Geology and paleoecology of a Middle Wisconsin fossil occurrence in Zorra Township, southwestern Ontario, Canada

2015 ◽  
Vol 52 (6) ◽  
pp. 386-404 ◽  
Author(s):  
A.F. Bajc ◽  
P.F. Karrow ◽  
C.H. Yansa ◽  
B.B. Curry ◽  
Jeffrey C. Nekola ◽  
...  
Keyword(s):  
Great Lakes ◽  
Late Quaternary ◽  
Plant Macrofossils ◽  
Great Lakes Basin ◽  
Long Distance ◽  
Southern Ontario ◽  
Oxygen Isotope Stage ◽  
Fossil Assemblage ◽  
Long Distance Transport ◽  
Organic Deposit

Nonglacial deposits of Middle Wisconsin age are being discovered with increased frequency across a broad region of southern Ontario, Canada, and provide strong evidence for a time of significant ice withdrawal from the lower Great Lakes region. With each new discovery, a refined understanding of regional climatic and paleoecological environments is emerging. In this paper, we present the results of a sedimentological and paleoecological study of a subtill organic deposit in Zorra Township, southwestern Ontario. The organic deposit, which lies beneath Nissouri Phase Catfish Creek Till (Late Wisconsin), has been dated by accelerator mass spectrometry at between 50.5 and 42.9 14C ka BP. The organic remains are contained within slack water pond deposits infilling a channel incised into till either of Early Wisconsin or Illinoian age. The fossil assemblage appears to be strongly influenced by taphonomic processes, including degradation due to oxidation, bacterial and fungal decay, and glacial overriding. Reworking and (or) recycling and selective sorting as well as long-distance transport has also influenced the composition of the fossil assemblage preserved. Nonetheless, meaningful paleoecological information is still obtained from this record. Collectively, the pollen and plant macrofossils indicate a boreal-type pine–spruce forest with temperatures cooler than present. The absence of arctic tundra plants, as are found in many other deposits of similar age in the lower Great Lakes basin, is notable. A pond or wetland inhabited by shoreline herbs, shrubs, and trees was present at or proximal to the site. The freshwater mollusc and ostracode assemblages are consistent with a shallow water habitat with dense submerged vegetation. The terrestrial mollusc assemblage suggests a taiga or transitional taiga–tundra fauna. Together, these fossil groups provide one of the most comprehensive environmental reconstructions of Middle Wisconsin time (oxygen isotope stage 3 or OIS3) in southern Ontario and serve to build on the ever-increasing database of paleoecological information accumulating for this episode of the late Quaternary.

scholarly journals Flight simulator system for research and teaching application

2021 ◽  
Author(s):  
Siju Thomas
Keyword(s):  
Hospital Admissions ◽  
The United States ◽  
Long Distance ◽  
Air Contaminants ◽  
Southern Ontario ◽  
Mortality And Morbidity ◽  
Respiratory Illnesses ◽  
Long Distance Transport ◽  
Summer Smog ◽  
Local Contribution

A spatial analysis of smog events in Southern Ontario and prevailing winds reveals various patterns that occur during smog advisories. Smog events cause numerous excess deaths and illnesses each year throughout Southern Ontario due to high levels of air pollutants that are generated in North America. Cardiovascular and respiratory illnesses are the main hospital admissions that occur during summer smog episodes. These effects are experienced throughout regions located along the Windsor-Quebec corridor, but there are variations in the numbers of affected people due to the effects of surrounding geographical features and the local contribution of air contaminants. Meteorological differences play a major role in the effects of smog events with factors such as temperature and prevailing winds. This study examines the effects of long distance transport of contaminants from origins in the United States into Canada as indicated by respiratory and cardiovascular mortality and morbidity effects during 9 smog events. This study found that during certain conditions there is a correlation between wind direction and smog related mortality and morbidity.

scholarly journals Ancient Lake Maxima and Substrate-dependent Riverine Migration Have Defined the Range of the Mudpuppy (Necturus maculosus) in Southern Ontario Following the Wisconsinan Glaciation

2016 ◽  
Vol 130 (2) ◽  
pp. 158 ◽  
Author(s):  
Peter B Mills ◽  
Duncan J E Hill
Keyword(s):  
Great Lakes ◽  
Geographic Range ◽  
Limiting Factor ◽  
Ancient Lake ◽  
Flow Conditions ◽  
Great Lakes Basin ◽  
Southern Ontario ◽  
Necturus Maculosus ◽  
Outlet Flow ◽  
Nipissing Phase

