• The geochemistry and oxidation state of podiform chromitites from the mantle section of the Oman ophiolite: A review

      Rollinson, Hugh; Adetunji, Jacob; University of Derby (Elsevier, 2015-02)
      Data are presented for mantle podiform chromitites from eight localities over 350 km strike length of the Oman ophiolite. Chromitite compositions form a continuum from cr# = 0.501 to 0.769, although this conflates a number of different magmatic ‘events’. The Oman mantle chromitites record a wide range of Fe3 +/ΣFe ratios (as determined by Mössbauer spectroscopy) extending from low values (close to those of MORB) to values higher than currently found in arc magmas and calculated oxygen fugacities for the chromites are about 1.8 log units above the QFM buffer, higher than found in the MORB source. Calculated TiO2 and Al2O3 contents for the parental melts to the Oman chromitites show that they had low TiO2 contents (0.23–0.96 wt.%) but a range of Al2O3 contents (11.8–15.8 wt.%). The variable Al2O3 content implies a range of parental magma compositions, probably formed at different temperatures, and the range of TiO2 compositions indicates that some melts were modified by reaction during their transit through the mantle. The range of compositions observed is not consistent with either a MORB or Arc source but is thought to reflect a range of melts derived from a compositionally evolving source during subduction initiation in a forearc environment
    • Geographical variation in the response to nitrogen deposition in Arabidopsis lyrata petraea.

      Vergeer, Philippine; van den Berg, Leon L. J.; Bulling, Mark T.; Ashmore, Mike R.; Kunin, William E.; University of Leeds, Institute of Integrative and Comparative Biology (2008)
      The adaptive responses to atmospheric nitrogen deposition for different European accessions of Arabidopsis lyrata petraea were analysed using populations along a strong atmospheric N-deposition gradient. Plants were exposed to three N-deposition rates, reflecting the rates at the different locations, in a full factorial design. Differences between accessions in the response to N were found for important phenological and physiological response variables. For example, plants from low-deposition areas had higher nitrogen-use efficiencies (NUE) and C : N ratios than plants from areas high in N deposition when grown at low N-deposition rates. The NUE decreased in all accessions at higher experimental deposition rates. However, plants from high-deposition areas showed a limited capacity to increase their NUE at lower experimental deposition rates. Plants from low-deposition areas had faster growth rates, higher leaf turnover rates and shorter times to flowering, and showed a greater increase in growth rate in response to N deposition than those from high-deposition areas. Indications for adaptation to N deposition were found, and results suggest that adaptation of plants from areas high in N deposition to increased N deposition has resulted in the loss of plasticity.
    • Geographically conserved rates of background mortality among common reef-building corals in Lhaviyani Atoll, Maldives, versus northern Great Barrier Reef, Australia

      Pisapia, Chiara; Sweet, Michael J.; Sweatman, Hugh; Pratchett, Morgan; University of Derby (Springer Berlin Heidelberg, 2015-07-14)
      Even in the absence of major disturbances (e.g., cyclones and bleaching), corals are consistently subject to high levels of background mortality, which under-mines individual fitness and resilience of coral colonies. Most studies of coral mortality however only focus on catastrophic mortality associated with major acute disturbance events, neglecting to consider background levels of chronic mortality that have a significant influence on population structure and turnover. If, for example, there are geo-graphic differences in the prevalence of injuries and rates of background mortality, coral communities may vary in their susceptibility to acute large-scale disturbances and environmental change. This study quantified the prevalence and severity of partial mortality for four dominant and widespread coral taxa (massive Porites, encrusting Montipora, Acropora hyacinthus,and branching Pocillopora) at Lhaviyani Atoll, Maldives, and on the northern Great Barrier Reef, Australia. The prevalence and severity of sublethal injuries varied greatly among taxa, but was generally similar between locations; on the Great Barrier Reef, 99.4 % Porites colonies, 66 % of A. hyacinthus, and 64 % of Pocillopora had conspicuous injuries, compared to 92.4 % of Porites, 47.5 % of A. hyacinthus, and 44 % of Pocillopora colonies in Lhaviyani Atoll. These results suggest that background rates of mortality and injury, and associated resilience of coral populations and communities to large-scale disturbances, are conserved at large geo-graphic scales, though adjacent colonies can have markedly different injury regimes, likely to lead to strong intraspecific variation in colony fitness and resilience.
    • Geology of Caphouse Colliery, Wakefield, Yorkshire, UK

