Pelagic Sargassum as an emergent high-rate importer of carbonate sediment to tropical Atlantic coastlines

2021 ◽  
Author(s):  
Michael Salter ◽  
Chris Perry ◽  
Rosa Rodríguez-Martínez ◽  
Lorenzo Alvarez-Filip ◽  
Eric Jordan-Dahlgren
Keyword(s):  
Large Scale ◽  
Coastal Sediments ◽  
High Rate ◽  
Carbonate Content ◽  
Tropical Atlantic ◽  
Carbonate Sediments ◽  
Carbonate Sediment ◽  
Carbonate Production ◽  
Mexican Caribbean ◽  
Epiphytic Communities

<p>The composition of modern carbonate sediments in nearshore tropical marine settings typically reflects a suite of somewhat proximal processes of carbonate production and erosion. Here, we document pelagic <em>Sargassum</em> as an emergent vector of carbonate sediment import to tropical Atlantic and Caribbean shorelines: a process with distal (oceanic) origins that has the potential to impart a distinct record of regional to global change within nearshore sediments. This process arose as recently as 2011, when a major new <em>Sargassum</em> bloom region emerged in the central Atlantic Ocean and resulted in Caribbean, West African, and northern Brazilian shorelines being inundated with <em>Sargassum</em> at unprecedented scales. Subsequent near annual recurrences of these coastal inundations at increasingly large scales suggest they are becoming an established norm. Socio-economic and ecological implications are widespread and potentially serious, and include potential impacts on the established sources and stability of nearshore carbonate sediments. This study, however, focuses on new sediment delivered to these coastal settings in the form of calcareous epiphytic communities that colonise <em>Sargassum</em> (i.e., bryozoans, serpulid worms, and red algae). Our analysis of <em>Sargassum</em> collected from coastal waters of the Mexican Caribbean in 2018 indicates a mean carbonate content of 2.09% wet weight at shoreline arrival. Based on data from 11 sites in Quintana Roo, Mexico (spanning 11.15 km of a 60 km section of shoreline), we further estimate the average drained weight of <em>Sargassum</em> that arrived at the coast during 2018 to have been 7.0x10<sup>3</sup> kg m<sup>-1</sup> of shoreline. Together, these findings indicate that mean import of new carbonate sediment by <em>Sargassum</em> was 179 kg m<sup>-1</sup> of shoreline in 2018, which is close to our upper estimate of annual proximal sediment production by <em>Thalassia</em> seagrass epiphytes (210 kg m<sup>-1</sup> of shoreline). Prior to the onset of these massive <em>Sargassum</em> inundations, grains recognisable as bryozoan skeletons and serpulid tube casings were rare in coastal sediments of the Mexican Caribbean. Consequently, if these calcareous <em>Sargassum</em> epiphytes that are evidently now being imported in large volumes are retained and preserved, they can be expected to impart a distinct record within these coastal sediments. Although quantitative data on <em>Sargassum</em> inundations from other locations are sparse, numerous reports from the scientific community and the media suggest the scale of these events is comparable for many exposed tropical Caribbean and Atlantic shorelines. This represents the first documentation of pelagic <em>Sargassum</em> as a major vector of coastal sediment import, the significance of which has likely only arisen since the onset of large-scale inundations in 2011.</p>

Pelagic Sargassum as an emerging vector of high rate carbonate sediment import to tropical Atlantic coastlines

2020 ◽  
Vol 195 ◽  
pp. 103332 ◽  
Author(s):  
Michael A. Salter ◽  
Rosa E. Rodríguez-Martínez ◽  
Lorenzo Álvarez-Filip ◽  
Eric Jordán-Dahlgren ◽  
Chris T. Perry
Keyword(s):  
High Rate ◽  
Tropical Atlantic ◽  
Carbonate Sediment

scholarly journals High-Rate Transition Metal-based Cathode Materials for Battery-Supercapacitor Hybrid Devices

2021 ◽  
Author(s):  
Cong Wang ◽  
Zehao Song ◽  
Pei Shi ◽  
Lin Lv ◽  
Houzhao Wan ◽  
...  
Keyword(s):  
Large Scale ◽  
Rapid Development ◽  
Electronic Devices ◽  
High Rate ◽  
Specific Power ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Electrochemical Devices ◽  
Hybrid Devices ◽  
Scale Grid

With the rapid development of portable electronic devices, electric vehicles and large-scale grid energy storage devices, it needs to reinforce specific energy and specific power of related electrochemical devices meeting...

scholarly journals Rapid evolution at the Drosophila telomere: transposable element dynamics at an intrinsically unstable locus

