Toxic phytoplankton blooms in the southwestern Gulf of Maine: testing hypotheses of physical control using historical data

Franks, P. J. S.; Anderson, Donald M.

doi:10.1007/bf00349740

Cited by 62 publications

(49 citation statements)

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“…Hydrographic survey data revealed cell populations in the coastal waters with peak concentrations on the order of hundreds to thousands of cells per liter, generally associated with plumes of fresh water emanating from riverine sources (Franks and Anderson, 1992a). In fact, the north-to-south progression of toxicity within the western Gulf of Maine (south of Penobscot Bay) can be explained by alongshore transport of cells in coastally-trapped river plumes (Franks and Anderson, 1992b).…”

Section: Introductionmentioning

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

149

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: Introductionmentioning

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

149

132

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“…In the western GOM, A. fundyense was found to be associated with the warm, lowsalinity buoyant plume originating from western Maine rivers (Franks and Anderson 1992a). Large-scale cruises in the offshore waters of the eastern GOM have shown that A. fundyense is also associated with the cold, nutrient-rich waters of the EMCC (Townsend et al 2001).…”

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confidence: 99%

“…Circulation tends to be counterclockwise (Bigelow 1927;Brooks 1985), with southwestward flow along the coast of Maine toward Massachusetts Bay driven by freshwater inflows from the Scotian Shelf overlying salty slope water input through the Northeast Channel and filling Jordan Basin. This region is also influenced by several rivers emptying into the western GOM that overlie the general circulation and extend southwestward along the coast and sometimes into Massachusetts Bay (Butman 1975;Franks and Anderson 1992a;Geyer et al 1992).…”

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confidence: 99%

“…In the western GOM, the link between the toxic cells and the buoyant coastal plume led to the formulation of a conceptual model for PSP dynamics in the region termed the ''plume advection hypothesis'' (Franks and Anderson 1992a). Critical features of this model include (1) a source population of A. fundyense cells located near the Kennebec River mouth; (2) retention, transport, and growth of those cells in the coastally trapped, buoyant plume formed by outflow from these and other western Maine rivers; and (3) PSP toxicity in nearshore shellfish that relates directly to the alongshore and cross-shore location of the plume and its associated A. fundyense cells.…”

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confidence: 99%

“…Of these factors, wind stress appears to be particularly important in determining transport variability in surface waters (Franks and Anderson 1992a;Fong et al 1997). Downwelling-favorable wind (from the north or northeast) compresses the plume against the coast and accelerates it alongshore, while an upwelling-favorable wind (from the south) flattens the pycnocline slope and thins the low-salinity surface plume as it is moved offshore.…”

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confidence: 99%

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Toxic Alexandrium blooms in the western Gulf of Maine: The plume advection hypothesis revisited

et al. 2005

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The plume advection hypothesis links blooms of the toxic dinoflagellate Alexandrium fundyense in the western Gulf of Maine (GOM) to a buoyant plume derived from river outflows. This hypothesis was examined with cruise and moored-instrument observations in 1993 when levels of paralytic shellfish poisoning (PSP) toxins were high, and in 1994 when toxicity was low. A coupled physical-biological model simulated hydrography and A. fundyense distributions. Initial A. fundyense populations were restricted to low-salinity nearshore waters near Casco Bay, but also occurred in higher salinity waters along the plume boundary. This suggests two sources of cells-those from shallow-water cyst populations and those transported to shore from offshore blooms in the eastern segment of the Maine coastal current (EMCC). Observations confirm the role of the plume in A. fundyense transport and growth. Downwelling-favorable winds in 1993 transported the plume and its cells rapidly alongshore, enhancing toxicity and propagating PSP to the south. In 1994, sustained upwelling moved the plume offshore, resulting in low toxicity in intertidal shellfish. A. fundyense blooms were likely nutrient limited, leading to low growth rates and moderate cell abundances. These observations and mechanisms were reproduced by coupled physical-biological model simulations. The plume advection hypothesis provides a viable explanation for outbreaks of PSP in the western GOM, but should be refined to include two sources for cells that populate the plume and two major pathways for transport: one within the low-salinity plume and another where A. fundyense cells originating in the EMCC are transported along the outer boundary of the plume front with the western segment of the Maine coastal current.Toxic dinoflagellate blooms are a serious economic and

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A Bayesian structural model for predicting algal blooms

Sun

Liu

Wang

2019

Journal of Forecasting

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A Bayesian structural model with two components is proposed to forecast the occurrence of algal blooms, multivariate mean‐reverting diffusion process (MMRD), and a binary probit model with latent Markov regime‐switching process (BPMRS). The model has three features: (a) forecast of the occurrence probability of algal bloom is directly based on oceanographic parameters, not the forecasting of special indicators in traditional approaches, such as phytoplankton or chlorophyll‐a; (b) augmentation of daily oceanographic parameters from the data collected every 2 weeks is based on MMRD. The proposed method solves the problem of unavailability of daily oceanographic parameters in practice; (c) BPMRS captures the unobservable factors which affect algal bloom occurrence and therefore improve forecast accuracy. We use panel data collected in Tolo Harbour, Hong Kong, to validate the model. The model demonstrates good forecasting for out‐of‐sample rolling forecasts, especially for algal bloom appearing for a longer period, which severely damages fisheries and the marine environment.

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Toxic phytoplankton blooms in the southwestern Gulf of Maine: testing hypotheses of physical control using historical data

Cited by 62 publications

References 10 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

Toxic Alexandrium blooms in the western Gulf of Maine: The plume advection hypothesis revisited

A Bayesian structural model for predicting algal blooms

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