      Davies-Vollum, K. Siân; Guion, Paul. D.; Knight, John. A.; Smith, Andrew; University of Derby (Geological Society of London, 2016-09-28)
      The National Coal Mining Museum in West Yorkshire affords a rare opportunity for the public to visit a former colliery (Caphouse) and experience at first hand the geology of a mine. The geology at the museum can be seen via the public tour, limited surface outcrop and an inclined ventilation drift, which provides the best geological exposure and information. The strata encountered at the site are c. 100 m thick and are of latest Langsettian (Pennsylvanian) age. The ventilation drift intersects several coal seams (Flockton Thick, Flockton Thin, Old Hards, Green Lane and New Hards) and their associated roof rocks and seatearths. In addition to exposures of bedrock, recent mineral precipitates of calcium carbonates, manganese carbonates and oxides, and iron oxyhydroxides can be observed along the drift, and there is a surface exposure of Flockton Thick Coal and overlying roof strata. The coals and interbedded strata were deposited in the Pennine Basin in a fluvio-lacustrine setting in an embayment distant from the open ocean with limited marine influence. A lacustrine origin for mudstone roof rocks of several of the seams is supported by the incidence of non-marine bivalves and fossilized fish remains whilst the upper part of the Flockton Thick Coal consists of subaqueously deposited cannel coal. The mudstones overlying the Flockton Thick containing abundant non-marine bivalves are of great lateral extent, indicating a basin-wide rise of base level following coal deposition that may be compared with a non-marine flooding surface.
    • Glacial history of Mt Chelmos, Peloponnesus, Greece

      Pope, R. J.; Hughes, P. D.; Skourtsos, E.; University of Derby; University of Manchester; University of Athens (Geological Society of London, 2015-11-11)
      Mount Chelmos in the Peloponnesus was glaciated by a plateau ice field during the most extensive Pleistocene glaciation. Valley glaciers radiated out from an ice field centred over the central plateau of the massif. The largest glaciations are likely to be Middle Pleistocene in age. Smaller valley and cirque glaciers formed later and boulders on the moraines of these glacial phases have been dated using 36 Cl terrestrial cosmogenic nuclide exposure dating. These ages indicate a Late Pleistocene age with glacier advance/stabilisation at 40-30 ka, glacier retreat at 23-21 ka and advance/stabilisation at 13-10 ka. This indicates that the glacier maximum of the last cold stage occurred during Marine Isotope Stage (MIS) 3, several thousand years before the global Last Glacial Maximum (LGM; MIS 2) . The last phase of moraine building occurred at the end of the Pleistocene, possibly during the Younger Dryas.
    • Global Invasive Potential of 10 Parasitic Witchweeds and Related Orobanchaceae

      Mohamed, Kamal I.; Papes, Monica; Williams, Richard; Benz, Brett W.; Peterson, A. Townsend; Department of Biology, Oswego State University of New York, Oswego, NY 13126 USA; Natural History Museum and Biodiversity Research Center, The University of Kansas, Lawrence, KS 66045 USA. (Royal Swedish Academy of Sciences, 2006-09-01)
      The plant family Orobanchaceae includes many parasitic weeds that are also impressive invaders and aggressive crop pests with several specialized features (e.g. microscopic seeds, parasitic habits). Although they have provoked several large-scale eradication and control efforts, no global evaluation of their invasive potential is as yet available. We use tools from ecological niche modeling in combination with occurrence records from herbarium specimens to evaluate the global invasive potential of each of 10 species in this assemblage, representing several of the worst global invaders. The invasive potential of these species is considerable, with all tropical and subtropical countries, and most temperate countries, vulnerable to invasions by one or more of them.
    • Global patterns of bioturbation intensity and mixed depth of marine soft sediments

