DOI: 10.5061/dryad.d5p86fp
title: Data from: Environmental influence on growth history in marine benthic foraminifera

description: Energy availability influences natural selection on the ontogenetic
 histories of organisms. However, it remains unclear if physiological
 controls on size remain constant throughout ontogeny or instead shift as
 organisms grow larger. Benthic foraminifera provide an opportunity to
 quantify and interpret the physicochemical controls on both initial
 (proloculus) and adult volumes across broad environmental gradients using
 first principles of cell physiology. Here, we measured proloculus and
 adult test dimensions of 129 modern rotaliid species from published images
 of holotype specimens using holotype size to represent the maximum size of
 all species’ occurrences across the North American continental margin. We
 merged size data with mean annual temperature, dissolved oxygen
 concentration, particulate organic carbon flux, and seawater calcite
 saturation for 718 unique localities to quantify the relationship between
 physicochemical variables and among-species adult/proloculus size ratios.
 We find that correlation of community mean adult/proloculus size ratios
 with environmental parameters reflects co-variation of adult test volume
 with environmental conditions. Among-species proloculus sizes do not
 co-vary identifiably with environmental conditions, consistent with the
 expectation that environmental constraints on organism size impose
 stronger selective pressures on adult forms due to lower surface
 area-to-volume ratios at larger sizes. Among-species adult/proloculus size
 ratios of foraminifera occurring in resource-limited environments are
 constrained by the limiting resource in addition to temperature.
 Identified limiting resources are food in oligotrophic waters and oxygen
 in oxygen minimum zones. Because among-species variations in
 adult/proloculus size ratios from the North American continental margin
 are primarily driven by the local environment’s influence on adult sizes,
 the evolution of foraminiferal sizes over the Phanerozoic may have been
 strongly influenced by changing oceanographic conditions. Furthermore,
 lack of correspondence between among-species proloculus sizes and
 environmental conditions suggests that offspring size in foraminifera are
 rarely limited by physiological constraints and are more susceptible to
 selection related to other aspects of fitness.
description: Keating-Bitonti&Payne_FigureS1Figure S1. (A) Results of L1-regularized regression analysis assessing the correlations between environmental predictors and log adult/proloculus size ratios for Atlantic endemic species. Plots B-E show the relationship between Atlantic endemic species’ log adult/proloculus size ratios to local temperature, oxygen, calcite saturation, and oxygen, respectively, with solid black lines representing the linear regression of these data. The L1-regularized regression analysis identified that temperature alone best predicts the log adult/proloculus size ratios of Atlantic endemics and the plot B supports this result with the largest R2 value compared to the other environmental variables (see Table S1).Keating-BitontiFigureS1_1col.epsKeating-Bitonti-SITables-05.01.18Supplemental Tables S1 and S2