Absolute nannofossil abundance estimates; quantifying the pros and cons of different techniques

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doi: 10.1016/j.revmic.2015.05.002
Author(s): Bordiga, Manuela; Bartol, Milos; Henderiks, Jorijntje
Author Affiliation(s): Primary:
Uppsala University, Department of Earth Sciences, Uppsala, Sweden
Volume Title: Revue de Micropaléontologie
Source: Revue de Micropaléontologie, 58(3), p.155-165. Publisher: Elsevier, Paris, France. ISSN: 0035-1598 CODEN: RMCPAM
Note: In English with French summary. Includes appendices. 17 refs.; illus., incl. 4 tables, 1 plate
Summary: A quick and inexpensive method to determine absolute nannofossil abundance in deep sea sediments - the "drop" technique (modified dilution method) - was compared to two other available methods - the filtration and random settling techniques. All techniques rely on the same basic principle, under which a volume of known concentration (bulk sediment weight/mL) is distributed evenly over a known total area (glass slide or filter) to then count particles within a set of (randomly) selected fields of view. The three preparation techniques were also calibrated by spiking the samples with microbeads to approach the "real values" as closely as possible. Significant offsets in abundance estimates between methods mainly reflect bias due to the uneven distribution and/or loss of particles. We show that the drop technique is most consistent and accurate in estimating "real values" and offers similar or better reproducibility than the other techniques. The drop method also allows detection of the same trends with or without calibration with microbeads. The filtration method holds the risk to drastically underestimate absolute abundances, while the settling technique is demanding in terms of time and may suffer from advection processes. The composition of nannofossil assemblages can be reliably determined by any of the three different techniques. Abstract Copyright (2015) Elsevier, B.V.
Year of Publication: 2015
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 09 Paleontology, Paleobotany; Algae; Atlantic Ocean; Ceara Rise; Concentration; DSDP Site 608; Deep Sea Drilling Project; Deep-sea environment; Dilution; Equatorial Atlantic; Filtration; IPOD; Leg 154; Leg 208; Leg 94; Marine environment; Methods; Microfossils; Nannofossils; North Atlantic; Northeast Atlantic; ODP Site 1263; ODP Site 929; Ocean Drilling Program; Plantae; Quantitative analysis; Sample preparation; South Atlantic; Statistical analysis; Techniques; Walvis Ridge
Coordinates: N425012 N425013 W0230515 W0230515
N055834 N055834 W0434423 W0434423
S283200 S283200 E0024700 E0024700
Record ID: 2019054658
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands