments to distinguish those bearing fresh water (high resistivity) from those with saline or brackish pore water (low resistivity). This report describes the collection and processing of CRP data and summarizes the results. Based on a grid of 67.6 kilometers of CRP data, low-salinity (high-resistivity) groundwater extended approximately 50-400 meters offshore from estuary shorelines at depths of 5 to >12 meters below the sediment surface, likely beneath a confining unit. A band of low-resistivity sediment detected along the axis of the estuary indicated the presence of a filled paleochannel containing brackish groundwater. The meandering paleochannel likely incised through the confining unit during periods of lower sea level, allowing the low-salinity groundwater plumes originating from land to mix with brackish subestuarine groundwater along the channel margins and to discharge. A better understanding of the spatial variability and geological controls of submarine groundwater flow beneath the Corsica River Estuary could lead to improved models and mitigation strategies for nutrient over-enrichment in the estuary and in other similar settings.

Cross, V.A.; Bratton, J.F.; Worley, C.R.; Crusius, J.; Kroeger, K.D.

2011-01-01

414

Status of Splittail in the Sacramento–San Joaquin Estuary  

Microsoft Academic Search

Analysis of data from four extensive fish surveys in the Sacramento–San Joaquin estuary indicated that splittail Pogonichthys macrolepidotus, endemic to the Central Valley of California, declined by 62% over a 13-year period. Splittails are now found mostly in the estuary, a fraction of their former range. In a gill-net survey in August 1994, 50% of the splittails taken in the

Lesa Meng; Peter B. Moyle

1995-01-01

415

Sediment transport by streams draining into the Delaware Estuary  

USGS Publications Warehouse

The quantity of sediment transported by streams draining into the Delaware estuary from Pennsylvania, New Jersey, and Delaware varies areally according to geology, physiography, and land use. Of the estimated total sediment load of 1.6 million tons entering the Delaware estuary annually, about 48 percent is contributed by the Delaware River main stem at Trenton, NJ; 34 percent by Pennsylvania tributaries; and 18 percent by New Jersey and Delaware tributaries.

Mansue, Lawrence J.; Commings, Allen B.

1974-01-01

416

Distribution and Transport of Chemical Constituents in the Clyde Estuary  

NASA Astrophysics Data System (ADS)

Five transects of the Clyde Estuary were carried out between August 1989 and March 1991, always during the last 2 h of the flood tide. The following water-column properties were examined: dissolved, leachable particulate and detrital particulate trace elements (Fe, Mn, Zn, Pb, Cd, Co, Cu, Ni), pH, alkalinity, salinity, temperature, dissolved oxygen, dissolved and particulate organic carbon, suspended particulate matter and dissolved nutrients (PO 4, NH 3 + NH 4, NO 3, NO 2, Si). The distribution patterns for both dissolved metals and nutrients reflected their quasi-conservative behaviour in the lower estuary, but were more difficult to interpret in the upper estuary due to the multiplicity of inputs. The suspended particulate material (SPM) collected in the lower estuary at 3 m was depleted in leachable Fe, Zn, Cd, Co, Cu, Ni, and enriched in leachable Mn and Pb relative to the upper estuary. For Mn, the degree of enrichment increased towards the mouth of the estuary, and also with decreasing 'effective freshwater input', indicating that the oxidation of Mn(II) proceeds outside the estuary (Firth of Clyde) and to an extent dependent on the residence time of water in that coastal sea area. The quasi-conservative behaviour of most dissolved and particulate constituents within the estuary results from a combination of short residence time (3-7 days) and low SPM (2-10 mg l -1). This behaviour makes it possible to estimate their net seaward fluxes before these become modified by the processes of coagulation (Fe), sorption (Zn, Pb, Co) and oxidative precipitation (Mn) operating in the Firth of Clyde. The seaward fluxes of NH 4 + NH 3, NO 2, PO 4, dissolved Mn, particulate Fe, Zn and Cu are approximately constant throughout the year. Other dissolved and particulate metal fluxes are best represented by an increasing function of freshwater discharge, although the large residual variability attests to the greater complexity of input functions for trace metals.

Muller, F. L. L.; Tranter, M.; Balls, P. W.

1994-08-01

417

The role of salt marshes in the Mira estuary (Portugal)  

Microsoft Academic Search

The Mira estuary is a narrow entrenched pristine estuary of the Ria type, about 30 km long. It comprises an area of 285 ha\\u000a of salt marsh, of which250 ha have been proposed for reclamation for aquaculture. Dredging, village and recreation development\\u000a menace the yet undisturbed estuarine ecosystem. To assess the biological importance of this wetland, a multidisciplinary study\\u000a was

M. J. Costa; Fernando Catarino; Alexandre Bettencourt

2001-01-01

418

Sediment transport and trapping in the Hudson River estuary  

Microsoft Academic Search

The Hudson River estuary has a pronounced turbidity maximum zone, in which rapid, short-term deposition of sediment occurs\\u000a during and following the spring freshet. Water-column measurements of currents and suspended sediment were performed during\\u000a the spring of 1999 to determine the rate and mechanisms of sediment transport and trapping in the estuary. The net convergence\\u000a of sediment in the lower

