The Advent of the Spring Bloom in the Eastern Subarctic Pacific Ocean

1966 ◽  
Vol 23 (4) ◽  
pp. 539-546 ◽  
Author(s):  
T. R. Parsons ◽  
L. F. Giovando ◽  
R. J. LeBrasseur
Keyword(s):  
Pacific Ocean ◽  
Primary Production ◽  
Mixed Layer ◽  
Spring Bloom ◽  
Phytoplankton Bloom ◽  
Central Area ◽  
Critical Depth ◽  
Spring Phytoplankton Bloom ◽  
Subarctic Pacific ◽  
Subarctic Pacific Ocean

The spring phytoplankton bloom in the eastern subarctic Pacific Ocean was described from estimations of the critical depth and the depth of the mixed layer. The results suggested that the spring bloom begins during February in the area south of 45°N and east of 135°W. During March the bloom area advances in a northwesterly direction to 50°N at 125°W and 45°N at 135°W. A net increase in primary production is also possible during March near 55°N and 155°W. During April, the spring bloom is generally well established throughout the region except in a central area where suitable conditions are not firmly established until May. This description is supported by the distribution of copepods in the region during April.

scholarly journals A newly observed physical cause of the onset of the subsurface spring phytoplankton bloom in the southwestern East Sea/Sea of Japan

2014 ◽  
Vol 11 (5) ◽  
pp. 1319-1329 ◽  
Author(s):  
Y.-T. Son ◽  
K.-I. Chang ◽  
S.-T. Yoon ◽  
T. Rho ◽  
J. H. Kwak ◽  
...  
Keyword(s):  
Sea Of Japan ◽  
Mixed Layer ◽  
Spring Bloom ◽  
Phytoplankton Bloom ◽  
Mixed Layer Depth ◽  
East Sea ◽  
Ulleung Basin ◽  
Intermediate Water ◽  
Spring Phytoplankton Bloom ◽  
Bloom Period

Abstract. An ocean buoy, UBIM (Ulleung Basin Integrated Mooring), deployed during the spring transition from February to May 2010 reveals for the first time highly resolved temporal variation of biochemical properties of the upper layer of the Ulleung Basin in the southwestern East Sea/Sea of Japan. The time-series measurement captured the onset of subsurface spring bloom at 30 m, and collocated temperature and current data gives an insight into a mechanism that triggers the onset of the spring bloom not documented so far. Low-frequency modulation of the mixed layer depth ranging from 10 m to 53 m during the entire mooring period is mainly determined by shoaling and deepening of isothermal depths depending on the placement of UBIM on the cold or warm side of the frontal jet. The occurrence of the spring bloom at 30 m is concomitant with the appearance of colder East Sea Intermediate Water at buoy UBIM, which results in subsurface cooling and shoaling of isotherms to the shallower depth levels during the bloom period than those that occurred during the pre-bloom period. Isolines of temperature-based NO3 are also shown to be uplifted during the bloom period. It is suggested that the springtime spreading of the East Sea Intermediate Water is one of the important factors that triggers the subsurface spring bloom below the mixed layer.

Primary production in the subarctic Pacific Ocean: Project SUPER

1993 ◽  
Vol 32 (1-4) ◽  
pp. 101-135 ◽  
Author(s):  
Nicholas A. Welschmeyer ◽  
Suzanne Strom ◽  
Ralf Goericke ◽  
Giacomo DiTullio ◽  
Marcia Belvin ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Primary Production ◽  
Subarctic Pacific ◽  
Subarctic Pacific Ocean

scholarly journals Characterizing upper-ocean mixing and its effect on the spring phytoplankton bloom with in situ data

2015 ◽  
Vol 72 (6) ◽  
pp. 1961-1970 ◽  
Author(s):  
Sarah R. Brody ◽  
M. Susan Lozier
Keyword(s):  
Mixed Layer ◽  
Spring Bloom ◽  
Phytoplankton Bloom ◽  
Upper Ocean ◽  
Late Winter ◽  
Uniform Density ◽  
Spring Phytoplankton Bloom ◽  
In Situ Data ◽  
Active Mixing

