A Model Study of the Buoyancy-Driven Circulation in the Gulf of Maine

Brooks, David A.

doi:10.1175/1520-0485(1994)024<2387:amsotb>2.0.co;2

Cited by 39 publications

(41 citation statements)

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“…At this point the current branches into two segments, one that continues along the coast and another that veers offshore around the Jordan Basin Gyre. Potential mechanisms affecting the path of this offshore branch include topographic effects, offshore steering along the southwestern flank of the cyclonic gyre over Jordan Basin (Bisagni et al, 1996;Brooks and Townsend, 1989), and inshore influences of the Penobscot river plume that tend to push the current offshore (Brooks, 1994;Pettigrew et al, 1998;Xue et al, 2000). The Western segment of the MCC is fed by the inshore branch of the eastern segment together with the outflow of the Penobscot River.…”

Section: Circulation Modelmentioning

confidence: 99%

Mechanisms regulating large-scale seasonal fluctuations in Alexandrium fundyense populations in the Gulf of Maine: Results from a physical–biological model

McGillicuddy

Anderson

Lynch

et al. 2005

Deep Sea Research Part II: Topical Studies in Oceanography

148

132

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Observations of Alexandrium fundyense in the Gulf of Maine indicate several salient characteristics of the vegetative cell distributions: patterns of abundance are gulf-wide in geographic scope; their main features occur in association with the Maine Coastal Current; and the center of mass of the distribution shifts upstream from west to east during the growing season from April to August. The mechanisms underlying these aspects are investigated using coupled physical-biological simulations that represent the population dynamics of A. fundyense within the seasonal mean flow. A model that includes germination, growth, mortality, and nutrient limitation is qualitatively consistent with the observations. Germination from resting cysts appears to be a key aspect of the population dynamics that confines the cell distribution near the coastal margin, as simulations based on a uniform initial inoculum of vegetative cells across the Gulf of Maine produces blooms that are broader in geographic extent than is observed. In general, cells germinated from the major cyst beds (in the Bay of Fundy and near Penobscot and Casco Bays) are advected in the alongshore direction from east to west in the coastal current. Growth of the vegetative cells is limited primarily by temperature from April through June throughout the gulf, whereas nutrient limitation occurs in July and August in the western gulf. Thus the seasonal shift in the center of mass of cells from west to east can be explained by changing growth conditions: growth is more rapid in the western gulf early in the season due to warmer temperatures, whereas growth is more rapid in the eastern gulf later in the season due to severe nutrient limitation in the western gulf during that time period. A simple model of encystment based on nutrient limitation predicts deposition of new cysts in the vicinity of the observed cyst bed offshore of Casco and Penobscot Bays, suggesting a pathway of re-seeding the bed from cells advected downstream in the coastal current. A retentive gyre at the mouth of the Bay of Fundy tends to favor re-seeding that cyst bed from local populations.

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Section: Circulation Modelmentioning

confidence: 99%

Mechanisms regulating large-scale seasonal fluctuations in Alexandrium fundyense populations in the Gulf of Maine: Results from a physical–biological model

McGillicuddy

Anderson

Lynch

et al. 2005

Deep Sea Research Part II: Topical Studies in Oceanography

148

132

View full text Add to dashboard Cite

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“…Recent numerical studies by Brooks [1994] We present here hydrographic and nutrient data from survey transects across several prominent cold plume features, extending from the EMCC into the interior of the eastern Gulf of Maine, that appeared in AVHRR imagery of the Gulf of Maine on May 11, 1994. Principal objectives of the work were to document the subsurface structure of these features, to estimate the associated nitrate flux from the coastal region into the interior of the Gulf of Maine, and to determine to what extent plume waters may be entrained into the cyclonic circulation of the Jordan Basin Gyre.…”

Section: 625mentioning

confidence: 99%

Observations of the Eastern Maine Coastal Current and its offshore extensions in 1994

Pettigrew¹,

Townsend²,

Xue³

et al. 1998

J. Geophys. Res.

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Abstract.Cold surface temperatures, reflecting Scotian Shelf origins and local tidal mixing, serve as a tracer of the Eastern Maine Coastal Current and its offshore extensions, which appear episodically as cold plumes erupting from the eastern Maine shelf. A cold water plume emanating from the Eastern Maine Coastal Current in May 1994 was investigated using advanced very high resolution radiometer (AVHRR) imagery, shipboard surveys of physical and biochemical properties, and satellite-tracked drifters. Evidence is presented that suggests that some of the plume waters were entrained within the cyclonic circulation over Jordan Basin, while the major portion participated in an anticyclonic eddy at the distal end of the plume. Calculations of the nitrate transported offshore by the plume show that this feature can episodically export significant quantities of nutrients from the Eastern Maine Coastal Current to offshore regions that are generally nutrient depleted during spring-summer. A series of AVHRR images is used to document the seasonal along-shelf progression of the coastal plume separation point. We speculate on potential causes and consequences of plume separation from the coastal current and suggest that this feature may be an important factor influencing the patterns and overall biological productivity of the eastern Gulf of Maine.

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“…and +0.5 PSU in 1993 and1994). This has been attributed, at least in part, to elevated vertical mixing due to sharp variations in the depths of the models sigma layers over regions of steep topography .…”

Section: The Physical and Nutrient Modelmentioning

confidence: 97%

“…This feature, referred to as the Maine Coastal Current (MCC), is characterized by a series of segments and branch points . The direction of flow at the branch points is modulated by a diverse set of factors including wind, river input, bathymetric effects, and the strength of the geopotential low that generally forms over Jordan ,Basin in response to dense slope water in its interior (Brooks and Townsend, 1989, Brooks, 1994. A.…”

Section: The Gulf Of Maine Pig 1) Is a Continental Shelf Sea Separatmentioning

confidence: 99%

Blooms of the toxic dinoflagellate Alexandrium fundyense in the Gulf of Maine : investigations using physical-biological model

Stock¹

2005

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A Model Study of the Buoyancy-Driven Circulation in the Gulf of Maine

Cited by 39 publications

References 0 publications

Mechanisms regulating large-scale seasonal fluctuations in Alexandrium fundyense populations in the Gulf of Maine: Results from a physical–biological model

Mechanisms regulating large-scale seasonal fluctuations in Alexandrium fundyense populations in the Gulf of Maine: Results from a physical–biological model

Observations of the Eastern Maine Coastal Current and its offshore extensions in 1994

Blooms of the toxic dinoflagellate Alexandrium fundyense in the Gulf of Maine : investigations using physical-biological model

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