Morphological variation of siscowet lake trout in Lake Superior

USGS Publications Warehouse

Bronte, C.R.; Moore, S.A.

2007-01-01

Historically, Lake Superior has contained many morphologically distinct forms of the lake trout Salvelinus namaycush that have occupied specific depths and locations and spawned at specific times of the year. Today, as was probably the case historically, the siscowet morphotype is the most abundant. Recent interest in harvesting siscowets to extract oil containing omega-3 fatty acids will require additional knowledge of the biology and stock structure of these lightly exploited populations. The objective of this study was to determine whether shape differences exist among siscowet populations across Lake Superior and whether these shape differences can be used to infer stock structure. Morphometric analysis (truss protocol) was used to differentiate among siscowets sampled from 23 locations in Lake Superior. We analyzed 31 distance measurements among 14 anatomical landmarks taken from digital images of fish recorded in the field. Cluster analysis of size-corrected data separated fish into three geographic groups: The Isle Royale, eastern (Michigan), and western regions (Michigan). Finer scales of stock structure were also suggested. Discriminant function analysis demonstrated that head measurements contributed to most of the observed variation. Cross-validation classification rates indicated that 67–71% of individual fish were correctly classified to their region of capture. This is the first study to present shape differences associated with location within a lake trout morphotype in Lake Superior.

Monitoring Land Cover Change in the Lake Superior Basin

EPA Science Inventory

Lake Superior is the largest freshwater lake in the world by area and the third largest by volume. It is also the most pristine of the Great Lakes (Lake Superior Lakewide Management Plan 2006). Even still, Lake Superior is not without its threats ranging from chemical contamina...

STATUS OF MYSIS RELICTA IN LAKE SUPERIOR

EPA Science Inventory

The status of different components of the lower food web is reported for Lake Superior. Results are preliminary summaries from the Binational collaboration in 2005, which measured the lower food web at the request of the Lake Superior Fisheries Technical Committee and Lake Superi...

Modeling nearshore-offshore exchange in Lake Superior

PubMed Central

Tokos, Kathy S.; Matsumoto, Katsumi

2018-01-01

Lake Superior′s ecosystem includes distinct nearshore and offshore food webs linked by hydrodynamic processes that transport water and tracers along and across shore. The scales over which these processes occur and their sensitivity to increasing summer surface temperatures are not well understood. This study investigated horizontal mixing between nearshore and offshore areas of Lake Superior over the 10-year period from 2003 to 2012 using a realistically forced three-dimensional numerical model and virtual tracers. An age tracer was used to characterize the time scales of horizontal mixing between nearshore areas of the lake where water depth is less than 100 m and deeper areas. The age of water in nearshore areas increased and decreased in an annual cycle corresponding to the lake′s dimictic cycle of vertical mixing and stratification. Interannual variability of mixing in the isothermal period was significantly correlated to average springtime wind speed, whereas variability during the stratified season was correlated to the average summer surface temperature. Dispersal of a passive tracer released from nine locations around the model lake’s perimeter was more extensive in late summer when stratification was established lakewide than in early summer. The distribution of eddies resolved in the model reflected differences between the early and late summer dispersal patterns. In the eastern part of the lake dispersal was primarily alongshore, reflecting counterclockwise coastal circulation. In the western part of the lake, cross-shore mixing was enhanced by cross-basin currents. PMID:29447286

Differentiation in Coregonus zenithicus in Lake Superior

USGS Publications Warehouse

Todd, Thomas N.; Smith, Gerald R.

1980-01-01

Morphological variation in Coregonus zenithicus has long plagued biologists working on Lake Superior ciscoes. Some of this variation is due to allometric growth; earlier workers incorrectly recognized large C. zenithicus as a distinct species, C. nigripinnis cyanopterus. Coregonus reighardi dymondi is a variant of C. zenithicus in northern bays of Lake Superior and Lake Nipigon. The morphological differences between members of spring and fall spawning populations of C. zenithicus in Lake Superior are no greater than those between geographically separate populations. We conclude that spawning time and geographic isolation act similarly in effecting differentiation of coregonine populations, and that populations with different spawning times do not necessarily represent different species.Key words: Coregonus zenithicus, cisco, Great Lakes, multivariate morphometrics, endangered species, taxonomy

Discrimination among spawning concentrations of Lake Superior lake herring based on trace element profiles in sagittae

USGS Publications Warehouse

Bronte, Charles R.; Hesselberg, Robert J.; Shoesmith, John A.; Hoff, Michael H.

1996-01-01

Little is known about the stock structure of lake herring Coregonus artedi in Lake Superior, and recent increases in harvestable stock sizes has led to expanded exploitation in some areas. Research on marine teleosts has demonstrated that chemical differences in sagittal otoliths can be used for identification of fish stocks. We used plasma emission spectrophotometry to measure the concentrations of 10 trace elements in the sagittal otoliths from lake herring captured at eight spawning sites in Lake Superior and from Little Star Lake, an inland lake outside the Lake Superior basin. Discriminant function analysis indicated that elemental concentrations provided site-specific information but that considerable overlap existed among some locations, especially those in western Lake Superior. Correct classification rates varied from 12.0% to 86.1% and were generally higher for spawning locations from embayments in eastern Lake Superior and for the outgroup population from Little Star Lake. The results presented here demonstrate the potential usefulness of this technique for strictly freshwater species, especially those that live in highly oligotrophic waters such as Lake Superior.

Coastal change-potential assessment of Sleeping Bear Dunes, Indiana Dunes, and Apostle Islands National Lakeshores to lake-level changes

USGS Publications Warehouse

Pendleton, Elizabeth A.; Thieler, E. Robert; Williams, S. Jeffress

2007-01-01

A change-potential index (CPI) was used to map the susceptibility of the shoreline to future lake-level change within Apostle Islands, Indiana Dunes, and Sleeping Bear Dunes National Lakeshores (NL) along Lake Superior and Lake Michigan. The CPI in the Great Lakes setting ranks the following in terms of their physical contribution to lake-level related coastal change: geomorphology, regional coastal slope, rate and direction (i.e., rise and fall) of relative lake-level change, historical shoreline change rates, annual ice cover and mean significant wave height. The rankings for each input variable were combined, and an index value calculated for 1-minute bins covering the parks. The CPI highlights those regions where the physical effects of lake-level and coastal change might be the greatest. This approach combines the coastal system's potential for change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the parks' natural susceptibility to the effects of lake-level variation. The CPI provides an objective technique for evaluation and long-term planning by scientists and park managers. The CPI is applied to the National Lakeshores of Apostle Islands, Indiana Dunes, and Sleeping Bear Dunes to test this methodology in lake settings. The National Lakeshores in this study consist of sand and gravel beaches, rock outcrops, and dune and glacial bluffs. The areas within these Great Lakes parks that are likely to experience the most lake-level-related coastal change are areas of unconsolidated sediment where regional coastal slope is low and wave energy is high.

Coastal/Great Lakes Forecasts by Zone

Science.gov Websites

Hazards Rip Currents Hypothermia Hurricanes Thunderstorms Lightning Coastal Flooding Tsunamis 406 EPIRB's Coastal/Great Lakes Forecasts by Zone >>Click on the area of interest below<< Coastal and

FISH-MEDIATED NUTRIENT AND ENERGY EXCHANGE BETWEEN A LAKE SUPERIOR COASTAL WETLAND AND ITS ADJACENT BAY

EPA Science Inventory

Little has been done to quantify fluxes of organisms, nutrients, and energy between freshwater coastal habitats and adjacent offshore waters or to evaluate the ecological implications of these exchanges on a whole-lake basis. To test the hypothesis that fish-mediated transport m...

Diet and prey selection by Lake Superior lake trout during springs 1986-2001

USGS Publications Warehouse

Ray, B.A.; Hrabik, T.R.; Ebener, M.P.; Gorman, O.T.; Schreiner, D.R.; Schram, S.T.; Sitar, S.P.; Mattes, W.P.; Bronte, C.R.

2007-01-01

We describe the diet and prey selectivity of lean (Salvelinus namaycush namaycush) and siscowet lake trout (S. n. siscowet) collected during spring (April–June) from Lake Superior during 1986–2001. We estimated prey selectivity by comparing prey numerical abundance estimates from spring bottom trawl surveys and lake trout diet information in similar areas from spring gill net surveys conducted annually in Lake Superior. Rainbow smelt (Osmerus mordax) was the most common prey and was positively selected by both lean and siscowet lake trout throughout the study. Selection by lean lake trout for coregonine (Coregonus spp.) prey increased after 1991 and corresponded with a slight decrease in selection for rainbow smelt. Siscowet positively selected for rainbow smelt after 1998, a change that was coincident with the decrease in selection for this prey item by lean lake trout. However, diet overlap between lean and siscowet lake trout was not strong and did not change significantly over the study period. Rainbow smelt remains an important prey species for lake trout in Lake Superior despite declines in abundance.

Analysis of the Lake Superior Watershed Seasonal Snow Cover

DTIC Science & Technology

2007-05-01

ER D C/ CR R EL T R -0 7 -5 Analysis of the Lake Superior Watershed Seasonal Snow Cover Steven F. Daly, Timothy B. Baldwin, and...unlimited. ERDC/CRREL TR-07-5 May 2007 Analysis of the Lake Superior Watershed Seasonal Snow Cover Steven F. Daly, Timothy B. Baldwin, and...12 5 GIS Analysis of SWE over the Lake Superior Watershed .........................................................15

Lake Superior, Duluth, MN

NASA Technical Reports Server (NTRS)

1973-01-01

This view shows the west end of Lake Superior and Duluth, MN (47.0N, 91.0W). Portions of Minnesota, Michigan and Ontario, Canada are in the scene. The Duluth metropolitan area is at the west end of the lake. The discoloration plume in the water at Duluth is the result of tailings from the iron ore smelters that process the iron ore from the nearby open pit mines seen near the upper left corner of the photo.

Bioaccumulation of toxaphene congeners in the lake superior food web

USGS Publications Warehouse

Muir, D.C.G.; Whittle, D.M.; De Vault, D. S.; Bronte, C.R.; Karlsson, H.; Backus, S.; Teixeira, C.

2004-01-01

The bioaccumulation and biotransformation of toxaphene was examined in the food webs of Lake Superior and Siskiwit Lake (Isle Royale) using congener specific analysis as well as stable isotope ratios of carbon and nitrogen to characterize food webs. Toxaphene concentrations (calculated using technical toxaphene) in lake trout (Salvelinus namaycush) from the western basin of Lake Superior (N = 95) averaged (±SD) 889 ± 896 ng/g wet wt and 60 ± 34 ng/g wet wt in Siskiwit Lake. Major congeners in lake trout were B8-789 (P38), B8-2226 (P44), B9-1679 (P50), and B9-1025 (P62). Toxaphene concentrations were found to vary seasonally, especially in lower food web organisms in Lake Superior and to a lesser extent in Siskiwit Lake. Toxaphene concentrations declined significantly in lake herring (Coregonus artedii), rainbow smelt (Omerus mordax), and slimy sculpin (Cottus cognatus) as well as in zooplankton (> 102 &mn;m) and Mysis (Mysis relicta) between May and October. The seasonal variation may reflect seasonal shifts in the species abundance within the zooplankton community. Trophic magnification factors (TMF) derived from regressions of toxaphene congener concentrations versus δ15N were > 1 for most octa- and nonachlorobornanes in Lake Superior except B8-1413 (P26) and B9-715. Log bioaccumulation factors (BAFs) for toxaphene congeners in lake trout (ng/g lipid/ng/L dissolved) ranged from 4.54 to 9.7 and were significantly correlated with log octanol-water partition coefficients. TMFs observed for total toxaphene and congener B9-1679 in Lake Superior were similar to those in Arctic lakes, as well as to previous studies in the Great Lakes, which suggests that the bioaccumulation behavior of toxaphene is similar in pelagic food webs of large, cold water systems. However, toxaphene concentrations were lower in lake trout from Siskiwit Lake and lakes in northwestern Ontario than in Lake Superior possibly because of shorter food chains and greater reliance on zooplankton or

Eutrophication monitoring for Lake Superior's Chequamegon ...

EPA Pesticide Factsheets

A priority for the Lake Superior CSMI was to identify susceptible nearshore eutrophication areas. We developed an integrated sampling design to collect baseline data for Lake Superior’s Chequamegon Bay to understand how nearshore physical processes and tributary loading relate to observed chlorophyll concentrations. Sampling included ship-based water samples combined with vertical CTD casts, continuous in situ towing and data collected from an autonomous underwater glider. Sampling was conducted during June, July and September. The glider collected regional data as part of three extended missions in Lake Superior over the same periods. During the study, two significant storm events impacted the western end of Lake Superior; the first occurred during July 11-12, with 8-10 inches of rain in 24hrs, and the second on July 21 with winds in excess of 161 km/h. Using GIS software, we organized these diverse temporal data sets along a continuous time line with temporally coincident Modis Satellite data to visualize surface sediment plumes in relation to water quality measurements. Preliminary results suggest that both events impacted regional water quality, and that nearshore physical forces (upwelling and currents) influenced the spatial variability. Results comparing in situ measures with remotely sensed images will be discussed. not applicable

Lake Superior, Deluth, MN

NASA Image and Video Library

1973-06-22

SL2-05-454 (22 June 1973) --- This view shows the west end of Lake Superior and Duluth, MN (47.0N, 91.0W). Portions of Minnesota, Michigan and Ontario, Canada are in the scene. The Duluth metropolitan area is at the west end of the lake. The discoloration plume in the water at Duluth is the result of tailings from the iron ore smelters that process the iron ore from the nearby open pit mines seen near the upper left corner of the photo. Photo credit: NASA

Classified Scrap in Lake Superior.

DTIC Science & Technology

1977-07-08

DEPARTMENT OF THE ARMY St. Paul District, Corps of Engineers Lake Superior Area Canal Park Duluth, Minnesota 55802 THE DAILY MINING GAZETTE...ago. Lind concurred with the reference groupts recommendations that Reserve Mining Company’s discharge of 67,000 tons of taconite tailings into Lake...installation located ap- proximately 13 miles north of Minneapolis - St. Paul, Minnesota . The prime contractor at the plant is Federal Cartridge Corporation with

Anatomy of the Midcontinent Rift beneath Lake Superior

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, M.D.; McGinnis, L.D.; Ervin, C.P.

1994-09-01

The structure and geometry of the 1.1-b.y.-old Midcontinent Rift system under Lake Superior is interpreted from 20 seismic reflection profiles recorded during the early and mid-1980s. The seismic data reveal that rift basins under Lake Superior are variable in depth and are partially filled with Keweenawan age sediments to depths of 7 km or more and volcanic flows to depths of 36 km. These rift basins form a continuous and sinuous feature that widens in the Allouez Basin and Marquette Basin in the western and central lake and narrows between White Ridge and the Porcupine Mountains. The rift basin bendsmore » southeast around the Keweenaw Peninsula, widens to about 100 km as it extends into the eastern half of Lake Superior, and exists the lake with its axis in the vicinity of Au Sable Point in Pictured Rocks National Lake Shore, about 50 km northeast of Munising, Michigan. The axis of the rift may exit the western end of the lake near Chequamegon Bay in Wisconsin. However, lack of data in that area limits interpretation at this time. Prior to late-stage reverse-faulting, a continuous basin of more uniform thickness was present beneath the lake. Crustal extension during rifting of approximately 50 km was followed by plate convergence and crustal shortening of approximately 30 km, with the major component of thrust from the southeast. Crustal shortening occurred after development of rift grabens and their filling with lava flows, but before deposition of the final sag basin sediments. Integration of information obtained from outcrops with data reported here indicates that the Lake Superior section of the rift is associated with as many as three major boundary faults.« less

Exploring trends, causes, and consequences of declining lipids in Lake Superior lake trout

EPA Science Inventory

The ability of lake trout to forage in deepwater habitats is facilitated by high lipid content, which affords buoyancy. In Lake Superior, lean lake trout historically occupied depths < 80 m, and siscowet lake trout occupied depths > 80 m. Siscowets have been known f...

77 FR 37321 - Safety Zone, Barrel Recovery, Lake Superior; Duluth, MN

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-21

... 1625-AA00 Safety Zone, Barrel Recovery, Lake Superior; Duluth, MN AGENCY: Coast Guard, DHS. ACTION... suspected to contain munitions waste materials which were dumped in the 1960's in a portion of Lake Superior... offshore in a portion of Lake Superior approximately 50 years ago. C. Discussion of the Final Rule The...

Evaluation of methods to estimate lake herring spawner abundance in Lake Superior

USGS Publications Warehouse

Yule, D.L.; Stockwell, J.D.; Cholwek, G.A.; Evrard, L.M.; Schram, S.; Seider, M.; Symbal, M.

2006-01-01

Historically, commercial fishers harvested Lake Superior lake herring Coregonus artedi for their flesh, but recently operators have targeted lake herring for roe. Because no surveys have estimated spawning female abundance, direct estimates of fishing mortality are lacking. The primary objective of this study was to determine the feasibility of using acoustic techniques in combination with midwater trawling to estimate spawning female lake herring densities in a Lake Superior statistical grid (i.e., a 10′ latitude × 10′ longitude area over which annual commercial harvest statistics are compiled). Midwater trawling showed that mature female lake herring were largely pelagic during the night in late November, accounting for 94.5% of all fish caught exceeding 250 mm total length. When calculating acoustic estimates of mature female lake herring, we excluded backscattering from smaller pelagic fishes like immature lake herring and rainbow smelt Osmerus mordax by applying an empirically derived threshold of −35.6 dB. We estimated the average density of mature females in statistical grid 1409 at 13.3 fish/ha and the total number of spawning females at 227,600 (95% confidence interval = 172,500–282,700). Using information on mature female densities, size structure, and fecundity, we estimate that females deposited 3.027 billion (109) eggs in grid 1409 (95% confidence interval = 2.356–3.778 billion). The relative estimation error of the mature female density estimate derived using a geostatistical model—based approach was low (12.3%), suggesting that the employed method was robust. Fishing mortality rates of all mature females and their eggs were estimated at 2.3% and 3.8%, respectively. The techniques described for enumerating spawning female lake herring could be used to develop a more accurate stock–recruitment model for Lake Superior lake herring.

CONTOURITES IN LAKE SUPERIOR

EPA Science Inventory

Contour currents influence sedimentation in an area 15 km wide and 65 km long at the base of the slope off the Keweenaw Peninsula in Lake Superior, northwestern Michigan. Seismic-reflection profiles (3.5 kHz) from this area show distinct wavy reflectors in a scoured trough at a d...

ARE COASTAL WETLAND-LAKE LINKAGES IMPORTANT?

EPA Science Inventory

Because coastal werlands typically comprise only a small percentage of the overall surface area in large lakes, an assumption has often been made that functional links between wetlands and the lake proper are of little significance. Recent investigations of functional linkages be...

Trophic connections in Lake Superior Part II: the nearshore fish community

USGS Publications Warehouse

Gamble, A.E.; Hrabik, T.R.; Yule, D.L.; Stockwell, J.D.

2011-01-01

We use detailed diet analyses of the predominant planktivorous, benthivorous and piscivorous fish species from Lake Superior to create a nearshore (bathymetric depths Mysis diluviana and Diporeia spp). Although the piscivorous fishes like lean lake trout (Salvelinus namaycush) fed to a lesser extent on Diporeia and Mysis, they were still strongly connected to these macroinvertebrates, which were consumed by their primary prey species (sculpin spp., rainbow smelt Osmerus mordax, and coregonines). The addition of Bythotrephes to summer/fall cisco and lake whitefish diets, and the decrease in rainbow smelt in lean lake trout diets (replaced by coregonines) were the largest observed differences relative to historic Lake Superior diet studies. Although the offshore food web of Lake Superior was simpler than nearshore in terms of number of fish species present, the two areas had remarkably similar food web structures, and both fish communities were primarily supported by Mysis and Diporeia. We conclude that declines in Mysis or Diporeia populations would have a significant impact on energy flow in Lake Superior. The food web information we generated can be used to better identify management strategies for Lake Superior.

Across Hydrological Interfaces from Coastal Watersheds to the Open Lake: Finding Landscape Signals in the Great Lakes Coastal Zone

EPA Science Inventory

Over the past decade, our group has been working to bring coastal ecosystems into integrated basin-lakewide monitoring and assessment strategies for the Great Lakes. We have conducted a wide range of research on coastal tributaries, coastal wetlands, semi-enclosed embayments an...

Agreement between Lake Superior State University and Lake Superior State University Faculty Association MEA-NEA. Effective Sept. 1, 1988 to August 31, 1991.

ERIC Educational Resources Information Center

Lake Superior State Univ., Sault Sainte Marie, MI.

The collective bargaining agreement between Lake Superior State University (Michigan) and the Lake Superior State University Faculty Association, an affiliate of the National Education Association, covering the period September 1, 1988 to August 31, 1991 is presented. The agreement covers the following items: definitions; recognition; association…

Genetic diversity of Diporeia in the Great Lakes: comparison of Lake Superior to the other Great Lakes

EPA Science Inventory

Abundances of Diporeia have dropped drastically in the Great Lakes, except in Lake Superior, where data suggest that population counts actually have risen. Various ecological, environmental, or geographic hypotheses have been proposed to explain the greater abundance of Lake Supe...

The spatial variability of coastal surface water temperature during upwelling. [in Lake Superior

NASA Technical Reports Server (NTRS)

Scarpace, F. L.; Green, T., III

1979-01-01

Thermal scanner imagery acquired during a field experiment designed to study an upwelling event in Lake Superior is investigated. Temperature data were measured by the thermal scanner, with a spatial resolution of 7 m. These data were correlated with temperatures measured from boats. One- and two-dimensional Fourier transforms of the data were calculated and temperature variances as a function of wavenumber were plotted. A k-to-the-minus-three dependence of the temperature variance on wavenumber was found in the wavenumber range of 1-25/km. At wavenumbers greater than 25/km, a k-to-the-minus-five-thirds dependence was found.

Winter diet of lake herring (Coregonus artedi) in western Lake Superior

USGS Publications Warehouse

Link, Jason; Selgeby, James H.; Hoff, Michael H.; Haskell, Craig

1995-01-01

Lake herring (Coregonus artedi) and zooplankton samples were simultaneously collected through the ice in the Apostle Islands region of western Lake Superior to provide information on the winter feeding ecology of lake herring. Zooplankton constituted the entire diet of the 38 lake herring collected for this study. We found no evidence of piscivory, although it has been reported by anglers. Diet selectivities were calculated using a Wilcoxon signed-ranks test and showed a preference of lake herring for larger zooplankton, especially Diaptomus sicilis, whereas the smaller copepod,Cyclops bicuspidatus thomasi, and immature copepod stages were selected against. These data document that overwintering copepods are food for a broad size range of lake herring in winter.

Fish community change in Lake Superior, 1970-2000

USGS Publications Warehouse

Bronte, Charles R.; Ebener, Mark P.; Schreiner, Donald R.; DeVault, David S.; Petzold, Michael M.; Jensen, Douglas A.; Richards, Carl; Lozano, Steven J.

2003-01-01

Changes in Lake Superior's fish community are reviewed from 1970 to 2000. Lake trout (Salvelinus namaycush) and lake whitefish (Coregonus clupeaformis) stocks have increased substantially and may be approaching ancestral states. Lake herring (Coregonus artedi) have also recovered, but under sporadic recruitment. Contaminant levels have declined and are in equilibrium with inputs, but toxaphene levels are higher than in all other Great Lakes. Sea lamprey (Petromyzon marinus) control, harvest limits, and stocking fostered recoveries of lake trout and allowed establishment of small nonnative salmonine populations. Natural reproduction supports most salmonine populations, therefore further stocking is not required. Nonnative salmonines will likely remain minor components of the fish community. Forage biomass has shifted from exotic rainbow smelt (Osmerus mordax) to native species, and high predation may prevent their recovery. Introductions of exotics have increased and threaten the recovering fish community. Agencies have little influence on the abundance of forage fish or the major predator, siscowet lake trout, and must now focus on habitat protection and enhancement in nearshore areas and prevent additional species introductions to further restoration. Persistence of Lake Superior's native deepwater species is in contrast to other Great Lakes where restoration will be difficult in the absence of these ecologically important fishes.

FORAGE FISH AND ZOOPLANKTON COMMUNITY COMPOSITION IN WESTERN LAKE SUPERIOR

EPA Science Inventory

We assessed the abundance, size, and species composition of the fish and zooplankton communities of western Lake Superior during 1996 and 1997. Data were analyzed for 3 ecoregions (Duluth-Superior (1), Apostle Islands (2), Minnesota coast (3) differing in lake bathymetry, phsiodo...

Optically stimulated luminescence dating of late Holocene raised strandplain sequences adjacent to Lakes Michigan and Superior, Upper Peninsula, Michigan, USA

USGS Publications Warehouse

Argyilan, Erin P.; Forman, Steven L.; Johnston, John W.; Wilcox, Douglas A.

2005-01-01

This study evaluates the accuracy of optically stimulated luminescence to date well-preserved strandline sequences at Manistique/Thompson bay (Lake Michigan), and Tahquamenon and Grand Traverse Bays (Lake Superior) that span the past ∼4500 yr. The single aliquot regeneration (SAR) method is applied to produce absolute ages for littoral and eolian sediments. SAR ages are compared against AMS and conventional 14C ages on swale organics. Modern littoral and eolian sediments yield SAR ages 14C ages on swale organics. Significant variability in 14C ages >2000 cal yr B.P. complicates comparison to SAR ages at all sites. However, a SAR age of 4280 ± 390 yr (UIC913) on ridge77 at Tahquamenon Bay is consistent with regional regression from the high lake level of the Nipissing II phase ca. 4500 cal yr B.P. SAR ages indicate a decrease in ridge formation rate after ∼1500 yr ago, likely reflecting separation of Lake Superior from lakes Huron and Michigan. This study shows that SAR is a credible alternative to 14C methods for dating littoral and eolian landforms in Great Lakes and other coastal strandplains where 14C methods prove problematic.

Coastal groundwater/surface-water interactions: a Great Lakes case study

USGS Publications Warehouse

Neff, Brian P.; Haack, Sheridan K.; Rosenberry, Donald O.; Savino, Jacqueline F.; Lundstrom, Scott C.

2006-01-01

Key similarities exist between marine and Great Lakes coastal environments. Water and nutrient fluxes across lakebeds in the Great Lakes are influenced by seiche and wind set-up and set-down, analogous to tidal influence in marine settings. Groundwater/surface-water interactions also commonly involve a saline-fresh water interface, although in the Great-Lakes cases, it is groundwater that is commonly saline and surface water that is fresh. Evapotranspiration also affects nearshore hydrology in both settings. Interactions between groundwater and surface water have recently been identified as an important component of ecological processes in the Great Lakes. Water withdrawals and the reversal of the groundwater/surface water seepage gradient are also common to many coastal areas around the Great Lakes. As compared to surface water, regional groundwater that discharges to western Lake Erie from Michigan is highly mineralized. Studies conducted by the U.S. Geological Survey at Erie State Game Area in southeastern Michigan, describe groundwater flow dynamics and chemistry, shallow lake-water chemistry, and fish and invertebrate communities. Results presented here provide an overview of recent progress of ongoing interdisciplinary studies of Great Lakes nearshore systems and describe a conceptual model that identifies relations among geologic, hydrologic, chemical, and biological processes in the coastal habitats of Lake Erie. This conceptual model is based on analysis of hydraulic head in piezometers at the study site and chemical analysis of deep and shallow coastal groundwater.

Fat content of the flesh of siscowets and lake trout from Lake Superior

USGS Publications Warehouse

Eschmeyer, Paul H.; Phillips, Arthur M.

1965-01-01

Samples of flesh were excised from the middorsal region of 67 siscowets (Salvelinus namaycush siscowet) and 46 lake trout (Salvelinus n. namaycush) collected from Lake Superior. Chemical analysis of the samples revealed a range in fat content (dry weight) of 32.5 to 88.8 per cent in siscowets and 6.6 to 52.3 per cent in lake trout. Percentage fat increased progressively with increase in length of fish in both forms, but the average rate of increase was far greater for siscowets than for lake trout at lengths between 12 and 20 inches. Despite substantial individual variation, the percentage fat in the two forms was widely different and without overlap at all comparable lengths. The range in iodine number of the fat was 100 to 160 for siscowets and 103 to 161 for lake trout; average values were generally lower for siscowets than for lake trout among fish of comparable length. Percentage fat and relative weight were not correlated significantly in either subspecies. The fat content of flesh samples from a distinctive subpopulation of Lake Superior lake trout known as 'humpers' was more closely similar to that of typical lean lake trout than to siscowets, but the rate of increase in fat with increasing length was greater than for lean lake trout. Flesh samples from hatchery-reared stocks of lake trout, hybrid lake trout X siscowets, and siscowets tended to support the view that the wide difference in fat content between siscowets and lake trout is genetically determined.

Prey selection by the Lake Superior fish community

USGS Publications Warehouse

Isaac, Edmund J.; Hrabik, Thomas R.; Stockwell, Jason D.; Gamble, Allison E.

2012-01-01

Mysis diluviana is an important prey item to the Lake Superior fish community as found through a recent diet study. We further evaluated this by relating the quantity of prey found in fish diets to the quantity of prey available to fish, providing insight into feeding behavior and prey preferences. We describe the seasonal prey selection of major fish species collected across 18 stations in Lake Superior in spring, summer, and fall of 2005. Of the major nearshore fish species, bloater (Coregonus hoyi), rainbow smelt (Osmerus mordax), and lake whitefish (Coregonus clupeaformis) consumed Mysis, and strongly selected Mysis over other prey items each season. However, lake whitefish also selected Bythotrephes in the fall when Bythotrephes were numerous. Cisco (Coregonus artedi), a major nearshore and offshore species, fed largely on calanoid copepods, and selected calanoid copepods (spring) and Bythotrephes (summer and fall). Cisco also targeted prey similarly across bathymetric depths. Other major offshore fish species such as kiyi (Coregonus kiyi) and deepwater sculpin (Myoxocephalus thompsoni) fed largely on Mysis, with kiyi targeting Mysis exclusively while deepwater sculpin did not prefer any single prey organism. The major offshore predator siscowet lake trout (Salvelinus namaycush siscowet) consumed deepwater sculpin and coregonines, but selected deepwater sculpin and Mysis each season, with juveniles having a higher selection for Mysis than adults. Our results suggest that Mysis is not only a commonly consumed prey item, but a highly preferred prey item for pelagic, benthic, and piscivorous fishes in nearshore and offshore waters of Lake Superior.

Early detection of invasive fishes in Lake Superior

EPA Science Inventory

Invasive species pose a serious threat to the Great Lakes warranting continual monitoring for the arrival of new species. Three locations in Lake Superior were identified as "high risk" for new introductions: St. Louis River near Duluth, MN, Upper St. Marys River near S...

Anthropogenic climate change has altered primary productivity in Lake Superior

PubMed Central

O'Beirne, M. D.; Werne, J. P.; Hecky, R. E.; Johnson, T. C.; Katsev, S.; Reavie, E. D.

2017-01-01

Anthropogenic climate change has the potential to alter many facets of Earth's freshwater resources, especially lacustrine ecosystems. The effects of anthropogenic changes in Lake Superior, which is Earth's largest freshwater lake by area, are not well documented (spatially or temporally) and predicted future states in response to climate change vary. Here we show that Lake Superior experienced a slow, steady increase in production throughout the Holocene using (paleo)productivity proxies in lacustrine sediments to reconstruct past changes in primary production. Furthermore, data from the last century indicate a rapid increase in primary production, which we attribute to increasing surface water temperatures and longer seasonal stratification related to longer ice-free periods in Lake Superior due to anthropogenic climate warming. These observations demonstrate that anthropogenic effects have become a prominent influence on one of Earth's largest, most pristine lacustrine ecosystems. PMID:28598413

Anthropogenic climate change has altered primary productivity in Lake Superior.

PubMed

O'Beirne, M D; Werne, J P; Hecky, R E; Johnson, T C; Katsev, S; Reavie, E D

2017-06-09

Anthropogenic climate change has the potential to alter many facets of Earth's freshwater resources, especially lacustrine ecosystems. The effects of anthropogenic changes in Lake Superior, which is Earth's largest freshwater lake by area, are not well documented (spatially or temporally) and predicted future states in response to climate change vary. Here we show that Lake Superior experienced a slow, steady increase in production throughout the Holocene using (paleo)productivity proxies in lacustrine sediments to reconstruct past changes in primary production. Furthermore, data from the last century indicate a rapid increase in primary production, which we attribute to increasing surface water temperatures and longer seasonal stratification related to longer ice-free periods in Lake Superior due to anthropogenic climate warming. These observations demonstrate that anthropogenic effects have become a prominent influence on one of Earth's largest, most pristine lacustrine ecosystems.

Movements of hatchery-reared lake trout in Lake Superior

USGS Publications Warehouse

Pycha, Richard L.; Dryer, William R.; King, George R.

1965-01-01

The history of stocking of lake trout (Salvelinus namaycush) in the Great Lakes is reviewed. The study of movements is based on capture of 24,275 fin-clipped lake trout taken in experimental gill nets and trawls and commercial gill nets. Yearling lake trout planted from shore dispersed to 15-fath (27-m) depths in 3A? hr. Most fish remained within 2 miles (3.2 km) of the planting site 2 months, but within 4 months some fish had moved as much as 17 miles (27 km). The highest abundance of planted lake trout was in areas 2-4 miles (3.2-6.4 km) from the planting site even 3 years after release. Distance moved and size of fish were not correlated. Dispersal of lake trout begins at planting and probably continues until the fish are mature. Most movement was eastward in southern Lake Superior and followed the counterclockwise surface currents. Movement is most rapid in areas of strong currents and slowest in areas of weak currents or eddies. Movement to areas west of the Keweenaw Peninsula was insignificant from plantings in Keweenaw Bay and nil from other plantings farther east. Lake trout planted in the eastern third of the lake dispersed more randomly than those planted farther west. Few fish moved farther offshore than the 50-fath (91-m) contour. Lake trout planted in Canadian waters made insignificant contributions to populations in US waters.

Observations of the Winter Thermal Structure of Lake Superior

NASA Astrophysics Data System (ADS)

Titze, Daniel James

Moored thermistor strings that span the water column have been deployed at up to seven locations throughout Lake Superior from 2005 through present, producing a unique year-round record of the thermal structure of a large lake. This extensive temperature record reveals significant interannual and spatial variability in Lake Superior's winter heat content, thermocline depth, and phenology. Of particular mention is a stark contrast in thermal structure between the cold, icy winter of 2009 and the much warmer winter of 2012, during which especially strong and weak negative stratification was observed, respectively. Significant interannual and spatial variability was also observed in Lake Superior ice cover, as shown through data extracted from Ice Mapping System satellite imagery (NOAA/NESDIS 2004). When water column heat content was estimated from temperature data and analyzed in concert with lake ice-cover data, it was found that ice cover can inhibit heat flux between the lake and the atmosphere, and that spatial variability in ice cover can translate into spatial variability in end-of-winter heat content. Such variability in end-of-winter heat content is found to be preserved through the spring warming season, and is strongly correlated with variability in the timing of the onset of summer stratification, with regions that have warmer end-of-winter water columns stratifying earlier than regions with colder end-of-winter water-columns.

Sea lamprey abundance and management in Lake Superior 1957-1999

USGS Publications Warehouse

Heinrich, John W.; Mullett, Katherine M.; Hansen, Michael J.; Adams, Jean V.; Klar, Gerald T.; Johnson, David A.; Christie, Gavin C.; Young, Robert J.

2003-01-01

The international sea lamprey (Petromyzon marinus) control program successfully laid the foundation for rehabilitation of lake trout (Salvelinus namaycush) in Lake Superior and was well coordinated among management agencies during 1957–1999. The lampricide TFM was the primary control tool, with recurring treatments in 52 larval-producing streams. Barriers and sterile-male-release, as alternative control technologies, were significant elements of the program. Barriers blocked spawning sea lampreys from substantial areas of habitat for sea lamprey larvae during 1966–1999, and the sterile-male-release technique was used to reduce larval production during 1991–1996. Sea lamprey control resulted in the suppression of sea lamprey populations in Lake Superior, as evidenced by the linear decline in spawner abundance during 1962–1999. However, sea lamprey abundance was not as low as the targets specified in the fish community objectives. Most of the parasitic sea lampreys in Lake Superior probably originated from survivors of lampricide treatments. Self-sustaining populations of lake trout were restored in most of the lake by 1996, although many were killed annually by sea lampreys. Economic injury levels for damage to fish populations by sea lampreys are being developed and will be used to distribute sea lamprey control resources among the Great Lakes.

Practitioners' views of science needs for the Great Lakes coastal ecosystem

USGS Publications Warehouse

Pebbles, Victoria; Lillard, Elizabath C.; Seelbach, Paul W.; Fogarty, Lisa Reynolds

2015-01-01

In 2014, the U.S. Geological Survey Great Lake Science Center (USGS-GLSC) and the USGS-Michigan Water Science Center partnered with the Great Lakes Commission (GLC) to conduct a series of four workshops with coastal practitioners and managers across the Great Lakes basin to highlight the need for, and get input on, a Great Lakes regional coastal science strategy. To this end, this report is intended to help guide USGS coastal and nearshore science priorities, but may also help guide other science agencies. The USGS-GLSC partnership on this effort was part of a broader five-year Memorandum of Understanding between the USGS-GLSC and the GLC to enhance communications between coastal science and management communities within the Great Lakes region. This report presents a summary and analysis of participant feedback from the four workshops held in 2014. Participant feedback included participant worksheets as well as interactive drawing sessions, individual notes and group flip chart notes from each workshop. The results are presented as a series of findings that can be used to guide USGS coastal/nearshore science priorities in support of management needs at local, state and regional scales.

LAKE HERRING (COREGONUS ARTEDI) AND RAINBOW SMELT (OSMERUS MORDAX) DIETS IN LAKE SUPERIOR

EPA Science Inventory

This manuscript reports on the diets of lake herring and rainbow smelt, currently the two dominant forage fish species (fish that are food for game fishes) in western Lake Superior. Despite the pelagic nature of both these species, they have substantially different diets and henc...

Status of the shortjaw cisco (Coregonus zenithicus) in Lake Superior

USGS Publications Warehouse

Hoff, Michael H.; Todd, Thomas N.

2004-01-01

The shortjaw cisco (Coregonus zenithicus) was historically found in Lakes Huron, Michigan, and Superior, but has been extirpated in Lakes Huron and Michigan apparently as the result of commercial overharvest. During 1999-2001, we conducted an assessment of shortjaw cisco abundance in five areas, spanning the U.S. waters of Lake Superior, and compared our results with the abundance measured at those areas in 1921-1922. The shortjaw cisco was found at four of the five areas sampled, but abundances were so low that they were not significantly different from zero. In the four areas where shortjaw ciscoes were found, abundance declined significantly by 99% from the 1920s to the present. To increase populations of this once economically and ecologically important species in Lake Superior, an interagency rehabilitation effort is needed. Population monitoring is recommended to assess population trends and to evaluate success of rehabilitation efforts.

A MANAGEMENT SUPPORT SYSTEM FOR GREAT LAKES COASTAL WETLANDS

EPA Science Inventory

The Great Lakes National Program Office in conjunction with the Great Lakes Commission and other researchers is leading a large scale collaborative effort that will yield, in unprecedented detail, a management support system for Great Lakes coastal wetlands. This entails the dev...

77 FR 35857 - Safety Zone, Fireworks Display, Lake Superior; Duluth, MN

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-15

... 1625-AA00 Safety Zone, Fireworks Display, Lake Superior; Duluth, MN AGENCY: Coast Guard, DHS. ACTION... of Lake Superior during the Duluth Fourth Fest fireworks display. This temporary safety zone is necessary to protect spectators and vessels from the hazards associated with fireworks displays. DATES: This...

Discrimination among spawning aggregations of lake herring from Lake Superior using whole-body morphometric characters

USGS Publications Warehouse

Hoff, Michael H.

2004-01-01

The lake herring (Coregonus artedi) was one of the most commercially and ecologically valuable Lake Superior fishes, but declined in the second half of the 20th century as the result of overharvest of putatively discrete stocks. No tools were previously available that described lake herring stock structure and accurately classified lake herring to their spawning stocks. The accuracy of discriminating among spawning aggregations was evaluated using whole-body morphometrics based on a truss network. Lake herring were collected from 11 spawning aggregations in Lake Superior and two inland Wisconsin lakes to evaluate morphometrics as a stock discrimination tool. Discriminant function analysis correctly classified 53% of all fish from all spawning aggregations, and fish from all but one aggregation were classified at greater rates than were possible by chance. Discriminant analysis also correctly classified 66% of fish to nearest neighbor groups, which were groups that accounted for the possibility of mixing among the aggregations. Stepwise discriminant analysis showed that posterior body length and depth measurements were among the best discriminators of spawning aggregations. These findings support other evidence that discrete stocks of lake herring exist in Lake Superior, and fishery managers should consider all but one of the spawning aggregations as discrete stocks. Abundance, annual harvest, total annual mortality rate, and exploitation data should be collected from each stock, and surplus production of each stock should be estimated. Prudent management of stock surplus production and exploitation rates will aid in restoration of stocks and will prevent a repeat of the stock collapses that occurred in the middle of the 20th century, when the species was nearly extirpated from the lake.

Delineation of sympatric morphotypes of lake trout in Lake Superior

USGS Publications Warehouse

Moore, Seth A.; Bronte, Charles R.

2001-01-01

Three morphotypes of lake trout Salvelinus namaycush are recognized in Lake Superior: lean, siscowet, and humper. Absolute morphotype assignment can be difficult. We used a size-free, whole-body morphometric analysis (truss protocol) to determine whether differences in body shape existed among lake trout morphotypes. Our results showed discrimination where traditional morphometric characters and meristic measurements failed to detect differences. Principal components analysis revealed some separation of all three morphotypes based on head and caudal peduncle shape, but it also indicated considerable overlap in score values. Humper lake trout have smaller caudal peduncle widths to head length and depth characters than do lean or siscowet lake trout. Lean lake trout had larger head measures to caudal widths, whereas siscowet had higher caudal peduncle to head measures. Backward stepwise discriminant function analysis retained two head measures, three midbody measures, and four caudal peduncle measures; correct classification rates when using these variables were 83% for leans, 80% for siscowets, and 83% for humpers, which suggests the measures we used for initial classification were consistent. Although clear ecological reasons for these differences are not readily apparent, patterns in misclassification rates may be consistent with evolutionary hypotheses for lake trout within the Laurentian Great Lakes.

New insight into defining the lakes of the southern Baltic coastal zone.

PubMed

Cieśliński, Roman; Olszewska, Alicja

2018-01-29

There exist many classification systems of hydrographic entities such as lakes found along the coastlines of seas and oceans. Each system has its advantages and can be used with some success in the area of protection and management. This paper aims to evaluate whether the studied lakes are only coastal lakes or rather bodies of water of a completely different hydrological and hydrochemical nature. The attempt to create a new classification system of Polish coastal lakes is related to the incompleteness of lake information in existing classifications. Thus far, the most frequently used are classifications based solely on lake basin morphogenesis or hydrochemical properties. The classifications in this paper are based not only on the magnitude of lake water salinity or hydrochemical analysis but also on isolation from the Baltic Sea and other sources of water. The key element of the new classification system for coastal bodies of water is a departure from the existing system used to classify lakes in Poland and the introduction of ion-"tracking" methods designed to identify anion and cation distributions in each body of water of interest. As a result of the work, a new classification of lakes of the southern Baltic Sea coastal zone was created. Featured objects such as permanently brackish lakes, brackish lakes that may turn into freshwater lakes from time to time, freshwater lakes that may turn into brackish lakes from time to time, freshwater lakes that experience low levels of salinity due to specific incidents, and permanently freshwater lakes. The authors have adopted 200 mg Cl -  dm -3 as a maximum value of lake water salinity. There are many conditions that determine the membership of a lake to a particular group, but the most important is the isolation lakes from the Baltic Sea. Changing a condition may change the classification of a lake.

Causes of declining survival of lake trout stocked in U.S. waters of Lake Superior in 1963-1986

USGS Publications Warehouse

Hansen, Michael J.; Ebener, Mark P.; Schorfhaar, Richard G.; Schram, Stephen T.; Schreiner, Donald R.; Selgeby, James H.; Taylor, William W.

1996-01-01

Survival of the 1963-1982 year-classes of stocked yearling lake trout Salvelinus namaycush declined significantly over time in Lake Superior. To investigate possible causes of this decline, a Ricker model of stock-recruitment was used to describe the catch per effort (CPE) of age-7 stocked lake trout in the Michigan, Minnesota, and Wisconsin waters of Lake Superior as functions of the numbers of yearlings stocked 6 years earlier (an index of density dependence), the density (CPE) of wild adult lake trout (an index of predation), and large-mesh (a?Y 114-mm stretch-measure) gill-net fishing effort (an index of fishing mortality). Declining CPE of stocked lake trout in Michigan and Wisconsin was significantly associated with increasing large-mesh gillnet fishing effort. Declining CPE of stocked lake trout in Minnesota was significantly associated with increasing density of wild lake trout. Declining survival of stocked lake trout may therefore have been caused by increased mortality in large-mesh gill-net fisheries in Michigan and Wisconsin, and by predation by wild lake trout that recently recolonized the Minnesota area. We recommend that experimental management be pursued to determine the relative importance of large-mesh gillnet fishing effort and of predation by wild lake trout on the survival of stocked lake trout in U.S. waters of Lake Superior.

Coastal Lake Record of Holocene Paleo-Storms from Northwest Florida

NASA Astrophysics Data System (ADS)

Donoghue, J. F.; Coor, J. L.; Wang, Y.; Das, O.; Kish, S.; Elsner, J.; Hu, X. B.; Niedoroda, A. W.; Ye, M.

2009-12-01

The northwest Florida coast of the Gulf of Mexico has an unusually active storm history. Climate records for a study area in the mid-region of the Florida panhandle coast show that 29 hurricanes have made landfall within a 100-km radius during historic time. These events included 9 major storms (category 3 or higher). A longer-term geologic record of major storm impacts is essential for better understanding storm climatology and refining morphodynamic models. The Florida panhandle region contains a series of unique coastal lakes which are long-lived and whose bottom sediments hold a long-term record of coastal storm occurrence. The lakes are normally isolated from the open Gulf, protected behind a near-continuous dune barrier. Lake water is normally fresh to brackish. Lake bottom sediments consist of organic-rich muds. During major storms the dunes are breached and the lakes are temporarily open to marine water and the possibility of sandy overwash. Both a sedimentologic and geochemical signature is imparted to the lake sediments by storm events. Bottom sediment cores have been collected from the lakes. The cores have been subsampled and subjected to sedimentologic, stable isotopic and geochronologic analyses. The result is a sediment history of the lakes, and a record of storm occurrence during the past few millennia. The outcome is a better understanding of the long-term risk of major storms. The findings are being incorporated into a larger model designed to make reliable predictions of the effects of near-future climate change on natural coastal systems and on coastal infrastructure, and to enable cost-effective mitigation and adaptation strategies.

Ups and Downs of Burbot and their predator Lake Trout in Lake Superior, 1953-2011

USGS Publications Warehouse

Gorman, Owen T.; Sitar, Shawn P.

2013-01-01

The fish community of Lake Superior has undergone a spectacular cycle of decline and recovery over the past 60 years. A combination of Sea Lamprey Petromyzon marinus depredation and commercial overfishing resulted in severe declines in Lake Trout Salvelinus namaycush, which served as the primary top predator of the community. Burbot Lota lota populations also declined as a result of Sea Lamprey depredation, largely owing to the loss of adult fish. After Sea Lamprey control measures were instituted in the early 1960s, Burbot populations rebounded rapidly but Lake Trout populations recovered more slowly and recovery was not fully evident until the mid-1980s. As Lake Trout populations recovered, Burbot populations began to decline, and predation on small Burbot was identified as the most likely cause. By 2000, Burbot densities had dropped below their nadir in the early 1960s and have continued to decline, with the densities of juveniles and small adults falling below that of large adults. Although Burbot populations are at record lows in Lake Superior, the density of large reproductive adults remains stable and a large reserve of adult Burbot is present in deep offshore waters. The combination of the Burbot's early maturation, long life span, and high fecundity provides the species with the resiliency to remain a viable member of the Lake Superior fish community into the foreseeable future.

Effects of lake trout refuges on lake whitefish and cisco in the Apostle Islands Region of Lake Superior

USGS Publications Warehouse

Zuccarino-Crowe , Chiara M.; Taylor, William W.; Hansen, Michael J.; Seider, Michael J.; Krueger, Charles C.

2016-01-01

Lake trout refuges in the Apostle Islands region of Lake Superior are analogous to the concept of marine protected areas. These refuges, established specifically for lake trout (Salvelinus namaycush) and closed to most forms of recreational and commercial fishing, were implicated as one of several management actions leading to successful rehabilitation of Lake Superior lake trout. To investigate the potential significance of Gull Island Shoal and Devils Island Shoal refuges for populations of not only lake trout but also other fish species, relative abundances of lake trout, lake whitefish (Coregonus clupeaformis), and cisco (Coregonus artedi) were compared between areas sampled inside versus outside of refuge boundaries. During 1982–2010, lake trout relative abundance was higher and increased faster inside the refuges, where lake trout fishing was prohibited, than outside the refuges. Over the same period, lake whitefish relative abundance increased faster inside than outside the refuges. Both evaluations provided clear evidence that refuges protected these species. In contrast, trends in relative abundance of cisco, a prey item of lake trout, did not differ significantly between areas inside and outside the refuges. This result did not suggest indirect or cascading refuge effects due to changes in predator levels. Overall, this study highlights the potential of species-specific refuges to benefit other fish species beyond those that were the refuges' original target. Improved understanding of refuge effects on multiple species of Great Lakes fishes can be valuable for developing rationales for refuge establishment and predicting associated fish community-level effects.

The pygmy whitefish, Coregonus coulteri, in Lake Superior

USGS Publications Warehouse

Eschmeyer, Paul H.; Bailey, Reeve M.

1955-01-01

Other cold-water fishes–cottids, ninespine sticklebacks, smelt, and four species of coregonines–were the most frequent associates of the pygmy whitefish. Lake trout and trout-perch were also taken with it at the same stations or in the same trawl hauls. Its closest relative in Lake Superior, the round whitefish, was not an ecological associate.

Early detection of non-indigenous fishes in Lake Superior

EPA Science Inventory

Invasive species pose a serious threat to the ecological stability of the Great Lakes warranting continual monitoring for the arrival of new species. Three locations in Lake Superior were identified as “high risk” for new introductions: St. Louis River near Duluth, M...

High levels of MHC class II allelic diversity in lake trout from Lake Superior

USGS Publications Warehouse

Dorschner, M.O.; Duris, T.; Bronte, C.R.; Burnham-Curtis, M. K.; Phillips, R.B.

2000-01-01

Sequence variation in a 216 bp portion of the major histocompatibility complex (MHC) II B1 domain was examined in 74 individual lake trout (Salvelinus namaycush) from different locations in Lake Superior. Forty-three alleles were obtained which encoded 71-72 amino acids of the mature protein. These sequences were compared with previous data obtained from five Pacific salmon species and Atlantic salmon using the same primers. Although all of the lake trout alleles clustered together in the neighbor-joining analysis of amino acid sequences, one amino acid allelic lineage was shared with Atlantic salmon (Salmo salar), a species in another genus which probably diverged from Salvelinus more than 10-20 million years ago. As shown previously in other salmonids, the level of nonsynonymous nucleotide substitution (d(N)) exceeded the level of synonymous substitution (d(S)). The level of nucleotide diversity at the MHC class II B1 locus was considerably higher in lake trout than in the Pacific salmon (genus Oncorhynchus). These results are consistent with the hypothesis that lake trout colonized Lake Superior from more than one refuge following the Wisconsin glaciation. Recent population bottlenecks may have reduced nucleotide diversity in Pacific salmon populations.