W. Rockwell Geyer; Jonathan D. Woodruff; Peter Traykovski

2001-01-01

419

Attenuation of rare earth elements in a boreal estuary  

NASA Astrophysics Data System (ADS)

This study focuses on attenuation of rare earth elements (REE) when a boreal creek, acidified and loaded with REE and other metals as a result of wetland drainage, empties into a brackish-water estuary (salinity < 6‰). Surface water was collected in a transect from the creek mouth to the outer estuary, and settling (particulate) material in sediment traps moored at selected locations in the estuary. Ultrafiltration, high-resolution ICP-MS and modeling were applied on the waters, and a variety of chemical reagents were used to extract metals from the settling material. Aluminium, Fe and REE transported by the acidic creek were extensively removed in the inner/central estuary where the acidic water was neutralised, whereas Mn was relatively persistent in solution and thus redistributed to particles and deposited further down the estuary. The REE removal was caused by several contemporary mechanisms: co-precipitation with oxyhydroxides (mainly Al but also Fe), complexation with flocculating humic substances and sorption to suspended particles. Down estuary the dissolved REE pool, remaining after removal, was fractionated: the <1 kDa pool became depleted in the middle REE and the colloidal (0.45 ?m-1 kDa) pool depleted in the middle and heavy REE. This fractionation was controlled by the removal process, such that those REE with highest affinity for the settling particles became most depleted in the remaining dissolved pool. Modeling, based on Visual MINTEQ version 3.0 and the Stockholm Humic Model after revision and updating, predicted that the dissolved (<0.45 ?m) REE pool in the estuary is bound almost entirely to humic substances. Acid sulphate soils, the source of the REE and other metals in the creek water, are widespread on coastal plains worldwide and therefore the REE attenuation patterns and mechanisms identified in the studied estuary are relevant for recognition of similar geochemical processes and conditions in a variety of coastal locations.

Åström, Mats E.; Österholm, Peter; Gustafsson, Jon Petter; Nystrand, Miriam; Peltola, Pasi; Nordmyr, Linda; Boman, Anton

2012-11-01

420

Conservation of Thane Creek and Ulhas River Estuary, India.  

PubMed

There has been a steady decrease in the area occupied by wetlands in creeks and estuaries adjacent urban areas due to unprecedented urban growth in coastal cities, for example, Thane Creek and Ulhas River Estuary near Mumbai, India. Urban cities serve as centres of employment and attract a large number of migrants from other places. In case of coastal cities, due to inadequate infrastructure, wastewater and solid waste are disposed of into wetlands and estuary. Discharge of sediments and solid waste into the creeks from drains and construction activities has resulted in decreased flow depth in the coastal waters of Thane Creek and Ulhas River Estuary. Various researchers have studied individual elements of Thane Creek and Ulhas River Estuary at micro level. However, a holistic approach for restoration and conservation of the creek and estuary is required. This paper presents the details of an integrated approach incorporating different conservation measures such as sewerage and sewage treatment, urban drainage management, solid waste management, mangrove plantation and dredging. PMID:21117428

Nikam, Vinay S; Kumar, Arun; Lalla, Kamal; Gupta, Kapil

2009-07-01

421

Winds and the orientation of a coastal plane estuary plume  

NASA Astrophysics Data System (ADS)

Based on a calibrated coastal plane estuary plume model, ideal model hindcasts of estuary plumes are used to describe the evolution of the plume pattern in response to river discharge and local wind forcing by selecting a typical partially mixed estuary (the Cape Fear River Estuary or CFRE). With the help of an existing calibrated plume model, as described by Xia et al. (2007), simulations were conducted using different parameters to evaluate the plume behavior type and its change associated with the variation of wind forcing and river discharge. The simulations indicate that relatively moderate winds can mechanically reverse the flow direction of the plume. Downwelling favorably wind will pin the plume to the coasts while the upwelling plume could induce plume from the left side to right side in the application to CFRE. It was found that six major types of plumes may occur in the estuary and in the corresponding coastal ocean. To better understand these plumes in the CFRE and other similar river estuary systems, we also investigated how the plumes transition from one type to another. Results showed that wind direction, wind speed, and sometimes river discharge contribute to plume transitions.

Xia, Meng; Xie, Lian; Pietrafesa, Leonard J.

2010-10-01

422

Identifying 21st Century Capabilities  

ERIC Educational Resources Information Center

What are the capabilities necessary to meet 21st century challenges? Much of the literature on 21st century skills focuses on skills necessary to meet those challenges associated with future work in a globalised world. The result is a limited characterisation of those capabilities necessary to address 21st century social, health and particularly…

Stevens, Robert

2012-01-01

423

SCALIA’S SHIP OF REVULSION HAS SAILED: WILL LAWRENCE PROTECT ADULTS WHO ADOPT LOVERS TO HELP ENSURE THEIR INHERITANCE FROM INCEST PROSECUTION?  