      Teal, L. R.; Bulling, Mark T.; Parker, E. R.; Solan, Martin (2013-06-11)
      ABSTRACT: The importance of bioturbation in mediating biogeochemical processes in the upper centimetres of oceanic sediments provides a compelling reason for wanting to quantify in situ rates of bioturbation. Whilst several approaches can be used for estimating the rate and extent of bioturba- tion, most often it is characterized by calculating an intensity coefficient (D b ) and/or a mixed layer depth (L). Using measures of D b (n = 447) and L (n = 784) collated largely from peer-reviewed litera- ture, we have assembled a global database and examined patterns of both L and D b . At the broadest level, this database reveals that there are considerable gaps in our knowledge of bioturbation for all major oceans other than the North Atlantic, and almost universally for the deep ocean. Similarly, there is an appreciable bias towards observations in the Northern Hemisphere, particularly along the coastal regions of North America and Europe. For the assembled dataset, we find large discrepancies in estimations of L and D b that reflect differences in boundary conditions and reaction properties of the methods used. Tracers with longer half-lives tend to give lower D b estimates and deeper mixing depths than tracers with shorter half-lives. Estimates of L based on sediment profile imaging are significantly lower than estimates based on tracer methods. Estimations of L, but not D b , differ between biogeographical realms at the global level and, at least for the Temperate Northern Atlantic realm, also at the regional level. There are significant effects of season irrespective of location, with higher activities (D b ) observed during summer and deeper mixing depths (L) observed during autumn. Our evaluation demonstrates that we have reasonable estimates of bioturbation for only a limited set of conditions and regions of the world. For these data, and based on a conservative global mean (±SD) L of 5.75 ± 5.67 cm (n = 791), we calculate the global volume of bioturbated sediment to be >20 700 km 3 . Whilst it is clear that the role of benthic invertebrates in mediating global ecosystem processes is substantial, the level of uncertainty at the regional level is unacceptably high for much of the globe.
    • A global synthesis of plant extinction rates in urban areas.

      Hahs, Amy K.; McDonnell, Mark J.; McCarthy, Michael A.; Vesk, Peter A.; Corlett, Richard T.; Norton, Briony, A.; Clemants, Steven E.; Duncan, Richard P.; Thompson, Ken; Schwartz, Mark W.; et al. (Wiley, 2009-10-13)
      Plant extinctions from urban areas are a growing threat to biodiversity worldwide. To minimize this threat, it is critical to understand what factors are influencing plant extinction rates. We compiled plant extinction rate data for 22 cities around the world. Two‐thirds of the variation in plant extinction rates was explained by a combination of the city’s historical development and the current proportion of native vegetation, with the former explaining the greatest variability. As a single variable, the amount of native vegetation remaining also influenced extinction rates, particularly in cities > 200 years old. Our study demonstrates that the legacies of landscape transformations by agrarian and urban development last for hundreds of years, and modern cities potentially carry a large extinction debt. This finding highlights the importance of preserving native vegetation in urban areas and the need for mitigation to minimize potential plant extinctions in the future.
    • Green roof and ground-level invertebrate communities are similar and are driven by building height and landscape context

      Dromgold, Jacinda R; Threlfall, Caragh G; Norton, Briony, A.; Williams, Nicholas S G; University of Melbourne, Melbourne, Australia; University of Derby (Oxford University Press (OUP), 2020-01-30)
      Green roofs are increasingly promoted for urban biodiversity conservation, but the value of these novel habitats is uncertain. We aimed to test two hypotheses: (i) green roofs can support comparable invertebrate family and order richness, composition and abundances to ground-level habitats and (ii) green roofs planted with native species from local habitats will support a richer invertebrate community at family and order level than other green roofs. We sampled the invertebrate community on green roofs dominated by native grassland or introduced succulent species in Melbourne, Australia, and compared these to the invertebrate community in ground-level sites close by, and sites with similar vegetation types. The only significant differences between the invertebrate communities sampled on green roofs and ground-level habitats were total abundance and fly family richness, which were higher in ground-level habitats. Second hypothesis was not supported as invertebrate communities on green roofs supporting a local vegetation community and those planted with introduced Sedum and other succulents were not detectably different at family level. The per cent cover of green space surrounding each site was consistently important in predicting the richness and abundance of the invertebrate families we focussed on, while roof height, site age and size were influential for some taxa. Our results suggest that invertebrate communities of green roofs in Melbourne are driven largely by their surrounding environment and consequently the effectiveness of green roofs as invertebrate habitat is highly dependent on location and their horizontal and vertical connection to other habitats.
    • Grooming relationships between breeding females and adult group members in cooperatively breeding moustached tamarins (Saguinus mystax)