Coastal wetlands of Lake Superior’s south shore

EPA Science Inventory

There are more than two thousand coastal wetlands that encompass an area of about 215,000 ha in the Laurentian Great Lakes (LGL) of North America. Coastal wetlands in the LGL are distinguished hydrologically from nearby inland wetlands by a direct surface water connection with wa...

NEW RECORDS AND RANGE EXTENSIONS FOR SEVERAL CHIRONOMID GENERA IN LAKE SUPERIOR

EPA Science Inventory

Recent USEPA investigations of Lake Superior benthos in Minnesota, Wisconsin, and Michigan waters have resulted in the discovery of six uncommon genera of Chironomidae. Five new records of genera for Lake Superior and five significant Nearctic range extensions are reported. New r...

Denitrification Rates in a Lake Superior Coastal Wetland

EPA Science Inventory

In recent years, nitrogen has increased substantially in the Nation’s aquatic ecosystems mainly due to the increased use of fertilizers and land use practices. Denitrification is a process that can potentially mitigate this increased influx of fixed nitrate. Coastal wetlands are ...

BIOLOGICAL INDICATOR DEVELOPMENT AND CLASSIFICATION FOR GREAT LAKES COASTAL WETLANDS

EPA Science Inventory

Great Lakes coastal wetlands are a valued aquatic resource that provide important ecological functions for the Great Lakes including serving as fish habitat, aquatic food web support, and nutrient and sediment retention from watersheds. Great Lakes resource managers need assessme...

Lake trout (Salvelinus namaycush) populations in Lake Superior and their restoration in 1959-1993

USGS Publications Warehouse

Hansen, Michael J.; Peck, James W.; Schorfhaar, Richard G.; Selgeby, James H.; Schreiner, Donald R.; Schram, Stephen T.; Swanson, Bruce L.; MacCallum, Wayne R.; Burnham-Curtis, Mary K.; Curtis, Gary L.; Heinrich, John W.; Young, Robert J.

1995-01-01

Naturally-reproducing populations of lake trout (Salvelinus namaycush) have been reestablished in most of Lake Superior, but have not been restored to 1929-1943 average abundance. Progress toward lake trout restoration in Lake Superior is described, management actions are reviewed, and the effectiveness of those actions is evaluated; especially stocking lake trout as a tool for building spawning stocks, and subsequently, populations of wild recruits. Widespread destruction of lake trout stocks in the 1950s due to an intense fishery and sea lamprey (Petromyzon marinus) predation resulted in lower overall phenotypic diversity than was previously present. Stocking of yearling lake trout, begun in the 1950s, produced high densities of spawners that reproduced wherever inshore spawning habitat was widespread. Sea lampreys were greatly reduced, beginning in 1961, using selective chemical toxicants and barrier dams, but continue to exert substantial mortality. Fishery regulation was least effective in Wisconsin, where excessive gillnet effort caused high by-catch of lake trout until 1991, and in eastern Michigan, where lake trout restoration was deferred in favor of a tribal fishery for lake whitefish (Coregonus clupeaformis) in 1985. Restoration of stocks was quicker in offshore areas where remnant wild lake trout survived and fishing intensity was low, and was slower in inshore areas where stocked lake trout reproduced successfully and fishing intensity was high. Inshore stocks of wild lake trout are currently about 61 % of historic abundance in Michigan and 53% in Wisconsin. Direct comparison of modern and historic abundances of inshore lake trout stocks in Minnesota and Ontario is impossible due to lack of historic stock assessment data. Stocks in Minnesota are less abundant at present than in Michigan or Wisconsin, and stocks in Ontario are similar to those in Michigan. Further progress in stock recovery can only be achieved if sea lampreys are depressed and if

Coastal Changes, Eastern Lake Michigan, 1970-74.

DTIC Science & Technology

1981-01-01

an effective shore protection agent during the stormiest months of January, February, and March. Till and mixed till bluffs tended to erode less than...final report of a 4-year study of 17 profile lines located along the eastern shore of Lake Michigan. The work v-as carried out under the coastal...26 5 Sediment statistics sum~mary, eastern Lake Michigan (October 1973 to December 1974

Water quality of streams tributary to Lakes Superior and Michigan

USGS Publications Warehouse

Zimmerman, Jerome W.

1968-01-01

Water quality of streams tributary to Lakes Superior and Michigan was analyzed for 142 stations on 99 streams tributary to Lake Superior and 83 stations on 56 streams tributary to Lake Michigan during 1962-65. Concentrations of aluminum, copper, and iron were not affected greatly by flow or season. Magnesium, calcium, chlorides, total alkalinity, total hardness, and conductivity varied with the flow, temperature, and season; the lowest values were during the spring runoff and heavy rains, and the highest were during low water in late summer and the colder periods of winter. Concentrations of nitrate, silica, and sulfates were lowest in the spring and summer. Concentrations of tanninlike and ligninlike compounds were highest during the spring runoff and other high-water periods, and were lowest during freezeup when surface runoff was minimal. The pH values were highest from June to September and lowest during the spring runoff. Phenolphthalein alkalinity was detected primarily in the summer and coincided occasionally with low flows just before the spring thaw. Total hardness usually was lower in streams tributary to Lake Superior than in streams tributary to Lake Michigan. The total hardness was higher in the streams in Wisconsin than in the streams in Michigan along the west shore of Lake Michigan. It was lowest in the northernmost streams. The water quality of the streams in an area was related to the geological characteristics of the land.

Recoveries of tagged, hatchery-reared lake trout from Lake Superior

USGS Publications Warehouse

Buettner, Howard J.

1961-01-01

Plantings that totaled 13,384 tagged, hatchery-reared lake trout (Salvelinus namaycush)—18, 25, 30, or 37 months old—were made at four Lake Superior localities in 1955-57 to: measure possible increases of return from rearing to greater size and age; study the effect of season of planting on the rate of return; compare returns from different types of tags; and follow the movements of hatchery-reared fish. The great advantage of spring over fall planting, demonstrated for fingerling lake trout in earlier experiments, did not hold for fish planted at ages of 18 to 37 months. The improvement of recovery rates with increase of age over the same 18- to 37-month interval appears to be too small to justify the cost of rearing to the higher ages. The recovery rates were closely similar (3.9 to 4.8 percent) for lower-jaw tags and two types of nylon-streamer tags but were much lower than the rate for Petersen tags (12.4 percent). The pins of Petersen tags render the fish highly vulnerable to entanglement in the webbing of gill nets, the principal gear in Lake Superior. Recoveries of Petersen tags also came earlier after planting than did those of other tags. The time between planting and recovery and the distance traveled by the fish were clearly but not closely correlated. Mean distance between points of planting and recovery increased with time out, and average time out increased with the number of miles traveled. More than half of the recoveries of fish that had been at liberty over 2 years were made within 25 miles of the point of release.

Life history variation among four lake trout morphs at Isle Royale, Lake Superior

USGS Publications Warehouse

Hansen, Michael J.; Nate, Nancy A.; Muir, Andrew M.; Bronte, Charles R.; Zimmerman, Mara S.; Krueger, Charles C.

2016-01-01

Life history traits were compared among four morphs of lake trout at Isle Royale, Lake Superior. Of 738 lake trout caught at Isle Royale, 701 were assigned to a morph (119 humpers, 160 leans, 85 redfins, and 337 siscowets) using a combination of statistical analysis of head and body shape and visual assignment. On average, redfins were longer (544 mm), heavier (1,481 g), heavier at length (Wr = 94), more buoyant, and older (22 years) than siscowets (519 mm; 1,221 g; 90; 19 years), leans (479 mm; 854 g; 82; 13 years), and humpers (443 mm; 697 g; 87; 17 years). On average, leans grew from a younger age at length = 0 and shorter length at age = 0, at a faster early growth rate to a longer asymptotic length than the other three morphs, while redfins grew at a slower instantaneous rate and humpers grew to a shorter asymptotic length than other morphs. On average, leans were longer (562 mm) and older (15 years) at 50% maturity than redfins (427 mm, 12 years), siscowets (401 mm, 11 years), or humpers (394 mm, 13 years). Life history parameters did not differ between males and females within each morph. We conclude that differences in life history attributes of lean, humper, redfin, and siscowet morphs of lake trout are consistent with differential habitat use in waters around Isle Royale, Lake Superior.

Declining survival of lake trout stocked during 1963-1986 in U.S. waters of Lake Superior

USGS Publications Warehouse

Hansen, Michael J.; Ebener, Mark P.; Schorfhaar, Richard G.; Schram, Stephen T.; Schreiner, Donald R.; Selgeby, James H.

1994-01-01

The average catch per effort (CPE) values for the 1963–1982 year-classes of stocked lake trout Salvelinus namaycush caught at age 7 in gill nets and for the 1976–1986 year-classes caught at ages 2–4 in trawls declined significantly in U.S. waters of Lake Superior. The declines in CPE were not explained by reduced stocking, but rather by significant declines in survival indices of the year-classes of stocked lake trout. Increases in mortality occurred in year-classes before the fish reached ages 2–4, before they were recruited into the sport and commercial fisheries, and before they reached sizes vulnerable to sea lamprey predation. We conclude that declining abundance of stocked lake trout resulted from increased mortality, which may have been caused by competition, predation, or by a combination of these and other factors. Restoration of lake trout in Lake Superior may now depend on prudent management of naturally reproducing stocks rather than on stocking of hatchery-reared fish.

Benthic and Pelagic Contributions to Mysis Nutrition across Lake Superior

EPA Science Inventory

Quantification of the sources of nutrition to Mysis diluviana is needed to better understand the basis for production in Mysis lakes and to improve models of migration-driven nutrient and contaminant transport. We collected Mysis, plankton, and benthos across Lake Superior using ...

Systematically variable planktonic carbon metabolism along a land-to-lake gradient in a Great Lakes coastal zone.

PubMed

Weinke, Anthony D; Kendall, Scott T; Kroll, Daniel J; Strickler, Eric A; Weinert, Maggie E; Holcomb, Thomas M; Defore, Angela A; Dila, Deborah K; Snider, Michael J; Gereaux, Leon C; Biddanda, Bopaiah A

2014-11-01

During the summers of 2002-2013, we measured rates of carbon metabolism in surface waters of six sites across a land-to-lake gradient from the upstream end of drowned river-mouth Muskegon Lake (ML) (freshwater estuary) to 19 km offshore in Lake Michigan (LM) (a Great Lake). Despite considerable inter-year variability, the average rates of gross production (GP), respiration (R) and net production (NP) across ML (604 ± 58, 222 ± 22 and 381 ± 52 µg C L -1 day -1 , respectively) decreased steeply in the furthest offshore LM site (22 ± 3, 55 ± 17 and -33 ± 15 µg C L -1 day -1 , respectively). Along this land-to-lake gradient, GP decreased by 96 ± 1%, whereas R only decreased by 75 ± 9%, variably influencing the carbon balance along this coastal zone. All ML sites were consistently net autotrophic (mean GP:R = 2.7), while the furthest offshore LM site was net heterotrophic (mean GP:R = 0.4). Our study suggests that pelagic waters of this Great Lakes coastal estuary are net carbon sinks that transition into net carbon sources offshore. Reactive and dynamic estuarine coastal zones everywhere may contribute similarly to regional and global carbon cycles.

Characterization of Lake Michigan coastal lakes using zooplankton assemblages

USGS Publications Warehouse

Whitman, Richard L.; Nevers, Meredith B.; Goodrich, Maria L.; Murphy, Paul C.; Davis, Bruce M.

2004-01-01

Zooplankton assemblages and water quality were examined bi-weekly from 17 April to 19 October 1998 in 11 northeastern Lake Michigan coastal lakes of similar origin but varied in trophic status and limnological condition. All lakes were within or adjacent to Sleeping Bear Dunes National Lakeshore, Michigan. Zooplankton (principally microcrustaceans and rotifers) from triplicate Wisconsin net (80 I?m) vertical tows taken at each lake's deepest location were analyzed. Oxygen-temperature-pH-specific conductivity profiles and surface water quality were concurrently measured. Bray-Curtis similarity analysis showed small variations among sample replicates but large temporal differences. The potential use of zooplankton communities for environmental lake comparisons was evaluated by means of BIOENV (Primer 5.1) and principal component analyses. Zooplankton analyzed at the lowest identified taxonomic level yielded greatest sensitivity to limnological variation. Taxonomic and ecological aggregations of zooplankton data performed comparably, but less well than the finest taxonomic analysis. Secchi depth, chlorophyll a, and sulfate concentrations combined to give the best correlation with patterns of variation in the zooplankton data set. Principal component analysis of these variables revealed trophic status as the most influential major limnological gradient among the study lakes. Overall, zooplankton abundance was an excellent indicator of variation in trophic status.

The influence of ice on southern Lake Michigan coastal erosion

USGS Publications Warehouse

Barnes, P.W.; Kempema, E.W.; Reimnitz, E.; McCormick, M.

1994-01-01

Coastal ice does not protect the coast but enhances erosion by displacing severe winter wave energy from the beach to the shoreface and by entraining and transporting sediment alongshore and offshore. Three aspects of winter ice in Lake Michigan were studied over a 3-year period and found to have an important influence on coastal sediment dynamics and the coastal sediment budget: (1) the influence of coastal ice on shoreface morphology, (2) the transport of littoral sediments by ice, and (3) the formation of anchor and underwater ice as a frequent and important event entraining and transporting sediment. The nearshore ice complex contains a sediment load (0.2 - 1.2 t/m of coast) that is roughly equivalent to the average amount of sand eroded from the coastal bluffs and to the amount of sand ice- rafted offshore to the deep lake basin each year. -from Authors

Hydrogeomorphic and Anthropogenic Influences on Water Quality, Habitat, and Fish of Great Lakes Coastal Wetlands

EPA Science Inventory

Great Lakes coastal wetlands represent a dynamic interface between coastal watersheds and the open lake. Compared to the adjacent lakes, these wetlands have generally warmer water, reduced wave energy, shallow bathymetry, higher productivity, and structurally complex vegetated h...

Geomorphic and sedimentologic evidence for the separation of Lake Superior from Lake Michigan and Huron

USGS Publications Warehouse

Johnston, J.W.; Thompson, T.A.; Wilcox, D.A.; Baedke, S.J.

2007-01-01

A common break was recognized in four Lake Superior strandplain sequences using geomorphic and sedimentologic characteristics. Strandplains were divided into lakeward and landward sets of beach ridges using aerial photographs and topographic surveys to identify similar surficial features and core data to identify similar subsurface features. Cross-strandplain, elevation-trend changes from a lowering towards the lake in the landward set of beach ridges to a rise or reduction of slope towards the lake in the lakeward set of beach ridges indicates that the break is associated with an outlet change for Lake Superior. Correlation of this break between study sites and age model results for the strandplain sequences suggest that the outlet change occurred sometime after about 2,400 calendar years ago (after the Algoma phase). Age model results from one site (Grand Traverse Bay) suggest an alternate age closer to about 1,200 calendar years ago but age models need to be investigated further. The landward part of the strandplain was deposited when water levels were common in all three upper Great Lakes basins (Superior, Huron, and Michigan) and drained through the Port Huron/Sarnia outlet. The lakeward part was deposited after the Sault outlet started to help regulate water levels in the Lake Superior basin. The landward beach ridges are commonly better defined and continuous across the embayments, more numerous, larger in relief, wider, have greater vegetation density, and intervening swales contain more standing water and peat than the lakeward set. Changes in drainage patterns, foreshore sediment thickness and grain size help in identifying the break between sets in the strandplain sequences. Investigation of these breaks may help identify possible gaps in the record or missing ridges in strandplain sequences that may not be apparent when viewing age distributions and may justify the need for multiple age and glacial isostatic adjustment models. ?? 2006 Springer Science

ANTHROPOGENIC COPPER INVENTORIES AND MERCURY PROFILES FROM LAKE SUPERIOR: EVIDENCE FOR MINING IMPACTS

EPA Science Inventory

During the past 150 years, the mining indstry discharged more than a billion tons of tailings along Lake Superior shorelines and constructed numerous smelters in the watershed. Given the vast size of Lake Superior, were sediment profiles at locations far offshore impacted by near...

Otoliths reveal a diverse age structure for humper lake trout in Lake Superior

USGS Publications Warehouse

Burnham-Curtis, Mary K.; Bronte, Charles R.

1996-01-01

Humpers are one of at least three morphological variants of wild lake trout Salvelinus namaycush that maintain self-sustaining populations in Lake Superior. In an early study, bumpers from Isle Royale were shown to have a sharply truncated age distribution that was attributed to high mortality after age 11, but we suspected that these fish were underaged. In August of 1989 and 1992 we collected spawning humper lake trout from the same area and estimated their ages using both scales and sagittal otoliths. Humpers in our sample ranged from 5 to 13 years, based on scale annuli, but counts of sagitta annuli revealed ages of 8 to 28 years. Individual discrepancies between ages from scales and sagittae varied from –2 to 20 years, but differences between scale and otolith ages did not increase with individual age. We applied the von Bertalanffy growth model to the humper length-at-age data to indirectly assess the accuracy of aging estimates. The model significantly overestimated mean asymptotic length when scale ages were used, but the mean asymptotic length estimate was more similar to observed lengths when sagitta ages were used. Our results corroborate evidence that bumpers in Lake Superior grow more slowly and mature at a smaller size than lean lake trout; however, the age composition of bumpers is more diverse than previously thought. This particular population experiences little or no exploitation; the presence of older fish provides one standard by which the success of lake trout rehabilitation programs can be evaluated and emphasizes the need for accurate aging techniques.

Concentrations, Trends, and Air-Water Exchange of PAHs and PBDEs Derived from Passive Samplers in Lake Superior in 2011.

PubMed

Ruge, Zoe; Muir, Derek; Helm, Paul; Lohmann, Rainer

2015-12-01

Polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenylethers (PBDEs) are both currently released into the environment from anthropogenic activity. Both are hence primarily associated with populated or industrial areas, although wildfires can be an important source of PAHs, as well. Polyethylene passive samplers (PEs) were simultaneously deployed in surface water and near surface atmosphere to determine spatial trends and air-water gaseous exchange of 21 PAHs and 11 PBDEs at 19 sites across Lake Superior in 2011. Surface water and atmospheric PAH concentrations were greatest at urban sites (up to 65 ng L(-1) and 140 ng m(-3), respectively, averaged from June to October). Near populated regions, PAHs displayed net air-to-water deposition, but were near equilibrium off-shore. Retene, probably depositing following major wildfires in the region, dominated dissolved PAH concentrations at most Lake Superior sites. Atmospheric and dissolved PBDEs were greatest near urban and populated sites (up to 6.8 pg L(-1) and 15 pg m(-3), respectively, averaged from June to October), dominated by BDE-47. At most coastal sites, there was net gaseous deposition of BDE-47, with less brominated congeners contributing to Sault Ste. Marie and eastern open lake fluxes. Conversely, the central open lake and Eagle Harbor sites generally displayed volatilization of PBDEs into the atmosphere, mainly BDE-47.

Ecology of Lake Superior: Preface and Prospectus

EPA Science Inventory

This Special Issue of Aquatic Ecosystem Health and Management (AEHM) is the first of a two-volume set based on papers presented at a three-day International Conference in Duluth MN held in June 2010, and titled “Ecology of Lake Superior: Integrated Approaches and Challenges for t...

FACTORS INFLUENCING CARBON, NITROGEN, AND PHOSPHORUS CONTENT OF FISH FROM A LAKE SUPERIOR COASTAL WETLAND: LIFE HISTORY VERSUS MORPHOMETRICS.

EPA Science Inventory

The narrow fish nutrient ranges (C, 42.8-48.4%; N. 9.6-12.7%; P, 1.91-2.74%) in this study suggest that overall mean values are adequate for quantifying movement of C, N, or P as part of fish-mediated nutrient transport. We measured C, N, or P in 20 species of Lake Superior coas...

FACTORS INFLUENCING CARBON, NITROGEN, AND PHOSPHORUS CONTENT OF FISH FROM A LAKE SUPERIOR COASTAL WETLAND: LIFE HISTORY VERSUS MORPHOMETRICS

EPA Science Inventory

The narrow fish nutrient ranges (C, 42.8-48.4%; N, 9.6-12.7%; P, 1.91-2.74%) in this study suggest that overall mean values are adequate for quantifying movement of C, N, or P as part of fish-mediated nutrient transport. We measured C, N, and P in 20 species of Lake Superior coa...

A Holocene history of dune-mediated landscape change along the southeastern shore of Lake Superior

USGS Publications Warehouse

Loope, Walter L.; Fisher, Timothy G.; Jol, Harry M.; Anderton, John B.; Blewett, William L.

2004-01-01

Causal links that connect Holocene high stands of Lake Superior with dune building, stream damming and diversion and reservoir impoundment and infilling are inferred from a multidisciplinary investigation of a small watershed along the SE shore of Lake Superior. Radiocarbon ages of wood fragments from in-place stumps and soil O horizons, recovered from the bottom of 300-ha Grand Sable Lake, suggest that the near-shore inland lake was formed during multiple episodes of late Holocene dune damming of ancestral Sable Creek. Forest drownings at ~3000, 1530, and 300 cal. years BP are highly correlated with local soil burial events that occurred during high stands of Lake Superior. During these and earlier events, Sable Creek was diverted onto eastward-graded late Pleistocene meltwater terraces. Ground penetrating radar (GPR) reveals the early Holocene valley of Sable Creek (now filled) and its constituent sedimentary structures. Near-planar paleosols, identified with GPR, suggest two repeating modes of landscape evolution mediated by levels of Lake Superior. High lake stands drove stream damming, reservoir impoundment, and eolian infilling of impoundments. Falling Lake Superior levels brought decreased sand supply to dune dams and lowered stream base level. These latter factors promoted stream piracy, breaching of dune dams, and aerial exposure and forestation of infilled lakebeds. The bathymetry of Grand Sable Lake suggests that its shoreline configuration and depth varied in response to events of dune damming and subsequent dam breaching. The interrelated late Holocene events apparent in this study area suggest that variations in lake level have imposed complex hydrologic and geomorphic signatures on upper Great Lakes coasts.

Tracing Nitrogen through Landscapes to Coastal Wetlands using d15N of Larval Fish

EPA Science Inventory

Our objective was to evaluate the use of the nitrogen stable isotope value (d15N) of larval fish as an indicator of incipient anthropogenic nitrogen loading to coastal wetlands in the Great Lakes. We sampled coastal wetlands in five Lake Superior south shore tributaries that had ...

Progress in understanding the importance of coastal wetland nursery habitat to Great Lakes fisheries support

EPA Science Inventory

Great Lakes coastal wetlands provide important habitat for Great Lakes fishes of all life stages. A literature review of ichthyoplankton surveys conducted in Great Lakes coastal wetlands found at least 82 species reported to be captured during the larval stage. Twenty of those sp...

Expanding understanding of optical variability in Lake Superior with a 4-year dataset

NASA Astrophysics Data System (ADS)

Mouw, Colleen B.; Ciochetto, Audrey B.; Grunert, Brice; Yu, Angela

2017-07-01

Lake Superior is one of the largest freshwater lakes on our planet, but few optical observations have been made to allow for the development and validation of visible spectral satellite remote sensing products. The dataset described here focuses on coincidently observing inherent and apparent optical properties along with biogeochemical parameters. Specifically, we observe remote sensing reflectance, absorption, scattering, backscattering, attenuation, chlorophyll concentration, and suspended particulate matter over the ice-free months of 2013-2016. The dataset substantially increases the optical knowledge of the lake. In addition to visible spectral satellite algorithm development, the dataset is valuable for characterizing the variable light field, particle, phytoplankton, and colored dissolved organic matter distributions, and helpful in food web and carbon cycle investigations. The compiled data can be freely accessed at LakeSuperior/" target="_blank">https://seabass.gsfc.nasa.gov/archive/URI/Mouw/LakeSuperior/.

Evaluating the behavior of polychlorinated biphenyl compounds in Lake Superior using a dynamic multimedia model

NASA Astrophysics Data System (ADS)

Khan, T.; Perlinger, J. A.; Urban, N. R.

2017-12-01

Certain toxic, persistent, bioaccumulative, and semivolatile compounds known as atmosphere-surface exchangeable pollutants or ASEPs are emitted into the environment by primary sources, are transported, deposited to water surfaces, and can be later re-emitted causing the water to act as a secondary source. Polychlorinated biphenyl (PCB) compounds, a class of ASEPs, are of major concern in the Laurentian Great Lakes because of their historical use primarily as additives to oils and industrial fluids, and discharge from industrial sources. Following the ban on production in the U.S. in 1979, atmospheric concentrations of PCBs in the Lake Superior region decreased rapidly. Subsequently, PCB concentrations in the lake surface water also reached near equilibrium as the atmospheric levels of PCBs declined. However, previous studies on long-term PCB levels and trends in lake trout and walleye suggested that the initial rate of decline of PCB concentrations in fish has leveled off in Lake Superior. In this study, a dynamic multimedia flux model was developed with the objective to investigate the observed levelling off of PCB concentrations in Lake Superior fish. The model structure consists of two water layers (the epilimnion and the hypolimnion), and the surface mixed sediment layer, while atmospheric deposition is the primary external pathway of PCB inputs to the lake. The model was applied for different PCB congeners having a range of hydrophobicity and volatility. Using this model, we compare the long-term trends in predicted PCB concentrations in different environmental media with relevant available measurements for Lake Superior. We examine the seasonal depositional and exchange patterns, the relative importance of different process terms, and provide the most probable source of the current observed PCB levels in Lake Superior fish. In addition, we evaluate the role of current atmospheric PCB levels in sustaining the observed fish concentrations and appraise the need

Evaluating the growth potential of sea lampreys (Petromyzon marinus) feeding on siscowet lake trout (Salvelinus namaycush) in Lake Superior

USGS Publications Warehouse

Moody, E.K.; Weidel, B.C.; Ahrenstorff, T.D.; Mattes, W.P.; Kitchell, J.F.

2011-01-01

Differences in the preferred thermal habitat of Lake Superior lake trout morphotypes create alternative growth scenarios for parasitic sea lamprey (Petromyzon marinus) attached to lake trout hosts. Siscowet lake trout (Salvelinus namaycush) inhabit deep, consistently cold water (4–6 °C) and are more abundant than lean lake trout (Salvelinus namaycush) which occupy temperatures between 8 and 12 °C during summer thermal stratification. Using bioenergetics models we contrasted the growth potential of sea lampreys attached to siscowet and lean lake trout to determine how host temperature influences the growth and ultimate size of adult sea lamprey. Sea lampreys simulated under the thermal regime of siscowets are capable of reaching sizes within the range of adult sea lamprey sizes observed in Lake Superior tributaries. High lamprey wounding rates on siscowets suggest siscowets are important lamprey hosts. In addition, siscowets have higher survival rates from lamprey attacks than those observed for lean lake trout which raises the prospect that siscowets serve as a buffer to predation on more commercially desirable hosts such as lean lake trout, and could serve to subsidize lamprey growth.

RELEASE OF MERCURY FROM MINE RESIDUES INTO LAKE SUPERIOR

EPA Science Inventory

Using recent compilations of mine production and discharge rates, we will demonstrate that the cumulative Hg inputs to Lake Superior from mining activities are much higher than from atmosphereic deposition.

Spatial patterns in assemblage structures of pelagic forage fish and zooplankton in western Lake Superior

USGS Publications Warehouse

Johnson, Timothy B.; Hoff, Michael H.; Trebitz, Anett S.; Bronte, Charles R.; Corry, Timothy D.; Kitchell, James F.; Lozano, Stephen J.; Mason, Doran M.; Scharold, Jill V.; Schram, Stephen T.; Schreiner, Donald R.

2004-01-01

We assessed abundance, size, and species composition of forage fish and zooplankton communities of western Lake Superior during August 1996 and July 1997. Data were analyzed for three ecoregions (Duluth-Superior, Apostle Islands, and the open lake) differing in bathymetry and limnological and biological patterns. Zooplankton abundance was three times higher in the Duluth-Superior and Apostle Islands regions than in the open lake due to the large numbers of rotifers. Copepods were far more abundant than Cladocera in all ecoregions. Mean zooplankton size was larger in the open lake due to dominance by large calanoid copepods although size of individual taxa was similar among ecoregions. Forage fish abundance and biomass was highest in the Apostle Islands region and lowest in the open lake ecoregion. Lake herring (Coregonus artedi), rainbow smelt (Osmerus mordax) and deepwater ciscoes (Coregonus spp.) comprised over 90% of the abundance and biomass of fishes caught in midwater trawls and recorded with hydroacoustics. Growth and condition of fish was good, suggesting they were not resource limited. Fish and zooplankton assemblages differed among the three ecoregions of western Lake Superior, due to a combination of physical and limnological factors related to bathymetry and landscape position.

Hydrogeomorphic factors and ecosystem responses in coastal wetlands of the Great Lakes

USGS Publications Warehouse

Keough, Janet R.; Thompson, Todd A.; Guntenspergen, Glenn R.; Wilcox, Douglas A.

1999-01-01

Gauging the impact of manipulative activities, such as rehabilitation or management, on wetlands requires having a notion of the unmanipulated condition as a reference. And understanding of the reference condition requires knowledge of dominant factors influencing ecosystem processes and biological communities. In this paper, we focus on natural physical factors (conditions and processes) that drive coastal wetland ecosystems of the Laurentian Great Lakes. Great Lakes coastal wetlands develop under conditions of large-lake hydrology and disturbance imposed at a hiearchy of spatial and temporal scales and contain biotic communities adapted to unstable and unpredictable conditions. Coastal wetlands are configured along a continuum of hydrogeomorphic types: open coastal wetlands, drowned river mouth and flooded delta wetlands, and protected wetlands, each developing distinct ecosystem propertics and biotic communities. Hydrogeomorphic factors associated with the lake and watershed operate at a hierarchy of scales: a) local and short-term (seiches and ice action), b) watershed / lakewide / annual (seasonal water-level change), and c) larger or year-to-year and longer (regional and/or greater than one-year). Other physical factors include the unique water quality features of each lake. The aim of this paper is to provide scientists and managers with a framework for considering regional and site-specific geomorphometry and a hierarchy of physical processes in planning management and conservation projects.

Importance of coastal change variables in determining vulnerability to sea- and lake-level change

USGS Publications Warehouse

Pendleton, E.A.; Thieler, E.R.; Williams, S.J.

2010-01-01

In 2001, the U.S. Geological Survey began conducting scientific assessments of coastal vulnerability to potential future sea- and lake-level changes in 22 National Park Service sea- and lakeshore units. Coastal park units chosen for the assessment included a variety of geological and physical settings along the U.S. Atlantic, Pacific, Gulf of Mexico, Gulf of Alaska, Caribbean, and Great Lakes shorelines. This research is motivated by the need to understand and anticipate coastal changes caused by accelerating sea-level rise, as well as lake-level changes caused by climate change, over the next century. The goal of these assessments is to provide information that can be used to make long-term (decade to century) management decisions. Here we analyze the results of coastal vulnerability assessments for several coastal national park units. Index-based assessments quantify the likelihood that physical changes may occur based on analysis of the following variables: tidal range, ice cover, wave height, coastal slope, historical shoreline change rate, geomorphology, and historical rate of relative sea- or lake-level change. This approach seeks to combine a coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, and it provides a measure of the system's potential vulnerability to the effects of sea- or lake-level change. Assessments for 22 park units are combined to evaluate relationships among the variables used to derive the index. Results indicate that Atlantic and Gulf of Mexico parks have the highest vulnerability rankings relative to other park regions. A principal component analysis reveals that 99% of the index variability can be explained by four variables: geomorphology, regional coastal slope, water-level change rate, and mean significant wave height. Tidal range, ice cover, and historical shoreline change are not as important when the index is evaluated at large spatial scales (thousands of kilometers

Sanctuaries for lake trout in the Great Lakes

USGS Publications Warehouse

Stanley, Jon G.; Eshenroder, Randy L.; Hartman, Wilbur L.

1987-01-01

Populations of lake trout, severely depleted in Lake Superior and virtually extirpated from the other Great Lakes because of sea lamprey predation and intense fishing, are now maintained by annual plantings of hatchery-reared fish in Lakes Michigan, Huron, and Ontario and parts of Lake Superior. The extensive coastal areas of the Great Lakes and proximity to large populations resulted in fishing pressure on planted lake trout heavy enough to push annual mortality associated with sport and commercial fisheries well above the critical level needed to reestablish self-sustaining stocks. The interagency, international program for rehabilitating lake trout includes controlling sea lamprey abundance, stocking hatchery-reared lake trout, managing the catch, and establishing sanctuaries where harvest is prohibited. Three lake trout sanctuaries have been established in Lake Michigan: the Fox Island Sanctuary of 121, 500 ha, in the Chippewa-Ottawa Treaty fishing zone in the northern region of the lake; the Milwaukee Reef Sanctuary of 160, 000 ha in midlake, in boundary waters of Michigan and Wisconsin; and Julian's Reef Sanctuary of 6, 500 ha, in Illinois waters. In northern Lake Huron, Drummond Island Sanctuary of 55, 000 ha is two thirds in Indian treaty-ceded waters in Michigan and one third in Ontario waters of Canada. A second sanctuary, Six Fathom Bank-Yankee Reef Sanctuary, in central Lake Huron contains 168, 000 ha. Sanctuary status for the Canadian areas remains to be approved by the Provincial government. In Lake Superior, sanctuaries protect the spawning grounds of Gull Island Shoal (70, 000 ha) and Devils Island Shoal (44, 000 ha) in Wisconsin's Apostle Island area. These seven sanctuaries, established by the several States and agreed upon by the States, Indian tribes, the U.S. Department of the Interior, and the Province of Ontario, contribute toward solving an interjurisdictional fishery problem.

Development of a new Lake-wide Multiple Gear Survey to Assess Status and Trends of the Lake Superior Fish Community and Lower Trophic Levels

EPA Science Inventory

The U.S. Geological Survey Great Lakes Science Center has developed a plan to implement revision of its annual fish community survey of Lake Superior. The primary objective of the revision is improvement of the sampling design to be more representative of the Lake Superior fish c...

Allelic variability in species and stocks of Lake Superior ciscoes (Coregoninae)

USGS Publications Warehouse

Todd, Thomas N.

1981-01-01

Starch gel electrophoresis was used as a means of recognizing species and stocks in Lake Superior Coregonus. Allelic variability at isocitrate dehydrogenase and glycerol-3-phosphate dehydrogenase loci was recorded for samples of lake herring (Coregonus artedii), bloater (C. hoyi), kiyi (C. kiyi), and shortjaw cisco (C. zenithicus) from five Lake Superior localities. The observed frequencies of genotypes within each subsample did not differ significantly from those expected on the basis of random mating, and suggested that each subsample represented either a random sample from a larger randomly mating population or an independent and isolated subpopulation within which mating was random. Significant contingency X2 values for comparisons between both localities and species suggested that more than one randomly mating population occurred among the Lake Superior ciscoes, but did not reveal how many such populations there were. In contrast to the genetic results of this study, morphology seems to be a better descriptor of cisco stocks, and identification of cisco stocks and species will still have to be based on morphological criteria until more data are forthcoming. Where several species are sympatric, management should strive to preserve the least abundant. Failure to do so could result in the extinction or depletion of the rarer forms.

Visual Sensitivity of Deepwater Fishes in Lake Superior

PubMed Central

Harrington, Kelly A.; Hrabik, Thomas R.; Mensinger, Allen F.

2015-01-01

The predator-prey interactions in the offshore food web of Lake Superior have been well documented, but the sensory systems mediating these interactions remain unknown. The deepwater sculpin, (Myoxocephalus thompsoni), siscowet (Salvelinus namaycush siscowet), and kiyi (Coregonus kiyi) inhabit low light level environments. To investigate the potential role of vision in predator-prey interactions, electroretinography was used to determine visual sensitivity for each species. Spectral sensitivity curves revealed peak sensitivity at 525 nm for each species which closely corresponds to the prevalent downwelling light spectrum at depth. To determine if sufficient light was available to mediate predator-prey interactions, visual sensitivity was correlated with the intensity of downwelling light in Lake Superior to construct visual depth profiles for each species. Sufficient daytime irradiance exists for visual interactions to approximately 325 m for siscowet and kiyi and 355 m for the deepwater sculpin during summer months. Under full moon conditions, sufficient irradiance exists to elicit ERG response to light available at approximately 30 m for the siscowet and kiyi and 45 m for the deepwater sculpin. Visual interactions are therefore possible at the depths and times when these organisms overlap in the water column indicating that vision may play a far greater role at depth in deep freshwater lakes than had been previously documented. PMID:25646781

Food of salmonine predators in Lake Superior, 1981-87

USGS Publications Warehouse

Conner, David J.; Bronte, Charles R.; Selgeby, James H.; Collins, Hollie L.

1993-01-01

Diets of ten species of Lake Superior salmonines are described. Rainbow smelt (Osmerus mordax) were the primary prey during all seasons and years for inshore lake trout (Salvelinus namaycush), Pacific salmon (Oncorhynchus spp.), Atlantic salmon (Salmo salar), brown trout (S. trutta), brook trout (Salvelinus fontinalis), and splake (lake trout x brook trout hybrid). Coregonines were the second most-important prey for chinook salmon (O. tshawytscha), siscowet trout (S. namaycush siscowet), and splake. Invertebrates were important to rainbow trout (O. mykiss), coho salmon (O. kisutch), and pink salmon (O. gorbuscha), especially during the summer. Diets of lake trout from inshore and offshore locations differed markedly. Rainbow smelt were the primary food of inshore lake trout, and coregonines were the main food of offshore lake trout. Chinook salmon and inshore lake trout had the most similar diets because they ate similar proportions of rainbow smelt and coregonines. Salmonines generally ate more rainbow smelt and less coregonines in proportion to the abundance of these prey in the lake. If rainbow smelt populations collapse, the ability of salmonines to convert to a diet based on lake herring (Coregonus artedi) could be important to the stability of predator populations.

The spatial scale for cisco recruitment dynamics in Lake Superior during 1978-2007

USGS Publications Warehouse

Rook, Benjamin J.; Hansen, Michael J.; Gorman, Owen T.

2012-01-01

The cisco Coregonus artedi was once the most abundant fish species in the Great Lakes, but currently cisco populations are greatly reduced and management agencies are attempting to restore the species throughout the basin. To increase understanding of the spatial scale at which density‐independent and density‐dependent factors influence cisco recruitment dynamics in the Great Lakes, we used a Ricker stock–recruitment model to identify and quantify the appropriate spatial scale for modeling age‐1 cisco recruitment dynamics in Lake Superior. We found that the recruitment variation of ciscoes in Lake Superior was best described by a five‐parameter regional model with separate stock–recruitment relationships for the western, southern, eastern, and northern regions. The spatial scale for modeling was about 260 km (range = 230–290 km). We also found that the density‐independent recruitment rate and the rate of compensatory density dependence varied among regions at different rates. The density‐independent recruitment rate was constant among regions (3.6 age‐1 recruits/spawner), whereas the rate of compensatory density dependence varied 16‐fold among regions (range = −0.2 to −2.9/spawner). Finally, we found that peak recruitment and the spawning stock size that produced peak recruitment varied among regions. Both peak recruitment (0.5–7.1 age‐1 recruits/ha) and the spawning stock size that produced peak recruitment (0.3–5.3 spawners/ha) varied 16‐fold among regions. Our findings support the hypothesis that the factors driving cisco recruitment operate within four different regions of Lake Superior, suggest that large‐scale abiotic factors are more important than small‐scale biotic factors in influencing cisco recruitment, and suggest that fishery managers throughout Lake Superior and the entire Great Lakes basin should address cisco restoration and management efforts on a regional scale in each lake.

Spawning Cisco investigations in Canada waters of Lake Superior during 2007

USGS Publications Warehouse

Yule, Daniel L.; Evrard, Lori M.; Cholwek, Gary A.; Addison, Peter A.; Cullis, Ken I.

2008-01-01

Cisco Coregonus artedi form pre-spawning aggregations in Lake Superior during November with the bulk of spawning occurring during late November through early December (Dryer and Beil 1964). Eggs are broadcast into open water (Smith 1956) with fertilized eggs settling to the lakebed (Dryer and Beil 1964). Peak hatching occurs the following May (United States Geological Survey – Great Lakes Science Center, GLSC, unpublished data). Interannual variability in year class strength is high, but tends to be synchronous across different regions of Lake Superior (Bronte et al. 2003). November 2005 sampling of Thunder Bay showed 14 year-classes were present with the oldest fish being from the 1984 year-class (Yule et al. 2008). The ciscoes sampled were predominantly from five year classes that hatched during 1988, 1989, 1990, 1998, and 2003. These same strong year-classes were found in the western arm of Lake Superior during November 2006 (GLSC, unpublished data). Growth is rapid in the first few years of life with minimal growth after age-8 (Yule et al. 2008). Ciscoes exceeding 250 mm total length (TL) are typically sexually mature (Yule et al. 2006b, 2008). Thunder Bay ciscoes have high annual survival with rates for females and males averaging 0.80 and 0.75, respectively; females have higher rates of fishing-induced mortality compared to males but lower rates of natural mortality (Yule et al. 2008). Some Lake Superior stocks are currently commercially fished with the bulk of harvest occurring during November when fishers target females for their roe. The bulk of fish are harvested from Thunder Bay using suspended gillnets with mesh sizes ranging from 79-89 mm stretch measure. Ciscoes younger then age-5 make up a very small proportion (<0.1%) of the harvest (Yule, et al. 2008).

Hydroacoustic estimates of abundance and spatial distribution of pelagic prey fishes in western Lake Superior

USGS Publications Warehouse

Mason, Doran M.; Johnson, Timothy B.; Harvey, Chris J.; Kitchell, James F.; Schram, Stephen T.; Bronte, Charles R.; Hoff, Michael H.; Lozano, Stephen J.; Trebitz, Anett S.; Schreiner, Donald R.; Lamon, E. Conrad; Hrabik, Thomas R.

2005-01-01

Lake herring (Coregonus artedi) and rainbow smelt (Osmerus mordax) are a valuable prey resource for the recovering lake trout (Salvelinus namaycush) in Lake Superior. However, prey biomass may be insufficient to support the current predator demand. In August 1997, we assessed the abundance and spatial distribution of pelagic coregonines and rainbow smelt in western Lake Superior by combining a 120 kHz split beam acoustics system with midwater trawls. Coregonines comprised the majority of the midwater trawl catches and the length distributions for trawl caught fish coincided with estimated sizes of acoustic targets. Overall mean pelagic prey fish biomass was 15.56 kg ha−1 with the greatest fish biomass occurring in the Apostle Islands region (27.98 kg ha−1), followed by the Duluth Minnesota region (20.22 kg ha−1), and with the lowest biomass occurring in the open waters of western Lake Superior (9.46 kg ha−1). Biomass estimates from hydroacoustics were typically 2–134 times greater than estimates derived from spring bottom trawl surveys. Prey fish biomass for Lake Superior is about order of magnitude less than acoustic estimates for Lakes Michigan and Ontario. Discrepancies observed between bioenergetics-based estimates of predator consumption of coregonines and earlier coregonine biomass estimates may be accounted for by our hydroacoustic estimates.

Biotic and abiotic factors related to lake herring recruitment in the Wisconsin waters of Lake Superior, 1984-1998

USGS Publications Warehouse

Hoff, Michael H.

2004-01-01

Lake Superior lake herring (Coregonus artedi) recruitment to 13-14 months of age in the Wisconsin waters of Lake Superior varied by a factor of 5,233 during 1984-1998. Management agencies have sought models that accurately predict recruitment, but no satisfactory model had previously been developed. Lake herring recruitment was modeled to determine which factors most explained recruitment variability. The Ricker stock-recruitment model derived from only the paired stock and recruit data explained 35% of the variability in the recruitment data. The functional relationship that explained the greatest amount of recruitment variation (93%) included lake herring stock size, lake trout (Salvelinus namaycush) population size, slimy sculpin (Cottus cognatus) biomass, the interaction of mean daily wind speed in April (month of hatch) and lake herring stock size, and mean air temperature in April (when lake herring are 12-months old). Model results were interpreted to mean that lake herring recruitment was affected negatively by: slimy sculpin predation on lake herring ova; predation on age-0 lake herring by lake trout; and adult cannibalism on lake herring larvae, which was reduced by increased wind speed. April temperature was the variable that explained the least amount of variability in recruitment, but lake herring recruitment was positively affected by a warm April, which shortened winter and apparently reduced first-winter mortality. Stock size caused compensatory, density-dependent mortality on lake herring recruits. Management efforts appear best targeted at stock size protection, and empirical data implies that stock size in the Wisconsin waters of the lake should be maintained at 2.1-15.0 adults/ha in spring, bottom-trawl surveys.

MERCURY IN METAL ORE DEPOSITS: AN UNRECOGNIZED, WIDESPREAD SOURCE TO LAKE SUPERIOR SEDIMENTS, CONTRIBUTION #1072

EPA Science Inventory

Mining operations have worked the rich mineral resources of the Lake Superior Basin for over 150 years, leaving industrially impacted regions with tailing piles and smelters. In Lake Superior sediments, mercury and copper inventories increase towards shorelines and are highly cor...

Fringe benefit: Value of restoring coastal wetlands for Great Lakes fisheries

EPA Science Inventory

Fishery support is recognized as a valuable ecosystem service provided by Great Lakes coastal wetlands, but it is challenging to quantify because multiple species and habitats are involved. Recent studies indicate that coastal wetland area is proportional to fishery harvest among...

Factors affecting the evolution of coastal wetlands of the Laurentian Great Lakes: An overview

USGS Publications Warehouse

Mayer, T.; Edsall, T.; Munawar, M.

2004-01-01

Coastal wetlands play a pivotal role in the Great Lakes ecosystem. As buffer zones between the land and open waters of the Great Lakes, they perform a variety of essential functions providing both direct and indirect anthropogenic benefits. Geology, morphology and climate are the dominant variables that influence Laurentian Great Lakes wetland development. However, anthropogenic factors are the major contributors to alteration of natural wetland processes. This paper provides an overview of natural and anthropogenic factors important in Great Lakes coastal wetland development and provides statistical information describing the Great Lakes Basin. A brief description of wetlands classification and research issues is also presented.

Effectiveness of a refuge for Lake Trout in Western Lake Superior II: Simulation of future performance

USGS Publications Warehouse

Akins, Andrea L; Hansen, Michael J.; Seider, Michael J.

2015-01-01

Historically, Lake Superior supported one of the largest and most diverse Lake Trout Salvelinus namaycush fisheries in the Laurentian Great Lakes, but Lake Trout stocks collapsed due to excessive fishery exploitation and predation by Sea Lampreys Petromyzon marinus. Lake Trout stocking, Sea Lamprey control, and fishery regulations, including a refuge encompassing Gull Island Shoal (Apostle Islands region), were used to enable recovery of Lake Trout stocks that used this historically important spawning shoal. Our objective was to determine whether future sustainability of Lake Trout stocks will depend on the presence of the Gull Island Shoal Refuge. We constructed a stochastic age-structured simulation model to assess the effect of maintaining the refuge as a harvest management tool versus removing the refuge. In general, median abundances of age-4, age-4 and older (age-4+), and age-8+ fish collapsed at lower instantaneous fishing mortality rates (F) when the refuge was removed than when the refuge was maintained. With the refuge in place, the F that resulted in collapse depended on the rate of movement into and out of the refuge. Too many fish stayed in the refuge when movement was low (0–2%), and too many fish became vulnerable to fishing when movement was high (≥22%); thus, the refuge was more effective at intermediate rates of movement (10–11%). With the refuge in place, extinction did not occur at any simulated level of F, whereas refuge removal led to extinction at all combinations of commercial F and recreational F. Our results indicate that the Lake Trout population would be sustained by the refuge at all simulated F-values, whereas removal of the refuge would risk population collapse at much lower F (0.700–0.744). Therefore, the Gull Island Shoal Refuge is needed to sustain the Lake Trout population in eastern Wisconsin waters of Lake Superior.

Changing climate in the Lake Superior region: a case study of the June 2012 flood and its effects on the western-lake water column

NASA Astrophysics Data System (ADS)

Minor, E. C.; Forsman, B.; Guildford, S. J.

2013-12-01

In Lake Superior, the world's largest freshwater lake by area, we are seeing annual surface-water temperature increases outpacing those of the overlying atmosphere. We are also seeing ever earlier onsets of water-column stratification (in data sets from the mid-1980s to the present). In Minnesota, including the Lake Superior watershed, precipitation patterns are also shifting toward fewer and more extreme storm events, such as the June 2012 solstice flood, which impacted the western Lake Superior basin. We are interested in how such climatological changes will affect nutrient and carbon biogeochemistry in Lake Superior. The lake is currently an oligotrophic system exhibiting light limitation of primary production in winter and spring, with summer primary production generally limited by phosphorus and sometimes co-limited by iron. Analyses in the western arm of Lake Superior showed that the June 2012 flood brought large amounts of sediment and colored dissolved organic matter (CDOM) from the watershed into the lake. There was initially a ~50-fold spike in the total phosphorus concentrations (and a 5 fold spike in soluble reactive phosphorus) in flood-impacted waters. This disappeared rapidly, in large part due to sediment settling and did not lead to an increase in chlorophyll concentrations at monitored sampling sites. Instead, lake phytoplankton appeared light limited by a surface lens of warm water enriched in CDOM that persisted for over a month after the flood event itself. Our observations highlight the need for continuing research on these complex in-lake processes in order to make accurate predictions about longer term impacts of these large episodic inputs in CDOM, sediment, and nutrient loading.

Watershed and Lake Influences on the Energetic Base of Coastal Wetland Food Webs across the Great Lakes Basin

EPA Science Inventory

This manuscript examines the responses of Great Lakes coastal wetland food webs to nutrient enrichment and identifies three classes of systems whose food webs respond differently. Or is that differentially? Anyway, coastal wetlands with relatively long hydraulic residence times ...

Stable isotope ratios in swale sequences of Lake Superior as indicators of climate and lake level fluctuations during the Late Holocene

USGS Publications Warehouse

Sharma, Shruti; Mora, G.; Johnston, J.W.; Thompson, T.A.

2005-01-01

Beach ridges along the coastline of Lake Superior provide a long-term and detailed record of lake level fluctuations for the past 4000 cal BP. Although climate change has been invoked to explain these fluctuations, its role is still in debate. Here, we reconstruct water balance by employing peat samples collected from swale deposits present between beach ridge sequences at two locations along the coastline of Lake Superior. Carbon isotope ratios for Sphagnum remains from these peat deposits are used as a proxy for water balance because the presence or absence of water films on Sphagnum controls the overall isotope discrimination effects. Consequently, increased average water content in Sphagnum produces elevated ??13C values. Two maxima of Sphagnum ??13C values interpreted to reflect wetter conditions prevailed from 3400 to 2400 cal BP and from about 1900 to 1400 cal BP. There are two relatively short drier periods as inferred from low Sphagnum ??13C values: one is centered at about 2300 cal BP, and one begins at 1400 cal BP. A good covariance was found between Sphagnum ??13C values and reconstructed lake-levels for Lake Michigan in which elevated carbon isotope values correlate well with higher lake levels. Based on this covariance, we conclude that climate exerts a strong influence on lake levels in Lake Superior for the past 4000 cal BP. ?? 2005 Elsevier Ltd. All rights reserved.

Anthropogenic climate change has driven Lake Superior productivity beyond the range of Holocene variability

NASA Astrophysics Data System (ADS)

OBeirne, M. D.; Werne, J. P.; Hecky, R. E.; Johnson, T. C.; Katsev, S.; Reavie, E. D.