Microsoft Academic Search

SCALIA’S SHIP OF REVULSION HAS SAILED: WILL LAWRENCE PROTECT ADULTS WHO ADOPT LOVERS TO HELP ENSURE THEIR INHERITANCE FROM INCEST PROSECUTION?\\u000aTerry L. Turnipseed\\u000aAssociate Professor of Law\\u000aSyracuse University College of Law\\u000ain•cest (?n's?st') Sexual relations between family members or close relatives, including children related by adoption.\\u000aThere is a growing trend in this country – startling to many

Terry L. Turnipseed

2008-01-01

424

SPACE/TIME ANALYSIS OF FECAL POLLUTION AND RAINFALL IN AN EASTERN NORTH CAROLINA ESTUARY  

PubMed Central

The Newport River Estuary (NPRE) is a high priority shellfish harvesting area in eastern North Carolina (NC) that is impaired due to fecal contamination, specifically exceeding recommended levels for fecal coliforms. A hydrologic-driven mean trend model was developed, as a function of antecedent rainfall, in the NPRE to predict levels of E. coli (EC, measured as a proxy for fecal coliforms). This mean trend model was integrated in a Bayesian Maximum Entropy (BME) framework to produce informative Space/Time (S/T) maps depicting fecal contamination across the NPRE during winter and summer months. These maps showed that during dry winter months, corresponding to the oyster harvesting season in NC (October 1st to March 30th), predicted EC concentrations were below the shellfish harvesting standard (14 MPN per 100 ml). However, after substantial rainfall 3.81 cm (1.5 inches), the NPRE did not appear to meet this requirement. Warmer months resulted in the predicted EC concentrations exceeding the threshold for the NPRE. Predicted ENT concentrations were generally below the recreational water quality threshold (104 MPN per 100 ml), except for warmer months after substantial rainfall. Once established, this combined approach produces near real-time visual information on which to base water quality management decisions.

Coulliette, Angela D.; Money, Eric S.; Serre, Marc L.; Noble, Rachel T.

2009-01-01

425

Industrial ecology at Lawrence Livermore National Laboratory summary statement  

SciTech Connect

This statement summarizes Lawrence Livermore National Laboratory`s committment to making important scientific, technological, and business contributions to global sustainability. The quest has many aspects, some socio-political or economic and some technological, and some in which the soft and hard sciences become indistinguishable, as in visionary national strategies, like Holland`s, and futuristic regional and city development plans, like those of Kagoshima and Chattanooga.

Gilmartin, T.J.

1996-05-21

426

Astronomy applications of adaptive optics at Lawrence Livermore National Laboratory  

NASA Astrophysics Data System (ADS)

Astronomical applications of adaptive optics at Lawrence Livermore National Laboratory (LLNL) has a history that extends from 1984. The program started with the Lick Observatory Adaptive Optics system and has progressed through the years to lever-larger telescopes: Keck, and now the proposed CELT (California Extremely Large Telescope) 30m telescope. LLNL AO continues to be at the forefront of AO development and science.

Bauman, Brian J.; Gavel, Donald T.

2003-06-01

427

Annual site environmental report of the Lawrence Berkeley Laboratory  

SciTech Connect

The Environmental Monitoring Program of the Lawrence Berkeley Laboratory is described. Data for 1990 are presented, and general trends are discussed. The report is organized under the following topics: Environmental Program Overview; Environmental Permits; Environmental Assessments; Environmental Activities; Penetrating Radiation; Airborne Radionuclides; Waterborne Radionuclides; Public Doses Resulting from LBL Operations; Trends -- LBL Environmental Impact; Waterborne Pollutants; Airborne Pollutants; Groundwater Protection; and Quality Assurance. 20 refs., 26 figs., 23 tabs.

Schleimer, G.E.; Pauer, R.O. (eds.)

1991-05-01

428

Guide to user facilities at the Lawrence Berkeley Laboratory  

SciTech Connect

Lawrence Berkeley Laboratories' user facilities are described. Specific facilities include: the National Center for Electron Microscopy; the Bevalac; the SuperHILAC; the Neutral Beam Engineering Test Facility; the National Tritium Labeling Facility; the 88 inch Cyclotron; the Heavy Charged-Particle Treatment Facility; the 2.5 MeV Van de Graaff; the Sky Simulator; the Center for Computational Seismology; and the Low Background Counting Facility. (GHT)

Not Available

1984-04-01

429

Making Sense of the Senseless: The Murder of Lawrence King  

ERIC Educational Resources Information Center

On Feb. 12, 2008, 15-year-old Lawrence King was shot twice in the head in front of other students, in Oxnard, California. When Larry King was murdered allegedly due to a classmate's prejudice, some pundits asked if adults were to blame for encouraging him to come out. One can't be sure what adults did or didn't do in this case, but the question…

