scholarly journals Experimental Bleaching of a Reef-Building Coral Using a Simplified Recirculating Laboratory Exposure System

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Mace G. Barron ◽  
Cheryl J. McGill ◽  
Lee A. Courtney ◽  
Dragoslav T. Marcovich
Keyword(s):  
Solar Radiation ◽  
Tissue Loss ◽  
Pocillopora Damicornis ◽  
Critical Research ◽  
Solar Simulator ◽  
Exposure System ◽  
Symbiotic Algae ◽  
Coral Reef Ecosystems ◽  
Radiation Treatments ◽  
Laboratory Exposure

Determining stressor-response relationships in reef building corals continues to be a critical research need due to global declines in coral reef ecosystems and projected declines for the future. A simplified recirculating coral exposure system was coupled to a solar simulator to allow laboratory testing of a diversity of species and morphologies of reef building corals under ecologically relevant conditions of temperature and solar radiation. Combinations of lamps and attenuating filters allowed for assignment of solar radiation treatments in experimental bleaching studies. Three bleaching experiments were performed using the reef building coral,Pocillopora damicornis, to assess the reproducibility of system performance and coral responses under control and stress conditions. Experiments showed consistent temperature- and solar radiation dependent-changes in pigment, numbers of symbiotic algae, photosystem II quantum yield, and tissue loss during exposure and recovery. The laboratory exposure system is recommended for use in experimental bleaching studies with reef building corals.

scholarly journals Transient and Sustained Bacterial Adaptation following Repeated Sublethal Exposure to Microbicides and a Novel Human Antimicrobial Peptide

2014 ◽  
Vol 58 (10) ◽  
pp. 5809-5817 ◽  
Author(s):  
Sarah Forbes ◽  
Curtis B. Dobson ◽  
Gavin J. Humphreys ◽  
Andrew J. McBain
Keyword(s):  
Antimicrobial Peptide ◽  
Biofilm Formation ◽  
Bacterial Isolates ◽  
Exposure System ◽  
Polyhexamethylene Biguanide ◽  
Prevention And Treatment ◽  
Before And After ◽  
The Stability ◽  
Induced Changes ◽  
Laboratory Exposure

ABSTRACTMicrobicides (biocides) play an important role in the prevention and treatment of infections. While there is currently little evidence for in-use treatment failures attributable to acquired reductions in microbicide susceptibility, the susceptibility of some bacteria can be reduced by sublethal laboratory exposure to certain agents. In this investigation, a range of environmental bacterial isolates (11 genera, 18 species) were repeatedly exposed to four microbicides (cetrimide, chlorhexidine, polyhexamethylene biguanide [PHMB], and triclosan) and a cationic apolipoprotein E-derived antimicrobial peptide (apoEdpL-W) using a previously validated exposure system. Susceptibilities (MICs and minimum bactericidal concentrations [MBCs]) were determined before and after 10 passages (P10) in the presence of an antimicrobial and then after a further 10 passages without an antimicrobial to determine the stability of any adaptations. Bacteria exhibiting >4-fold increases in MBCs were further examined for alterations in biofilm-forming ability. Following microbicide exposure, ≥4-fold decreases in susceptibility (MIC or MBC) occurred for cetrimide (5/18 bacteria), apoEdpL-W (7/18), chlorhexidine (8/18), PHMB (8/18), and triclosan (11/18). Of the 34 ≥4-fold increases in the MICs, 15 were fully reversible, 13 were partially reversible, and 6 were nonreversible. Of the 26 ≥4-fold increases in the MBCs, 7 were fully reversible, 14 were partially reversible, and 5 were nonreversible. Significant decreases in biofilm formation in P10 strains occurred for apoEdpL-W (1/18 bacteria), chlorhexidine (1/18), and triclosan (2/18), while significant increases occurred for apoEdpL-W (1/18), triclosan (1/18), and chlorhexidine (2/18). These data indicate that the stability of induced changes in microbicide susceptibility varies but may be sustained for some combinations of a bacterium and a microbicide.