2013-12-01

Recent studies have noted that changes in Lake Superior's physical, chemical and biological processes are apparent - including a warming of the surface waters at a rate twice as great as the surrounding airshed in the last 20 years. These changes are often difficult to perceive as cause for concern when not placed within a historical context. In this study, bulk C and N abundance and stable isotope composition was determined on sediments from three piston and corresponding gravity cores, representing a record of lake-wide paleoproductivity trends spanning the Holocene. These data are compared with the same measurements on eight multi-cores sampled at high resolution spanning the past ~200 years, which allows for the historical comparison with recent (1800 A.D. to present) productivity trends. Throughout the Holocene, Lake Superior experienced a slow, steady increase in productivity consistent with conventional lake ontogeny. During the last 200 years, however, the Lake Superior basin has undergone biogeochemical changes that are unique in the context of the Holocene. Lake-wide sedimentary bulk organic carbon data indicate increasing primary production between 1900 and present, as indicated by a ~2‰ increase in δ13Corg. In contrast,δ15Norg values, which increased throughout the Holocene, become progressively 15N-depleted after 1900, likely due to atmospheric deposition of NOx from fossil fuel combustion. The most recent increases in primary productivity are likely a response to increasing water temperatures, leading to longer ice-free periods as previously documented in Lake Superior.

Spatial and temporal distribution of singlet oxygen in Lake Superior.

PubMed

Peterson, Britt M; McNally, Ann M; Cory, Rose M; Thoemke, John D; Cotner, James B; McNeill, Kristopher

2012-07-03

A multiyear field study was undertaken on Lake Superior to investigate singlet oxygen ((1)O(2)) photoproduction. Specifically, trends within the lake were examined, along with an assessment of whether correlations existed between chromophoric dissolved organic matter (CDOM) characteristics and (1)O(2) production rates and quantum yields. Quantum yield values were determined and used to estimate noontime surface (1)O(2) steady-state concentrations ([(1)O(2)](ss)). Samples were subdivided into three categories based on their absorbance properties (a300): riverine, river-impacted, or open lake sites. Using calculated surface [(1)O(2)](ss), photochemical half-lives under continuous summer sunlight were calculated for cimetidine, a pharmaceutical whose reaction with (1)O(2) has been established, to be on the order of hours, days, and a week for the riverine, river-impacted, and open lake waters, respectively. Of the CDOM properties investigated, it was found that dissolved organic carbon (DOC) and a300 were the best parameters for predicting production rates of [(1)O(2)](ss). For example, given the correlations found, one could predict [(1)O(2)](ss) within a factor of 4 using a300 alone. Changes in the quantum efficiency of (1)O(2) production upon dilution of river water samples with lake water samples demonstrated that the CDOM found in the open lake is not simply diluted riverine organic matter. The open lake pool was characterized by low absorption coefficient, low fluorescence, and low DOC, but more highly efficient (1)O(2) production and predominates the Lake Superior system spatially. This study establishes that parameters that reflect the quantity of CDOM (e.g., a300 and DOC) correlate with (1)O(2) production rates, while parameters that characterize the absorbance spectrum (e.g., spectral slope coefficient and E2:E3) correlate with (1)O(2) production quantum yields.

Evaluating Lake Superior nearshore offshore gradients using autonomous gliders

EPA Science Inventory

Slocum electric gliders are autonomous vehicles capable of continuously mapping subsurface conditions at high resolution for months at a time. During the 2016 CSMI in Lake Superior, seven glider deployments were undertaken through a partnership between University of Minnesota Dul...

Depth-specific Analyses of the Lake Superior Food Web

EPA Science Inventory

Characteristics of large, deep aquatic systems include depth gradients in community composition, in the quality and distribution of food resources, and in the strategies that organisms use to obtain their nutrition. In Lake Superior, nearshore communities that rely upon a combina...

Physiological modifications by seston in response to physicochemical gradients within Lake Superior

EPA Science Inventory

Lake Superior is a non-steady state and phosphorus (P) depleted ecosystem. In September 2011, the vertical distribution and composition of dissolved and particulate P-pools throughout the Lake were examined. Differences in seston P content were evident with depth, as average sest...

Density-independent survival of wild lake trout in the Apostle Islands area of Lake Superior

USGS Publications Warehouse

Bronte, Charles R.; Schram, Stephen T.; Selgeby, James H.; Swanson, Bruce L.

1995-01-01

The lake trout (Salvelinus namaycush) stock at Gull Island Shoal in western Lake Superior was one of only a few stocks of lean lake trout in the Great Lakes that survived overfishing and predation by the sea lamprey (Petromyzon marinus). Since the mid 1960s, the abundance of wild recruits measured at age 0 and the number of age-7 to -11 wild fish recruited to the fishable stock have increased. We used the Varley-Gradwell method to test for density-dependent survival between these life stages. Survival from age-0 to ages 7–11 was not affected by increasing density, which suggests that further increases in recruitment and stock size are still possible. We suggest that testing for the existence of density-dependent survival can be used to indicate when lake trout populations are rehabilitated.

Age, growth, and size of Lake Superior Pygmy Whitefish (Prosopium coulterii)

USGS Publications Warehouse

Stewart, Taylor; Derek Ogle,; Gorman, Owen T.; Vinson, Mark

2016-01-01

Pygmy Whitefish (Prosopium coulterii) are a small, glacial relict species with a disjunct distribution in North America and Siberia. In 2013 we collected Pygmy Whitefish at 28 stations from throughout Lake Superior. Total length was recorded for all fish and weight and sex were recorded and scales and otoliths were collected from a subsample. We compared the precision of estimated ages between readers and between scales and otoliths, estimated von Bertalanffy growth parameters for male and female Pygmy Whitefish, and reported the first weight-length relationship for Pygmy Whitefish. Age estimates between scales and otoliths differed significantly with otolith ages significantly greater for most ages after age-3. Maximum otolith age was nine for females and seven for males, which is older than previously reported for Pygmy Whitefish from Lake Superior. Growth was initially fast but slowed considerably after age-3 for males and age-4 for females, falling to 3–4 mm per year at maximum estimated ages. Females were longer than males after age-3. Our results suggest the size, age, and growth of Pygmy Whitefish in Lake Superior have not changed appreciably since 1953.

Historic and modern abundance of wild lean lake trout in Michigan waters of Lake Superior: Implications for restoration goals

USGS Publications Warehouse

Wilberg, Michael J.; Hansen, Michael J.; Bronte, Charles R.

2003-01-01

Populations of lake trout Salvelinus namaycush in Lake Superior collapsed in the late 1950s due to overfishing and predation by sea lampreys Petromyzon marinus. A binational effort to restore the lean morphotype of lake trout began with the stocking of hatchery-reared fish followed by the chemical control of sea lampreys and closure of the commercial fishery. Previous comparisons of the contemporary abundance of wild lean lake trout with that from historic commercial fishery statistics indicate that abundance was higher historically. However, this conclusion may be biased because several factors—the inclusion of siscowet (the “fat” morphotype of lake trout) in the catch statistics, the soak time of nets, seasonal effects on catch per effort, and the confounding effects of effort targeted at lake whitefish Coregonus clupeaformis—were not accounted for. We developed new indices of historic lean lake trout abundance that correct for these biases and compared them with the assessment data from 1984 to 1998 in Michigan waters of Lake Superior. The modern (1984–1998) abundance of wild lean lake trout is at least as high as that during 1929–1943 in six of eight management areas but lower in one area. Measures to promote and protect naturally reproducing populations have been more successful than previously realized.

Distribution, abundance, and biology of the alewife in U.S. waters of Lake Superior

USGS Publications Warehouse

Bronte, Charles R.; Selgeby, James H.; Curtis, Gary L.

1991-01-01

Alewives (Alosa pseudoharengus) were first reported in Lake Superior in 1954 and gradually increased in abundance in the late 1950s. In the 1960s and early 1970s, the fish were widespread in the lake but scarce. We determined the more recent abundance and distribution of alewives by cross-contour trawling in the spring in 1978–1988. Alewives were scarce lake-wide; the mean catch rate was only 23 fish per 100 h of trawling and represented a density of 0.003 kg per hectare in the area swept by the trawls. Fish of six age groups were caught in trawls in spring and gill nets in fall in 1983–1987. Total annual mortality was 64%, a high natural rate in the absence of fishing. Alewives in Lake Superior were small at the end of their first growing season but later grew faster than those in the other Great Lakes. Fecundity, estimated to be 64,000 eggs (mean total length = 187 mm) was higher than in other freshwater stocks. Zooplankton was the major food of alewives < 100 mm long and Mysis was the main food of larger fish. Exposure to water temperatures below lethal minimums for overwintering fish and for developing eggs limits the success of this species in Lake Superior.

46 CFR 401.410 - Basic rates and charges on Lakes Huron, Michigan and Superior and the St. Mary's River.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Superior and the St. Mary's River. 401.410 Section 401.410 Shipping COAST GUARD (GREAT LAKES PILOTAGE... Services § 401.410 Basic rates and charges on Lakes Huron, Michigan and Superior and the St. Mary's River... performed by U.S. registered pilots on Lakes Huron, Michigan, and Superior and the St. Mary's River. (a...

Osteological evidence of genetic divergence of lake trout (Salvelinus namaycush) in Lake Superior

USGS Publications Warehouse

Burnham-Curtis, Mary K.; Smith, Gerald R.

1994-01-01

Three phenotypes of Salvelinus namaycush in Lake Superior, the lean, siscowet, and bumper, are traditionally identified primarily by fat content and body shape. Their taxonomic status is in question because of intermediates as well as the possibility that the diagnostic characters are ecophenotypic. Two osteological characters, the dorsal opercular notch (first recorded by Agassiz in his description of the siscowet) and radii on the anterodorsal part of the supraethmoid, differ between most leans and siscowets. The notch in the opercle near its articulation with the hyomandibular bone is present in humpers, usually present in siscowets, and usually absent in leans. Radii on the anterodorsal surface of the supraethmoid bone usually are found in siscowets and humpers but usually are absent in leans. The correlations among these characters and other features of the phenotype indicate a significant level of differentiation between the three phenotypes. Available evidence suggests that the differentiation is genetic. The frequency of mixed phenotypes is evidence of limited gene flow among the phenotypes. The siscowet and humper phenotypes apparently originated in Lake Superior in postglacial time.

Comparison of Radiocarbon Ages of Sediments, Plants, and Shells From Coastal Lakes in North Florida

NASA Astrophysics Data System (ADS)

Wang, Y.; Das, O.; Liu, J.; Xu, X.; Roy, R.; Donoghue, J. F.; Means, G. H.

2017-12-01

Coastal lakes sediments are valuable archives of paleo-hurricanes and environmental changes during the late Quaternary provided that they can be accurately dated. Here, we report new radiocarbon (14C) dates derived from various organic and inorganic substrates, including bulk sediment organic matter, plants, shells, particulate organic matter (POM) and dissolved organic matter (DOM), from three coastal lakes in Florida, and compare these ages to evaluate the "reservoir effect" on 14C dating of both organic and inorganic carbon in these lakes. Bulk sediment organic matter yielded consistently older 14C ages than contemporaneous plants and shell fragments, indicating significant radiocarbon deficiencies in sedimentary organic matter in these coastal lakes, caused by influx of old organic carbon from terrestrial sources (such as soils and ancient peat deposits) in the watershed. Several reversals are observed in the 14C ages of bulk sediment organic matter in sediment cores from these lakes, indicating that input of aged organic matter from terrestrial sources into these lakes can vary considerably over time. DOM and POM samples collected at different times also yielded variable 14C signatures, further confirming the temporal variability in the contribution of old organic carbon from terrestrial sources to the lakes. The 14C age discrepancy between bulk sediment organic matter and co-occurring plant fragments or shells varies from less than one hundred years to nearly three thousand years in sediment cores examined in this study. The results show that 14C ages obtained from bulk sediment organic matter in these coastal lakes are unreliable. Analyses of both modern and fossil shells from one of the lakes suggest that the 14C reservoir effect on inorganic carbon in the lake is small and thus freshwater shells (if preserved in the sediment cores) may serve as a good substrate for 14C dating in the absence of plant fragments. However, unidentifiable shell fragments

A conceptual framework for Lake Michigan coastal/nearshore ecosystems, with application to Lake Michigan Lakewide Management Plan (LaMP) objectives

USGS Publications Warehouse

Seelbach, Paul W.; Fogarty, Lisa R.; Bunnell, David Bo; Haack, Sheridan K.; Rogers, Mark W.

2013-01-01

The Lakewide Management Plans (LaMPs) within the Great Lakes region are examples of broad-scale, collaborative resource-management efforts that require a sound ecosystems approach. Yet, the LaMP process is lacking a holistic framework that allows these individual actions to be planned and understood within the broader context of the Great Lakes ecosystem. In this paper we (1) introduce a conceptual framework that unifies ideas and language among Great Lakes managers and scientists, whose focus areas range from tributary watersheds to open-lake waters, and (2) illustrate how the framework can be used to outline the geomorphic, hydrologic biological, and societal processes that underlie several goals of the Lake Michigan LaMP, thus providing a holistic and fairly comprehensive roadmap for tackling these challenges. For each selected goal, we developed a matrix that identifies the key ecosystem processes within the cell for each lake zone and each discipline; we then provide one example where a process is poorly understood and a second where a process is understood, but its impact or importance is unclear. Implicit in these objectives was our intention to highlight the importance of the Great Lakes coastal/nearshore zone. Although the coastal/nearshore zone is the important linkage zone between the watershed and open-lake zones—and is the zone where most LaMP issues are focused--scientists and managers have a relatively poor understanding of how the coastal/nearshore zone functions. We envision follow-up steps including (1) collaborative development of a more detailed and more complete conceptual model of how (and where) identified processes are thought to function, and (2) a subsequent gap analysis of science and monitoring priorities.

The contamination of Lake Superior with amphibole gangue minerals.

PubMed

Langer, A M; Maggiore, C M; Nicholson, W J; Rohl, A N; Rubin, I B; Selikoff, I J

1979-01-01

Iron ore called taconite is mined in the Biwabik Iron Formation in the Eastern Mesabi region of the Mesabi Range, in eastern Minnesota. After mining, ore is shipped to Silver Bay, Minnnesota for processing and wet magnetic extraction. Tailings from the process are dumped, as a slurry, into a man-made containment delta constructed in Lake Superior. Submicroscopic amphibole fibers and/or cleavage fragments, a component of the gangue, apparently escape from the delta at Silver Bay, and enter Lake Superior. These particles contaiminate the potable water supplies of municipalities drawing directly from the lake. One of the gangue minerals is the amphibole grunerite, whose asbestiform variety is called amosite. Major emphasis of this study was directed at identification of submicroscopic particle pollutants, based on morphology, structure and chemical composition. Quantitative determination of fibrous amphibole phases, present in a range of water samples, was undertaken. Transmission electron microscopy, selected area electron diffraction, and an electron microprobe technique was used for identification and enumeration and this information was compared with data sets determined from standards. Grunerite fiber and/or acicular cleavage fragments, in some instances indistinguishable from asbestiform grunerite, are present in the tailings, lake water and drinking water of a number of municipalities, a result of contamination of the lake at the Silver Bay milling operation. This amphibole is found in drinking water in concentrations which range from 0.6 to 2.8 X 10(6) fiber/liter. The risk to health, associated with direct ingestion of grunerite fiber is unknown and is extrapolated from the asbestiform grunerite (amosite) data base. The biological activity of other fibrous amphiboles observed, unrelated to any asbestiform silicate variety, is presently unknown and warrants investigation.

Decline of lake herring (Coregonus artedii) in Lake Superior: an analysis of the Wisconsin herring fishery, 1936-78

USGS Publications Warehouse

Selgeby, James H.

1982-01-01

Annual harvests of lake herring (Coregonus artedii) in American waters of Lake Superior declined from an average of 2 million kg in 1936–62 to less than 25 000 kg in 1978. Analysis of commercial fishing records revealed that the sequential overexploitation of discrete unit stocks caused the collapse of the herring population in Wisconsin waters. In each of six major spawning areas, catch exceeded the productive capacity of the stock and the stock failed. Because stocks in the six areas were exploited sequentially, mostly in groups of two or three simultaneously, the demise of the stocks was not readily apparent until the last two failed in the early 1960s. After the collapse of the last major spawning stock, the fishery dwindled but may have continued to overexploit the remaining small stocks. The residual populations were apparently able only to replace themselves. Some form of density-independent mortality was apparently operating to prevent their recovery during the 1960s and 1970s.Key words: lake herring, overfishing, Lake Superior

Physiological modifications of seston in response to physicochemical gradients within Lake Superior (presentation)

EPA Science Inventory

We show for the first time the importance of plankton producing non-phosphorus lipids as a strategy for reducing cellular P inventories in Lake Superior. In September 2011, we investigated the distribution of dissolved and particulate phosphorus (PP) pools throughout the lake. Av...

Trophic connections in Lake Superior Part I: the offshore fish community

USGS Publications Warehouse

Gamble, A.E.; Hrabik, T.R.; Stockwell, J.D.; Yule, D.L.

2011-01-01

Detailed diet linkages within the offshore (> 80 m bathymetric depth) food web of Lake Superior are currently not well identified. We used analyses of fish stomach contents to create an empirically based food web model of the Lake Superior offshore fish community. Stomachs were collected seasonally (spring, summer, and fall) from nine offshore locations in 2005, using bottom and midwater trawls. In total, 2643 stomachs representing 12 fish species were examined. The predominant fish species collected were deepwater sculpin (Myoxocephalus thompsonii), siscowet (Salvelinus namaycush siscowet), kiyi (Coregonus kiyi), and cisco (Coregonus artedi). Mysis diluviana was the most common prey item, indicating that changes in Mysis abundance could have a profound impact on the entire offshore food web. Mysis was the primary diet item of deepwater sculpin (≥ 53% by mass) and kiyi (≥ 96% by mass) regardless of depth or season. The invasive Bythotrephes was an important diet component of the pelagic cisco in summer and fall. Deepwater sculpin were the primary diet item of siscowet (≥ 52% by mass), with coregonines appearing in the diet of larger (> 400 mm) siscowet. Non-metric multidimensional scaling analysis indicated that there were no statistically significant seasonal or site-specific differences in diets of deepwater sculpin, cisco, or kiyi. Site was the primary structuring factor in siscowet diets. Generally, in Lake Superior, the diet items of the dominant offshore species did not appear to be in danger from those types of major ecological shifts occurring in the lower Laurentian Great Lakes.

Wave Action and Breakwater Location, Taconite Harbor (Two Islands), Lake Superior, Minnesota: Hydraulic Model Investigation

DTIC Science & Technology

1955-05-01

president, Taconite Contractors, Erie. Mining Company, Duluth, Minnesota The model study was conducted in the Hydraulics Division of the Waterways...CORPS OF ENGINEERS. U. S. ARMY WAVE ACTION AND BREAKWATER LOCATION TACONITE HARBOR (TWO ISLANDS) LAKE SUPERIOR, MINNESOTA ARIIIY-MRC VICKSBURG...Breakwater Location, Taconite Harbor (Two Islands), Lake Superior, Minnesota : Hydraulic Model Investigation 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

Connecting Indigenous Knowledge to Thaw Lake Cycle Research on the Arctic Coastal Plain of Alaska

NASA Astrophysics Data System (ADS)

Eisner, W. R.; Cuomo, C. J.; Hinkel, K. M.; Jones, B. M.; Hurd, J.

2005-12-01

Thaw lakes cover about 20% of the Arctic Coastal Plain of Alaska. Another 26% is scarred by basins that form when lakes drain, and these drained thaw-lake basins are sites for preferential carbon accumulation as plant biomass. Recent studies in the continuous permafrost zone of Western Siberia suggest that lakes have been expanding in the past several decades in response to regional warming. Anticipated regional warming would likely mobilize sequestered soil organic carbon, resulting in the emission of CO2 and CH4. Our understanding of the processes leading to thaw lake formation, expansion, and drainage in northern Alaska has been limited because models are specific to the flat, young Outer (seaward) Coastal Plain comprising 1/3 of the region. Furthermore, spatial and temporal analysis of lake dynamics is largely restricted to the period since 1948, when aerial photographs first became available across large regions of the Coastal Plain. In order to fill these gaps, we have been interviewing Iñupiaq elders, hunters, and berry pickers from the villages of Atqasuk and Barrow. The objective of these interviews is to obtain accounts of lake formation, expansion and drainage that have occurred within living or oral memory, and extend the record back several generations. To date, we have interviewed fifteen Iñupiat; most of these are people who travel the tundra frequently and have done so for decades. They have first-hand experience of lake drainage, sea cliff and river bank erosion, permafrost degradation, and other landscape changes. Many informants expressed concern that landscape changes are occurring at an increasingly rapid rate. They have identified lakes that have drained, areas where the permafrost is thawing, and places where the sea and river coastline is eroding. We have been able to corroborate reports of lake drainage from our informants with a series of aerial photographs, satellite images, and radiocarbon dates. In many instances, the elders have

Coastal lake sediments reveal 5500 years of tsunami history in south central Chile

NASA Astrophysics Data System (ADS)

Kempf, Philipp; Moernaut, Jasper; Van Daele, Maarten; Vandoorne, Willem; Pino, Mario; Urrutia, Roberto; De Batist, Marc

2017-04-01

We present an exceptionally long and continuous coastal lacustrine record of ∼5500 years from Lake Huelde on the west coast of Chiloé Island in south central Chile. The study area is located within the rupture zone of the giant 1960 CE Great Chilean Earthquake (MW 9.5). The subsequent earthquake-induced tsunami inundated Lake Huelde and deposited mud rip-up clasts, massive sand and a mud cap in the lake. Long sediment cores from 8 core sites within Lake Huelde reveal 16 additional sandy layers in the 5500 year long record. The sandy layers share sedimentological similarities with the deposit of the 1960 CE tsunami and other coastal lake tsunami deposits elsewhere. On the basis of general and site-specific criteria we interpret the sandy layers as tsunami deposits. Age-control is provided by four different methods, 1) 210Pb-dating, 2) the identification of the 137Cs-peak, 3) an infrared stimulated luminescence (IRSL) date and 4) 22 radiocarbon dates. The ages of each tsunami deposit are modelled using the Bayesian statistic tools of OxCal and Bacon. The record from Lake Huelde matches the 8 regionally known tsunami deposits from documented history and geological evidence from the last ∼2000 years without over- or underrepresentation. We extend the existing tsunami history by 9 tsunami deposits. We discuss the advantages and disadvantages of various sedimentary environments for tsunami deposition and preservation, e.g. we find that Lake Huelde is 2-3 times less sensitive to relative sea-level change in comparison to coastal marshes in the same region.

Tsunami-induced morphological change of a coastal lake: comparing hydraulic experiment with numerical modeling

NASA Astrophysics Data System (ADS)

Sugawara, D.; Imai, K.; Mitobe, Y.; Takahashi, T.

2016-12-01

Coastal lakes are one of the promising environments to identify deposits of past tsunamis, and such deposits have been an important key to know the recurrence of tsunami events. In contrast to tsunami deposits on the coastal plains, however, relationship between deposit geometry and tsunami hydrodynamic character in the coastal lakes has poorly been understood. Flume experiment and numerical modeling will be important measures to clarify such relationship. In this study, data from a series of flume experiment were compared with simulations by an existing tsunami sediment transport model to examine applicability of the numerical model for tsunami-induced morphological change in a coastal lake. A coastal lake with a non-erodible beach ridge was modeled as the target geomorphology. The ridge separates the lake from the offshore part of the flume, and the lake bottom was filled by sand. Tsunami bore was generated by a dam-break flow, which is capable of generating a maximum near-bed flow speed of 2.5 m/s. Test runs with varying magnitude of the bore demonstrated that the duration of tsunami overflow controls the scouring depth of the lake bottom behind the ridge. The maximum scouring depth reached up to 7 cm, and sand deposition occurred mainly in the seaward-half of the lake. A conventional depth-averaged tsunami hydrodynamic model coupled with the sediment transport model was used to compare the simulation and experimental results. In the Simulation, scouring depth behind the ridge reached up to 6 cm. In addition, the width of the scouring was consistent between the simulation and experiment. However, sand deposition occurred mainly in a zone much far from the ridge, showing a considerable deviation from the experimental results. This may be associated with the lack of model capability to resolve some important physics, such as vortex generation behind the ridge and shoreward migration of hydraulic jump. In this presentation, the results from the flume experiment and

The Quagga mussel invades the Lake Superior basin - journal article

EPA Science Inventory

Prior studies recognized the presence of a single dreissenid species in Lake Superior--the zebra mussel Dreissena polymorpha. However, taxonomic keys based on traditional shell morphology are not always able to differentiate dreissenid species with confidence. We thus employed ge...

Ontonagon Harbor Operation and Maintenance Activities. Lake Superior.

DTIC Science & Technology

1975-08-01

St. Paul, Minnesota 55101 August 1975 FINAL ENVIRONMENTAL IMPACT STATEMENT OPERATION AND MAINTENAN4CE ACTIVITIES ONTONAGON HARBDOR, MICHIGAN LAKE...SUPERIOR Responsible Office: St. Paul District, Corps of Engineers, 1135 U.S. Post Office and Custom House, St. Paul, Minnesota 55101 Telephone Number 612...Nonesuch shale is a finer siltstone containing recoverable copper deposits. Active mining is present at White Pine, 12 air miles southwest of Ontonagon

Effects of spatial allocation and parameter variability on lakewide estimates from surveys of Lake Superior, North America’s largest lake

EPA Science Inventory

Lake Superior was sampled in 2011 using a Generalized Random Tessellation Stratified design (n=54 sites) to characterize biological and chemical properties of this huge aquatic resource, with statistical confidence. The lake was divided into two strata (inshore <100m and offsh...

Coastal Water Quality Modeling in Tidal Lake: Revisited with Groundwater Intrusion

NASA Astrophysics Data System (ADS)

Kim, C.

2016-12-01

A new method for predicting the temporal and spatial variation of water quality, with accounting for a groundwater effect, has been proposed and applied to a water body partially connected to macro-tidal coastal waters in Korea. The method consists of direct measurement of environmental parameters, and it indirectly incorporates a nutrients budget analysis to estimate the submarine groundwater fluxes. Three-dimensional numerical modeling of water quality has been used with the directly collected data and the indirectly estimated groundwater fluxes. The applied area is Saemangeum tidal lake that is enclosed by 33km-long sea dyke with tidal openings at two water gates. Many investigations of groundwater impact reveal that 10 50% of nutrient loading in coastal waters comes from submarine groundwater, particularly in the macro-tidal flat, as in the west coast of Korea. Long-term monitoring of coastal water quality signals the possibility of groundwater influence on salinity reversal and on the excess mass outbalancing the normal budget in Saemangeum tidal lake. In the present study, we analyze the observed data to examine the influence of submarine groundwater, and then a box model is demonstrated for quantifying the influx and efflux. A three-dimensional numerical model has been applied to reproduce the process of groundwater dispersal and its effect on the water quality of Saemangeum tidal lake. The results show that groundwater influx during the summer monsoon then contributes significantly, 20% more than during dry season, to water quality in the tidal lake.

USGS capabilities for interdisciplinary investigations in coastal and nearshore ecosystems of the Great Lakes

USGS Publications Warehouse

Myers, Donna N.

2002-01-01

People choose to reside, work, and vacation in coastal areas of the Great Lakes because of the lakes' scenic beauty and their historic and cultural features. Great Lakes nearshore areas also constitute a valuable economic resource. Two million anglers added \\$1 billion to the region's economy in 1996. More than 300 million tons of goods were transported out of major Great Lakes ports at a value of \\$3 billion in 1996. A 1998 survey of Lake Erie beaches estimated contributions of $5 million per year to each local economy with a public beach. More than 70 million people yearly visit national, state and provincial parks in the Great Lakes area. Uncontrolled land development, recreational development, invasive species, climate change, water availability, and water-level changes and fluctuations lead a long list of current and potential issues in coastal and nearshore areas. To be effectively addressed, these complex issues require an interdisciplinary approach.

A new look at the Lake Superior biomass size-spectrum

EPA Science Inventory

We combined data from multiple sampling programs to describe the Lake Superior pelagic biomass size structure. The data represented phytoplankton, zooplankton and prey-fish that spanned over 10 orders of magnitude in size and two time periods separated by five years. The biomas...

AN INTEGRATED COASTAL-WATERSHED MONITORING FRAMEWORK FOR ASSESSMENT

EPA Science Inventory

An approach for watershed classification in support of assessments, disgnosis of biological impairment, and prioritization of watershed restorations has been tested in coastal watersheds surrounding the western arm of Lake Superior and is currently being assessed for a series of ...

The non-native faucet snail (Bithynia tentaculata) makes the leap to Lake Superior

EPA Science Inventory

The European-origin faucet snail (Bithynia tentaculata) has been present in the lower Great Lakes since the late 1800s but only very recently reached Lake Superior. Surveys from 2011 through 2013 found faucet snail to be abundant and wide-spread in the St. Louis River Estuary wi...

Habitat coupling in a large lake system: delivery of an energy subsidy by an offshore planktivore to the nearshore zone of Lake Superior

USGS Publications Warehouse

Stockwell, Jason D.; Yule, Daniel L.; Hrabik, Thomas R.; Sierszen, Michael E.; Isaac, Edmund J.

2014-01-01

1. We hypothesised that the autumn spawning migration of Lake Superior cisco (Coregonus artedi) provides a resource subsidy, in the form of energy-rich cisco eggs, from the offshore pelagic to the nearshore benthic community over winter, when alternate prey production is likely to be low. 2. We tested this hypothesis using fish and macroinvertebrate surveys, fish population demographics, diet and stable isotope analyses, and bioenergetics modelling. 3. The benthic, congeneric lake whitefish (C. clupeaformis) was a clear beneficiary of cisco spawning. Cisco eggs represented 16% of lake whitefish annual consumption in terms of biomass, but 34% of energy (because of their high energy density: >10 kJ g wet mass−1). Stable isotope analyses were consistent with these results and suggest that other nearshore fish species may also rely on cisco eggs. 4. The lipid content of lake whitefish liver almost doubled from 26 to 49% between November and March, while that of muscle increased from 14 to 26% over the same period, suggesting lake whitefish were building, rather than depleting, lipid reserves during winter. 5. In the other Laurentian Great Lakes, where cisco populations remain very low and rehabilitation efforts are underway, the offshore-to-nearshore ecological link apparent in Lake Superior has been replaced by non-native planktivorous species. These non-native species spawn in spring have smaller eggs and shorter incubation periods. The rehabilitation of cisco in these systems should reinstate the onshore subsidy as it has in Lake Superior.

Big Numbers for the Big Lake: A Lower Food Web Assessment of Lake Superior (2004-2006)

EPA Science Inventory

Our collaborative binational studies focused on lower trophic levels (plankton, mysids, benthos) of Lake Superior based on comprehensive sampling (2004 to 2006). Information is integrated for a lakewide summary, but also to display patterns among lower food web components by dept...

COASTAL WETLAND INSECT COMMUNITIES ALONG A TROPHIC GRADIENT IN GREEN BAY, LAKE MICHIGAN

EPA Science Inventory

Insects of Great Lakes coastal wetlands have received little attention in spite of their importance in food webs and sensitivity to anthropogenic stressors. We characterized insect communities from four coastal wetlands that spanned the length of a trophic gradient in Green Bay d...

Seasonal bathymetric distributions of 16 fishes in Lake Superior, 1958-75

USGS Publications Warehouse

Selgeby, James H.; Hoff, Michael H.

1996-01-01

The bathymetric distributions of fishes in Lake Superior, which is one of the largest and deepest lakes in the world, has not been studied on a lakewide scale. Knowledge about the bathymetric distributions will aid in designing fish sampling programs, estimating absolute abundances, and modeling energy flow in the lake. Seasonal bathymetric distributions were determined , by 10-m depth intervals, for 16 fishes collected with bottom trawls and bottom-set gill nets within the upper 150 m of Lake Superior during 1958-75. In spring trawl catches, maximum abundance occurred at these depths: 15 m for round whitefish (Prosopium cylindraceum); 25m for longnose sucker (Catostomus catostomus); 35 m for lake whitefish (Coregonus clupeaformis) and rainbow smelt (Osmerus mordax); 45 m for lake trout (Salvelinus namaycush); 65 m for pygmy whitefish (Prospoium coulteri) and bloater (Coregonus hoyi); 75 m for trout- perch (Percopsis omiscomaycus); 105 m for shortjaw cisco (Coregonus zenithicus); and 115 m for ninespine stickleback (Pungitius pungitius), burbot (Lota lota), slimy sculpin (Cottus cogantus), spoonhead sculpin (Cottus ricei), and deepwater sculpin (Myoxcephalus thompsoni). Bathymetric distributions in spring gill nets were similar to those in trawls, except that depths of maximum abundances in gill nets were shallower than those in trawls for lake trout, rainbow smelt, longnose sucker, and burbot. Lake herring (Coregonus artedi) and kiyi (Coregonus kiyi) were rarely caught in trawls, and their maximum abundances in spring gill net collections were at depths of 25 and 145 m, respectively. In summer, pygmy whitefish, shortjaw cisco, lake herring, kiyi, longnose sucker, burbot, ninespine stickleback, trout-perch, slimy sculpin, and spponhead sculpin were at shallower depths than in spring, whereas rainbow smelt were found in deeper water; there was no change for other species. In fall, shortjaw cisco was at shallower depths than in summer, whereas the remaining species

FIELD TESTS OF GEOGRAPHICALLY-DEPENDENT VS. THRESHOLD-BASED WATERSHED CLASSIFICATION SCHEMES IN THE GREAT LAKES BASIN

EPA Science Inventory

We compared classification schemes based on watershed storage (wetland + lake area/watershed area) and forest fragmentation with a geographically-based classification scheme for two case studies involving 1) Lake Superior tributaries and 2) watersheds of riverine coastal wetlands...

FIELD TESTS OF GEOGRAPHICALLY-DEPENDENT VS. THRESHOLD-BASED WATERSHED CLASSIFICATION SCHEMED IN THE GREAT LAKES BASIN

EPA Science Inventory

We compared classification schemes based on watershed storage (wetland + lake area/watershed area) and forest fragmentation with a geographically-based classification scheme for two case studies involving 1)Lake Superior tributaries and 2) watersheds of riverine coastal wetlands ...

Reestablishing a spawning population of lake trout in Lake Superior with fertilized eggs in artificial turf incubators

USGS Publications Warehouse

Bronte, Charles R.; Schram, Stephen T.; Selgeby, James H.; Swanson, Bruce L.

2002-01-01

Fertilized eggs from lake trout Salvelinus namaycush were placed in artificial turf incubators and deployed on Devils Island Shoal, Lake Superior, in an attempt to reestablish a spawning population on this once important spawning area. Efficacy was measured by the changes in catch rates, age composition, and origin of adult lake trout returning to the shoal in the fall in subsequent years. The abundance of lake trout spawners without fin clips, which implies that these fish hatched in the lake, increased throughout the sampling period, whereas the abundance of hatchery-reared fish (indicated by one or more fin clips) stocked for restoration purposes remained low. Year-class-specific stock-recruitment analysis suggested that the recruitment of unclipped spawners was related to the number of eggs planted in previous years rather than to spawning by the few adult lake trout visiting the reef. Increases in adult fish at Devils Island Shoal were independent of trends at adjacent sites, where unclipped spawner abundances remained low. Enhanced survival to hatch and apparent site imprinting of young lake trout make this technique a viable alternative to stocking fingerling and yearling lake trout to reestablish spawning populations on specific sites in the Great Lakes.

A new look at the Lake Superior biomass size spectrum

EPA Science Inventory

We synthesized data from multiple sampling programs and years to describe the Lake Superior pelagic biomass size structure for two time periods separated by 5 years. The data consisted of water analyzed on a Coulter counter for algae, in situ measurements with a laser optical pl...

Lake Superior Phytoplankton Characterization from the 2006 Probability Based Survey

EPA Science Inventory

We conducted a late summer probability based survey of Lake Superior in 2006 which consisted of 52 sites stratified across 3 depth zones. As part of this effort, we collected composite phytoplankton samples from the epilimnion and the fluorescence maxima (Fmax) at 29 of the site...

Methods to assess natural and anthropogenic thaw lake drainage on the western Arctic coastal plain of northern Alaska

USGS Publications Warehouse

Hinkel, Kenneth M.; Jones, Benjamin M.; Eisner, Wendy R.; Cuomo, Chris J.; Beck, R.A.; Frohn, R.

2007-01-01

Thousands of lakes are found on the Arctic Coastal Plain of northern Alaska and northwestern Canada. Developed atop continuous permafrost, these thaw lakes and associated drained thaw lake basins are the dominant landscape elements and together cover 46% of the 34,570 km2western Arctic Coastal Plain (WACP). Lakes drain by a variety of episodic processes, including coastal erosion, stream meandering, and headward erosion, bank overtopping, and lake coalescence. Comparison of Landsat multispectral scanner (MSS) imagery from the mid-1970s to Landsat 7 enhanced thematic mapper (ETM+) imagery from around 2000 shows that 50 lakes completely or partially drained over the approximately 25 year period, indicating landscape stability. The lake-specific drainage mechanism can be inferred in some cases and is partially dependant on geographic settings conducive to active erosion such as riparian and coastal zones. In many cases, however, the cause of drainage is unknown. The availability of high-resolution aerial photographs for the Barrow Peninsula extends the record back to circa 1950; mapping spatial time series illustrates the dynamic nature of lake expansion, coalescence, and drainage. Analysis of these historical images suggests that humans have intentionally or inadvertently triggered lake drainage near the village of Barrow. Efforts to understand landscape processes and identify events have been enhanced by interviewing Iñupiaq elders and others practicing traditional subsistence lifestyles. They can often identify the year and process by which individual lakes drained, thereby providing greater dating precision and accuracy in assessing the causal mechanism. Indigenous knowledge has provided insights into events, landforms, and processes not previously identified or considered.

The Penokean orogeny in the Lake Superior region

USGS Publications Warehouse

Schulz, K.J.; Cannon, W.F.

2007-01-01

The Penokean orogeny began at about 1880 Ma when an oceanic arc, now the Pembine-Wausau terrane, collided with the southern margin of the Archean Superior craton marking the end of a period of south-directed subduction. The docking of the buoyant craton to the arc resulted in a subduction jump to the south and development of back-arc extension both in the initial arc and adjacent craton margin to the north. A belt of volcanogenic massive sulfide deposits formed in the extending back-arc rift within the arc. Synchronous extension and subsidence of the Superior craton resulted in a broad shallow sea characterized by volcanic grabens (Menominee Group in northern Michigan). The classic Lake Superior banded iron-formations, including those in the Marquette, Gogebic, Mesabi and Gunflint Iron Ranges, formed in that sea. The newly established subduction zone caused continued arc volcanism until about 1850 Ma when a fragment of Archean crust, now the basement of the Marshfield terrane, arrived at the subduction zone. The convergence of Archean blocks of the Superior and Marshfield cratons resulted in the major contractional phase of the Penokean orogeny. Rocks of the Pembine-Wausau arc were thrust northward onto the Superior craton causing subsidence of a foreland basin in which sedimentation began at about 1850 Ma in the south (Baraga Group rocks) and 1835 Ma in the north (Rove and Virginia Formations). A thick succession of arc-derived turbidites constitutes most of the foreland basin-fill along with lesser volcanic rocks. In the southern fold and thrust belt tectonic thickening resulted in high-grade metamorphism of the sediments by 1830 Ma. At this same time, a suite of post-tectonic plutons intruded the deformed sedimentary sequence and accreted arc terranes marking the end of the Penokean orogeny. The Penokean orogen was strongly overprinted by younger tectonic and thermal events, some of which were previously ascribed to the Penokean. Principal among these was a

Epiphytic invertebrate patterns in coastal lakes along a gradient of salinity and water exchange with the sea

NASA Astrophysics Data System (ADS)

Obolewski, Krystian; Bąkowska, Martyna

2017-10-01

The species composition and abundance of epiphytic fauna inhabiting common reed (Phragmites australis (Cav.) Trin. ex Steud.) was performed in five coastal lakes in Słowiński National Park (southern Baltic coast in northern Poland). The lakes represent a salinity gradient (from freshwater to β-oligohaline waters) and four types of coastal lakes: (1) lagoon, L (Lake Łebsko, seawater enters it permanently); (2) coastal lake with periodically brackish water, CLB (Lake Gardno); (3) freshwater costal lake, CLF (Lake Smołdzińskie); and (4) coastal dune lakes, CLD (Dołgie Wielkie and Dołgie Małe). Using statistical ordination techniques, we found that the structure of epiphytic fauna (microinvertebrates and macroinvertebrates) is determined primarily by hydrological connectivity (water exchange) with the sea. Canonical Correspondence Analysis, coupled with variance partitioning, showed that hydrological connectivity accounted for 24% of the variation in the invertebrate community, followed by physico-chemical (19%) and trophic (8%) factors. Our results indicate that the assemblages of Ciliata-libera and Cnidaria are characteristic for L (β-oligohaline), Rotifera, Suctoria, Chaetogaster sp., Gastropoda and Trichoptera are characteristic for CLB (limnetic/β-oligohaline), but no taxonomic groups are characteristic for CLF and CLD (both limnetic). The index of multivariate dispersion showed a decreasing trend with the increasing lake isolation from the open sea, except for CLD. However, in terms of the structure of epiphytic fauna, Multi-Response Permutation Procedures showed that CLD significantly differed only from CLB. Our results suggest that the identified characteristic taxonomic groups of plant-associated macroinvertebrates have a high potential to be used as bioindicators of salinity and water exchange with the sea, due to their sensitivity to environmental stress.

Depth-specific Analyses of the Lake Superior Food Web, oral presentation

EPA Science Inventory

Characteristics of large, deep aquatic systems include depth gradients in community composition, in the quality and distribution of food resources, and in the strategies that organisms use to obtain their nutrition. In Lake Superior, nearshore communities that rely upon a combina...

Variability in physical and biological exchange among coastal wetlands and their adjacent Great Lakes

EPA Science Inventory

Hydrology is a major governor of physically-driven exchange among coastal wetlands and the adjacent Great Lake, whereas fish movement is a major governor of biologically-driven exchange. We use data describing coastal wetland morphology, hydrology, water quality, and fish tissue...

Estimation of invertebrate production from patterns of fish predation in western Lake Superior

USGS Publications Warehouse

Johnson, Timothy B.; Mason, Doran M.; Bronte, Charles R.; Kitchell, James F.

1998-01-01

We used bioenergetic models for lake herring Coregonus artedi, bloater Coregonus hoyi, and rainbow smelt Osmerus mordax to estimate consumption of zooplankton,Mysis, andDiporeia in western Lake Superior for selected years between 1978 and 1995. Total invertebrate biomass consumed yearly ranged from 2.5 to 38 g/m2 with nearly 40% consumed between August and October in all years. Copepod zooplankton represented the largest proportion of biomass collectively consumed by the three species (81%), although rainbow smelt consumed almost twice as much Mysis as zooplankton. Growth efficiency was highest for rainbow smelt (3.84–16.64%) and lower for the coregonids (1.91–12.26%). In the absence of quantitative secondary production values, we suggest our estimates of predatory demand provide a conservative range of the minimum invertebrate production in western Lake Superior during the past 20 years.

Late Holocene lake-level variation in southeastern Lake Superior: Tahquamenon Bay, Michigan

USGS Publications Warehouse

Johnston, John W.; Baedke, Steve J.; Booth, Robert K.; Thompson, Todd A.; Wilcox, Douglas A.

2004-01-01

Internal architecture and ages of 71 beach ridges in the Tahquamenon Bay embayment along the southeastern shore of Lake Superior on the Upper Peninsula of Michigan were studied to generate a late Holocene relative lake-level curve. Establishing a long-term framework is important to examine the context of historic events and help predict potential future changes critical for effective water resource management. Ridges in the embayment formed between about 4,200 and 2,100 calendar years before 1950 (cal. yrs. B.P.) and were created and preserved every 28 A? 4.8 years on average. Groups of three to six beach ridges coupled with inflections in the lake-level curve indicate a history of lake levels fluctuations and outlet changes. A rapid lake-level drop (approximately 4 m) from about 4,100 to 3,800 cal. yrs. B.P. was associated with a fall from the Nipissing II high-water-level phase. A change from a gradual fall to a slight rise was associated with an outlet change from Port Huron, Michigan/Sarnia, Ontario to Sault Ste. Marie, Michigan/Ontario. A complete outlet change occurred after the Algoma high-water-level phase (ca. 2,400 cal. yrs. B.P.). Preliminary rates of vertical ground movement calculated from the strandplain are much greater than rates calculated from historical and geologic data. High rates of vertical ground movement could have caused tectonism in the Whitefish Bay area, modifying the strandplain during the past 2,400 years. A tectonic event at or near the Sault outlet also may have been a factor in the outlet change from Port Huron/Sarnia to Sault Ste. Marie.

Nutrient sequestration in Aquitaine lakes (SW France) limits nutrient flux to the coastal zone

NASA Astrophysics Data System (ADS)

Buquet, Damien; Anschutz, Pierre; Charbonnier, Céline; Rapin, Anne; Sinays, Rémy; Canredon, Axel; Bujan, Stéphane; Poirier, Dominique

2017-12-01

Oligotrophic coastal zones are disappearing from increased nutrient loading. The quantity of nutrients reaching the coast is determined not only by their original source (e.g. fertilizers used in agriculture, waste water discharges) and the land use, but also by the pathways through which nutrients are cycled from the source to the river mouth. In particular, lakes sequester nutrients and, hence, reduce downstream transfer of nutrients to coastal environments. Here, we quantify the impact of Aquitaine great lakes on the fluxes of dissolved macro-nutrients (N, P, Si) to the Bay of Biscay. For that, we have measured nutrient concentrations and fluxes in 2014 upstream and downstream lakes of Lacanau and Carcans-Hourtin, which belongs to the catchment of the Arcachon Bay, which is the largest coastal lagoon of the Bay of Biscay French coast. Data were compared to values obtained from the Leyre river, the main freshwater and nutrient source for the lagoon. Results show that processes in lakes greatly limit nutrient flux to the lagoon compared to fluxes from Leyre river, although the watershed is similar in terms of land cover. In lakes, phosphorus and silicon are trapped for long term in the sediment, silicon as amorphous biogenic silica and phosphorus as organic P and P associated with Fe-oxides. Nitrogen that enters lakes mostly as nitrate is used for primary production. N is mineralized in the sediment; a fraction diffuses as ammonium. N2 production through benthic denitrification extracts only 10% of dissolved inorganic nitrogen from the aquatic system. The main part is sequestered in organic-rich sediment that accumulates below 5 m depth in both lakes.

Life histories and abundance of crustacean zooplankton in the outlet of Lake Superior, 1971-72

USGS Publications Warehouse

Selgeby, James H.

1975-01-01

In sampling throughout a year, at about 3-wk intervals, of the crustacean zooplankton discharged from Lake Superior through the St. Marys River, 30 species were collected, including three not previously recorded for the lake: the copepod Cyclops strenuus, and the cladocerans Alona costata and Alonella acutirostris. Five copepods, Cyclops bicuspidatus thomasi, Diaptomus ashlandi, D. sicilis, Limnocalanus macrurus, and Senecella calanoides were present in the plankton throughout the year while three other copepods, Diaptomus minutus, Epischura lacustris, and Mesocyclops edax, along with all cladocerans, were present only during summer and fall. Five species of copepods, Diaptomus sicilis, D. minutus, Limnocalanus macrurus, Senecella calanoides, and Epischura lacustris produced a single generation annually; three other copepods and all cladocerans produced two or more generations. All species breed 1-3 mo later in Lake Superior than in lakes Michigan and Erie.

Status of the amphipod Diporeia ssp. in coastal waters of the Laurentian Great Lakes

EPA Science Inventory

Diporeia has historically been the dominant benthic macroinvertebrate in deeper waters of the Laurentian Great Lakes, and its abundance has been proposed as an indicator of ecological condition. In 2010, the USEPA incorporated the Great Lakes into the National Coastal Condition A...

Fish assemblages, connectivity, and habitat rehabilitation in a diked Great Lakes coastal wetland complex

USGS Publications Warehouse

Kowalski, Kurt P.; Wiley, Michael J.; Wilcox, Douglas A.

2014-01-01

Fish and plant assemblages in the highly modified Crane Creek coastal wetland complex of Lake Erie were sampled to characterize their spatial and seasonal patterns and to examine the implications of the hydrologic connection of diked wetland units to Lake Erie. Fyke netting captured 52 species and an abundance of fish in the Lake Erie–connected wetlands, but fewer than half of those species and much lower numbers and total masses of fish were captured in diked wetland units. Although all wetland units were immediately adjacent to Lake Erie, there were also pronounced differences in water quality and wetland vegetation between the hydrologically isolated and lake-connected wetlands. Large seasonal variations in fish assemblage composition and biomass were observed in connected wetland units but not in disconnected units. Reestablishment of hydrologic connectivity in diked wetland units would allow coastal Lake Erie fish to use these vegetated habitats seasonally, although connectivity does appear to pose some risks, such as the expansion of invasive plants and localized reductions in water quality. Periodic isolation and drawdown of the diked units could still be used to mimic intermediate levels of disturbance and manage invasive wetland vegetation.

SPATIAL PATTERNS IN ASSEMBLAGE STRUCTURES OF PELAGIC FORAGE FISH AND ZOOPLANKTON IN WESTERN LAKE SUPERIOR

EPA Science Inventory

This manuscript reports on the spatial distribution of zooplankton and forage fish in western Lake Superior. Fish and zooplankton assemblages are shown to differ substantially in abundance and size structure both between the open lake and nearshore regions and between two differe...

Age, growth, maturity, and fecundity of 'humper' lake trout, Isle Royale, Lake Superior

USGS Publications Warehouse

Rahrer, Jerold F.

1965-01-01

Humper lake trout are one of the several races or subpopulations of lake trout in Lake Superior. This study is based on 3,705 fish collected on a reef south of Isle Royale near the eastern end. The mean lengths of humper trout from commercial gill nets were smaller than those of lean lake trout. Members of age-groups VII, VIII, and IX represented 81.5 per cent of the commercial humper catch. The body-scale relation was described by two intersecting straight lines. The weight of humper trout increased as the 3.282 power of the length. Growth in length was slow and ranged from 1.6 to 3.5 inches per year. Annual increments were greatest in the first, sixth, and seventh years. Growth in weight was also slow but increased each year. Humper trout became legal (1 1/2 pounds) in the eighth year of life and reached 5 pounds in 11 years. All fish longer than 19.1 inches and older than age-group VIII were mature; the shortest mature fish were: males, 12.7 inches; females, 14.7 inches. At minimum legal size, 98 per cent of the males and 56 per cent of the females were mature. Humper trout produced an average of 1,351 eggs per fish or 516 per pound.

Organochlorine compounds in Lake Superior: Chiral polychlorinated biphenyls and biotransformation in the aquatic food web

USGS Publications Warehouse

Wong, Charles S.; Mabury, Scott A.; Whittle, D. Michael; Backus, Sean M.; Teixeira, Camilla; DeVault, David S.; Bronte, Charles R.; Muir, Derek C.G.

2004-01-01

The enantiomeric composition of seven chiral PCB congeners was measured in the Lake Superior aquatic food web sampled in 1998, to determine the extent of enantioselective biotransformation in aquatic biota. All chiral PCB congeners studied (CBs 91, 95, 136, 149, 174, 176, and 183) biomagnified in the Lake Superior aquatic food web, based on biomagnification and food web magnification factors greater than unity. PCB atropisomers were racemic in phytoplankton and zooplankton, suggesting no biotransformation potential toward PCBs for these low trophic level organisms. However, Diporeia and mysids had significantly nonracemic residues for most chiral congeners studied. This observation suggests that these macrozooplankton can stereoselectively metabolize chiral congeners. Alternatively, macrozooplankton obtained nonracemic residues from feeding on organic-rich suspended particles and sediments, which would imply that stereoselective microbial PCB biotransformation may be occurring in Lake Superior sediments at PCB concentrations far lower than that previously associated with such activity. Widely nonracemic PCB residues in forage fish (lake herring, rainbow smelt, and slimy sculpin) and lake trout suggest a combination of both in vivo biotransformation and uptake of nonracemic residues from prey for these species. Minimum biotransformation rates, calculated from enantiomer mass balances between predators and prey, suggest metabolic half-lives on the order of 8 yr for CB 136 in lake trout and 2.6 yr for CB 95 in sculpins. This result suggests that significant biotransformation may occur for metaboliz able PCB congeners over the lifespan of these biota. This study highlights the potential of chiral analysis to study biotransformation processes in food webs.