Genetics ◽  
2020 ◽  
Vol 217 (2) ◽  
Author(s):  
Michael P McGurk ◽  
Anne-Marie Dion-Côté ◽  
Daniel A Barbash
Keyword(s):  
Copy Number ◽  
Large Scale ◽  
Insertion Site ◽  
Rapid Evolution ◽  
Interspecific Variation ◽  
High Rate ◽  
Evolutionary Strategy ◽  
Control Mechanisms ◽  
Genetic Conflict ◽  
Number Variation

AbstractDrosophila telomeres have been maintained by three families of active transposable elements (TEs), HeT-A, TAHRE, and TART, collectively referred to as HTTs, for tens of millions of years, which contrasts with an unusually high degree of HTT interspecific variation. While the impacts of conflict and domestication are often invoked to explain HTT variation, the telomeres are unstable structures such that neutral mutational processes and evolutionary tradeoffs may also drive HTT evolution. We leveraged population genomic data to analyze nearly 10,000 HTT insertions in 85  Drosophila melanogaster genomes and compared their variation to other more typical TE families. We observe that occasional large-scale copy number expansions of both HTTs and other TE families occur, highlighting that the HTTs are, like their feral cousins, typically repressed but primed to take over given the opportunity. However, large expansions of HTTs are not caused by the runaway activity of any particular HTT subfamilies or even associated with telomere-specific TE activity, as might be expected if HTTs are in strong genetic conflict with their hosts. Rather than conflict, we instead suggest that distinctive aspects of HTT copy number variation and sequence diversity largely reflect telomere instability, with HTT insertions being lost at much higher rates than other TEs elsewhere in the genome. We extend previous observations that telomere deletions occur at a high rate, and surprisingly discover that more than one-third do not appear to have been healed with an HTT insertion. We also report that some HTT families may be preferentially activated by the erosion of whole telomeres, implying the existence of HTT-specific host control mechanisms. We further suggest that the persistent telomere localization of HTTs may reflect a highly successful evolutionary strategy that trades away a stable insertion site in order to have reduced impact on the host genome. We propose that HTT evolution is driven by multiple processes, with niche specialization and telomere instability being previously underappreciated and likely predominant.

Dissolution and recrystallization in modern shelf carbonates: evidence from pore water and solid phase chemistry

1993 ◽  
Vol 344 (1670) ◽  
pp. 27-36 ◽  
Keyword(s):  
Organic Matter ◽  
Pore Water ◽  
Solid Phase ◽  
Chemical Exchange ◽  
Isotope Composition ◽  
Geochemical Data ◽  
Carbonate Sediments ◽  
Pore Waters ◽  
Carbonate Minerals ◽  
Carbonate Production

We present an overview of geochemical data from pore waters and solid phases that clarify earliest diagenetic processes affecting modern, shallow marine carbonate sediments. Acids produced by organic matter decomposition react rapidly with metastable carbonate minerals in pore waters to produce extensive syndepositional dissolution and recrystallization. Stoichiometric relations among pore water solutes suggest that dissolution is related to oxidation of H 2 S which can accumulate in these low-Fe sediments. Sulphide oxidation likely occurs by enhanced diffusion of O 2 mediated by sulphide-oxidizing bacteria which colonize oxic/anoxic interfaces invaginating these intensely bioturbated sediments. Buffering of pore water stable isotopic compositions towards values of bulk sediment and rapid 45 Ca exchange rates during sediment incubations demonstrate that carbonate recrystallization is a significant process. Comparison of average biogenic carbonate production rates with estimated rates of dissolution and recrystallization suggests that over half the gross production is dissolved and/or recrystallized. Thus isotopic and elemental composition of carbonate minerals can experience significant alteration during earliest burial driven by chemical exchange among carbonate minerals and decomposing organic matter. Temporal shifts in palaeo-ocean carbon isotope composition inferred from bulk-rocks may be seriously compromised by facies-dependent differences in dissolution and recrystallization rates.

scholarly journals Community structure and carbonate production of a temperate rhodolith bank from Arvoredo Island, southern Brazil

2004 ◽  
Vol 52 (3-4) ◽  
pp. 207-224 ◽  
Author(s):  
Douglas F. M. Gherardi
Keyword(s):  
Community Structure ◽  
Coralline Algae ◽  
Carbonate Content ◽  
Production Rates ◽  
Percentage Cover ◽  
Coralline Red Algae ◽  
Carbonate Production ◽  
Random Dispersal ◽  
Long Run ◽  
Main Bank

