scholarly journals Interannual variability in phytoplankton blooms and plankton productivity over the Nova Scotian Shelf and in the Gulf of Maine

2011 ◽  
Vol 426 ◽  
pp. 105-118 ◽  
Author(s):  
H Song ◽  
R Ji ◽  
C Stock ◽  
K Kearney ◽  
Z Wang
Keyword(s):  
Interannual Variability ◽  
Gulf Of Maine ◽  
Phytoplankton Blooms ◽  
Scotian Shelf ◽  
Nova Scotian

scholarly journals Modeling the influence of low-salinity water inflow on winter-spring phytoplankton dynamics in the Nova Scotian Shelf–Gulf of Maine region

2008 ◽  
Vol 30 (12) ◽  
pp. 1399-1416 ◽  
Author(s):  
Rubao Ji ◽  
Cabell S. Davis ◽  
Changsheng Chen ◽  
David W. Townsend ◽  
David G. Mountain ◽  
...  
Keyword(s):  
Gulf Of Maine ◽  
Water Inflow ◽  
Phytoplankton Dynamics ◽  
Scotian Shelf ◽  
Low Salinity ◽  
Low Salinity Water ◽  
Salinity Water ◽  
Nova Scotian

Annual and interannual variability of nutrients and their estimated fluxes in the Scotian Shelf - Gulf of Maine region

2000 ◽  
Vol 57 (12) ◽  
pp. 2536-2546 ◽  
Author(s):  
Brian Petrie ◽  
Philip Yeats
Keyword(s):  
Dissolved Oxygen ◽  
Interannual Variability ◽  
Gulf Of Maine ◽  
Primary Source ◽  
Late Winter ◽  
Scotian Shelf ◽  
Annual Cycles ◽  
Deep Layers ◽  
Annual And Interannual Variability ◽  
Diffusive Fluxes

Nitrate, silicate, and phosphate observations are used to determine their annual cycles for the Scotian Shelf and the Gulf of Maine. Concentrations increase from fall through winter, decrease rapidly at shallow depths in late winter, and remain at low levels through spring and summer. Deep layers exhibit a weak annual cycle with highest concentrations in summer. Winter nitrate concentrations (depth [Formula: see text] 50 m) are highest on the eastern Scotian Shelf, decreasing southwestwards into the Gulf of Maine. The Gulf of St. Lawrence is the primary source of nitrate (9300 mol· s-1) and silicate (7680 mol·s-1) during winter for the Scotian Shelf; in spring and summer, vertical diffusive fluxes, 1500-1000 mol·s-1 for the central Scotian Shelf, are as large as the horizontal advective ones and can provide the entire nitrate requirement. The 50-m vertical diffusive fluxes of nitrate and silicate vary by a factor of 4 in the Scotian Shelf - Gulf of Maine region. The interannual variability of nitrate and dissolved oxygen on the Scotian Shelf are coupled to water mass changes, with low (high) nitrate and high (low) dissolved oxygen concentrations corresponding to the dominance of Labrador (Warm) Slope water.

scholarly journals Surveys of larval sealworm (Pseudoterranova decipiens) infection in various fish species sampled from Nova Scotian waters between 1988 and 1996, with an assessment of examination procedures

2001 ◽  
Vol 3 ◽  
pp. 57 ◽  
Author(s):  
G McClelland ◽  
DJ Martell
Keyword(s):  
Gadus Morhua ◽  
Gulf Of Maine ◽  
New Host ◽  
Pseudoterranova Decipiens ◽  
Infection Parameters ◽  
Routine Inspection ◽  
Frozen Fish ◽  
Nova Scotian ◽  
New Host Records ◽  
Benthic Consumers

Between November 1988 and October 1996, >10,000 fish from the Breton Shelf, Sable Island Bank and the northeastern Gulf of Maine were examined for larval anisakines. Larval sealworm, Pseudoterranova decipiens, occurred in 30 of 39 species surveyed, including 8 new host records, Enchelyopus cimbrius, Lycodes reticulatus, Eumesogrammus praecisus, Lumpenus lumpretaeformis, Lumpenus maculatus, Cryptacanthodes maculatus, Artediellus atlanticus and Triglops murrayi. The parasite was most prevalent and abundant in mature demersal piscivores and benthic consumers. Sealworm densities (nr kg-1 host wt.), however, were greatest in small benthophagous fish including mature E. cimbrius, A. atlanticus, T. murrayi and Aspidophoroides monopterygius, and juvenile Hippoglossoides platessoides. ANOVA revealed that geographical disparities in sealworm prevalence and abundance were highly significant in 14 of 20 species tested, although significant disparities between samples from each of the three areas were evident only in H. platessoides. Almost invariably, infection parameters were greatest in fish from Sable Island Bank. ANOVA also indicated that sealworm prevalence and/or abundance increased significantly in Sable Island Bank populations of Gadus morhua, H. platessoides, and seven other species between 1985-1986 and 1989-1990. Routine examinations, in which host flesh was sliced and candled, proved as efficacious as digestion in warm (35° C) pepsin-HCl for detection of larval sealworm in the flesh of large frozen fish. Procedures employing fresh (iced) samples, digestion at ambient temperature and microscopy are recommended, however, for surveys of small benthic consumers. Many of the sealworm infecting the latter hosts are tiny (2 to 10 mm in length) nematodes, which escape detection by routine inspection, and may not survive in warm pepsin-HCl solution.