MERCURY IN STAMP SAND DISCHARGES: IMPLICATIONS FOR LAKE SUPERIOR MERCURY CYCLING

EPA Science Inventory

Approximately a half billion tons of waste rock from the extraction of native copper and silver ores was discharged into the Lake Superior basin. Stamping was the method of choice to recover these metals from the surrounding poor rock. This process created large amounts of extre...

Food of young-of-the-year lake trout (Salvelinus namaycush) in Presque Isle Harbor, Lake Superior

USGS Publications Warehouse

Swedberg, Donald V.; Peck, James W.

1984-01-01

The food habits of young lake trout (Salvelinus namaycush) were studied by examining the digestive tracts of 293 young-of-the-year collected in Presque Isle Harbor, Lake Superior. Lake trout in the 25 to 27-mm length range started to eat food organisms before all of their yolk material was absorbed. Organisms consumed by the 25 to 27-mm young-of-the-year included Chironomidae, Copepoda (Harpacticoida, Calanoida, Cyclopoida), and Cladocerea (Daphnia spp., Bosmina sp., Chydorus sp.). Chironomid pupae and chironomid larvae accounted for 74% and 5%, respectively, of the total volume of food eaten by the young lake trout in Presque Isle Harbor. Although copepods, cladocerans, and mysids were present in many stomachs, their contribution to the total volume of food was only 15%. Some lake trout in the 32 to 54-mm length range had consumed fry of sculpin (Cottus spp.) or rainbow smelt (Osmerus mordax), but the overall contribution of fish fry to the total volume of food was only 4% (frequency of occurrence, 10%). The lake trout in Presque Isle Harbor fed heavily on planktonic organisms, sparingly on benthic organisms, and were opportunistic feeders that appeared to prey on whatever forage organisms were available in the shallow nearshore waters.

The biological pump and lower trophic level controls on carbon cycling in Lake Superior: Insights from a multi-pronged study

NASA Astrophysics Data System (ADS)

Schreiner, K. M.; Bramburger, A.; Ozersky, T.; Sheik, C.; Steinman, B. A.

2016-02-01

Lake Superior is the largest freshwater lake in the world, supporting economically important fisheries and providing drinking water to hundreds of thousands of people. In recent decades, summer surface water temperature and the intensity and duration of water column stratification in the lake has increased steadily. These physical changes have resulted in significant perturbations to lower trophic level ecosystem characteristics. Recent observations of Great Lakes plankton assemblages have revealed multi-decadal patterns of community reorganization, with increased relative abundance of taxa characteristic of warmer waters. These changes, coupled with changing nutrient concentrations and colonization by non-native taxa, threaten to shift trophic structure and carbon dynamics at the bottom of the food web. To this end, this study seeks to quantify the impacts of this ecosystem shift on carbon fixation, the biological pump, and organic carbon cycling in Lake Superior. Utilizing a combined sampling approach, in the summer of 2015 we collected water, sediment, and biological samples across a nearshore-to-offshore gradient in the western arm of Lake Superior. Analyses included the community composition of bacteria, archaea, phytoplankton, and zooplankton; water column carbon and nutrient speciation; algal pigments and pigment degradation products; and net primary productivity. The collection of surface sediments allowed for additional assessment of benthic-pelagic coupling. The novel combination of this wide-ranging set of analyses to a locally and globally important water body like Lake Superior allowed us to fully assess the interactions between lower trophic level biology and carbon and nutrient cycling throughout the water column. Preliminary data indicates that microbial community composition was variable across the western arm of Lake Superior and showed signs of stratification at individual stations (>100 m deep). Sample collection occurred soon after lake

Sustainability of the Lake Superior fish community: Interactions in a food web context

USGS Publications Warehouse

Kitchell, James F.; Cox, Sean P.; Harvey, Chris J.; Johnson, Timothy B.; Mason, Doran M.; Schoen, Kurt K.; Aydin, Kerim; Bronte, Charles; Ebener, Mark; Hansen, Michael; Hoff, Michael; Schram, Steve; Schreiner, Don; Walters, Carl J.

2000-01-01

The restoration and rehabilitation of the native fish communities is a long-term goal for the Laurentian Great Lakes. In Lake Superior, the ongoing restoration of the native lake trout populations is now regarded as one of the major success stories in fisheries management. However, populations of the deepwater morphotype (siscowet lake trout) have increased much more substantially than those of the nearshore morphotype (lean lake trout), and the ecosystem now contains an assemblage of exotic species such as sea lamprey, rainbow smelt, and Pacific salmon (chinook, coho, and steelhead). Those species play an important role in defining the constraints and opportunities for ecosystem management. We combined an equilibrium mass balance model (Ecopath) with a dynamic food web model (Ecosim) to evaluate the ecological consequences of future alternative management strategies and the interaction of two different sets of life history characteristics for fishes at the top of the food web. Relatively rapid turnover rates occur among the exotic forage fish, rainbow smelt, and its primary predators, exotic Pacific salmonids. Slower turnover rates occur among the native lake trout and burbot and their primary prey—lake herring, smelt, deepwater cisco, and sculpins. The abundance of forage fish is a key constraint for all salmonids in Lake Superior. Smelt and Mysis play a prominent role in sustaining the current trophic structure. Competition between the native lake trout and the exotic salmonids is asymmetric. Reductions in the salmon population yield only a modest benefit for the stocks of lake trout, whereas increased fishing of lake trout produces substantial potential increases in the yields of Pacific salmon to recreational fisheries. The deepwater or siscowet morphotype of lake trout has become very abundant. Although it plays a major role in the structure of the food web it offers little potential for the restoration of a valuable commercial or recreational fishery

Fleet dynamics of the commercial lake trout fishery in Michigan waters of Lake Superior during 1929-1961

USGS Publications Warehouse

Wilberg, Michael J.; Bronte, Charles R.; Hansen, Michael J.

2004-01-01

Understanding fishing fleet dynamics is important when using fishery dependent data to infer the status of fish stocks. We analyzed data from mandatory catch reports from the commercial lake trout (Salvelinus namaycush) fishery in Michigan waters of Lake Superior during 1929-1961, a period when lake trout populations collapsed through the combined effects of overfishing and sea lamprey (Petromyzon marinus) predation. The number of full-time fishermen increased during 1933-1943 and then decreased during 1943-1957. Addition of new fishermen was related to past yield, market prices, World War II draft exemptions, and lost fishing opportunities in Lake Huron and Lake Michigan. Loss of existing fishermen was related to declining lake trout density. Large mesh (a?Y 114-mm stretch-measure) gill net effort increased during 1929-1951 because fishermen fished more net inshore as lake trout density declined, even though catch per effort (CPE) was often higher in deeper waters. The most common gill net mesh size increased from 114-mm to 120-mm stretch-measure during 1929-1957, as lake trout growth increased. More effort was fished inshore than offshore and the amount of inshore effort was less variable over time than offshore effort. Relatively stable yield was maintained by increasing gill net effort and by moving some effort to better grounds. Because fishing-up caused yield and CPE to remain high despite declining lake trout abundance, caution must be used when basing goals for lake trout restoration on historical fishery indices.

Status and trends in the fish community of Lake Superior, 2012

USGS Publications Warehouse

Gorman, Owen T.; Evrard, Lori M.; Cholwek, Gary A.; Vinson, Mark

2012-01-01

Due to ship mechanical failures, nearshore sampling was delayed from mid-May to mid-June to mid-June to late August. The shift to summer sampling when the lake was stratified may have affected our estimates, thus our estimates of status and trends for the nearshore fish community in 2012 are tentative, pending results of future surveys. However, the results of the 2012 survey are comparable with those during 2009 and 2010 when lake-wide fish biomass declined to < 1.40 kg/ha. Declines in prey fish biomass since the late 1990s can be attributed to a combination of increased predation by recovered lake trout populations and infrequent and weak recruitment by the principal prey fishes, cisco and bloater. In turn declines in lake trout biomass since the mid-2000s are likely linked to declines in prey fish biomass. If lean and siscowet lake trout populations in nearshore waters continue to remain at current levels, predation mortality will likely maintain the relatively low prey fish biomass observed in recent years. Alternatively, if lake trout populations show a substantial decline in abundance in upcoming years, prey fish populations may rebound in a fashion reminiscent to what occurred in the late 1970s to mid-1980s. However, this scenario depends on substantial increases in harvest of lake trout, which seems unlikely given that levels of lake trout harvest have been flat or declining in many regions of Lake Superior since 2000.

Decline of shortjaw cisco in Lake Superior: the role of overfishing and risk of extinction

USGS Publications Warehouse

Bronte, Charles R.; Hoff, Michael H.; Gorman, Owen T.; Thogmartin, Wayne E.; Schneeberger, Philip J.; Todd, Thomas N.

2010-01-01

Recent reviews have further documented the decline of the shortjaw cisco Coregonus zenithicus in Lake Superior. This fish was the most abundant deepwater cisco species in Lake Superior in the early 1920s but presently makes up less than 1% of all deepwater ciscoes (i.e., including shortjaw cisco, bloater C. hoyi, and kiyi C. kiyi) captured in biological surveys. Directed overfishing of deepwater cisco species during the 1930s and again during the mid-1960s and 1970s has been suggested as the cause of the shortjaw cisco's demise. In this paper, we re-examined the overfishing hypothesis by using historical and recent survey data to estimate the proportion of the historical commercial fishery landings that comprised shortjaw ciscoes. We developed time series of estimated harvest and relative abundance for all statistical districts in Michigan waters of Lake Superior during 1929–1996, for which aggregate catch and effort data were available but not previously examined. The spatial distribution of the fishery and the relationships of catch to fishing effort were examined for evidence of overfishing. Our analysis suggested that directed overfishing was probably not the cause of shortjaw cisco demise, as this species appeared to be declining in all statistical districts regardless of the intensity of the fishery. A count-based population viability analysis indicated that quasi-extinction of the shortjaw cisco is highly probable in the near future. We propose an alternative hypothesis based on the decline of Lake Superior's keystone predator, the lake trout Salvelinus namaycush, which resulted in an expansion of the population of its principal prey, the cisco C. artedi, due to release from predation pressure. Competitive or predation interactions between the cisco and shortjaw cisco may be more likely explanations for the demise of the latter species.

A Review of Selected Ecosystem Services Supplied by Coastal Wetlands of the Laurentian Great Lakes

EPA Science Inventory

Significant ecosystem services derive from the coastal wetlands of the Laurentian Great Lakes even though they have undergone substantial declines since European settlement. Basin-wide, two-thirds of the original coastal wetlands have been lost, and the remaining 126,000 ha of US...

LANDSCAPE-SCALE MONITORING OF AN OPPORTUNIST: PHRAGMITES AUSTRALIS (CAV) STEUDEL IN GREAT LAKES COASTAL WETLANDS

EPA Science Inventory

Coastal wetlands of the Laurentian Great Lakes (LGL) are among the most fragmented ecosystems in the world, with a long history of human-induced disturbances, primarily as a result of agricultural conversions and hydrologic changes. A substantial number of remnant LGL coastal wet...

Climate Factors Contributing to Streamflow Inputs and Extreme Water-level Deviations from Long-term Averages for Lakes Superior and Michigan-Huron

NASA Astrophysics Data System (ADS)

Anderson, M. T.; Stamm, J. F.

2014-12-01

The Great Lakes are a highly valued freshwater resource of the United States and Canada. The Lakes are the focus of a science-based restoration program, known as the Great Lakes Restoration Initiative (GLRI). Physical and chemical factors, such as inflows and nutrient loads to the Great Lakes can affect ecosystem function, contribute to the spread of invasive species and increase the occurrence of harmful algal blooms. Since about 1999, water levels in Lakes Superior and Michigan-Huron have been at or below the long-term average (1918 to present). Analyses of streamflow trends for the period 1960 to 2012 in watersheds draining into Lakes Superior and Michigan-Huron showed a long-term decline in average inflows, which helps to explain the persistently below-average lake levels. Recent climatic conditions of October 2013 to August 2014 have contributed to a rapid rise in lake levels, most notably in Lake Superior. Lake Superior recently reached an elevation of 602.56 feet above sea level in August 2014, which is the highest level in 17 years. Coincident with this recovery was the development of a large algal bloom in Lake Erie in August of 2014 that shut down the Toledo, Ohio municipal water supply. These anomalous, extreme deviations from long-term average lake levels will be examined to better understand the forcing factors that contributed to changes in inflow volumes and lake-levels. Particular focus will be given to the climatology of years when changes in lake levels are most pronounced, such as; the measured lake-level declines during 1964-1965 and 1998-2000; and lake-level rises during 1973-1974, 1987-1989, and 2013-2014. The climatology of years with periods of algal blooms will also be examined such as, 2003, 2008, 2011 and 2014.

A new look at the Lake Superior biomass size spectrum

USGS Publications Warehouse

Yurista, Peder M.; Yule, Daniel L.; Balge, Matt; VanAlstine, Jon D.; Thompson, Jo A.; Gamble, Allison E.; Hrabik, Thomas R.; Kelly, John R.; Stockwell, Jason D.; Vinson, Mark

2014-01-01

We synthesized data from multiple sampling programs and years to describe the Lake Superior pelagic biomass size structure. Data consisted of Coulter counts for phytoplankton, optical plankton counts for zooplankton, and acoustic surveys for pelagic prey fish. The size spectrum was stable across two time periods separated by 5 years. The primary scaling or overall slope of the normalized biomass size spectra for the combined years was −1.113, consistent with a previous estimate for Lake Superior (−1.10). Periodic dome structures within the overall biomass size structure were fit to polynomial regressions based on the observed sub-domes within the classical taxonomic positions (algae, zooplankton, and fish). This interpretation of periodic dome delineation was aligned more closely with predator–prey size relationships that exist within the zooplankton (herbivorous, predacious) and fish (planktivorous, piscivorous) taxonomic positions. Domes were spaced approximately every 3.78 log10 units along the axis and with a decreasing peak magnitude of −4.1 log10 units. The relative position of the algal and herbivorous zooplankton domes predicted well the subsequent biomass domes for larger predatory zooplankton and planktivorous prey fish.

FOOD WEB STRUCTURE AS A POTENTIAL INDICATOR OF NUTRIENT ENRICHMENT IN GREAT LAKES COASTAL WETLANDS

EPA Science Inventory

Analyses of the food webs of Great Lakes coastal wetlands verify the role of algae as an energetic foundation, and also suggest that fundamental changes occur in response to both natural and anthropogenic influences. We analyzed coastal wetlands with a range of nutrient concentra...

77 FR 45490 - Safety Zone, Barrel Recovery, Lake Superior; Duluth, MN

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-01

... suspected to contain munitions waste materials which were dumped in the 1960's in a portion of Lake Superior... recreational vessels and marine traffic from any unknown hazards as well as provide a safe work zone for... Waterways Management, U.S. Coast Guard Marine Safety Unit Duluth; telephone number (218) 720- 5286...

Wisconsin's Lake Superior Basin Water Quality Study. Technical Report No. 1.

ERIC Educational Resources Information Center

Dickas, Albert B., Ed.

This hydrologic study focuses on Wisconsin's Lake Superior Basin. Water is the most important natural resource in this area which includes Douglass, Bayfield, Ashland, and Iron counties. This study was undertaken to determine the character of this hydrologic base and to determine the effects and extent of man-influenced disturbances. It includes…

Successional change in the Lake Superior fish community: population trends in ciscoes, rainbow smelt, and lake trout, 1958-2008

USGS Publications Warehouse

Gorman, Owen T.

2012-01-01

The Lake Superior fish community underwent massive changes in the second half of the 20th century. Those changes are largely reflected in changes in abundance of the adults of principal prey species, the ciscoes (Coregonus spp.), the invasive rainbow smelt (Osmerus mordax), and the principal predator, lake trout (Salvelinus namaycush). To better understand changes in species abundances, a comprehensive series of gillnet and bottom trawl data collected from 1958 to 2008 were examined. In the late 1950s/early 1960s, smelt abundance was at its maximum, wild lake trout was at its minimum, and an abundance of hatchery lake trout was increasing rapidly. The bloater (Coregonus hoyi) was the prevalent cisco in the lake; abundance was more than 300% greater than the next most abundant cisco, shortjaw cisco (C. zenithicus), followed by kiyi (C. kiyi) and lake cisco (C. artedi). By the mid-1960s, abundance of hatchery lake trout was nearing maximum, smelt abundance was beginning to decline, and abundances of all ciscoes declined, but especially that of shortjaw cisco and kiyi. By the late 1970s, recovery of wild lake trout stocks was well underway and abundances of hatchery lake trout and smelt were declining and the ciscoes were reaching their nadir. During 1980–1990, the fish community underwent a dramatic shift in organization and structure. The rapid increase in abundance of wild lake trout, concurrent with a rapid decline in hatchery lake trout, signaled the impending recovery. Rainbow smelt abundance dropped precipitously and within four years, lake cisco and bloater populations rebounded on the heels of a series of strong recruitment events. Kiyi populations showed signs of recovery by 1989, and shortjaw by 2000, though well below historic maximum abundances. High abundance of adult smelt prior to 1980 appears to be the only factor linked to recruitment failure in the ciscoes. Life history traits of the cisco species were examined to better understand their different

HYDROGEOMORPHIC INFLUENCES ON MACROPHYTES AS HABITAT IN GREAT LAKES WETLANDS

EPA Science Inventory

We used rapid survey techniques to map saubmergerd, floating and emergent vegetation in 10 coastal wetlands of Lake Superior. Density and structure of plant beds in "bay," "main channel," and "side channel" areas was evaluated from cover indices and presence/dominance by growth f...

Microplastic Abundance and Composition in Western Lake Superior As Determined via Microscopy, Pyr-GC/MS, and FTIR.

PubMed

Hendrickson, Erik; Minor, Elizabeth C; Schreiner, Kathryn

2018-02-20

While plastic pollution in marine and freshwater systems is an active area of research, there is not yet an in-depth understanding of the distributions, chemical compositions, and fates of plastics in aquatic environments. In this study, the magnitude, distribution, and common polymers of microplastic pollution in surface waters in western Lake Superior are determined. Analytical methodology, including estimates of ambient contamination during sample collection and processing, are described and employed. Microscopy, pyrolysis-gas chromatography/mass spectrometry (Pyr-GC/MS), and Fourier transform infrared spectroscopy (FTIR) were used to quantify and identify microplastic particles. In surface waters, fibers were the most frequently observed morphology, and, based upon PyGC/MS analysis,  polyvinyl chloride was the most frequently observed polymer, followed by polypropylene and polyethylene. The most common polymer identified by FTIR was polyethylene. Despite the low human population in Lake Superior's watershed, microplastic particles (particularly fibers, fragments, and films) were identified in western-lake surface waters at levels comparable to average values reported in studies within Lake Michigan, the North Atlantic Ocean, and the South Pacific Ocean. This study provides insight into the magnitude of microplastic pollution in western Lake Superior, and describes in detail methodology to improve future microplastics studies in aquatic systems.

Cross shore transport by wind-driven turbidity plumes in western Lake Superior*

EPA Science Inventory

Turbidity plumes frequently occur in the western arm of Lake Superior and may represent a significant cross shelf transport mechanism for sediment, nutrient and biota. We characterize a plume that formed in late April 2016 using observations from in situ sensors and remote sensin...

New Records and Range Extensions for Several Chironomid Genera from Lake Superior

EPA Science Inventory

Five genera of chironomids have been reported for the first time in Lake Superior. Chironomids are small flying insects with a sediment-dwelling aquatic larval stage. The chironomids were collected by scientists at the Mid-Continent Ecology Division as part of a research program ...

Multi-Objective Lake Superior Regulation

NASA Astrophysics Data System (ADS)

Asadzadeh, M.; Razavi, S.; Tolson, B.

2011-12-01

At the direction of the International Joint Commission (IJC) the International Upper Great Lakes Study (IUGLS) Board is investigating possible changes to the present method of regulating the outflows of Lake Superior (SUP) to better meet the contemporary needs of the stakeholders. In this study, a new plan in the form of a rule curve that is directly interpretable for regulation of SUP is proposed. The proposed rule curve has 18 parameters that should be optimized. The IUGLS Board is also interested in a regulation strategy that considers potential effects of climate uncertainty. Therefore, the quality of the rule curve is assessed simultaneously for multiple supply sequences that represent various future climate scenarios. The rule curve parameters are obtained by solving a computationally intensive bi-objective simulation-optimization problem that maximizes the total increase in navigation and hydropower benefits of the new regulation plan and minimizes the sum of all normalized constraint violations. The objective and constraint values are obtained from a Microsoft Excel based Shared Vision Model (SVM) that compares any new SUP regulation plan with the current regulation policy. The underlying optimization problem is solved by a recently developed, highly efficient multi-objective optimization algorithm called Pareto Archived Dynamically Dimensioned Search (PA-DDS). To further improve the computational efficiency of the simulation-optimization problem, the model pre-emption strategy is used in a novel way to avoid the complete evaluation of regulation plans with low quality in both objectives. Results show that the generated rule curve is robust and typically more reliable when facing unpredictable climate conditions compared to other SUP regulation plans.

Changes in a population of exotic rainbow smelt in Lake Superior: Boom to bust, 1974-2005

USGS Publications Warehouse

Gorman, O.T.

2007-01-01

Changes in a population of rainbow smelt (Osmerus mordax) in the Apostle Islands region of Lake Superior were chronicled over a 32-yr time series, 1974–2005. At the beginning of the time series, rainbow smelt was the predominant prey species, abundance of lake herring (Coregonis artedi) was very low, and the dominant predator was stocked lake trout (Salvelinus namaycush). Following a period of successful lake trout stocking in the 1970s, the rainbow smelt population declined sharply in 1980, largely through mortality of adult fish and subsequent poor recruitment. In the succeeding 4 years, rainbow smelt populations reached historic low levels, resulting in reduced food resources for both wild and stocked lake trout. During 1985–1990 lake herring stocks began a spectacular recovery following the appearance of a very strong 1984 year class and subsequent 1988, 1989, and 1990 year classes. Rainbow smelt benefited from the high abundance of young lake herring as an alternate prey source for lake trout and showed a partial recovery in the late 1980s. However, a growing lake trout population coupled with an 8-yr period of low herring reproduction after 1990 resulted in a diminished rainbow smelt population dominated by age-1 and 2 fish and showing a pattern of alternating recruitment attributed to cannibalism. Low productivity of rainbow smelt and intermittent production of herring over the past decade has left lake trout populations with a diminished prey base. Although lake trout recovery benefited from the presence of rainbow smelt as a prey resource, the Lake Superior fish community was fundamentally altered by the introduction of rainbow smelt.

Distribution of fishes in U. S. streams tributary to Lake Superior

USGS Publications Warehouse

Moore, Harry H.; Braem, Robert A.

1965-01-01

Experimental sea lamprey control by the Bureau of Commercial Fisheries on Lake Superior streams provided many new distributional records of the fish fauna. Seventy-one species were recorded from 175 streams. Specimens were collected at the electromechanical barriers, with electric shockers, with fyke nets, and during chemical treatment of streams. Maps showing stream records of each species are presented.

Geographic, Anthropogenic and Habitat Influences on Great Lakes Coastal Wetland Fish Assemblages

EPA Science Inventory

We analyzed data from coastal wetlands across all five Laurentian Great Lakes to identify patterns in fish assemblages and relationships to local habitat, watershed condition, and regional setting. NMDS ordination of electrofishing catch-per-effort data revealed an overriding ge...

NUTRIENT AND HABITAT INDICATORS FOR CRITERIA DEVELOPMENT IN GREAT LAKES COASTAL WETLANDS

EPA Science Inventory

EPA's Mid-Continent Ecology Division is testing indicators and establishing stressor - response relationships to support development of nutrient and habitat criteria for Great Lakes coastal wetlands. Our focus is on water quality changes, food web shifts, and vegetation loss as ...

WETLAND MORPHOLOGIC AND BIOGEOGRAPHIC INFLUENCES ON ALGAL RESPONSES TO NUTRIENT LOADING IN GREAT LAKES COASTAL WETLANDS

EPA Science Inventory

We are testing the influence of wetland morphology (protected vs. riverine) and biogeography (upper vs. lower Great Lakes) on algal responses to nutrients in Great Lakes Coastal wetlands. Principal components analysis using nutrient-specific GIS data was used to select sites wit...

Lake Superior Harbors of Refuge at Lutsen and Beaver Bay Cook and Lake Counties Minnesota.

DTIC Science & Technology

1977-12-01

attributed to the daily dumping into Lake Superior of 67,000 tons of taconite tailings by the Reserve Mining Cormpany. Reserve Mining will be totally...Reserve Mining must be given a reasonable period of time within which to change its operation to on-land disposal of taconite tailings. 2.33 While...shoreline, the city came into existence. The Reserve Mining Company began its construction of the taconite processing plant in 1951, and it went into

A GIS APPROACH TO IDENTIFY AND CLASSIFY HYDROGEOMORPHIC TYPES OF COASTAL WETLANDS OF THE GREAT LAKES

EPA Science Inventory

There is a need by Great Lakes managers to have a comprehensive inventory of the coastal wetland resources for monitoring and assessment. An electronic database and geographic information system (GIS) point coverage of coastal wetland locations along the U.S. shoreline have been ...

The relative efficiency of nylon and cotton gill nets for taking lake trout in Lake Superior

USGS Publications Warehouse

Pycha, Richard L.

1962-01-01

The change from cotton to nylon twine for gill nets in 1949–52 resulted in a sharp increase in the efficiency of the most important gear used for taking lake trout in Lake Superior, and, consequently, biased estimates of fishing intensity and abundance severely.From early May to the end of September 1961, short gangs (2000 or 4000 linear feet) of cotton and nylon nets were fished in parallel sets for lake trout. A total of 343,000 feet of gill netting was lifted. Nylon nets were 2.25 times as efficient as cotton nets for taking legal-sized fish and 2.8 times as efficient for undersized lake trout. The average lengths of legal, undersized, and all lake trout taken in nets of the two materials did not differ greatly. The percentage of the catch which was undersized (less than 1.25 lb, dressed weight) was 20.8 in nylon nets and 17.7 in cotton. The relative efficiency of cotton and nylon nets showed no trend during the season. The efficiency ratio determined in this study was closely similar to that obtained by earlier workers.Correction of estimates of fishing intensity and abundance for the greater efficiency of the nylon nets used since 1951 has not been attempted. The drastic decline of the lake trout fishery has forced fishermen to make changes in fishing practices in the past few years that cause new bias of an unknown extent to estimates of fishing intensity.

210Pb, 137Cs and 7Be in the sediments of coastal lakes on the polish coast: Implications for sedimentary processes.

PubMed

Woszczyk, Michał; Poręba, Grzegorz; Malinowski, Łukasz

2017-04-01

In this study we combined radioisotopes ( 210 Pb, 137 Cs and 7 Be) and hydrodynamic modeling to investigate sedimentary processes in three coastal lakes on the Polish Baltic coast. The research aimed at establishing the depth of sediment mixing and its effects on sediment geochemistry as well as showing the relationship between lake water salinity and radionuclide distribution in the sediment cores. We established that the intensity of mixing displayed appreciable variability throughout the lakes and the thickness of sediment mixing layer was between <2 and 22 cm. The mixing was primarily due to wind-induced waves. The vertical mixing was shown to shift sulfidation of the sediments towards deeper layers. We found that the distributions of radioisotopes, 137 Cs in particular, in the sediment cores from coastal lakes were strongly affected by the early diagenetic processes, which caused diffusive migration of radionuclides. The inventories of 210 Pb ex and 137 Cs in the lakes were positively related to salinity. The high inventories of both isotopes (3.2-10.9 kBq ·m -2 for 210 Pb ex and 3.0-6.0 kBq·m -2 for 137 Cs) in coastal lakes were explained by enhanced sedimentation within estuarine mixing zone and delivery of "additional" 210 Pb and 137 Cs to the lakes during saltwater ingressions. The results of this study have implications for the paleolimnology, sedimentology and biogeochemistry of coastal lakes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stimulating a Great Lakes coastal wetland seed bank using portable cofferdams: implications for habitat rehabilitation

USGS Publications Warehouse

Kowalski, K.P.; Wilcox, D.A.; Wiley, M.J.

2009-01-01

Coastal wetland seed banks exposed by low lake levels or through management actions fuel the reestablishment of emergent plant assemblages (i.e., wetland habitat) critical to Great Lakes aquatic biota. This project explored the effectiveness of using portable, water-filled cofferdams as a management tool to promote the natural growth of emergent vegetation from the seed bank in a Lake Erie coastal wetland. A series of dams stretching approximately 450??m was installed temporarily to isolate hydrologically a 10-ha corner of the Crane Creek wetland complex from Lake Erie. The test area was dewatered in 2004 to mimic a low-water year, and vegetation sampling characterized the wetland seed bank response at low, middle, and high elevations in areas open to and protected from bird and mammal herbivory. The nearly two-month drawdown stimulated a rapid seed-bank-driven response by 45 plant taxa. Herbivory had little effect on plant species richness, regardless of the location along an elevation gradient. Inundation contributed to the replacement of immature emergent plant species with submersed aquatic species after the dams failed and were removed prematurely. This study revealed a number of important issues that must be considered for effective long-term implementation of portable cofferdam technology to stimulate wetland seed banks, including duration of dewatering, product size, source of clean water, replacement of damaged dams, and regular maintenance. This technology is a potentially important tool in the arsenal used by resource managers seeking to rehabilitate the functions and values of Great Lakes coastal wetland habitats.

Coastal wetland support of Great Lakes fisheries: progress from concept to quantification.

EPA Science Inventory

Fishery support is recognized as a valuable ecosystem service provided by aquatic systems but is harder to quantify than to describe conceptually. In this paper, we intersect data on fish inhabiting Great Lakes coastal wetlands with information on commercial and recreational har...

Functional values of Great Lakes coastal wetlands: What we know and what we can be working towards

EPA Science Inventory

Water quality improvement, shoreline protection, carbon sequestration, and lake productivity subsidy are among the functional values commonly attributed to Great Lakes coastal wetlands (GLCWs). There is much less information concerning these than there is concerning habitat and f...

Sensitivity of Great Lakes Ice Cover to Air Temperature

NASA Astrophysics Data System (ADS)

Austin, J. A.; Titze, D.

2016-12-01

Ice cover is shown to exhibit a strong linear sensitivity to air temperature. Upwards of 70% of ice cover variability on all of the Great Lakes can be explained in terms of air temperature, alone, and nearly 90% of ice cover variability can be explained in some lakes. Ice cover sensitivity to air temperature is high, and a difference in seasonally-averaged (Dec-May) air temperature on the order of 1°C to 2°C can be the difference between a low-ice year and a moderate- to high- ice year. The total amount of seasonal ice cover is most influenced by air temperatures during the meteorological winter, contemporaneous with the time of ice formation. Air temperature conditions during the pre-winter conditioning period and during the spring melting period were found to have less of an impact on seasonal ice cover. This is likely due to the fact that there is a negative feedback mechanism when heat loss goes toward cooling the lake, but a positive feedback mechanism when heat loss goes toward ice formation. Ice cover sensitivity relationships were compared between shallow coastal regions of the Great Lakes and similarly shallow smaller, inland lakes. It was found that the sensitivity to air temperature is similar between these coastal regions and smaller lakes, but that the absolute amount of ice that forms varies significantly between small lakes and the Great Lakes, and amongst the Great Lakes themselves. The Lake Superior application of the ROMS three-dimensional hydrodynamic numerical model verifies a deterministic linear relationship between air temperature and ice cover, which is also strongest around the period of ice formation. When the Lake Superior bathymetry is experimentally adjusted by a constant vertical multiplier, average lake depth is shown to have a nonlinear relationship with seasonal ice cover, and this nonlinearity may be associated with a nonlinear increase in the lake-wide volume of the surface mixed layer.

Predicting geomorphic stability in low-order streams of the western Lake Superior basin

EPA Science Inventory

Width:depth ratios, entrenchment ratios, gradients, and median substrate particle sizes (D50s) were measured in 32 second and third order stream reaches in the western Lake Superior basin, and stream reaches were assigned a Rosgen geomorphic classification. Over 700 measurements ...

Genetic structure of the benthic amphipod Diporeia (Amphipoda: Pontoporeiidae) and its relationship to abundance in Lake Superior

EPA Science Inventory

The freshwater amphipod Diporeia is a crucial part of the food web in the Laurentian Great Lakes, but has faced serious declines correlated with the invasion of zebra mussels (Dreissena polymorpha), except in Lake Superior, which has seen an increase in Diporeia abundance. Specul...

Wisconsin's Lake Superior Basin Water Quality Study. Supplement. Technical Report No. 2.

ERIC Educational Resources Information Center

Whisnant, David M., Ed.

During the period extending from May 1972 through April 1973, an investigation of the overall water quality conditions of streams flowing into Lake Superior from the entire state of Wisconsin was conducted. The goal of this publication was to provide much needed regional information on water quality, drainage basins, pollution sources and loads,…

A rehabilitation plan for walleye populations and habitats in Lake Superior

USGS Publications Warehouse

Hoff, Michael H.

2003-01-01

The walleye (Stizostedion vitreum vitreum) has been historically important in regional fisheries and fish communities in large bays, estuaries, and rivers of Lake Superior. Significant negative impacts on the species caused by overharvesting, habitat degradation, and pollution during the late 1800s and early 1900s have led to the preparation of a strategic rehabilitation plan. The lakewide goal is to maintain, enhance, and rehabilitate habitat for walleye and to establish self-sustaining populations in areas where walleyes historically lived. Population objectives that support the goal are to increase the abundance of juvenile and adult walleyes in selected areas. Habitat objectives that support the goal include increasing spawning and nursery habitat in four areas: enhancing fish passage, reducing sedimentation, increasing water quality, and reducing contaminants in walleyes. Progress toward achieving the habitat objectives should be measured by documenting increases in spawning and nursery habitats, resolving fish-passage issues, reducing sediments in rivers, and reducing contaminant levels in walleyes. Stocking various life stages of walleye should be considered to rehabilitate certain degraded populations. Total annual mortality of walleye populations should be less than 45% to allow populations to either increase or be maintained at target levels of abundance. Routine assessments should focus on gathering the data necessary to evaluate abundance and mortality and on taking inventories of spawning and nursery habitats. Research should be conducted to understand the specific habitat requirements for Lake Superior walleye populations and the habitat-abundance relationships for populations and for the lake as a whole.

Watershed Influences on Nearshore Waters Across the Entire US Great Lakes Coastal Region

EPA Science Inventory

We have combined three elements of observation to enable a comprehensive characterization of the Great Lakes nearshore that links nearshore conditions with their adjacent coastal watersheds. The three elements are: 1) a shore-parallel, high-resolution survey of the nearshore usin...

REMOTE DETECTION OF INVASSIVE AND OPPORTUNISTIC PLANT SPECIES IN GREAT LAKES COASTAL WETLANDS

EPA Science Inventory

Invasive and opportunistic plant species have been associated with wetland disturbance. Increases in the abundance of plant species such as common reed (Phragmites australis) in coastal Great Lakes wetlands are hypothesized to occur with shifts toward drier hydrologic regimes, fr...

REMOTE DETENTION OF INVASIVE AND OPPORTUNISTIC PLANT SPECIES IN GREAT LAKES COASTAL WETLANDS

EPA Science Inventory

Invasive and opportunistic plant species have been associated with wetland disturbance. Increases in the abundance of plant species such as common reed (Phragmites australis) in coastal Great Lakes wetlands are hypothesized to occur with shifts toward drier hydrologic regimes, fr...

NATURAL AND ANTHROPOGENIC FACTORS INFLUENCING FOOD WEB STRUCTURE IN GREAT LAKES COASTAL WETLANDS

EPA Science Inventory

We are investigating factors governing the biological organization of Great Lakes coastal wetlands. Food web analyses using stable isotope techniques verify the role of algae as an energetic foundation, and also suggest that fundamental changes occur as a result of anthropogenic ...

Environmental Indicators for the Coastal Region of North American Great Lakes: Introduction and Prospectus

EPA Science Inventory

Environmental indicators are benchmarks for the current conditions of the Great Lakes coastal region and provide measurable endpoints to assess the success of future management, conservation, protection, and restoration of this important resource.

EPA’s National Coastal Condition Assessment: Pilot research in Great Lakes connecting channels

EPA Science Inventory

The EPA Office of Water’s 5-year cycles of national surveys of wetlands, lakes, rivers, and coastal areas help satisfy the assessment and antidegradation provisions of the Clean Water Act. Measuring extant conditions precedes measuring change in conditions. Surveys are chal...

Buried soils in a perched dunefield as indicators of late holecene lake-level change in the Lake Superior basin

USGS Publications Warehouse

Anderton, John B.; Loope, Walter L.

1995-01-01

A stratigraphic analysis of buried soils within the Grand Sable Dunes, a dune field perched 90 m above the southern shore of Lake Superior, reveals a history of eolian activity apparently linked with lake-level fluctuations over the last 5500 yr. A relative rise in the water plane of the Nipissing Great Lakes initially destabilized the lakeward bluff face of the Grand Sable plateau between 5400 and 4600 14C yr B.P. This led to the burial of the Sable Creek soil by eolian sediments derived from the bluff face. Subsequent episodes of eolian activity appear to be tied to similar destabilizing events; high lake levels may have initiated at least four and perhaps eleven episodes of dune building as expressed by soil burials within the dunes. Intervening low lake levels probably correlate with soil profile development, which varies from the well-developed Sable Creek Spodosol catena to thin organic layers containing in-place stumps and tree trunks. Paleoecological reconstructions available for the area do not imply enough climatic change to account for the episodic dune activity. Burial of soils by fine-fraction sediments links dune-building episodes with destabilization of the lower lake-facing bluff, which is rich in fines.

Remote Sensing and Underwater Glider Observations of a Springtime Plume in Western Lake Superior

EPA Science Inventory

Plumes are commonly observed in satellite imagery of western Lake Superior following storm events, and represent a significant cross-shelf pathway for sediment and other constituents. However, their subsurface extent is poorly understood. This study reports results from plume ob...

Reassessment of the predatory effects of rainbow smelt on ciscoes in Lake Superior

USGS Publications Warehouse

Myers, Jared T.; Jones, Michael L.; Stockwell, Jason D.; Yule, Daniel L.

2009-01-01

Evidence from small lakes suggests that predation on larval ciscoes Coregonus artedi by nonnative rainbow smelt Osmerus mordax can lead to cisco suppression or extirpation. However, evidence from larger lakes has led to equivocal conclusions. In this study, we examine the potential predation effects of rainbow smelt in two adjacent but contrasting embayments in Lake Superior (Thunder and Black bays, Ontario). During May 2006, we sampled the ichthyoplankton, pelagic fish communities, and diet composition of rainbow smelt in both bays. Using acoustics and midwater trawling, we estimated rainbow smelt densities to be 476 ± 34/ha (mean ± SE) in Thunder Bay and 3,435 ± 460/ha in Black Bay. We used a bioenergetics model to estimate the proportion of cisco larvae consumed by rainbow smelt. Our results suggest that predation by rainbow smelt accounts for 15–52% and 37–100% of the mortality of larval ciscoes in Thunder and Black bays, respectively, depending on the predator feeding rate and the scale of predator–prey overlap. We also examined the sensitivity of past conclusions (based on 1974 field collections) to assumptions of temporal overlap between rainbow smelt and larval ciscoes and estimates of rainbow smelt abundance derived from bottom trawl samples. After adjusting these parameters to reflect current understanding, we found that the previous predation estimates may have been conservative. We conclude that rainbow smelt may have been a more important contributor to the demise and slow recovery of ciscoes in Lake Superior than previously thought.

Empirical evaluation of predator-driven diel vertical migration in Lake Superior

USGS Publications Warehouse

Stockwell, J.D.; Hrabik, T.R.; Jensen, O.P.; Yule, D.L.; Balge, M.

2010-01-01

Recent studies on Lake Superior suggest that diel vertical migration (DVM) of prey (generalized Coregonus spp.) may be influenced by the density of predatory siscowet (Salvelinus namaycush). We empirically evaluated this hypothesis using data from acoustic, midwater trawl, and bottom trawl sampling at eight Lake Superior sites during three seasons in 2005 and a subset of sites in 2006. We expected the larger-bodied cisco (Coregonus artedi) to exhibit a shallower DVM compared with the smaller-bodied kiyi (Coregonus kiyi). Although DVM of kiyi and cisco were consistent with expectations of DVM as a size-dependent, predator-mediated process, we found no relationship between siscowet density and the magnitude of DVM of either coregonid. Cisco appear to have a size refuge from siscowet predation. Kiyi and siscowet co-occur in demersal habitat > 150 m during the day, where visual predation is unlikely, suggesting predator avoidance is not a factor in the daytime distribution of kiyi. Seasonal patterns of kiyi DVM were consistent with reported DVM of their primary prey Mysis relicta. Our results suggest that consideration of nonvisual foraging, rather than lightbased foraging theory (i.e., the antipredation window), is necessary to understand the processes driving DVM in deepwater systems.

Distribution of native mussel (unionidae) assemblages in coastal areas of Lake Erie, Lake St. Clair, and connecting channels, twenty-five years after a dreissenid invasion

USGS Publications Warehouse

Zanatta, David T.; Bossenbroek, Jonathan M.; Burlakova, Lyubov E.; Crail, Todd D.; Szalay, Ferenc de; Griffith, Traci A.; Kapusinski, Douglas; Karatayev, Alexander Y.; Krebs, Robert A.; Meyer, Elizabeth S.; Paterson, Wendy L.; Prescott, Trevor J.; Rowe, Matthew T.; Schloesser, Donald W.; Walsh, Mary C.

2015-01-01

Over the past 25 years, unionid mussels in the Laurentian Great Lakes of North America have been adversely impacted by invasive dreissenid mussels, which directly (e.g., by attachment to unionid shells) and indirectly (e.g., by competing for food) cause mortality. Despite the invasion, unionids have survived in several areas in the presence of dreissenid mussels. We investigated current spatial patterns in these native mussel refuges based on surveys for unionid mussels across 48 sampling locations (141 sites) in 2011 and 2012, and documented species abundance and diversity in coastal areas of lakes St. Clair and Erie. The highest-quality assemblages of native mussels (densities, richness, and diversity) appear to be concentrated in the St. Clair delta, where abundance continues to decline, as well as in in Thompson Bay of Presque Isle in Lake Erie and in just a few coastal wetlands and drowned river-mouths in the western basin of Lake Erie. The discovery of several new refuge areas suggests that unionids have a broader distribution within the region than previously thought.

Spatio-temporal analysis of gyres in oriented lakes on the Arctic Coastal Plain of northern Alaska based on remotely sensed images

USGS Publications Warehouse

Zhan, Shengan; Beck, Richard A.; Hinkel, Kenneth M.; Liu, Hongxing; Jones, Benjamin M.

2014-01-01

The formation of oriented thermokarst lakes on the Arctic Coastal Plain of northern Alaska has been the subject of debate for more than half a century. The striking elongation of the lakes perpendicular to the prevailing wind direction has led to the development of a preferred wind-generated gyre hypothesis, while other hypotheses include a combination of sun angle, topographic aspect, and/or antecedent conditions. A spatio-temporal analysis of oriented thermokarst lake gyres with recent (Landsat 8) and historical (Landsat 4, 5, 7 and ASTER) satellite imagery of the Arctic Coastal Plain of northern Alaska indicates that wind-generated gyres are both frequent and regionally extensive. Gyres are most common in lakes located near the Arctic coast after several days of sustained winds from a single direction, typically the northeast, and decrease in number landward with decreasing wind energy. This analysis indicates that the conditions necessary for the Carson and Hussey (1962) wind-generated gyre for oriented thermokarst lake formation are common temporally and regionally and correspond spatially with the geographic distribution of oriented lakes on the Arctic Coastal Plain. Given an increase in the ice-free season for lakes as well as strengthening of the wind regime, the frequency and distribution of lake gyres may increase. This increase has implications for changes in northern high latitude aquatic ecosystems, particularly if wind-generated gyres promote permafrost degradation and thermokarst lake expansion.

Periphyton accumulation at remote reefs and shoals in Lake Superior

USGS Publications Warehouse

Edsall, Thomas A.; Stoermer, Eugene F.; Kociolek, John P.

1991-01-01

Observations made from a submarine showed that the bed-rock surfaces at water depths of about 5 to 14 m on Stannard Rock and Superior Shoal in Lake Superior were covered with a dense, fleece-like blanket of periphyton. Examination of the periphyton revealed it consisted primarily of structurally complex, diverse, diatom communities, but occasional small thalli of the green algae Cladophora andStigeoclonium were also noted. Extensive windrows of detritus-like material, apparently derived from the local periphyton community, were seen on soft bottoms at depths of about 20 to 60 m near the reefs. Our observations suggested that these periphyton communities may be locally important to the food web at these remote and oligotrophic sites, which are 22 to 77 km from the nearest mainland shore and are surrounded by water at least 140 m deep.

Reconstructing fish movements between coastal wetland and nearshore habitats of the Great Lakes

EPA Science Inventory

The use of resources from multiple habitats has been shown to be important to the production of aquatic consumers. To quantify the support of Great Lakes coastal wetland (WL) and nearshore (NS) habitats to yellow perch, we used otolith microchemistry to trace movements between th...

Predicting geomorphic stability in low-order streams of the western Lake Superior basin - Poster

EPA Science Inventory

Width:depth ratios, entrenchment ratios, gradients, and median substrate particle sizes (D50s) were measured in 32 second- and third-order stream reaches in the western Lake Superior basin in 1997-1998. More than 700 measurements of suspended sediment concentration during snowmel...

Principles in sampling design, lessons, and recommendations from a multi-year, multi-port surveillance program in Lake Superior

EPA Science Inventory

We evaluated a pilot aquatic invasive species (AIS) early detection monitoring program in Lake Superior that was designed to detect newly-introduced fishes. We established survey protocols for three major ports (Duluth-Superior, Sault Ste. Marie, Thunder Bay), and designed an ada...

Climate Change Expands the Spatial Extent and Duration of Preferred Thermal Habitat for Lake Superior Fishes

PubMed Central

Cline, Timothy J.; Bennington, Val; Kitchell, James F.

2013-01-01

Climate change is expected to alter species distributions and habitat suitability across the globe. Understanding these shifting distributions is critical for adaptive resource management. The role of temperature in fish habitat and energetics is well established and can be used to evaluate climate change effects on habitat distributions and food web interactions. Lake Superior water temperatures are rising rapidly in response to climate change and this is likely influencing species distributions and interactions. We use a three-dimensional hydrodynamic model that captures temperature changes in Lake Superior over the last 3 decades to investigate shifts in habitat size and duration of preferred temperatures for four different fishes. We evaluated habitat changes in two native lake trout (Salvelinus namaycush) ecotypes, siscowet and lean lake trout, Chinook salmon (Oncorhynchus tshawytscha), and walleye (Sander vitreus). Between 1979 and 2006, days with available preferred thermal habitat increased at a mean rate of 6, 7, and 5 days per decade for lean lake trout, Chinook salmon, and walleye, respectively. Siscowet lake trout lost 3 days per decade. Consequently, preferred habitat spatial extents increased at a rate of 579, 495 and 419 km2 per year for the lean lake trout, Chinook salmon, and walleye while siscowet lost 161 km2 per year during the modeled period. Habitat increases could lead to increased growth and production for three of the four fishes. Consequently, greater habitat overlap may intensify interguild competition and food web interactions. Loss of cold-water habitat for siscowet, having the coldest thermal preference, could forecast potential changes from continued warming. Additionally, continued warming may render more suitable conditions for some invasive species. PMID:23638023

DEVELOPMENT OF INDICATORS OF EXPOSURE AND RESPONSE TO SEDIMENT AND HABITAT ALTERATION IN LAKE MICHIGAN COASTAL RIVERINE WETLANDS

EPA Science Inventory

Measures are being assessed to quantify the relationship of land-use in upstream watersheds to the habitat and biota in downstream coastal wetlands. Twenty-two sites were randomly drawn from a pool of 125 identified as riverine coastal wetlands along the shore of Lake Michigan. W...

Detection of Viral Hemorrhagic Septicemia Virus by Quantitative Reverse Transcription Polymerase Chain Reaction from Two Fish Species at Two Sites in Lake Superior

USGS Publications Warehouse

Cornwell, Emily R.; Eckerlin, Geofrey E.; Getchell, Rodman G.; Groocock, Geoffrey H.; Thompson, Tarin M.; Batts, William N.; Casey, Rufina N.; Kurath, Gael; Winton, James R.; Bowser, Paul R.; Bain, Mark B.; Casey, James W.

2011-01-01

Viral hemorrhagic septicemia virus (VHSV) was first detected in the Laurentian Great Lakes in 2005 during a mortality event in the Bay of Quinte, Lake Ontario. Subsequent analysis of archived samples determined that the first known isolation of VHSV in the Laurentian Great Lakes was from a muskellunge Esox masquinongy collected in Lake St. Clair in 2003. By the end of 2008, mortality events and viral isolations had occurred in all of the Laurentian Great Lakes except Lake Superior. In 2009, a focused disease surveillance program was designed to determine whether VHSV was also present in Lake Superior. In this survey, 874 fish from 7 sites along the U.S. shoreline of Lake Superior were collected during June 2009. Collections were focused on nearshore species known to be susceptible to VHSV. All fish were dissected individually by using aseptic techniques and were tested for the presence of VHSV genetic material by use of a quantitative reverse transcription (qRT) polymerase chain reaction (PCR) targeting the viral nucleoprotein gene. Seventeen fish from two host species at two different sites tested positive at low levels for VHSV. All attempts to isolate virus in cell culture were unsuccessful. However, the presence of viral RNA was confirmed independently in five fish by using a nested PCR that targeted the glycoprotein (G) gene. Partial G gene sequences obtained from three fish were identical to the corresponding sequence from the original 2003 VHSV isolate (MI03) from muskellunge. These detections represent the earliest evidence for the presence of VHSV in Lake Superior and illustrate the utility of the highly sensitive qRT-PCR assay for disease surveillance in aquatic animals.

Assessment of microcystins in lake water and fish (Mugilidae, Liza sp.) in the largest Spanish coastal lake.

PubMed

Romo, Susana; Fernández, Francisca; Ouahid, Youness; Barón-Sola, Ángel

2012-01-01

Cyanobacteria dominance and cyanotoxin production can become major threats to humans and aquatic life, especially in warm shallow lakes, which are often dominated by cyanobacteria. This study investigates the occurrence and distribution of microcystins (MCYST) in water, cell-bound and in the tissues of the commercial mugilid Liza sp. in the largest, coastal, Spanish Mediterranean lake (Albufera of Valencia). This is the first report concerning microcystin accumulation in tissues of mugilid fish species. Considerable amounts of microcystins were found in the water and seston, which correlated with development of Microcystis aeruginosa populations in the lake. The MCYST concentrations found in Lake Albufera (mean 1.7 and 17 μg/L and maximum 16 and 120 μg/L in water and seston, respectively) exceeded by one to two orders of magnitude the guideline levels proposed by the World Health Organization and were higher than that reported in other lakes of the Mediterranean zone. The presence of MCYST was found in all the fishes studied and accumulated differently among tissues of the commercial species Liza sp. Toxin accumulation in fish tissues showed that although the target organ for MCYST was the liver, high concentrations of microcystins were also found in other analysed tissues (liver>intestine>gills>muscle). Human tolerable daily intake for microcystins is assessed relative to the WHO guidelines, and potential toxicological risks for humans, wildlife and related ecosystems of the lake are discussed.

