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Mesocosm and microcosm experiments on the feeding of temperate salt marsh Foraminifera

Jennifer L. Frail-Gauthier, Peta J. Mudie, Alastair G. B. Simpson and David B. Scott
Mesocosm and microcosm experiments on the feeding of temperate salt marsh Foraminifera
Journal of Foraminiferal Research (July 2019) 49 (3): 259-274

Abstract

Agglutinated foraminifera dominate in temperate salt marsh sediment, making them key indicators for monitoring sea level and environmental changes. Little is known about the biology of these benthic foraminifera because of difficulties in distinguishing live from dead specimens in laboratory cultures. We present data from 10 years of laboratory experiments using comparisons of the agglutinant trochamminids Trochammina inflata and Entzia macrescens and the miliolid Miliammina fusca with the calcareous rotalids Helenina anderseni and Elphidium williamsoni. Specimens were taken from a laboratory mesocosm representing Chezzetcook Inlet, a cool-temperate salt marsh in eastern Canada. We determined culture requirements for the agglutinated foraminifera in Petri dishes over 10-12 week periods. Five inexpensive, non-terminal ways of identifying live organisms were developed: spatial movement, detritus-gathering, attachment, clustering, and test opacity. Comparison with rose Bengal staining showed <10% diversion for calcareous species and T. inflata but M. fusca was over-counted by >30%. Terminal chambers of Trochammina inflata were examined by transmission electron microscopy to visualise food consumption and identify food in digestive vacuoles, both in specimens from mesocosm and in culture. Bacteria and unidentified detritus in the vacuoles establish that this agglutinated species is a saprophagous and bacterivorous detritivore. The adhesive secretions by these species apparently help them gather and possibly farm food while being relatively immobile in the sediments. Our observations of movement and feeding orientation in the agglutinants suggest links between form and function that underscore their value as ultra high resolution sea-level proxies. Mesocosm biomass and abundance counts show that foraminifera represent >50% of the meiofaunal biomass, emphasising their importance in the food web and energy-flow dynamics of temperate salt marsh systems.


ISSN: 0096-1191
EISSN: 1943-264X
Coden: JFARAH
Serial Title: Journal of Foraminiferal Research
Serial Volume: 49
Serial Issue: 3
Title: Mesocosm and microcosm experiments on the feeding of temperate salt marsh Foraminifera
Affiliation: Dalhousie University, Department of Earth Sciences, Halifax, NS, Canada
Pages: 259-274
Published: 201907
Text Language: English
Publisher: Cushman Foundation for Foraminiferal Research, Ithaca, NY, United States
References: 68
Accession Number: 2019-063848
Categories: Invertebrate paleontology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 3 tables
N44°42'00" - N44°42'00", W63°15'00" - W63°15'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Abstract, Copyright, Cushman Foundation for Foraminiferal Research. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 2019
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