The Mudpuppy (Necturus maculosus) is an entirely aquatic salamander whose geographic range is thus defined by immigration routes in watersheds that permit feasible travel. Significant barriers, such as large waterfalls, effectively bar this species from further colonization upstream. We compared the contemporary distribution of Mudpuppies in southern Ontario with varying post-glacial ancient lake maxima and riverine outlet-flow conditions. Topography does not appear to be a range-limiting factor, but the type of river grade (waterfalls versus riffles) does. The distribution of modern records of this species in Ontario aligns closely with maxima from the Nipissing phase occurring 4000–5000 years ago, leading us to suggest that this is when Mudpuppies invaded and proliferated in the Great Lakes Basin.

scholarly journals Transport of the Harmful Bloom Alga Aureococcus anophagefferens by Oceangoing Ships and Coastal Boats

2004 ◽  
Vol 70 (11) ◽  
pp. 6495-6500 ◽  
Author(s):  
Martina A. Doblin ◽  
Linda C. Popels ◽  
Kathryn J. Coyne ◽  
David A. Hutchins ◽  
S. Craig Cary ◽  
...  
Keyword(s):  
Great Lakes ◽  
Ballast Water ◽  
Harmful Algal Bloom ◽  
Brown Tide ◽  
Phytoplankton Species ◽  
Aureococcus Anophagefferens ◽  
Long Distance ◽  
Active Growth ◽  
Ballast Tank ◽  
Long Distance Transport

ABSTRACT It is well established that cyst-forming phytoplankton species are transported in ships' ballast tanks. However, there is increasing evidence that other phytoplankton species which do not encyst are also capable of surviving ballast transit. These species have alternative modes of nutrition (hetero- or mixotrophy) and/or are able to survive long-term darkness. In our studies of no-ballast-on-board vessels arriving in the Great Lakes, we tested for the presence of the harmful algal bloom species Aureococcus anophagefferens (brown tide) in residual (i.e., unpumpable) ballast water using methods based on the PCR. During 2001, the brown tide organism was detected in 7 of 18 ballast water tanks in commercial ships following transit from foreign ports. Furthermore, it was detected after 10 days of ballast tank confinement during a vessel transit in the Great Lakes, a significant result given the large disparity between the salinity tolerance for active growth of Aureococcus (>22 ppt) and the low salinity of the residual ballast water (∼2 ppt). We also investigated the potential for smaller, recreational vessels to transport and distribute Aureococcus. During the summer of 2002, 11 trailered boats from the inland bays of Delaware and coastal bays of Maryland were sampled. Brown tide was detected in the bilge water in the bottoms of eight boats, as well as in one live-well sample. Commercial ships and small recreational boats are therefore implicated as potential vectors for long-distance transport and local-scale dispersal of Aureococcus.

scholarly journals Environmental stress effects on illness in Southern Ontario

2021 ◽  
Author(s):  
Chelsea Blair LeBlanc
Keyword(s):  
Hospital Admissions ◽  
The United States ◽  
Long Distance ◽  
Southern Ontario ◽  
Mortality And Morbidity ◽  
Respiratory Illnesses ◽  
Stress Effects ◽  
Long Distance Transport ◽  
Summer Smog ◽  
Local Contribution

A spatial analysis of smog events in Southern Ontario and prevailing winds reveals various patterns that occur during smog advisories. Smog events cause numerous excess deaths and illnesses each year throughout Southern Ontario due to high levels of air pollutants that are generated in North America. Cardiovascular and respiratory illnesses are the main hospital admissions that occur during summer smog episodes These effects are experienced throughout regions located along the Windsor-Quebec corridor, but there are variations in the numbers of affected people due to the effects of surrounding geographical features and the local contribution of air contaminants. Meteorological differences play a major role n the effects of smog events with factors such as temperature and prevailing winds. This study examines the effects of long distance transport of contaminants from origins in the United States into Canada as indicated by respiratory and cardiovascular mortality and morbidity effects during 9 smog events. This study found that during certain conditions there is a correlation between wind direction and smog-related mortality and morbidity.

scholarly journals Flight simulator system for research and teaching application

2021 ◽  
Author(s):  
Siju Thomas
Keyword(s):  
Hospital Admissions ◽  
The United States ◽  
Long Distance ◽  
Air Contaminants ◽  
Southern Ontario ◽  
Mortality And Morbidity ◽  
Respiratory Illnesses ◽  
Long Distance Transport ◽  
Summer Smog ◽  
Local Contribution

