QUANTIFYING BENTHIC TUBULAR AGGLUTINATED FORAMINIFERA: A NEW APPROACH

Tubular agglutinated taxa are epifaunal, generally regarded as opportunistic, and are associated with areas which receive a high amount of organic carbon flux. Therefore, obtaining accurate abundance and count data for these forms within benthic foraminiferal assemblages is imperative for both modern ecological studies and paleoenvironmental interpretations. . Recent tubular agglutinated foraminiferal specimens from a sediment core collected in the northeastern Gulf of Mexico (WB-1110-DSH10-ISO) are quantified using the method proposed in this work and three other methodologies found in published literature in order to compare and contrast quantitative results.

Tubular agglutinated foraminifera are relatively large, with unilocular or branching morphology. Genera of this morphogroup include Bathysiphon, Rhabdammina, Rhizammina, Sacchoriza, and Hyperammina. The tests are often composed of cemented coarse- to fine-grained sediment or detritus. Due to the fragility of their tests, it is not unusual to recover individual specimens in several fragments, confusing counts of individuals. Further, the intraspecies variation in dimension and size within these genera often making it difficult to obtain count data without overestimating or underestimating values. In this work we take a simple and previously undocumented approach to quantify these forms to make the attempt to obtain greater accuracy within assemblage samples. In each sample, tubular agglutinated foraminiferal fragments were measured and quantified based on the length of a model or baseline specimen. Ultimately, this study will contribute to the growing body of work on quantifying tubular agglutinated foraminifera accurately despite often recovering incomplete, fragmented individuals.