Reis, Beth

2008-01-01

430

Center for accelerator mass spectrometry Lawrence Livermore National Laboratory  

Microsoft Academic Search

The Center for Accelerator Mass Spectrometry (CAMS) at Lawrence Livermore National Laboratory (LLNL) is a multi-disciplinary research organization that conducts both technological and applications research. CAMS operates both an HVEC FN tandem and a NEC Model 5SDH-2 tandem accelerator. Using highly sensitive accelerator-based element and isotope detection methods, staff at CAMS collaborate with a broad scope of external and internal

M. L. Roberts; J. R. Southon; I. D. Proctor

1997-01-01

431

Replanting St. Helens  

SciTech Connect

On May 18, 1980 an earthquake beneath the north side of Mt. St. Helens triggered the eruption of this volcano. This eruption caused damage to 160,000 acres of forests, meadows, lakes and streams. This paper discussed the reforestation of approximately 50,000 acres of devastated land which was located around the site of the eruption. It also discussed the natural recovery of this area and the reestablishment of ecosystems and rebuilding of habitats by the plants and animals.

Holbrook, J.J.

1986-05-01

432

The St. Louis Motor  

NASA Astrophysics Data System (ADS)

The St. Louis Motor, invented in 1909, is unique among physics apparatus for being named for a geographical place rather than a physicist. The sturdy little device (Fig. 1) has never been out of production. Any older school or physics department that has not done a catastrophic housecleaning in the last 20 years will certainly have a small flock of them in the back room.

Greenslade, Thomas B.

2011-10-01

433

Lawrence's Legacy : Seaborg's Cyclotron - The 88-Inch Cyclotron turns 40  

NASA Astrophysics Data System (ADS)

In 1958, Sputnik had recently been launched by the Russians, leading to worry in Congress and increased funding for science and technology. Ernest Lawrence was director of the "Rad Lab" at Berkeley. Another Nobel Prize winner, Glenn Seaborg, was Associate Laboratory Director and Director of the Nuclear Chemistry Division. In this atmosphere, Lawrence was phoned by commissioners of the Atomic Energy Commission and asked what they could do for Seaborg, "because he did such a fine job of setting up the chemistry for extracting plutonium from spent reactor fuel" [1]. In this informal way, the 90-Inch (eventually 88-Inch) Cyclotron became a line item in the federal budget at a cost of 3M (later increased to 5M). The 88-Inch Cyclotron achieved first internal beam on Dec. 12, 1961 and first external beam in May 1962. Forty years later it is still going strong. Pieced together from interviews with the retirees who built it, Rad Lab reports and archives from the Seaborg and Lawrence collections, the story of its design and construction - on-time and under-budget - provides a glimpse into the early days of big science. [1] remarks made by Elmer Kelly, "Physicist-in-charge' of the project on the occasion of the 40th anniversary celebration.

McMahan, Margaret; Clark, David

2003-04-01

434

A hydrologic and geomorphic model of estuary breaching and closure  

NASA Astrophysics Data System (ADS)

To better understand how the hydrology of bar-built estuaries affects breaching and closing patterns, a model is developed that incorporates an estuary hydrologic budget with a geomorphic model of the inlet system. Erosion of the inlet is caused by inlet flow, whereas the only morphologic effect of waves is the deposition of sand into the inlet. When calibrated, the model is able to reproduce the initial seasonal breaching, seasonal closure, intermittent closures and breaches, and the low-streamflow (closed state) estuary hydrology of the Carmel Lagoon, located in Central California. Model performance was tested against three separate years of water-level observations. When open during these years, the inlet was visually observed to drain directly across the beach berm, in accordance with model assumptions. The calibrated model predicts the observed 48-h estuary stage amplitude with root mean square errors of 0.45 m, 0.39 m and 0.42 m for the three separate years. For the calibrated model, the probability that the estuary inlet is closed decreases exponentially with increasing inflow (streamflow plus wave overtopping), decreasing 10-fold in probability as mean daily inflow increases from 0.2 to 1.0 m3/s. Seasonal patterns of inlet state reflect the seasonal pattern of streamflow, though wave overtopping may become the main hydrologic flux during low streamflow conditions, infrequently causing short-lived breaches. In a series of sensitivity analyses it is seen that the status of the inlet and storage of water are sensitive to factors that control the storage, transmission, and inflow of water. By varying individual components of the berm system and estuary storage, the amount of the time the estuary is open may increase by 57%, or decrease by 44%, compared to the amount of time the estuary is open during calibrated model conditions for the 18.2-year model period. The individual components tested are: berm height, width, length, and hydraulic conductivity; estuary hypsometry (storage to stage relationship); two factors that control wave-swash sedimentation of the inlet; and sea level rise. The elevation of the berm determines the volume of water that must enter the estuary in order to breach, and it modulates the wave-overtopping flux and frequency. By increasing estuary storage capacity, the estuary will breach less frequently (- 27% change in time open for modeled excavation scenario) and store water up to 3 months later into the summer. Altering beach aquifer hydraulic conductivity affects inlet state, and patterns of breaching and water storage. As a result of sea-level rise of 1.67 m by 2100, and a beach berm that remains in its current location and accretes vertically, the amount of time the estuary remains open may decrease by 44%. Such a change is an end-member of likely scenarios given that the berm will translate landwards. Model results indicate that the amount of time the estuary is open is more sensitive to changes in wave run-up than the amount of sand deposited in the inlet per each overtopping wave.

