How to react to shallow water hydrodynamics: The larger benthic foraminifera solution

Author(s)

Johann Hohenegger, Antonino Briguglio

Abstract

Symbiont-bearing larger benthic foraminifera inhabit the photic zone to provide their endosymbiotic algae

with light. Because of the hydrodynamic conditions of shallow water environments, tests of larger foraminifera

can be entrained and transported by water motion. To resist water motion, these foraminifera have to build a

test able to avoid transport or have to develop special mechanisms to attach themselves to substrate or to hide

their test below sediment grains. For those species which resist transport by the construction of hydrodynamic

convenient shapes, the calculation of hydrodynamic parameters of their test defines the energetic input they

can resist and therefore the scenario where they can live in. Measuring the density, size and shape of every test,

combined with experimental data, helps to define the best mathematical approach for the settling velocity

and Reynolds number of every shell. The comparison between water motion at the sediment-water interface

and the specimen-specific settling velocity helps to calculate the water depths at which, for a certain test type,

transport, deposition and accumulation may occur. The results obtained for the investigated taxa show that the

mathematical approach gives reliable results and can discriminate the hydrodynamic behaviour of different

shapes. Furthermore, the study of the settling velocities, calculated for all the investigated taxa, shows that

several species are capable to resist water motion and therefore they appear to be functionally adapted to the

hydrodynamic condition of its specific environment.

The same study is not recommended on species which resist water motion by adopting hiding or anchoring

strategies to avoid the effect of water motion.

Organisation(s)

Department of Palaeontology

Journal

Marine Micropaleontology

Volume

81

Pages

63-76

No. of pages

14

ISSN

0377-8398

Publication date

2011

Peer reviewed

Yes

Austrian Fields of Science 2012

105118 Palaeontology

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