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  • 1
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    PANGAEA
    In:  Supplement to: Manzello, Derek P; Enochs, I C; Bruckner, Andrew; Renaud, Philip G; Kolodziej, Graham; Budd, David A; Carlton, R; Glynn, Peter W (2014): Galápagos coral reef persistence after ENSO warming across an acidification gradient. Geophysical Research Letters, 41(24), 9001-9008, https://doi.org/10.1002/2014GL062501
    Publication Date: 2024-03-15
    Description: Anthropogenic CO2 is causing warming and ocean acidification. Coral reefs are being severely impacted, yet confusion lingers regarding how reefs will respond to these stressors over this century. Since the 1982-1983 El Niño-Southern Oscillation warming event, the persistence of reefs around the Galápagos Islands has differed across an acidification gradient. Reefs disappeared where pH〈8.0 and aragonite saturation state (Omega arag)〈=3 and have not recovered, whereas one reef has persisted where pH〉8.0 and Omega arag〉3. Where upwelling is greatest, calcification by massive Porites is higher than predicted by a published relationship with temperature despite high CO2, possibly due to elevated nutrients. However, skeletal P/Ca, a proxy for phosphate exposure, negatively correlates with density (R=-0.822, p〈0.0001). We propose that elevated nutrients have the potential to exacerbate acidification by depressing coral skeletal densities and further increasing bioerosion already accelerated by low pH.
    Keywords: Alkalinity, total; Aragonite saturation state; Benthos; Bicarbonate ion; Biomass/Abundance/Elemental composition; Calcification/Dissolution; Calcification rate; Calcification rate, standard error; Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; Coulometric titration; Date/time end; Date/time start; Density; Density, standard error; DEPTH, water; Depth, water, standard error; Entire community; Extension rate; Extension rate, standard error; Field observation; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; Phosphorus/Calcium ratio; Phosphorus/Calcium ratio, standard error; Potentiometric titration; Replicates; Rocky-shore community; Salinity; Site; South Pacific; Table; Temperature; Temperature, water; Tropical
    Type: Dataset
    Format: text/tab-separated-values, 260 data points
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Global change biology 2 (1996), S. 0 
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: Coral reef bleaching, the temporary or permanent loss of photosynthetic microalgae (zooxanthellae) and/or their pigments by a variety of reef taxa, is a stress response usually associated with anthropogenic and natural disturbances. Degrees of bleaching, within and among coral colonies and across reef communities, are highly variable and difficult to quantify, thus complicating comparisons of different bleaching events. Small-scale bleaching events can often be correlated with specific disturbances (e.g. extreme low/high temperatures, low/high solar irradiance, subaerial exposure, sedimentation, freshwater dilution, contaminants, and diseases), whereas large scale (mass) bleaching occurs over 100s to 1000s of km2, which is more difficult to explain. Debilitating effects of bleaching include reduced/no skeletal growth and reproductive activity, and a lowered capacity to shed sediments, resist invasion of competing species and diseases. Severe and prolonged bleaching can cause partial to total colony death, resulting in diminished reef growth, the transformation of reef-building communities to alternate, non-reef building community types, bioerosion and ultimately the disappearance of reef structures. Present evidence suggests that the leading factors responsible for large-scale coral reef bleaching are elevated sea temperatures and high solar irradiance (especially ultraviolet wavelengths), which may frequently act jointly.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 430 (2004), S. 741-741 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The long-term response of coral reefs to climate change depends on the ability of reef-building coral symbioses to adapt or acclimatize to warmer temperatures, but there has been no direct evidence that such a response can occur. Here we show that corals containing unusual algal symbionts that ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Annals of operations research 53 (1994), S. 175-197 
    ISSN: 1572-9338
    Keywords: Variance reduction ; simulation ; control variates ; importance sampling ; common random numbers ; stratification ; conditioning ; efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Notes: Abstract This paper provides an overview of the five most commonly used statistical techniques for improving the efficiency of stochastic simulations: control variates, common random numbers, importance sampling, conditional Monte Carlo, and stratification. The paper also describes a mathematical framework for discussion of efficiency issues that quantifies the trade-off between lower variance and higher computational time per observation.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Queueing systems 17 (1994), S. 107-128 
    ISSN: 1572-9443
    Keywords: Large deviations ; Gärtner-Ellis theorem ; counting processes ; point processes ; cumulant generating function ; waiting-time distribution ; small-tail asymptotics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We show, under regularity conditions, that a counting process satisfies a large deviations principle in ℝ or the Gärtner-Ellis condition (convergence of the normalized logarithmic moment generating functions) if and only if its inverse process does. We show, again under regularity conditions, that embedded regenerative structure is sufficient for the counting process or its inverse process to have exponential asymptotics, and thus satisfy the Gärtner-Ellis condition. These results help characterize the small-tail asymptotic behavior of steady-state distributions in queueing models, e.g., the waiting time, workload and queue length.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Annals of operations research 22 (1990), S. 1-21 
    ISSN: 1572-9338
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Notes: Abstract Our goal is to demonstrate for an important class of multistage stochastic models that three techniques — namely nested decomposition, Monte Carlo importance sampling, and parallel computing — can be effectively combined to solve this fundamental problem of large-scale linear programming.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Queueing systems 3 (1988), S. 221-255 
