Identification

Title

Estimation of physiological factors controlling carbon isotope fractionation in coccolithophores in photic zone and core‐top samples

Abstract

Estimates of past pCO(2) prior to ice-core records have often been sought by measuring carbon isotopic fractionation during photosynthesis ((p)) in alkenone-producing algae present in the fossil record. Photic zone and core-top (p) show strong latitudinal gradients, which have been interpreted as an effect of growth rate. The factor b, used in previous studies to account for the changes in growth rate, shows high dependence on [CO2](aq) in culture experiments, making difficult the deconvolution of nutrients versus other effects in the field. We combine coccolithophore growth rate output from a global model, limited by sea surface temperature (SST) and [PO43-] with a statistical model that include [CO2](aq), cell size and light to predict (p), and examine the influence of different environmental and physiological variables on the observed expression of (p) in field samples. Back calculations of the growth rate necessary to match the observed (p) in photic zone and core-top samples using the statistical model show high correlation with modeled growth rates using [PO43-] and SST in temperate regions. For Southern Ocean and tropical upwelling regions, with colder and warmer SST, respectively, there might be additional factors controlling growth rate not accounted for in the model, such as grazing or nutrient recycling. We evaluate the potential to reconstruct past growth rates using planktonic foraminifera- and coccolithophore-based proxies related to water column structure. We found best application of these proxies as potential indicators of past [PO43-], which can subsequently be used in combination with proxy temperature, to estimate past coccolithophore growth rates.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7bz69bc

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2020-11-01T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact