Distribution and seasonal variability in the benthic eukaryotic community of Río Tinto (SW, Spain), an acidic, high metal extreme environment

Author Posting. © The Author(s), 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Systematic and Applied Microbiology 30 (2007): 531-546, doi:10.1016/j.syapm.2007.05.003.The eukaryotic community of Río Tinto (SW, Spain) was surveyed fall, winter, and spring through the combined use of traditional microscopy and molecular approaches including Denaturing Gradient Gel Electrophoresis (DGGE) and sequence analysis of 18S rRNA gene fragments. We compared eukaryotic assemblages of surface sediment biofilms collected in January, May and September 2002 from 13 sampling stations along the river. Physicochemical data revealed extremely acidic conditions (pH ranged from 0.9 to 2.5) with high concentrations of heavy metals including up to 20 g l-1 Fe, 317 mg l-1 Zn, 47 mg l-1 As, 42 mg l-1 Cd, and 4 mg l-1 Ni. In total, 20 taxa were identified, including members of the Bacillariophyta, Chlorophyta, and Euglenophyta phyla as well as ciliates, cercomonads, amoebae, stramenopiles, fungi, heliozoan and rotifers. In general, total cell abundances were highest in fall and spring decreasing drastically in winter and the sampling stations with the most extreme conditions showed the lowest number of cells as well as the lowest diversity. Species diversity does not vary much during the year. Only the filamentous algae showed a dramatic seasonal change almost disappearing in winter and reaching the highest biomass during the summer. PCA showed a high inverse correlation between pH and most of the heavy metals analyzed as well as Dunaliella sp., while Chlamydomonas sp. is directly related to pH during May and September. Three heavy metals (Zn, Cu and Ni) remained separate from the rest and showed an inverse correlation with most of the species analyzed except for Dunaliella sp.A.A was supported by the Spanish Ministry of Education and Science through the Ramón y Cajal program. This work has been supported by grant CGL2005-05470/BOS and grants to the Centro de Astrobiología at the Instituto National de Técnica Aeroespacial

Comparative mitochondrial and chloroplast genomics of a genetically distinct form of Sargassum contributing to recent “Golden Tides” in the Western Atlantic

© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecology and Evolution 7 (2017): 516–525, doi:10.1002/ece3.2630.Over the past 5 years, massive accumulations of holopelagic species of the brown macroalga Sargassum in coastal areas of the Caribbean have created “golden tides” that threaten local biodiversity and trigger economic losses associated with beach deterioration and impact on fisheries and tourism. In 2015, the first report identifying the cause of these extreme events implicated a rare form of the holopelagic species Sargassum natans (form VIII). However, since the first mention of S. natans VIII in the 1930s, based solely on morphological characters, no molecular data have confirmed this identification. We generated full-length mitogenomes and partial chloroplast genomes of all representative holopelagic Sargassum species, S. fluitans III and S. natans I alongside the putatively rare S. natans VIII, to demonstrate small but consistent differences between S. natans I and VIII (7 bp differences out of the 34,727). Our comparative analyses also revealed that both S. natans I and S. natans VIII share a very close phylogenetic relationship with S. fluitans III (94- and 96-bp differences of 34,727). We designed novel primers that amplified regions of the cox2 and cox3 marker genes with consistent polymorphic sites that enabled differentiation between the two S. natans forms (I and VIII) from each other and both from S. fluitans III in over 150 Sargassum samples including those from the 2014 golden tide event. Despite remarkable gene synteny and sequence conservation, the three Sargassum forms differ in morphology, ecology, and distribution patterns, warranting more extensive interrogation of holopelagic Sargassum genomes as a whole.This work was supported by a US National Science Foundation (NSF) collaborative grant to LAA-Z (OCE-1155571) and ERZ (OCE-1155379), and an NSF TUES grant (DUE-1043468) to LAA-Z and ER

Biodegradable plastics in Mediterranean coastal environments feature contrasting microbial succession

Plastic pollution of the ocean is a top environmental concern. Biodegradable plastics present a potential “solution” in combating the accumulation of plastic pollution, and their production is currently increasing. While these polymers will contribute to the future plastic marine debris budget, very little is known still about the behavior of biodegradable plastics in different natural environments. In this study, we molecularly profiled entire microbial communities on laboratory confirmed biodegradable polybutylene sebacate-co-terephthalate (PBSeT) and polyhydroxybutyrate (PHB) films, and non-biodegradable conventional low-density polyethylene (LDPE) films that were incubated in situ in three different coastal environments in the Mediterranean Sea. Samples from a pelagic, benthic, and eulittoral habitat were taken at five timepoints during an incubation period of 22 months. We assessed the presence of potential biodegrading bacterial and fungal taxa and contrasted them against previously published in situ disintegration data of these polymers. Scanning electron microscopy imaging complemented our molecular data. Putative plastic degraders occurred in all environments, but there was no obvious “core” of shared plastic-specific microbes. While communities varied between polymers, the habitat predominantly selected for the underlying communities. Observed disintegration patterns did not necessarily match community patterns of putative plastic degraders

The biogeography of the Plastisphere : implications for policy

Author Posting. © Ecological Society of America, 2015. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Frontiers in Ecology and the Environment 13 (2015): 541–546, doi:10.1890/150017.Microplastics (particles less than 5 mm) numerically dominate marine debris and occur from coastal waters to mid-ocean gyres, where surface circulation concentrates them. Given the prevalence of plastic marine debris (PMD) and the rise in plastic production, the impacts of plastic on marine ecosystems will likely increase. Microscopic life (the “Plastisphere”) thrives on these tiny floating “islands” of debris and can be transported long distances. Using next-generation DNA sequencing, we characterized bacterial communities from water and plastic samples from the North Pacific and North Atlantic subtropical gyres to determine whether the composition of different Plastisphere communities reflects their biogeographic origins. We found that these communities differed between ocean basins – and to a lesser extent between polymer types – and displayed latitudinal gradients in species richness. Our research reveals some of the impacts of microplastics on marine biodiversity, demonstrates that the effects and fate of PMD may vary considerably in different parts of the global ocean, and suggests that PMD mitigation will require regional management efforts.This work was supported by a US National Science Foundation (NSF) collaborative grant to LAA-Z (OCE-1155571), ERZ (OCE-1155379), and TJM (OCE-1155671), and was partially funded by an NSF TUES grant (DUE-1043468) to LAA-Z and ERZ, and by the Richard Saltonstall Charitable Foundation to TJM. GP was funded through the OCE-1155379 grant and assisted with identification of plastic resins via ATR-FTIR

Influence of Central Pacific Oceanographic Conditions on the Potential Vertical Habitat of Four Tropical Tuna Species

Climate change has resulted in the geographic and vertical expansion of oxygen minimum zones but their impact on the vertical distribution of commercially important species, such as tunas, is not well understood. Although La Nina events are characterized by increased upwelling along the equator, the increased primary productivity and bacterial proliferation drive the expansion of oxygen minimum zones. Vertical habitat of four tropical tuna species were characterized using direct observations of the oceanographic conditions of the Central Pacific Ocean during the 2008 La Nina event and existing primary literature on temperature and dissolved oxygen physiological tolerances for these tunas. Concentrations of potential prey were estimated using Acoustic Doppler Current Profiler raw backscatter and surface zooplankton tows. Based on the oceanographic conditions observed from February to Tune, low dissolved oxygen levels, more so than low temperatures, were inferred to restrict the predicted vertical habitat of four commercially important tuna species (bigeye, yellowfin, skipjack, and albacore). During peak La Nina conditions, temperature and dissolved oxygen tolerance limits of all four tuna species were reached at approximately 200 m. Zooplankton and myctophid fish densities peaked in the upper 200 in between 0 degrees N and 5 degrees N, which corresponded to a region with a shallow thermochne (150 m). Our findings suggest the possibility that competition and susceptibility to surface fishing gears may be increased for tropical tunas during a strong La Nina event due to vertical habitat restrictions

Modeling submerged biofouled microplastics and their vertical trajectories

The fate of (micro)plastic particles in the open ocean is controlled by physical and biological processes. Here, we model the effects of biofouling on the subsurface vertical distribution of spherical, virtual plastic particles with radii of 0.01–1 mm. For the physics, four vertical velocity terms are included: advection, wind-driven mixing, tidally induced mixing, and the sinking velocity of the biofouled particle. For the biology, we simulate the attachment, growth and loss of algae on particles. We track 10,000 particles for one year in three different regions with distinct biological and physical properties: the low productivity region of the North Pacific Subtropical Gyre, the high productivity region of the Equatorial Pacific and the high mixing region of the Southern Ocean. The growth of biofilm mass in the euphotic zone and loss of mass below the euphotic zone result in the oscillatory behaviour of particles, where the larger (0.1–1.0 mm) particles have much shorter average oscillation lengths ( 5000 m). Our results show that the vertical movement of particles is mainly affected by physical (wind-induced mixing) processes within the mixed layer and biological (biofilm) dynamics below the mixed layer. Furthermore, positively buoyant particles with radii of 0.01–1.0 mm can sink far below the euphotic zone and mixed layer in regions with high near-surface mixing or high biological activity. This work can easily be coupled to other models to simulate open-ocean biofouling dynamics, in order to reach a better understanding of where ocean (micro)plastic ends up

