Causes and consequences of variability in the timing of spring phytoplankton blooms

Townsend, David W.; Cammen, Leon M.; Holligan, Patrick M.; Campbell, Daniel E.; Pettigrew, Neal R.

doi:10.1016/0967-0637(94)90075-2

Cited by 198 publications

(144 citation statements)

References 52 publications

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“…In these locations, the spring bloom develops relatively early, consistent with spring in situ data from Georges Bank ) that show increasing chlorophyll concentrations and nutrient utilization as early as February or even January (Townsend and Thomas, 2002). In these regions, bathymetry restricts the depth of vertical mixing, reducing light limitation and allowing the spring bloom to begin early (Townsend et al, 1994). Along the coast of Maine, strong vertical mixing throughout the year in the EMCC brings nutrients to the surface (Townsend et al, 1987) supporting elevated chlorophyll concentrations that are advected southwest along the coast, with maximum concentrations developing offshore of the Penobscot Bay region near the terminus of the strongest flow (Figs.…”

Section: Discussionsupporting

confidence: 51%

Satellite-measured phytoplankton variability in the Gulf of Maine

Thomas

Townsend

Weatherbee

2003

Continental Shelf Research

108

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The first 4 years of SeaWiFS ocean color data (September 1997-August 2001 provide the first synoptic quantification of seasonal and interannual phytoplankton chlorophyll variability in the Gulf of Maine. Climatological monthly means show spatial patterns associated with the annual cycle. Concentrations are elevated throughout the year in coastal regions and over shallow banks (Georges Bank, Nantucket Shoals and Browns Bank) with a spring and fall bloom superimposed. Over deeper basins and the Scotia Shelf, a canonical North Atlantic seasonal cycle is present with low (o 1 mg m À3 ) winter (December-February) concentrations, an annual maximum in March-April (>2 mg m À3 ), reduced concentrations in summer and a fall bloom beginning as early as September in Jordan Basin but in OctoberNovember over other regions. Strong interannual variability over the 4-year time series shows the climatological seasonal features are often a biased picture of both timing and magnitude. The clearest interannual signal is of reduced chlorophyll concentrations throughout 1998, including weak spring and fall blooms. A connection between low concentrations in 1998 and local wind forcing is not evident. However, the low concentrations are coincident with negative anomalies in satellite surface temperature fields and follow the intrusion of relatively cold, low salinity slope water into the Northeast Channel which previous authors have argued is linked to changes in Labrador slope water transport induced by the North Atlantic Oscillation. Reduced concentrations in 1998 are consistent with both lower nitrate/nitrite concentrations in the intruding water as well as reduced subsurface stratification which would delay or reduce the onset of the spring bloom. r

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Section: Discussionsupporting

confidence: 51%

Satellite-measured phytoplankton variability in the Gulf of Maine

Thomas

Townsend

Weatherbee

2003

Continental Shelf Research

108

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“…Walsh and McRoy (1986) interpreted the presence of a sub-surface chlorophyll maximum in the middle domain as evidence of transfer of phytoplankton to the benthos, and a lack of tight coupling between primary production and copepod grazing. They hypothesized that the fate of production in the southeastern Bering Sea is influenced by water temperature, since phytoplankton growth is less sensitive to water temperature than is zooplankton growth (see also Vidal, 1980;Vidal and Smith, 1986;Townsend et al, 1994). Water temperature exerts a strong influence on the growth rates of zooplankton, and is often thought of as more important than food availability for limiting the growth rates of smallbodied copepods (McLaren, 1963;Corkett and Fig.…”

