39 research outputs found

    A large aggregation of self-fragmenting mushroom corals in the Arabian/Persian Gulf

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    [No abstract available]The Arabian/Persian Gulf is a relatively shallow, semi‐enclosed sea at high tropical latitudes, surrounded by desert land with limited water exchange, high salinities, and extreme annual fluctuations of surface temperatures (Sheppard et al. 1992). These conditions restrict the Gulf's marine biodiversity, as demonstrated by the mushroom coral family Fungiidae (Scleractinia). In the Gulf, this family has only been known to be represented by the free‐living (unattached) species, Cycloseris curvata (Hoeksema, 1989), which is considered uncommon (Riegl et al. 2012), whereas this coral family consists of 52 described species in the entire tropical Indo‐Pacific, 40 of which are unattached (Benzoni et al. 2012).This publication was made possible by NPRP awards [NPRP 7-1129-1-201 and NPRP 8-952-1-186] from the Qatar National Research Fund (a member of the Qatar Foundation) and by the Qatar Museums Authority through the project �Research on Qatar�s geological history and present-day biodiversity� granted to Naturalis Biodiversity Center. The statements made herein are solely the responsibility of the authors. The whip coral species (Fig. 1) was identified by L. P. van Ofwegen. We thank the reviewer and editor for their constructive comments.Scopu

    Evaluation of Satellite Retrievals of Chlorophyll-a in the Arabian Gulf

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    The Arabian Gulf is a highly turbid, shallow sedimentary basin whose coastal areas have been classified as optically complex Case II waters (where ocean colour sensors have been proved to be unreliable). Yet, there is no such study assessing the performance and quality of satellite ocean-colour datasets in relation to ground truth data in the Gulf. Here, using a unique set of in situ Chlorophyll-a measurements (Chl-a; an index of phytoplankton biomass), collected from 24 locations in four transects in the central Gulf over six recent research cruises (2015–2016), we evaluated the performance of VIIRS and other merged satellite datasets, for the first time in the region. A highly significant relationship was found (r = 0.795, p < 0.001), though a clear overestimation in satellite-derived Chl-a concentrations is evident. Regardless of this constant overestimation, the remotely sensed Chl-a observations illustrated adequately the seasonal cycles. Due to the optically complex environment, the first optical depth was calculated to be on average 6–10 m depth, and thus the satellite signal is not capturing the deep chlorophyll maximum (DCM at ~25 m). Overall, the ocean colour sensors’ performance was comparable to other Case II waters in other regions, supporting the use of satellite ocean colour in the Gulf. Yet, the development of a regional-tuned algorithm is needed to account for the unique environmental conditions of the Gulf, and ultimately provide a better estimation of surface Chl-a in the region

    Bioprospecting autochthonous marine microalgae strain from the Arabian Gulf Seawater, Kuwait for biofuel feedstocks

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    Bioprospecting programs are the key to increasing the current portfolio of indigenous microalgal strains accessible for different applications in microalgal biotechnology. In this work, nine fast-growing microalgal strains isolated from Kuwait's Arabian/Persian Gulf coastal waters were evaluated for their potential as biofuel feedstocks. 18S rRNA gene sequencing showed that the strains belong to five different genera: Chlorella, Nannochloris, Scenedesmus, Tetraselmis, and Nannochloropsis. In terms of the total lipid content, in comparison to the other strains, Tetraselmis sp. KUBS13G and Tetraselmis sp. KUBS16G displayed higher lipid contents of 29.56% dry weight (DW) and 26.13% DW, respectively, dominated by palmitic and oleic acids. Fuel properties calculated from the fatty acid methyl esters (FAMES) by empirical equations were compared with EN14214 (European) and ASTM D6751--02 (American) biodiesel standards. Multicriteria decision analysis (MCDA) methods, such as the Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GALA), were used to select suitable microalgae for biofuel feedstock based on their biodiesel fuel properties. Overall, the results suggested that the indigenous microalgal strain Tetraselmis, particularly Tetraselmis sp. KUBS37G, and Scenedesmus sp. KUB Sl7R are the most suitable strains for biofuel feedstock owing to their improved fuel properties, such as density (rho) (0.88 g cm-3), low kinematic viscosity (3.1 mm2 s-1), high cetane number (54 and 56, respectively), high oxidation stability (14.6 hr and 14.8 hr), and cold filter plugging point (1.0 degrees C and -6.1 degrees C).info:eu-repo/semantics/publishedVersio