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.

scholarly journals Diagnosing transit times on the northwestern North Atlantic continental shelf

2018 ◽  
Author(s):  
Krysten Rutherford ◽  
Katja Fennel
Keyword(s):  
North Atlantic ◽  
Gulf Of Maine ◽  
Circulation Model ◽  
Shelf Break ◽  
Genetic Connectivity ◽  
Western Boundary ◽  
Coastal Current ◽  
Scotian Shelf ◽  
Grand Banks ◽  
Transit Times

Abstract. The circulation in the northwestern North Atlantic Ocean is highly complex, characterized by the confluence of two major western boundary current systems and several shelf currents. Here we present the first comprehensive analysis of transport paths and timescales for the northwestern North Atlantic shelf, which is useful for estimating ventilation rates, describing circulation and mixing, characterizing the composition of water masses with respect to different source regions, and elucidating rates and patterns of biogeochemical processing, species dispersal and genetic connectivity. Our analysis uses dye and age tracers within a high-resolution circulation model of the region, divided into 9 sub-regions, to diagnose retention times, transport pathways, and transit times. Retention times are shortest on the Scotian Shelf (~ 3 months) where the inshore and shelf-break branches of the coastal current system result in high along-shelf transport to the southwest. Larger retention times are simulated on the Grand Banks (~ 4 months), in the Gulf of St. Lawrence (~ 12 months) and the Gulf of Maine (~ 6 months). Source water analysis shows that Scotian Shelf water is primarily comprised of waters from the Grand Banks and Gulf of St. Lawrence, with varying composition across the shelf. Contributions from the Gulf of St. Lawrence are larger at near-shore locations, whereas locations near the shelf break have larger contributions from the Grand Banks and slope waters. Waters from the deep slope have little connectivity with the shelf, because the shelf-break current inhibits transport across the shelf break. Grand Banks and Gulf of St. Lawrence waters are therefore dominant controls on biogeochemical properties, and on setting and sustaining planktonic communities on the Scotian Shelf.

Advancing an Ecosystem Approach in the Gulf of Maine

2012 ◽  
Keyword(s):  
Large Scale ◽  
Gulf Of Maine ◽  
Critical Role ◽  
Monitoring Program ◽  
Ecosystem Dynamics ◽  
Georges Bank ◽  
Scotian Shelf ◽  
Monitoring Programs ◽  
Zooplankton Dynamics ◽  
Biological Environment

<i>Abstract</i>.—Zooplankton communities perform a critical role as secondary producers in marine ecosystems. They are vulnerable to climate-induced changes in the marine environment, including temperature, stratification, and circulation, but the effects of these changes are difficult to discern without sustained ocean monitoring. The physical, chemical, and biological environment of the Gulf of Maine, including Georges Bank, is strongly influenced by inflow from the Scotian Shelf and through the Northeast Channel, and thus observations both in the Gulf of Maine and in upstream regions are necessary to understand plankton variability and change in the Gulf of Maine. Large-scale, quasi synoptic plankton surveys have been performed in the Gulf of Maine since Bigelow’s work at the beginning of the 20th century. More recently, ongoing plankton monitoring efforts include Continuous Plankton Recorder sampling in the Gulf of Maine and on the Scotian Shelf, U.S. National Marine Fisheries Service’s MARMAP (Marine Resources Monitoring, Assessment, and Prediction) and EcoMon (Ecosystem Monitoring) programs sampling the northeast U.S. Continental Shelf, including the Gulf of Maine, and Fisheries and Oceans Canada’s Atlantic Zone Monitoring Program on the Scotian Shelf and in the eastern Gulf of Maine. Here, we review and compare past and ongoing zooplankton monitoring programs in the Gulf of Maine region, including Georges Bank and the western Scotian Shelf, to facilitate retrospective analysis and broadscale synthesis of zooplankton dynamics in the Gulf of Maine. Additional sustained sampling at greater-than-monthly frequency at selected sites in the Gulf of Maine would be necessary to detect changes in phenology (i.e. seasonal timing of biological events). Sustained zooplankton sampling in critical nearshore fish habitats and in key feeding areas for upper trophic level organisms, such as marine mammals and seabirds, would yield significant insights into their dynamics. The ecosystem dynamics of the Gulf of Maine are strongly influenced by large-scale forcing and variability in upstream inflow. Improved coordination of sampling and data analysis among monitoring programs, effective data management, and use of multiple modeling approaches will all enhance the mechanistic understanding of the structure and function of the Gulf of Maine pelagic ecosystem.

Description and Distribution of New Specimens of the Fish Lipogenys gilli from the Western North Atlantic

1973 ◽  
Vol 30 (10) ◽  
pp. 1559-1564 ◽  
Author(s):  
Wilfred Templeman
Keyword(s):  
Continental Slope ◽  
North Atlantic ◽  
Standard Length ◽  
Single Specimen ◽  
Scotian Shelf ◽  
Vertebral Number ◽  
Rare Fish ◽  
Nova Scotian

Nine specimens of the rare fish Lipogenys gilli Goode and Bean, 1895, previously known from a single specimen taken off Maryland in 1887, were taken between 1957 and 1970 along the continental slope of the Nova Scotian Shelf to southwestern Grand Bank, at depths of about 400–800 m. These specimens, 238–375 mm in standard length, have a remarkably low variation in vertebral number (228–234). From the additional specimens the description of the species is considerably extended.

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