Calcified macroalgae and their bacterial community in relation to larval settlement and metamorphosis of reef-building coral Pocillopora damicornis

2020 ◽  
Vol 97 (1) ◽  
Author(s):  
Fangfang Yang ◽  
Jiahao Mo ◽  
Zhangliang Wei ◽  
Lijuan Long
Keyword(s):  
Bacterial Community ◽  
Community Composition ◽  
Bacterial Community Composition ◽  
Larval Settlement ◽  
Pocillopora Damicornis ◽  
Principal Coordinates Analysis ◽  
Principal Coordinates ◽  
Coral Reef Ecosystems ◽  
Settlement And Metamorphosis ◽  
Invertebrate Larvae

ABSTRACT Calcified macroalgae play an important role in the settlement and metamorphosis of invertebrate larvae in coral reef ecosystems. However, little is known about the algal-associated bacterial communities and their effects on larval settlement. In this study, the responses of larvae of the coral Pocillopora damicornis to calcified algae (Porolithon onkodes, Halimeda cylindracea, Halimeda opuntia and Amphiroa fragilissima) were evaluated. The results revealed that Por. onkodes and H. cylindracea significantly enhanced the rates of settlement and metamorphosis, whereas fewer larvae settled on Am. fragilissima and H. opuntia. Amplicon pyrosequencing of the V3–V4 region of 16S rDNA was applied to investigate the relationship between algal bacterial community and larval settlement. Principal coordinates analysis demonstrated that the bacterial community composition of H. opuntia was more similar to that of Am. fragilissima, but clearly distinct from those of H. cylindracea and Por. onkodes. Furthermore, the relative abundances of bacteria were highly diverse among different algae. H. opuntia had higher percentages of Thalassobius, Pelagibius and SM1A02, whereas the abundances of Mycoplasma and Suttonella were significantly higher in H. cylindracea than other algae. Our results showed that larval settlement/metamorphosis was strongly correlated with the bacterial community composition and with the relative abundance of a few operational taxonomic units.

scholarly journals The MILAN Campaign: Studying Diel Light Effects on the Air–Sea Interface

2020 ◽  
Vol 101 (2) ◽  
pp. E146-E166 ◽  
Author(s):  
Christian Stolle ◽  
Mariana Ribas-Ribas ◽  
Thomas H. Badewien ◽  
Jonathan Barnes ◽  
Lucy J. Carpenter ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Co2 Exchange ◽  
Sea Surface ◽  
Ex Situ ◽  
Surface Microlayer ◽  
Solar Simulator ◽  
Diel Cycles ◽  
Sea Surface Microlayer ◽  
Light Effects ◽  
Wind Intensity

Abstract The sea surface microlayer (SML) at the air–sea interface is <1 mm thick, but it is physically, chemically, and biologically distinct from the underlying water and the atmosphere above. Wind-driven turbulence and solar radiation are important drivers of SML physical and biogeochemical properties. Given that the SML is involved in all air–sea exchanges of mass and energy, its response to solar radiation, especially in relation to how it regulates the air–sea exchange of climate-relevant gases and aerosols, is surprisingly poorly characterized. MILAN (Sea Surface Microlayer at Night) was an international, multidisciplinary campaign designed to specifically address this issue. In spring 2017, we deployed diverse sampling platforms (research vessels, radio-controlled catamaran, free-drifting buoy) to study full diel cycles in the coastal North Sea SML and in underlying water, and installed a land-based aerosol sampler. We also carried out concurrent ex situ experiments using several microsensors, a laboratory gas exchange tank, a solar simulator, and a sea spray simulation chamber. In this paper we outline the diversity of approaches employed and some initial results obtained during MILAN. Our observations of diel SML variability show, for example, an influence of (i) changing solar radiation on the quantity and quality of organic material and (ii) diel changes in wind intensity primarily forcing air–sea CO2 exchange. Thus, MILAN underlines the value and the need of multidiciplinary campaigns for integrating SML complexity into the context of air–sea interaction.