    International Centre for Coastal Ecohydrology: applying the ecohydrology approach for the sustainable functioning of coastal ecosystems

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    Coastal areas are among the most sensitive and productive ecosystems around the world, providing for the subsistence of large numbers of people, particularly in developing countries. Human pressure on coastal areas has dramatically increased during the last decades and climate changes will pose new threats to these areas, as expected from sea-level rise and the decrease in freshwater discharges from rivers (Chicharo et al., 2009). The International Centre for Coastal Ecohydrology (ICCE) a newly approved centre under the auspices of UNESCO, in October 2009, is located in the Algarve region (south Portugal). The centre acts as a facilitator and synergetic structure by providing the articulation of different scientific and institutional stakeholders at national and international levels. ICCE aims are to contribute scientific knowledge, capacity-building, educational and dissemination activities to support, design and implement adaptation and mitigation strategies and policies for coastal zones, including the impacts of climate change, addressing the goals of the Strategic Plan of the 7th Phase of UNESCO-IHP, the Millennium Development Goals (UN-MDGs) and the key themes for the United Nations Decade of Education for Sustainable Development (UN-DESD), particularly in African and Mediterranean regions.info:eu-repo/semantics/publishedVersio

    Born small, die young: Intrinsic, size-selective mortality in marine larval fish

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    Mortality during the early stages is a major cause of the natural variations in the size and recruitment strength of marine fish populations. In this study, the relation between the size-at-hatch and early survival was assessed using laboratory experiments and on field-caught larvae of the European sardine (Sardina pilchardus). Larval size-at-hatch was not related to the egg size but was significantly, positively related to the diameter of the otolith-at-hatch. Otolith diameter-at-hatch was also significantly correlated with survival-at-age in fed and unfed larvae in the laboratory. For sardine larvae collected in the Bay of Biscay during the spring of 2008, otolith radius-at-hatch was also significantly related to viability. Larval mortality has frequently been related to adverse environmental conditions and intrinsic factors affecting feeding ability and vulnerability to predators. Our study offers evidence indicating that a significant portion of fish mortality occurs during the endogenous (yolk) and mixed (yolk /prey) feeding period in the absence of predators, revealing that marine fish with high fecundity, such as small pelagics, can spawn a relatively large amount of eggs resulting in small larvae with no chances to survive. Our findings help to better understand the mass mortalities occurring at early stages of marine fish.info:eu-repo/semantics/publishedVersio

    Thermodynamics, isotherms, and mechanisms studies of lithium recovery from seawater desalination reverse osmosis brine using roasted and ferrocyanide modified date pits