Shifting balance of thermokarst lake ice regimes across the Arctic Coastal Plain of northern Alaska

USGS Publications Warehouse

Arp, Christopher D.; Jones, Benjamin M.; Lu, Zong; Whitman, Matthew S.

2012-01-01

The balance of thermokarst lakes with bedfast- and floating-ice regimes across Arctic lowlands regulates heat storage, permafrost thaw, winter-water supply, and over-wintering aquatic habitat. Using a time-series of late-winter synthetic aperture radar (SAR) imagery to distinguish lake ice regimes in two regions of the Arctic Coastal Plain of northern Alaska from 2003–2011, we found that 18% of the lakes had intermittent ice regimes, varying between bedfast-ice and floating-ice conditions. Comparing this dataset with a radar-based lake classification from 1980 showed that 16% of the bedfast-ice lakes had shifted to floating-ice regimes. A simulated lake ice thinning trend of 1.5 cm/yr since 1978 is believed to be the primary factor driving this form of lake change. The most profound impacts of this regime shift in Arctic lakes may be an increase in the landscape-scale thermal offset created by additional lake heat storage and its role in talik development in otherwise continuous permafrost as well as increases in over-winter aquatic habitat and winter-water supply.

Production of sea lamprey larvae from nests in two Lake Superior streams

USGS Publications Warehouse

Manion, Patrick J.

1968-01-01

The life history of the landlocked sea lamprey, Petromyzon marinus, has been described by several authors, the two most recent of which are Applegate and Wigley. The only information on the production of larvae from nests of the sea lamprey was reported by Applegate, who counted the larvae from three nests in the Ocqueoc River, a tributary of Lake Huron. The present report presents data on the hatching success of sea lamprey larvae from 19 nests in two small tributaries of southern Lake Superior and indicates greater production per nest than that recorded by Applegate. Studies were conducted by personnel of the U.S. Bureau of Commercial Fisheries on the Little Garlic River, Marquette County, Michigan, and on the Traverse River, Keweenaw County, Michigan.

THE INFLUENCE OF FOREST FRAGMENTATION AND OTHER ENVIRONMENTAL FACTORS ON LAKE SUPERIOR STREAM FISH ASSEMBLAGE

EPA Science Inventory

As part of a comparative watershed project investigating land cover/land use disturbance gradients for streams in the western Lake Superior region, we wanted to determine the relative influence of hydrogeomorphic region, forest fragmentation, watershed storage, and in-stream habi...

THE INFLUENCE OF FOREST FRAGMENTATION AND OTHER ENVIRONMENTAL FACTORS ON LAKE SUPERIOR STREAM FISH ASSEMBLAGES

EPA Science Inventory

As part of a comparative watershed project investigation land cover/land use disturbance gradients for streams in the western Lake Superior region, we wanted to determine the relative influence of hydrogeomorphic region, forest fragmentation, watershed storage and in-stream habit...

The geographical conditions of intensity of salty waters intrusions to coastal lakes on Polish Southern Baltic coast

NASA Astrophysics Data System (ADS)

Cieslinski, R.

2009-04-01

Lakes situated on the coast of the southern Baltic function in different conditions than those in which typically inland reservoirs occur. They are situated in the contact zone of two environments: land and sea. These reservoirs together with their direct catchments form specific hydrographic arrangement, in which the course of physical, chemical and biological processes depends on the fact which of these two environments exerts a stronger influence at a given moment. This is important as the lakes situated in the shore zone of the southern Baltic are not exposed to phenomena caused by constant tides, as it is the case in open seas (Ataie-Ashtiani et al., 1999), but only to extreme hydrometeorological conditions, which lead to the formation of the phenomenon of intrusions of sea waters and of damming the free outflow of potamic waters (Demirel, 2004; Cieśliński, Drwal, 2005). What should also be remembered are the local hydrographic, hydrological and morphometric conditions. As a result of intrusions, in the waters of coastal lakes, apart from inland waters there are also waters of sea origin. The proportions of these genetically distinct waters are variable and differ in individual lakes (Grassi, Netti, 2000; Drwal, Cieśliński, 2007). Despite the difference in the causal factor triggering the phenomenon of salt water intrusions, the effect is usually the same as that observed, for instance, in lakes and lagoons of seas with tides (Ishitobi et al., 1999; De Louw, Oude Essink, 2001) and poorly flushed lagoon (Hsing-Juh et al., 2006) or estuaries (Uncles et al., 2002), though the scale of qualitative changes is greater in the case of open seas than in half-closed and closed seas. The status of the research carried out so far enables proposing a hypothesis that chlorides concentrations, as the best indicators for establishing the occurrence of the phenomenon of intrusions, depend not only on the meteorological factor but in some of the lakes on various

Does Terrestrial Carbon Explain Lake Superior Model-Data pCO2 Discrepancy?

NASA Astrophysics Data System (ADS)

Bennington, V.; McKinley, G. A.; Atilla, N.; Kimura, N.; Urban, N.; Wu, C.; Desai, A.

2008-12-01

As part of the CyCLeS project, a three-dimensional hydrodynamic model (MITgcm) was coupled to a medium- complexity ecosystem model and applied to Lake Superior in order to constrain the seasonal cycle of lake pCO2 and air-lake fluxes of CO2. Previous estimates of CO2 emissions from the lake, while very large, were based on field measurements of very limited spatial and temporal extent. The model allows a more realistic extrapolation from the limited data by incorporation of lake-wide circulation and food web dynamics. A large discrepancy (200 uatm) between observations and model-predicted pCO2 during spring suggests a significant input of terrestrial carbon into the lake. The physical model has 10-km horizontal resolution with 29 vertical layers, ten of which are in the top 50 m of the water column. The model is forced by interpolated meteorological data obtained from land-based weather stations, buoys, and other measurements. Modeled surface temperatures compare well to satellite- based surface water temperature images derived from NOAA AVHRR (Advanced Very High Resolution Radiometer), though there are regional patterns of bias that suggest errors in the heat flux forcing. Growth of two classes of phytoplankton is modeled as a function of temperature, light, and nutrients. One grazer preys upon all phytoplankton. The cycles of carbon and phosphorous are explicitly modeled throughout the water column. The model is able to replicate the observed seasonal cycle of lake chlorophyll and the deep chlorophyll maximum. The model is unable to capture the magnitude of observed CO2 super-saturation during spring without considering external carbon inputs to the lake. Simple box model results suggest that the estimated pool of terrestrial carbon in the lake (17 TgC) must remineralize with a timescale of months during spring in order to account for the model/data pCO2 difference. River inputs and enhanced remineralization in spring due to photo-oxidation are other mechanisms

Burrowing mayflies as indicators of ecosystem health: Status of populations in two western Lake Superior embayments

USGS Publications Warehouse

Edsall, Thomas A.; Gorman, Owen T.; Evrard, Lori M.

2004-01-01

The U.S. Environmental Protection Agency and Environment Canada are supporting the development of indicators of ecosystem health that can be used to report on progress in restoring and maintaining the Great Lakes ecosystem, as called for in the Great Lakes Water Quality Agreement between the United States and Canada. One indicator under development for Great Lakes mesotrophic environments is based on burrowing mayflies (Hexagenia: Ephemeroptera: Ephemeridae). In this paper, we report the results of a benthic survey in spring 2002 to determine the status of nymphal populations of Hexagenia in two western Lake Superior embayments, the St. Louis River estuary, an area with significant water-use impairments, and Chequamegon Bay, an area with no known water-use impairments. Ponar grab samples collected throughout these embayments showed nymphs were generally abundant in finely particulate, cohesive substrate (clay or mixtures of clay and sand) in both embayments. However, in the St. Louis River estuary nymphs were absent in those preferred substrates at 11 stations in the eastern portion of St. Louis Bay and the adjoining northwestern portion of the Duluth-Superior Harbor, where the sediments were variously contaminated with visible amounts of taconite pellets, paint chips, oil, or combusted coal waste (clinkers). Our results suggest that human activities have rendered those portions of the St. Louis River estuary unsuitable for habitation by Hexagenia nymphs and we recommend that trend monitoring of the nymphal population there be conducted to permit reporting on progress in restoring and maintaining the health and integrity of this Great Lakes ecosystem embayment, consistent with the intent of the Great Lakes Water Quality Agreement.

Effectiveness of a refuge for lake trout in western Lake Superior I: Empirical analysis of past performance

USGS Publications Warehouse

Johnson, Melissa J.; Hansen, Michael J.; Seider, Michael J.

2015-01-01

The Gull Island Shoal Refuge was created in 1976 in response to overfishing of the Lake Trout Salvelinus namaycush population in the Apostle Islands region of western Lake Superior. Our objective was to evaluate effectiveness of the refuge by determining whether Lake Trout abundance, growth, maturity, and mortality differed inside and outside the refuge. We compared abundance of wild and stocked fish captured inside and outside the refuge during spring large-mesh gill-net and summer graded-mesh gill-net surveys. We compared growth and mortality during four periods corresponding to four generations of wild Lake Trout, including the last generation that hatched before the refuge was instituted (sampled in 1981–1984) and three generations that were protected by the refuge (sampled in 1985–1992, 1993–2000, and 2001–2010). Maturity of wild fish inside and outside the refuge was compared only for the latter period (2001–2010) because maturity was not assessed earlier. After the refuge was created, wild Lake Trout abundance increased and stocked Lake Trout abundance decreased. Wild adults and juveniles were more abundant inside than outside the refuge, and stocked adults were less abundant inside than outside the refuge. Growth of wild fish did not differ inside versus outside the refuge before 2001, but wild fish grew faster to a shorter asymptotic length inside than outside the refuge during 2001–2010. Wild fish matured at a similar length but an older age inside than outside the refuge during 2001–2010. Survival of wild fish did not differ inside versus outside the refuge before 1993, but mortality was lower inside than outside the refuge during later periods (1993–2000 and 2001–2010). We conclude that the Gull Island Shoal Refuge enhanced the population growth of wild Lake Trout in the Apostle Islands region and should be retained in the future to sustain conditions that favor population growth.

Assessing sediment quality in the Great Lakes Connecting Channels using National Coastal Condition Assessment protocol

EPA Science Inventory

The EPA Office of Water’s National Coastal Condition Assessment (NCCA) helps satisfy the assessment and antidegradation provisions of the Clean Water Actby estimating water, sediment, and benthic quality conditions in the Great Lakes nearshore on a five-year cycle starting ...

Radiocarbon and stable-isotope geochemistry of organic and inorganic carbon in Lake Superior

NASA Astrophysics Data System (ADS)

Zigah, Prosper K.; Minor, Elizabeth C.; Werne, Josef P.

2012-03-01

We present a lake-wide investigation of Lake Superior carbon and organic matter biogeochemistry using radiocarbon, stable isotope, and carbon concentrations. Dissolved inorganic carbon (DIC) abundance in the lake was 121-122 Tg C, with offshore concentration andδ13C values being laterally homogenous and tightly coupled to the physical and thermal regime and biochemical processes. Offshore Δ14C of DIC (50-65‰) exhibited lateral homogeneity and was more 14C enriched than co-occurring atmospheric CO2 (˜38‰); nearshore Δ14C of DIC (36-38‰) was similar to atmospheric CO2. Dissolved organic carbon (DOC) abundance was 14.2-16.4 Tg C. DOC's concentration and δ13C were homogenous in June (mixed lake), but varied laterally during August (stratification) possibly due to spatial differences in lake productivity. Throughout sampling, DOC had modern radiocarbon values (14-58‰) indicating a semilabile nature with a turnover time of ≤60 years. Lake particulate organic carbon (POC, 0.9-1.3 Tg C) was consistently 13C depleted relative to DOC. The δ15N of epilimnetic particulate organic nitrogen shifted to more negative values during stratification possibly indicating greater use of nitrate (rather than ammonium) by phytoplankton in August. POC's radiocarbon was spatially heterogeneous (Δ14C range: 58‰ to -303‰), and generally 14C depleted relative to DOC and DIC. POC 14C depletion could not be accounted for by black carbon in the lake but, because of its spatial and temporal distribution, is attributed to sediment resuspension. The presence of old POC within the epilimnion of the open lake indicates possible benthic-pelagic coupling in the lake's organic carbon cycle; the ultimate fate of this old POC bears further investigation.

Lake-level variability and water availability in the Great Lakes

USGS Publications Warehouse

Wilcox, Douglas A.; Thompson, Todd A.; Booth, Robert K.; Nicholas, J.R.

2007-01-01

In this report, we present recorded and reconstructed (pre-historical) changes in water levels in the Great Lakes, relate them to climate changes of the past, and highlight major water-availability implications for storage, coastal ecosystems, and human activities. 'Water availability,' as conceptualized herein, includes a recognition that water must be available for human and natural uses, but the balancing of how much should be set aside for which use is not discussed. The Great Lakes Basin covers a large area of North America. The lakes capture and store great volumes of water that are critical in maintaining human activities and natural ecosystems. Water enters the lakes mostly in the form of precipitation and streamflow. Although flow through the connecting channels is a primary output from the lakes, evaporation is also a major output. Water levels in the lakes vary naturally on timescales that range from hours to millennia; storage of water in the lakes changes at the seasonal to millennial scales in response to lake-level changes. Short-term changes result from storm surges and seiches and do not affect storage. Seasonal changes are driven by differences in net basin supply during the year related to snowmelt, precipitation, and evaporation. Annual to millennial changes are driven by subtle to major climatic changes affecting both precipitation (and resulting streamflow) and evaporation. Rebounding of the Earth's surface in response to loss of the weight of melted glaciers has differentially affected water levels. Rebound rates have not been uniform across the basin, causing the hydrologic outlet of each lake to rise in elevation more rapidly than some parts of the coastlines. The result is a long-term change in lake level with respect to shoreline features that differs from site to site. The reconstructed water-level history of Lake Michigan-Huron over the past 4,700 years shows three major high phases from 2,300 to 3,300, 1,100 to 2,000, and 0 to 800

Conservation genetics of Lake Superior brook trout: Issues, questions, and directions

USGS Publications Warehouse

Wilson, C.C.; Stott, W.; Miller, L.; D'Amelio, S.; Jennings, Martin J.; Cooper, A.M.

2008-01-01

Parallel efforts by several genetic research groups have tackled common themes relating to management concerns about and recent rehabilitation opportunities for coaster brook trout Salvelinus fontinalis in Lake Superior. The questions that have been addressed include the evolutionary and genetic status of coaster brook trout, the degree of relatedness among coaster populations and their relationship to riverine tributary brook trout populations, and the role and effectiveness of stocking in maintaining and restoring coasters to Lake Superior. Congruent genetic results indicate that coasters are an ecotype (life history variant) rather than an evolutionarily significant unit or genetically distinct strain. Regional structure exists among brook trout stocks, coasters being produced from local populations. Introgression of hatchery genes into wild populations appears to vary regionally and may relate to local population size, habitat integrity, and anthropogenic pressures. Tracking the genetic diversity and integrity associated with captive breeding programs is helping to ensure that the fish used for stocking are representative of their source populations and appropriate for rehabilitation efforts. Comparative analysis of shared samples among collaborating laboratories is enabling standardization of genotype scoring and interpretation as well as the development of a common toolkit for assessing genetic structure and diversity. Incorporation of genetic data into rehabilitation projects will facilitate monitoring efforts and subsequent adaptive management. Together, these multifaceted efforts provide comprehensive insights into the biology of coaster brook trout and enhance restoration options. ?? Copyright by the American Fisheries Society 2008.

Assessing ecological conditions in the Great Lakes Connecting Channels using National Coastal Condition Assessment protocol

EPA Science Inventory

The EPA Office of Water’s National Coastal Condition Assessment (NCCA) helps satisfy the assessment and antidegradation provisions of the Clean Water Act by estimating water, sediment, and benthic quality conditions in the Great Lakes nearshore on a five-year cycle starting...

Techniques for restoration of disturbed coastal wetlands of the Great Lakes

USGS Publications Warehouse

Wilcox, Douglas A.; Whillans, Thomas H.

1999-01-01

A long history of human-induced degradation of Great Lakes wetlands has made restoration a necessity, but the practice of wetland restoration is relatively new, especially in large lake systems. Therefore, we compiled tested methods and developed additional potential methods based on scientific understanding of Great Lakes wetland ecosytems to providc an overview of approaches for restoration. We addressed this challenge by focusing on four general fields of science: hydrology, sedimentology, chemistry, and biology. Hydrologic remediation methods include restoring hydrologic connections between diked and hydrologically altered wetlands and the lakes, restoring water tables lowered by ditching, and restoring natural variation in lake levels of regulated lakes Superior and Ontario. Sedimentological remediation methods include management of sediment input from uplands, removal or proper management of dams on tributary rivers, and restoration of protective barrier beaches and sand spits. Chemical remediation methods include reducing or eliminating inputs of contaminants from point and non-pont sources, natural sediment remediation by biodegradation and chemical degradation, and active sediment remediation by removal or byin situ treatment Biological remediation methods include control of non-target organisms, enhancing populations of target organisms, and enhancing habitat for target organisms. Some of these method were used in three major restoration projects (Metzger Marsh on Lake Erie and Cootes Paradise and Oshawa Second Marsh on Lake Ontario), which are described as case studies to show practical applications of wetland restoration in the Great Lakes. Successful restoration techniques that do not require continued manipulation must be founded in the basic tenets of ecology and should mimic natural processes. Success is demonstrated by the sustainability, productivity, nutrient-retention ability, invasibility, and biotic interactions within a restored wetland.

Current and historical concentrations of poly and perfluorinated compounds in sediments of the northern Great Lakes - Superior, Huron, and Michigan.

PubMed

Codling, Garry; Hosseini, Soheil; Corcoran, Margaret B; Bonina, Solidea; Lin, Tian; Li, An; Sturchio, Neil C; Rockne, Karl J; Ji, Kyunghee; Peng, Hui; Giesy, John P

2018-05-01

Current and historical concentrations of 22 poly- and perfluorinated compounds (PFASs) in sediment collected from Lake Superior and northern Lake Michigan in 2011 and Lake Huron in 2012 are reported. The sampling was performed in two ways, Ponar grabs of surface sediments for current spatial distribution across the lake and dated cores for multi-decadal temporal trends. Mean concentrations of the sum of PFASs (∑PFASs) were 1.5, 4.6 and 3.1 ng g -1 dry mas (dm) in surface sediments for Lakes Superior, Michigan and Huron, respectively. Of the five Laurentian Lakes, the watersheds of Superior and Huron are the less densely populated by humans, and concentrations observed were typically less and from more diffuse sources, due to lesser urbanization and industrialization. However, some regions of greater concentrations were observed and might indicate more local, point sources. In core samples concentrations ranged from lakes with concentrations typically increasing with time. Distributions of PFASs within dated cores largely corresponded with increase in use of PFASs, but with physiochemical characteristics also affecting distribution. Perfluoroalkyl sulfonates (PFSAs) with chain lengths >7 that include perfluoro-n-octane sulfonate (PFOS) bind more strongly to sediment, which resulted in more accurate analyses of temporal trends. Shorter-chain PFASs, such as perfluoro-n-butanoic acid which is the primary replacement for C8 PFASs that have been phased out, are more soluble and were identified in some core layers at depths corresponding to pre-production periods. Thus, analyses of temporal trends of these more soluble compounds in cores of sediments were less accurate. Total elemental fluorine (TF) and extractable organic fluorine (EOF) indicated that identified PFASs were not a significant fraction of fluorine containing compounds in sediment (<0.01% in EOF). Copyright © 2018 Elsevier Ltd. All rights reserved.

Challenges to Lake Superior's Condition, Assessment, and Management: A Few Observations Across a Generation of Change

EPA Science Inventory

Selected comparisons of water quality and biological properties in lakewide samplings of 1970s and 2005/2006 provide a simple illustration of significant changes within Lake Superior in the last three decades. Observations of warmed surface layers, increased nitrate and increase...

Attenuation of landscape signals through the coastal zone: A basin-wide analysis for the US Great Lakes shoreline, circa 2002-2010

EPA Science Inventory

We compare statistical models developed to describe a) the relationship between watershed properties and Great Lakes coastal wetlands with b) the relationship developed between watershed properties and the Great Lakes nearshore. Using landscape metrics from the GLEI project (Dan...

Nearshore habitat and fish community associations of coaster brook trout in Isle Royale, Lake Superior

USGS Publications Warehouse

Gorman, O.T.; Moore, S.A.; Carlson, A.J.; Quinlan, H.R.

2008-01-01

We characterized the nearshore habitat and fish community composition of approximately 300 km of shoreline within and adjacent to the major embayments of Isle Royale, Lake Superior. Sampling yielded 17 species, of which 12 were widespread and represented a common element of the Lake Superior fish community, including cisco Coregonus artedi, lake whitefish C. clupeaformis, round whitefish Prosopium cylindraceum, lake trout Salvelinus namaycush, rainbow smelt Osmerus mordax, lake chub Couesius plumbeus, longnose sucker Catostomus catostomus, white sucker C. commersonii, trout-perch Percopsis omiscomaycus, ninespine stickleback Pungitius pungitius, burbot Lota lota, and slimy sculpin Cottus cognatus. The presence of brook trout S. fontinalis in an embayment was associated with the common species of the Isle Royale nearshore fish community, particularly cisco, longnose sucker, and round whitefish. However, brook trout were present in only five embayments and were common only in Tobin Harbor. Most Isle Royale embayments had broadly overlapping ranges of nearshore habitats. Within embayments, fish were distributed along a habitat gradient from less-protected rocky habitat near the mouth to highly protected habitat with mixed and finer substrates at the head. Embayments with brook trout had greater mean protection from the open lake, greater variation in depth, greater mean cover, and higher mean frequencies of large substrates (cobble, boulder, and bedrock). Within those embayments, brook trout were associated with habitat patches with higher mean frequencies of small substrates (particularly sand and coarse gravel). Within Tobin Harbor, brook trout were associated with midembayment habitat and species assemblages, especially those locations with a mixture of sand, gravel, and cobble substrates, an absence of bedrock, and the presence of round whitefish, white sucker, and trout-perch. Comparison of embayments with the model, Tobin Harbor, showed that six embayments

Age, growth and sex composition of the American smelt Osmerus mordax(Mitchill), of western Lake Superior

USGS Publications Warehouse

Bailey, Merryll M.

1964-01-01

This study is based on 4,561 smelt collected in Chequamegon Bay, the Apostle Islands, the Brule River, and Superior Harbor, all in western Lake Superior. Commercial production in the Great Lakes (U.S. and Canada combined) reached a peak of nearly 16 million pounds in 1960. Production in Lake Superior has generally been small but increased during the 1950's to reach 948,000 pounds in 1960. All O-group and spring I-group smelt had scales with sufficient sculpturing to permit detection of the first annulus. Annulus formation began after 6 June in 1960. In 1961, all smelt had completed the annulus by 24 August. The body-scale relation is a straight line with an intercept of -0.9 inch on the axis of fish length. The weight of western Lake Superior smelt increased as the 2.952 power of the length. A large range of length in each age group and resulting overlap of age-groups II-VI made length a poor index of age. Female smelt grew faster than males after the second year and dominated strongly in age-groups IV-VII. Both sexes made their best annual growth in length (3.3 inches) during their second year of life; the largest weight increments (0.74 ounce, males; 0.85 ounce, females) came in the third year. Best production from a commercial pound net in 1961 occurred when the sex ratios of spawning smelt were nearest 50:50. Spawning male smelt were consistently shorter than females and the average lengths of both sexes decreased as the spawning season progressed. Shortest mature smelt of each sex were 5.0 to 5.2 inches but the males are probably the first to reach 100 percent maturity. All year-old smelt were immature. Among 2-year-old fish, 40.7 per cent of the males and 17.7 percent of the females had reached maturity. All smelt more than 2 years old were mature. Ovaries of 10 smelt contained an average of 31,338 eggs for fish 7.3 to 8.8 inches long.

National Assessment of Historical Shoreline Change: A Pilot Study of Historical Coastal Bluff Retreat in the Great Lakes, Erie, Pennsylvania

USGS Publications Warehouse

Hapke, Cheryl J.; Malone, Shamus; Kratzmann, Meredith G.

2009-01-01

Coastal bluff retreat is a chronic problem along many high-relief coastlines in the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information regard-ing trends and rates of bluff retreat. There is also a need for a comprehensive analysis that is consistent from one coastal region to another. To address these national needs, the U.S. Geological Survey (USGS), as part of the National Assessment of Coastal Change Hazards Project, conducted a pilot study of bluff retreat along the Lake Erie, Pa., coastline to assess the feasibility of undertaking a larger, multi-state analysis in the Great Lakes region. This report provides an overview of the pilot-study location and bluff geomorphology, the data sources and methodology, results of the analysis, and a discussion of the feasibility of undertaking a similar analysis along eroding bluffs in other Great Lakes states. This pilot study is part of an ongoing effort by the USGS to provide a comprehensive analysis of historical shoreline change and cliff and bluff retreat along open-ocean coastlines of the conterminous United States and parts of Hawaii, Alaska, and the Great Lakes. One purpose of the work is to develop standard, repeatable methods for mapping and analyzing coastal change so that systematic and consistent periodic updates of coastal erosion can be made nationally. Bluff-retreat evaluations are conducted by comparing the location of a historical bluff edge digitized from aerial photographs with those of recent bluff edges interpreted from both aerial photographs and lidar topographic surveys. The historical bluff edge is from 1938, whereas the more recent bluff edges are from 1998 and 2006 lidar data. Long-term (68-year) rates of retreat are calculated using the available bluff-edge data. The rates of retreat presented in this report represent conditions from the 1930s to 1998/2006, and are not intended for

Use of classification trees to apportion single echo detections to species: Application to the pelagic fish community of Lake Superior

USGS Publications Warehouse

Yule, Daniel L.; Adams, Jean V.; Hrabik, Thomas R.; Vinson, Mark R.; Woiak, Zebadiah; Ahrenstroff, Tyler D.

2013-01-01

Acoustic methods are used to estimate the density of pelagic fish in large lakes with results of midwater trawling used to assign species composition. Apportionment in lakes having mixed species can be challenging because only a small fraction of the water sampled acoustically is sampled with trawl gear. Here we describe a new method where single echo detections (SEDs) are assigned to species based on classification tree models developed from catch data that separate species based on fish size and the spatial habitats they occupy. During the summer of 2011, we conducted a spatially-balanced lake-wide acoustic and midwater trawl survey of Lake Superior. A total of 51 sites in four bathymetric depth strata (0–30 m, 30–100 m, 100–200 m, and >200 m) were sampled. We developed classification tree models for each stratum and found fish length was the most important variable for separating species. To apply these trees to the acoustic data, we needed to identify a target strength to length (TS-to-L) relationship appropriate for all abundant Lake Superior pelagic species. We tested performance of 7 general (i.e., multi-species) relationships derived from three published studies. The best-performing relationship was identified by comparing predicted and observed catch compositions using a second independent Lake Superior data set. Once identified, the relationship was used to predict lengths of SEDs from the lake-wide survey, and the classification tree models were used to assign each SED to a species. Exotic rainbow smelt (Osmerus mordax) were the most common species at bathymetric depths 100 m (384 million; 6.0 kt). Cisco (Coregonus artedi) were widely distributed over all strata with their population estimated at 182 million (44 kt). The apportionment method we describe should be transferable to other large lakes provided fish are not tightly aggregated, and an appropriate TS-to-L relationship for abundant pelagic fish species can be determined.

Patterns in Habitat and Fish Assemblages within Great Lakes Coastal Wetlands and Implications for Sampling Design

EPA Science Inventory

Discerning fish - habitat associations at a variety of spatial scales is relevant to evaluating stressor responses and assessment protocols in Great Lakes coastal wetlands. NMDS ordination of electrofishing catch-per-effort data identified an overriding influence of geography an...

Turbidity in extreme western Lake Superior. [contamination of Duluth, Minnesota water intake

NASA Technical Reports Server (NTRS)

Sydor, M.

1975-01-01

Data were obtained from ERTS images for western Lake Superior for 1972-74. Data examination showed that for easterly winds the turbidity originating along the Wisconsin shore and the resuspension areas are transported northward then out along a N.E. path where it disperses, and often, for large storms, contaminates the Duluth water intake. Contaminants such as dredging fines anywhere along these paths would likewise find their way to the intake areas in concentrations comparable to the relative red clay concentration.

Phase 2 development of Great Lakes algorithms for Nimbus-7 coastal zone color scanner

NASA Technical Reports Server (NTRS)

Tanis, Fred J.

1984-01-01

A series of experiments have been conducted in the Great Lakes designed to evaluate the application of the NIMBUS-7 Coastal Zone Color Scanner (CZCS). Atmospheric and water optical models were used to relate surface and subsurface measurements to satellite measured radiances. Absorption and scattering measurements were reduced to obtain a preliminary optical model for the Great Lakes. Algorithms were developed for geometric correction, correction for Rayleigh and aerosol path radiance, and prediction of chlorophyll-a pigment and suspended mineral concentrations. The atmospheric algorithm developed compared favorably with existing algorithms and was the only algorithm found to adequately predict the radiance variations in the 670 nm band. The atmospheric correction algorithm developed was designed to extract needed algorithm parameters from the CZCS radiance values. The Gordon/NOAA ocean algorithms could not be demonstrated to work for Great Lakes waters. Predicted values of chlorophyll-a concentration compared favorably with expected and measured data for several areas of the Great Lakes.

Analysis of fish movements between Great Lakes coastal wetlands and near shore habitat via otolith microchemistry

EPA Science Inventory

Great Lakes coastal wetlands are unique habitats with physical connections with near shore environments. This facilitates the exchange of energy between habitats in a principle known as habitat coupling. Coupling can be facilitated by movements of consumers; however, wetland us...

An approach to the coastal water circulation in the Piratuba Lake Biological Reservation, Northeast of Amapa State, Brazil

NASA Astrophysics Data System (ADS)

Takiyama, L. R.; Silveira, O. M.

2007-05-01

This study shows the pioneer results of the water quality characterization of a lake region, including the Piratuba lake (within the limits of the Piratuba Lake Biological Reservation) and the Sucuriju river, localized at the northeast portion of the Amapa State, Brazil, and left margin of the Amazon River mouth. Due to the influence of the Amazon river and another important river, the Araguari river, the northeast coast of Amapa State receive little impact of salty water from the Atlantic ocean. The highest salinity values detected on this coastal area is 20 psu. The Piratuba Lake region which can be described as an unique wetland system formed by recent geological processes (Quaternary), it constitutes a very fragile environment and possesses a number of shallow water lakes distributed into a mixed mangrove and "varzea" type of vegetation and it is considered very important looking at the biological point of view. The borderline between this lake system with the coastal waters is a narrow portion of mangrove containing species of Rizhophora and Avicennia parallel to the coast line. A preliminary water circulation could be accessed through the detection of variation in water quality parameters throughout three field studies conducted on March, 2004, June 2005 and November 2005. Surface water sampling points spatially distributed on the study area with distances less than 2 km were set, covering almost 800 square kilometers. Among the parameters studied (pH, electrical conductivity, turbidity, concentration of suspended solids, depth, temperature, chloride, dissolved oxygen, nitrate, nitrite and phosphate) the turbidity, electrical conductivity and pH were the most important for identifying the entering of coastal waters into the lake region. Mainly, three points of direct contact were identified; one of them is a manmade illegal entrance to the Biological Reservation. The seasonal variation was also very important factor and as expected, during the dry season

Status and trends of prey fish populations in Lake Superior, 2008

USGS Publications Warehouse

Gorman, Owen T.; Evrard, Lori M.; Cholwek, Gary A.; Falck, Jill M.; Yule, Daniel

2009-01-01

The Great Lakes Science Center has conducted annual daytime bottom trawl surveys of the Lake Superior nearshore (15-80 m bathymetric depth zone) every spring since 1978 to provide a long-term index of relative abundance and biomass of the fish community. Between May 5 and June 14, 2008, 58 stations were sampled around the perimeter of the lake with 12-m wide bottom trawls. Trawls were deployed cross-contour at median start and end depths of 17 and 55 m, respectively. The lakewide mean relative biomass estimate for the entire fish community was 4.61 kg/ha which was similar to that measured in 2007, 4.81 kg/ha. Dominant species in the catch were lake whitefish, rainbow smelt, longnose sucker and cisco, which represented 49, 18, 11, and 7 % of the total community biomass, respectively. Compared to 2007 levels, lake whitefish and cisco biomass increased 35% and 55%, respectively, while bloater and rainbow smelt biomass declined 69% and 41%, respectively. Increased biomass of lake whitefish and decreased biomass in bloater represent trends observed since 2007; however, reversed trends in biomass were observed for cisco and rainbow smelt. Year-class strength for the 2007 cisco cohort (0.20 fish/ha) was below the long-term (1977-2007) average (73.31 fish/ha), as was year-class strength for the 2007 bloater cohort (0.33 fish/ha) compared to the long-term average (11.11 fish/ha). Smelt year class strength (226.26 fish/ha) continues a trend of increasing strength from a 31-year low of 56.75 fish/ha in 2001 and was above the long-term average of 193.81 fish/ha. The 2008 cisco age structure was dominated by age 5 and older fish, which accounted for 82% of the mean relative density. Wisconsin waters continue to be the most productive (mean total community biomass of 17.09 kg/ha), followed by western Ontario (5.40 kg/ha), eastern Ontario (3.08 kg/ha), Michigan (2.82 kg/ha), and Minnesota (0.89 kg/ha).Densities of small (400 mm) hatchery lake trout continued a pattern of decline

Age and growth of the whitefish in Lake Superior

USGS Publications Warehouse

Dryer, William R.

1963-01-01

The average annual commercial production of whitefish in the U.S. waters of Lake Superior dropped from 2,194,000 pounds in 1879-1908 to 504,000 pounds in 1911-59. The modern production, though far below the earlier, has accounted for more than 10 percent of the total value of the fishery in all but one of the last 20 years. Data are given on growth rate, age and year-class composition, size distribution, and length-weight relation of 1,800 fish collected in 1957-59 at Bayfield, Wis., and Marquette, Whitefish Point, and Dollar Settlement, Mich. Studies of the body-scale relation, sex ratio, and age and size at maturity were limited to fish collected at Bayfield. The age composition and mean age varied widely by port and year of capture. Oldest fish were those of the 1957 Bayfield samples which were dominated by age group VII and averaged 5.5 years old. The youngest were from Whitefish Point in 1959; age-group III was dominant, and the mean age was 3.2 years. The evidence on the strength of year classes was not clear-cut, but it was obvious that fluctuations in stocks of different areas were largely independent. The percentage of legal-size fish (17 inches or longer) in age groups ranged widely; only 8.6 percent of the V group were legal in the 1957 Bayfield collections, whereas 100 percent of fish of the same age were legal in the 1957-59 collections from Whitefish Point. The weight of whitefish in the combined samples increased as the 3.2408 power of the length. The growth rate from the fastest to the slowest growing stocks ranked as follows: Whitefish Point; Dollar Settlement and Marquette (fish from the two ports reversed ranks after 3 years); Bayfield. The major differences in growth in length among the various stocks occurred during the first years of life. Beyond the fifth year the annual increments were nearly the same in all stocks. The whitefish from Whitefish Point, Dollar Settlement, and Marquette are among the fastest growing in the Great Lakes. The

Biotic and abiotic factors related to rainbow smelt recruitment in the Wisconsin waters of Lake Superior, 1978-1997

USGS Publications Warehouse

Hoff, Michael H.

2004-01-01

Lake Superior rainbow smelt (Osmerus mordax) recruitment to 12-13 months of age in the Wisconsin waters of Lake Superior varied by a factor of 9.3 during 1978-1997. Management agencies have sought models that accurately predict recruitment, but no satisfactory models had previously been developed. In this study, modeling was conducted to determine which factors best explained recruitment variability. The Ricker stock-recruitment model derived from only the paired stock and recruit data accounted for 63% of the variability in recruitment data. The functional relationship that accounted for the greatest amount of recruitment variation (81%) included rainbow smelt stock size, May rainfall, and bloater (Coregonus hoyi) biomass. Model results were interpreted to mean that recruitment was affected negatively by increased river flows from increased rainfall, and affected positively by the biomass of bloater, and those results were interpreted to mean that bloater mediated the effects of lake trout predation on rainbow smelt recruits. Model results were also interpreted to mean that stock size caused compensatory, density-dependent mortality on rainbow smelt recruits. Correlations observed here may be of value to managers seeking approaches to either enhance or control populations of this species, which is not indigenous to the Great Lakes.

Great Lakes Maps - NOAA's National Weather Service

Science.gov Websites

Coastal Forecast System) Waves (GLERL Great Lakes Coastal Forecast System) Ice Cover (GLERL Great Lakes Coastal Forecast System) NOAA's National Weather Service Central Region Headquarters Regional Office 7220

Development of Great Lakes algorithms for the Nimbus-G coastal zone color scanner

NASA Technical Reports Server (NTRS)

Tanis, F. J.; Lyzenga, D. R.

1981-01-01

A series of experiments in the Great Lakes designed to evaluate the application of the Nimbus G satellite Coastal Zone Color Scanner (CZCS) were conducted. Absorption and scattering measurement data were reduced to obtain a preliminary optical model for the Great Lakes. Available optical models were used in turn to calculate subsurface reflectances for expected concentrations of chlorophyll-a pigment and suspended minerals. Multiple nonlinear regression techniques were used to derive CZCS water quality prediction equations from Great Lakes simulation data. An existing atmospheric model was combined with a water model to provide the necessary simulation data for evaluation of the preliminary CZCS algorithms. A CZCS scanner model was developed which accounts for image distorting scanner and satellite motions. This model was used in turn to generate mapping polynomials that define the transformation from the original image to one configured in a polyconic projection. Four computer programs (FORTRAN IV) for image transformation are presented.

Nearshore coastal mapping. [in Lake Michigan and Puerto Rico

NASA Technical Reports Server (NTRS)

Polcyn, F. C.; Lyzenga, D. R.

1975-01-01

Two test sites of different water quality and bottom topography were used to test for maximum water depth penetration using the Skylab S-192 MSS for measurement of nearshore coastal bathymetry. Sites under investigation lie along the Lake Michigan coastline where littoral transport acts to erode sand bluffs and endangers developments along 1,200 miles of shore, and on the west coast of Puerto Rico where unreliable shoal location and depth information constitutes a safety hazard to navigation. The S-192 and S-190A and B provide data on underwater features because of water transparency in the blue/green portion of the spectrum. Depth of 20 meters were measured with the S-192 in the Puerto Rico test site. The S-190B photography with its improved spatial resolution clearly delineates the triple sand bar topography in the Lake Michigan test site. Several processing techniques were employed to test for maximum depth measurement with least error. The results are useful for helping to determine an optimum spectral bandwidth for future space sensors that will increase depth measurements for different water attenuation conditions where a bottom reflection is detectable.

Time trends (1983-1999) for organochlorines and polybrominated diphenyl ethers in rainbow smelt (Osmerus mordax) from Lakes Michigan, Huron and Superior, USA

USGS Publications Warehouse

Chernyak, Sergei M.; Rice, Clifford P.; Quintal, Richard T.; Begnoche, Linda J.; Hickey, James P.; Vinyard, Bryan T.

2005-01-01

The U.S. Geological Service Great Lakes Science Center has archived rainbow smelt (Osmerus mordax) collected from the early 1980s to the present. These fish were collected to provide time- and site-dependent contaminant residue data needed by researchers and managers to fill critical data gaps regarding trends and behavior of persistent organic contaminants in the Great Lakes ecosystem. In the present study, data are presented for concentrations of several organochlorine (OC) contaminants in the archived smelt, including DDT, polychlorinated biphenyls (PCBs), toxaphene, and chlordanes in Lakes Michigan and Huron (MI, USA) and in Lake Superior (MN, USA). The trends for all the OCs were declining as a first-order decay over the sampled time series (1983/1985–1993/1999) with the exception of toxaphene in Lake Superior and PCBs at the Charlevoix/Little Traverse Bay site in Lake Michigan. Concentration of the emerging contaminant, polybrominated diphenyl ethers (PBDEs), also was traced from its apparent entry into this ecosystem in approximately 1980 until 1999. Time trends for the PBDEs were increasing exponentially at all sites, with concentration-doubling times varying from 1.58 to 2.94 years.

Evaluating the importance of abiotic and biotic drivers on Bythotrephes biomass in Lakes Superior and Michigan

USGS Publications Warehouse

Keeler, Kevin M.; Bunnell, David B.; Diana, James S.; Adams, Jean V.; Mychek-Londer, Justin G.; Warner, David M.; Yule, Daniel; Vinson, Mark

2015-01-01

The ability of planktivorous fishes to exert top-down control on Bythotrephes potentially has far-reaching impacts on aquatic food-webs, given previously described effects of Bythotrephes on zooplankton communities. We estimated consumption of Bythotrephes by planktivorous and benthivorous fishes, using bioenergetics and daily ration models at nearshore (18 m), intermediate (46 m), and offshore (110 m) depths along one western Lake Superior transect (April, and September-November) and two northern Lake Michigan transects (April, July, September). In Lake Superior, consumption (primarily by cisco Coregonus artedi) exceeded Bythotrephes production at all offshore sites in September-November (up to 396% of production consumed) and at the intermediate site in November (842%) with no evidence of consumption nearshore. By comparing Bythotrephes biomass following months of excessive consumption, we conservatively concluded that top-down control was evident only at the offshore site during September-October. In Lake Michigan, consumption by fishes (primarily alewife Alosa pseudoharengus) exceeded production at nearshore sites (up to 178%), but not in deeper sites (< 15%). Evidence for top-down control in the nearshore was not supported, however, as Bythotrephes never subsequently declined. Using generalized additive models, temperature, and not fish consumption, not zooplankton prey density, best explained variability in Bythotrephes biomass. The non-linear pattern revealed Bythotrephes to increase with temperature up to 16 °C, and then decline between 16 and 23 °C. We discuss how temperature likely has direct negative impacts on Bythotrephes when temperatures near 23 °C, but speculate that predation also contributes to declining biomass when temperatures exceed 16 °C.

Ecological, biogeochemical and salinity changes in coastal lakes and wetlands over the last 200 years

NASA Astrophysics Data System (ADS)

Roberts, Lucy; Holmes, Jonathan; Horne, David

2016-04-01

Shallow lakes provide extensive ecosystem services and are ecologically important aquatic resources supporting a diverse flora and fauna. In marginal-marine areas, where such lakes are subjected to the multiple pressures of coastal erosion, sea level rise, increasing sea surface temperature and increasing frequency and intensity of storm surges, environments are complex and unstable. They are characterised by physico-chemical variations due to climatic (precipitation/evaporation cycles) and dynamic factors (tides, currents, freshwater drainage and sea level changes). Combined with human activity in the catchment these processes can alter the salinity, habitat and ecology of coastal fresh- to brackish water ecosystems. In this study the chemical and biological stability of coastal lakes forming the Upper Thurne catchment in the NE of the Norfolk Broads, East Anglia, UK are seriously threatened by long-term changes in salinity resulting from storm surges, complex hydrogeology and anthropogenic activity in the catchment. Future management decisions depend on a sound understanding of the potential ecological impacts, but such understanding is limited by short-term observations and measurements. This research uses palaeolimnological approaches, which can be validated and calibrated with historical records, to reconstruct changes in the aquatic environment on a longer time scale than can be achieved by observations alone. Here, salinity is quantitatively reconstructed using the trace-element geochemistry (Sr/Ca and Mg/Ca) of low Mg-calcite shells of Ostracoda (microscopic bivalved crustaceans) and macrophyte and macroinvertebrate macrofossil remains are used as a proxy to assess ecological change in response to variations in salinity. δ13C values of Cladocera (which are potentially outcompeted by the mysid Neomysis integer with increasing salinity and eutrophication) can be used to reconstruct carbon cycling and energy pathways in lake food webs, which alongside

Remotely Sensing Lake Water Volumes on the Inner Arctic Coastal Plain of Northern Alaska

NASA Astrophysics Data System (ADS)

Simpson, C. E.; Arp, C. D.; Jones, B. M.; Hinkel, K. M.; Carroll, M.; Smith, L. C.

2017-12-01

Thermokarst lake depth is controlled by the amount of excess ice in near-surface permafrost, with lake depths of about 1 - 3 m in areas of epigenetic permafrost and over 10 m in areas of syngenetic permafrost. An important exception to these general patterns is found on the inner Arctic Coastal Plain (ACP) of northern Alaska, where deep lakes occur in Pleistocene-aged, ground-ice poor sandy terrain. These lakes cover 20% of the currently inactive sand sheet and dune deposit (referred to as the Pleistocene Sand Sea) that comprises approximately 7000 km2 of the ACP. Surrounded by high and eroding bluffs, sand sea lakes lie in natural depressions and are characterized by wide, shallow littoral shelves and central troughs that are typically oriented NNW to SSE and can reach depths greater than 20 m. Despite their unique form and extensive coverage, these lakes have received little prior study and a literature gap remains regarding regional water storage. This research classifies sand sea lakes, estimates individual lake volume, and provides a first quantification of water storage in a region of the lake-dominated ACP. We measured bathymetric profiles in 19 sand sea lakes using a sonar recorder to capture various lake depth gradients. Bathymetric surveys collected by oil industry consultants, lake monitoring programs, and habitat studies serve as additional datasets. These field measured lake depth data points were used to classify Color Infrared Photography, WorldView-2 satellite imagery, and Landsat-OLI satellite imagery to develop a spectral depth-classification algorithm and facilitate the interpolation of the bathymetry for study lakes in the inner ACP. Finally, we integrate the remotely sensed bathymetry and imagery-derived lake surface area to estimate individual and regional-scale lake volume. In addition to the natural function of these lakes in water storage, energy balance, and habitat provision, the need for winter water supply to build ice roads for oil

Lake Superior Zooplankton Biomass Predictions from LOPC Tow Surveys Compare Well with a Probability Based Net Survey

EPA Science Inventory

We conducted a probability-based sampling of Lake Superior in 2006 and compared the zooplankton biomass estimate with laser optical plankton counter (LOPC) predictions. The net survey consisted of 52 sites stratified across three depth zones (0-30, 30-150, >150 m). The LOPC tow...

Seasonally dynamic diel vertical migrations of Mysis diluviana, coregonine fishes, and siscowet lake trout in the pelagia of western Lake Superior

USGS Publications Warehouse

Ahrenstorff, Tyler D.; Hrabik, Thomas R.; Stockwell, Jason D.; Yule, Daniel L.; Sass, Greg G.

2011-01-01

Diel vertical migrations are common among many aquatic species and are often associated with changing light levels. The underlying mechanisms are generally attributed to optimizing foraging efficiency or growth rates and avoiding predation risk (μ). The objectives of this study were to (1) assess seasonal and interannual changes in vertical migration patterns of three trophic levels in the Lake Superior pelagic food web and (2) examine the mechanisms underlying the observed variability by using models of foraging, growth, and μ. Our results suggest that the opossum shrimp Mysis diluviana, kiyi Coregonus kiyi, and siscowet lake trout Salvelinus namaycush migrate concurrently during each season, but spring migrations are less extensive than summer and fall migrations. In comparison with M. diluviana, kiyis, and siscowets, the migrations by ciscoes C. artedi were not as deep in the water column during the day, regardless of season. Foraging potential and μ probably drive the movement patterns of M. diluviana, while our modeling results indicate that movements by kiyis and ciscoes are related to foraging opportunity and growth potential and receive a lesser influence from μ. The siscowet is an abundant apex predator in the pelagia of Lake Superior and probably undertakes vertical migrations in the water column to optimize foraging efficiency and growth. The concurrent vertical movement patterns of most species are likely to facilitate nutrient transport in this exceedingly oligotrophic ecosystem, and they demonstrate strong linkages between predators and prey. Fishery management strategies should use an ecosystem approach and should consider how altering the densities of long-lived top predators produces cascading effects on the nutrient cycling and energy flow in lower trophic levels.

Paleoecology of a Northern Michigan Lake and the relationship among climate, vegetation, and Great Lakes water levels

USGS Publications Warehouse

Booth, R.K.; Jackson, S.T.; Thompson, T.A.

2002-01-01

We reconstructed Holocene water-level and vegetation dynamics based on pollen and plant macrofossils from a coastal lake in Upper Michigan. Our primary objective was to test the hypothesis that major fluctuations in Great Lakes water levels resulted in part from climatic changes. We also used our data to provide temporal constraints to the mid-Holocene dry period in Upper Michigan. From 9600 to 8600 cal yr B.P. a shallow, lacustrine environment characterized the Mud Lake basin. A Sphagnum-dominated wetland occupied the basin during the mid-Holocene dry period (???8600 to 6600 cal yr B.P.). The basin flooded at 6600 cal yr B.P. as a result of rising water levels associated with the onset of the Nipissing I phase of ancestral Lake Superior. This flooding event occured contemporaneously with a well-documented regional expansion of Tsuga. Betula pollen increased during the Nipissing II phase (4500 cal yr B.P.). Macrofossil evidence from Mud Lake suggests that Betula alleghaniensis expansion was primarily responsible for the rising Betula pollen percentages. Major regional and local vegetational changes were associated with all the major Holocene highstands of the western Great Lakes (Nipissing I, Nipissing II, and Algoma). Traditional interpretations of Great Lakes water-level history should be revised to include a major role of climate. ?? 2002 University of Washington.

ELEMENTAL MERCURY IN COPPER, SILVER, AND GOLD ORES: AN UNEXPECTED CONTRIBUTION TO LAKE SUPERIOR SEDIMENTS WITH GLOBAL IMPLICATIONS

EPA Science Inventory

Mercury and copper inventories are low in central Lake Superior and increase markedly towards the Keweenaw Peninsula...where copper, mercury, and silver inventories are elevated and highly correlated. High copper, silver, and mercury inventories can be traced back to shoreline st...

HYPERSPECTRAL REMOTE SENSING, GPS, AND GIS APPLICATIONS IN OPPORTUNISTIC PLANT SPECIES MONITORING OF GREAT LAKES COASTAL WETLANDS

EPA Science Inventory

Coastal wetlands of the Laurentian Great Lakes (LGL) are among the most fragmented and disturbed ecosystems of the world, with a long history of human-induced disturbance. LGL wetlands have undergone losses in the biological diversity that coincides with an increase in the presen...

Using radon-222 and radium-226 isotopes to deduce the functioning of a coastal aquifer adjacent to a hypersaline lake in NW Iran

NASA Astrophysics Data System (ADS)

Amiri, Vahab; Nakhaei, Mohammad; Lak, Razyeh

2017-10-01

This study aims to assess the hydrogeochemistry of coastal groundwater, the occurrence of 222Rn and 226Ra, and their isotopic response to salinity and associated chemical compositions of groundwater in the coastal Urmia Aquifer (UA) at the western side of Urmia Lake (UL). The results of the PCA show that 87.3% of groundwater chemistry changes are controlled by six principal components. The interaction between groundwater and coastal igneous and metamorphic rocks in eastern areas (next to the UL) results in complex hydrogeochemical conditions than western areas. Based on correlation of U and salinity, some coastal samples display conservative and the others non-conservative behaviors. Differed from most previous studies, 226Ra and 222Rn concentrations in coastal groundwater samples of UA do not show a good correlation with salinity. Given 10% of groundwater 222Rn is originated from host rocks, the radon concentrations recorded in the coastal groundwater samples are relatively in range that can effectively be supplied by the local rocks (5-49 Bq/l). Results of different chemical and isotopic parameters in this area indicate that there is no direct connection between fresh groundwater and UL saltwater. This is because that the hard and thick salty layer in the lakebed acts as an impermeable barrier to prevent the underground hydraulic connection. Results show that removing the salty layer of UL as an option to progress in rehabilitation program of this lake may result in more hydraulic connection between the lake and groundwater resources in some areas.