      Löttker, Petra; Huck, Maren; Zinner, Dietmar P.; Heymann, Eckhard W.; Department of Behavioral Ecology and Sociobiology, German Primate Centre; Department of Cognitive Ethology, German Primate Centre, Germany (2007)
      Grooming is the most common form of affiliative behavior in primates that apart from hygienic and hedonistic benefits offers important social benefits for the performing individuals. This study examined grooming behavior in a cooperatively breeding primate species, characterized by single female breeding per group, polyandrous matings, dizygotic twinning, delayed offspring dispersal, and intensive helping behavior. In this system, breeding females profit from the presence of helpers but also helpers profit from staying in a group and assisting in infant care due to the accumulation of direct and indirect fitness benefits. We examined grooming relationships of breeding females with three classes of partners (breeding males, potentially breeding males, (sub)adult non-breeding offspring) during three reproductive phases (post-partum ovarian inactivity, ovarian activity, pregnancy) in two groups of wild moustached tamarins (Saguinus mystax). We investigated whether grooming can be used to regulate group size by either ‘‘pay-for-help’’ or ‘‘pay-to-stay’’ mechanisms. Grooming of breeding females with breeding males and nonbreeding offspring was more intense and more balanced than with potentially breeding males, and most grooming occurred during the breeding females’ pregnancies. Grooming was skewed toward more investment by the breeding females with breeding males during the phases of ovarian activity, and with potentially breeding males during pregnancies. Our results suggest that grooming might be a mechanism used by female moustached tamarins to induce mate association with the breeding male, and to induce certain individuals to stay in the group and help with infant care.
    • Ground-control networks for image based surface reconstruction: An investigation of optimum survey designs using UAV derived imagery and structure-from-motion photogrammetry

      Tonkin, Toby N.; Midgley, Nicholas G.; University of Derby; Nottingham Trent University (Multidisciplinary Digital Publishing Institute (MDPI), 2016-09-21)
      The use of small UAVs (Unmanned Aerial Vehicles) and Structure-from-Motion (SfM) with Multi-View Stereopsis (MVS) for acquiring survey datasets is now commonplace, however, aspects of the SfM-MVS workflow require further validation. This work aims to provide guidance for scientists seeking to adopt this aerial survey method by investigating aerial survey data quality in relation to the application of ground control points (GCPs) at a site of undulating topography (Ennerdale, Lake District, UK). Sixteen digital surface models (DSMs) were produced from a UAV survey using a varying number of GCPs (3-101). These DSMs were compared to 530 dGPS spot heights to calculate vertical error. All DSMs produced reasonable surface reconstructions (vertical root-mean-square-error (RMSE) of <0.2 m), however, an improvement in DSM quality was found where four or more GCPs (up to 101 GCPs) were applied, with errors falling to within the suggested point quality range of the survey equipment used for GCP acquisition (e.g., vertical RMSE of <0.09 m). The influence of a poor GCP distribution was also investigated by producing a DSM using an evenly distributed network of GCPs, and comparing it to a DSM produced using a clustered network of GCPs. The results accord with existing findings, where vertical error was found to increase with distance from the GCP cluster. Specifically vertical error and distance to the nearest GCP followed a strong polynomial trend (R2 = 0.792). These findings contribute to our understanding of the sources of error when conducting a UAV-SfM survey and provide guidance on the collection of GCPs. Evidence-driven UAV-SfM survey designs are essential for practitioners seeking reproducible, high quality topographic datasets for detecting surface change.
    • Growth and development in wild Owl Monkeys (Aotus azarai) of Argentina

      Huck, Maren; Rotundo, Marcelo; Fernández-Duque, Eduardo; University of Pennsylvania; Fundacion ECO; Centro de Ecologia Aplicada del Litoral, CONICET (2011)
      Life history predicts that in sexually dimorphic species in which males are the larger sex, males should reach sexual maturity later than females (or vice versa if females are the larger sex). The corresponding prediction that in sexually monomorphic species maturational rates will differ little between the sexes has rarely been tested. We report here sex differences in growth and development to adulthood for 70 female and 69 male wild owl monkeys (Aotus azarai). In addition, using evidence from natal dispersal and first reproduction (mean: 74 mo) for 7 individuals of known age, we assigned ages to categories: infant, 0–6 mo; juvenile, 6.1–24 mo; subadult, 24.1–48 mo; adult >48 mo. We compared von Bertalanffy growth curves and growth rates derived from linear piecewise regressions for juvenile and subadult females and males. Growth rates did not differ between the sexes, although juvenile females were slightly longer than males. Females reached maximum maxillary canine height at ca. 2 yr, about a year earlier than males, and females’ maxillary canines were shorter than males’. Thus apart from canine eruption and possibly crown–rump length, the development of Azara’s owl monkeys conforms to the prediction by life history that in monomorphic species the sexes should develop at similar paces.
    • Growth rate and extinction amongst Plio-Pleistocene bivalve molluscs of the western and eastern North Atlantic region

