scholarly journals Contribution of the deep chlorophyll maximum to primary production, phytoplankton assemblages and diversity in a small stratified lake

2020 ◽  
Author(s):  
Alexandrine Pannard ◽  
Dolors Planas ◽  
Philippe Le Noac’h ◽  
Myriam Bormans ◽  
Myriam Jourdain ◽  
...  
Keyword(s):  
Primary Production ◽  
Deep Layer ◽  
Light Attenuation ◽  
Environmental Drivers ◽  
Total Production ◽  
Deep Chlorophyll Maximum ◽  
Phytoplankton Assemblages ◽  
Stratified Lake ◽  
Stratified Lakes ◽  
Chlorophyll Maximum

Abstract This 6-month study characterized the contribution of deep chlorophyll maximum (DCM) to lake phytoplankton diversity and primary production, in relation to stratification during the ice-free season. Phytoplankton and zooplankton dynamics were examined with environmental drivers in a small stratified lake that presents vertical gradients of light and nutrients. The phytoplankton, first composed of diatoms and chrysophyceae, shifted to cyanobacteria in mid-July. With stratification increase, surface nutrient limitation appeared to favor motile species characteristic of oligotrophic environments above a deep layer of filamentous cyanobacteria, fueled by the vertical nutrient fluxes from sediment. The DCM contributed on average to 33% (but up to 60%) of total production during the strongest summer stratification period. In late summer, as stratification was eroding, the vertical gradient of nutrients was reduced, but light attenuation with depth increased. Distinct assemblages were identified between surface and deep layer with shade-adapted species. The contribution of DCM was reduced to 10%. Zooplankton community varied in conjunction with phytoplankton and stratification. Our study demonstrates no benefit of DCM for taxonomic and functional diversity and a limited contribution to total production. The depths over which phytoplankton use separate spatial niches may be lesser in a 6-m-deep lake compared with deeper stratified lakes.

The contribution of the deep chlorophyll maximum to primary production in a seasonally stratified shelf sea, the North Sea

2013 ◽  
Vol 113 (1-3) ◽  
pp. 153-166 ◽  
Author(s):  
Liam Fernand ◽  
Keith Weston ◽  
Tom Morris ◽  
Naomi Greenwood ◽  
Juan Brown ◽  
...  
Keyword(s):  
Primary Production ◽  
North Sea ◽  
Deep Chlorophyll Maximum ◽  
Chlorophyll Maximum ◽  
The North ◽  
Shelf Sea ◽  
The North Sea

scholarly journals Primary production in the deep chlorophyll maximum of the central North Sea

2005 ◽  
Vol 27 (9) ◽  
pp. 909-922 ◽  
Author(s):  
K. Weston ◽  
L. Fernand ◽  
D. K. Mills ◽  
R. Delahunty ◽  
J. Brown
Keyword(s):  
Primary Production ◽  
North Sea ◽  
Deep Chlorophyll Maximum ◽  
Chlorophyll Maximum ◽  
Central North Sea

scholarly journals Primary production in the deep chlorophyll maximum of the central North Sea

2011 ◽  
Vol 33 (10) ◽  
pp. 1627-1628 ◽  
Author(s):  
K. Weston ◽  
L. Fernand ◽  
D. K. Mills ◽  
R. Delahunty ◽  
J. Brown
Keyword(s):  
Primary Production ◽  
North Sea ◽  
Deep Chlorophyll Maximum ◽  
Chlorophyll Maximum ◽  
Central North Sea

scholarly journals Analytical solution of nitracline with the evolution of subsurface chlorophyll maximum in stratified water columns

2016 ◽  
Author(s):  
Xiang Gong ◽  
Wensheng Jiang ◽  
Linhui Wang ◽  
Huiwang Gao ◽  
Emmanuel Boss ◽  
...  
Keyword(s):  
Light Intensity ◽  
Analytical Solution ◽  
Primary Production ◽  
Attenuation Coefficient ◽  
Light Attenuation ◽  
Euphotic Zone ◽  
Light Level ◽  
Chlorophyll Maximum ◽  
Subsurface Chlorophyll Maximum ◽  
Light Attenuation Coefficient