Rich, Andrew; Keller, Edward A.

2013-06-01

435

33 CFR 165.1190 - Security Zone; San Francisco Bay, Oakland Estuary, Alameda, CA.  

Code of Federal Regulations, 2013 CFR

...Security Zone; San Francisco Bay, Oakland Estuary, Alameda, CA. 165.1190 Section 165.1190 Navigation and Navigable...Security Zone; San Francisco Bay, Oakland Estuary, Alameda, CA. (a) Location. The following area is a security zone:...

2013-07-01

436

CLASSIFYING OREGON ESTUARIES BY HABITAT: ANALYSIS OF EXISTING DATA AND A PROPOSAL FOR A PILOT STUDY  

EPA Science Inventory

Because many estuarine resources are linked to benthic habitats, classification of estuaries by habitat types may prove a relevant approach for grouping estuaries with similar ecological values and vulnerability to landscape alterations. As a first step, we evaluated whether pub...

437

Potential Climate-Induced Runoff Changes and Associated Uncertainty in Four Pacific Northwest Estuaries.  

National Technical Information Service (NTIS)

As part of a larger investigation into potential effects of climate change on estuarine habitats in the Pacific Northwest, we estimated changes in freshwater inputs into four estuaries: Coquille River estuary, South Slough of Coos Bay, and Yaquina Bay in ...

C. A. Brown D. A. Reusser H. Chang I. W. Jung M. O. Steele

2012-01-01

438

A DATA SYSTEM FOR INTEGRATING DATA FROM LANDSCAPES, STREAMS AND ESTUARIES  

EPA Science Inventory

Estuaries are natural integrators of substances and processes that occur internally and externally (watersheds, ocean, atmosphere). Watershed activities that contribute fresh water, nutrients, contaminants, and suspended solids have a strong effect on the health of estuaries. Res...

439

Hydrodynamic controls on oxygen dynamics in a riverine salt wedge estuary, the Yarra River estuary, Australia  

NASA Astrophysics Data System (ADS)

Oxygen depletion in coastal and estuarine waters has been increasing rapidly around the globe over the past several decades, leading to decline in water quality and ecological health. In this study we apply a numerical model to understand how salt wedge dynamics, changes in river flow and temperature together control oxygen depletion in a micro-tidal riverine estuary, the Yarra River estuary, Australia. Coupled physical-biogeochemical models have been previously applied to study how hydrodynamics impact upon seasonal hypoxia; however, their application to relatively shallow, narrow riverine estuaries with highly transient patterns of river inputs and sporadic periods of oxygen depletion has remained challenging, largely due to difficulty in accurately simulating salt wedge dynamics in morphologically complex areas. In this study we overcome this issue through application of a flexible mesh 3-D hydrodynamic-biogeochemical model in order to predict the extent of salt wedge intrusion and consequent patterns of oxygen depletion. The extent of the salt wedge responded quickly to the sporadic riverine flows, with the strength of stratification and vertical density gradients heavily influenced by morphological features corresponding to shallow points in regions of tight curvature ("horseshoe" bends). The spatiotemporal patterns of stratification led to the emergence of two "hot spots" of anoxia, the first downstream of a shallow region of tight curvature and the second downstream of a sill. Whilst these areas corresponded to regions of intense stratification, it was found that antecedent conditions related to the placement of the salt wedge played a major role in the recovery of anoxic regions following episodic high flow events. Furthermore, whilst a threshold salt wedge intrusion was a requirement for oxygen depletion, analysis of the results allowed us to quantify the effect of temperature in determining the overall severity and extent of hypoxia and anoxia. Climate warming scenarios highlighted that oxygen depletion is likely to be exacerbated through changes in flow regimes and warming temperatures; however, the increasing risk of hypoxia and anoxia can be mitigated through management of minimum flow allocations and targeted reductions in organic matter loading. A simple statistical model (R2 > 0.65) is suggested to relate riverine flow and temperature to the extent of estuary-wide anoxia.

Bruce, L. C.; Cook, P. L. M.; Teakle, I.; Hipsey, M. R.