REGIONAL, WATERSHED, AND SITE-SPECIFIC ENVIRONMENTAL INFLUENCES ON FISH ASSEMBLAGE STRUCTURE AND FUNCTION IN WESTERN LAKE SUPERIOR TRIBUTARIES

EPA Science Inventory

The relative importance of regional, watershed, and in-stream environmental factors on stream fish assemblage structure and function was investigated as part of a comparative watershed project in the western Lake Superior basin. We selected 48 second and third order watersheds fr...

Examining indirect effects of lake trout recovery

EPA Science Inventory

With the recovery of lake trout populations in Lake Superior, there are indications of decreased forage fish abundance and density-dependence in lake trout. In Lake Superior, lean lake trout historically occupied depths < 60 m, and siscowet lake trout occupied depths > 60 m...

75 FR 35294 - Safety Zone; Marquette 4th of July Fireworks, Marquette Harbor, Lake Superior, Marquette, MI

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-22

...-AA00 Safety Zone; Marquette 4th of July Fireworks, Marquette Harbor, Lake Superior, Marquette, MI... vessels from a portion of Marquette Harbor during the Marquette 4th of July Fireworks display. This... vessels during the setup and launching of fireworks in conjunction with the Marquette 4th of July...

75 FR 38721 - Safety Zone; Munising 4th of July Fireworks, South Bay, Lake Superior, Munising, MI

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-06

...-AA00 Safety Zone; Munising 4th of July Fireworks, South Bay, Lake Superior, Munising, MI AGENCY: Coast... portion of South Bay during the Munising 4th of July Fireworks display, July 4, 2010. This temporary... from hazards associated with the Munising 4th of July Fireworks display. Based on the explosive hazards...

A post-Calumet shoreline along southern Lake Michigan

USGS Publications Warehouse

Capps, D.K.; Thompson, T.A.; Booth, R.K.

2007-01-01

The southern shore of Lake Michigan is the type area for many of ancestral Lake Michigan's late Pleistocene lake phases, but coastal deposits and features of the Algonquin phase of northern Lake Michigan, Lake Huron, and Lake Superior are not recognized in the area. Isostatic rebound models suggest that Algonquin phase deposits should be 100 m or more below modern lake level. A relict shoreline, however, exists along the lakeward margin of the Calumet Beach that was erosional west of Deep River and depositional east of the river. For this post-Calumet shoreline, the elevation of basal foreshore deposits east of Deep River and the base of the scarp west of Deep River indicate a slightly westward dipping water plane that is centered at ???184 m above mean sea level. Basal foreshore elevations also indicate that lake level fell ???2 m during the development of the shoreline. The pooled mean of radiocarbon dates from the surface of the peat below post-Calumet shoreline foreshore deposits indicate that the lake transgressed over the peat at 10,560 ?? 70 years B.P. Pollen assemblages from the peat are consistent with this age. The elevation and age of the post-Calumet shoreline are similar to the Main Algonquin phase of Lake Huron. Recent isostatic rebound models do not adequately address a high-elevation Algonquin-age shoreline along the southern shore of Lake Michigan, but the Goldthwait (1908) hinge-line model does. ?? 2006 Springer Science+Business Media B.V.

The biogenic reefs formed by the alien polychaete Hydroides dianthus (Serpulidae, Annelida) favor the polyp stage of Aurelia coerulea (Cnidaria, Scyphozoa) in a coastal artificial lake.

PubMed

Dong, Zhijun; Sun, Tingting; Wang, Lei

2018-04-01

Blooms of the moon jellyfish Aurelia coerulea frequently occur in coastal waters. The increased availability of substrates for the settlement and proliferation of polyps due to the expansion of artificial structures in coastal areas has been proposed as a possible contributing factor in jellyfish blooms. This paper investigates whether a marine artificial lake (Fenghuang Lake) provides additional substrates for A. coerulea polyps and contributes to jellyfish blooms. High densities of A. coerulea ephyrae were discovered in this lake, with a mean density of 41 individuals/m 3 and a maximum measured density of 128 individuals/m 3 . Meanwhile, A. coerulea ephyrae were also found in the two emptying channels outside the lake, with a mean density of 13 individuals/m 3 . Underwater surveys revealed that dense colonies of A. coerulea polyps occurred mainly on biogenic reefs formed by a polychaete, which was identified as an invasive serpulid species Hydroides dianthus, based on the phylogenetic analysis of mitochondrial COI gene sequences. Our study highlights the potential modification of habitats by the alien polychaete H. dianthus, which might provide complex benthic habits suitable for the settlement and proliferation of A. coerulea polyps and may contribute to jellyfish blooms in the marine artificial lake and nearby coastal waters. Copyright © 2018 Elsevier Ltd. All rights reserved.

Hydrogeomorphic processes of thermokarst lakes with grounded-ice and floating-ice regimes on the Arctic coastal plain, Alaska

USGS Publications Warehouse

Arp, C.D.; Jones, Benjamin M.; Urban, F.E.; Grosse, G.

2011-01-01

Thermokarst lakes cover > 20% of the landscape throughout much of the Alaskan Arctic Coastal Plain (ACP) with shallow lakes freezing solid (grounded ice) and deeper lakes maintaining perennial liquid water (floating ice). Thus, lake depth relative to maximum ice thickness (1·5–2·0 m) represents an important threshold that impacts permafrost, aquatic habitat, and potentially geomorphic and hydrologic behaviour. We studied coupled hydrogeomorphic processes of 13 lakes representing a depth gradient across this threshold of maximum ice thickness by analysing remotely sensed, water quality, and climatic data over a 35-year period. Shoreline erosion rates due to permafrost degradation ranged from L) with periods of full and nearly dry basins. Shorter-term (2004–2008) specific conductance data indicated a drying pattern across lakes of all depths consistent with the long-term record for only shallow lakes. Our analysis suggests that grounded-ice lakes are ice-free on average 37 days longer than floating-ice lakes resulting in a longer period of evaporative loss and more frequent negative P − EL. These results suggest divergent hydrogeomorphic responses to a changing Arctic climate depending on the threshold created by water depth relative to maximum ice thickness in ACP lakes.

Nutrient pressures and ecological responses to nutrient loading reductions in Danish streams, lakes and coastal waters

NASA Astrophysics Data System (ADS)

Kronvang, Brian; Jeppesen, Erik; Conley, Daniel J.; Søndergaard, Martin; Larsen, Søren E.; Ovesen, Niels B.; Carstensen, Jacob

2005-03-01

The Danish National Aquatic Monitoring and Assessment Programme (NOVA) was launched in 1988 following the adoption of the first Danish Action Plan on the Aquatic Environment in 1987 with the aim to reduce by 50% the nitrogen (N) loading and by 80% the phosphorus (P) loading to the aquatic environment. The 14 years of experience gathered from NOVA have shown that discharges of total N (TN) and P (TP) from point sources to the Danish Aquatic Environment have been reduced by 69% (N) and 82% (P) during the period 1989 2002. Consequently, the P concentration has decreased markedly in most Danish lakes and estuaries. Considerable changes in agricultural practice have resulted in a reduction of the net N-surplus from 136 to 88 kg N ha-1 yr-1 (41%) and the net P-surplus from 19 to 11 kg P ha-1 yr-1 (42%) during the period 1985 2002. Despite these efforts Danish agriculture is today the major source of both N (>80%) and P (>50%) in Danish streams, lakes and coastal waters. A non-parametric statistical trend analysis of TN concentrations in streams draining dominantly agricultural catchments has shown a significant (p<0.05) downward trend in 48 streams with the downward trend being stronger in loamy compared to sandy catchments, and more pronounced with increasing dominance of agricultural exploitation in the catchments. In contrast, a statistical trend analysis of TP concentrations in streams draining agricultural catchments did not reveal any significant trends. The large reduction in nutrient loading from point and non-point sources has in general improved the ecological conditions of Danish lakes in the form of increased summer Secchi depth, decreased chlorophyll a and reduced phytoplankton biomass. Major changes have also occurred in the fish communities in lakes, with positive cascading effects on water quality. In Danish estuaries and coastal waters only a few significant improvements in the ecological quality have been observed, although it is expected that the

Abundance indices for determining the status of lake trout restoration in Michigan waters of Lake Superior

USGS Publications Warehouse

Hansen, Michael J.; Schorfhaar, Richard G.; Peck, James W.; Selgeby, James H.; Taylor, William W.

1995-01-01

Self-sustaining populations of lake trout Salvelinus namaycush have returned to most areas in Lake Superior, but progress toward achieving historic commercial yields has been difficult to measure because of unrecorded losses to predation by sea lamprey Petromyzon marinus and to fisheries. Consequently, we developed restoration targets (catch per effort, CPE; geometric mean number per kilometer of 114-mm stretch-meaure gill net during 1929-1943, when historic yields were sustained) from linear relationships between CPE in commercial and assessment fisheries in Michigan. Target CPEs for lake trout restoration were higher and less variable than the modern CPEs in all areas. Modern CPEs generally increased during the 1970s and early 1980s but declined during the late 1980s and early 1990s. Modern CPEs were highest in western Michigan from the Keweenaw Peninsula to Marquette (71 to 81% of target CPEs), but coefficients of variation (CV,SD/mean) of mean CPEs were 1.4 to 2.4 times greater than target CVs. Around Munising, the modern CPE was lower (41% of the target CPE), whereas the CV was 1.9 times greater than the target CV. Around Grand Marais, the modern CPE was lowest among all areas (17% of the target CPE), but the CV was nearly the same (1.1 times the target CV). In Whitefish Bay, the modern CPE was only 28% of the target CPE and the CV was 9.0 times greater, though the modern period was based on only the years 1979-1982 and 1984-1985. Further progress in restoration in most areas can be achieved only if fishery managers adequately protect existing stocks of wild fish from sea lamprey predation and fishery exploitation.

ROSGREN STREAM TYPES AS A TOOL FOR PREDICTING BEDLOAD AND SUSPENDED SEDIMENT EXPORT IN LOW-ORDER LAKE SUPERIOR WATERSHEDS

EPA Science Inventory

Bedload samples were collected from 48 second and third order Lake Superior tributaries during snowmelt in 1998 and 1999. Suspended sediment samples were collected over a three-year period during baseflow, rain events, and snowmelt. This work was part of a comparative watershed...

AN ECOLOGICAL ASSESSMENT OF INVASIVE AND AGRESSIVE PLANT SPECIES IN COASTAL WETLANDS OF THE LAURENTIAN GREAT LAKES: A COMBINED FIELD BASED AND REMOTE SENSING APPROACH

EPA Science Inventory

The aquatic plant communities within coastal wetlands of the Laurentian Great Lakes are among the most biologically diverse and productive systems of the world. Coastal wetlands have been especially impacted by landscape conversion and have undergone a marked decline in plant com...

Using Stable Isotope Mixing in a Great Lakes Coastal Tributary to Determine Food Web Linkages in Young Fishes

EPA Science Inventory

Our objectives were to determine whether we can detect a stable isotope gradient along the river-Great Lake hydrologic continuum in a coastal river and use it to identify changes across this gradient in the food web supporting young-of-year (YOY) and juvenile fish production. We ...

Support of Coastal Fishes by Nearshore and Coastal Wetland Habitats

EPA Science Inventory

Hydrologic linkages among Great Lakes nearshore and coastal wetlands free coastal fish to move among the habitats, which has led to a variety of habitat use patterns. Fine-scale microchemical analyses of yellow perch otoliths have revealed life-history categories that include per...

THE WESTERN LAKE SUPERIOR COMPARATIVE WATERSHED FRAMEWORK: A FIELD TEST OF GEOGRAPHICALLY-DEPENDENT VS. THRESHOLD-BASED GEOGRAPHICALLY-INDEPENDENT CLASSIFICATION SCHEMES

EPA Science Inventory

Main and interactive effects of watershed storage and forest fragmentation on watershed exports, habitat quality, community composition and food-web relationships were compared within and acoss two hydrogeomorphic regions (HGM, North Shore Highlands and Lake Superior clay plains/...

Establishment Patterns of Non-native Fishes: Lessons from the Duluth-Superior Harbor and Lower St. Louis River, an Invasion-prone Great Lakes Freshwater Estuary

EPA Science Inventory

The St. Louis River freshwater estuary which drains into western Lake Superior and includes the Duluth-Superior (MN-WI) harbor, has a long history of non-native fish introductions. From 1985 to 2002, seven new fishes were identified in the estuary, an unprecedented rate of non-n...

Habitat use by fishes of Lake Superior. II. Consequences of diel habitat use for habitat linkages and habitat coupling in nearshore and offshore waters

USGS Publications Warehouse

Gorman, Owen T.; Yule, Daniel L.; Stockwell, Jason D.

2012-01-01

Diel migration patterns of fishes in nearshore (15–80 m depth) and offshore (>80 m) waters of Lake Superior were examined to assess the potential for diel migration to link benthic and pelagic, and nearshore and offshore habitats. In our companion article, we described three types of diel migration: diel vertical migration (DVM), diel bank migration (DBM), and no diel migration. DVM was expressed by fishes migrating from benthopelagic to pelagic positions and DBM was expressed by fishes migrating horizontally from deep to shallow waters at night. Fishes not exhibiting diel migration typically showed increased activity by moving from benthic to benthopelagic positions within demersal habitat. The distribution and biomass of fishes in Lake Superior was characterized by examining 704 bottom trawl samples collected between 2001 and 2008 from four depth zones: ≤40, 41–80, 81–160, and >160 m. Diel migration behaviors of fishes described in our companion article were applied to estimates of areal biomass (kg ha−1) for each species by depth zone. The relative strength of diel migrations were assessed by applying lake area to areal biomass estimates for each species by depth zone to yield estimates of lake-wide biomass (metric tonnes). Overall, species expressing DVM accounted for 83%, DBM 6%, and non-migration 11% of the total lake-wide community biomass. In nearshore waters, species expressing DVM represented 74% of the biomass, DBM 25%, and non-migration 1%. In offshore waters, species expressing DVM represented 85%, DBM 1%, and non-migration 14% of the biomass. Of species expressing DVM, 83% of total biomass occurred in offshore waters. Similarly, 97% of biomass of non-migrators occurred in offshore waters while 83% of biomass of species expressing DBM occurred in nearshore waters. A high correlation (R2 = 0.996) between lake area and community biomass by depth zone resulted in 81% of the lake-wide biomass occurring in offshore waters. Accentuating this

Spatial and Ontogenetic Variation in Mercury in Lake Superior Basin Sea Lamprey (Petromyzon marinus).

PubMed

Moses, Sara K; Polkinghorne, Christine N; Mattes, William P; Beesley, Kimberly M

2018-01-01

Mercury concentrations were measured in eggs, larvae, and adult spawning-phase sea lampreys (Petromyzon marinus) collected in tributaries of Lake Superior to investigate spatial and ontogenetic variation. There were significant differences in mercury concentrations between all three life stages, with levels highest in adults (mean = 3.01 µg/g), followed by eggs (mean = 0.942 µg/g), and lowest in larvae (mean = 0.455 µg/g). There were no significant differences in mercury concentrations by location for any life stage or by sex in adults. Mercury was not correlated with adult or larval lamprey length or mass. Mercury levels in adult lampreys exceeded U.S. and Canadian federal guidelines for human consumption. Mercury concentrations in all life stages exceeded criteria for the protection of piscivorous wildlife, posing a threat to local fish, birds, and mammals. High mercury levels in adult lampreys combined with their semelparous life history make them a potential source of lake-derived mercury to spawning streams.

Repeat surveys of spawning cisco (Coregonus artedi) in western Lake Superior: timing, distribution and composition of spawning stocks

USGS Publications Warehouse

Yule, Daniel L.; Schreiner, Donald R.; Addison, Peter A.; Seider, Michael J.; Evrard, Lori M.; Geving, Steven A.; Quinlan, Henry R.

2012-01-01

Acoustic (AC) and midwater trawl (MT) surveys of spawning cisco (Coregonus artedi) in Lake Superior have been combined with commercial yield to estimate exploitation. To time surveys properly, it is important to understand when adults typically arrive at spawning grounds and how numbers change as the spawning season progresses. We conducted repeat autumn surveys during nighttime hours at coastal sites where commercial roe fisheries occur. Spawner densities increased significantly from October to mid-November, but differences measured at sites sampled from mid- to late-November were comparatively small. Spawners occupied the upper 20–30 m of the water column during mid-November before utilizing a wider range of depths by late-November. We compared repeat AC densities to temporal trends of catch-per-unit-effort (CPUE) in suspended commercial gillnets and found good agreement within sites. Because different gillnet mesh sizes were used in each roe fishery. CPUE and AC density were poorly correlated among sites. We recommend that future surveys be conducted between mid- and late-November, and that MT gear be used to measure cisco densities in the uppermost 10 m of the water column where AC estimates may be conservative. Given the short temporal window for assessing spawner density, we believe both AC-MT and gillnet surveys will be needed to ensure that harvest of different stocks is kept at a sustainable level.

Experiencing the changing climate on the shores of Lake Superior

NASA Astrophysics Data System (ADS)

Akerlof, K.; Maibach, E.

2011-12-01

The Great Lakes of the United States - the largest freshwater system in the world - have been termed "the canary in the coal mine" of environmental change. To assess if and how residents of Alger County, Michigan are experiencing changes in climate on the shores of Lake Superior, during the summer of 2010 we conducted a representative household mail survey in collaboration with a national lakeshore and watershed partnership. A total of 765 adult residents (18 years or older) responded to the survey; a 57% survey completion rate. We content analyzed respondents' open-ended characterizations of how they have personally experienced global warming, and compared the results with land surface and storm data for the same geographic region to see whether public perceptions of local changes match trends in National Climatic Data Center data. Just over a quarter of residents (27%) indicated that they had personally experienced global warming. Those who had were most likely to say that they had experienced global warming locally (as opposed to in other locations of the country or globally), and most frequently cited changes in seasons, weather, lake levels, and animals or plant species. However, some local public perceptions appeared to conflict with weather records. For example, residents were more likely to say that they had been experiencing less snow in the winters, while NCDC data suggests the reverse is true. As climate changes differentially in regions across the United States, the public will in turn experience its physical impacts in distinct ways that are unique to each landscape. This may be counter-intuitive to a public that increasingly experiences the world, and issues such as climate change, through sources of information such as national news media that operate at much larger geographic scales. Understanding where these forms of cognitive dissonance may arise may assist researchers, educators, and communicators in furthering discourses with the public about

Optical dating of tsunami-laid sand from an Oregon coastal lake

USGS Publications Warehouse

Ollerhead, J.; Huntley, D.J.; Nelson, A.R.; Kelsey, H.M.

2001-01-01

Optical ages for five samples of tsunami-laid sand from an Oregon coastal lake were determined using an infrared optical-dating method on K-feldspar separates and, as a test of accuracy, compared to ages determined by AMS 14C dating of detrital plant fragments found in the same beds. Two optical ages were about 20% younger than calibrated 14C ages of about 3.1 and 4.3 ka. Correction of the optical ages using measured anomalous fading rates brings them into agreement with the 14C ages. The approach used holds significant promise for improving the accuracy of infrared optical-dating methods. Luminescence data for the other three samples result in optical age limits much greater than the 14C ages. These data provide a textbook demonstration of the correlation between scatter in the luminescence intensity of individual sample aliquots and their normalization values that is expected when the samples contain sand grains not adequately exposed to daylight just prior to or during deposition and burial. Thus, the data for these three samples suggest that the tsunamis eroded young and old sand deposits before dropping the sand in the lake. ?? 2001 Elsevier Science Ltd. All rights reserved.

An integrated assessment for wind energy in Lake Michigan coastal counties.

PubMed

Nordman, Erik; VanderMolen, Jon; Gajewski, Betty; Isely, Paul; Fan, Yue; Koches, John; Damm, Sara; Ferguson, Aaron; Schoolmaster, Claire

2015-04-01

The benefits and challenges of onshore and offshore wind energy development were assessed for a 4-county area of coastal Michigan. Economic, social, environmental, and spatial dimensions were considered. The coastal counties have suitable wind resources for energy development, which could contribute toward Michigan's 10% renewable energy standard. Wind energy is cost-effective with contract prices less than the benchmark energy price of a new coal-fired power plant. Constructing a 100 MW wind farm could have a $54.7 million economic impact. A patchwork of township-level zoning ordinances regulates wind energy siting. Voluntary collaborations among adjacent townships standardizing the ordinances could reduce regulatory complexity. A Delphi Inquiry on offshore wind energy in Lake Michigan elicited considerable agreement on its challenges, but little agreement on the benefits to coastal communities. Offshore turbines could be acceptable to the participants if they reduced pollution, benefited coastal communities, involved substantial public participation, and had minimal impact on property values and tourism. The US Coast Guard will take a risk-based approach to evaluating individual offshore developments and has no plans to issue blanket restrictions around the wind farms. Models showed that using wind energy to reach the remainder of the 10% renewable energy standard could reduce SO2 , NOx , and CO2 pollution by 4% to 7%. Turbines are highly likely to impact the area's navigational and defense radar systems but planning and technological upgrades can reduce the impact. The integrated assessment shows that responsible wind energy development can enhance the quality of life by reducing air pollution and associated health problems and enhancing economic development. Policies could reduce the negative impacts to local communities while preserving the benefits to the broader region. © 2015 SETAC.

Satellite remote sensing for modeling and monitoring of water quality in the Great Lakes

NASA Astrophysics Data System (ADS)

Coffield, S. R.; Crosson, W. L.; Al-Hamdan, M. Z.; Barik, M. G.

2017-12-01

Consistent and accurate monitoring of the Great Lakes is critical for protecting the freshwater ecosystems, quantifying the impacts of climate change, understanding harmful algal blooms, and safeguarding public health for the millions who rely on the Lakes for drinking water. While ground-based monitoring is often hampered by limited sampling resolution, satellite data provide surface reflectance measurements at much more complete spatial and temporal scales. In this study, we implemented NASA data from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite to build robust water quality models. We developed and validated models for chlorophyll-a, nitrogen, phosphorus, and turbidity based on combinations of the six MODIS Ocean Color bands (412, 443, 488, 531, 547, and 667nm) for 2003-2016. Second, we applied these models to quantify trends in water quality through time and in relation to changing land cover, runoff, and climate for six selected coastal areas in Lakes Michigan and Erie. We found strongest models for chlorophyll-a in Lake Huron (R2 = 0.75), nitrogen in Lake Ontario (R2=0.66), phosphorus in Lake Erie (R2=0.60), and turbidity in Lake Erie (R2=0.86). These offer improvements over previous efforts to model chlorophyll-a while adding nitrogen, phosphorus, and turbidity. Mapped water quality parameters showed high spatial variability, with nitrogen concentrated largely in Superior and coastal Michigan and high turbidity, phosphorus, and chlorophyll near urban and agricultural areas of Erie. Temporal analysis also showed concurrence of high runoff or precipitation and nitrogen in Lake Michigan offshore of wetlands, suggesting that water quality in these areas is sensitive to changes in climate.

THE NATIONAL COASTAL ASSESSMENT: PARTNERSHIP FOR SUCCESS COASTAL ZONE SYMPOSIUM, CLEVELAND, OH JULY 15-19, 2001

EPA Science Inventory

Partnering for Success (Abstract). Presented at Coastal Zone 01: Hands Across the Water - Linking Land, Lake, and Sea, 15-19 July 2001, Cleveland, OH. 1 p. (ERL,GB R843).

The National Coastal Assessment (Coastal 2000) is a coastal monitoring survey that responds to the ne...

Status and trends in the Lake Superior fish community, 2015

USGS Publications Warehouse

Vinson, Mark; Evrard, Lori M.; Gorman, Owen T.; Yule, Daniel L.

2016-01-01

In 2015, the Lake Superior fish community was sampled with daytime bottom trawls at 76 nearshore and 33 offshore stations. Spring and summer water temperatures in 2015 were colder than average, but warmer than that observed in 2014. In the nearshore zone, a total of 11,882 individuals from 22 species or morphotypes were collected. Nearshore lakewide mean biomass was 1.8 kg/ha, which was near the lowest biomass on record for this survey since it began in 1978. In the offshore zone, a total 12,433 individuals from 8 species or morphotypes were collected lakewide. Offshore lakewide mean biomass was 5.9 kg/ha. The mean of the four previous years was 7.1 kg/ha. The abundance of age-1 Cisco was 14.3 fish/ha which was similar to that measured in 2009. We collected larval Coregonus in surface trawls at 94 locations and estimated a nearshore lakewide average density of 1,459 fish/ha which was nearly twice that measured in 2014.

Status and trends in the Lake Superior fish community, 2014

USGS Publications Warehouse

Vinson, Mark; Evrard, Lori M.; Gorman, Owen T.; Yule, Daniel

2015-01-01

In 2014, the Lake Superior fish community was sampled with daytime bottom trawls at 73 nearshore and 30 offshore stations. Spring and summer water temperatures were the coldest measured for the period of records for the surveys. In the nearshore zone, a total of 15,372 individuals from 28 species or morphotypes were collected. Nearshore lakewide mean biomass was 6.9 kg/ha, which was higher than that observed in the past few years, but below the long-term average of 9.2 kg/ha. In the offshore zone, a total 12,462 individuals from 11 species were collected lakewide. Offshore lakewide mean biomass was 6.6 kg/ha. The mean of the three previous years was 8.6 kg/ha. We collected larval Coregonus in surface trawls at 94 locations and estimated a lakewide average density of 577 fish/ha with a total lakewide population estimate of 14.2 billion (standard error + 30 million).

Can pelagic forage fish and spawning cisco (Coregonus artedi) biomass in the western arm of Lake Superior be assessed with a single summer survey?

USGS Publications Warehouse

Yule, D.L.; Stockwell, J.D.; Schreiner, D.R.; Evrard, L.M.; Balge, M.; Hrabik, T.R.

2009-01-01

Management efforts to rehabilitate lake trout Salvelinus namaycush in Lake Superior have been successful and the recent increase in their numbers has led to interest in measuring biomass of pelagic prey fish species important to these predators. Lake Superior cisco Coregonus artedi currently support roe fisheries and determining the sustainability of these fisheries is an important management issue. We conducted acoustic and midwater trawl surveys of the western arm of Lake Superior during three periods: summer (July-August), October, and November 2006 to determine if a single survey can be timed to estimate biomass of both prey fish and spawning cisco. We evaluated our methods by comparing observed trawl catches of small (<250 mm total length) and large fish to expected trawl catches based on acoustic densities in the trawl path. We found the relationship between observed and expected catches approached unity over a wide range of densities, suggesting that our acoustic method provided reasonable estimates of fish density, and that midwater trawling methods were free of species- and size-selectivity issues. Rainbow smelt Osmerus mordax was by number the most common species captured in the nearshore (<80 m bathymetric depth) stratum during all three surveys, while kiyi Coregonus kiyi was predominant offshore except during November. Total biomass estimates of rainbow smelt in the western arm were similar during all three surveys, while total biomass of kiyi was similar between summer and October, but was lower in November. Total biomass of large cisco increased substantially in November, while small bloater Coregonus hoyi biomass was lower. We compared our summer 2006 estimates of total fish biomass to the results of a summer survey in 1997 and obtained similar results. We conclude that the temporal window for obtaining biomass estimates of pelagic prey species in the western arm of Lake Superior is wide (July through October), but estimating spawning cisco abundance

Relationships between bald eagle productivity and dynamics of fish populations and fisheries in the Wisconsin waters of Lake Superior, 1983-1999

USGS Publications Warehouse

Hoff, Michael H.; Meyer, Michael W.; Van Stappen, Julie; Fratt, Thomas W.

2004-01-01

Bald eagle (Haliaeetus leucocephalus) abundance declined in the 1950s and 1960s along the Wisconsin waters of Lake Superior, and were nearly absent along Wisconsin's Lake Superior shoreline. The population began to increase again between 1980 and 1983, and since then bald eagles nesting on islands along Wisconsin's Lake Superior shoreline (i.e., Apostle Islands) reproduced at a lower rate than have those nesting along the mainland shoreline of the lake and inland. Recent research indicated that bioaccumulation of toxic chemicals in the aquatic food chain no longer limits bald eagle reproduction there, and that productivity at island nests was lower than at mainland nests and inland nests as the result of low food availability. Management agencies have sought models that accurately predict productivity and explain ecological relationships, but no satisfactory models had previously been developed. Modeling was conducted here to determine which factors best explained productivity variability. The Ricker stock-recruitment model derived from only the bivariate breeding pair and productivity data explained only 1% of the variability in productivity data. The functional relationship that explained the greatest amount of productivity variation (83%) included the number of breeding pairs, burbot (Lota lota) biomass, longnose sucker (Catostomus catostomus) biomass, and commercial harvest of nontarget fishes. Model results were interpreted to mean that productivity was positively affected by populations of burbot and longnose sucker, which are important prey items, and by commercial fishermen feeding nontarget fish to bald eagles. Harvest of nontarget fishes by tribal fishermen and burbot and longnose sucker populations have not tended to change during the entire study period, although the burbot population has declined since 1991. Therefore, bald eagle productivity is not predicted to increase unless burbot, longnose sucker, or other preferred prey of bald eagles increases

Drainage network structure and hydrologic behavior of three lake-rich watersheds on the Arctic Coastal Plain, Alaska

USGS Publications Warehouse

Arp, C.D.; Whitman, M.S.; Jones, Benjamin M.; Kemnitz, R.; Grosse, G.; Urban, F.E.

2012-01-01

Watersheds draining the Arctic Coastal Plain (ACP) of Alaska are dominated by permafrost and snowmelt runoff that create abundant surface storage in the form of lakes, wetlands, and beaded streams. These surface water elements compose complex drainage networks that affect aquatic ecosystem connectivity and hydrologic behavior. The 4676 km2 Fish Creek drainage basin is composed of three watersheds that represent a gradient of the ACP landscape with varying extents of eolian, lacustrine, and fluvial landforms. In each watershed, we analyzed 2.5-m-resolution aerial photography, a 5-m digital elevation model, and river gauging and climate records to better understand ACP watershed structure and processes. We show that connected lakes accounted for 19 to 26% of drainage density among watersheds and most all channels initiate from lake basins in the form of beaded streams. Of the > 2500 lakes in these watersheds, 33% have perennial streamflow connectivity, and these represent 66% of total lake area extent. Deeper lakes with over-wintering habitat were more abundant in the watershed with eolian sand deposits, while the watershed with marine silt deposits contained a greater extent of beaded streams and shallow thermokarst lakes that provide essential summer feeding habitat. Comparison of flow regimes among watersheds showed that higher lake extent and lower drained lake-basin extent corresponded with lower snowmelt and higher baseflow runoff. Variation in baseflow runoff among watersheds was most pronounced during drought conditions in 2007 with corresponding reduction in snowmelt peak flows the following year. Comparison with other Arctic watersheds indicates that lake area extent corresponds to slower recession of both snowmelt and baseflow runoff. These analyses help refine our understanding of how Arctic watersheds are structured and function hydrologically, emphasizing the important role of lake basins and suggesting how future lake change may impact hydrologic

Influence of near-surface stratigraphy on coastal landslides at Sleeping Bear Dunes National Lakeshore, Lake Michigan, USA

USGS Publications Warehouse

Barnhardt, W.A.; Jaffe, B.E.; Kayen, R.E.; Cochrane, G.R.

2004-01-01

Lake-level change and landslides are primary controls on the development of coastal environments along the coast of northeastern Lake Michigan. The late Quaternary geology of Sleeping Bear Dunes National Lakeshore was examined with high-resolution seismic reflection profiles, ground-penetrating radar (GPR), and boreholes. Based on sequence-stratigraphic principles, this study recognizes ten stratigraphic units and three major unconformities that were formed by late Pleistocene glaciation and postglacial lake-level changes. Locally high sediment supply, and reworking by two regressions and a transgression have produced a complex stratigraphy that is prone to episodic failure. In 1995, a large landslide deposited approximately 1 million m3 of sediment on the lake floor. The highly deformed landslide deposits, up to 18 m thick, extend 3-4 km offshore and unconformably overlie well-stratified glacial and lacustrine sediment. The landslide-prone bluff is underlain by channel-fill deposits that are oriented nearly perpendicular to the shoreline. The paleochannels are at least 10 m deep and 400 m wide and probably represent stream incision during a lake-level lowstand about 10.3 ka B.P. The channels filled with sediment during the subsequent transgression and lake-level highstand, which climaxed about 4.5 ka B.P. As lake level fell from the highstand, the formation of beach ridges and sand dunes sealed off the channel and isolated a small inland lake (Glen Lake), which lies 5 m above the level of Lake Michigan and may be a source of piped groundwater. Our hypothesis is that the paleochannels act as conduits for pore water flow, and thereby locally reduce soil strength and promote slope failure.

Altitudes between Lake Superior and the Rocky Mountains

USGS Publications Warehouse

Upham, Warren

1891-01-01

In the survey of Lake Agassiz, a preliminary report of which forms Bulletin No. 39, it was found necessary to ascertain the altitudes determined within its area by railroad surveys as the basis for leveling along the shore lines of that glacial lake, and learning their relations in height to each other, to the great lakes of the St. Lawrence and Nelson Rivers, and to the ocean. From the time of the first observations and description of the upper beaches of Lake Agassiz by the author in 1879 and 1881, for the Geological Survey of Minnesota, and especially since the work was extended in 1885, under the U. S. Geological Survey, to include both sides of this lacustrine area in Minnesota and North Dakota now drained by the Red River of the North, much attention has been given to this collection of altitudes, and to the means of referring them to the sea level. The greater part of Lake Agassiz, however, was in Manitoba and adjacent British Territory, stretching north to the Saskatchewan; and in 1887, jointly for the Geological Surveys of the United States and of Canada, the author continued his examination of the beaches and deltas on the west side of the lake along a distance of a hundred miles north from the international boundary, across the prairie region of southwestern Manitoba, the leveling in this work being based on the altitudes of the Canadian Pacific Railway and its branches and connecting railways.

Patterns of organochlorine contamination in lake trout from Wisconsin waters of the Great Lakes

USGS Publications Warehouse

Miller, Michael A.; Madenjian, Charles P.; Masnado, Robert G.

1992-01-01

To investigate spatial and temporal patterns of organochlorine contamination in lake trout from Wisconsin waters of the Great Lakes, we examined laboratory contaminant analysis data of muscle tissue samples from Lake Michigan (n=317) and Lake Superior (n=53) fish. Concentrations of polychlorinated biphenyls (PCBs), chlordane, and dieldrin, reported as mg/kg wet weight in 620 mm to 640 mm mean length Lake Michigan lake trout, decreased over time. Mean total PCB concentration declined exponentially from 9.7 in 1975 to 1.9 in 1990. Total chlordane concentration declined 63 percent from 0.48 in 1983 to 0.18 in 1990, and dieldrin declined 52 percent during this same period, from 0.21 to 0.10. The bioaccumulation rate of PCBs is significantly lower for lake trout inhabiting Lake Michigan's midlake reef complex, compared to lake trout from the nearshore waters of western Lake Michigan. Organochlorine compound concentrations were greater in Lake Michigan lake trout than Lake Superior fish. Lake Superior lean lake trout and siscowet exhibited similar rates of PCB bioaccumulation despite major differneces in muscle tissue lipid content between the two subspecies. The lack of a significant difference in the PCB bioaccumulation rates of lean trout and siscowet suggests that lipid content may not be an important factor influencing PCB bioaccumulation in lake trout, within the range of lipid concentrations observed. Relative concentrations of the various organochlorine contaminants found in lake trout were highly correlated, suggesting similar mass balance processes for these compounds. Evidence presented revealing spatial and temporal patterns of organochlorine contamination may be of value in reestablishing self-sustaining populations of lake trout in Lake Michigan.

Glacial Lake Lind, Wisconsin and Minnesota

USGS Publications Warehouse

Johnson, M.D.; Addis, K.L.; Ferber, L.R.; Hemstad, C.B.; Meyer, G.N.; Komai, L.T.

1999-01-01

Glacial Lake Lind developed in the pre-late Wisconsinan St. Croix River valley, Minnesota and Wisconsin, and lasted more than 1000 yr during the retreat of the Superior lobe at the end of the Wisconsinan glaciation. Lake Lind sediment consists primarily of red varved silt and clay, but also includes mud-flow deposits, nearshore silt (penecontemporaneously deformed in places), nearshore rippled sand, and deltaic sand. Lake Lind varved red clay is not part of glacial Lake Grantsburg, as suggested by earlier authors, because the red varves are separated from overlying glacial Lake Grantsburg silt and clay by a unit of deltaic and fluvial sand. Furthermore, varve correlations indicate that the base of the red varves is younger to the north, showing that the basin expanded as the Superior lobe retreated and was not a lake basin dammed to the southwest by the advancing Grantsburg sublobe. Varve correlations indicate that the Superior lobe retreated at a rate of about 200 m/yr. Uniform winter-clay thickness throughout most of the varve couplets suggests thermal stratification in the lake with clay trapped in the epilimnion; some clay would exit the lake at the outlet prior to winter freeze. Zones of thicker winter-clay layers, in places associated with mud-flow layers, indicate outlet incision, lake-level fall, and shoreline erosion and resuspension of lake clay. The most likely outlet for glacial Lake Lind was in the southwest part of the lake near the present site of Minneapolis, Minnesota. Nearshore sediment indicates that the lake level of glacial Lake Lind was around 280 m. The elevation of the base of the Lake Lind sediments indicates water depth was 20 to 55 m. Evidence in the southern part of the lake basin suggests that the Superior lobe readvanced at least once during the early stages of glacial Lake Lind. Lake Lind ended not by drainage but by being filled in by prograding deltas and outwash plains composed of sand derived from the retreating Superior lobe. It

Lake Superior as seen from Skylab

NASA Image and Video Library

1974-01-06

SL4-139-3953 (7 Jan. 1974) --- An oblique view of a portion of the Middle West looking northeastward toward Lake Superior and Ontario, Canada, as seen from the Skylab space station in Earth orbit. This picture was taken by one of the Skylab 4 crewmen with a hand-held 70mm Hasselblad camera using a 100mm lens. Most of the land mass in the foreground is Wisconsin. Iowa is in the lower left corner. Minnesota is at left and upper left. Ontario is in the far right background. Michigan is at right center. Note the circular-shaped feature at center left which was first observed by the Skylab 4 crewmen. The feature is 85 kilometers (55 miles) in diameter, and it is centered near 91.5 degrees west longitude and 44.5 degrees north latitude. The Mississippi River Valley forms the southwest side of the circular feature. The City of La Crosse, Wisconsin, is just south of the near side of the circle, and the Black River completes the southern and eastern part. The City of Eau Claire is at the north edge of the circle. The most likely origin of circular features of this magnitude are (1) volcanic, (2) structural, or (3) meteorite impact. The feature is not volcanic -- the rocks are the wrong type. Possibly it is structural, formed by slight warping of layered rocks into a basin or dome, followed by erosion of all but the most subtle trace of the structure. The feature could be a severely eroded meteorite impact crater. If so, a thorough study of the area may yield evidence of the extreme pressure and temperature the rocks were subjected to by the shock of an impacting meteorite. Photo credit: NASA

Invasive Ponto-Caspian hydrozoan Cordylophora caspia (hydrozoa: Cnidaria) in southern Baltic coastal lakes

NASA Astrophysics Data System (ADS)

Obolewski, Krystian; Jarosiewicz, Anna; Ożgo, Małgorzata

2015-12-01

Cordylophora caspia Pall. is a highly invasive Ponto-Caspian colonial hydroid with a worldwide distribution. It is a biofouling organism colonizing industrial water installations and causing serious economic problems. Here, we give the first report of its occurrence in southern Baltic coastal lakes, and analyze its distribution in relation to environmental factors and likely colonization routes. Samples were collected from the stalks of Phragmites australis at the total of 102 sites in 15 lakes and lagoons. The species was most numerous in lagoons, i.e. ß-oligohaline water bodies with a surface hydrological connection with the sea, where it reached mean densities of 1200-4800 hydranths m-2. In regression tree analysis, chloride concentration, followed by pH, were the strongest explanatory variables for its occurrence, with highest densities observed at chloride concentration above 1.18 g Cl L-1 and pH 8.05-9.26. At pH 5.77-8.04 higher densities were observed at temperatures above 20.3 °C. Generally, within the range of parameters observed in our study, high densities of C. caspia were associated with high chloride concentration, pH, temperature and electrical conductivity values. The species was also present in freshwater lakes; these colonies may have the highest capacity for future invasions of such habitats. Within lakes, high densities were observed at canals connecting these water bodies with the sea, and at sites close to the inflow of rivers. This distribution pattern can facilitate its further spread into inland waters.

Males exceed females in PCB concentrations of cisco (Coregonus artedi) from Lake Superior

USGS Publications Warehouse

Madenjian, Charles P.; Yule, Daniel L.; Chernyak, Sergei M.; Begnoche, Linda J.; Berglund, Eric K.; Isaac, Edmund J.

2014-01-01

We determined whole-fish polychlorinated biphenyl (PCB) concentrations of 25 male and 25 female age-7 ciscoes (Coregonus artedi) captured from a spawning aggregation in Thunder Bay, Lake Superior, during November 2010. We also determined PCB concentrations in the ovaries and somatic tissue of five additional female ciscoes (ages 5–22). All 55 of these ciscoes were in ripe or nearly ripe condition. Bioenergetics modeling was used to determine the contribution of the growth dilution effect toward a difference in PCB concentrations between the sexes, as females grew substantially faster than males. Results showed that the PCB concentration of males (mean = 141 ng/g) was 43% greater than that of females (mean = 98 ng/g), and this difference was highly significant (P < 0.0001). Mean PCB concentrations in the ovaries and the somatic tissue of the five females were 135 and 100 ng/g, respectively. Based on these PCB determinations for the ovaries and somatic tissue, we concluded that release of eggs by females at previous spawnings was not a contributing factor to the observed difference in PCB concentrations between the sexes. Bioenergetics modeling results indicated that the growth dilution effect could explain males being higher than females in PCB concentration by only 3–7%. We concluded that the higher PCB concentration in males was most likely due to higher rate of energy expenditure, originating from greater activity and a higher resting metabolic rate. Mean PCB concentration in the cisco eggs was well below the U. S. Food and Drug Administration and Ontario Ministry of Environment guidelines of 2000 and 844 ng/g, respectively, and this finding may have implications for the cisco roe fishery currently operating in Lake Superior.

Males exceed females in PCB concentrations of cisco (Coregonus artedi) from Lake Superior.

PubMed

Madenjian, Charles P; Yule, Daniel L; Chernyak, Sergei M; Begnoche, Linda J; Berglund, Eric K; Isaac, Edmund J

2014-09-15

We determined whole-fish polychlorinated biphenyl (PCB) concentrations of 25 male and 25 female age-7 ciscoes (Coregonus artedi) captured from a spawning aggregation in Thunder Bay, Lake Superior, during November 2010. We also determined PCB concentrations in the ovaries and somatic tissue of five additional female ciscoes (ages 5-22). All 55 of these ciscoes were in ripe or nearly ripe condition. Bioenergetics modeling was used to determine the contribution of the growth dilution effect toward a difference in PCB concentrations between the sexes, as females grew substantially faster than males. Results showed that the PCB concentration of males (mean = 141 ng/g) was 43% greater than that of females (mean = 98 ng/g), and this difference was highly significant (P<0.0001). Mean PCB concentrations in the ovaries and the somatic tissue of the five females were 135 and 100 ng/g, respectively. Based on these PCB determinations for the ovaries and somatic tissue, we concluded that release of eggs by females at previous spawnings was not a contributing factor to the observed difference in PCB concentrations between the sexes. Bioenergetics modeling results indicated that the growth dilution effect could explain males being higher than females in PCB concentration by only 3-7%. We concluded that the higher PCB concentration in males was most likely due to higher rate of energy expenditure, originating from greater activity and a higher resting metabolic rate. Mean PCB concentration in the cisco eggs was well below the U. S. Food and Drug Administration and Ontario Ministry of Environment guidelines of 2000 and 844 ng/g, respectively, and this finding may have implications for the cisco roe fishery currently operating in Lake Superior. Published by Elsevier B.V.

Water management sustainability in reclaimed coastal areas. The case of the Massaciuccoli lake basin (Tuscany, Italy)

NASA Astrophysics Data System (ADS)

Rossetto, Rudy; Baneschi, Ilaria; Basile, Paolo; Guidi, Massimo; Pistocchi, Chiara; Sabbatini, Tiziana; Silvestri, Nicola; Bonari, Enrico

2010-05-01

The lake of Massaciuccoli (7 km2 wide and about 2 m deep) and its palustrine nearby areas (about 13 km2 wide) constitute a residual coastal lacustrine and marshy area largerly drained by 1930. In terms of hydrological boundaries, the lake watershed is bordered by carbonate to arenaceous reliefs on the east, by a sandy coastal shallow aquifer on the west (preventing groundwater salinisation), while south and north by the Serchio River and the Burlamacca-Gora di Stiava channels alignment respectively. Since reclamation of the peaty soils started, subsidence began (2 to 3 m in 70 years), leaving the lake perched and central respect the low drained area, now 0 to -3 m below m.s.l., and requiring 16 km embankment construction. During the dry summer season, the lake undergoes a severe water stress, that, along with nutrients input, causes the continuous ecosystem degradation resulting in water salinisation and eutrophication. Water stress results in a head decrease below m.s.l., causing seawater intrusion along the main outlet, and reaching its highest point at the end of the summer season (common head values between -0.40 and -0.5 a.m.s.l.). The water budget for an average dry season lasting about 100 days was computed, considering a 10% error, in order to understand and evaluate all the components leading to the above mentioned water stress by means of several multidisciplinary activities during the years 2008-2009. They started with a thoroughly literature review, continued with hydrological, hydrogeochemical monitoring and testing (both for surface water and the shallow aquifer) and agronomical investigations (to characterize cropping systems, evapotranspiration rates and irrigation schemes). All the collected data were then processed by means of statistical methods, time series analysis, numerical modelling of the shallow aquifer and hydrological modelling. The results demonstrate the presence of two interrelated hydrological sub-systems: the lake and the reclaimed

Biological consequences of the coaster brook trout restoration stocking program in Lake Superior tributaries with Pictured Rocks National Lakeshore

USGS Publications Warehouse

Leonard, Jill B.K.; Stott, Wendylee; Loope, Delora M.; Kusnierz, Paul C.; Sreenivasan, Ashwin

2013-01-01

The coaster Brook Trout Salvelinus fontinalis is a Lake Superior ecotype representing intraspecific variation that has been impacted by habitat loss and overfishing. Hatchery strains of Brook Trout derived from populations in Lake Superior were stocked into streams within Pictured Rocks National Lakeshore, Michigan, as part of an effort to rehabilitate adfluvial coaster Brook Trout. Wild and hatchery Brook Trout from three streams (Mosquito River, Hurricane River, and Sevenmile Creek) were examined for movement behavior, size, physiology, and reproductive success. Behavior and size of the stocked fish were similar to those of wild fish, and less than 15% of the stocked, tagged Brook Trout emigrated from the river into which they were stocked. There was little evidence of successful reproduction by stocked Brook Trout. Similar to the results of other studies, our findings suggest that the stocking of nonlocal Brook Trout strains where a local population already exists results in limited natural reproduction and should be avoided, particularly if the mechanisms governing the ecotype of interest are poorly understood.

Can a rapid underwater video approach enhance the benthic assessment capability of the National Coastal Condition Assessmentin the Great Lakes?

EPA Science Inventory

In the U.S. National Coastal Condition Assessment (NCCA) field survey in summer 2010, over 400 sites in the nearshore zone of the U.S. Great Lakes were sampled. As a supplement to core NCCA benthic taxonomy and sediment chemistry, underwater video images of the bottom condition ...

The Location of Lake Titicaca's Coastal Area During the Tiwanaku and Inca Periods: Methodology and Strategies of Underwater Archaeology

NASA Astrophysics Data System (ADS)

Delaere, Christophe

2017-12-01

For more than 30 years, numerous research projects have revealed the dense and complex human settlement of the lacustrine basin of Lake Titicaca in Bolivia and Peru. Physical evidence of such establishments has been discovered in plains, valleys, and highlands connected to the lake. These remains confirm human occupation and development in this environment, particularly during the Tiwanaku (AD 500-1150) and Inca (AD 1400-1532) Periods. The research project discussed in this paper includes consideration of submerged areas through underwater archaeology. This investigation involves analysis of two areas that have evidence of ancient human occupation but are poorly documented: the coastal and lacustrine regions. Due to its dominance in the landscape, Lake Titicaca has always been a major feature in the life and identity of populations of this vicinity. These inhabitants have developed socio-economic and ritual behaviours directly associated with the lake that have left cultural and material prints that are the foci of the present study.

Challenges to the Lake

EPA Science Inventory

During the past decade we have extensively studied coastal ecosystems in the Great Lakes. Some research efforts have linked coastal receiving systems to conditions in their contributing watersheds; others have focused on developing invasive species detection and monitoring strat...

Habitat and diet differentiation by two strains of rainbow trout in Lake Superior based on archival tags, stable isotopes, and bioenergetics

EPA Science Inventory

Two strains of potamodromous rainbow trout Oncorhynchus mykiss in the Minnesota waters of Lake Superior exhibited differences in behavior and temperature tolerance at egg and fry stages, but the extent of these differences was not well understood in adult fish. To gain a better u...

No Small Matter? An Increase of 30 Trillion Amphipods (plus or minus a few) in Lake Superior between 1973 and 2005

EPA Science Inventory

We compared a lakewide biological sampling in 2005 with the other lakewide biological sampling of Lake Superior in 1973...Lakewide, there were 40 trillion Diporeia in 2005, an increase of approx. 30 trillion compared with 1973. The open questions: what caused this apparen...

Vertical distribution of fish biomass in Lake Superior: Implications for day bottom trawl surveys

USGS Publications Warehouse

Stockwell, J.D.; Yule, D.L.; Hrabik, T.R.; Adams, J.V.; Gorman, O.T.; Holbrook, B.V.

2007-01-01

Evaluation of the biases in sampling methodology is essential for understanding the limitations of abundance and biomass estimates of fish populations. Estimates from surveys that rely solely on bottom trawls may be particularly vulnerable to bias if pelagic fish are numerous. We evaluated the variability in the vertical distribution of fish biomass during the U.S. Geological Survey's annual spring bottom trawl survey of Lake Superior using concurrent hydroacoustic observations to (1) test the assumption that fish are generally demersal during the day and (2) evaluate the potential for predictive models to improve bottom trawl–determined biomass estimates. Our results indicate that the assumption that fish exhibit demersal behavior during the annual spring bottom trawl survey in Lake Superior is unfounded. Bottom trawl biomass (BBT) estimates (mean ± SE) for species known to exhibit pelagic behavior (cisco Coregonus artedi, bloater C. hoyi, kiyi C. kiyi, and rainbow smelt Osmerus mordax; 3.01 ± 0.73 kg/ha) were not significantly greater than mean acoustic pelagic zone biomass (BAPZ) estimates (6.39 ± 2.03 kg/ha). Mean BAPZ estimates were 1.6- to 4.8-fold greater than mean BBT estimates over 4 years of sampling. The relationship between concurrent BAPZ and BBT estimates was marginally significant and highly variable. Predicted BAPZ estimates using cross-validation models were sensitive to adjustments for back-transforming from the logarithmic to the linear scale and poorly corresponded to observed BAPZ estimates. We conclude that statistical models to predict BAPZ from day BBT cannot be developed. We propose that night sampling with multiple gears will be necessary to generate better biomass estimates for management needs.

