Measurements of Benthic Macroinvertebrate Standing Crop from the Canadian Continental Shelf and Slope of Southern Davis Strait and Ungava Bay

1983 ◽  
Vol 40 (5) ◽  
pp. 652-657 ◽  
Author(s):  
Patrick L. Stewart
Keyword(s):  
Continental Shelf ◽  
North American ◽  
Standing Crop ◽  
Benthic Macroinvertebrate ◽  
Baffin Island ◽  
Medium Sand ◽  
Grand Banks ◽  
Sediment Content ◽  
Davis Strait

Benthic macroinvertebrate standing crop at 14 stations on the Canadian continental shelf, southeast of Baffin Island, ranged from 19.8 to 479.9 g/m2 and was about the same size for given depths, as reported for the Grand Banks of Newfoundland, and higher than reported in more southerly portions of the eastern North American continental shelf. Standing crop was correlated negatively with depth and sediment content of both fine and medium sand.

Blood protozoans of fish from the Davis Strait in the northwestern Atlantic Ocean

1991 ◽  
Vol 69 (2) ◽  
pp. 410-413 ◽  
Author(s):  
R. A. Khan ◽  
E. M. Lee ◽  
W. S. Whitty
Keyword(s):  
Atlantic Ocean ◽  
Fish Species ◽  
The Other ◽  
Baffin Island ◽  
Grand Banks ◽  
Northern Latitudes ◽  
Davis Strait ◽  
Reinhardtius Hippoglossoides ◽  
Raja Radiata ◽  
Hippoglossoides Platessoides

A study was carried out to determine the occurrence and prevalence of blood protozoans in benthic marine fish from the Davis Strait, an area between Baffin Island and Greenland (61–70°N, 53–63°W) in the northwestern Atlantic Ocean. Parasites were seen in all 17 species offish examined; piroplasms were most prevalent (78% of 413), infecting all fish species. Prevalences of infection were substantially lower for trypanosomes (23%) and haemogregarines (4%), both of which infected only 10 and 6 of the fish species, respectively. Prevalences were greater in 5 of the fish species examined, Reinhardtius hippoglossoides, Hippoglossoides platessoides, Lycodes lavalaei, Macrourus berglax, and Raja radiata, than in the other 12 species. Though the prevalence of trypanosomes decreased considerably in the most northerly of three areas, no differences were apparent for piroplasms. Prevalences noted in this paper are comparable to those observed in fish taken off the coast of Labrador but considerably greater than those of the Grand Banks or in areas south of latitude 50°N. Based on occurrence and prevalence, it is likely that fish haematozoans and their leech vectors originated in the northern latitudes and radiated southwards.

scholarly journals Seasonal trends and phenology shifts in sea surface temperature on the North American northeastern continental shelf

Elem Sci Anth ◽  
2017 ◽  
Vol 5 ◽  
Author(s):  
Andrew C. Thomas ◽  
Andrew J. Pershing ◽  
Kevin D. Friedland ◽  
Janet A. Nye ◽  
Katherine E. Mills ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Continental Shelf ◽  
Sea Surface Temperature ◽  
North American ◽  
Gulf Of Maine ◽  
Sea Surface ◽  
Scotian Shelf ◽  
Seasonal Differences ◽  
Study Region ◽  
The North

The northeastern North American continental shelf from Cape Hatteras to the Scotian Shelf is a region of globally extreme positive trends in sea surface temperature (SST). Here, a 33-year (1982–2014) time series of daily satellite SST data was used to quantify and map spatial patterns in SST trends and phenology over this shelf. Strongest trends are over the Scotian Shelf (>0.6°C decade–1) and Gulf of Maine (>0.4°C decade–1) with weaker trends over the inner Mid-Atlantic Bight (~0.3°C decade–1). Winter (January–April) trends are relatively weak, and even negative in some areas; early summer (May–June) trends are positive everywhere, and later summer (July–September) trends are strongest (~1.0°C decade–1). These seasonal differences shift the phenology of many metrics of the SST cycle. The yearday on which specific temperature thresholds (8° and 12°C) are reached in spring trends earlier, most strongly over the Scotian Shelf and Gulf of Maine (~ –0.5 days year–1). Three metrics defining the warmest summer period show significant trends towards earlier summer starts, later summer ends and longer summer duration over the entire study region. Trends in start and end dates are strongest (~1 day year–1) over the Gulf of Maine and Scotian Shelf. Trends in increased summer duration are >2.0 days year–1 in parts of the Gulf of Maine. Regression analyses show that phenology trends have regionally varying links to the North Atlantic Oscillation, to local spring and summer atmospheric pressure and air temperature and to Gulf Stream position. For effective monitoring and management of dynamically heterogeneous shelf regions, the results highlight the need to quantify spatial and seasonal differences in SST trends as well as trends in SST phenology, each of which likely has implications for the ecological functioning of the shelf.

