d.fossileShapes: Coccolith Abundance and Environmental Variables

In plgraphics: User Oriented Plotting Functions

Coccolith Abundance and Environmental Variables

Description

The abundance of cocolith shells can be used to infer environmental conditions in epochs corresponding to earlier epochs. This data set contains the core location, the relative abundance of Gephyrocapsa morphotypes and the sea surface temperatures from all deep see cores used in this study.

Usage

data("d.fossileShapes")
data("d.fossileSamples")

Format

d.fossilShapes: A data frame with 5864 observations on the following 15 variables:
Identification and location of the sample:

Sample

Identification number of the sample

Sname

Identification code

Magnification

(technical)

Shape features and recommended transformations:

Angle

bridge angle

Length, Width

lengtha and width of the shell

CLength, CWidth

length and width of the 'central area'

Cratio

ratio between width and length of the central area

sAngle

sqrt of Angle

lLength

log10(Length)

rWidth, rCLength, rCWidth

relative measures, percentage of Length

Cratio

CWidth/Clength

ShapeClass

shape class as defined in the cited paper, classes ar CM < CC < CT < CO < CE < CL

d.fossilSamples: A data frame with 108 observations on the following 32 variables:
Identification and location:

Sample

Identification number of the sample (as above)

Sname

Identification code

Latitude, Longitude

Coordinates of the location

Region

Ocean: Pacific, Atlantic, Indian.Ocean

SDepth

sample depth below soil surface [cm]

WDepth

Water depth [m]

N

number of specimen measured

Shape features as above, averaged. (This is the reason for introducing transformed variables above: The transformed values are averaged.)

CM, CC, CT, CO, CE, CL

percentages of shape classes in the sample

Environment:

SST

Sea Surface Temperature, mean, [deg C]

SST.Spring, SST.Summer, SST.Fall, SST.Winter

... in each season

Chlorophyll, lChlorophyll

Chlorophyll content [microgram/L] and log10 of it

Salinity

Salinity of the sea water

Details

The paradigm of research associated with this dataset is the following: Datasets of this kind are used to establish the relationship between the shell shapes of cocoliths (species Gephyrocapsa) from the most recent sediment layer with actual environmental conditions. This relationship is then used to infer environmental conditions of earlier epochs from the shell shapes from the corresponding layers.

The analysis presented in the paper cited below consisted of first introducing classes of shells based on the shapes and then use the relative abundance of the classes to predict the environmental conditions.

Source

J\"org Bollmann, Jorijntje Henderiks and Bernhard Brabec (2002). Global calibration of Gephyrocapsa coccolith abundance in Holocene sediments for paleotemperature assessment. Paleoceanography, 17(3), 1035

References

J\"org Bollmann (1997). Morphology and biogeography of Gephyrocapsa coccoliths in Holocene sediments. Marine Micropaleontology, 29, 319-350

Examples

data(d.fossileShapes)
names(d.fossileShapes)

data(d.fossileSamples)
plyx(sqrt(Angle) ~ SST, data=d.fossileSamples)

plgraphics documentation built on Oct. 15, 2025, 3:01 p.m.