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Is biodiversity energy-limited or unbounded? A test in fossil and modern bivalves

Craig R. McClain, Noel A. Heim, Matthew L. Knope and Jonathan L. Payne
Is biodiversity energy-limited or unbounded? A test in fossil and modern bivalves
Paleobiology (August 2018) 44 (3): 385-401


The quantity of biomass in an ecosystem is constrained by energy availability. It is less clear, however, how energy availability constrains taxonomic and functional diversity. Competing models suggest biodiversity is either resource-limited or far from any bound. We test the hypothesis that functional diversity in marine bivalve communities is constrained by energy availability, measured as particulate organic carbon (POC) flux, in the modern oceans. We find that POC flux predicts the relative prevalence of ecological modes in both the Atlantic and Pacific Oceans. Moreover, the associations of ecological modes with POC fluxes are similar between the Atlantic and Pacific despite being based on independent sets of species, indicating a direct causal relationship. We then use the relationship between POC flux and the prevalence of functional groups in the modern to test the hypothesis that the trend of increasing functional diversity in bivalves across the past 500 Myr has occurred in response to increased POC flux. We find no evidence that the earliest-appearing modes of life are preferentially associated with low-POC environments or that the mean POC flux experienced by marine bivalves has increased across geological time. To reconcile the close association between ecological mode and POC flux in the modern oceans with the lack of evidence for increasing POC fluxes across time, we propose that POC flux has not increased substantially over time but, rather, the increase in bivalve functional diversity enabled bivalves to become more abundant, to occupy a broader range of environments, and to capture a greater fraction of the total POC flux. The results here suggest at the geographic scale of oceans and through geologic time bivalve diversity was not bounded by food availability.

ISSN: 0094-8373
EISSN: 1938-5331
Serial Title: Paleobiology
Serial Volume: 44
Serial Issue: 3
Title: Is biodiversity energy-limited or unbounded? A test in fossil and modern bivalves
Affiliation: Louisiana Universities Marine Consortium, Chauvin, LA, United States
Pages: 385-401
Published: 201808
Text Language: English
Publisher: Paleontological Society, Lawrence, KS, United States
References: 77
Accession Number: 2019-003797
Categories: Invertebrate paleontology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: NSF Grant EAR-1151022
Illustration Description: illus. incl. 1 table
Secondary Affiliation: Stanford University, USA, United StatesUniversity of Hawaii at Hilo, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Abstract, Copyright, The Paleontological Society. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201902
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