The Effect of Simulated Solar Radiation on Western Corn Rootworm (Coleoptera: Chrysomelidae) Adults Fed D & C Red # 28, a Photoactive Xanthene Dye1

2002 ◽  
Vol 37 (3) ◽  
pp. 254-258
Author(s):  
Robert F. W. Schroder ◽  
Michael M. Athanas ◽  
Mary J. Camp
Keyword(s):  
Solar Radiation ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Corn Rootworm ◽  
Diabrotica Virgifera ◽  
Median Lethal Concentration ◽  
Exposure System ◽  
Lethal Time ◽  
Simulated Solar Radiation ◽  
Diabrotica Virgifera Virgifera Leconte

Western corn rootworm, Diabrotica virgifera virgifera LeConte, adults were fed a bitter Hawkesbury watermelon juice bait containing varying concentrations (0.00075–0.1%) of D & C Red # 28, a photoactive xanthene dye. Using a tabletop sunlight exposure system, the insects were irradiated at light intensities of 250–500 W/m2. At 500 W/m2 and 30 min exposure, a median lethal concentration (LC50) was obtained at a dye concentration of 0.00364%. At a dye concentration of 0.75%, the median lethal time (LT50) ranged from 24 min at 250 W/m2, to 15 min at 500 W/m2.

scholarly journals A laboratory exposure system to study the effects of aging on super-micron aerosol particles

2014 ◽  
Author(s):  
Joshua Santarpia ◽  
Andres L. Sanchez ◽  
Gabriel Anthony Lucero ◽  
Brandon Lee Servantes ◽  
Joshua Allen Hubbard
Keyword(s):  
Aerosol Particles ◽  
Exposure System ◽  
Effects Of Aging ◽  
Laboratory Exposure

Carbonaceous particles and stone damage in a laboratory exposure system

1996 ◽  
Vol 101 (D14) ◽  
pp. 19621-19627 ◽  
Author(s):  
C. Sabbioni ◽  
G. Zappia ◽  
G. Gobbi
Keyword(s):  
Exposure System ◽  
Carbonaceous Particles ◽  
Laboratory Exposure

scholarly journals Rapid Recruitment of Symbiotic Algae into Developing Scleractinian Coral Tissues

2019 ◽  
Vol 7 (9) ◽  
pp. 306
Author(s):  
Bockel ◽  
Rinkevich
Keyword(s):  
Tissue Expansion ◽  
Outer Edge ◽  
Tissue Growth ◽  
Coral Tissue ◽  
Coral Host ◽  
Pocillopora Damicornis ◽  
Stylophora Pistillata ◽  
Symbiotic Algae ◽  
Glass Slides ◽  
Host Tissues

While the early acquisition of Symbiodiniaceae algae into coral host tissues has been extensively studied, the dynamics of the migration of algal cells into rapidly expanding coral tissues still lacks a systematic study. This work examined two Red Sea branching coral species, Pocillopora damicornis and Stylophora pistillata, as they were growing and expanding their tissue laterally on glass slides (January–June, 2014; 450 assays; five colonies/species). We measured lateral tissue expansion rates and intratissue dinoflagellate migration rates. Tissue growth rates significantly differed between the two species (with Stylophora faster than Pocillopora), but not between genotypes within a species. Using a “flow-through coral chamber” under the microscope, the migration of dinoflagellates towards the peripheral edges of the expanding coral tissue was quantified. On a five-day timescale, the density of the endosymbiotic dinoflagellate cells, presenting within a 90 µm region of expanding coral tissue (outer edge), increased by a factor of 23.6 for Pocillopora (from 1.2 × 104 cells cm‒² to 2.4 × 105 cells cm‒²) and by a factor of 6.8 for Stylophora (from 3.6 × 104 cells cm‒² to 2.4 × 105 cells cm‒²). The infection rates were fast (5.2 × 104 and 4.1 × 104 algal cells day-1 cm‒², respectively), further providing evidence of an as yet unknown pathway of algal movement within coral host tissues.