2014-04-01

440

Impact of Recent Constraints on Intellectual Freedom on Science and Technology at Lawrence Livermore National Laboratory  

SciTech Connect

The Lawrence Livermore National Laboratory (LLNL) was created in 1952 to meet the nation's need for an expanded nuclear weapons research and development (R&D) capability. LLNL quickly grew to become a full-fledged nuclear weapons design laboratory with a broad range of technical capabilities similar to those of our sister laboratory--Los Alamos--with which we shared mission responsibilities. By its very nature, nuclear weapons R&D requires some of the most advanced science and technology (S&T). Accordingly, there is an obvious need for careful attention to ensure that appropriate security measures exist to deal with the sensitive aspects of nuclear weapons development. The trade-off between advancing S&T at the Laboratory and the need for security is a complex issue that has always been with us, As Edward Teller noted in a recent commentary in a May, 1999 editorial in the New York Times: ''The reaction of President Harry Truman to the leaking of information is well known. He imposed no additional measures for security. Instead, we have clear knowledge that the disclosures by (Klaus) Fuchs caused Truman to call for accelerated work on all aspects of nuclear weapons. The right prescription for safety is not reaction to dangers that are arising, but rather action leading to more knowledge and, one hopes, toward positive interaction between nations.'' To explore the issue of intellectual freedom at a national security laboratory such as LLNL, one must understand the type of activities we pursue and how our research portfolio has evolved since the Laboratory was established. Our mission affects the workforce skills, capabilities, and security measures that the Laboratory requires. The national security needs of the US have evolved, along with the S&T community in which the Laboratory resides and to which it contributes. These factors give rise to a greater need for the Laboratory to interact with universities, industry, and other national laboratories. Intellectual freedom at the Laboratory and constraints on it can be understood only within the context of our mission, our necessary interactions with other entities; and our need for an exceptional multidisciplinary workforce.

Wadsworth, J

2000-11-12

441

Mount St. Helens Rebirth  

NASA Technical Reports Server (NTRS)

The catastrophic eruption of Mt. St. Helens 20 years ago today (on May 18, 1980), ranks among the most important natural events of the twentieth century in the United States. Because Mt. St. Helens is in a remote area of the Cascades Mountains, only a few people were killed by the eruption, but property damage and destruction totaled in the billions of dollars. Mount St. Helens is an example of a composite or stratovolcano. These are explosive volcanoes that are generally steep-sided, symmetrical cones built up by the accumulation of debris from previous eruptions and consist of alternating layers of lava flows, volcanic ash and cinder. Some of the most photographed mountains in the world are stratovolcanoes, including Mount Fuji in Japan, Mount Cotopaxi in Ecuador, Mount Hood in Oregon, and Mount Rainier in Washington. The recently erupting Mount Usu on the island of Hokkaido in Japan is also a stratovolcano. Stratovolcanoes are characterized by having plumbing systems that move magma from a chamber deep within the Earth's crust to vents at the surface. The height of Mt. St. Helens was reduced from about 2950 m (9677 ft) to about 2550 m (8364 ft) as a result of the explosive eruption on the morning of May 18. The eruption sent a column of dust and ash upwards more than 25 km into the atmosphere, and shock waves from the blast knocked down almost every tree within 10 km of the central crater. Massive avalanches and mudflows, generated by the near-instantaneous melting of deep snowpacks on the flanks of the mountain, devastated an area more than 20 km to the north and east of the former summit, and rivers choked with all sorts of debris were flooded more than 100 km away. The area of almost total destruction was about 600 sq. km. Ash from the eruption cloud was rapidly blown to the northeast and east producing lightning which started many small forest fires. An erie darkness caused by the cloud enveloped the landscape more than 200 km from the blast area, and ash could be seen falling from the sky over the Great Plains, more than 1500 km distant. This image was acquired by Landsat 7 on Aug. 22, 1999. It was produced at 30-m resolution using bands 3, 2, and 1 to display red, green, and blue, respectively ('true color'). Some of the effects of the massive eruption on May 18, 1980, can still be seen clearly, especially on the northern and eastern flanks of Mount St. Helens, which are still mostly barren (shades of white and gray). The crater is in the center of the image. Note the streaking from the crater (gray on the image). These are the remnants of pyroclastic flows (superheated avalanches of gas, ash and pieces of rock) that carved deep channels down the slopes and onto the relatively flat areas near the base of the mountain. The partially-filled Spirit Lake can be seen just to the northeast of the crater (blue-black on the image), and the where most of the energy was directed during the blast is the gray area immediately to the northwest of the crater. However, on other parts of the mountain, the rejuvenation process is obvious. Ash deposits have supplied minerals which have accelerated vegetation growth (various shades of green). Though far from what it looked like 20 years ago, Mount St Helens is actively recovering. Data courtesy Landsat 7 project and EROS Data Center. Caption by James Foster, NASA Goddard Space Flight Center.