    ISSN: 1572-9443
    Keywords: Simulation ; queueing theory ; output analysis ; variance reduction ; generalized semi-Markov processes ; gradient estimation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper gives an overview of those aspects of simulation methodology that are (to some extent) peculiar to the simulation of queueing systems. A generalized semi-Markov process framework for describing queueing systems is used through much of the paper. The main topics covered are: output analysis for simulation of transient and steady-state quantities, variance reduction methods that exploit queueing structure, and gradient estimation methods for performance parameters associated with queueing networks.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 47 (1980), S. 287-290 
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Observations and experiments carried out on a coral reef off the Pacific coast of Panamá demonstrated that shrimp (Alpheus lottini) and crab (Trapezia spp.) symbionts that protect their host coral (Pocillopora elegans) can detect an approaching sea star predator (Acanthaster planci) by chemical cues. Simulated feeding attacks by Acanthaster in sealed transparent bags elicited only 0.5 defensive responses (snipping at spines and tube feet, jerking the sea star, and snapping) per 3 min; defensive behavior increased significantly to 4 and 5 responses, respectively, for Acanthaster in perforated bags and for Acanthaster in direct contact with coral. Neutralized (boiled) Acanthaster elicited only 3 defensive interactions per 3 min compared with 12 interactions for live Acanthaster. Simulated feeding attacks by Oreaster, a non-corallivorous sea star, elicited only 0.5 defensive responses per 3 min, whereas Oreaster introduced with “Acanthaster water” increased the level of defensive responses to 7. These results suggest that chemical, and to a lesser extent visual (physical presence and movements of sea star), cues stimulate the defensive behavior of the symbiotic crustaceans. The ability to detect a predator at a distance is probably advantageous because in responding only to an actual threat it minimizes the time the defending symbionts spend in an exposed position on the terminal branches of the host coral and because it alerts the crustaceans to sea stars feeding at night.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Coral reefs 1 (1983), S. 215-222 
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The timing of skeletal band formation and concomitant changes in calcification rates and linear skeletal extension were investigated in Pavona corals growing under two distinct thermal regimes along the Pacific coast of Panama: fluctuating, marked by seasonal upwelling (Gulf of Panama) and stable, nonupwelling (Gulf of Chiriqui). The purpose of this study was to test the hypothesis that banding in corals is largely mediated by seasonal variations in temperature (Highsmith 1979). Our results indicate that the timing of band formation is synchronous at these two environmentally distinct locations. The low density (LD) portion of the annual band is accreted over a five month period (January–June) and represents an increase in linear skeletal extension (mm/mo.) as well as a marked increase in calcification rate (g CaCO3 · cm-2 · mo-1) relative to the high density portion which forms over the remaining seven month period (July through December). In contrast to the predictions of the Highsmith model these findings indicate that variations in light levels rather than fluctuation in temperature is a better correlate to changes in skeletal density. Qualitatively, banding patterns were similar at the two sites; however, higher growth rates (particularly with respect to the LD band) for Pavona clavus in the Gulf of Panama indicate that lower water temperatures and higher productivity, or both, may be responsible for quantitative differences in banding between sites. We found that formation of the HD band corresponds to lower light levels and the production of gametes. We propose that banding in corals is a complex phenomenon governed by endogenous processes (e.g. reallocation of energy from growth to reproduction) which may be mediated by exogenous factors (e.g light and productivity).
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  • 10
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Approximately 550 measurements of Mn/Ca ratios in three corals from the western Galapagos Islands have been performed to reconstruct a 380-year history of surface ocean variability with respect to this trace element. The time period studied encompasses 1600 A.D. to 1978. Manganese is inferred to be lattice-bound in coralline aragonite at 10–50% of its seawater proportion to calcium; uncertainty about the distribution coefficient stems from inherent variability of oceanic Mn in nearshore settings. Interannual variations at Urvina Bay, Isabela Island are generally small, with the exception of a few decades during the nineteenth century. A large positive Mn/Ca anomaly found between 1821–1830 is hypothesized to have resulted from a major volcanic eruption on nearby Fernandina Island in 1825. On intrannual timescales a pronounced cycle occurs in response to seasonal upwelling. Quarterly changes in Mn/Ca are six months out-of-phase with Cd/Ca variations-a reflection of the opposite distributions of these metals in the upper waters of the eastern Pacific. High frequency reconstructions over brief time intervals from the 17th, 18th, and 20th century reveal that the seasonal onset of warm and cool phases near Galapagos has persisted for at least 340 years. A quantitative assessment of historical changes in upwelling intensity is complicated by offsets in background Mn levels recorded by different corals. One apparent longterm feature is an overall decline in skeletal Mn concentrations from 1600–1978 which results in a net decrease of 20–30%. Several possible explanations exist for this trend, ranging from accumulation of a persistent diagenetic Mn phase in fossil aragonite to a temporal shift in oceanic/atmospheric Mn fluxes reaching the surface waters of the Galapagos Islands.
    Type of Medium: Electronic Resource
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