ISSN:
1573-5117
Keywords:
eastern equatorial Pacific
;
productivity
;
Quaternary
;
diatoms
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Recent marine planktonic diatom assemblages from 47 sediment surface samples retrieved from the eastern equatorial Pacific yielded four significant Q-mode factors that are related to surface water properties. They include a northern subtropical (Factor 1), a southern subtropical (Factor 2), a Peru Current (Factor 3) and an eastern Equatorial Pacific (Factor 4) factor. A transfer function (based on 42 surface sediment samples) with a productivity range of 109 to 210 gC m−2 y−1 was defined using the geographic distribution of the northern and southern subtropical assemblages (Factor 1 and 2) and their relation to ”mapped“ surface water primary productivity. This transfer function has a standard error of estimate of 11.9 gC m−2 y−1 and it is used to estimate late Pleistocene paleo-productivity changes at ODP Leg 111 Site 677 off Ecuador. The Site 677 samples (usually spaced 10 cm apart and with a linear sedimentation rate of 4.3 cm y−3) were the same samples that were used for stable oxygen/carbon isotopic analysis from planktonic Foraminifera. The well constrained oxygen isotope stratigraphy permitted assignment of accurate ages to downcore samples. The interval between oxygen isotope stages 3 and 9 had variable productivity that is generally higher than present values of 175 gC m−2 y−1 A major decline in paleo-productivity below the present value occurred in stage 9, the early part of stage 8 and in the early and late stage 5.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00028013
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