2009 Spawning cisco investigations in the Canadian waters of Lake Superior

USGS Publications Warehouse

Yule, Daniel L.; Cholwek, Gary A.; Evrard, Lori M.; E. Berglund,; K.I. Cullis,

2010-01-01

We sampled with acoustics (AC) and midwater trawls (MT) to determine cisco abundance in Lake Superior’s Thunder and Black bays during 8-14 November, 2009. Total abundance of spawning-size (≥ 250 mm total length) ciscoes was estimated at 6.25 million in Thunder Bay and 1.12 million in Black Bay. Exploitation fractions of market-size (≥ age 6) females from Thunder and Black bays for 2009 were estimated at 7.1% and 11.3%, respectively; below the recommended maximum annual harvest of 15% recently adopted by Lake Superior fisheries managers. Given Thunder Bay spawner densities are on a downward trajectory, and recruitment since the 2003 year-class has been low, it is likely the exploitation fractions will increase in the future. After 2010, the Ontario Ministry of Natural Resources (OMNR) will carry on the AC program as a management activity. It is likely suspended experimental gill net (GN) samples will be used to ground truth future AC samples. In 2009, we characterized the length and age structure of Thunder Bay ciscoes using both MT samples and GN samples. Females represented 49% of the MT catch, but only 39% in GN samples. Catching a smaller proportion of females in GN samples resulted in a lower female population estimate and a higher estimated exploitation fraction (10.4%) compared to MT samples (7.1%). Experimental gill net effort was limited to 10-11.8 m water column depths where midwater trawl samples also caught roughly 40% females. Ciscoes ≥ age 17 (≥ 1992 year class) were common in Black Bay, but rare in Thunder Bay suggesting: 1) the stocks may be distinct; and 2) total mortality of ciscoes returning to spawn in Black Bay in recent years has been lower than ciscoes returning to Thunder Bay. Our mid-November 2009 effort to assess the Black Bay stock by sampling outside of the 3 bay in the lake proper was deemed successful, but this should be confirmed by sampling the Black Bay region during both mid- and late-November 2010.

2008 Spawning Cisco Investigations in the Canadian Waters of Lake Superior

USGS Publications Warehouse

Yule, Daniel; Addison, Peter A.; Evrard, Lori M.; Cullis, Ken I.; Cholwek, Gary A.

2009-01-01

The Great Lakes Science Center of the United States Geological Survey (USGS) is working cooperatively with the Ontario Ministry of Natural Resources (OMNR) on a threeyear study to develop standard procedures for acoustic and midwater trawl (AC-MT) assessments of spawning cisco Coregonus artedi that the OMNR can carry forward as a management activity. In year two (2008), we conducted an AC-MT survey of the northern shore from Nipigon Bay to Thunder Bay. Spawning-cisco (> 250 mm total length) densities were lowest near Nipigon Bay (<10/ha), moderate in and around Black Bay (15- 30/ha), and highest in Thunder Bay (118/ha). Rainbow smelt Osmerus mordax densities were highest in Nipigon (2,179/ha) and Black (3,219/ha) bays, and lowest in Thunder Bay (961/ha). We combined our AC-MT survey results with commercial catch records to estimate exploitation fractions of female cisco in Thunder Bay during the 2008 fishery at 4% for ages 1-5, 8.7% for ages 6-12, and 4.4% for ages ≥ 13. Lake Superior fishery managers recently recommended that annual exploitation of adult female lake cisco be kept below 10-15%. Recruitment of cisco since 2003 has been low and there is a strong probability the Thunder Bay stock will decline into the future. Using a simple population dynamics approach we estimated that if the current total allowable catch (TAC) quota is held constant, exploitation fractions could exceed 10% by 2010 and 15% by 2011. Our 2008 collections suggested the survey of Black Bay was likely conducted before all spawners had returned there to spawn. Our data also suggested that cisco collected in Black Bay and east of this site in mid-November may be from the same stock. During November 2009 we will attempt to get better definition of the area occupied by cisco around Black Bay and also determine when surveys should be conducted at this location.

Status and trends in the Lake Superior fish community, 2016

USGS Publications Warehouse

Vinson, Mark; Evrard, Lori M.; Gorman, Owen T.; Yule, Daniel

2017-01-01

In 2016, the Lake Superior fish community was sampled with daytime bottom trawls at 76 nearshore and 35 offshore stations. Spring and summer water temperatures in 2016 were warmer than average and considerably warmer than observed in 2014 and 2015. In the nearshore zone, a total of 17,449 individuals from 20 species or morphotypes were collected. Nearshore lakewide mean biomass was 2.2 kg/ha, which was near the lowest biomass on record for this survey since it began in 1978. In the offshore zone, a total 8,487 individuals from 16 species or morphotypes were collected lakewide. Offshore lakewide mean biomass was 4.5 kg/ha, which was the lowest biomass recorded since the offshore survey began in 2011. The density of age-1 Cisco was 5.0 fish/ha, which was 35% of that measured in 2015. Larval Coregonus were collected in surface trawls at 144 locations lakewide from May to July. The average nearshore lakewide larval Coregonus density estimate was 1,630 fish/ha, which was similar to that estimated in 2015.

National Coastal Condition Assessment Report 2010

EPA Science Inventory

This National Coastal Condition Assessment 2010 (NCCA 2010) is the fifth in a series of reports assessing the condition of the coastal waters of the United States, including a vast array of estuarine, Great Lakes, and coastal embayment waters. It is part of the National Aquatic R...

EXOTIC AND INVASIVE AQUATIC PLANTS IN GREAT LAKES COASTAL WETLANDS: DISTRIBUTION AND RELATION TO WATERSHED LAND USE AND PLANT RICHNESS AND COVER

EPA Science Inventory

This manuscript provides previously unavailable information to researchers and managers concerning exotic plants in the Great Lakes...This work arises out of our broader efforts to describe biota - habitat relationships in coastal wetlands, and as such falls under Aquatic Stresso...

Analysis of suspended solids by single-particle scattering. [for Lake Superior pollution monitoring

NASA Technical Reports Server (NTRS)

Diehl, S. R.; Smith, D. T.; Sydor, M.

1979-01-01

Light scattering by individual particulates is used in a multiple-detector system to categorize the composition of suspended solids in terms of broad particulate categories. The scattering signatures of red clay and taconite tailings, the two primary particulate contaminants in western Lake Superior, along with two types of asbestiform fibers, amphibole and chrysolite, were studied in detail. A method was developed to predict the concentration of asbestiform fibers in filtration plant samples for which electron microscope analysis was done concurrently. Fiber levels as low as 50,000 fibers/liter were optically detectable. The method has application in optical categorization of samples for remote sensing purposes and offers a fast, inexpensive means for analyzing water samples from filtration plants for specific particulate contaminants.

Feasibility Study of Shoreline Protection and Lake Level Regulation for Lake Ontario. Reconnaissance Report. Volume II. Appendices.

DTIC Science & Technology

1981-11-01

Presque Isle , Pennsylvania , Lake Erie . For more information on headlands see Coastal Enqineering, 2, Sedimentation, Estuaries, Tides, Effluents, and...Environmental Inventory. 1978. Erie County Metropolitan Planning Commission. Erie County Land Use Plan, Erie County, Pennsylvania . 1971. Geis, James W...International Lake Erie Regulation Study A-I-13 e. New York State Coastal Zone Management Program A-1-14 f. Pollution from Land Use Activities (PLUARG) A-1-14

Densities and Diel Vertical Migration of Mysis relicta in Lake Superior: A Comparison of Optical Plankton Encounter and Net-based Approaches

EPA Science Inventory

In this study, we used data from an OPC, and LOPC, and vertical net tows to estimate densities and describe the day/night vertical distribution of Mysis at a series of stations distributed throughout Lake Superior, and to evaluate the efficacy of using (L)OPC for examining DVM of...

EPA's National Coastal Condition Assessment: Pilot research ...

EPA Pesticide Factsheets

The EPA Office of Water’s 5-year cycles of national surveys of wetlands, lakes, rivers, and coastal areas help satisfy the assessment and antidegradation provisions of the Clean Water Act. Measuring extant conditions precedes measuring change in conditions. Surveys are challenged to adequately sample extreme conditions occurring in small areas. Extremely bad conditions are targets for remediation. Extremely good conditions are targets for protection. In 2010, the National Coastal Condition Assessment (NCCA) found the majority of the coastal Great Lakes (by area) was in good condition for water (60%) and sediment (51%) quality but not benthos (20%) and fish tissue contaminants (<1%). Low sampling success for biological sampling was an issue. As part of the 2014 Lake Erie CSMI field year, EPA’s Great Lakes National Program Office, working with the Office of Research and Development, began pilot research to integrate connecting channels into Great Lakes surveys. Assessments of the Huron-Erie corridor (HEC; 2014, 2015) and St Marys River (SMR; 2015, 2016) which have previously gone unassessed by NCCA, are being developed. Water, sediment, and benthic quality data from the 2014 HEC survey (n=60) were compared to 2010 NCCA data from adjacent lakes. Water quality rated “poor” (as % area) in HEC was intermediate compared to Lake Huron and Erie regardless of which lake-specific thresholds were used. However, the amount of area classified as “good” was highl

(90)Sr in fish from the southern Baltic Sea, coastal lagoons and freshwater lake.

PubMed

Zalewska, Tamara; Saniewski, Michał; Suplińska, Maria; Rubel, Barbara

2016-07-01

Activity concentrations of radioactive (90)Sr were studied in four fish species: herring, flounder, sprat and cod caught in the southern Baltic Sea in two periods: 2005-2009 and 2013-2014. The study included also perch from the coastal lagoons - Vistula Lagoon and Szczcin Lagoon and a freshwater lake - Żarnowieckie Lake as well as additional lake species: pike and bream. (90)Sr activity concentrations were compared in relation to species and to particular tissue: muscle, whole fish (eviscerated) and bones. In 2014, in the Baltic, the maximal (90)Sr concentrations were found in fishbones: herring - 0.39 Bq kg(-1) w.w., cod - 0.48 Bq kg(-1) w.w., and flounder - 0.54 Bq kg(-1) w.w. In the whole fish the maximal concentrations were found in flounder - 0.16 Bq kg(-1) w.w. and cod - 0.15 Bq kg(-1) w.w., while in herring - 0.022 Bq kg(-1) w.w. and sprat - 0.026 Bq kg(-1) w.w. they stayed at lower level. Relatively high (90)Sr concentrations were detected in whole fish from freshwater Lake Żarnowieckie: perch - 0.054 Bq kg(-1) w.w., pike - 0.062 Bq kg(-1) w.w. and bream - 0.140 Bq kg(-1) w.w. Concentration ratio (CR) determined for particular fish tissues and for whole eviscerated fish in relation to (90)Sr concentrations in seawater and lake water were showing significant variability unlike the corresponding (137)Cs concentration ratios which are stable and specific for fish species. The study corroborates with the conviction of the growing role of (90)Sr in the overall radioactivity in the southern Baltic Sea as compared to (137)Cs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Status of Lake Superior’s lower trophic levels

EPA Science Inventory

To meet the Fish Community Objectives set for Lake Superior by the Great Lakes Fishery Commission, a key factor is the condition of the lower food web that supports productivity of fisheries. To assess the condition of lower trophic levels and inform the Lake Superior Technical C...

Perchlorate in the Great Lakes: isotopic composition and origin.

PubMed

Poghosyan, Armen; Sturchio, Neil C; Morrison, Candice G; Beloso, Abelardo D; Guan, Yunbin; Eiler, John M; Jackson, W Andrew; Hatzinger, Paul B

2014-10-07

Perchlorate is a persistent and mobile contaminant in the environment with both natural and anthropogenic sources. Stable isotope ratios of oxygen (δ(18)O, Δ(17)O) and chlorine (δ(37)Cl) along with the abundance of the radioactive isotope (36)Cl were used to trace perchlorate sources and behavior in the Laurentian Great Lakes. These lakes were selected for study as a likely repository of recent atmospheric perchlorate deposition. Perchlorate concentrations in the Great Lakes range from 0.05 to 0.13 μg per liter. δ(37)Cl values of perchlorate from the Great Lakes range from +3.0‰ (Lake Ontario) to +4.0‰ (Lake Superior), whereas δ(18)O values range from -4.1‰ (Lake Superior) to +4.0‰ (Lake Erie). Great Lakes perchlorate has mass-independent oxygen isotopic variations with positive Δ(17)O values (+1.6‰ to +2.7‰) divided into two distinct groups: Lake Superior (+2.7‰) and the other four lakes (∼+1.7‰). The stable isotopic results indicate that perchlorate in the Great Lakes is dominantly of natural origin, having isotopic composition resembling that measured for indigenous perchlorate from preindustrial groundwaters of the western USA. The (36)Cl/Cl ratio of perchlorate varies widely from 7.4 × 10(-12) (Lake Ontario) to 6.7 × 10(-11) (Lake Superior). These (36)ClO4(-) abundances are consistent with an atmospheric origin of perchlorate in the Great Lakes. The relatively high (36)ClO4(-) abundances in the larger lakes (Lakes Superior and Michigan) could be explained by the presence of (36)Cl-enriched perchlorate deposited during the period of elevated atmospheric (36)Cl activity following thermonuclear bomb tests in the Pacific Ocean.

Micrometeorological Measurement of Fetch- and Atmospheric Stability-Dependent Air- Water Exchange of Legacy Semivolatile Organic Contaminants in Lake Superior

NASA Astrophysics Data System (ADS)

Perlinger, J. A.; Tobias, D. E.; Rowe, M. D.

2008-12-01

Coastal waters including the Laurentian Great Lakes are particularly susceptible to local, regional, and long- range transport and deposition of semivolatile organic contaminants (SOCs) as gases and/or associated with particles. Recently-marketed SOCs can be expected to undergo net deposition in surface waters, whereas legacy SOCs such as polychlorinated biphenyls (PCBs) are likely to be at equilibrium with respect to air-water exchange, or, if atmospheric concentrations decrease through, e.g., policy implementation, to undergo net gas emission. SOC air-water exchange flux is usually estimated using the two-film model. This model describes molecular diffusion through the air and water films adjacent to the air-water interface. Air-water exchange flux is estimated as the product of SOC fugacity, typically based on on-shore gaseous concentration measurements, and a transfer coefficient, the latter which is estimated from SOC properties and environmental conditions. The transfer coefficient formulation commonly applied neglects resistance to exchange in the internal boundary layer under atmospherically stable conditions, and the use of on-shore gaseous concentration neglects fetch-dependent equilibration, both of which will tend to cause overestimation of flux magnitude. Thus, for legacy chemicals or in any highly contaminated surface water, the rate at which the water is cleansed through gas emission tends to be over-predicted using this approach. Micrometeorological measurement of air-water exchange rates of legacy SOCs was carried out on ships during four transect experiments during off-shore flow in Lake Superior using novel multicapillary collection devices and thermal extraction technology to measure parts-per-quadrillion SOC levels. Employing sensible heat in the modified Bowen ratio, fluxes at three over-water stations along the transects were measured, along with up-wind, onshore gaseous concentration and aqueous concentration. The atmosphere was unstable for

First record of trypanosomes from the blood of sculpins (Cottus ricei and C. cognatus) from Lake Superior, WI, USA

USGS Publications Warehouse

Pronina, Svetlana V.; Pronin, Nikolai M.; Selgeby, Jim H.

1999-01-01

During parasitological research of fishes in Lake Superior (USA) in August-September 1994, infection with trypanosomes of the blood of sculpins (Cottus ricei and C. cognatus) was recorded for the first time. The descriptions of three morphological groups of the genus Trypanosoma: T. sp. I, found in blood of C. ricei, T. sp. II and T. sp. III from blood of C. cognatus, have been provided.

COSEE Superior Creates Passion for Science

EPA Science Inventory

COSEE was a transformative educational experience that has changed the way I teach. In July, I participated in the COSEE Lake Superior Shipboard and Shoreline Science program. I spent a week on the US EPA’s R/V Lake Guardian with 14 other teachers and a crew of sailors and scient...

Patterns and controls of mercury accumulation in sediments from three thermokarst lakes on the Arctic Coastal Plain of Alaska

USGS Publications Warehouse

Burke, Samantha M.; Zimmerman, Christian E.; Branfireun, Brian A.; Koch, Joshua C.; Swanson, Heidi K.

2018-01-01

The biogeochemical cycle of mercury will be influenced by climate change, particularly at higher latitudes. Investigations of historical mercury accumulation in lake sediments inform future predictions as to how climate change might affect mercury biogeochemistry; however, in regions with a paucity of data, such as the thermokarst-rich Arctic Coastal Plain of Alaska (ACP), the trajectory of mercury accumulation in lake sediments is particularly uncertain. Sediment cores from three thermokarst lakes on the ACP were analyzed to understand changes in, and drivers of, Hg accumulation over the past ~ 100 years. Mercury accumulation in two of the three lakes was variable and high over the past century (91.96 and 78.6 µg/m2/year), and largely controlled by sedimentation rate. Mercury accumulation in the third lake was lower (14.2 µg/m2/year), more temporally uniform, and was more strongly related to sediment Hg concentration than sedimentation rate. Sediment mercury concentrations were quantitatively related to measures of sediment composition and VRS-inferred chlorophyll a, and sedimentation rates were related to various catchment characteristics. These results were compared to data from 37 previously studied Arctic and Alaskan lakes. Results from the meta-analysis indicate that thermokarst lakes have significantly higher and more variable Hg accumulation rates than non-thermokarst lakes, suggesting that certain properties (e.g., thermal erosion, thaw slumping, low hydraulic conductivity) likely make lakes prone to high and variable Hg accumulation rates. Differences and high variability in Hg accumulation among high latitude lakes highlight the complexity of predicting future climate-related change impacts on mercury cycling in these environments.

DETERMINING THE INFLUENCE OF LANDSCAPE AND RESEARCH-SPECIFIC HABITAT VARIABLES ON VARIATION OF THERMAL CHARACTERISTICS OF STREAMS WITHIN WESTERN LAKE SUPERIOR WATERSHEDS

EPA Science Inventory

As part of a study to develop and test a framework for predicting sensitivity of watersheds to land-use activities, temperatures were monitored in 48 second- and third- order streams on the north and south shores of western Lake Superior. Maximun 21-day average temperatures, whic...

Population structure of an invasive parthenogenetic gastropod in coastal lakes and estuaries of northern KwaZulu-Natal, South Africa.

PubMed

Miranda, Nelson A F; Perissinotto, Renzo; Appleton, Christopher C

2011-01-01

Estuaries and coastal lakes receive little attention despite being heavily invaded by non-indigenous invasive species (NIS). In these situations, studies of population dynamics in invaded habitats can provide valuable insights into how NIS interact with new environments. Tarebia granifera is a prosobranch gastropod from south-east Asia which has invaded other sub-tropical parts of the world. This study addresses whether a small number of key environmental factors influences gastropod communities, and specifically how the population density and size structure of T. granifera were influenced by environmental change in estuaries and coastal lakes in southern Africa. T. granifera's density, number of brooded juveniles and size structure were measured at the St. Lucia Estuary, Mgobozeleni Estuary, Lake Sibaya and Lake Nhlange. Size structure was classified according to shell height (SH). All dissected individuals were found to be female and free from trematode infection. Salinity, water depth, temperature, and pH were the main factors correlated with population density of gastropod communities. T. granifera often reached densities well over 1000 ind. m(-2), displacing indigenous gastropods and becoming a dominant component of the benthic community. T. granifera successfully invaded estuaries despite frequent exposure to high salinity and desiccation, which could together eliminate >97% of the population. The persistence of T. granifera was ensured due to its high fecundity and the environmental tolerance of large adults (20-30 mm SH) which carried an average of 158±12.8 SD brooded juveniles. Repeat introductions were not essential for the success of this parthenogenetic NIS. There is a need for a broader study on the reproductive biology of T. granifera (including the previously overlooked "brood pouch ecology"), which affects population dynamics and may be relevant to other parthenogenetic NIS, such as Melanoides tuberculata and Potamopyrgus antipodarum.

NATIONAL COASTAL CONDITION REPORT IV

EPA Science Inventory

The National Coastal Condition Report IV (NCCR IV) is the fourth in a series of environmental assessments of U.S. coastal waters and the Great Lakes. The report includes assessments of all the nation’s estuaries in the contiguous 48 states and Puerto Rico, south-eastern Alaska, ...

Geomicrobiology of Fe-rich crusts in Lake Superior sediment

NASA Astrophysics Data System (ADS)

Dittrich, M.; Monreau, L.; Quazi, S.; Raoof, B.; Chesnyuk, A.; Katsev, S.; Fulthorpe, R.

2012-04-01

The limnological puzzles of Lake Superior are increasingly attracting scientists, and very little is known about the sediments and their associated microflora. The sediments are organic poor (less than 5%C) and the lake is deep oligotrophic, with water temperatures at the bottom around 3C. Previous studies reveal Fe-rich layers in the sediments at multiple loccations around the lake. The origin and mechanisms of formation of this layer remain unknown. In this study we investigated geochemical and microbiological processes that may lead to the formation of a two cm thick iron layer about 10 cm below the sediment surface. Sediment cores from two stations (EM, 230m water depth and ED, 310m water depth) in the East Basin were used. We monitored oxygen and pH depth profiles with microsensors, porewater and sediment solid matter were analyzed for nutrient and metal contents. Furthermore, phosphorus and iron sequantial extractions of sediment cores have been perfomed. The total cell count was determined using DAPI epifluoresence microscopy. DNA was extracted from the sediment samples and 16S ribosonal RNA amplicons were analyzed with denaturing gradient gel electrophoresis (DGGE). For a more in depth analysis, DNA samples from 8-10 cm and 10-12 cm were sent to the Research and Testing Lab (Texas) for pyrosequencing of 16S rRNA gene amplicons amplified using barcoded universal primers 27f-519r. The scanning electron microscope (SEM) images from the iron layer 10-12cm show filaments that were encrusted with spheres ca. 20 nm in diameter. SEM observations of thin sections also indicate the presence of very fine particles showing various morphologies. Analyses of the deposit material by SEM and energy dispersive X-ray spectroscopy (EDS) indicate that bacteria cells surfaces served as nucleation surfaces for Fe-oxide formation. EDS line-scans through bacterial cells covered with precipitates reveal phosphorus and carbon peaks at interface between cell surface and Fe

Pleistocene Lake Bonneville as an analog for extraterrestrial lakes and oceans: Chapter 21

USGS Publications Warehouse

Chan, M.A.; Jewell, P.; Parker, T.J.; Ormo, J.; Okubo, Chris; Komatsu, G.

2016-01-01

Geomorphic confirmation for a putative ancient Mars ocean relies on analog comparisons of coastal-like features such as shoreline feature attributes and temporal scales of process formation. Pleistocene Lake Bonneville is one of the few large, geologically young, terrestrial lake systems that exemplify well-preserved shoreline characteristics that formed quickly, on the order of a thousand years or less. Studies of Lake Bonneville provide two essential analog considerations for interpreting shorelines on Mars: (1) morphological variations in expression depend on constructional vs erosional processes, and (2) shorelines are not always correlative at an equipotential elevation across a basin due to isostasy, heat flow, wave setup, fetch, and other factors. Although other large terrestrial lake systems display supporting evidence for geomorphic comparisons, Lake Bonneville encompasses the most integrated examples of preserved coastal features related to basin history, sediment supply, climate, and fetch, all within the context of a detailed hydrograph. These collective terrestrial lessons provide a framework to evaluate possible boundary conditions for ancient Mars hydrology and large water body environmental feedbacks. This knowledge of shoreline characteristics, processes, and environments can support explorations of habitable environments and guide future mission explorations.

The Photodegradation of Ibuprofen and Dissolved Organic Matter in Lake Superior and St. Louis River Water

PubMed Central

Moynan, Angela B.

2012-01-01

Abstract Ibuprofen can enter bodies of water via waste water treatment. The question was what effect does photodegradation have on ibuprofen and dissolved organic matter (DOM) in Lake Superior (oligiotrophic) and St. Louis (tannic stained) River water? Ibuprofen concentrations of 15,000, 30,000, and 60,000 μg/L were made from lake, river, and distilled water, as well as additional distilled concentrations of 7,500 and 120,000 μg/L. Half of the eighty-four trial cups were placed in an ultraviolet light cabinet and half of the set were placed in a dark cabinet for three days. After the exposure period, a UV-Vis was performed to measure change in molar mass and the summed absorbance of colored dissolved organic matter (CDOM). It appears that ibuprofen decreases in molar mass after exposure to light in distilled and lake water with 15,000 μg/L of ibuprofen. Surprisingly, the molar mass of DOM in river water increases after UV exposure. Possibly, this occurred because the river water has such a high molar mass of DOM and was not filtered. Microbial biomass could also have contributed to this increase. Ibuprofen entering bodies of water via the waste water treatment system appears to be affected by UV light exposure, but in different ways. PMID:23244688

Quantitative remote sensing study indicates doubling of coastal erosion rate in past 50 yr along a segment of the Arctic coast of Alaska

USGS Publications Warehouse

Mars, J.C.; Houseknecht, D.W.

2007-01-01

A new quantitative coastal land gained-and-lost method uses image analysis of topographic maps and Landsat thematic mapper short-wave infrared data to document accelerated coastal land loss and thermokarst lake expansion and drainage. The data span 1955-2005 along the Beaufort Sea coast north of Teshekpuk Lake in the National Petroleum Reserve in Alaska. Some areas have undergone as much as 0.9 km of coastal erosion in the past 50 yr. Land loss attributed to coastal erosion more than doubled, from 0.48 km2 yr-1 during 1955-1985 to 1.08 km2 yr-1 during 1985-2005. Coastal erosion has breached thermokarst lakes, causing initial draining of the lakes followed by marine floodng. Although inland thermokarst lakes show some uniform expansion, lakes breached by coastal erosion display lake expansion several orders of magnitude greater than inland lakes. ?? 2007 The Geological Society of America.

The Hardwood Gneiss: Evidence for high P-T Archean metamorphism in the southern province of the Lake Superior region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peterson, J.W.; Geiger, C.A.

1990-03-01

The Hardwood Gneiss is an areally small unit of Precambrian granulite-grade rocks exposed in the Archean gneiss terrane of the southern Lake Superior region. The rocks are located in the southwestern portion of the Upper Peninsula of Michigan and consist of a structurally conformable package of quartzitic, metapelitic, amphibolitic, and metabasic units. Three texturally distinct garnet types are present in the metabasites and are interpreted to represent two metamorphic events. Geothermobarometry indicates conditions of {approximately}8.2-11.6 kbar and {approximately}770C for M1, and conditions of {approximately}6.0-10.1 kbar and {approximately}610-740C for M2. It is proposed that M1 was Archean and contemporaneous with amore » high-grade metamorphic event recorded in the Minnesota River Valley. The M2 event was probably Early Proterozoic and pre-Penokean, with metamorphic conditions more intense than those generally ascribed to the Penokean Orogeny in Michigan, but similar to the conditions reported for the Kapuskasing zone of Ontario. The high paleopressures and temperatures of the M1 event make the Hardwood Gneiss distinct from any rocks previously described in the southern Lake Superior region, and suggest intense tectonic activity during the Archean.« less

The mesoproterozoic midcontinent rift system, Lake Superior region, USA

USGS Publications Warehouse

Ojakangas, R.W.; Morey, G.B.; Green, J.C.

2001-01-01

Exposures in the Lake Superior region, and associated geophysical evidence, show that a 2000 km-long rift system developed within the North American craton ??? 1109-1087 Ma, the age span of the most of the volcanic rocks. This system is characterized by immense volumes of mafic igneous rocks, mostly subaerial plateau basalts, generated in two major pulses largely by a hot mantle plume. A new ocean basin was nearly formed before rifting ceased, perhaps due to the remote effect of the Grenville continental collision to the east. Broad sagging/subsidence, combined with a system of axial half-grabens separated along the length of the rift by accommodation zones, provided conditions for the accumulation of as much as 20 km of volcanic rocks and as much as 10 km of post-rift clastic sediments, both along the rift axis and in basins flanking a central, post-volcanic horst. Pre-rift mature, quartzose sandstones imply little or no uplift prior to the onset of rift volcanism. Early post-rift red-bed sediments consist almost entirely of intrabasinally derived volcanic sediment deposited in alluvial fan to fluvial settings; the exception is one gray to black carbon-bearing lacustrine(?) unit. This early sedimentation phase was followed by broad crustal sagging and deposition of progressively more mature red-bed, fluvial sediments with an extra-basinal provenance. ?? 2001 Elsevier Science B.V. All rights reserved.

REDUCING EXPOSURE UNCERTAINTY FOR ASSESSMENT OF DIOXIN TOXICITY RISKS TO LAKE TROUT POPULATIONS IN THE GREAT LAKES

EPA Science Inventory

During the 20th century, declines of lake trout (Salvelinus namaycush) populations to virtual extinction in all the Great Lakes except Lake Superior were followed by failure of stocked lake trout to achieve recruitment through natural reproduction. Stresses such as excessive harv...

National Coastal Condition Report III Factsheet

EPA Pesticide Factsheets

The National Coastal Condition Report III (NCCR III) is the third in a series of environmental assessments of U.S. coastal waters and the Great Lakes. The report includes assessments of the nation’s estuaries in the contiguous 48 states and Puerto Rico.

National Coastal Condition Report III (2008)

EPA Pesticide Factsheets

The National Coastal Condition Report III (NCCR III) is the third in a series of environmental assessments of U.S. coastal waters and the Great Lakes. The report includes assessments of the nation’s estuaries in the contiguous 48 states and Puerto Rico.

Recent lake ice-out phenology within and among lake districts of Alaska, U.S.A.

USGS Publications Warehouse

Arp, Christopher D.; Jones, Benjamin M.; Grosse, Guido

2013-01-01

The timing of ice-out in high latitudes is a fundamental threshold for lake ecosystems and an indicator of climate change. In lake-rich regions, the loss of ice cover also plays a key role in landscape and climatic processes. Thus, there is a need to understand lake ice phenology at multiple scales. In this study, we observed ice-out timing on 55 large lakes in 11 lake districts across Alaska from 2007 to 2012 using satellite imagery. Sensor networks in two lake districts validated satellite observations and provided comparison with smaller lakes. Over this 6 yr period, the mean lake ice-out for all lakes was 27 May and ranged from 07 May in Kenai to 06 July in Arctic Coastal Plain lake districts with relatively low inter-annual variability. Approximately 80% of the variation in ice-out timing was explained by the date of 0°C air temperature isotherm and lake area. Shoreline irregularity, watershed area, and river connectivity explained additional variation in some districts. Coherence in ice-out timing within the lakes of each district was consistently strong over this 6 yr period, ranging from r-values of 0.5 to 0.9. Inter-district analysis of coherence also showed synchronous ice-out patterns with the exception of the two arctic coastal districts where ice-out occurs later (June–July) and climatology is sea-ice influenced. These patterns of lake ice phenology provide a spatially extensive baseline describing short-term temporal variability, which will help decipher longer term trends in ice phenology and aid in representing the role of lake ice in land and climate models in northern landscapes.

A 400-year phytolith-based reconstruction of wild rice (Zizania palustris) abundance from Mud Lake core sediments, Fond du Lac Band of Lake Superior Chippewa Reservation, Minnesota, USA.

NASA Astrophysics Data System (ADS)

Munoz, R.; Caylor, E.; Yost, C. L.; Drake, C.; Ladwig, J. L.; Myrbo, A.; Howes, T.

2014-12-01

Wild rice (Zizania palustris L.) is an aquatic grass with spiritual and subsistence significance to Native people of the Great Lakes region of North America. Mud Lake (Mashkiigwaagamaag), located on the Fond du Lac Band of Lake Superior Chippewa Reservation in Carlton County, Minnesota, USA, once supported an extensive population of wild rice (manoomin). However, early 20th century attempts to ditch and drain surrounding wetlands for landuse intensification severely altered the natural hydrological system that supports wild rice. Fond du Lac Resource Management (FDLRM) technicians are currently working to increase the wild rice population in Mud Lake. As part of these efforts, this phytolith study was undertaken to better understand how wild rice abundance has fluctuated over the past 400 years, with particular emphasis on the 19th and 20th centuries. Phytoliths are microscopic opal silica plant remains that are incorporated into soils and lake sediments after the plant-parts that contain them decay. Wild rice produces phytolith morphotypes that are unequivocally diagnostic. Mud Lake core MNMN-MUD11-1C-1P-1 (46°43'38.39"N, 92°42'2.45"W) was piston cored by LacCore (National Lacustrine Core Facility) and FDLRM technicians on 24 May 2011. Initial core descriptions, multi-sensor core logging, phytolith sampling and phytolith extractions were completed during the summer of 2014 at LacCore. Wild rice phytolith identification and quantification was conducted on twelve samples using brightfield microscopy at 400x magnification. Wild rice phytolith concentration values ranged from 68 to 2,300 phytoliths/cm3. Wild rice accumulation rates ranged from 9 to 383 phytoliths/ cm2/yr, peaking in 1952 AD. Wild rice abundance in Mud Lake appears to be influenced by a complex set of variables that include anthropogenic disturbance, climatic events and aquatic plant community succession.

Aircraft and satellite monitoring of water quality in Lake Superior near Duluth

NASA Technical Reports Server (NTRS)

Scherz, J. P.; Sydor, M.; Vandomelen, J. F.

1974-01-01

Satellite images and low altitude aerial photographs often show vivid discolorations in water bodies. Extensive laboratory analysis shows that water reflectance, which causes brightness on aerial images, positively correlates to the water quality parameter of turbidity, which on a particular day correlates to suspended solids. Work with low altitude photography on three overcast days and with ERTS images on five clear days provides positive correlation of image brightness to the high turbidity and solids which are present in Lake Superior near Duluth over 50% of the time. Proper use of aerial images would have shown that an $8,000,000 drinking water intake constructed in the midst of this unpotable, turbid water should have been located 6 miles north in clear, usable water. Noise effects such as skylight reflection, atmospheric effects, and depth penetration also must be understood for operational use of remote sensing for water quality monitoring and are considered in the paper.

Using multiple gears to assess acoustic detectability and biomass of fish species in lake superior

USGS Publications Warehouse

Yule, D.L.; Adams, J.V.; Stockwell, J.D.; Gorman, O.T.

2007-01-01

Recent predator demand and prey supply studies suggest that an annual daytime bottom trawl survey of Lake Superior underestimates prey fish biomass. A multiple-gear (acoustics, bottom trawl, and midwater trawl) nighttime survey has been recommended, but before abandoning a long-term daytime survey the effectiveness of night sampling of important prey species must be verified. We sampled three bottom depths (30, 60, and 120 m) at a Lake Superior site where the fish community included all commercially and ecologically important species. Day and night samples were collected within 48 h at all depths during eight different periods (one new and one full moon period during both early summer and late summer to early fall over 2 years). Biomass of demersal and benthic species was higher in night bottom trawl samples than in day bottom trawl samples. Night acoustic collections showed that pelagic fish typically occupied water cooler than 15°C and light levels less than 0.001 lx. Using biomass in night bottom trawls and acoustic biomass above the bottom trawl path, we calculated an index of acoustic detectability for each species. Ciscoes Coregonus artedi, kiyis C. kiyi, and rainbow smeltOsmerus mordax left the bottom at night, whereas bloaters C. hoyi stayed nearer the bottom. We compared the biomass of important prey species estimated with two survey types: day bottom trawls and night estimates of the entire water column (bottom trawl biomass plus acoustic biomass). The biomass of large ciscoes (>200 mm) was significantly greater when measured at night than when measured during daylight, but the differences for other sizes of important species did not vary significantly by survey type. Nighttime of late summer is a period when conditions for biomass estimation are largely invariant, and all important prey species can be sampled using a multiple-gear approach.

Magnetic investigation of the mid-Holocene aged coastal lake Heimerdalsvatnet in the Lofoten Islands, northern Norway

NASA Astrophysics Data System (ADS)

Murdock, K. J.; Brown, L. L.

2012-12-01

The coastal lake Heimerdalsvatnet is located on the island of Vestvågøya in the Lofoten Islands off the northern coast of Norway. Recently, Balascio et al. (2011) performed a comprehensive investigation of the lake using bathymetric and sub-bottom profiles, bulk geochemistry, diatom assemblages, molecular biomarkers, high resolution X-ray fluorescence (XRF) scans, and magnetic susceptibility to study its geologic history over the past 7800 years. They determined the lake had undergone a regressive sea level sequence and identified three distinct and separate units exemplifying the transition of a restricted marine environment within the lake to a completely freshwater lacustrine setting. Unit I, located at the bottom of the 5.8m sediment core, spans 7800-6500 years before present and is at a period of time when sea level was higher than the edge of the lake basin. Magnetic susceptibility is extremely low during this period, and it is theorized that this is due to stratification within the lake from a density difference between the marine salt water and the influx of freshwater. Unit II is broken into Unit IIa and IIb, making up the transitional period within the lake history from 6500 to 4900 years before present. This phase is marked by fluxes of higher and lower magnetic susceptibility and shifts between more freshwater to brackish water biological markers. Unit III (4900 years to present) has high magnetic susceptibility compared to the other two units, and represents the final stage of the lake as a completely freshwater environment. Questions remain about the lake, such as what was driving the changes in magnetic susceptibility? Was it dilution of the magnetic grains due to higher productivity of organisms within the lake, or is it related to dissolution of magnetite due to anoxic conditions caused by lake stratification? Rock magnetic investigations using magnetic susceptibility, hysteresis parameters, and Curie temperature analyses have led to a better

Ciscoes (Coregonus, subgenus Leucichthys) of the Laurentian Great Lakes and Lake Nipigon

USGS Publications Warehouse

Eshenroder, Randy L.; Vecsei, Paul; Gorman, Owen T.; Yule, Daniel; Pratt, Thomas C.; Mandrak, Nicholas E.; Bunnell, David B.; Muir, Andrew M.

2016-01-01

This study of the ciscoes (Coregonus, subgenus Leucichthys) of the Great Lakes and Lake Nipigon represents a furtherance through 2015 of field research initiated by Walter Koelz in 1917 and continued by Stanford Smith in the mid-1900s—a period spanning nearly a century. Like Koelz’s study, this work contains information on taxonomy, geographical distribution, ecology, and status of species (here considered forms). Of the seven currently recognized forms (C. artedi, C. hoyi, C. johannae, C. kiyi, C. nigripinnis, C. reighardi, and C. zenithicus) described by Koelz as major in his 1929 monograph, two (C. johannae and C. reighardi) are extinct. In addition, C. alpenae, described by Koelz but subsequently synonymized with C. zenithicus, although extinct, is recognized as valid making a total of eight major forms. Six of these forms, all but C. artedi and C. hoyi, have been lost from Lake Michigan, and seven have been lost from Lake Huron, leaving in Lake Huron only C. artedi and an introgressed deepwater form that we term a hybrid swarm. C. artedi appears, like its sister form C. alpenae, to have been lost from Lake Erie. Only C. artedi remains extant in Lake Ontario, its three sister forms (C. hoyi, C. kiyi, and C. reighardi) having disappeared long ago.Lakes Superior and Nipigon have retained their original species flocks consisting of four forms each: C. artedi, C. hoyi, and C. zenithicus in both lakes; C. kiyi in Lake Superior; and C. nigripinnis in Lake Nipigon. Morphological deviations from the morphotypes described by Koelz have been modest in contemporary samples. Overall, C. kiyi and C. artedi were the most morphologically stable forms while C. hoyi, C. nigripinnis, and C. zenithicus were the least stable. Although contemporary populations of C. artedi from Lakes Michigan and Huron are highly diverged from the morphotypes described by Koelz, the contemporary samples were of undescribed deep-bodied forms unlikely to have been sampled by Koelz because of

Energy density of bloaters in the upper Great Lakes

USGS Publications Warehouse

Pothoven, Steven A.; Bunnell, David B.; Madenjian, Charles P.; Gorman, Owen T.; Roseman, Edward F.

2012-01-01

We evaluated the energy density of bloaters Coregonus hoyi as a function of fish size across Lakes Michigan, Huron, and Superior in 2008–2009 and assessed how differences in energy density are related to factors such as biomass density of bloaters and availability of prey. Additional objectives were to compare energy density between sexes and to compare energy densities of bloaters in Lake Michigan between two time periods (1998–2001 and 2008–2009). For the cross-lake comparisons in 2008, energy density increased with fish total length (TL) only in Lake Michigan. Mean energy density adjusted for fish size was 8% higher in bloaters from Lake Superior than in bloaters from Lake Huron. Relative to fish in these two lakes, small (175 mm TL) bloaters had higher energy density. In 2009, energy density increased with bloater size, and mean energy density adjusted for fish size was about 9% higher in Lake Michigan than in Lake Huron (Lake Superior was not sampled during 2009). Energy density of bloaters in Lake Huron was generally the lowest among lakes, reflecting the relatively low densities of opossum shrimp Mysis diluviana and the relatively high biomass of bloaters reported for that lake. Other factors, such as energy content of prey, growing season, or ontogenetic differences in energy use strategies, may also influence cross-lake variation in energy density. Mean energy density adjusted for length was 7% higher for female bloaters than for male bloaters in Lakes Michigan and Huron. In Lake Superior, energy density did not differ between males and females. Finally, energy density of bloaters in Lake Michigan was similar between the periods 2008–2009 and 1998–2001, possibly due to a low population abundance of bloaters, which could offset food availability changes linked to the loss of prey such as the amphipods Diporeia spp.

Survival of lake trout eggs and fry reared in water from the upper Great Lakes

USGS Publications Warehouse

Mac, Michael J.; Edsall, Carol Cotant; Seelye, James G.

1985-01-01

As part of continuing studies of the reproductive failure of lake trout (Salvelinus namaycush) in Lake Michigan, we measured the survival of lake trout eggs and fry of different origins and reared in different environments. Eggs and milt were stripped from spawning lake trout collected in the fall of 1980 from southeastern Lake Michigan, northwestern Lake Huron, south central Lake Superior, and from hatchery brood stock. Eggs from all sources were incubated, and the newly hatched fry were reared for 139 days in lake water from each of the three upper Great Lakes and in well water. Survival of eggs to hatching at all sites was lowest for those from Lake Michigan (70% of fertilized eggs) and highest for eggs from Lake Superior (96%). Comparisons of incubation water from the different lakes indicated that hatching success of eggs from all sources was highest in Lake Huron water, and lowest in Lake Michigan water. The most notable finding was the nearly total mortality of fry from eggs of southeastern Lake Michigan lake trout. At all sites, the mean survival of Lake Michigan fry through 139 days after hatching was only 4% compared to near 50% for fry from the other three sources. In a comparison of the rearing sites, little influence of water quality on fry survival was found. Thus, the poor survival was associated with the source of eggs and sperm, not the water in which the fry were reared.

Mapping invasive Phragmites australis in the coastal Great Lakes with ALOS PALSAR satellite imagery for decision support

USGS Publications Warehouse

Bourgeau-Chavez, Laura L.; Kowalski, Kurt P.; Carlson Mazur, Martha L.; Scarbrough, Kirk A.; Powell, Richard B.; Brooks, Colin N.; Huberty, Brian; Jenkins, Liza K.; Banda, Elizabeth C.; Galbraith, David M.; Laubach, Zachary M.; Riordan, Kevin

2013-01-01

The invasive variety of Phragmites australis (common reed) forms dense stands that can cause negative impacts on coastal Great Lakes wetlands including habitat degradation and reduced biological diversity. Early treatment is key to controlling Phragmites, therefore a map of the current distribution is needed. ALOS PALSAR imagery was used to produce the first basin-wide distribution map showing the extent of large, dense invasive Phragmites-dominated habitats in wetlands and other coastal ecosystems along the U.S. shore of the Great Lakes. PALSAR is a satellite imaging radar sensor that is sensitive to differences in plant biomass and inundation patterns, allowing for the detection and delineation of these tall (up to 5 m), high density, high biomass invasive Phragmites stands. Classification was based on multi-season ALOS PALSAR L-band (23 cm wavelength) HH and HV polarization data. Seasonal (spring, summer, and fall) datasets were used to improve discrimination of Phragmites by taking advantage of phenological changes in vegetation and inundation patterns over the seasons. Extensive field collections of training and randomly selected validation data were conducted in 2010–2011 to aid in mapping and for accuracy assessments. Overall basin-wide map accuracy was 87%, with 86% producer's accuracy and 43% user's accuracy for invasive Phragmites. The invasive Phragmites maps are being used to identify major environmental drivers of this invader's distribution, to assess areas vulnerable to new invasion, and to provide information to regional stakeholders through a decision support tool.

Lake Superior water quality near Duluth from analysis of aerial photos and ERTS imagery

NASA Technical Reports Server (NTRS)

Scherz, J. P.; Van Domelen, J. F.

1973-01-01

ERTS imagery of Lake Superior in the late summer of 1972 shows dirty water near the city of Duluth. Water samples and simultaneous photographs were taken on three separate days following a heavy storm which caused muddy runoff water. The water samples were analyzed for turbidity, color, and solids. Reflectance and transmittance characteristics of the water samples were determined with a spectrophotometer apparatus. This same apparatus attached to a microdensitometer was used to analyze the photographs for the approximate colors or wavelengths of reflected energy that caused the exposure. Although other parameters do correlate for any one particular day, it is only the water quality parameter of turbidity that correlates with the aerial imagery on all days, as the character of the dirty water changes due to settling and mixing.

The reproduction of lake trout in southern Lake Superior

USGS Publications Warehouse

Eschmeyer, Paul H.

1955-01-01

Thirteen fish identified by commercial fishermen as siscowets (Salvelinus namaycush siscowet) also showed extensive individual variation in numbers of eggs, although egg production tended to increase with increasing length and weight of the fish. A mature female siscowet as small as 16.5 inches long and a 15.7-inch mature male were collected about 45 miles north of Grand Marais, Michigan. Combined data from all collections showed that spawning of lake trout or siscowets may occur during at least 6 months of the year (June to November).

EPA Research Strengthens Great Lakes Restoration Initiative

EPA Science Inventory

As the largest group of freshwater lakes on Earth, the Great Lakes (Lakes Erie, Huron, Michigan, Ontario and Superior) are a source of economic prosperity, recreation and raw materials. Human activity, however, has resulted in pollution and other stressors. The Great Lakes curren...

Introduction to the Proceedings of the 1994 International Conference on Restoration of Lake Trout in the Laurentian Great Lakes

USGS Publications Warehouse

Selgeby, James H.

1995-01-01

Lake trout (Salvelinus namaycush) restoration in the Great Lakes began in the 1950s when stocking of artificially propagated lake trout was coupled with the first attempts at sea lamprey (Petromyzon marinus) control. A major milestone in the restoration process was recorded when a selective sea lamprey larvicide was identified in 1958 (Applegate et al. 1958) and then applied broad scale in Lake Superior in 1958-60 (Applegate et al. 1961). Other milestones include the expansion of the sea lamprey control programs into Lakes Michigan and Huron in 1960 (sustained usage in Lake Huron began in 1966, Smith and Tibbles 1980), Lake Ontario in 1971-72 (Elrod et al. 1995), and Lake Erie in 1986 (Cornelius et al. 1995). Following the collapse of lake trout in the Great Lakes and the implementation of massive stocking of hatchery-reared fish and effective sea lamprey control, the first documented evidence of nearshore natural reproduction of lake trout was in Lake Superior in 1965 (Dryer and King 1968), in Lake Michigan in 1980 (Jude et al. 1981), in Lake Huron in 1981-82 (Nester and Poe 1984), and in Lake Ontario in 1986 (Marsden et al. 1988).

Persistence of Coastal Vegetation in Supratidal Zones of Northern China

PubMed Central

Yang, Hongxiao; Chu, Jianmin

2013-01-01

Coastal vegetation comprises a number of coastal specialists and terrestrial generalists. It remains unclear how they persist on disturbed and undisturbed coastal conditions. We tested the hypothesis that coastal specialists may be superior to terrestrial generalists on supratidal zones of coasts, but their superiority can be influenced by human disturbances. Eight separate sandy coasts of the Shandong Peninsula were sampled, representing for disturbed and undisturbed sandy coasts. Plants growing on their supratidal zones were surveyed. On this basis, we compared the relative dominances, niche widths, and commonness of all species, and also analyzed species diversities of the coasts. Coastal specialists were found to be more common and widespread on supratidal zones of the sandy coasts than terrestrial generalists haphazardly invading from hinterlands. Coastal specialists exhibited lower Sørensen dissimilarities than terrestrial generalists among the coasts. Tourist trampling seemed more detrimental than pond fishery to coastal vegetation. Relative to terrestrial generalists, coastal specialists responded to human disturbances more deterministically, with steady decreases in species diversities. These evidences verify that coastal specialists are intrinsically superior to terrestrial generalists on supratidal zones of coasts, especially of undisturbed coasts, because their dispersal among coasts adapts well to local storm surge regime. They also validate that human disturbances can depress the superiority of coastal specialists, partly by inducing invasion of terrestrial generalists. PMID:24224026

ALL THAT "PHRAG": BRINGING ENGINEERING, WETLAND ECOLOGY, ENVIRONMENTAL SCIENCE, AND LANDSCAPE ECOLOGY TO BEAR ON THE QUESTION OF COMMON REED IN GREAT LAKES COASTAL WETLANDS

EPA Science Inventory

Coastal wetlands are among the most fragmented and disturbed ecosystems and the Great Lakes are no exception. One possible result is the observed increase in the presence and dominance of invasive and other opportunistic plant species, such as the common reed (Phragmites australi...

Status of the amphipod Diporeia Spp. in Lake Superior, 2011

EPA Science Inventory

Amphipods of the genus Diporeia have historically been the dominant benthic macroinvertebrates in deeper waters of the Laurentian Great Lakes. Although Diporeia populations in the lower Great Lakes have experienced severe declines in recent years, densities have remained relativ...

Taking Teachers from the River to the Coast: a COSEE Great Lakes and Lake Superior NERR Collaboration

EPA Science Inventory

The Center for Ocean Sciences Education Excellence (COSEE) Great Lakes Shipboard and Shoreline Science Workshop provides 15 formal and informal educators of G5-10 an opportunity to spend a week aboard the US EPA’s 180’ R/V Lake Guardian working side-by-side with Great Lakes scien...

HISTORICAL SNOW AMOUNTS IN THE LAKE EFFECT REGION OF LAKE SUPERIOR: EVIDENCE OF CLIMATE CHANGE IN THE GREAT LAKES

EPA Science Inventory

Recent studies (Levitus et al., .2000) suggest a warming of the world ocean over the past 50 years. This could be occurring in the Great Lakes also but thermal measurements are lacking. Historical trends in natural phenomena, such as the duration of ice cover on lakes, provide in...

Tracing multi-habitat support of coastal fishes

EPA Science Inventory

Hydrologic linkages among coastal wetland and nearshore areas allow coastal fish to move among the habitats, which has led to a variety of habitat use patterns. In the Great Lakes, fine-scale microchemical analyses of yellow perch otoliths have revealed life-history categories th...

The new diatom training set from the Polish Baltic coast and diatom-based transfer functions as a tool for understanding past changes in the southern Baltic coastal lakes

NASA Astrophysics Data System (ADS)

Lutyńska, Monika; Szpikowska, Grażyna; Woszczyk, Michał; Suchińska, Anita; Burchardt, Lubomira; Messyasz, Beata

2014-05-01

The transfer function method has been developed as a useful tool for reconstruction of the past environmental changes. It is based on the assumption that the modern species, which ecological requirements are known, can be used to quantitative reconstructions of the past changes. The aim of the study was to gather test sets and to build diatom-based transfer function, which can be used to reconstruct changes in the trophic state and salinity in the coastal lakes on the Polish Baltic coast. In the previous years there were several attempts made to reconstruct these parameters in lagoonal waters on the Baltic coasts in Germany, Denmark, Finland, Netherland, Sweden and Norway. But so far there is no diatom test set and transfer function was built for the Polish coastal lakes. We sample diatoms form 12 lakes located along the polish Baltic coast. At the same time we monitor the physical-chemical conditions in the lakes, which includes lake water chemical composition (chlorides, phosphorous and sulphur), pH, salinity, conductivity, temperature, dissolved oxygen. We collect samples form the lakes as well as from the Baltic Sea and we analyse the whole phytoplankton composition, however the special focus in put on diatoms. The results of the analysis show seasonal changes in the chemical and physical water properties. The diatom assemblage composition and species frequency also changed significantly. This study is a contribution to the projects: NN 306 064 640 financed by National Science Centre, Poland and Virtual Institute ICLEA (Integrated Climate and Landscape Evolution Analysis) funded by the Helmholtz Association.

