scholarly journals Scaling the effects of ocean acidification on coral growth and coral–coral competition on coral community recovery

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11608
Author(s):  
Nicolas R. Evensen ◽  
Yves-Marie Bozec ◽  
Peter J. Edmunds ◽  
Peter J. Mumby
Keyword(s):  
Ocean Acidification ◽  
Spatial Scales ◽  
Coral Community ◽  
Coral Growth ◽  
Short Term ◽  
Recovery Rates ◽  
Community Recovery ◽  
Fore Reef ◽  
Combining Data ◽  
Coral Communities

Ocean acidification (OA) is negatively affecting calcification in a wide variety of marine organisms. These effects are acute for many tropical scleractinian corals under short-term experimental conditions, but it is unclear how these effects interact with ecological processes, such as competition for space, to impact coral communities over multiple years. This study sought to test the use of individual-based models (IBMs) as a tool to scale up the effects of OA recorded in short-term studies to community-scale impacts, combining data from field surveys and mesocosm experiments to parameterize an IBM of coral community recovery on the fore reef of Moorea, French Polynesia. Focusing on the dominant coral genera from the fore reef, Pocillopora, Acropora, Montipora and Porites, model efficacy first was evaluated through the comparison of simulated and empirical dynamics from 2010–2016, when the reef was recovering from sequential acute disturbances (a crown-of-thorns seastar outbreak followed by a cyclone) that reduced coral cover to ~0% by 2010. The model then was used to evaluate how the effects of OA (1,100–1,200 µatm pCO2) on coral growth and competition among corals affected recovery rates (as assessed by changes in % cover y−1) of each coral population between 2010–2016. The model indicated that recovery rates for the fore reef community was halved by OA over 7 years, with cover increasing at 11% y−1 under ambient conditions and 4.8% y−1 under OA conditions. However, when OA was implemented to affect coral growth and not competition among corals, coral community recovery increased to 7.2% y−1, highlighting mechanisms other than growth suppression (i.e., competition), through which OA can impact recovery. Our study reveals the potential for IBMs to assess the impacts of OA on coral communities at temporal and spatial scales beyond the capabilities of experimental studies, but this potential will not be realized unless empirical analyses address a wider variety of response variables representing ecological, physiological and functional domains.

scholarly journals Changes in coral reef communities across a natural gradient in seawater pH

2015 ◽  
Vol 1 (5) ◽  
pp. e1500328 ◽  
Author(s):  
Hannah C. Barkley ◽  
Anne L. Cohen ◽  
Yimnang Golbuu ◽  
Victoria R. Starczak ◽  
Thomas M. DeCarlo ◽  
...  
Keyword(s):  
Coral Reef ◽  
Ocean Acidification ◽  
Benthic Communities ◽  
Coral Community ◽  
Low Ph ◽  
Coralline Algae ◽  
Negative Effects ◽  
Skeletal Density ◽  
Coral Communities ◽  
Coral Reef Ecosystems

Ocean acidification threatens the survival of coral reef ecosystems worldwide. The negative effects of ocean acidification observed in many laboratory experiments have been seen in studies of naturally low-pH reefs, with little evidence to date for adaptation. Recently, we reported initial data suggesting that low-pH coral communities of the Palau Rock Islands appear healthy despite the extreme conditions in which they live. Here, we build on that observation with a comprehensive statistical analysis of benthic communities across Palau’s natural acidification gradient. Our analysis revealed a shift in coral community composition but no impact of acidification on coral richness, coralline algae abundance, macroalgae cover, coral calcification, or skeletal density. However, coral bioerosion increased 11-fold as pH decreased from the barrier reefs to the Rock Island bays. Indeed, a comparison of the naturally low-pH coral reef systems studied so far revealed increased bioerosion to be the only consistent feature among them, as responses varied across other indices of ecosystem health. Our results imply that whereas community responses may vary, escalation of coral reef bioerosion and acceleration of a shift from net accreting to net eroding reef structures will likely be a global signature of ocean acidification.

scholarly journals Greater Mitochondrial Energy Production Provides Resistance to Ocean Acidification in “Winning” Hermatypic Corals

2021 ◽  
Vol 7 ◽  
Author(s):  
Sylvain Agostini ◽  
Fanny Houlbrèque ◽  
Tom Biscéré ◽  
Ben P. Harvey ◽  
Joshua M. Heitzman ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Energy Production ◽  
Coral Species ◽  
Tissue Growth ◽  
Physiological Traits ◽  
Transport Systems ◽  
Current Evidence ◽  
Short Term ◽  
The World ◽  
Coral Communities

