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The organisms thriving under extreme conditions better than any other organism living on Earth, fascinate by their hostile growing parameters, physiological features, and their production of valuable bioactive metabolites. This is the case of microorganisms (bacteria, archaea, and fungi) that grow optimally at high salinities and are able to produce biomolecules of pharmaceutical interest for therapeutic applications. As along as the microbiota is being approached by massive sequencing, novel insights are revealing the environmental conditions on which the compounds are produced in the microbial community without more stress than sharing the same substratum with their peers, the salt. In this review are reported the molecules described and produced by halophilic microorganisms with a spectrum of action in vitro: antimicrobial and anticancer. The action mechanisms of these molecules, the urgent need to introduce alternative lead compounds and the current aspects on the exploitation and its limitations are discussed.

Biofilm cultivation is considered a promising method to achieve higher microalgae biomass productivity with less water consumption and easier harvest compared to conventional suspended cultivation. However, studies focusing on the selection of substratum material and optimization of the growth of certain microalgae species on specific substratum are limited. This study investigated the selection of membranous and fabric fiber substrata for the attachment of unicellular microalgae Scenedesmus dimorphus and filamentous microalgae Tribonema minus in biofilm cultivation. The results indicated that both algal species preferred hydrophilic membranous substrata and nitrate cellulose/cellulose acetate membrane (CN-CA) was selected as a suitable candidate on which the obtained biomass yields were up to 10.24 and 7.81 g m−2 day−1 for S. dimorphus and T. minus, respectively. Furthermore, high-thread cotton fiber (HCF) and low-thread polyester fiber (LPEF) were verified as the potential fabric fiber substrata for S. dimorphus (5.42 g m−2 day−1) and T. minus (5.49 g m−2 day−1) attachment, respectively. The regrowth of microalgae biofilm cultivation strategy was applied to optimize the algae growth on the fabric fiber substrata, with higher biomass density and shear resistibility achieved for both algal species. The present data highlight the importance to establish the standards for selection the suitable substratum materials in ensuring the high efficiency and sustainability of the attached microalgal biomass production.Key points• CN-CA was suitable membranous substratum candidate for algal biofilm cultivation.• HCF and LPEF were potential fabric fiber substrata for S. dimorphus and T. minus.• Regrowth biofilm cultivation was effective in improving algal biomass and attachment.

Surface colonization in seawater first corresponds to the selection of specific microbial biofilm communities. By coupling flow cytometry, microscopy and high throughput sequencing (HTS, 454 pyrosequencing) with artificial surfaces and environmental analyses, we intend to identify the contribution of biofilm community drivers at two contrasted French sites, one temperate and eutrophic (Lorient, Atlantic coast) and the other at a mesotrophic but highly contaminated bay (Toulon, North-Western Mediterranean Sea). Microbial communities were shaped by high temperatures, salinity and lead at Toulon by but nutrients and DOC at Lorient. Coatings including pyrithione exhibited a significant decrease of their microbial densities except for nanoeukaryotes. Clustering of communities was mainly based on the surface type and secondly the site, whereas seasons appeared of less importance. The in-depth HTS revealed that γ- and α-proteobacteria, but also Bacteroidetes, dominated highly diversified bacterial communities with a relative low β-diversity. Sensitivity to biocides released by the tested antifouling coatings could be noticed at different taxonomic levels: the percentage of Bacteroidetes overall decreased with the presence of pyrithione, whereas the α/γ-proteobacteria ratio decreased at Toulon when increased at Lorient. Small diatom cells (Amphora and Navicula spp.) dominated on all surfaces, whereas site-specific sub-dominant taxa appeared clearly more sensitive to biocides. This overall approach exhibited the critical significance of surface characteristics in biofilm community shaping.