Using XRF Geochemical Data to Differentiate Storm Event Deposits in a Backbarrier Lake in Coastal Louisiana

NASA Astrophysics Data System (ADS)

Dietz, M.; Liu, K. B.; Bianchette, T. A.; Yao, Q.; McCloskey, T.

2016-12-01

Hurricanes Gustav and Ike consecutively impacted coastal Louisiana in 2008 and generated significant storm surges. Three sediment cores taken from Bay Champagne, a coastal backbarrier lake near Port Fourchon, Louisiana, clearly show a deposition layer of clastic sediment up to 17 cm thick attributable to these two storms. X-ray fluorescence (XRF) analysis indicates that the two storm events can be distinguished from one another based on contrasting geochemical profiles. The bottom layer, presumably deposited by Hurricane Gustav, has high concentrations of S, Cl, Ca, and Sr, suggesting a strong marine influence. The top layer, presumably attributed to Hurricane Ike, has high concentrations of Ti, Mn, Fe and Zn, indicative of material of terrestrial origin. The elemental concentration profiles suggest that the storm deposits in each core were deposited through two distinct hydrological processes: a storm surge -driven marine intrusion during Hurricane Gustav, followed by intensive freshwater flooding during Hurricane Ike. Using these deposits as modern analogs, this technique could be applied to characterize older storm layers in the sedimentary record and potentially provide information about their respective depositional mechanisms.

Embryotoxicity of Great Lakes lake trout extracts to developing rainbow trout

USGS Publications Warehouse

Wright, Peggy J.; Tillitt, Donald E.

1999-01-01

Planar halogenated hydrocarbons (PHHs), such as polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls are present in aquatic systems, and are known to produce adverse effects in fish. This study investigated the embryotoxicity of PHH mixtures through the nanoinjection of environmental extracts into newly fertilized eggs from two strains of rainbow trout. Organic extracts were obtained from whole adult lake trout collected from Lake Michigan in 1988 and Lake Superior in 1994. The graded doses of the final extracts used for injection were quantified as 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic-equivalents (TEQs) based on the concentrations of dioxins, furans and non-o-PCBs in each, and as equivalent amounts found in the eggs of the original lake trout (eggEQ). Total TEQs in the lake trout were 14.7 pg TEQ/g in the Lake Michigan sample and 7.3 pg TEQ/g in the Lake Superior sample. The extract of the Lake Michigan lake trout was embryotoxic to rainbow trout; LD50 values were 35 eggEQ (15–90, 95% F.L.) in the Arlee strain and 14 eggEQ (5–99, 95% F.L.) in the Erwin strain of rainbow trout. The LD50 values of the Lake Michigan extract in either of these strains of rainbow trout fall within the actual range of TCDD LD50values based on TEQs. This indicates that an additive model of toxicity is appropriate to quantify PHHs in relation to early life stage mortality in fish. Gross lesions characteristic of exposure to PHHs (i.e. yolk-sac edema, craniofacial deformities, and hemorrhaging) increased in a dose-related manner. The lowest observable adverse effect concentrations (LOAEC) for these gross lesions and cumulative mortalities suggests that current concentrations of PHHs in lake trout from Lake Michigan are above a threshold for adverse effects and these compounds may have implications on the lack of recruitment in certain Great Lakes lake trout populations.

Imaging the midcontinent rift beneath Lake Superior using large aperture seismic data

USGS Publications Warehouse

Tréhu, Anne M.; Morel-a-l'Huissier, Patrick; Meyer, R.; Hajnal, Z.; Karl, J.; Mereu, R.F.; Sexton, John L.; Shay, J.; Chan, W. K.; Epili, D.; Jefferson, T.; Shih, X. R.; Wendling, S.; Milkereit, B.; Green, A.; Hutchinson, Deborah R.

1991-01-01

We present a detailed velocity model across the 1.1 billion year old Midcontinent Rift System (MRS) in central Lake Superior. The model was derived primarily from onshore-offshore large-aperture seismic and gravity data. High velocities obtained within a highly reflective half-graben that was imaged on coincident seismic reflection data demonstrate the dominantly mafic composition of the graben fill and constrain its total thickness to be at least 30km. Strong wide-angle reflections are observed from the lower crust and Moho, indicating that the crust is thickest (55–60km) beneath the axis of the graben. The total crustal thickness decreases rapidly to about 40 km beneath the south shore of the lake and decreases more gradually to the north. Above the Moho is a high-velocity lower crust interpreted to result from syn-rift basaltic intrusion into and/or underplating beneath the Archean lower crust. The lower crust is thickest beneath the axis of the main rift half-graben. A second region of thick lower crust is found approximately 100km north of the axis of the rift beneath a smaller half graben that is interpreted to reflect an earlier stage of rifting. The crustal model presented here resembles recent models of some passive continental margins and is in marked contrast to many models of both active and extinct Phanerozoic continental rift zones. It demonstrates that the Moho is a dynamic feature, since the pre-rift Moho is probably within or above the high-velocity lower crust, whereas the post-rift Moho is defined as the base of this layer. In the absence of major tectonic activity, however, the Moho is very stable, since the large, abrupt variations in crustal thickness beneath the MRS have been preserved for at least a billion years.

Genetic identity of brook trout in Lake Superior south shore streams: Potential for genetic monitoring of stocking and rehabilitation efforts

USGS Publications Warehouse

Sloss, Brian L.; Jennings, Martin J.; Franckowiak, R.; Pratt, D.M.

2008-01-01

Rehabilitation of migratory ('coaster') brook trout Salvelinus fontinalis along Lake Superior's south shore is a topic of high interest among resource stakeholders and management agencies. Proposed strategies for rehabilitation of this brook trout life history variant in Wisconsin include supplemental stocking, watershed management, habitat rehabilitation, harvest regulations, or a combination thereof. In an effort to evaluate the success of coaster brook trout rehabilitation efforts, we collected genetic data from four populations of interest (Whittlesey Creek, Bois Brule River, Bark River, and Graveyard Creek) and the hatchery sources used in the Whittlesey Creek supplementation experiment. We characterized the genetic diversity of 30 individuals from each of four populations using 13 microsatellite DNA loci. Levels of genetic variation were consistent with those in similar studies conducted throughout the basin. Significant genetic variation among the populations was observed, enabling adequate population delineation through assignment tests. Overall, 208 of the 211 sampled fish (98.6%) were correctly assigned to their population of origin. Simulated F1 hybrids between two hatchery strains and the Whittlesey Creek population were identifiable in the majority of attempts (90.5-100% accuracy with 0-2.5% error). The genetic markers and analytical techniques described provide the ability to monitor the concurrent coaster brook trout rehabilitation efforts along Wisconsin's Lake Superior south shore, including the detection of hybridization between hatchery and native populations. ?? Copyright by the American Fisheries Society 2008.

Fish community changes in the St. Louis River estuary, Lake Superior, 1989-1996: Is it ruffe or population dynamics?

USGS Publications Warehouse

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

1998-01-01

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 an unintentional introduction of ruffe. During the study, ruffe density increased and the densities of several native species decreased. The reductions of native stocks to the natural population dynamics of the same species from Chequamegon Bay, Lake Superior (an area with very few ruffe) were developed, where there was a 24-year record of density. Using these data, short- and long-term variations in catch and correlations among species within years were compared, and species-specific distributions were developed of observed trends in abundance of native fishes in Chequamegon Bay indexed by the slopes of densities across years. From these distributions and our observed trend-line slopes from the St. Louis River, probabilities of measuring negative change at the magnitude observed in the St. Louis River were estimated. Compared with trends in Chequamegon Bay, there was a high probability of obtaining the negative slopes measured for most species, which suggests natural population dynamics could explain, the declines rather than interactions with ruffe. Variable recruitment, which was not related to ruffe density, and associated density-dependent changes in mortality likely were responsible for density declines of native species.

High and Increasing Shoreline Erosion Rates of Thermokarst Lakes Set in Ice-Rich Permafrost Terrain of the Arctic Coastal Plain of Alaska

NASA Astrophysics Data System (ADS)

Bondurant, A. C.; Arp, C. D.; Jones, B. M.; Shur, Y.; Daanen, R. P.

2017-12-01

Thermokarst lakes are a dominant landform shaping landscapes and impacting permafrost on the Arctic Coastal Plain (ACP) of northern Alaska, a region of continuous permafrost. Here lakes cover greater than 20% of the landscape and drained lake basins cover an additional 50 to 60% of the landscape. The formation, expansion, and drainage of thaw lakes has been described by some researchers as part of a natural cycle that has reworked the ACP landscape during the Holocene. Yet the factors and processes controlling contemporary thermokarst lake expansion remain poorly described. This study focuses on the factors controlling expansion rates of thermokarst lakes in three ACP regions that vary in landscape history, ground-ice content, and lake morphology (i.e. size and depth), as well as evaluating changes through time. Through the use of historical aerial imagery, satellite imagery, and field observations, this study identifies the controlling factors at multiple spatial and temporal scales to better understand the processes relating to thermokarst lake expansion. Studies of 35 lakes across the ACP shows regional differences in expansion rate related to permafrost ice content ranging from an average expansion rate of 0.62 m/yr where ice content is highest ( 86%) to 0.16 m/yr where ice content is lowest (45%-71%). A subset of these lakes analyzed over multiple time periods show increasing rates of erosion, with average rates being 37% higher over the period 1979-2002 (0.73 m/yr) compared to 1948-1979 (0.53 m/yr). These increased rates of erosion have important implications for the regional hydrologic cycle and localized permafrost degradation. Predicting how thermokarst lakes will behave locally and on a landscape scale is increasingly important for managing habitat and water resources and informing models of land-climate interactions in the Arctic.

A Four Lake Latitudinal Comparison Along Coastal Southern to Central California: A Late-Holocene Perspective on the Western US Precipitation Dipole.

NASA Astrophysics Data System (ADS)

Kirby, M.; Nichols, K. E.; Ramezan, R.; Palermo, J. A.; Hiner, C.; Bonuso, N.; Patterson, W. P.; Silveira, E.

2016-12-01

One of the dominant hydroclimatic features of the western United States is the winter season precipitation dipole. The dipole is characterized by a N-S antiphased precipitation regime presently centered on 40° N latitude (Cayan et al., 1998; Dettinger et al., 1998; Wise, 2010). For example, the position of the dipole dictates where CA receives its winter precipitation; thus, it is critical to understand the dipole from a paleoperspective, which at present is poorly known. Here, we present four lake sites spanning 33°-36° N latitude along coastal CA. These sites include: Lake Elsinore, Crystal Lake, Zaca Lake, and Abbott Lake. All four of these sites are located south of the dipole's average historic (since 1950 AD) latitude. The predominant hydroclimatic indicator is similar for each basin (i.e., grain size); although, several other indicators are used for independent verification/assessment of the grain size interpretation. Notably, these lakes contain varied age control, which limits site-to-site correlation without consideration of age model dependence. Following a Bayesian framework, MCMC algorithms in conjuction with radiocarbon dating will be used to estimate timestamps of sediment deposits with a degree of statistical uncertainty. Samples from the posterior distribution will be used to correlate hydroclimatic features between sites. Included in this analysis are tree ring records from the region to assess the similarities and differences as recorded in annually resolved tree ring drought reconstructions and decadally resolved lake sediment hydroclimatic records. Finally, the four sites are assessed in the context of tropical and north Pacific SST forcing.

NATIONAL COASTAL CONDITION REPORT IV | Science ...

EPA Pesticide Factsheets

The National Coastal Condition Report IV (NCCR IV) is the fourth in a series of environmental assessments of U.S. coastal waters and the Great Lakes. The report includes assessments of all the nation’s estuaries in the contiguous 48 states and Puerto Rico, south-eastern Alaska, Hawaii, the U.S. Virgin Islands, Guam, and American Samoa. The NCCR IV presents four main types of data: (1) coastal monitoring data, (2) coastal ocean/ offshore monitoring data, (3) offshore fisheries data, and (4) assessment and advisory data (new to NCCR IV). The NCCR IV relies heavily on coastal monitoring data from EPA’s National Coastal Assessment (NCA) to assess coastal condition by evaluating five indicators of condition—water quality, sediment quality, benthic community condition, coastal habitat loss, and fish tissue contaminants. To assess and report on the condition of the nation's coastal resources

A previously unrecognized path of early Holocene base flow and elevated discharge from Lake Minong to Lake Chippewa across eastern Upper Michigan

USGS Publications Warehouse

Loope, Walter L.; Jol, Harry M.; Fisher, Timothy G.; Blewett, William L.; Loope, Henry M.; Legg, Robert J.

2014-01-01

It has long been hypothesized that flux of fresh meltwater from glacial Lake Minong in North America's Superior Basin to the North Atlantic Ocean triggered rapid climatic shifts during the early Holocene. The spatial context of recent support for this idea demands a reevaluation of the exit point of meltwater from the Superior Basin. We used ground penetrating radar (GPR), foundation borings from six highway bridges, a GIS model of surface topography, geologic maps, U.S. Department of Agriculture–Natural Resources Conservation Service soils maps, and well logs to investigate the possible linkage of Lake Minong with Lake Chippewa in the Lake Michigan Basin across eastern Upper Michigan. GPR suggests that a connecting channel lies buried beneath the present interlake divide at Danaher. A single optical age hints that the channel aggraded to 225 m as elevated receipt of Lake Agassiz meltwater in the Superior Basin began to wane <10.6 ka. The large supply of sediment required to accommodate aggradation was immediately available at the channel's edge in the littoral shelves of abandoned Lake Algonquin and in distal parts of post-Algonquin fans. As discharge decreased further, the aggraded channel floor was quickly breached and interbasin flow to Lake Chippewa was restored. Basal radiocarbon ages on wood from small lakes along the discharge path and a GIS model of Minong's shoreline are consistent with another transgression of Minong after ca. 9.5 ka. At the peak of the latter transgression, the southeastern rim of the Superior Basin (Nadoway Drift Barrier) failed, ending Lake Minong. Upon Minong's final drop, aggradational sediments were deposited at Danaher, infilling the prior breach.

The Coastal Ocean Prediction Systems program: Understanding and managing our coastal ocean

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eden, H.F.; Mooers, C.N.K.

1990-06-01

The goal of COPS is to couple a program of regular observations to numerical models, through techniques of data assimilation, in order to provide a predictive capability for the US coastal ocean including the Great Lakes, estuaries, and the entire Exclusive Economic Zone (EEZ). The objectives of the program include: determining the predictability of the coastal ocean and the processes that govern the predictability; developing efficient prediction systems for the coastal ocean based on the assimilation of real-time observations into numerical models; and coupling the predictive systems for the physical behavior of the coastal ocean to predictive systems for biological,more » chemical, and geological processes to achieve an interdisciplinary capability. COPS will provide the basis for effective monitoring and prediction of coastal ocean conditions by optimizing the use of increased scientific understanding, improved observations, advanced computer models, and computer graphics to make the best possible estimates of sea level, currents, temperatures, salinities, and other properties of entire coastal regions.« less

An investigation of size-fractionated organic matter from Lake Superior and a tributary stream using radiocarbon, stable isotopes and NMR

NASA Astrophysics Data System (ADS)

Zigah, Prosper K.; Minor, Elizabeth C.; Abdulla, Hussain A. N.; Werne, Josef P.; Hatcher, Patrick G.

2014-02-01

This study investigated the concentration and isotopic composition of different size fractions of organic matter (OM) in Lake Superior and in one of its many tributary streams and rivers (Amity Creek, Duluth, Minnesota, USA). Structural compositional drivers of the Δ14C of high molecular weight (HMW, >1 kDa) dissolved organic carbon (DOC) in the lake were also evaluated. Low molecular weight (LMW, <1 kDa) DOC was the fraction containing the largest proportion (68-88%) of organic carbon (OC) in the lake. Particulate organic carbon (POC, >0.7 μm) was generally 13C-depleted (-29 ± 1.2‰) relative to “bulk” (<0.7 μm) DOC (-26.4 ± 0.7‰), “init” (<0.2 μm) DOC (-26.6 ± 0.8‰), HMW DOC (-26.9 ± 0.3‰) and LMW DOC (-26.5 ± 0.9‰), and had more variable 14C content (Δ14C of -94‰ to 53‰; 735 years BP to modern) than the other size fractions. Init DOC (Δ14C of 17-59‰), HMW DOC (Δ14C of 23-64‰) and LMW DOC (Δ14C of 16-62‰) all reflected contemporary (modern) radiocarbon signatures. Bulk DOC (Δ14C of -19‰ to 57‰; 90 years BP to modern) had modern radiocarbon values in the offshore sites (Δ14C of 2-57‰) with pre-aged samples (Δ14C of -8‰ to -19‰) seen at the nearshore site. HMW DOM was relatively N-poor (C:N of 12-19) compared to particulate organic matter (POM, C:N of 8-10) revealing either a more diagenetically altered state or contrasting sources. 13C NMR data showed that biochemical composition of HMW DOC in Lake Superior was dominated by carbohydrates (53-65%) with only trace aromatic components (2-4%). Structurally complex components such as heteropolysaccharides (HPS), amide/peptides and amino sugars (AMS) constitute 75-84% of HMW DOC whereas carboxylic-rich alicyclic molecules (CRAM) made up 16-25% of HMW DOC in the lake. Combined HPS and AMS, O-alkyl carbohydrate carbon, and total carbohydrate carbon contents were significantly positively correlated to the Δ14C of HMW DOC suggesting they contribute a contemporary 14C

A spatial classification and database for management, research, and policy making: The Great Lakes aquatic habitat framework

USGS Publications Warehouse

Wang, Lizhu; Riseng, Catherine M.; Mason, Lacey; Werhrly, Kevin; Rutherford, Edward; McKenna, James E.; Castiglione, Chris; Johnson, Lucinda B.; Infante, Dana M.; Sowa, Scott P.; Robertson, Mike; Schaeffer, Jeff; Khoury, Mary; Gaiot, John; Hollenhurst, Tom; Brooks, Colin N.; Coscarelli, Mark

2015-01-01

Managing the world's largest and most complex freshwater ecosystem, the Laurentian Great Lakes, requires a spatially hierarchical basin-wide database of ecological and socioeconomic information that is comparable across the region. To meet such a need, we developed a spatial classification framework and database — Great Lakes Aquatic Habitat Framework (GLAHF). GLAHF consists of catchments, coastal terrestrial, coastal margin, nearshore, and offshore zones that encompass the entire Great Lakes Basin. The catchments captured in the database as river pour points or coastline segments are attributed with data known to influence physicochemical and biological characteristics of the lakes from the catchments. The coastal terrestrial zone consists of 30-m grid cells attributed with data from the terrestrial region that has direct connection with the lakes. The coastal margin and nearshore zones consist of 30-m grid cells attributed with data describing the coastline conditions, coastal human disturbances, and moderately to highly variable physicochemical and biological characteristics. The offshore zone consists of 1.8-km grid cells attributed with data that are spatially less variable compared with the other aquatic zones. These spatial classification zones and their associated data are nested within lake sub-basins and political boundaries and allow the synthesis of information from grid cells to classification zones, within and among political boundaries, lake sub-basins, Great Lakes, or within the entire Great Lakes Basin. This spatially structured database could help the development of basin-wide management plans, prioritize locations for funding and specific management actions, track protection and restoration progress, and conduct research for science-based decision making.

National Coastal Condition Assessment

EPA Pesticide Factsheets

The NCCA is a collaborative, statistical survey of the nation's coastal waters and the Great Lakes. It is one of four national surveys that EPA and its partners conduct to assess the condition and health of the nation's water resources.

National Coastal Geology Program: a plan of geologic research on coastal erosion, coastal wetlands, polluted sediments, and coastal hard-mineral resources

USGS Publications Warehouse

,

1990-01-01

More than 50 percent of the U.S. population currently live within 50 miles of an ocean, Great Lake, or major estuary. According to forecasts, the concentration of people along our coastlines will continue to increase into the 21st century. In addition to residential and commercial buildings and facilities worth tens of billions of dollars, the coasts and associated wetlands are natural resources of tremendous value, with estimates in excess of $13 billion per year for commercial and recreational fisheries alone. Human activities and natural processes are stressing the coastal environment. * Each of the coastal states and island territories is suffering problems related to coastal erosion. * Deterioration of wetlands is widespread and of great public concern. * Pollutants carried by rivers or runoff are discharged directly into coastal waters and accumulate in the sediments on the sea floor, in some areas causing damage to living resources and presenting a threat to public health. * Onshore sources for hard-mineral resources, such as sand and gravel used for construction purposes, are becoming increasingly difficult to find. New sources are being sought in coastal waters. Coastal issues will become even more important into the next century if sea level is significantly influenced by climate change and other factors.

Status of the Amphipod Diporeia spp. in Lake Superior, poster presentation

EPA Science Inventory

The amphipod Diporeia has historically been the dominant benthic macroinvertebrate in deeper waters of the Laurentian Great Lakes. Although Diporeia populations in the lower Great Lakes have experienced severe declines in recent years, densities have remained relatively stable i...

CONNECTING WATERSHED CHARACTERISTICS TO NUTRIENT REGIME FROM HEADWATERS TO RECEIVING WATERS IN THE LAURENTIAL GREAT LAKES

EPA Science Inventory

We are evaluating the influence of position along the tributary-coastal wetland-lake continuum on the expression of watershed characteristics in the water quality of Great Lakes (GL) coastal ecosystems as part of an EPA study focused on determining stressor-response relationships...

Total and methyl-mercury seasonal particulate fluxes in the water column of a large lake (Lake Geneva, Switzerland).

PubMed

Díez, Elena Gascón; Graham, Neil D; Loizeau, Jean-Luc

2018-05-16

Concentrations and fluxes of total and methylmercury were determined in surface sediments and associated with settling particles at two sites in Lake Geneva to evaluate the sources and dynamics of this toxic contaminant. Total mercury concentrations measured in settling particles were different throughout the seasons and were greatly influenced by the Rhone River particulate inputs. Total mercury concentrations closer to shore (NG2) ranged between 0.073 ± 0.001 and 0.27 ± 0.01 μg/g, and between 0.038 ± 0.001 and 0.214 ± 0.008 μg/g at a site deeper in the lake (NG3). Total mercury fluxes ranged between 0.144 ± 0.002 and 3.0 ± 0.1 μg/m 2 /day at NG2, and between 0.102 ± 0.008 and 1.32 ± 0.08 μg/m 2 /day at NG3. Combined results of concentrations and fluxes showed that total mercury concentrations in settling particles are related to the season and particle inputs from the Rhone River. Despite an observed decrease in total mercury fluxes from the coastal zone towards the open lake, NG3 (~ 3 km from the shoreline) was still affected by the coastal boundary, as compared to distal sites at the center of the lake. Thus, sediment focusing is not efficient enough to redistribute contaminant inputs originating from the coastal zones, to the lake center. Methylmercury concentrations in settling particles largely exceeded the concentrations found in sediments, and their fluxes did not show significant differences with relation to the distance from shore. The methylmercury found associated with settling particles would be related to the lake's internal production rather than the effect of transport from sediment resuspension.

Habitat use by fishes of Lake Superior. I. Diel patterns of habitat use in nearshore and offshore waters of the Apostle Islands region

USGS Publications Warehouse

Gorman, O.T.; Yule, D.L.; Stockwell, J.D.

2012-01-01

Diel patterns of distribution of fishes in nearshore (15–80 m depth) and offshore (>80 m) waters of the Apostle Islands region of Lake Superior were described using bottom trawls, mid-water trawls, and acoustic gear during day and night sampling. These data revealed three types of diel migration: diel vertical migration (DVM), diel bank migration (DBM), and no migration. DVM was expressed by fishes migrating from benthopelagic to pelagic strata and DBM was expressed by fishes migrating horizontally from deeper waters in the day to shallower waters at night while remaining within the benthopelagic stratum. Most fishes that did not exhibit diel migration showed increased nighttime densities as a result of increased activity and movement from benthic to benthopelagic strata. Rainbow Smelt (Osmerus mordax), Cisco (Coregonus artedi), Bloater (C. hoyi), Kiyi (C. kiyi), juvenile Trout-Perch (Percopsis omiscomaycus), and adult siscowet (Salvelinus namaycush siscowet) exhibited DVM. Lake Whitefish (C. clupeaformis), lean Lake Trout (Salvelinus namaycush namaycush), and juvenile siscowet exhibited DBM. Adult Trout-Perch and adult Pygmy Whitefish (Prosopium coulteri) exhibited a mixture of DBM and DVM. Burbot (Lota lota), Slimy Sculpin (Cottus cognatus), Spoonhead Sculpin (C. ricei), and Deepwater Sculpin (Myoxocephalus thompsonii) did not exhibit diel migration, but showed evidence of increased nocturnal activity. Ninespine Stickleback (Pungitius pungitius) exhibited a mixture of DVM and non-migration. Juvenile Pygmy Whitefish did not show a diel change in density or depth distribution. Species showing ontogenetic shifts in depth distribution with larger, adult life stages occupying deeper waters included, Rainbow Smelt, lean and siscowet Lake Trout, Lake Whitefish, Pygmy Whitefish, Ninespine Stickleback and Trout-Perch. Of these species, siscowet also showed an ontogenetic shift from primarily DBM as juveniles to primarily DVM as adults. Across all depths, fishes

Sea lamprey mark type, marking rate, and parasite-host relationships for lake trout and other species in Lake Ontario

USGS Publications Warehouse

Lantry, Brian F.; Adams, Jean V.; Christie, Gavin; Schaner, Teodore; Bowlby, James; Keir, Michael; Lantry, Jana; Sullivan, Paul; Bishop, Daniel; Treska, Ted; Morrison, Bruce

2015-01-01

We examined how attack frequency by sea lampreys on fishes in Lake Ontario varied in response to sea lamprey abundance and preferred host abundance (lake trout > 433 mm). For this analysis we used two gill net assessment surveys, one angler creel survey, three salmonid spawning run datasets, one adult sea lamprey assessment, and a bottom trawl assessment of dead lake trout. The frequency of fresh sea lamprey marks observed on lake trout from assessment surveys was strongly related to the frequency of sea lamprey attacks observed on salmon and trout from the creel survey and spawning migrations. Attack frequencies on all salmonids examined were related to the ratio between the abundances of adult sea lampreys and lake trout. Reanalysis of the susceptibility to sea lamprey attack for lake trout strains stocked into Lake Ontario reaffirmed that Lake Superior strain lake trout were among the most and Seneca Lake strain among the least susceptible and that Lewis Lake strain lake trout were even more susceptible than the Superior strain. Seasonal attack frequencies indicated that as the number of observed sea lamprey attacks decreased during June–September, the ratio of healing to fresh marks also decreased. Simulation of the ratios of healing to fresh marks indicated that increased lethality of attacks by growing sea lampreys contributed to the decline in the ratios and supported laboratory studies about wound healing duration.

STATUS OF THE AMPHIPOD DIPOREIA SPP. IN LAKE SUPERIOR, 1994-2000

EPA Science Inventory

The amphipod Diporeia spp. is the dominant component of the Great Lakes benthic macroinvertebrate fauna in terms of both numbers and biomass, and plays an important role in the ecosystem. The Great Lakes Water Quality Agreement calls for the use of Diporeia as an indicator of ec...

Demographic and Component Allee Effects in Southern Lake Superior Gray Wolves

PubMed Central

Stenglein, Jennifer L.; Van Deelen, Timothy R.

2016-01-01

Recovering populations of carnivores suffering Allee effects risk extinction because positive population growth requires a minimum number of cooperating individuals. Conservationists seldom consider these issues in planning for carnivore recovery because of data limitations, but ignoring Allee effects could lead to overly optimistic predictions for growth and underestimates of extinction risk. We used Bayesian splines to document a demographic Allee effect in the time series of gray wolf (Canis lupus) population counts (1980–2011) in the southern Lake Superior region (SLS, Wisconsin and the upper peninsula of Michigan, USA) in each of four measures of population growth. We estimated that the population crossed the Allee threshold at roughly 20 wolves in four to five packs. Maximum per-capita population growth occurred in the mid-1990s when there were approximately 135 wolves in the SLS population. To infer mechanisms behind the demographic Allee effect, we evaluated a potential component Allee effect using an individual-based spatially explicit model for gray wolves in the SLS region. Our simulations varied the perception neighborhoods for mate-finding and the mean dispersal distances of wolves. Simulation of wolves with long-distance dispersals and reduced perception neighborhoods were most likely to go extinct or experience Allee effects. These phenomena likely restricted population growth in early years of SLS wolf population recovery. PMID:26930665

Demographic and Component Allee Effects in Southern Lake Superior Gray Wolves.

PubMed

Stenglein, Jennifer L; Van Deelen, Timothy R

2016-01-01

Recovering populations of carnivores suffering Allee effects risk extinction because positive population growth requires a minimum number of cooperating individuals. Conservationists seldom consider these issues in planning for carnivore recovery because of data limitations, but ignoring Allee effects could lead to overly optimistic predictions for growth and underestimates of extinction risk. We used Bayesian splines to document a demographic Allee effect in the time series of gray wolf (Canis lupus) population counts (1980-2011) in the southern Lake Superior region (SLS, Wisconsin and the upper peninsula of Michigan, USA) in each of four measures of population growth. We estimated that the population crossed the Allee threshold at roughly 20 wolves in four to five packs. Maximum per-capita population growth occurred in the mid-1990s when there were approximately 135 wolves in the SLS population. To infer mechanisms behind the demographic Allee effect, we evaluated a potential component Allee effect using an individual-based spatially explicit model for gray wolves in the SLS region. Our simulations varied the perception neighborhoods for mate-finding and the mean dispersal distances of wolves. Simulation of wolves with long-distance dispersals and reduced perception neighborhoods were most likely to go extinct or experience Allee effects. These phenomena likely restricted population growth in early years of SLS wolf population recovery.

Contaminant trends in lake trout and walleye from the Laurentian Great Lakes

USGS Publications Warehouse

DeVault, David S.; Hesselberg, Robert J.; Rodgers, Paul W.; Feist, Timothy J.

1996-01-01

Trends in PCBs, DDT, and other contaminants have been monitored in Great Lakes lake trout and walleye since the 1970s using composite samples of whole fish. Dramatic declines have been observed in concentrations of PCB, ΣDDT, dieldrin, and oxychlordane, with declines initially following first order loss kinetics. Mean PCB concentrations in Lake Michigan lake trout increased from 13 μg/g in 1972 to 23 μg/g in 1974, then declined to 2.6 μg/g by 1986. Between 1986 and 1992 there was little change in concentration, with 3.5 μg/g observed in 1992. ΣDDT in Lake Michigan trout followed a similar trend, decreasing from 19.2 μg/g in 1970 to 1.1 μg/g in 1986, and 1.2 μg/g in 1992. Similar trends were observed for PCBs and ΣDDT in lake trout from Lakes Superior, Huron and Ontario. Concentrations of both PCB and ΣDDT in Lake Erie walleye declined between 1977 and 1982, after which concentrations were relatively constant through 1990. When originally implemented it was assumed that trends in the mean contaminant concentrations in open-lake fish would serve as cost effective surrogates to trends in the water column. While water column data are still extremely limited it appears that for PCBs in lakes Michigan and Superior, trends in lake trout do reasonably mimic those in the water column over the long term. Hypotheses to explain the trends in contaminant concentrations are briefly reviewed. The original first order loss kinetics used to describe the initial decline do not explain the more recent leveling off of contaminant concentrations. Recent theories have examined the possibilities of multiple contaminant pools. We suggest another hypothesis, that changes in the food web may have resulted in increased bioaccumulation. However, a preliminary exploration of this hypothesis using a change point analysis was inconclusive.

Coastal processes influencing water quality at Great Lakes beaches

USGS Publications Warehouse

,

2013-01-01

In a series of studies along the Great Lakes, U.S. Geological Survey scientists are examining the physical processes that influence concentrations of fecal indicator bacteria and related pathogens at recreational beaches. These studies aim to estimate human health risk, improve management strategies, and understand the fate and transport of microbes in the nearshore area. It was determined that embayed beaches act as traps, accumulating Escherichia coli (E. coli) and other bacteria in the basin and even in beach sand. Further, shear stress and wave run-up could resuspend accumulated bacteria, leading to water-contamination events. These findings are being used to target beach design and circulation projects. In previous research, it was determined that E. coli followed a diurnal pattern, with concentrations decreasing throughout the day, largely owing to solar inactivation, but rebounding overnight. Studies at a Chicago beach identified the impact of wave-induced mass transport on this phenomenon, a finding that will extend our understanding of bacterial fate in the natural environment. In another series of studies, scientists examined the impact of river outfalls on bacteria concentrations, using mechanistic and empirical modeling. Through these studies, the models can indicate range and extent of impact, given E. coli concentration in the source water. These findings have been extended to extended lengths of coastlines and have been applied in beach management using empirical predictive modeling. Together, these studies are helping scientists identify and eliminate threats to human and coastal health.

Watershed and discharge influences on the phase distribution and tributary loading of total mercury and methylmercury into Lake Superior.

PubMed

Babiarz, Christopher; Hoffmann, Stephen; Wieben, Ann; Hurley, James; Andren, Anders; Shafer, Martin; Armstrong, David

2012-02-01

Knowledge of the partitioning and sources of mercury are important to understanding the human impact on mercury levels in Lake Superior wildlife. Fluvial fluxes of total mercury (Hg(T)) and methylmercury (MeHg) were compared to discharge and partitioning trends in 20 sub-basins having contrasting land uses and geological substrates. The annual tributary yield was correlated with watershed characteristics and scaled up to estimate the basin-wide loading. Tributaries with clay sediments and agricultural land use had the largest daily yields with maxima observed near the peak in water discharge. Roughly 42% of Hg(T) and 57% of MeHg was delivered in the colloidal phase. Tributary inputs, which are confined to near-shore zones of the lake, may be more important to the food-web than atmospheric sources. The annual basin-wide loading from tributaries was estimated to be 277 kg yr(-1) Hg(T) and 3.4 kg yr(-1) MeHg (5.5 and 0.07 mg km(-2) d(-1), respectively). Copyright © 2011 Elsevier Ltd. All rights reserved.

Midcontinent rift volcanism in the Lake Superior region: Sr, Nd, and Pb isotopic evidence for a mantle plume origin

USGS Publications Warehouse

Nicholson, S.W.; Shirey, S.B.

1990-01-01

Between 1091 and 1098 Ma, most of a 15- to 20-km thickness of dominantly tholeiitic basalt erupted in the Midcontinent Rift System of the Lake Superior region, North America. The Portage Lake Volcanics in Michigan, which are the younget MRS flood basalts, fall into distinctly high- and low-TiO2 types having different liquid lines of descent. Incompatible trace elements in both types of tholeiites are enriched compared to depleted or primitive mantle and both basalt types are isotopically indistinguishable. The isotopic enrichment of the MRS source compared to depleted mantle is striking and must have occurred at least 700 m.y. before 1100 Ma. There are two likely sources for such magmatism: subcontinental lithospheric mantle enriched during the early Proterozoic or enriched mantle derived from an upwelling plume. Decompression melting of an upwelling enriched mantle plume in a region of lithosphere thinned by extension could have successfully generated the enormous volume (850 ?? 103 km3) of relatively homogeneous magma in a restricted time interval. -from Authors

Three air quality studies: Great Lakes ozone formation and nitrogen dry deposition; and Tucson aerosol chemical characterization

NASA Astrophysics Data System (ADS)

Foley, Theresa

(arsenic, beryllium, cadmium, chromium, cobalt, lead, manganese, and nickel) in the southern Tucson metropolitan area. A Tucson company that uses beryllium oxide to manufacture thermally conductive ceramics has prompted strong citizen concern. This study found that the study area has good air quality with respect to PM10 and metals, with ambient concentrations meeting US Environmental Protection Agency and World Health Organization standards. Beryllium was detected only once (during a dust storm) and was ascribed to naturally-occurring beryllium in the suspended soil. The third paper (to be submitted to the Journal of Great Lakes Research) studies nitrogen dry deposition over Lake Michigan and Lake Superior. Numerous studies have shown that wet and dry deposition of nitrogen has contributed to the eutrophication of coastal waters and declining productivity of marine fisheries. Nitrogen dry deposition over the Great Lakes themselves, as opposed to the shorelines, has not been documented in the peer-reviewed literature. This paper calculates nitrogen dry deposition over Lake Michigan and Lake Superior, using aircraft measurements from the LADCO Aircraft Study, and finds that over-water, nitrogen dry deposition is a significant source of nitrogen to Lake Michigan and Lake Superior.

Changes in depth occupied by Great Lakes lake whitefish populations and the influence of survey design

USGS Publications Warehouse

Rennie, Michael D.; Weidel, Brian C.; Claramunt, Randall M.; Dunlob, Erin S.

2015-01-01

Understanding fish habitat use is important in determining conditions that ultimately affect fish energetics, growth and reproduction. Great Lakes lake whitefish (Coregonus clupeaformis) have demonstrated dramatic changes in growth and life history traits since the appearance of dreissenid mussels in the Great Lakes, but the role of habitat occupancy in driving these changes is poorly understood. To better understand temporal changes in lake whitefish depth of capture (Dw), we compiled a database of fishery-independent surveys representing multiple populations across all five Laurentian Great Lakes. By demonstrating the importance of survey design in estimating Dw, we describe a novel method for detecting survey-based bias in Dw and removing potentially biased data. Using unbiased Dw estimates, we show clear differences in the pattern and timing of changes in lake whitefish Dw between our reference sites (Lake Superior) and those that have experienced significant benthic food web changes (lakes Michigan, Huron, Erie and Ontario). Lake whitefish Dw in Lake Superior tended to gradually shift to shallower waters, but changed rapidly in other locations coincident with dreissenid establishment and declines in Diporeia densities. Almost all lake whitefish populations that were exposed to dreissenids demonstrated deeper Dw following benthic food web change, though a subset of these populations subsequently shifted to more shallow depths. In some cases in lakes Huron and Ontario, shifts towards more shallow Dw are occurring well after documented Diporeia collapse, suggesting the role of other drivers such as habitat availability or reliance on alternative prey sources.

A long record of extreme wave events in coastal Lake Hamana, Japan

NASA Astrophysics Data System (ADS)

Boes, Evelien; Yokoyama, Yusuke; Schmidt, Sabine; Riedesel, Svenja; Fujiwara, Osamu; Nakamura, Atsunori; Garrett, Ed; Heyvaert, Vanessa; Brückner, Helmut; De Batist, Marc

2017-04-01

Coastal Lake Hamana is located near the convergent tectonic boundary of the Nankai-Suruga Trough, along which the Philippine Sea slab is subducted underneath the Eurasian Plate, giving rise to repeated tsunamigenic megathrust earthquakes (Mw ≥ 8). A good understanding of the earthquake- and tsunami-triggering mechanisms is crucial in order to better estimate the complexity of seismic risks. Thanks to its accommodation space, Lake Hamana may represent a good archive for past events, such as tsunamis and tropical storms (typhoons), also referred to as "extreme wave" events. Characteristic event layers, consisting of sediment entrained by these extreme waves and their backwash, are witnesses of past marine incursions. By applying a broad range of surveying methods (reflection-seismic profiling, gravity coring, piston coring), sedimentological analyses (CT-scanning, XRF-scanning, multi-sensor core logging, grain size, microfossils etc.) and dating techniques (210Pb/137Cs, 14C, OSL, tephrochronology), we attempt to trace extreme wave event deposits in a multiproxy approach. Seismic imagery shows a vertical stacking of stronger reflectors, interpreted to be coarser-grained sheets deposited by highly energetic waves. Systematic sampling of lake bottom sediments along a transect from ocean-proximal to ocean-distal sites enables us to evaluate vertical and lateral changes in stratigraphy. Ocean-proximal, we observe a sequence of eight sandy units separated by silty background sediments, up to a depth of 8 m into the lake bottom. These sand layers quickly thin out and become finer-grained land-inward. Seismic-to-core correlations show a good fit between the occurrence of strong reflectors and sandy deposits, hence confirming presumptions based on acoustic imagery alone. Sand-rich intervals typically display a higher magnetic susceptibility, density and stronger X-ray attenuation. However, based on textural and structural differences, we can make the distinction between

Sediment deposition and sources into a Mississippi River floodplain lake; Catahoula Lake, Louisiana

USGS Publications Warehouse

Latuso, Karen D.; Keim, Richard F.; King, Sammy L.; Weindorf, David C.; DeLaune, Ronald D.

2017-01-01

Floodplain lakes are important wetlands on many lowland floodplains of the world but depressional floodplain lakes are rare in the Mississippi River Alluvial Valley. One of the largest is Catahoula Lake, which has existed with seasonally fluctuating water levels for several thousand years but is now in an increasingly hydrologically altered floodplain. Woody vegetation has been encroaching into the lake bed and the rate of this expansion has increased since major human hydrologic modifications, such as channelization, levee construction, and dredging for improvement of navigation, but it remains unknown what role those modifications may have played in altering lake sedimentation processes. Profiles of thirteen 137Cs sediment cores indicate sedimentation has been about 0.26 cm y− 1 over the past 60 years and has been near this rate since land use changes began about 200 years ago (210Pb, and 14C in Tedford, 2009). Carbon sequestration was low (10.4 g m− 2 y− 1), likely because annual drying promotes mineralization and export. Elemental composition (high Zr and Ti and low Ca and K) and low pH of recent (<~60 y) or surface sediments suggest Gulf Coastal Plain origin, but below the recent sediment deposits, 51% of sediment profiles showed influence of Mississippi River alluvium, rich in base cations such as K+, Ca2 +, and Mg2 +. The recent shift to dominance of Coastal Plain sediments on the lake-bed surface suggests hydrologic modification has disconnected the lake from sediment-bearing flows from the Mississippi River. Compared to its condition prior to hydrologic alterations that intensified in the 1930s, Catahoula Lake is about 15 cm shallower and surficial sediments are more acidic. Although these results are not sufficient to attribute ecological changes directly to sedimentological changes, it is likely the altered sedimentary and hydrologic environment is contributing to the increased dominance of woody vegetation.

Depth gradients in food-web processes linking habitats in large lakes: Lake Superior as an exemplar ecosystem

USGS Publications Warehouse

Sierszen, Michael E.; Hrabik, Thomas R.; Stockwell, Jason D.; Cotter, Anne M; Hoffman, Joel C.; Yule, Daniel L.

2014-01-01

Support of whole-lake food webs through trophic linkages among pelagic, profundal and littoral habitats appears to be integral to the functioning of large lakes. These linkages can be disrupted though ecosystem disturbance such as eutrophication or the effects of invasive species and should be considered in native species restoration efforts.

Tsunami history of an Oregon coastal lake reveals a 4600 yr record of great earthquakes on the Cascadia subduction zone

USGS Publications Warehouse

Kelsey, H.M.; Nelson, A.R.; Hemphill-Haley, E.; Witter, R.C.

2005-01-01

Bradley Lake, on the southern Oregon coastal plain, records local tsunamis and seismic shaking on the Cascadia subduction zone over the last 7000 yr. Thirteen marine incursions delivered landward-thinning sheets of sand to the lake from nearshore, beach, and dune environments to the west. Following each incursion, a slug of marine water near the bottom of the freshwater lake instigated a few-year-to-several-decade period of a brackish (??? 4??? salinity) lake. Four additional disturbances without marine incursions destabilized sideslopes and bottom sediment, producing a suspension deposit that blanketed the lake bottom. Considering the magnitude and duration of the disturbances necessary to produce Bradley Lake's marine incursions, a local tsunami generated by a great earthquake on the Cascadia subduction zone is the only accountable mechanism. Extreme ocean levels must have been at least 5-8 m above sea level, and the cumulative duration of each marine incursion must have been at least 10 min. Disturbances without marine incursions require seismic shaking as well. Over the 4600 yr period when Bradley Lake was an optimum tsunami recorder, tsunamis from Cascadia plate-boundary earthquakes came in clusters. Between 4600 and 2800 cal yr B.P., tsunamis occurred at the average frequency of ??? 3-4 every 1000 yr. Then, starting ???2800 cal yr B.P., there was a 930-1260 yr interval with no tsunamis. That gap was followed by a ???1000 yr period with 4 tsunamis. In the last millennium, a 670-750 yr gap preceded the A.D. 1700 earthquake and tsunami. The A.D. 1700 earthquake may be the first of a new cluster of plate-boundary earthquakes and accompanying tsunamis. Local tsunamis entered Bradley Lake an average of every 390 yr, whereas the portion of the Cascadia plate boundary that underlies Bradley Lake ruptured in a great earthquake less frequently, about once every 500 yr. Therefore, the entire length of the subduction zone does not rupture in every earthquake, and Bradley

Genetic variability among lake whitefish from Isle Royale and the Upper Great Lakes

USGS Publications Warehouse

Stott, Wendylee; Todd, Thomas N.; Kallemeyn, Larry

2004-01-01

The coregonine fishes from Isle Royale National Park represent a unique group that has escaped the successional changes observed elsewhere in North America. Analysis of microsatellite DNA loci revealed significant genetic differences among samples of lake whitefish (Coregonus clupeaformis) from Isle Royale, Lake Superior, and Lake Huron. The amount of genetic variation observed is consistent with that seen in other studies of whitefishes from North America. The lake whitefish from Isle Royale had previously been assigned sub-species status, but no evidence was found to support this. The effects of common ancestry and demographics both play a role in determining the relatedness of the populations. As with other fish species from Isle Royale and the upper Great Lakes, the lake whitefish have their origins in the Mississippi refugium.

Occurrence of alkylphenolic substances in a Great Lakes coastal marsh, Cootes Paradise, ON, Canada.

PubMed

Mayer, T; Bennie, D; Rosa, F; Rekas, G; Palabrica, V; Schachtschneider, J

2007-06-01

Occurrence and fate of alkylphenols (APs), known endocrine disruptors, were investigated in a Great Lakes coastal wetland, Cootes Paradise, ON. The wetland, which receives discharges from a Wastewater Treatment Plant (WTP) and several Combined Sewer Overflows (CSOs), is an important spawning ground for fish and crucial habitat for other fauna. Elevated concentrations of nonylphenol ethoxylates (NPEs) and their degradation product nonylphenol (NP) were found in water and sediment samples near the sources. Since transfer of APs through the food chain is of concern, we compared their concentrations in invertebrates from clean and contaminated sites. The results reveal transfer of alkylphenolics from sediments to biota and their accumulation in the invertebrate tissue, particularly the highly hydrophobic 4-NP, whose concentrations ranged from 1.9 to 6.3 microg g(-1). To our knowledge, this is the first study to evaluate AP concentrations in tissue of benthic invertebrates under real environmental conditions.

Lateral and subsurface flows impact arctic coastal plain lake water budgets

USGS Publications Warehouse

Koch, Joshua C.

2016-01-01

Arctic thaw lakes are an important source of water for aquatic ecosystems, wildlife, and humans. Many recent studies have observed changes in Arctic surface waters related to climate warming and permafrost thaw; however, explaining the trends and predicting future responses to warming is difficult without a stronger fundamental understanding of Arctic lake water budgets. By measuring and simulating surface and subsurface hydrologic fluxes, this work quantified the water budgets of three lakes with varying levels of seasonal drainage, and tested the hypothesis that lateral and subsurface flows are a major component of the post-snowmelt water budgets. A water budget focused only on post-snowmelt surface water fluxes (stream discharge, precipitation, and evaporation) could not close the budget for two of three lakes, even when uncertainty in input parameters was rigorously considered using a Monte Carlo approach. The water budgets indicated large, positive residuals, consistent with up to 70% of mid-summer inflows entering lakes from lateral fluxes. Lateral inflows and outflows were simulated based on three processes; supra-permafrost subsurface inflows from basin-edge polygonal ground, and exchange between seasonally drained lakes and their drained margins through runoff and evapotranspiration. Measurements and simulations indicate that rapid subsurface flow through highly conductive flowpaths in the polygonal ground can explain the majority of the inflow. Drained lakes were hydrologically connected to marshy areas on the lake margins, receiving water from runoff following precipitation and losing up to 38% of lake efflux to drained margin evapotranspiration. Lateral fluxes can be a major part of Arctic thaw lake water budgets and a major control on summertime lake water levels. Incorporating these dynamics into models will improve our ability to predict lake volume changes, solute fluxes, and habitat availability in the changing Arctic.

77 FR 58204 - International Joint Commission Invites Public Comment on Upper Great Lakes Report via...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-19

... of its International Upper Great Lakes Study Board, Lake Superior Regulation: Addressing Uncertainty... for comments has also been extended to September 30, 2012. The Study examines whether the regulation of outflows from Lake Superior through the compensating works and power dams on the St. Marys River...

Climate-driven changes in riverine inputs affecting the stoichiometry of Earth's largest lake

NASA Astrophysics Data System (ADS)

Sterner, R.; Small, G. E.

2014-12-01

Lake Superior, Earth's largest lake by area, has seen a steady increase in nitrate levels over the past century, while phosphorus remains exceedingly low, resulting in an increasingly imbalanced stoichiometry. Although its ratio of watershed area:lake area is relatively small, rivers emptying into Lake Superior could be important drivers of long-term changes in lake stoichiometry. To better assess how the Lake Superior watershed affects its stoichiometry, we examined the chemistry of two of its largest tributaries, the Saint Louis River and the Nipigon River, at their confluences with Lake Superior. Both of these rivers have high dissolved organic carbon (DOC) but low nitrate (NO3) concentrations relative to the lake. Using simple mixing models, we found these nearshore confluences to create sinks of lake NO3 as a result of relatively high rates of denitrification. Climate change is altering the amounts and patterns of delivery of materials from land to lakes and we also examined the plume from a June, 2012 100-year flood in the Saint Louis River. Three days after this historic rain event, we found elevated chlorophyll levels throughout the plume, up to 5-fold higher than in the open lake. Combining our samples with satellite imagery, we conservatively estimate that this plume contained 598,000 kg of phosphorus in dissolved and particulate form, or 40% of the average annual P input to the lake. If storm events such as this occur with increasing frequency as predicted in climate change scenarios, the lake's productivity may increase and stoichiometry could become more balanced, through greater P input and increased N retention due to sedimentation and denitrification.

Hydrologic variability and the application of Index of Biotic Integrity metrics to wetlands: a Great Lakes evaluation

USGS Publications Warehouse

Wilcox, Douglas A.; Meeker, James E.; Hudson, Patrick L.; Armitage, Brian J.; Black, M. Glen; Uzarski, Donald G.

2002-01-01

Interest by land-management and regulatory agencies in using biological indicators to detect wetland degradation, coupled with ongoing use of this approach to assess water quality in streams, led to the desire to develop and evaluate an Index of Biotic Integrity (IBI) for wetlands that could be used to categorize the level of degradation. We undertook this challenge with data from coastal wetlands of the Great Lakes, which have been degraded by a variety of human disturbances. We studied six barrier beach wetlands in western Lake Superior, six drowned-river-mouth wetlands along the eastern shore of Lake Michigan, and six open shoreline wetlands in Saginaw Bay of Lake Huron. Plant, fish, and invertebrate communities were sampled in each wetland. The resulting data were assessed in various forms against gradients of human disturbance to identify potential metrics that could be used in IBI development. Our results suggested that the metrics proposed as potential components of an IBI for barrier beach wetlands of Lake Superior held promise. The metrics for Lake Michigan drowned-river-mouth wetlands were inconsistent in identifying gradients of disturbance; those for Lake Huron open embayment wetlands were yet more inconsistent. Despite the potential displayed by the Lake Superior results within the year sampled, we concluded that an IBI for use in Great Lakes wetlands would not be valid unless separate scoring ranges were derived for each of several sequences of water-level histories. Variability in lake levels from year to year can produce variability in data and affect the reproducibility of data collected, primarily due to extreme changes in plant communities and the faunal habitat they provide. Substantially different results could be obtained in the same wetland in different years as a result of the response to lake-level change, with no change in the level of human disturbance. Additional problems included limited numbers of comparable sites, potential lack of

A coupled lake-atmosphere model (CLAM) and its application to Lake Kinneret