The influence of changes in nitrogen: silicon ratios on diatom growth dynamics

Gilpin, Linda; Davidson, Keith; Roberts, Edward

doi:10.1016/j.seares.2003.05.005

Cited by 114 publications

(59 citation statements)

References 45 publications

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“…Nutrient limitation of larger cells, which dominated productivity in the present study, may have been a contributory factor. For example, the average N : Si ratio for the duration of P 1 (4.49 ± 0.78) indicated potential silicate limitation of diatom growth (Brzezinski, 1985;Gilpin et al, 2004). However, relatively high-nutrient concentrations were detected by T 7 and a shift in community structure was not observed; the comparable decrease in cell abundance across all phytoplankton classes implied a less specific driver behind the decrease in biomass during the relatively short duration of this investigation.…”

Section: R Clark Et Al: the Significance Of Nitrogen Regeneratiomentioning

confidence: 66%

The significance of nitrogen regeneration for new production within a filament of the Mauritanian upwelling system

2016

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Abstract. The Lagrangian progression of a biological community was followed in a filament of the Mauritanian upwelling system, north-west Africa, during offshore advection. The inert dual tracers sulfur hexafluoride and helium-3 labelled a freshly upwelled patch of water that was mapped for 8 days. Changes in biological, physical, and chemical characteristics were measured, including phytoplankton productivity, nitrogen assimilation, and regeneration. Freshly upwelled water contained high nutrient concentrations but was depleted in N compared to Redfield stoichiometry. The highest rate of primary productivity was measured on the continental shelf, associated with high rates of nitrogen assimilation and a phytoplankton community dominated by diatoms and flagellates. Indicators of phytoplankton abundance and activity decreased as the labelled water mass transited the continental shelf slope into deeper water, possibly linked to the mixed layer depth exceeding the light penetration depth. By the end of the study, the primary productivity rate decreased and was associated with lower rates of nitrogen assimilation and lower nutrient concentrations. Nitrogen regeneration and assimilation took place simultaneously. Results highlighted the importance of regenerated NH + 4 in sustaining phytoplankton productivity and indicate that the upwelled NO − 3 pool contained an increasing fraction of regenerated NO − 3 as it advected offshore. By calculating this fraction and incorporating it into an f ratio formulation, we estimated that of the 12.38 Tg C of annual regional production, 4.73 Tg C was exportable.

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Section: R Clark Et Al: the Significance Of Nitrogen Regeneratiomentioning

confidence: 66%

The significance of nitrogen regeneration for new production within a filament of the Mauritanian upwelling system

2016

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“…10h). For diatoms, nitrogen:silica ratios of 4:1 have been shown to be an indication of silica limitation, not nitrogen limitation (Gilpin et al 2004).…”

Section: Pc3mentioning

confidence: 99%

Temporal changes in plankton of the North Sea: community shifts and environmental drivers

Álvarez-Fernández¹,

Lindeboom²,

Meesters³

2012

Mar. Ecol. Prog. Ser.

