The incidence and severity of extraordinary macroalgae blooms (green tides) are increasing. Here, climate change (ocean warming and acidification) impacts on life history and biochemical responses of ...a causative green tide species, Ulva rigida, were investigated under combinations of pH (7.95, 7.55, corresponding to lower and higher pCO2), temperature (14, 18°C) and nitrate availability (6 and 150μmolL−1). The higher temperature accelerated the onset and magnitude of gamete settlement. Any two factor combination promoted germination and accelerated growth in young plants. The higher temperature increased reproduction, which increased further in combination with elevated pCO2 or nitrate. Reproductive success was highest (64.4±5.1%) when the upper limits of all three variables were combined. Biochemically, more protein and lipid but less carbohydrate were synthesized under higher temperature and nitrate conditions. These results suggest that climate change may cause more severe green tides, particularly when eutrophication cannot be effectively controlled.
•Climate change effects shorten the life history of Ulva.•The time for gamete settlement and germination is reduced.•Growth of young and early-stage adults is stimulated, inducing more reproduction.•Climate change may intensify green tides where eutrophication is uncontrolled.
•Ocean warming and eutrophication increased total amino acids.•Ocean warming, acidification, and eutrophication increased total fatty acids.•Ocean warming enhanced swelling capacity and water holding ...capacity.•Ocean warming promoted oil holding capacity.
Ulva is increasingly viewed as a food source in the world. Here, Ulva rigida was cultured at two levels of temperature (14, 18 °C), pH (7.95, 7.55, corresponding to low and high pCO2), and nitrate conditions (6 μmol L−1, 150 μmol L−1), to investigate the effects of ocean warming, acidification, and eutrophication on food quality of Ulva species. High temperature increased the content of each amino acid. High nitrate increased the content of all amino acids except aspartic acid and cysteine. High temperature, pCO2, and nitrate also increased the content of most fatty acids. The combination of high temperature, pCO2, and nitrate increased the swelling capacity, water holding capacity, and oil holding capacity by 15.60%, 7.88%, and 16.32% respectively, compared to the control. It seems that the future ocean environment would enhance the production of amino acid and fatty acid as well as the functional properties of Ulva species.
Globally, ascidians are a significant contributor to benthic marine fouling communities, but have remained poorly studied in this context. In some cases, such as in shellfish and finfish aquaculture, ...ascidians are the most problematic of all fouling organisms. The disproportionate impact of ascidian fouling in some specific geographic locations has been related directly to anthropogenic translocation of these organisms around the globe. In the case of ascidians, therefore, the economic issue of biofouling and the ecological ramifications of invasion are inextricably linked. This mini-review briefly discusses the introduction of non-native ascidians to areas where they have subsequently proven to be a significant fouling pest. The elements of ascidian reproductive ecology that support their aggressive fouling character are discussed and the scant information pertaining to their adhesion and adhesives is presented. Finally, strategies for mitigating ascidian fouling are examined. It is suggested that sufficient working knowledge currently exists to support the inclusion of one or more common ascidian species as 'standard' test organisms used for evaluation of novel fouling-resistant surfaces.
Mapping the distribution of phylogenetically distinct bacteria in natural environments is of primary importance to an understanding of ecological dynamics. Here we present a quantitative PCR (qPCR) ...assay for the analysis of higher taxa composition in natural communities that advances previously available methods by allowing quantification of several taxa during the same qPCR run. Existing primers targeting the 16S rRNA gene specific for Firmicutes, Actinobacteria, Bacteroidetes and for the α and γ subdivisions of the Proteobacteria were improved by largely increasing the coverage of the taxon they target without diminishing their specificity. The qPCR assay was validated
in vitro testing artificial mixtures of 16S rRNA sequences and used to characterise the composition of natural communities developing in young marine biofilms. The possible contribution of the proposed technique in revealing ecological dynamics affecting higher bacterial taxa is discussed.