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    In this study, the adsorption isotherms and thermodynamic studies of lithium ions from seawater reverse osmosis (SWRO) desalination brine were investigated. Three adsorbents were utilized namely, roasted date pits (RDP), potassium copper, and nickel hexacyanoferrate-date pits (RDP-FC-Cu and RDP-FC-Ni). The prepared adsorbents showed enhanced morphological and chemical structures such as high porosity, carbonaceous composition, larger pore and volume sizes, smaller particle sizes as well as the presence of unique functional groups on their surface. The adsorption of lithium ions onto the three adsorbents was enhanced with an increase in solution temperature and initial lithium concentration. The temperature that showed the highest adsorption of lithium ions onto the three adsorbents was 45 °C. The adsorption of lithium ions onto the three adsorbents was the highest at an initial lithium concentration of 100 mg/L. The three adsorbents achieved an adsorption capacity of around 99 mg/g at the optimum temperature and initial concentration. On the other hand, RDP-FC-Cu achieved the highest adsorption capacities for lithium ions at all the studied initial concentrations. The thermodynamic study showed that the adsorption process of lithium ions onto the adsorbents is endothermic, spontaneous, and favorable at all the studied temperatures (25 °C, 35 °C, and 45 °C). Moreover, the adsorption of lithium ions onto the three adsorbents followed the Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin adsorption isotherm models differently at each studied temperature. For RDP, the adsorption process followed the Freundlich adsorption isotherm model at 25 °C, while it was more fitted to the Langmuir isotherm model at 45 °C and all models at 35 °C. The adsorption of lithium ions onto RDP-FC-Cu followed Langmuir adsorption isotherm model at 25 °C and 35 °C, while it fitted all models at 45 °C. On the other hand, Langmuir and Dubinin–Radushkevich isotherm models were best fit for the adsorption of lithium ions onto RDP-FC-Ni at 25 °C and 35 °C. The desorption study presented 99% desorption percentages of lithium ions from all the adsorbents, which showed the great regeneration potential of the adsorbents. Furthermore, the selectivity study showed that RDP-FC-Cu achieved 99.9% adsorption removal of lithium ions from the SWRO brine while RDP-FC-Ni and RDP achieved 99.8% and 99.3% adsorption removals, respectively. Finally, the cost analysis revealed that the total cost for the preparation of the adsorbent was 29.81 USD.Scopu

    Consequences of marine barriers for genetic diversity of the coral-specialist yellowbar angelfish from the Northwestern Indian Ocean

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    Ocean circulation, geological history, geographic distance, and seascape heterogeneity play an important role in phylogeography of coral‐dependent fishes. Here, we investigate potential genetic population structure within the yellowbar angelfish (Pomacanthus maculosus) across the Northwestern Indian Ocean (NIO). We then discuss our results with respect to the above abiotic features in order to understand the contemporary distribution of genetic diversity of the species. To do so, restriction site‐associated DNA sequencing (RAD‐seq) was utilized to carry out population genetic analyses on P. maculosus sampled throughout the species’ distributional range. First, genetic data were correlated to geographic and environmental distances, and tested for isolation‐by‐distance and isolation‐by‐environment, respectively, by applying the Mantel test. Secondly, we used distance‐based and model‐based methods for clustering genetic data. Our results suggest the presence of two putative barriers to dispersal; one off the southern coast of the Arabian Peninsula and the other off northern Somalia, which together create three genetic subdivisions of P. maculosus within the NIO. Around the Arabian Peninsula, one genetic cluster was associated with the Red Sea and the adjacent Gulf of Aden in the west, and another cluster was associated with the Arabian Gulf and the Sea of Oman in the east. Individuals sampled in Kenya represented a third genetic cluster. The geographic locations of genetic discontinuities observed between genetic subdivisions coincide with the presence of substantial upwelling systems, as well as habitat discontinuity. Our findings shed light on the origin and maintenance of genetic patterns in a common coral reef fish inhabiting the NIO, and reinforce the hypothesis that the evolution of marine fish species in this region has likely been shaped by multiple vicariance events.This work was conducted within the framework of the NPRP project ‘Connectivity, diversity and genetic between offshore natural coral reefs and oil platforms – NPRP No. 7‐1129‐1‐201’, funded by the Qatar National Research Fund (a member of The Qatar Foundation). The statements made herein are solely the responsibility of the authors. F.T. is supported by a CNPq/Brazil fellowship through the program Science without Borders (Proc. 232875/2014‐6). We are also grateful to Filipe Vieira (University of Copenhagen) for his advice on population genetic analyses

    Mychonastes homosphaera (Chlorophyceae): A promising feedstock for high quality feed production in the arid environment