Coral communities around the world are projected to be negatively affected by ocean acidification. Not all coral species will respond in the same manner to rising CO2 levels. Evidence from naturally acidified areas such as CO2 seeps have shown that although a few species are resistant to elevated CO2, most lack sufficient resistance resulting in their decline. This has led to the simple grouping of coral species into “winners” and “losers,” but the physiological traits supporting this ecological assessment are yet to be fully understood. Here using CO2 seeps, in two biogeographically distinct regions, we investigated whether physiological traits related to energy production [mitochondrial electron transport systems (ETSAs) activities] and biomass (protein contents) differed between winning and losing species in order to identify possible physiological traits of resistance to ocean acidification and whether they can be acquired during short-term transplantations. We show that winning species had a lower biomass (protein contents per coral surface area) resulting in a higher potential for energy production (biomass specific ETSA: ETSA per protein contents) compared to losing species. We hypothesize that winning species inherently allocate more energy toward inorganic growth (calcification) compared to somatic (tissue) growth. In contrast, we found that losing species that show a higher biomass under reference pCO2 experienced a loss in biomass and variable response in area-specific ETSA that did not translate in an increase in biomass-specific ETSA following either short-term (4–5 months) or even life-long acclimation to elevated pCO2 conditions. Our results suggest that resistance to ocean acidification in corals may not be acquired within a single generation or through the selection of physiologically resistant individuals. This reinforces current evidence suggesting that ocean acidification will reshape coral communities around the world, selecting species that have an inherent resistance to elevated pCO2.

scholarly journals Spatial resolution of tropical terrestrial CO<sub>2</sub> fluxes inferred using space-borne column CO<sub>2</sub> sampled in different earth orbits: the role of spatial error correlations

2011 ◽  
Vol 4 (9) ◽  
pp. 1995-2006 ◽  
Author(s):  
P. I. Palmer ◽  
L. Feng ◽  
H. Bösch
Keyword(s):  
Spatial Resolution ◽  
Spatial Scales ◽  
Space Station ◽  
Co2 Flux ◽  
Model Errors ◽  
Spatial Error ◽  
Clear Sky ◽  
Free Data ◽  
Combining Data ◽  
Infrared Measurements

Abstract. We use realistic numerical experiments to assess the sensitivity of 8-day CO2 flux estimates, inferred from space-borne short-wave infrared measurements of column-averaged CO2 dry air mixing ratio XCO2, to the choice of Earth observing orbit. We focus on three orbits: (1) a low-inclination circular orbit used by the NASA Tropical Rainfall Measuring Mission (TRMM); (2) a sun-synchronous orbit used by the Japanese Greenhouse Gases Observing SATellite (GOSAT) and proposed for the NASA Orbiting Carbon Observatory (OCO-2) instrument; and (3) a precessing orbit used by the International Space Station (ISS). For each orbit, we assume an instrument based on the specification of the OCO-2; for GOSAT we use the relevant instrument specification. Sun-synchronous orbits offer near global coverage within a few days but have implications for the density of clear-sky measurements. The TRMM and ISS orbits intensively sample tropical latitudes, with sun-lit clear-sky measurements evenly distributed between a.m./p.m. For a specified spatial resolution for inferred fluxes, we show there is a critical number of measurements beyond which there is a disproportionately small decrease in flux uncertainty. We also show that including spatial correlations for measurements and model errors (of length 300 km) reduces the effectiveness of high measurement density for flux estimation, as expected, and so should be considered when deciding sampling strategies. We show that cloud-free data from the TRMM orbit generally can improve the spatial resolution of CO2 fluxes achieved by OCO-2 over tropical South America, for example, from 950 km to 630 km, and that combining data from these low-inclination and sun-synchronous orbits have the potential to reduce this spatial length further. Decreasing the length of the error correlations to 50 km, reflecting anticipated future improvements to transport models, results in CO2 flux estimates on spatial scales that approach those observed by regional aircraft.

Housing Disinvestment and Crime in a Phoenix Suburb: Exploring the Differential Effects of Investors and Owner-Occupants

2016 ◽  
Vol 54 (1) ◽  
pp. 190-224 ◽  
Author(s):  
Alyssa W. Chamberlain ◽  
Danielle Wallace ◽  
Deirdre Pfeiffer ◽  
Janne Gaub
Keyword(s):  
Large Scale ◽  
Property Crime ◽  
Crime Rates ◽  
Housing Crisis ◽  
Short Term ◽  
Sociodemographic Data ◽  
Combining Data ◽  
Home Sales ◽  
The Impact

External investment in neighborhoods can inhibit crime. However, during the housing crisis, many investors were foreclosed upon, triggering large-scale community disinvestment. Yet the impact of this type of disinvestment on crime is currently unknown. Combining data on crime incidents with foreclosure, home sales, and sociodemographic data, this research assesses whether the foreclosure of properties owned by investors has an effect on crime in neighborhoods in Chandler, Arizona, a suburb in the heavily affected Phoenix region. Neighborhoods with a greater proportion of foreclosures on investors (FOIs) have higher total and property crime rates in the short term. In Hispanic neighborhoods, a greater proportion of FOIs result in lower rates of crime. Results suggest that neighborhood stabilization efforts should consider the role of investors in driving short-term crime rates, and that police and code enforcement strategies might prioritize neighborhoods with a high proportion of investor foreclosures.

scholarly journals Scaling Relations between Gas and Star Formation in Nearby Galaxies

2010 ◽  
Vol 6 (S270) ◽  
pp. 327-334 ◽  
Author(s):  
Frank Bigiel ◽  
Adam Leroy ◽  
Fabian Walter
Keyword(s):  
Star Formation ◽  
Spatial Scales ◽  
Formation Rate ◽  
Star Forming ◽  
Multiple Regimes ◽  
Combining Data ◽  
Multi Wavelength ◽  
Nearby Galaxies ◽  
Physical Quantities ◽  
Individual Galaxy

AbstractHigh resolution, multi-wavelength maps of a sizeable set of nearby galaxies have made it possible to study how the surface densities of H i, H2 and star formation rate (ΣHI, ΣH2, ΣSFR) relate on scales of a few hundred parsecs. At these scales, individual galaxy disks are comfortably resolved, making it possible to assess gas-SFR relations with respect to environment within galaxies. ΣH2, traced by CO intensity, shows a strong correlation with ΣSFR and the ratio between these two quantities, the molecular gas depletion time, appears to be constant at about 2 Gyr in large spiral galaxies. Within the star-forming disks of galaxies, ΣSFR shows almost no correlation with ΣHI. In the outer parts of galaxies, however, ΣSFR does scale with ΣHI, though with large scatter. Combining data from these different environments yields a distribution with multiple regimes in Σgas – ΣSFR space. If the underlying assumptions to convert observables to physical quantities are matched, even combined datasets based on different SFR tracers, methodologies and spatial scales occupy a well define locus in Σgas – ΣSFR space.

scholarly journals Predicting coral community recovery using multi-species population dynamics models

2018 ◽  
Vol 21 (12) ◽  
pp. 1790-1799 ◽  
Author(s):  
Mohsen Kayal ◽  
Hunter S. Lenihan ◽  
Andrew J. Brooks ◽  
Sally J. Holbrook ◽  
Russell J. Schmitt ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Coral Community ◽  
Community Recovery ◽  
Species Population ◽  
Population Dynamics Models ◽  
Dynamics Models

scholarly journals Ocean Acidification Has Impacted Coral Growth on the Great Barrier Reef

2020 ◽  
Vol 47 (19) ◽  
Author(s):  
Weifu Guo ◽  
Rohit Bokade ◽  
Anne L. Cohen ◽  
Nathaniel R. Mollica ◽  
Muriel Leung ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Ocean Acidification ◽  
Coral Growth ◽  
Barrier Reef

scholarly journals Short-Term Prediction of Bus Passenger Flow Based on a Hybrid Optimized LSTM Network

2019 ◽  
Vol 8 (9) ◽  
pp. 366 ◽  
Author(s):  
Yong Han ◽  
Cheng Wang ◽  
Yibin Ren ◽  
Shukang Wang ◽  
Huangcheng Zheng ◽  
...  
Keyword(s):  
High Efficiency ◽  
Short Term Memory ◽  
Spatial Scales ◽  
Optimization Procedure ◽  
Stochastic Gradient Descent ◽  
Short Term ◽  
Passenger Flow ◽  
Proposed Model ◽  
Gradient Descent Algorithm ◽  
Lstm Network

