Vertical and horizontal distribution of coccolithophores in the Caribbean Sea

Winter, Amos; Rost, Björn; Hilbrecht, Heinz; Elbrächter, Malte

doi:10.1007/s00367-002-0108-8

Cited by 21 publications

(5 citation statements)

References 39 publications

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“…Table 1) are shown for comparison in panel (c). The drop in lith size from the Pliocene to Pleistocene is similar to what has been documented previously (Young, 1990). Outliers in panels (a) and (d) were calculated following the 1.5 rule in R (R Core Team, 2015).…”

Section: Resultssupporting

confidence: 75%

“…An alternative explanation however could be that the parameterization of physiological factors into the b term model is simply flawed in general, or is at least lacking important components. The dominant species producing alkenones in this part of the Caribbean today is Emiliania huxleyi (Winter et al, 2002). E. huxleyi first appeared 290 kyr ago but did not become the dominant Noelaerhabdaceae until ∼ 82 ka, when it began to outcompete the closely related Gephyrocapsa spp., which in turn took over from Reticulofenestra in the late Pliocene (Raffi et al, 2006;Gradstein et al, 2012).…”

Section: Resultsmentioning

confidence: 99%

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Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels

et al. 2019

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Abstract. Atmospheric pCO2 is a critical component of the global carbon system and is considered to be the major control of Earth's past, present, and future climate. Accurate and precise reconstructions of its concentration through geological time are therefore crucial to our understanding of the Earth system. Ice core records document pCO2 for the past 800 kyr, but at no point during this interval were CO2 levels higher than today. Interpretation of older pCO2 has been hampered by discrepancies during some time intervals between two of the main ocean-based proxy methods used to reconstruct pCO2: the carbon isotope fractionation that occurs during photosynthesis as recorded by haptophyte biomarkers (alkenones) and the boron isotope composition (δ11B) of foraminifer shells. Here, we present alkenone and δ11B-based pCO2 reconstructions generated from the same samples from the Pliocene and across a Pleistocene glacial–interglacial cycle at Ocean Drilling Program (ODP) Site 999. We find a muted response to pCO2 in the alkenone record compared to contemporaneous ice core and δ11B records, suggesting caution in the interpretation of alkenone-based records at low pCO2 levels. This is possibly caused by the physiology of CO2 uptake in the haptophytes. Our new understanding resolves some of the inconsistencies between the proxies and highlights that caution may be required when interpreting alkenone-based reconstructions of pCO2.

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Section: Resultssupporting

confidence: 75%

Section: Resultsmentioning

confidence: 99%

Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels

et al. 2019

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“…An alternative explanation however could be that the invariant parameterisation of physiological factors into the 'b' termmodel could be flawed or at least lacking important components. The dominant species producing alkenones in this part of the Caribbean today, and likely since its first appearance 290 kyrs ago, is Emiliania huxleyi (Winter et al, 2002). Recent experimental work has shown that this globally important species has evolved a carbon concentrating mechanism (CCM) to respond to limiting CO2 by upregulating genes at low DIC to maintain carbon requirements (Bach et al, 2013).…”

Section: Resultsmentioning

confidence: 99%

Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels

Badger¹,

Chalk²,

Foster³

et al. 2018

Preprint

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Abstract. Atmospheric pCO2 is a critical component of the global carbon system and is considered to be the major control of Earth's past, present and future climate. Accurate and precise reconstructions of its concentration through geological time are, therefore, crucial to our understanding of the Earth system. Ice core records document pCO2 for the past 800 kyrs, but at no point during this interval were CO2 levels higher than today. Interpretation of older pCO2 has been hampered by discrepancies during some time intervals between two of the main ocean-based proxy methods used to reconstruct pCO2: the carbon isotope fractionation that occurs during photosynthesis as recorded by haptophyte biomarkers (alkenones) and the boron isotope composition (δ11B) of foraminifer shells. Here we present alkenone and δ11B-based pCO2 reconstructions generated from the same samples from the Plio-Pleistocene at ODP Site 999 across a glacial-interglacial cycle. We find a muted response to pCO2 in the alkenone record compared to contemporaneous ice core and δ11B records, suggesting caution in the interpretation of alkenone-based records at low pCO2 levels. This is possibly caused by the physiology of CO2 uptake in the haptophytes. Our new understanding resolves some of the inconsistencies between the proxies and highlights that caution may be required when interpreting alkenone-based reconstructions of pCO2.