Abstract Since publication, the Sverdrup hypothesis, that phytoplankton are uniformly distributed within the ocean mixed layer and bloom once the ocean warms and stratifies in spring, has been the conventional explanation of subpolar phytoplankton spring bloom initiation. Recent studies have sought to differentiate between the actively mixing section of the upper ocean and the uniform-density mixed layer, arguing, as Sverdrup implied, that decreases in active mixing drive the spring bloom. In this study, we use in situ data to investigate the characteristics and depth of active mixing in both buoyancy- and wind-driven regimes and explore the idea that the shift from buoyancy-driven to wind-driven mixing in the late winter or early spring creates the conditions necessary for blooms to begin. We identify the bloom initiation based on net rates of biomass accumulation and relate changes in the depth of active mixing to changes in biomass depth profiles. These analyses support the idea that decreases in the depth of active mixing, a result of the transition from buoyancy-driven to wind-driven mixing, control the timing of the spring bloom.

Seasonal Variation of the Chlorophyll a:Pheopigment Ratio in the Gulf of St. Lawrence

1974 ◽  
Vol 31 (7) ◽  
pp. 1263-1268 ◽  
Author(s):  
C. Spence ◽  
D. M. Steven
Keyword(s):  
Seasonal Variation ◽  
Primary Production ◽  
Chlorophyll A ◽  
Annual Cycle ◽  
Spring Bloom ◽  
Phytoplankton Bloom ◽  
Zooplankton Biomass ◽  
Spring Phytoplankton Bloom ◽  
Rate Of Growth ◽  
Close Relationship

Measurements of the chlorophyll a:pheopigment ratio from all parts of the Gulf of St. Lawrence showed a close relationship between changes in the ratio and the annual cycle of primary production. The chlorophyll a fraction was greatest at the time of the spring phytoplankton bloom and was lowest during the winter. Differences in the timing of the spring bloom from year to year and between regions of the Gulf indicated that changes in the chlorophyll a:pheopigment ratio were determined primarily by the rate of growth of phytoplankton and were due mainly to variation in the amount of chlorophyll a. No relationship was found between the amount of pheopigment and zooplankton biomass.

scholarly journals Iron stable isotopes track pelagic iron cycling during a subtropical phytoplankton bloom

2014 ◽  
Vol 112 (1) ◽  
pp. E15-E20 ◽  
Author(s):  
Michael J. Ellwood ◽  
David A. Hutchins ◽  
Maeve C. Lohan ◽  
Angela Milne ◽  
Philipp Nasemann ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Mixed Layer ◽  
Phytoplankton Bloom ◽  
Iron Bioavailability ◽  
Global Ocean ◽  
Minor Role ◽  
Surface Mixed Layer ◽  
Spring Phytoplankton Bloom ◽  
Dissolved Iron ◽  
Particulate Iron

The supply and bioavailability of dissolved iron sets the magnitude of surface productivity for ∼40% of the global ocean. The redox state, organic complexation, and phase (dissolved versus particulate) of iron are key determinants of iron bioavailability in the marine realm, although the mechanisms facilitating exchange between iron species (inorganic and organic) and phases are poorly constrained. Here we use the isotope fingerprint of dissolved and particulate iron to reveal distinct isotopic signatures for biological uptake of iron during a GEOTRACES process study focused on a temperate spring phytoplankton bloom in subtropical waters. At the onset of the bloom, dissolved iron within the mixed layer was isotopically light relative to particulate iron. The isotopically light dissolved iron pool likely results from the reduction of particulate iron via photochemical and (to a lesser extent) biologically mediated reduction processes. As the bloom develops, dissolved iron within the surface mixed layer becomes isotopically heavy, reflecting the dominance of biological processing of iron as it is removed from solution, while scavenging appears to play a minor role. As stable isotopes have shown for major elements like nitrogen, iron isotopes offer a new window into our understanding of the biogeochemical cycling of iron, thereby allowing us to disentangle a suite of concurrent biotic and abiotic transformations of this key biolimiting element.

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