A spatial analysis of smog events in Southern Ontario and prevailing winds reveals various patterns that occur during smog advisories. Smog events cause numerous excess deaths and illnesses each year throughout Southern Ontario due to high levels of air pollutants that are generated in North America. Cardiovascular and respiratory illnesses are the main hospital admissions that occur during summer smog episodes. These effects are experienced throughout regions located along the Windsor-Quebec corridor, but there are variations in the numbers of affected people due to the effects of surrounding geographical features and the local contribution of air contaminants. Meteorological differences play a major role in the effects of smog events with factors such as temperature and prevailing winds. This study examines the effects of long distance transport of contaminants from origins in the United States into Canada as indicated by respiratory and cardiovascular mortality and morbidity effects during 9 smog events. This study found that during certain conditions there is a correlation between wind direction and smog related mortality and morbidity.

scholarly journals Environmental stress effects on illness in Southern Ontario

2021 ◽  
Author(s):  
Chelsea Blair LeBlanc
Keyword(s):  
Hospital Admissions ◽  
The United States ◽  
Long Distance ◽  
Southern Ontario ◽  
Mortality And Morbidity ◽  
Respiratory Illnesses ◽  
Stress Effects ◽  
Long Distance Transport ◽  
Summer Smog ◽  
Local Contribution

A spatial analysis of smog events in Southern Ontario and prevailing winds reveals various patterns that occur during smog advisories. Smog events cause numerous excess deaths and illnesses each year throughout Southern Ontario due to high levels of air pollutants that are generated in North America. Cardiovascular and respiratory illnesses are the main hospital admissions that occur during summer smog episodes These effects are experienced throughout regions located along the Windsor-Quebec corridor, but there are variations in the numbers of affected people due to the effects of surrounding geographical features and the local contribution of air contaminants. Meteorological differences play a major role n the effects of smog events with factors such as temperature and prevailing winds. This study examines the effects of long distance transport of contaminants from origins in the United States into Canada as indicated by respiratory and cardiovascular mortality and morbidity effects during 9 smog events. This study found that during certain conditions there is a correlation between wind direction and smog-related mortality and morbidity.

Pollen marqueur de transports à longue distance dans l'atmosphère du sud de l'Ontario (Canada)

1992 ◽  
Vol 70 (11) ◽  
pp. 2284-2293 ◽  
Author(s):  
G. Cambon ◽  
J. C. Ritchie ◽  
P. Guinet
Keyword(s):  
Late Quaternary ◽  
Surface Wind ◽  
Source Area ◽  
The United States ◽  
Conclusive Evidence ◽  
Quaternary Sediments ◽  
Long Distance ◽  
Long Distance Transport ◽  
Pollen Transport ◽  
Distance Transport

An analysis of weekly air samples at four sites in southern Ontario (London, Toronto, Peterborough, Sudbury) provides conclusive evidence for the long-distance transport of pollen of the exotic taxa Entada (Mimosaceae), Dodonaea (Sapindaceae), and Ephedra (Ephedraceae), originating far to the south (at least 1000 km) of the recording stations. The nearest source area for the first two taxa is in the West Indies and Mexico, while Ephedra, previously noted in Late Quaternary sediments from the Great Lakes region, grows commonly in the southwestern region of the United States. Long-distance transport is corroborated by air-mass trajectory analysis and surface-wind patterns at time of exotic occurrences. Key words: aeropalynology, Ontario, airstreams, pollen transport.

The Fine Structure of Phloem Cells

1985 ◽  
Vol 43 ◽  
pp. 632-635
Author(s):  
James Cronshaw
Keyword(s):  
Structural Studies ◽  
High Concentration ◽  
Long Distance ◽  
Phloem Tissue ◽  
Sieve Elements ◽  
Long Distance Transport ◽  
P Protein ◽  
Companion Cells ◽  
Electron Microscopical ◽  
Distance Transport

Long distance transport in plants takes place in phloem tissue which has characteristic cells, the sieve elements. At maturity these cells have sieve areas in their end walls with specialized perforations. They are associated with companion cells, parenchyma cells, and in some species, with transfer cells. The protoplast of the functioning sieve element contains a high concentration of sugar, and consequently a high hydrostatic pressure, which makes it extremely difficult to fix mature sieve elements for electron microscopical observation without the formation of surge artifacts. Despite many structural studies which have attempted to prevent surge artifacts, several features of mature sieve elements, such as the distribution of P-protein and the nature of the contents of the sieve area pores, remain controversial.

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