The accurate prediction of bus passenger flow is the key to public transport management and the smart city. A long short-term memory network, a deep learning method for modeling sequences, is an efficient way to capture the time dependency of passenger flow. In recent years, an increasing number of researchers have sought to apply the LSTM model to passenger flow prediction. However, few of them pay attention to the optimization procedure during model training. In this article, we propose a hybrid, optimized LSTM network based on Nesterov accelerated adaptive moment estimation (Nadam) and the stochastic gradient descent algorithm (SGD). This method trains the model with high efficiency and accuracy, solving the problems of inefficient training and misconvergence that exist in complex models. We employ a hybrid optimized LSTM network to predict the actual passenger flow in Qingdao, China and compare the prediction results with those obtained by non-hybrid LSTM models and conventional methods. In particular, the proposed model brings about a 4%–20% extra performance improvements compared with those of non-hybrid LSTM models. We have also tried combinations of other optimization algorithms and applications in different models, finding that optimizing LSTM by switching Nadam to SGD is the best choice. The sensitivity of the model to its parameters is also explored, which provides guidance for applying this model to bus passenger flow data modelling. The good performance of the proposed model in different temporal and spatial scales shows that it is more robust and effective, which can provide insightful support and guidance for dynamic bus scheduling and regional coordination scheduling.

The Impact of Acanthaster on Corals and Coral Reefs in the Eastern Pacific

1974 ◽  
Vol 1 (4) ◽  
pp. 295-304 ◽  
Author(s):  
Peter W. Glynn
Keyword(s):  
Species Diversity ◽  
Field Work ◽  
Coral Community ◽  
Eastern Pacific ◽  
Live Coral ◽  
Sea Star ◽  
Coral Communities ◽  
Negative Effect ◽  
Population Sizes ◽  
The Impact

The movement of surface currents and the availability of coral prey are probably not responsible for the discontinuities in the distribution of Acanthaster (the Crown-of-thorns Starfish or Sea-star) in American waters. Temperature and salinity conditions are critical in development, and it is possible that these parameters are effective locally, for example in the Gulf of Panamá. There is a strong possibility that continuing field work will show that Acanthaster has a significantly more widespread distribution in the eastern Pacific than is currently known.Adult Acanthaster and several species of coral prey exhibited an unusually high tolerance to varying conditions of temperature and salinity. The possibility of step-wise colonization to new areas, mediated by resistant adult populations that can become established during favourable seasons, should be considered in any plans to alter the existing freshwater canal in Panamá. For introductions can be environmentally dangerous.The highest population densities of Acanthaster so far observed in the eastern Pacific, 1 individual/40 m2 to approximately 1 individual/100 m2, are comparable to population sizes in the Indo-Pacific region that are not considered to have a serious impact on coral communities. Coral destruction by Acanthaster can be significant in certain limited areas, but is usually less than that caused by other corallivores.An analysis of coral community structure in relation to Acanthaster density failed to show a significant correlation with (a) number of species, (b) number of live coral colonies, (c) species diversity (H'), or (d) species evenness (J').Prey preference data indicate that Acanthaster selectively destroys rare corals. Replacement of rare, predated corals by fast-growing species (Pocillopora spp.) has been observed in the field, showing that Acanthaster could have a negative effect on species diversity.

scholarly journals Congruence between automatic fish counter data and rod catches of Atlantic salmon (Salmo salar) in Scottish rivers

2005 ◽  
Vol 62 (4) ◽  
pp. 808-817 ◽  
Author(s):  
J.L. Thorley ◽  
D.M.R. Eatherley ◽  
A.B. Stephen ◽  
I. Simpson ◽  
J.C. MacLean ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Spatial Scales ◽  
Short Term ◽  
Atlantic Salmon Salmo Salar ◽  
Residual Variation ◽  
Term Variation ◽  
Temporal And Spatial ◽  
Counter Data

Abstract The potential utility of rod catch and automatic fish counter data as measures of Atlantic salmon (Salmo salar) abundance in Scottish rivers was assessed. The trend (long-term) and residual (short-term) variation in the net annual count for 12 counters were compared with the trend and residual variation in either the annual or spring (February–May) rod catch, as appropriate, for the fisheries district in which the counter is located. Trends were fitted using a cubic smoothing spline and compared using reference bands. In eight of the 12 short-term comparisons, the residuals were significantly correlated. The four incongruent short-term comparisons involved the shortest time-series (≤12 years) or lowest rod catches. In eight of the 12 long-term comparisons, the trends fell within the reference bands in 50% or more of the years. Rod catch and counter data both contain useful information about Atlantic salmon abundance, albeit on different temporal and spatial scales, which should be integrated into assessment schemes.

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