Functional diversity of living benthic foraminifera of the southeastern Pacific Ocean and their relationship with environmental variables
Vicente, K.S. (2026). Functional diversity of living benthic foraminifera of the southeastern Pacific Ocean and their relationship with environmental variables. MSc Thesis. Universidad de Concepción: Concepción. 165 pp.
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Document type: Dissertation
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Benthic foraminifera, functional diversity, functional traits, niche, Southeastern Pacific |
| Abstract |
Benthic foraminifera are key indicators that provide insights into ecosystem functioning through their adaptations to environmental gradients. This study assesses the taxonomic and functional diversity of living benthic foraminiferal communities along the western South American continental margin (1°–50°S) and water depths from 79 to 4500 m. A total of 365 species were identified, with Rotalida, Lituolida, and Astrorhizida as the most frequent orders. Species richness and diversity exhibited pronounced spatial variability structured not by a continuous latitudinal gradient, but by discrete environmental thresholds, primarily associated with oxygen availability. Functional diversity analyses revealed that taxonomically richer communities occupied broader functional trait space, though unevenly across the study area, indicating substantial functional redundancy. This pattern emerged under environmental filtering, particularly in highly diverse assemblages where partial saturation of trait space occurred. In contrast, heterogeneous sectors promoted greater niche differentiation and functional diversification. Community-weighted mean traits revealed consistent latitudinal shifts in morphology, trophic strategies, and oxygen tolerance. Generalized additive models identified temperature, salinity, oxygen, phosphate, silicate concentrations, and sediment characteristics as drivers of taxonomic and functional diversity, with oxygen emerging as the dominant structuring factor. Niche analyses were consistent with environmental filtering under oxygen-depleted conditions, where communities were dominated by specialists occupying marginal niches. Our results demonstrate that oxygen availability regulates species distributions, niche configuration, and functional organization, modulating the balance between redundancy and differentiation in benthic ecosystems of the Southeastern Pacific. This study establishes a regional baseline to assess ecological consequences of continued OMZ expansion in the Southeastern Pacific. |
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