Effect of seawater temperature, pH, and nutrients on the distribution and character of low abundance shallow water benthic foraminifera in the Galápagos

• DOI: 10.1371/journal.pone.0202746
• Publication Date: 2018-09-12T13:52:02Z
• Authors: Alexander F. Hump...; Jochen Halfar; James C. Ingle; Derek Manzello; Claire E. Reymond; Hildegard Westphal; Bernhard Riegl
• Keywords: Archipelago

In order to help predict the effects of anthropogenic stressors on shallow water carbonate environments, it is important focus research regions containing natural oceanographic gradients, particularly with respect interactions between oceanography and ecologically sensitive producers. The Galápagos Archipelago, an island chain in eastern equatorial Pacific, spans a nutrient, pH, temperature gradient due interaction several major ocean currents. Further, region heavily impacted by El Niño—Southern Oscillation (ENSO) exhibited widespread coral bleaching degradation following strong ENSO events 1982–1983 1997–1998. These findings are coupled reports unusually low abundances time-averaged benthic foraminiferal assemblages throughout region. Foraminifera, shelled single-celled protists, environmental change rapidly respond alterations their surrounding environment, making them ideal indicator species for study reef quality health. Here, statistical models analyses were used compare modern from 19 samples spanning Archipelago predominant parameters at each collection site. Fisher α diversity indices, Ternary diagrams, Canonical Correspondence Analysis, regression tree analysis FORAM-Index (FI; single metric index evaluating associated development) implied combined impact upwelling Equatorial Undercurrent (EUC) waters primarily drive assemblage patterns archipelago. For instance, repeated anomalies might be responsible density, while chronically high nutrients aragonite saturation pH—induced EUC La Niña anomalies—likely inhibited post-ENSO recovery, caused exhibit heterotrophic dominance southern What resulted FI values sites, indicating environments not conducive endosymbiont development and/or recovery.