Regulation of growth in an estuarine clone of Gonyaulax tam arensis Lebour: Salinity-dependent temperature responses

Watras, Carl J.; Chisholm, Sallie W.; Anderson, Donald M.

doi:10.1016/0022-0981(82)90214-3

Cited by 79 publications

(69 citation statements)

References 16 publications

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“…Functional forms for the temperature and salinity dependence were fit to the data of Watras et al (1982) and Prakash (1967). Growth rate was assumed to depend linearly on ambient irradiance levels, with a simple exponential decay with depth.…”

Section: Methodsmentioning

confidence: 99%

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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Section: Methodsmentioning

confidence: 99%

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

et al. 2005

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“…Aliquots of the same nutrient-limited T. pseudonana cells were also inoculated into Aquil medium (Morel et al 1979) or were left unamended as nutrient-limited controls. Growth rates of the diatoms in the four treatments (uninfected control filtrate, filtered viral lysate, Aquil nutrients, and unamended control; each done in triplicate cultures) were monitored for several days using in vivo fluorescence, which was used as a relative index of cell density (Watras et al 1982).…”

Section: Methodsmentioning

confidence: 99%

Release and bioavailability of C, N, P Se, and Fe following viral lysis of a marine chrysophyte

Gobler

Hutchins

Fisher

et al. 1997

Limnology & Oceanography

297

231

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The potential importance of the viral lysis of phytoplankton for nutrient and carbon cycling has been acknowledged, but no quantitative assessments of this phenomenon exist. Radiotracer experiments examined the release and bioavailability of C, N, P Fe, and Se following viral lysis of the "brown tide" chrysophyte Aureococcus anophagefSeerens. Photochemical effects on the dissolved-particulate partitioning and biological uptake of virally released elements were also investigated. Viral lysis of A. anophagefSerens released 50% more C and Se than uninfected control cells to the dissolved phase, while N, P, and Fe remained in the particulate phase. There was a significant inverse correlation between A. unophugefirens and bacterial densities, as well as an increase in particulate organic nitrogen levels in cultures during viral lysis. These observations indicate thitt released dissolved organic matter supported bacterial growth and may be a pathway by which various elements are diverted in microbial food webs. Dissolved nutrients released by viral lysis were accumulated to varying degrees by natural assemblages of marine bacteria and cultured diatoms, and virally regenerated N and P relieved diatom nutrient limitation. During a 4-wk incubation, 80% of C and P within cell lysis debris was released to the diss,olved phase, likely due to bacterial activity. Photochemical degradation of cell lysis debris enhanced dissolved levels of Se (100%) and Fe (50%) and reduced total dissolved C by 15%. Photochemistry doubled the bioavailability of virally released Se to diatoms, while decreasing the bioavailability of C to bacteria threefold. The viral lysis of an A. unophugefirens bloom in the field could release 40 PM dissolved organic carbon and rapidly transfer other released elements to bacteria. Such occurrences may significantly affect water column chemistry, species composition, and succession within marine plankton communities.

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“…Temperature dependence f(T) is defined by a cubic polynomial fit to the laboratory data of Watras et al (1982) and Anderson and Keafer (unpublished …”

Section: Population Dynamics Modelmentioning

confidence: 99%

“…Salinity dependence f(S) is defined by a quadratic fit to the data of Watras et al (1982) and Prakash (1967) …”

Section: Population Dynamics 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

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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Regulation of growth in an estuarine clone of Gonyaulax tam arensis Lebour: Salinity-dependent temperature responses

Cited by 79 publications

References 16 publications

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

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

Release and bioavailability of C, N, P Se, and Fe following viral lysis of a marine chrysophyte

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

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