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This paper analyses long-term and seasonal changes in the North Sea plankton community during the period 1970 to 2008. Based on Continuous Plankton Recorder (CPR) data covering 38 yr, major changes in both phytoplankton and zooplankton abundance and community structure were identified. Regime changes were detected around 1978, 1989 and 1998. The first 2 changes have been discussed in the literature and are defined as a cold episodic event (1978) and a regime shift towards a warm dynamic regime (1989). The effect of these 2 regime changes on plankton indicators was assessed and checked against previous studies. The 1998 change represents a shift in the abundance and seasonal patterns of dinoflagellates and the dominant zooplankton group, the neritic copepods. Furthermore, environmental factors such as air temperature, wind speed and the North Atlantic water inflow were identified as potential drivers of change in seasonal patterns, and the most-likely environmental causes for detected changes were assessed. We suggest that a change in the balance of dissolved nutrients driven by these environmental factors was the cause of the latest change in plankton community structure, which in turn could have affected the North Sea fish community. KEY WORDS: Seasonal patterns · Regime shift · North Sea · Dinoflagellates · Zooplankton · Nutrients Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 462: [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] 2012 ulation, a very abundant dinoflagellate which may have lost its niche as a result of the late development of the spring bloom.A second overall change in North Sea plankton occurred during the 1980s (Reid et al. 2001a, Beaugrand & Ibanez 2004, Alheit et al. 2005, Weijerman et al. 2005, McQuatters-Gollop et al. 2007. During this period there was a strong biogeographic shift of warm-water copepod species (associated with a decrease in cold-water species), as well as of warmwater fish species, in the northeast Atlantic (Beaugrand & Reid 2003). This indicated a change in the pelagic ecosystem of the northeast Atlantic towards a warmer dynamic regime, which seems to have been driven by climatic variables.In contrast with the late 1970s cold episodic event, the North Sea entered a warm-biological dynamic regime after the North Sea warm episodic event from 1988 to 1992 (Edwards et al. 2002). This regime can be characterised by (1) higher Phytoplankton Colour Index (PCI) values in the central North Sea, particularly during winter and summer; (2) an extended phytoplankton season; and (3) a change in the zooplankton community structure (Reid et al. 2001a). All these changes have been related to different environmental factors, such as the increase in SST and changing Atlantic water inflow through the northern North Sea (Reid et al. 2003).SST increase has also been related to changes in the meroplankton of the North Sea, particularly Echinocardium cordatum, decapod crustaceans, and bivalve larvae (Kirby et...

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“…Although variation exists, many marine diatoms have a N/Si ratio of about 1 within their biomass (Brzezinski, 1985;Levasseur and Therriault, 1987;Gilpin et al, 2004). If this ratio is applicable to the Ría de Ares-Betanzos, the N/Si molar ratio of the NEP in the inner ría, 0.9±0.2, would indicate that diatoms were particularly dominant.…”

Section: Nutrient Fertilization and Net Utilization Patternsmentioning

confidence: 99%

Net ecosystem metabolism of a coastal embayment fertilised by upwelling and continental runoff

Villegas‐Ríos

Álvarez‐Salgado

Piedracoba

et al. 2011

Continental Shelf Research

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O 2 , N, P and Si net ecosystem metabolism of the Ría de Ares-Betanzos (NW Iberian upwelling system) was estimated during two 3-wk periods of contrasting summer downwelling and autumn upwelling conditions by means of a transient 2-D kinematic box model. The subtidal circulation was positive in both situations, although it was depressed during downwelling and enhanced during upwelling. Concurrently, the ría was fertilised mainly by shelf bottom waters, which introduced from 69% (under downwelling) to almost 100% (under upwelling) of the limiting N nutrients. The ría was an efficient nutrient trap: about 70% of the N nutrients that entered the embayment were retained under downwelling conditions (average flushing time, 9 days) and about 50% under upwelling conditions (average flushing time 3 days). Although the trapping efficiency was lower, the net ecosystem production (NEP) was much higher under upwelling (from 1.0 ± 0.3 to 1.5 ± 0.4 g C m -2 d -1 ), than under downwelling favourable winds (from 0.2 ± 0.1 to 0.3 ± 0.1 g C m -2 ). The stoichiometry of NEP suggests that P and N compounds recycled faster than C compounds, specially in the inner segment of the ría. The net degree of silification was twice in the inner than in the outer segment of the ría.

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The influence of changes in nitrogen: silicon ratios on diatom growth dynamics

Cited by 114 publications

References 45 publications

The significance of nitrogen regeneration for new production within a filament of the Mauritanian upwelling system

The significance of nitrogen regeneration for new production within a filament of the Mauritanian upwelling system

Temporal changes in plankton of the North Sea: community shifts and environmental drivers

Net ecosystem metabolism of a coastal embayment fertilised by upwelling and continental runoff

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