► Primers targeting higher bacterial taxa were designed. ► The use of these primers in qPCR improves previously available methods. ► The qPCR protocol presented was tested on artificial and natural communities. ► Marine biofilms showed reproducible changes in higher taxa composition.
Marine biofouling is a longstanding problem because of the constant challenges placed by various fouling species and increasingly restricted environmental regulations for antifouling coatings. Novel ...nonbiocidal strategies to control biofouling will necessitate a multifunctional approach to coating design. Here we show that slippery liquid-infused porous surfaces (SLIPSs) provide another possible strategy to obtaining promising antifouling coatings. Microporous butyl methacrylate–ethylene dimethacrylate (BMA–EDMA) surfaces are prepared via UV-initiated free-radical polymerization. Subsequent infusion of fluorocarbon lubricants (Krytox103, Krytox100, and Fluorinert FC-70) into the porous microtexture results in liquid-repellent slippery surfaces. To study the interaction with marine fouling organisms, settlement of zoospores of the alga Ulva linza and cypris larvae of the barnacle Balanus amphitrite is tested in laboratory assays. BMA–EDMA surfaces infused with Krytox103 and Krytox100 exhibit remarkable inhibition of settlement (attachment) of both spores and cyprids to a level comparable to that of a poly(ethylene glycol) (PEG)-terminated self-assembled monolayer. In addition, the adhesion strength of sporelings (young plants) of U. linza is reduced for BMA–EDMA surfaces infused with Krytox103 and Krytox100 compared to pristine (noninfused) BMA–EDMA and BMA–EDMA infused with Fluorinert FC-70. Immersion tests suggest a correlation between the stability of slippery coatings in artificial seawater and fouling resistance efficacy. The results indicate great potential for the application of this concept in fouling-resistant marine coatings.
For barnacle cypris larvae at the point of settlement, selection of an appropriate surface is critical. Since post-settlement relocation is usually impossible, barnacles have evolved finely tuned ...surface-sensing capabilities to identify suitable substrata, and a temporary adhesion system for extensive surface exploration. The pattern of exploratory behaviour appears complex and may last for several hours, imposing significant barriers to quantitative measurement. Here, we employ a novel tracking system that enables simultaneous analysis of the larval body movement of multiple individuals over their entire planktonic phase. For the first time, to our knowledge, we describe quantitatively the complete settlement process of cyprids as they explore and select surfaces for attachment. We confirm the ‘classic’ behaviours of wide searching, close searching and inspection that comprise a model originally proposed by Prof. Dennis Crisp FRS. Moreover, a short-term assay of cyprid body movement has identified inspection behaviour as the best indicator of propensity to settle, with more inspection-related movements occurring in conditions that also promote higher settlement. More than half a century after the model was first proposed by Crisp, there exists a precise method for quantifying cyprid settlement behaviour in wide-ranging investigations of barnacle ecology and applied studies of fouling management.
Over the last decade, approaches to the development of surfaces that perturb settlement and/or adhesion by barnacles have diversified substantially. Although, previously, coatings research focussed ...almost exclusively on biocidal technologies and low modulus, low surface-free-energy 'fouling-release' materials, novel strategies to control surface colonisation are now receiving significant attention. It is timely, therefore, to review the current 'state of knowledge' regarding fouling-resistant surface characteristics and their mechanisms of action against settling larvae of barnacles. The role of the barnacle in marine fouling is discussed here in the context of its life cycle and the behavioural ecology of its cypris larva. The temporary and permanent adhesion mechanisms of cyprids are covered in detail and an overview of adult barnacle adhesion is presented. Recent legislation has directed academic research firmly towards environmentally inert marine coatings, so the actions of traditional biocides on barnacles are not described here. Instead, the discussion is restricted to those surface modifications that interfere with settlement-site selection and adhesion of barnacle cypris larvae; specifically, textural engineering of surfaces, development of inert 'non-fouling' surfaces and the use of enzymes in antifouling.