Abstract. In a stratified water column, the nitracline is a layer where the nitrate concentration increases below the nutrient-depleted upper layer, exhibiting a strong vertical gradient in the euphotic zone. The subsurface chlorophyll maximum layer (SCML) forms near the bottom of euphotic zone, acting as a trap to diminish the upward nutrient supply. Depth and steepness of the nitracline are important measurable parameters related to the vertical transport of nitrate into the euphotic zone. The correlation between the SCML and the nitracline has been widely reported in the literature, but the analytic solution for the relationship between them is not well established. By incorporating a piecewise function for the approximate Gaussian vertical profile of chlorophyll, we derive analytical solutions for the system of phytoplankton and nutrient. The analytical solution shows that the nitracline depth is deeper than the depth of SCML, shoaling with an increase in light attenuation coefficient and with a decrease in surface light intensity. The inverse proportional relationship between the light level at the nitracline depth and the maximum rate of new primary production is derived, suggesting that the light level at the nitracline can be used as an indicator for integrated new primary production. Analytic solutions also show that a thinner SCML corresponds to a steeper nitracline. The nitracline steepness is positively related to light attenuation coefficient, but independent of surface light intensity. The derived equations of the nitracline in relation to the SCML provide further insight into the important role of the nitracline in marine pelagic ecosystems.

Macrozooplankton and the persistence of the deep chlorophyll maximum in a stratified lake

2015 ◽  
Vol 60 (8) ◽  
pp. 1717-1733 ◽  
Author(s):  
Alexandrine Pannard ◽  
Dolors Planas ◽  
Beatrix E. Beisner
Keyword(s):  
Deep Chlorophyll Maximum ◽  
Stratified Lake ◽  
Chlorophyll Maximum

scholarly journals Environmental drivers of spring primary production in Hudson Bay

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
L. C. Matthes ◽  
J. K. Ehn ◽  
L. A. Dalman ◽  
D. G. Babb ◽  
I. Peeken ◽  
...  
Keyword(s):  
Sea Ice ◽  
Primary Production ◽  
Inorganic Nitrogen ◽  
Late Spring ◽  
Environmental Drivers ◽  
Phytoplankton Production ◽  
Hudson Bay ◽  
Total Production ◽  
Mean Values ◽  
Light Levels

Pertinent environmental factors influencing the microalgal bloom during sea-ice breakup in Hudson Bay were investigated in June 2018, producing the first observations of late spring primary production in the offshore waters of this vast inland sea. Phytoplankton production was found to commence at the onset of ice melt, with surface nutrient depletion leading to the formation of a subsurface chlorophyll maximum in the open waters of western Hudson Bay. Concurrently, the melting mobile ice cover in central Hudson Bay created favorable conditions for a diatom-dominated under-ice bloom, with photosynthetic characteristics and relatively high production confirming that phytoplankton cells were able to acclimate to increasing light levels. Lower mean values of phytoplankton production and total chlorophyll a (TChl a) concentration observed under the sea ice (414 mg C m–2 d–1 and 33.7 mg TChl a m–2) than those observed in open waters during the late bloom stage in the western region (460 mg C m–2 d–1 and 53.5 mg TChl a m–2) were attributed to reduced under-ice light levels and low surface concentrations of dissolved inorganic nitrogen (<2 μmol L–1) in central Hudson Bay. However, the highly abundant subice diatom, Melosira arctica, was estimated to contribute an additional 378 mg C m–2 d–1 to under-ice production in this region. Therefore, this subice algal bloom appears to play a similar role in the seasonally ice-covered sub-Arctic as in the central Arctic Ocean where it contributes significantly to local production. By updating historical total production estimates of Hudson Bay ranging between 21.5 and 39 g C m–2 yr–1 with our late spring observations including the novel observation of M. arctica, annual production was recalculated to be 72 g C m–2 yr–1, which equates to mean values for interior Arctic shelves.

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