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“…dynamics. For example, unlike coastal temperate waters where diatoms dominate (Rousseau et al, 2002;Barton et al, 2013), the Caribbean phytoplankton community is dominated by coccolithophores (Winter et al, 2002), phytoplankton that do not require Si to survive. While pulses of diatom blooms do occur in the Caribbean (Dandonneau et al, 2006), such blooms are often associated with La Niña events and are short-lived (Alvain et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

High Productivity Makes Mangroves Potentially Important Players in the Tropical Silicon Cycle

et al. 2021

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Over the last two decades, recognition of the important role terrestrial plants play in regulating silicon (Si) cycling has emerged. Si improves plant fitness by protecting them from abiotic (e.g., desiccation) and biotic (e.g., fungal attack) stressors. Once incorporated into plant biomass this biogenic Si is more bio-available than the lithogenic material from which it was ultimately derived. Thus plants play a key function in regulating the amount and timing of Si availability in downstream ecosystems. Recent work has highlighted the importance of salt marshes in the temperate Si cycle. However, the role of their tropical counterparts, mangroves, has largely gone unexplored. Here we report foliar concentrations of plant Si (as %Si by dry weight) for four Caribbean mangrove species: Conocarpus erectus (buttonwood), Laguncularia racemosa (white mangrove), Avicennia germinans (black mangrove), and Rhizophora mangle (red mangrove). Overall, the median Si concentration was low (0.07%) and did not vary among plant part (e.g., foliage, twig, and propagule). There was also little variation in Si among species. Using literature values of aboveground net primary production, and the concentrations reported here, we estimate an aboveground mangrove Si uptake rate of 2–10 kg Si ha–1 year–1. These rates are on par with rates reported for temperate and boreal forests as well as low nutrient salt marshes, but lower than estimates for high nutrient salt marshes. Thus, despite the low Si concentrations observed in mangroves, their high productivity appears to make them a hot spot of Si cycling in tropical coastal systems.

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Vertical and horizontal distribution of coccolithophores in the Caribbean Sea

Abstract: Coccolithophores are one of the major,

Cited by 21 publications

References 39 publications

Insensitivity of alkenone carbon isotopes to atmospheric CO<sub>2</sub> at low to moderate CO<sub>2</sub> levels

Insensitivity of alkenone carbon isotopes to atmospheric CO<sub>2</sub> at low to moderate CO<sub>2</sub> levels

Insensitivity of alkenone carbon isotopes to atmospheric CO<sub>2</sub> at low to moderate CO<sub>2</sub> levels

High Productivity Makes Mangroves Potentially Important Players in the Tropical Silicon Cycle

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Vertical and horizontal distribution of coccolithophores in the Caribbean Sea

Abstract: Coccolithophores are one of the major,

Cited by 21 publications

References 39 publications

Insensitivity of alkenone carbon isotopes to atmospheric CO&lt;sub&gt;2&lt;/sub&gt; at low to moderate CO&lt;sub&gt;2&lt;/sub&gt; levels

Insensitivity of alkenone carbon isotopes to atmospheric CO&lt;sub&gt;2&lt;/sub&gt; at low to moderate CO&lt;sub&gt;2&lt;/sub&gt; levels

Insensitivity of alkenone carbon isotopes to atmospheric CO&lt;sub&gt;2&lt;/sub&gt; at low to moderate CO&lt;sub&gt;2&lt;/sub&gt; levels

High Productivity Makes Mangroves Potentially Important Players in the Tropical Silicon Cycle

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Insensitivity of alkenone carbon isotopes to atmospheric CO<sub>2</sub> at low to moderate CO<sub>2</sub> levels

Insensitivity of alkenone carbon isotopes to atmospheric CO<sub>2</sub> at low to moderate CO<sub>2</sub> levels

Insensitivity of alkenone carbon isotopes to atmospheric CO<sub>2</sub> at low to moderate CO<sub>2</sub> levels