Stalked and acorn barnacles (Cirripedia Thoracica) have a complex life cycle that includes a free-swimming nauplius larva, a cypris larva and a permanently attached sessile juvenile and adult ...barnacle. The barnacle cyprid is among the most highly specialized of marine invertebrate larvae and its settlement biology has been intensively studied. By contrast, surprisingly few papers have dealt with the critical series of metamorphic events from cementation of the cyprid to the substratum until the appearance of a suspension feeding juvenile. This metamorphosis is both ontogenetically complex and critical to the survival of the barnacle. Here we use video microscopy to present a timeline and description of morphological events from settled cyprid to juvenile barnacle in the model species Balanus amphitrite, representing an important step towards both a broader understanding of the settlement ecology of this species and a platform for studying the factors that control its metamorphosis. Metamorphosis in B. amphitrite involves a complex sequence of events: cementation, epidermis separation from the cypris cuticle, degeneration of cypris musculature, rotation of the thorax inside the mantle cavity, building of the juvenile musculature, contraction of antennular muscles, raising of the body, shedding of the cypris cuticle, shell plate and basis formation and, possibly, a further moult to become a suspension feeding barnacle. We compare these events with developmental information from other barnacle species and discuss them in the framework of barnacle settlement ecology.
Ulva species have been considered as ideal candidates for carbon capture, bioremediation and biofuel production. However, little is known regarding the effects of simultaneous ocean warming, ...acidification and eutrophication on these capacities. In this study, Ulva rigida was cultivated under two levels of: temperature (14 °C (LT) and 18 °C (HT)); pH (8.10 and 7.70) by controlling pCO2 (LC, HC respectively); and nutrients (low (LN) – 50 μm N and 2.5 μm P and high (HN) – 1000 μm N and 50 μm P) for 6 weeks. During the first week of cultivation, HT, HC and HN increased biomass by 38.1%, 17.1% and 20.8%, respectively, while the higher temperature led to negative growth in weeks 2, 4 and 6 due to reproductive events. By the end of the cultivation, biomass under HTHCHN was 130.4% higher than the control (LTLCLN), contributing to a higher carbon capture capacity. Although the thalli at HT released nutrients to seawater in weeks 2, 4 and 6, the HTHCHN treatment increased the overall nitrate uptake rate over the cultivation period by 489.0%. The HTHCHN treatment also had an increased biochemical methane potential and methane yield (47.3% and 254.6%, respectively). Our findings demonstrate that the capacities for carbon and nutrient capture, and biomethane production of U. rigida in the future ocean may be enhanced, providing important insight into the interactions between global change and seaweeds.
Our findings demonstrate that the capacities of carbon capture, bioremediation and biomethane production in U. rigida cultivated in the future ocean environment – increased pCO2, temperature, and nutrients – could be enhanced. This seems to be a negative feedback in response to the environmental changes caused by human activity and thus could alleviate global climate change. Our results provide important and much needed insight into the interactions between global change and ecologically and commercially important seaweeds.
Thoracian barnacles rely heavily upon their ability to adhere to surfaces and are environmentally and economically important as biofouling pests. Their adhesives have unique attributes that define ...them as targets for bio-inspired adhesive development. With the aid of multi-photon and broadband coherent anti-Stokes Raman scattering microscopies, we report that the larval adhesive of barnacle cyprids is a bi-phasic system containing lipids and phosphoproteins, working synergistically to maximize adhesion to diverse surfaces under hostile conditions. Lipids, secreted first, possibly displace water from the surface interface creating a conducive environment for introduction of phosphoproteins while simultaneously modulating the spreading of the protein phase and protecting the nascent adhesive plaque from bacterial biodegradation. The two distinct phases are contained within two different granules in the cyprid cement glands, implying far greater complexity than previously recognized. Knowledge of the lipidic contribution will hopefully inspire development of novel synthetic bioadhesives and environmentally benign antifouling coatings.
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