A small (100,000 m²) rhodolith bank located at the Arvoredo Marine Biological Reserve (Santa Catarina, Brazil) has been surveyed to determine the main bank components, the community structure, and carbonate production rates. Data from five photographic transects perpendicular to Arvoredo Island shore were complemented with sediment samples and shallow cores, all collected by scuba diving. The main bank component is the unattached, nongeniculate, coralline red algae Lithophyllum sp., used as substrate by the zoanthid Zoanthus sp. Percentage cover of living and dead coralline algae, zoanthids and sediment patches account for nearly 98% of the investigated area. Classification and ordination of samples showed that differences in the proportion of live and dead thalli of Lithophyllum sp. determine the relative abundances of zoanthids. Results also indicate that similarity of samples is high and community gradients are subtle. Significant differences in percentage cover along transects are concentrated in the central portion of the bank. Low carbonate content of sediments from deeper samples suggests low rates of recruitment and dispersal of coralline algae via fragmentation. However, carbonate production of Lithophyllum sp ranging from 55-136.3 g m-2 yr-1 agrees with production rates reported for other temperate settings. In the long run, rhodolith density at Arvoredo Is. is likely to be dependent upon random dispersal of spores and/or fragments from other source areas.

Neurofeedback for Opioid Dependent Patients in an Outpatient Setting: A Pilot Feasibility Study

2021 ◽  
Author(s):  
Helena A. Rempala ◽  
Justin A. Barterian
Keyword(s):  
Large Scale ◽  
The United States ◽  
Outpatient Setting ◽  
Opioid Use Disorder ◽  
High Rate ◽  
Treatment Center ◽  
Opioid Use ◽  
Treatment As Usual ◽  
Factors Affecting ◽  
Study Approach

Abstract Background: Neurofeedback (NF) has been described as “probably efficacious” when used in conjunction with other interventions for substance use disorders, including the most recent studies in population of individuals with opioid use disorder. Despite these promising outcomes, the seriousness of the opioid epidemic, and the high rate of relapse even with the most effective medication-assisted maintenance treatments NF continues to be an under-researched treatment modality. This article explores factors that affected the feasibility of adding Alpha/Theta Neurofeedback to treatment as usual for opioid dependence in an outpatient urban treatment center. The study strived to replicate previous research completed in Iran that found benefits of NF for opioid dependence.Methods: Out of approximately two dozen patients eligible for Alpha/Theta NF, about 60% (n=15) agreed to participate; however, only 2 participants completed treatment. The rates of enrollment in response to active treatment were monitored. Results: The 4 factors affecting feasibility were: 1) the time commitment required of participants, 2) ineffectiveness of standard incentives to promote participation, 3) delayed effects of training, and 4) the length and number of treatments required.Conclusion: The findings indicate a large scale study examining the use of NF for the treatment of opioid use disorder in the United States will likely be difficult to accomplish without modification to the traditional randomized control study approach and suggests challenges to the implementation of this treatment in an outpatient setting.

scholarly journals Comparison of cnidae sizes between the two morphotypes of the giant Caribbean sea anemone Condylactis gigantea (Actiniaria: Actiniidae)

2018 ◽  
Vol 66 (3) ◽  
pp. 1055
Author(s):  
Ricardo Enrique González Muñoz ◽  
Carlos Hernández-Ortiz ◽  
Agustin Garese ◽  
Nuno Simões ◽  
Fabián Horacio Acuña
Keyword(s):  
Coral Reefs ◽  
Gulf Of Mexico ◽  
Related Species ◽  
Significant Variation ◽  
Caribbean Sea ◽  
Sea Anemone ◽  
Tropical Atlantic ◽  
Closely Related Species ◽  
Mexican Caribbean ◽  
Ecological Differences

The sea anemone Condylactis gigantea is an ecologically important member of the benthic community in coral reefs of the tropical Atlantic, and displays two morphotypes with respect to the color in their tentacular tips: the green tip morphotype and the pink/purple tip morphotype. Although some molecular and ecological differences have been found between these morphotypes, no other morphological distinctions have been reported, and currently both are still considered a single taxonomic species. In the present study, we perform an exploration on the variability in the size of cnidae between these two morphotypes and performed statistical analyses to compare the 10 categories of cnidae from specimens hosted in the Cnidarian Collection of Gulf of Mexico and Mexican Caribbean, of the Universidad Nacional Autónoma de México, which were previously collected in several coral reefs localities of the Yucatán Peninsula. Results reveal no significant variation in cnidae size between the two morphotypes, but significant variations were found within each morphotype. In addition, we update the composition of the cnidom of C. gigantea, and the utility of the size of cnidae to distinguish between morphotypes or closely related species is discussed.

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