Early Tertiary basalts from the Labrador Sea floor and Davis Strait region

1989 ◽  
Vol 26 (5) ◽  
pp. 956-968 ◽  
Author(s):  
D. B. Clarke ◽  
B. I. Cameron ◽  
G. K. Muecke ◽  
J. L. Bates
Keyword(s):  
Volcanic Rocks ◽  
Labrador Sea ◽  
Baffin Island ◽  
Nd Isotope ◽  
Sea Floor ◽  
West Greenland ◽  
Depleted Mantle ◽  
Davis Strait ◽  
Isotope Systematics ◽  
Seawater Exchange

Fine- to medium-grained, phyric and aphyric basalt samples from ODP Leg 105, site 647A, in the Labrador Sea show little evidence of alteration. Chemically, these rocks are low-potassium (0.01–0.09 wt.% K2O), olivine- to quartz-normative tholeiites that compare closely with the very depleted terrestrial Paleocene volcanic rocks in the Davis Strait region of Baffin Island and West Greenland. However, differences exist in the Sr–Nd isotope systematics of the two suites; the Labrador Sea samples have ε Nd values (+9.3) indicative of a more depleted source, and are higher in 87Sr/86Sr (0.7040), relative to the Davis Strait basalts (ε Nd +2.54 to +8.97; mean 87Sr/86Sr 0.7034). The higher 87Sr/86Sr in the Labrador Sea samples may reflect seawater exchange despite no petrographic evidence for significant alteration. The Labrador Sea and early Davis Strait basalts may have been derived from a similar depleted mantle source composition; however, the later Davis Strait magmas were generated from a different mantle. None of the Baffin Island, West Greenland, or Labrador Sea samples show unequivocal geochemical evidence for contamination with continental crust.

The effect of thermal effluent, before and after macrophyte harvesting, on standing crop and species composition of benthic macroinvertebrate communities in Lake Wabamun, Alberta

1982 ◽  
Vol 60 (12) ◽  
pp. 3196-3205 ◽  
Author(s):  
Joseph B. Rasmussen
Keyword(s):  
Species Composition ◽  
Benthic Macroinvertebrates ◽  
Standing Crop ◽  
Tubifex Tubifex ◽  
Benthic Macroinvertebrate ◽  
Macroinvertebrate Communities ◽  
Plant Detritus ◽  
Chironomid Species ◽  
Before And After ◽  
Heated Area

The heated area of Lake Wabamun prior to macrophyte harvesting had higher submerged macrophyte production, greater amounts of plant detritus in the sediment, and a higher standing crop of benthic macroinvertebrates than the unheated area. Species composition of the benthic macroinvertebrate community was also much different in the heated area with the warmest areas supporting a community dominated by tubificid oligochaetes (Limnodrilus hoffmeisteri and Tubifex tubifex), and the moderately heated areas supporting a community dominated by large Chironomus species (Chironomus plumosus and Chironomus atroviridis). Benthos of the unheated parts of the lake consisted mainly of smaller chironomid species such as Chironomus maturus, C. (cf.) staegeri, Polypedilum nubeculosum, Cladotanytarsus spp., and Tanytarsus spp. The heated area was subjected to mechanical macrophyte harvesting which removed the majority of the submerged macrophytes. This reduced the amount of plant detritus within the sediment and also the standing crop of benthic macroinvertebrates in the heated area. Species composition of the oligochaete-dominated community was not affected by harvesting. Species composition of the Chironomus-dominated area was greatly affected by harvesting and became more similar to that of the unheated area; densities of the large Chironomus species were reduced to low levels, while the densities of smaller chironomid species increased.