Prospectus, April 26, 1977

VOTE TODAY-TOMORROW: FOUR VIE FOR PRES. IN STU-GO ELECTION; Remus, Mayeda run for V.P.; Albert Dodson unopposed; Activities Day May 3; Letters to the editor: Pres. Praises carnival, Mayeda warns of lies, Cartoon good…but, Stu-Go made many contributions: Onley; Editorial: Trouble for athletics; Hackett vs. Slack for convo., Cox opposes Stoeber for IOC; Unopposed: Propeck runs alone for secretary; Thursday set for wheel chair awareness; State provides funding for food sanitation course; Law Enforcement Club sponsors Mk\u27t Place fair; Markland: bigger not better for Twin City police force; Energy saving tips: Ripple effect causes waste; Police Chief Dye: \u27Recruitment-lifeline of police dep\u27t.\u27; Bike race today; Blooming Idiots come out of woodwork for IOC Carnival; Workshop set for Saturday: Puppetmaster Schmidt displays at PC; Afro American Theatre Workshop starts at PC; \u27Alcohol, sophisticated, sexy?\u27; Bike tour Sunday, May 1; Classifieds; Bat girls provide needed help for baseball team; Cobras expand record with 3rd no-hitter; Lincolnland doubleheader tomorrow: Women\u27s softball season nears end; June 7-10: Mudrock headed to JC golf nationalshttps://spark.parkland.edu/prospectus_1977/1018/thumbnail.jp

Computing marine plankton connectivity under thermal constraints

Ocean currents are a key driver of plankton dispersal across the oceanic basins. However, species specific temperature constraints may limit the plankton dispersal. We propose a methodology to estimate the connectivity pathways and timescales for plankton species with given constraints on temperature tolerances, by combining Lagrangian modeling with network theory. We demonstrate application of two types of temperature constraints: thermal niche and adaptation potential and compare it to the surface water connectivity between sample stations in the Atlantic Ocean. We find that non-constrained passive particles representative of a plankton species can connect all the stations within three years at the surface with pathways mostly along the major ocean currents. However, under thermal constraints, only a subset of stations can establish connectivity. Connectivity time increases marginally under these constraints, suggesting that plankton can keep within their favorable thermal conditions by advecting via slightly longer paths. Effect of advection depth on connectivity is observed to be sensitive to the width of the thermal constraints, along with decreasing flow speeds with depth and possible changes in pathways

Modelling submerged biofouled microplastics and their vertical trajectories

The fate of (micro)plastic particles in the open ocean is controlled by biological and physical processes. Here, we model the effects of biofouling on the subsurface vertical distribution of spherical, virtual plastic particles with radii of 0.01–1 mm. The biological specifications include the attachment, growth and loss of algae on particles. The physical specifications include four vertical velocity terms: advection, wind-driven mixing, tidally induced mixing and the sinking velocity of the biofouled particle. We track 10 000 particles for 1 year in three different regions with distinct biological and physical properties: the low-productivity region of the North Pacific Subtropical Gyre, the high-productivity region of the equatorial Pacific and the high mixing region of the Southern Ocean. The growth of biofilm mass in the euphotic zone and loss of mass below the euphotic zone result in the oscillatory behaviour of particles, where the larger (0.1–1.0 mm) particles have much shorter average oscillation lengths (5000 m). Our results show that the vertical movement of particles is mainly affected by physical (wind-induced mixing) processes within the mixed-layer and biological (biofilm) dynamics below the mixed layer. Furthermore, positively buoyant particles with radii of 0.01–1.0 mm can sink far below the euphotic zone and mixed layer in regions with high near-surface mixing or high biological activity. This work can easily be coupled to other models to simulate open-ocean biofouling dynamics, in order to reach a better understanding of where ocean (micro)plastic ends up

Contrasting Microbial Community Assembly Hypotheses: A Reconciling Tale from the Río Tinto

The Río Tinto (RT) is distinguished from other acid mine drainage systems by its natural and ancient origins. Microbial life from all three domains flourishes in this ecosystem, but bacteria dominate metabolic processes that perpetuate environmental extremes. While the patchy geochemistry of the RT likely influences the dynamics of bacterial populations, demonstrating which environmental variables shape microbial diversity and unveiling the mechanisms underlying observed patterns, remain major challenges in microbial ecology whose answers rely upon detailed assessments of community structures coupled with fine-scale measurements of physico-chemical parameters.By using high-throughput environmental tag sequencing we achieved saturation of richness estimators for the first time in the RT. We found that environmental factors dictate the distribution of the most abundant taxa in this system, but stochastic niche differentiation processes, such as mutation and dispersal, also contribute to observed diversity patterns.We predict that studies providing clues to the evolutionary and ecological processes underlying microbial distributions will reconcile the ongoing debate between the Baas Becking vs. Hubbell community assembly hypotheses