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    Rapid development and drastic population increase in Qatar have led to increasing awareness about food security. Microalgae are considered one of the most promising feedstocks owing to their ability to produce nutrients, including lipids, carbohydrates, and proteins, in addition to antioxidants, vitamins, and minerals. In this study, 30 isolates of local freshwater microalgae were screened first based on their growth rate to select the most suitable strains for feed production. Based on the normality test, 15 fast-growing microalgae isolates were selected and subjected to further investigation of their metabolites content. The hierarchical Cluster Analysis conducted on lipids, proteins and carbohydrates contents subdivided these strains selected into 4 clusters, among them, the cluster one was grouping three Chlorella and two Mychonastes isolates with high nutritional values due to their high amounts of lipid and protein. The survey of metabolite production was performed every three days during growth in a volume of 3 L. We observed that the maximum amount of proteins and lipids was produced at day 6 and 14, respectively. The assessment of the Trolox equivalent antioxidant capacity of the top 5 strains proved that Mychonastes homosphaera isolate QUCCCM70 showed the highest antioxidant capacity. Moreover, results revealed the presence of essential amino acids and omega3 fatty acids. The screening evidenced a Mychonastes homosphaera strain QUCCCM70 with high nutritional value that can be considered as a promising alternative to produce a well-balanced animal feed supplement for a high quality of poultry and livestock products.This publication was made possible by the NPRP grant # [NPRP8-1087-1-207] from the Qatar National Research Fund (a member of Qatar Foundation). The findings herein reflect the work, and are solely the responsability of the authors. Special thanks go to Anna Aguilar and Pedram Shahbazi and Maaroof Eroth for the technical support

    Diet and feeding intensity of sardine Sardina pilchardus: correlation with satellite-derived chlorophyll data

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    Spatio-temporal variability of the diet of sardine Sardina pilchardus off Portugal was examined through analysis of the stomach contents of fish collected every 14 d from the west and south of Portugal during 2003/2004. Dietary composition of the modal sardine length class was assessed by determining the frequency of occurrence and carbon content of identified prey, and these 2 parameters were combined to estimate a modified index of relative importance of prey (mIRI). The most important prey for sardines were zooplankton, comprising crustacean eggs, copepods, decapods, cirripedes and fish eggs, dinoflagellates and diatoms (particularly the toxin-producer\ud genus Pseudo-nitzschia), which together accounted for >90% of the estimated dietary carbon. Dietary seasonality was similar for both areas, except that the contribution of phytoplankton was higher for fish from the west Portuguese coast, where upwelling events are stronger and recurrent during spring and summer months. The predominance of prey <750 μm in sardine diet suggests that filter feeding is the dominant feeding mode used in the wild. Feeding intensity was similar for both sexes and for fish of different length classes and was higher on the west coast than in the south, which is probably related to the higher productivity of the west coast. Although there was high inter-annual variability in feeding intensity, this parameter was highest for both areas during spring and winter months. Temporal variability in satellite-derived chlorophyll a matched the temporal variability in the dietary contribution by phytoplankton and of sardine feeding intensity, suggesting further investigation of the potential use of satellite-derived chlorophyll a data as a proxy for sardine feeding intensity

    Marine climate change risks to biodiversity and society in the ROPME Sea Area

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    The subtropical ROPME Sea Area (RSA), comprising the Gulf, the Gulf of Oman and the northern Arabian Sea, is a heavily exploited sea region that experiences extreme environmental conditions, and for which climate change is expected to further impact marine ecosystems and coastal communities, sectors and industries. Climate change risk assessments provide a valuable tool to inform decision-making and adaptation planning through identifying and prioritising climate risks and/or opportunities. Using the first UK Climate Change Risk Assessment as an example, a marine climate change risk assessment was undertaken for the marine and coastal environment of the RSA for the first time. Through an extensive literature review and a workshop involving regional experts, marine and coastal climate change risks were identified, scored and prioritised. A total of 45 risks were identified, which spanned two key themes: ‘Risks to Biodiversity’ and ‘Risks to Economy and Society’. Of these, 13 were categorised as ‘severe’, including degradation of coral reefs and their associated ecological assemblages, shifts in the distribution of wild-capture fisheries resources, changes to phytoplankton primary productivity, impacts on coastal communities, threats to infrastructure and industries, and impacts on operations and safety in maritime transport. The diversity of risks identified and their transboundary nature highlight that climate change adaptation responses will require coordinated action and cooperation at multiple scales across the RSA. This risk assessment provides a crucial baseline for a largely overlooked geographic area, that can be used to underpin future decision-making and adaptation planning on climate change, and serve as a ‘blueprint’ for similar assessments for other regional shared seas
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