2002-01-01

442

Horizontal distribution and population dynamics of the dominant mysid Hyperacanthomysis longirostris along a temperate macrotidal estuary (Chikugo River estuary, Japan)  

NASA Astrophysics Data System (ADS)

The estuarine turbidity maximum (ETM) that develops in the lower salinity areas of macrotidal estuaries has been considered as an important nursery for many fish species. Mysids are one of the dominant organisms in the ETM, serving as a key food source for juvenile fish. To investigate the horizontal distribution and population dynamics of dominant mysids in relation to the fluctuation of physical conditions (temperature, salinity, turbidity, and freshwater discharge), we conducted monthly sampling (hauls of a ring net in the surface water) along the macrotidal Chikugo River estuary in Japan from May 2005 to December 2006. Hyperacanthomysis longirostris was the dominant mysid in the estuary, usually showing peaks of density and biomass in or close to the ETM (salinity 1-10). In addition, intra-specific differences (life-cycle stage, sex, and size) in horizontal distribution were found along the estuary. Larger males and females, particularly gravid females, were distributed upstream from the center of distribution where juveniles were overwhelmingly dominant. Juveniles increased in size toward the sea in marked contrast with males and females. The findings suggest a possible system of population maintenance within the estuary; gravid females release juveniles in the upper estuary, juveniles grow during downstream transport, young males and females mature during the upstream migration. Density and biomass were primarily controlled by seasonal changes of temperature, being high at intermediate temperatures (ca. 15-25 °C in late spring and fall) and being low at the extreme temperatures (ca. 10 °C in midwinter and 30 °C in midsummer). High density (up to 666 ind. m -3) and biomass (up to 168 mg dry weight m -3) of H. longirostris were considered to be comparable with those of copepods in the estuary.

Suzuki, Keita W.; Nakayama, Kouji; Tanaka, Masaru

2009-08-01

443

Sediment balance of intertidal mudflats in a macrotidal estuary  

NASA Astrophysics Data System (ADS)

Intertidal area contributes widely to fine-grained sediment balance in estuarine environments. Their sedimentary dynamics is controlled by several forcing parameters including tidal range, river flow and swell, affected by human activities such as dredging, construction or vessels traffic leading to modify sediment transport pattern. Although the estuarine hydrodynamics is well documented, the link between forcing parameters and these sedimentary processes is weakly understood. One of the main reasons is the difficulty to integrate spatial (from the fluvial to the estuary mouth) and temporal (from swell in seconds to pluriannual river flow variability) patterns. This study achieved on intertidal mudflats distributed along the macrotidal Seine estuary (France) aims (i) to quantify the impact of forcing parameters on each intertidal area respect to its longitudinal position in the estuarine system and (ii) to assess the fine-grained sediment budget at estuarine scale. The Seine estuary is a macrotidal estuary developed over 160 km up the upstream limit of tidal wave penetration. With an average river flow of 450m3.s-1, 80% of the Suspended Particles Matter (SPM) annual flux is discharged during the flood period. In the downstream part, the Seine estuary Turbidity Maximum (TM) is the SPM stock located near the mouth. During their transfer toward the sea, the fine particles can be trapped in (i) the intertidal mudflats; preferential areas characterized by low hydrodynamics and generally sheltered of the tidal dominant flow, the main tidal current the Seine River and (ii) the TM. The Seine estuary is an anthropic estuary in order to secure navigation: one consequence of these developments is the tidal bore disappearance. Along the macrotidal Seine estuary hydrodynamics features and sedimentary fluxes were followed during at least 1 year using respectively Acoustic Doppler Velocimeter, Optical BackScatter and altimeter. Results in the fluvial estuary enhance the role of hydrological cycle that lead to (i) an increased mean water level and (ii) provide SPM from the continental area. This feature leads to significant accretion over intertidal area. In the middle and marine estuary the TM is the main SPM supplier. In these parts of the estuary deposition over these intertidal area is driven by (i) tidal cycle in particular fortnightly cycle link to maximum TM resuspension during (strongest) spring tide and (ii) TM location controlled by river inflow that varies following an annual and inter-annual variability. Outside sedimentation period, the erosion is driven by the combination of (i) progressive erosion driven by fortnightly cycle and (ii) sudden erosion controlled either by wave or boat generated waves respectively at the mouth and in the middle/upper estuary. This last is reinforced by the rheological characteristics of deposit that correspond to fluid/low consolidated mud. During most of the year, the Seine estuary mudflats record an erosion pattern. Significant and intensive sedimentation only occurs few days per year. This pattern is linked to highly variable hydrodynamics conditions (bottom shear stress ranging from 0.5 to 5 N.m-2) that control the sediment supply availability. In this infilling macrotidal anthropized system mudflats are close to equilibrium with an annual rate ranging between +/- 5cm.yrs-1: they act as temporal storage area of fined-grained sediments.

lafite, R.; Deloffre, J.; Lemoine, M.