Section: Mechanisms For Change In Zooplankton Populationsmentioning

confidence: 99%

Climate change and control of the southeastern Bering Sea pelagic ecosystem

Hunt

Stabeno

Walters

et al. 2002

Deep Sea Research Part II: Topical Studies in Oceanography

498

385

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We propose a new hypothesis, the Oscillating Control Hypothesis (OCH), which predicts that pelagic ecosystem function in the southeastern Bering Sea will alternate between primarily bottom-up control in cold regimes and primarily top-down control in warm regimes. The timing of spring primary production is determined predominately by the timing of ice retreat. Late ice retreat (late March or later) leads to an early, ice-associated bloom in cold water (e.g., 1995, 1997, 1999), whereas no ice, or early ice retreat before mid-March, leads to an open-water bloom in May or June in warm water (e.g., 1996, 1998, 2000). Zooplankton populations are not closely coupled to the spring bloom, but are sensitive to water temperature. In years when the spring bloom occurs in cold water, low temperatures limit the production of zooplankton, the survival of larval/juvenile fish, and their recruitment into the populations of species of large piscivorous fish, such as walleye pollock (Theragra chalcogramma), Pacific cod (Gadus macrocephalus) and arrowtooth flounder (Atheresthes stomias). When continued over decadal scales, this will lead to bottom-up limitation and a decreased biomass of piscivorous fish. Alternatively, in periods when the bloom occurs in warm water, zooplankton populations should grow rapidly, providing plentiful prey for larval and juvenile fish. Abundant zooplankton will support strong recruitment of fish and will lead to abundant predatory fish that control forage fish, including, in the case of pollock, their own juveniles. Piscivorous marine birds and pinnipeds may achieve higher production of young and survival in cold regimes, when there is less competition from large piscivorous fish for coldwater forage fish such as capelin (Mallotus villosus). Piscivorous seabirds and pinnipeds also may be expected to have high productivity in periods of transition from cold regimes to warm regimes, when young of large predatory species of fish are numerous enough to provide forage. The OCH predicts that the ability of large predatory fish populations to sustain fishing pressure will vary between warm and cold regimes.The OCH points to the importance of the timing of ice retreat and water temperatures during the spring bloom for the productivity of zooplankton, and the degree and direction of coupling between zooplankton and forage fish. in the biomass of large piscivorous fish and a concurrent decline in the biomass of forage fish, including age-1 walleye pollock, particularly over the southern portion of the shelf. Populations of northern fur seals (Callorhinus ursinus) and seabirds such as kittiwakes (Rissa spp.) at the Pribilof Islands have declined, most probably in response to a diminished prey base. The available evidence suggests that these changes are unlikely the result of a decrease in total annual new primary production, though the possibility of reduced post-bloom production during summer remains. An ecosystem approach to management of the Bering Sea and its fisheries is of great importance if all o...

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“…Both the timing and magnitude of the bloom affect the transfer of energy to higher trophic levels (Townsend et al, 1994). The match/mismatch hypothesis between predator and prey cycles states that the survival of higher trophic levels with time-varying life stages depends on food availability at critical periods (Conover et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

Physical controls and interannual variability of the Labrador Sea spring phytoplankton bloom in distinct regions

Frajka‐Williams

Rhines

2010

Deep Sea Research Part I: Oceanographic Research Papers

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We investigated the variability of the spring phytoplankton bloom in the Labrador Sea, dividing into distinct biogeographical zones, then analyzing the relationship between the bloom and physical forcings. The spring phytoplankton bloom in the north Labrador Sea varied in intensity by a factor of 4 and in timing of onset by 3 weeks over the 11-year record from SeaWiFS satellite ocean chlorophyll, 1998-2008. This north bloom (north of 60 • N and west of the Labrador shelves) is earliest and most intense, owing in part to the offshore-directed freshwater stratification from the West Greenland Current. On interannual timescales, significant correlations were found between the north bloom intensity and ocean processes, namely offshore advection, eddy activity and runoff from Greenland. In contrast, the central Labrador Sea is later and weaker, and only a correlation between the bloom timing and irradiance was found. As the subpolar gyre shifts in strength and shape, freshwater outflow from the Arctic and Greenland changes, we may expect further changes in the biological response as indicated by these relationships.

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Causes and consequences of variability in the timing of spring phytoplankton blooms

Cited by 198 publications

References 52 publications

Satellite-measured phytoplankton variability in the Gulf of Maine

Satellite-measured phytoplankton variability in the Gulf of Maine

Climate change and control of the southeastern Bering Sea pelagic ecosystem

Physical controls and interannual variability of the Labrador Sea spring phytoplankton bloom in distinct regions

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