      Clarke, Abigail; Featherstone, Aaron; Heywood, Daniel; Thornton, Luke; Richardson, Kathryn; Johnson, Andrew L. A.; University of Derby (2017-07-03)
    • Growth rate, extinction and survival amongst late Cenozoic bivalves of the North Atlantic

      Johnson, Andrew L. A.; Harper, Elizabeth M.; Clarke, Abigail; Featherstone, Aaron C.; Heywood, Daniel J.; Richardson, Kathryn E.; Spink, Jack O.; Thornton, Luke A.H.; University of Derby (Taylor & Francis, 2019-09-12)
      Late Cenozoic bivalve extinction in the North Atlantic and adjacent areas has been attributed to environmental change (declines in temperature and primary production). Within scallops and oysters—bivalve groups with a high growth rate—certain taxa which grew exceptionally fast became extinct, while others which grew slower survived. The taxa which grew exceptionally fast would have obtained protection from predators thereby, so their extinction may have been due to the detrimental effect of environmental change on growth rate and ability to avoid predation, rather than environmental change per se. We investigated some glycymeridid and carditid bivalves—groups with a much lower growth rate than scallops and oysters—to see whether extinct forms from the late Cenozoic of the North Atlantic grew faster than extant forms, and hence whether their extinction may also have been mediated by increased mortality due to predation. Growth rate was determined from the cumulative width of annual increments in the hinge area; measurements were scaled up to overall shell size for the purposes of comparison with data from living species. Growth of the extinct glycymeridid Glycymeris subovata was at about the same rate as the slowest-growing living glycymeridid and much slower than in late Cenozoic samples of extant G. americana, in which growth was at about the same rate as the fastest-growing living glycymeridid. Growth of extinct G. obovata was also slower than G. americana, and that of the extinct carditid Cardites squamulosa ampla similarly slow (evidently slower than in the one living carditid species for which data are available). These findings indicate that within bivalve groups whose growth is much slower than scallops and oysters, extinction or survival of taxa through the late Cenozoic was not influenced by whether they were relatively fast or slow growers. By implication, environmental change acted directly to cause extinctions in slow-growing groups, rather than by increasing susceptibility to predation.
    • Growth-increment characteristics and isotopic (δ18O) temperature record of sub-thermocline Aequipecten opercularis (Mollusca:Bivalvia): evidence from modern Adriatic forms and an application to early Pliocene examples from eastern England.

      Johnson, Andrew; Valentine, Annemarie; Schöne, Bernd; Leng, Melanie; Sloane, Hilary; Janekovic, Ivica; University of Derby; Nottingham Trent University; University of Mainz, 55128 Mainz, Germany; National Environmental Isotope Facility, British Geological Survey, Keyworth; et al. (Elsevier, 2020-09-02)
      The shell δ18O of young modern Aequipecten opercularis from the southern North Sea provides an essentially faithful record of seasonal variation in seafloor temperature. In this well-mixed setting, A. opercularis shell δ18O also serves as a proxy for seasonal variation in surface temperature. Individuals from less agitated (e.g. deeper) settings in a warm climate would not be expected to record the full seasonal range in surface temperature because of thermal stratification in summer. Such circumstances have been invoked to explain cool isotopic summer temperatures from early Pliocene A. opercularis of eastern England. Support for a sub-thermocline setting derives from high-amplitude variation in microgrowth-increment size, which resembles the pattern in sub-thermocline A. opercularis from the southern Mediterranean Sea. Here, we present isotope and increment profiles from further sub-thermocline individuals, live-collected from a location in the Adriatic Sea for which we provide modelled values of expected shell δ18O. We also present data from supra-thermocline shells from the English Channel and French Mediterranean coast. The great majority of sub-thermocline A. opercularis show high-amplitude variation in increment size, and winter and summer δ18O values are generally quite close to expectation. However, the relatively warm summer conditions of 2015 are not recorded, in most cases due to a break in growth, perhaps caused by hypoxia. The supra-thermocline shells show subdued increment variation and yield isotopic winter and summer temperatures quite close to the local directly measured values. A. opercularis shells therefore provide a fairly good isotopic record of ambient temperature (if not always of relatively warm summer conditions below the thermocline) and their hydrographic setting can be determined from increment data. Early Pliocene examples from eastern England can be interpreted as having lived in a setting below the thermocline, with a higher seasonal range in surface temperature than now in the adjacent southern North Sea.
    • Habitat structure mediates biodiversity effects on ecosystem properties

