Reflections About Chance in My Career, and on the Top-Down Regulated World

Banse, Karl

doi:10.1146/annurev-marine-121211-172359

Cited by 59 publications

(47 citation statements)

References 68 publications

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“…It is thus valid to ask whether the extremes of plasticity observable in mono-cultures, including high quotas under conditions of high excess trace metal (bio-)availability and in particular the low quotas associated with severe nutrient limitation, might be expected to be fully expressed at the level of mixed communities within the natural system [121]. Net growth rates of organisms within natural communities will be a function of both bottom-up and top-down controls [122] such that microbes under severe growth rate nutrient limitation are likely to be rapidly outcompeted [121]. Thus, it might be hypothesized that the majority of new biomass would actually be produced by cells which are not severely nutrient limited and which hence have nutrient quotas towards the higher end of observed ranges (figure 1).…”

Section: (D) Deficiency Beyond N P and Fe: Mn And Znmentioning

confidence: 99%

Diagnosing oceanic nutrient deficiency

Moore¹

2016

Phil. Trans. R. Soc. A.

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Section: (D) Deficiency Beyond N P and Fe: Mn And Znmentioning

confidence: 99%

Diagnosing oceanic nutrient deficiency

Moore¹

2016

Phil. Trans. R. Soc. A.

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“…Whether or not phytoplankton populations are controlled primarily by nutrient limitation or by grazing or viral lysis is debated (e.g. Banse, 2013 and references cited therein). Meanwhile, the global core-top calibration for the temperature proxy is statistically identical to that observed during the exponential phase of an E. huxleyi culture (Müller et al, 1998) but a resemblance in the alkenone and alkenoate composition of surface sediments to those of nutrient stressed haptophyte cells has also been observed (Conte et al, 1998;Prahl et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

The effects of growth phase and salinity on the hydrogen isotopic composition of alkenones produced by coastal haptophyte algae

Chivall

M'Boule

Sinke-Schoen

et al. 2014

Geochimica et Cosmochimica Acta

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The isotopic fractionation of hydrogen during the biosynthesis of alkenones produced by marine haptophyte algae has been shown to depend on salinity and, as such, the hydrogen isotopic composition of alkenones is emerging as a palaeosalinity proxy. The relationship between fractionation and salinity has previously only been determined during exponential growth, whilst it is not yet known in which growth phases natural haptophyte populations predominantly exist. We have therefore determined the relationship between the fractionation factor, α alkenones-water , and salinity for C 37 alkenones produced in different growth phases of batch cultures of the major alkenone-producing coastal haptophytes Isochrysis galbana (strain CCMP 1323) and Chrysotila lamellosa (strain CCMP 1307) over a range in salinity from ca. 10 to 35. α alkenones-water was similar in both species, ranging over 0.841-0.900 for I. galbana and 0.838-0.865 for C. lamellosa. A strong (0.85 ≤ R 2 ≤ 0.97; p < 0.0001) relationship between salinity and fractionation factor was observed in both species at all growth phases investigated. This suggests that alkenone δD has the potential to be used as a salinity proxy in neritic areas where haptophyte communities are dominated by these coastal species. However, there was a marked difference in the sensitivity of α alkenones-water to salinity between different growth phases: in the exponential growth phase of I. galbana, α alkenones-water increased by 0.0019 per salinity unit (S -1 ), but was less sensitive at 0.0010 S -1 and 0.0008 S -1 during the stationary and decline phases, respectively. Similarly, in C. lamellosa α alkenones-water increased by 0.0010 S -1 in the early stationary phase and by 0.0008 S -1 during the late stationary phase. Assuming the shift in sensitivity of α alkenones-water to salinity observed at the end of exponential growth in I. galbana is similar in other alkenone-producing species, the predominant growth phase of natural populations of haptophytes will affect the sensitivity of the alkenone salinity proxy. The proxy is likely to be most sensitive to salinity when alkenones are produced in a state similar to exponential growth. IntroductionOne of the important controls of climate in the late Quaternary is ocean circulation (e.g. Broecker et al., 1985), which transports heat and moisture around the globe (Ganachaud and Wunsch, 2000). This circulation depends on, amongst other factors, differences in seawater density, which in turn are partly dependent on salinity. Meanwhile, 86% of evaporation and 78% of precipitation occur over the ocean (Baumgartner and Reichel, 1975), the relative amounts of which affect salinity at the sea surface (e.g. Durack et al., 2012). Therefore, the ability to reconstruct past sea surface salinities is of importance to understand past changes in both ocean dynamics and the hydrological cycle.Currently, the hydrogen isotopic composition (δD) of C 37 alkenones is emerging as a potential sea surface salinity proxy. These long-chain alkenones are acet...

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“…Phytoplankton provides almost all of the primary production in the upper ocean. Microzooplankton (< 200 µm) consumes most of the daily primary production in the sea, and regulates phytoplankton community composition, and affects the ultimate fate of the phytoplankton-derived primary production (Banse, 2007(Banse, , 2013Landry and Calbet, 2004;Schmoker et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Seasonal and size-dependent variations in the phytoplankton growth and microzooplankton grazing in the southern South China Sea under the influence of the East Asian monsoon

et al. 2015

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Abstract.To examine seasonal and size-dependent variations in the phytoplankton growth and microzooplankton grazing in oligotrophic tropical waters under the influence of seasonal reversing monsoon, dilution experiments were conducted during the summer of 2009 (21 May to 9 June) and winter 2010 (9 to 18 November) in the southern South China Sea (SSCS). The results showed that environmental variables, phytoplankton biomass, phytoplankton growth rate (µ), microzooplankton grazing rate (m), and correlationship (coupling) between the µ and m, rather than the microzooplankton grazing impact on phytoplankton (m/µ) significantly varied between the two seasons. Higher relative preference index (RPI) for the larger-sized (> 3 µm) phytoplankton than pico-phytoplankton (< 3 µm), indicating significant size-selective grazing by microzooplankton on the larger-sized phytoplankton, were also observed. The µ and m were significantly correlated with seawater salinity and temperature, and phytoplankton biomass, which indicated that salient seasonal variations in the phytoplankton growth and microzooplankton grazing in the SSCS were closely related to the environmental variables under the influence of the East Asian monsoon. We propose that intermittent arrivals of the northeast winter monsoon could lead to the low µ and m, and the decoupling between the µ and m in the SSCS, through influencing nutrient supply to the surface water, and inducing surface seawater salinity decrease. The low m/µ (< 50 % on average) indicates low remineralization of organic matter mediated by microzooplankton and mismatch between the µ and m, and thus probably accounts for part of the high vertical biogenic particle fluxes in the prevailing periods of the monsoons in the SSCS. The size-selective grazing suggests that microzooplankton grazing partially contributes to the pico-phytoplankton dominance in the oligotrophic tropical waters such as that of the SSCS.

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Reflections About Chance in My Career, and on the Top-Down Regulated World

Cited by 59 publications

References 68 publications

Diagnosing oceanic nutrient deficiency

Diagnosing oceanic nutrient deficiency

The effects of growth phase and salinity on the hydrogen isotopic composition of alkenones produced by coastal haptophyte algae

Seasonal and size-dependent variations in the phytoplankton growth and microzooplankton grazing in the southern South China Sea under the influence of the East Asian monsoon

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