2012-12-01

444

Observations of Floc Sizes in a Muddy Estuary  

NASA Astrophysics Data System (ADS)

Measurements are presented of median floc diameters and associated environmental data over spring-tide tidal cycles at two stations in the muddy Tamar Estuary, UK, for winter, spring and summer conditions. The particulate organic carbon and particulate total carbon contents of mudflats and SPM (suspended particulate matter) at the stations, together with other evidence, indicates that much of the SPM was derived from mud sources that were located between the two stations during winter and spring, and from very mobile sediment sources in the upper estuary during summer. Observed in-situ median floc sizes varied widely, from <50 to >500 ?m and rapid settling of particles close to HW and LW (high and low water) left only the smaller flocs in suspension. Time-series of depth-averaged median floc sizes generally were most closely, positively, correlated with depth-averaged SPM concentrations. Floc diameters tended to reach maximum median sizes near the time when SPM concentrations were highest. These high concentrations were in turn largely generated by resuspension of sediment during the fastest current speeds. Although such correlations may have arisen because of SPM-driven floc growth - despite fast tidal currents - there is also the possibility that tough aggregates were eroded from the intertidal mudflats and mudbanks. Although a hypothesis, such large aggregates of fine sediment may have resulted from the binding together of very fine bed particles by sticky extracellular polymeric substances (EPS) coatings, produced by benthic diatoms and by other biologically-mediated activity. A rapid reduction of SPM occurred at the up-estuary station within 2.5 h of HW on the flood, when decelerating currents were still relatively fast. It appears that at least two processes were at work: localised settling of the largest flocs and up-estuary transport in which large flocs were transported further into the estuary before settling into the Tamar's ETM (estuarine turbidity maximum) over the HW-slack period. Up-estuary advection of large flocs and their eventual settling would place the down-estuary edge of the ETM above the upper-estuary station during summer, spring-tide conditions. This position of the ETM was observed close to HW during longitudinal surveys of the estuary.

Uncles, R. J.; Bale, A. J.; Stephens, J. A.; Frickers, P. E.; Harris, C.

2010-04-01

445

Population Dynamics and Distribution Patterns of Longfin Smelt in the San Francisco Estuary  

Microsoft Academic Search

The San Francisco Estuary supports several endemic species of fish and the southernmost populations of other species. Many of these native species and populations are imperiled or have experienced recent population declines that indicate a general decline in the estuary's capacity to support pelagic fish species. We studied the distribution and abundance of one of the estuary's native species, longfin

Jonathan A. Rosenfield; Randall D. Baxter

2007-01-01

446

PEER REVIEW OF PECONIC ESTUARY PROGRAM HYDRODYNAMIC AND WATER QUALITY (EUTROPHICATION) MODEL  

EPA Science Inventory

The Peconic Estuary is located on the eastern end of Long Island, New York. Under the Federal Clean Water Act, the Peconic Estuary was named an "Estuary of National Significance" in 1992. Because of its high concentration of rare, threatened and endangered species and habitats,...

447

Sedimentation of river-transported particles in the Öre estuary, northern Sweden  

Microsoft Academic Search

Sedimentation of river transported particles in the Öre Estuary was studied during spring flow (April–May, 1989). River input was calculated as the product of discharge and particle concentration in the river water. The concentration of suspended matter in the estuary water was determined with a light-scattering probe at 25 depth profiles throughout the estuary. The sedimentation was measured using sediment

Louise Malmgren; Lars Brydsten

1992-01-01

448

Man-made radionuclides and sedimentation in the Hudson River Estuary  

Microsoft Academic Search

Recently deposited fine-grained sediments in the Hudson River estuary contain radionuclides from global fallout produced by atmospheric bomb tests as well as from low-level releases of a local nuclear reactor. Accumulation rates of these nuclides are dependent on rates of sediment deposition and vary with location in the estuary by more than two orders of magnitude. Within the Hudson estuary,

H. J. Simpson; C. R. Olsen; R. M. Trier; S. C. Williams

1976-01-01

449

Impact of different tidal renewable energy projects on the hydrodynamic processes in the Severn Estuary, UK  

Microsoft Academic Search

The Severn Estuary, located in the UK between south east Wales and south west England, is an ideal site for tidal renewable energy projects, since this estuary has the third highest tidal range in the world, with a spring tidal range approaching 14m. The UK Government recently invited proposals for tidal renewable energy projects from the estuary and many proposals

Junqiang Xia; Roger A. Falconer; Binliang Lin

2010-01-01

450

A Simple Model of Nitrogen Concentration, Throughput, and Denitrification in Estuaries  

EPA Science Inventory

The Estuary Nitrogen Model (ENM) is a mass balance model that includes calculation of nitrogen losses within bays and estuaries using system flushing time. The model has been used to demonstrate the dependence of throughput and denitrification of nitrogen in bays and estuaries on...

451

Two decades of fish habitat restoration and bioengineering on the Fraser River estuary, British Columbia, Canada  

Microsoft Academic Search

The Fraser River estuary is the most important estuary on Canada's Pacific coast. To achieve a net gain of fish habitat, a goal of Canada's fisheries management policy, a large number of habitat restoration projects have been conducted in the estuary since 1980. In this paper the author focuses on bioengineering aspects of some of the older projects and an

C. D. Levings

2004-01-01