      Godbold, J. A.; Bulling, Mark T.; Solan, Martin (2013-05-24)
      Much of what we know about the role of biodiversity in mediating ecosystem processes and function stems from manipulative experiments, which have largely been performed in isolated, homogeneous environments that do not incorporate habitat structure or allow natural community dynamics to develop. Here, we use a range of habitat configurations in a model marine benthic system to investigate the effects of species composition, resource heterogeneity and patch connectivity on ecosystem properties at both the patch (bioturbation intensity) and multi-patch (nutrient concentration) scale. We show that allowing fauna to move and preferentially select patches alters local species composition and density distributions, which has negative effects on ecosystem processes (bioturbation intensity) at the patch scale, but overall positive effects on ecosystem functioning (nutrient concentration) at the multi-patch scale. Our findings provide important evidence that community dynamics alter in response to localized resource heterogen- eity and that these small-scale variations in habitat structure influence species contributions to ecosystem properties at larger scales. We conclude that habitat complexity forms an important buffer against dis- turbance and that contemporary estimates of the level of biodiversity required for maintaining future multi-functional systems may need to be revised.
    • Habitat suitability, corridors and dispersal barriers for large carnivores in Poland

      Huck, Maren; Jędrzejewski, Włodzimierz; Borowik, Tomasz; Miłosz-Cielma, Małgorzata; Schmidt, Krzysztof; Jędrzejewska, Bogumiła; Nowak, Sabina; Mysłajek, Robert W.; Mammal Research Institute of the Polish Academy of Sciences; Association for Nature "Wolf" (2010)
      Carnivores are often particularly sensitive to landscape fragmentation. Ecological corridors may help to connect local populations, ensuring gene flow and retaining viable meta-populations. We aimed to establish habitat suitability models for two large carnivores in Poland, the grey wolf Canis lupus Linnaeus, 1758 and the Eurasian lynx Lynx lynx Linnaeus, 1758, based on ecological niche factor analysis (ENFA). Secondly, we calculated least cost paths (LCPs) based on cost values obtained from ENFA. Thirdly, we determined structures that might act as barriers, thus diminishing the value of the corridor unless appropriate conservation measures are taken. We compared some of the results with actual dispersal data of four lynx in eastern Poland. Results indicate that both species are highly marginalised. Less habitat that is currently available in Poland is suitable for lynx than for wolves. We determined a total of 76 LCPs. Comparison of these theoretical corridors with actual dispersal routes suggests that the traits of calculated LCPs are mostly within the range of those of real routes. We highlight a variety of features that might act as barriers, such as major roads (including planned highways), urbanized areas, and large un-forested areas. We give suggestions where concerted conservation efforts (eg wildlife passages) might be particularly well-directed.
    • Heat waves are a major threat to turbid coral reefs in Brazil