Tertiary basalts of western Davis Strait: bedrock core samples and geophysical data

1978 ◽  
Vol 15 (5) ◽  
pp. 773-780 ◽  
Author(s):  
B. MacLean ◽  
R. K. H. Falconer ◽  
D. B. Clarke
Keyword(s):  
Magnetic Anomaly ◽  
Seismic Reflection ◽  
Volcanic Rocks ◽  
Geophysical Data ◽  
Baffin Island ◽  
Main Area ◽  
Fine Grained ◽  
Core Samples ◽  
Davis Strait ◽  
Island Shelf

Short bedrock cores of basalt were recovered at two localities on the Baffin Island shelf, 33 and 89 km southeast of Cape Dyer. The volcanic rocks underlying these sites have a surface extent of some 8000 km2 as outlined by seismic reflection and magnetic anomaly profiles. Similar rocks are inferred to occur at two smaller offshore areas south of the main area. The offshore occurrences are both more continuous and much larger than the onshore basalt areas of eastern Baffin Island.The core samples appear to have been cut from single flows consisting of fine-grained microporphyritic basalts with olivine as the principal phenocryst phase. Although having distinct differences from one another in terms of texture and degree of alteration, the samples from the three drill stations bear similarities to the Baffin Island basalts that suggest a close petrogenetic relationship may exist between the onshore and offshore basalts. However, in contrast to the subaqueously erupted volcanic breccias of onshore Baffin Island and West Greenland the offshore samples contain little evidence of glass, suggesting the possibility that the latter may have been erupted in a subaerial environment.

scholarly journals Pre-Wisconsin stratigraphy and paleoclimates off Atlantic Canada, and its bearing on glaciation in Québec

2010 ◽  
Vol 31 (1-2) ◽  
pp. 15-22 ◽  
Author(s):  
M. Alam ◽  
D. J. W. Piper
Keyword(s):  
Continental Shelf ◽  
Ice Sheet ◽  
Atlantic Canada ◽  
Shelf Edge ◽  
Glacial History ◽  
Grand Banks

Cores from tops of seamounts close to the continental shelf west of the Grand Banks contain sequences of alternating clays (representing glacials) and foram nanno ooze (deposited in warmer periods), back to the Pliocene. Although sedimentation in the cores is controlled primarily by glacial conditions on the Grand Banks and Laurentian Channel, glacial history further inland can be inferred. The Wisconsin sequence shows two cool interstadials and one rather warmer one, correlable with the Plum Point, Port Talbot and St. Pierre Interstadials. Clay sedimentation during Wisconsin glacial stages was minor, suggesting glaciers did not extend to the shelf edge. In the late lllinoian, there was a major influx of red sediments, indicating significant erosion of the Gulf of St. Lawrence and Laurentian Channel. Glaciation was more extensive than during the Wisconsin. Two lllinoian interstadials, with temperatures between those of the Plum Point and St. Pierre interstadials are recognised. Early lllinoian glaciation was the most severe yet recognised in the cores. Sedimentation appears to have been controlled by the advance of a Newfoundland — Labrador — E. Québec ice sheet across the Grand Banks.

scholarly journals A photographic atlas of the eastern Canadian Continental Shelf: Scotian Shelf, Grand Banks of Newfoundland

1989 ◽  
Author(s):  
P Lawrence ◽  
K W Strong ◽  
P Pocklington ◽  
P L Stewart ◽  
G B J Fader
Keyword(s):  
Continental Shelf ◽  
Scotian Shelf ◽  
Grand Banks

scholarly journals Recent Foraminifera from the North Sea (Forties and Ekofisk areas) and the continental shelf west of Scotland

1985 ◽  
Vol 4 (2) ◽  
pp. 117-125 ◽  
Author(s):  
John W. Murray
Keyword(s):  
Continental Shelf ◽  
North Sea ◽  
Standing Crop ◽  
High Energy ◽  
The West ◽  
The North ◽  
Energy Environment ◽  
Bottom Waters ◽  
The North Sea ◽  
Northern North Sea

Abstract. The regions studied are all of mid continental shelf depth (70–145 m) and have bottom waters of normal marine salinity. The North Sea has lower bottom water temperatures than those to the west of Scotland. However, the major difference between the two regions is one of tidal and/or wave energy: the northern North Sea is a low energy environment of muddy sand deposition whereas the sampled part of the continental shelf west and north of Scotland is a moderate to high energy environment of medium to coarse biogenic carbonate sedimentation.The physical differences between the two main areas are reflected in the living and dead foraminiferal assemblages. The northern North Sea is a region of free-living species whereas the continental shelf west of Scotland has immobile and mobile attached species living on firm substrates. The northern North Sea is very fertile and has high standing crop values.The dead assemblages are small in size and very abundant. To the west of Scotland the sea is less fertile, standing crop values are low, the dead assemblages are moderate to large in size and reasonably abundant due to the slow rate of dilution by sediment.

Sign in / Sign up

Export Citation Format

Share Document