Parrotfishes (Scarini) are considered key agents in coral reef health and recovery, but the drivers of parrotfish–coral dynamics remain contentious. The prevailing view of parrotfishes as ecosystem engineers is based on the perceived removal of algal turf, macroalgae and sediment, but these are effects of feeding, not causes. The recent proposal that most parrotfishes are ‘microphages’ that target microscopic photoautotrophs (particularly cyanobacteria) identifies the need to resolve dietary targets at a microscopic scale. Here, we investigate parrotfish dietary targets by posing the following two questions: (1) are microscopic photoautotrophs the most consistent and dominant elements of the prey community, and (2) do the prey community and substratum taphonomy vary between parrotfish species? In order to identify and quantify dietary targets, five parrotfish species were followed until focused feeding was observed at Lizard Island on the Great Barrier Reef, Australia. Feeding sites were photographed in situ and extracted as substratum bite cores. Cores were analysed microscopically to identify and quantify all epilithic photoautotrophs. Endolithic photoautotrophs accessible to excavating parrotfish were also investigated by vacuum-embedding cores with epoxy resin followed by decalcification to expose endolith microborings. The dominant functional groups of epilithic biota on the cores were tufted cyanobacteria, turfing algae and crustose coralline algae (CCA). The only consistent feature across all cores was the high density of filamentous cyanobacteria, supporting the view that these parrotfishes target microphotoautotrophs. Macroalgae was absent or a minor component on cores, supporting the hypothesis that parrotfishes avoid larger algae. The microchlorophyte Ostreobium was the dominant photoautotrophic euendolith (true borer) in the cores of the excavating parrotfish Chlorurus microrhinos. Significant differences in CCA coverage, turf height and substrate taphonomy were found among the five parrotfish species, suggesting that interspecific resource partitioning is based on successional stage of feeding substrata.

Lake Baikal, one of the world’s largest and most biologically diverse lakes, has recently begun to experience uncharacteristic nuisance blooms of filamentous benthic algae. To contribute to understanding the causes of these blooms, we deployed nutrient-diffusing substrata (NDS) at 10 sites varying in shoreline land use in the southwestern portion of the lake. Our objectives were to assess the nature of nutrient limitation of benthic algae in Lake Baikal, the relationship between land use and limitation status, and the effect of enrichment on algal community composition. Algal biomass measured as chlorophyll a (Chl a) responded strongly to nutrient enrichment and showed serial limitation by N and P at all sites. Chl a levels were ∼2 and 4× higher on N− and N+P-amended NDS, respectively, than on unenriched controls. Periphyton biomass varied significantly among sites, but differences in periphyton biomass and nutrient limitation status were not related to shoreline land use. The taxonomic composition of periphyton varied significantly among landuse categories, nutrient treatments, and sites. The filamentous green alga Stigeoclonium tenue, which has been associated with recently observed nuisance blooms in Lake Baikal, tended to be most abundant on N− and N+P-amended NDS. The results of our study demonstrate strong nutrient limitation of the periphyton in Lake Baikal and highlight the potential value of improved nutrient controls for addressing benthic algal blooms in the lake.

The site is located on the corner of Jellicoe Lane and Tottenham Avenue in Melrose, Johannesburg North. The proposed development is to comprise a six-storey apartment block with a double basement parking garage.

Over the past decades numerous studies have reported declines in stony corals and, in many cases, phase shifts to fleshy macroalgae. However, long-term studies documenting changes in other benthic reef organisms are scarce. Here, we studied changes in cover of corals, algal turfs, benthic cyanobacterial mats, macroalgae, sponges and crustose coralline algae at four reef sites of the Caribbean islands of Curaçao and Bonaire over a time span of 40 yr. Permanent 9 m 2 quadrats at 10, 20, 30 and 40 m depth were photographed at 3- to 6-yr intervals from 1973 to 2013. The temporal and spatial dynamics in the six dominant benthic groups were assessed based on image point-analysis. Our results show consistent patterns of benthic community change with a decrease in the cover of calcifying organisms across all sites and depths from 32.6 (1973) to 9.2% (2013) for corals and from 6.4 to 1% for crustose coralline algae. Initially, coral cover was replaced by algal turfs increasing from 24.5 (1973) to 38% around the early 1990s. Fleshy macroalgae, still absent in 1973, also proliferated covering 12% of the substratum approximately 20 yr later. However, these new dominants largely declined in abundance from 2002 to 2013 (11 and 2%, respectively), marking the rise of benthic cyanobacterial mats. Cyanobacterial mats became the most dominant benthic component increasing from a mere 7.1 (2002) to 22.2% (2013). The observed increase was paralleled by a small but significant increase in sponge cover (0.5 to 2.3%). Strikingly, this pattern of degradation and phase change occurred over the reef slope down to mesophotic depths of 40 m. These findings suggest that reefs dominated by algae may be less stable than previously thought and that the next phase may be the dominance of slimy cyanobacterial mats with some sponges.

