Consumers can influence ecological patterns and processes through their trophic roles and contributions to the flow of energy through ecosystems. However, the diet and associated trophic roles of consumers commonly change during ontogeny. Despite the prevalence of ontogenetic variation in trophic roles of most animals, we lack an understanding of whether they change consistently across local populations and broad geographic gradients.
View Article and Find Full Text PDFThe Florida Horse Conch, Triplofusus giganteus, one of the largest marine gastropods in the world, has been intensely exploited by shell collectors, curio dealers, and commercial harvest for over a century and is now in decline. Effective management of horse conch populations requires better data on commercial and recreational harvest intensities but also on the species' intrinsic capacity to recover. Here, we use stable oxygen and carbon isotope sclerochronology to investigate the horse conch's life history, including its maximum life span, growth rates, age at first spawning, and number of lifetime spawning seasons.
View Article and Find Full Text PDFGenome and proteome data predict the presence of both the reductive citric acid cycle (rCAC; also called the reductive tricarboxylic acid cycle) and the Calvin-Benson-Bassham cycle (CBB) in " Endoriftia persephonae," the autotrophic sulfur-oxidizing bacterial endosymbiont from the giant hydrothermal vent tubeworm Riftia pachyptila. We tested whether these cycles were differentially induced by sulfide supply, since the synthesis of biosynthetic intermediates by the rCAC is less energetically expensive than that by the CBB. R.
View Article and Find Full Text PDFFollowing the Deepwater Horizon (DWH) event in 2010, hydrocarbons were deposited on the continental slope in the northeastern Gulf of Mexico through marine oil snow sedimentation and flocculent accumulation (MOSSFA). The objective of this study was to test the hypothesis that benthic foraminiferal δC would record this depositional event. From December 2010 to August 2014, a time-series of sediment cores was collected at two impacted sites and one control site in the northeastern Gulf of Mexico.
View Article and Find Full Text PDFAquatic sediment core subsampling is commonly performed at cm or half-cm resolution. Depending on the sedimentation rate and depositional environment, this resolution provides records at the annual to decadal scale, at best. An extrusion method, using a calibrated, threaded-rod is presented here, which allows for millimeter-scale subsampling of aquatic sediment cores of varying diameters.
View Article and Find Full Text PDFThe Atlantic Goliath Grouper, Epinephelus itajara, is critically endangered throughout its range but has begun to show initial signs of recovery in Florida state waters. As the population continues to rebound, researchers face a pressing need to fill the knowledge gaps about this iconic species. Here, we examined the δ (15)N isotopic records in fin rays collected from Atlantic Goliath Grouper, and related changes of isotopic ratios over time to life history characteristics.
View Article and Find Full Text PDFThe Deepwater Horizon (DWH) spill released 4.9 million barrels of oil into the Gulf of Mexico (GoM) over 87 days. Sediment and water sampling efforts were concentrated SW of the DWH and in coastal areas.
View Article and Find Full Text PDFThe blowout of the Deepwater Horizon (DWH) drill-rig produced a surface oil layer, dispersed micro-droplets throughout the water column, and sub-surface plumes. We measured stable carbon and nitrogen isotopes in mesopelagic fishes and shrimps in the vicinity of DWH collected prior to, six weeks after, and one year after the oil spill (2007, 2010 and 2011). In 2010, the year of the oil spill, a small but significant depletion of δ(13)C was found in two mesopelagic fishes (Gonostoma elongatum and Chauliodus sloani) and one shrimp (Systellaspis debilis); a significant δ(15)N enrichment was identified in the same shrimp and in three fish species (G.
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