      Duarte, Gustavo A. S.; Villela, Helena D. M.; Deocleciano, Matheus; Silva, Denise; Barno, Adam; Cardoso, Pedro M.; Vilela, Caren L. S.; Rosado, Phillipe; Messias, Camila S. M. A.; Chacon, Maria Alejandra; et al. (Frontiers Media SA, 2020-03-30)
      Coral reefs are threatened by climate change on a global scale with thermal stress events and mass coral bleaching being widely reported. The reefs off the east coast of Brazil (and other turbid areas) have, however, historically escaped such thermal stress events, with relatively low levels of background coral mortality (5–10%). This has recently changed. Here we show that, in 2019, degree heating weeks (DHW) of 19.65 coincided with catastrophic declines in coral cover, especially in the major reef building hydrocoral Millepora alcicornis. The decline was due to bleaching associated with exposure to high temperature stress culminating in DHW values exceeding 15 for a period of 50 days. At two independent sites, surveys showed upwards of 83.5 ± 9.0 and 89.1 ± 3.9% mortality, and a third site showed relatively lower (albeit still high) mortality rates of 43.3 ± 12.0%. The mass die-off in 2019 is unprecedented in the South Atlantic reefs and coincides with increased heating events.
    • Herbicides increase the vulnerability of corals to rising sea surface temperature

      Negri, Andrew P.; Flores, Florita; Röthig, Till; Uthicke, Sven; Australian Institute of Marine Science, Townsville, Queensland, Australia (Wiley, 2011-02-03)
      In order to examine the potential interactive pressures of local pollution and global climate change, we exposed corals and crustose coralline algae (CCA) to three agricultural photosystem II (PSII) herbicides at four temperatures (26–32°C). The coral Acropora millepora was 3‐ to 10‐fold more sensitive to the three herbicides than the CCA Neogoniolithon fosliei. While the photosynthesis of CCA was not affected by the herbicide concentrations used (< 1 μg L−1), temperatures of 31°C and 32°C alone significantly inhibited photosynthetic efficiency (ΔF:F′m) and caused chronic photoinhibition (reduced Fv:Fm) and substantial bleaching. Environmentally relevant concentrations of each herbicide increased the negative effects of thermal stress on coral at 31°C and 32°C. Mixed model analyses of variance showed that the effects of elevated sea surface temperatures (SST) and herbicide on photosynthetic efficiency of coral symbionts were additive. Furthermore, the effect of either diuron or atrazine in combination with higher SST (31°C and 32°C) on chronic photoinhibition was distinctly greater than additive (synergistic). Reducing the herbicide concentration by 1 μg L−1 diuron above 30°C would protect photosynthetic efficiency by the equivalent of 1.8°C and reduce chronic photoinhibition by the equivalent of a 1°C reduction. Reduced water quality increases the vulnerability of corals to elevated SSTs, and effective management of local water quality can reduce negative effects of global stressors such as elevated SST.
    • High salinity tolerance of the Red Sea coral Fungia granulosa under desalination concentrate discharge conditions: an in situ photophysiology experiment.

      van der Merwe, Riaan; Röthig, Till; Voolstra, Christian R.; Ochsenkühn, Michael A.; Lattemann, Sabine; Amy, Gary L.; King Abdullah University of Science and Technology (KAUST) (Frontiers, 2014-11-10)
      Seawater reverse osmosis desalination concentrate may have chronic and/or acute impacts on the marine ecosystems in the near-field area of the discharge. Environmental impact of the desalination plant discharge is supposedly site- and volumetric- specific, and also depends on the salinity tolerance of the organisms inhabiting the water column in and around a discharge environment. Scientific studies that aim to understand possible impacts of elevated salinity levels are important to assess detrimental effects to organisms, especially for species with no mechanism of osmoregulation, e.g., presumably corals. Previous studies on corals indicate sensitivity toward hypo- and hyper-saline environments with small changes in salinity already affecting coral physiology. In order to evaluate sensitivity of Red Sea corals to increased salinity levels, we conducted a long-term (29 days) in situ salinity tolerance transect study at an offshore seawater reverse osmosis (SWRO) discharge on the coral Fungia granulosa. While we measured a pronounced increase in salinity and temperature at the direct outlet of the discharge structure, effects were indistinguishable from the surrounding environment at a distance of 5 m. Interestingly, corals were not affected by varying salinity levels as indicated by measurements of the photosynthetic efficiency. Similarly, cultured coral symbionts of the genus Symbiodinium displayed remarkable tolerance levels in regard to hypo- and hypersaline treatments. Our data suggest that increased salinity and temperature levels from discharge outlets wear off quickly in the surrounding environment. Furthermore, F. granulosa seem to tolerate levels of salinity that are distinctively higher than reported for other corals previously. It remains to be determined whether Red Sea corals in general display increased salinity tolerance, and whether this is related to prevailing levels of high(er) salinity in the Red Sea in comparison to other oceans.