Microbial biofilms are biological structures composed of surface-attached microbial communities embedded in an extracellular polymeric matrix. In aquatic environments, the microbial colonization of submerged surfaces is a complex process involving several factors, related to both environmental conditions and to the physical-chemical nature of the substrates. Several studies have addressed this issue; however, more research is still needed on microbial biofilms in marine ecosystems. After a brief report on environmental drivers of biofilm formation, this study reviews current knowledge of microbial community attached to artificial substrates, as obtained by experiments performed on several material types deployed in temperate and extreme polar marine ecosystems. Depending on the substrate, different microbial communities were found, sometimes highlighting the occurrence of species-specificity. Future research challenges and concluding remarks are also considered. Emphasis is given to future perspectives in biofilm studies and their potential applications, related to biofouling prevention (such as cell-to-cell communication by quorum sensing or improved knowledge of drivers/signals affecting biological settlement) as well as to the potential use of microbial biofilms as sentinels of environmental changes and new candidates for bioremediation purposes.

Efforts to restore coral reefs usually involve transplanting asexually propagated fast-growing corals. However, this approach can lead to outplanted populations with low genotypic diversity, composed of taxa susceptible to stressors such as marine heatwaves. Sexual coral propagation leads to greater genotypic diversity, and using slow-growing, stress-tolerant taxa may provide a longer-term return on restoration efforts due to higher outplant survival. However, there have been no reports to date detailing the full cycle of rearing stress-tolerant, slow-growing corals from eggs until sexual maturity. Here, we sexually propagated and transplanted two massive slow-growing coral species to examine long-term success as part of reef restoration efforts. Coral spat were settled on artificial substrates and reared in nurseries for approximately two years, before being outplanted and monitored for survivorship and growth for a further four years. More than half of initially settled substrates supported a living coral following nursery rearing, and survivorship was also high following outplantation with yields declining by just 10 to 14% over four years. At 6-years post-fertilisation over 90% of outplanted corals were reproductively mature, demonstrating the feasibility of restoring populations of sexually mature massive corals in under a decade. Although use of slower growing, stress tolerant corals for reef restoration may provide a longer-term return on investment due to high post-transplantation survival rates, considerable time is required to achieve even modest gains in coral cover due to their relatively slow rates of growth. This highlights the need to use a mix of species with a range of life-history traits in reef restoration and to improve survivorship of susceptible fast-growing taxa that can generate rapid increases in coral cover.

We studied the effects of wildfires in southern California on stream algal communities and their responses to nutrient enrichment. The intensity of scouring floods, concentrations of nutrients during ensuing rains (4–13× increases depending on nutrient), and postflood sediment deposition were greater at sites in burned than in unburned basins (UN sites). Postfire storms reduced algal biomass >10× more at sites in burned than in unburned basins. After the fire and subsequent floods, algal biomass, particularly of Cladophora, was up to 5 (chlorophyll a) to 20 (macroalgal mass) times higher at sites in burned basins with burned riparian vegetation (BRB sites) than at sites in unburned basins (UN sites), but algal abundance at sites in burned basins with intact riparian vegetation (BRI sites) was as low as 10 to 30% of that recorded at UN sites. Two to 3 mo after the wet season, nutrient and algal levels were similar among sites in UN, BRI, and BRB basins. We used summer nutrient diffusing substrata (NDS) experiments where N, P, N+P, or neither were added and found that algal density, chl a, and chl a/algal unit increased by ∼1.5 to 4.5× with N additions at sites in BRB and UN basins but did not change at sites in BRI basins. In contrast, algal biovolume increased 2 to 9× with N additions at all sites and with P addition at sites in BRI basins. General depressions in chl a by 40 to 50% with P addition were related to decreased chl a/algal unit. Diatoms increased with N and N+P additions at sites in UN and BRI basins and with P addition at sites in BRI basins but declined with P or N+P additions at sites in BRB basins, with cyanobacteria and green algae generally showing the opposite pattern. Algal responses to nutrient augmentation across sites were related to fire effects on riparian canopy cover, temperature, and ambient nutrient concentrations. Fire effects on algal communities and nutrient limitation appeared to be mediated through fire effects on flood disturbance and light regimes.