scholarly journals Coral symbiotic algae calcifyex hospitein partnership with bacteria

2015 ◽  
Vol 112 (19) ◽  
pp. 6158-6163 ◽  
Author(s):  
Jörg C. Frommlet ◽  
Maria L. Sousa ◽  
Artur Alves ◽  
Sandra I. Vieira ◽  
David J. Suggett ◽  
...  
Keyword(s):  
Life History ◽  
Coral Reef ◽  
Evolutionary History ◽  
Central Importance ◽  
Free Living ◽  
Algal Communities ◽  
Symbiotic Algae ◽  
Coral Reef Ecosystems ◽  
History Of

Dinoflagellates of the genusSymbiodiniumare commonly recognized as invertebrate endosymbionts that are of central importance for the functioning of coral reef ecosystems. However, the endosymbiotic phase withinSymbiodiniumlife history is inherently tied to a more cryptic free-living (ex hospite) phase that remains largely unexplored. Here we show that free-livingSymbiodiniumspp. in culture commonly form calcifying bacterial–algal communities that produce aragonitic spherulites and encase the dinoflagellates as endolithic cells. This process is driven bySymbiodiniumphotosynthesis but occurs only in partnership with bacteria. Our findings not only place dinoflagellates on the map of microbial–algal organomineralization processes but also point toward an endolithic phase in theSymbiodiniumlife history, a phenomenon that may provide new perspectives on the biology and ecology ofSymbiodiniumspp. and the evolutionary history of the coral–dinoflagellate symbiosis.

scholarly journals Effects of ultraviolet radiation on photosynthetic performance and N<sub>2</sub> fixation in <i>Trichodesmium erythraeum</i> IMS 101

2017 ◽  
Vol 14 (19) ◽  
pp. 4455-4466 ◽  
Author(s):  
Xiaoni Cai ◽  
David A. Hutchins ◽  
Feixue Fu ◽  
Kunshan Gao
Keyword(s):  
Solar Radiation ◽  
Ultraviolet Radiation ◽  
Biological Effects ◽  
Photosynthetic Performance ◽  
Short Exposure ◽  
Effective Quantum Yield ◽  
Solar Simulator ◽  
Full Spectrum ◽  
Uv Irradiance ◽  
Oceanic Carbon

Abstract. Biological effects of ultraviolet radiation (UVR; 280–400 nm) on marine primary producers are of general concern, as oceanic carbon fixers that contribute to the marine biological CO2 pump are being exposed to increasing UV irradiance due to global change and ozone depletion. We investigated the effects of UV-B (280–320 nm) and UV-A (320–400 nm) on the biogeochemically critical filamentous marine N2-fixing cyanobacterium Trichodesmium (strain IMS101) using a solar simulator as well as under natural solar radiation. Short exposure to UV-B, UV-A, or integrated total UVR significantly reduced the effective quantum yield of photosystem II (PSII) and photosynthetic carbon and N2 fixation rates. Cells acclimated to low light were more sensitive to UV exposure compared to high-light-grown ones, which had more UV-absorbing compounds, most likely mycosporine-like amino acids (MAAs). After acclimation under natural sunlight, the specific growth rate was lower (by up to 44 %), MAA content was higher, and average trichome length was shorter (by up to 22 %) in the full spectrum of solar radiation with UVR, than under a photosynthetically active radiation (PAR) alone treatment (400–700 nm). These results suggest that prior shipboard experiments in UV-opaque containers may have substantially overestimated in situ nitrogen fixation rates by Trichodesmium, and that natural and anthropogenic elevation of UV radiation intensity could significantly inhibit this vital source of new nitrogen to the current and future oligotrophic oceans.

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