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opencc-by-4.0Jan 2022View details →

Tropical extreme droughts drive long-term increase in atmospheric CO2 growth rate variability

This repository includes the code and the processed climate data used to examine the long-term change in atmospheric CO2 growth rate. The code will generate the main figures (Figure 1, 2 and 3) in the paper - Luo, X. & Keenan, T. F. (2022) Tropical extreme droughts drive long-term increase in atmospheric CO2 growth rate variability. Nature Communications, doi: 10.1038/s41467-022-28824-5. Please refer to the "Data Availability Statement" in the paper and cite the original sources if you need to use one or more datasets published here. There are three files in the repository: 1) CGR_analysis_input.mat is the processed data in matlab format to support the study; 2) master_figures_CGR_publish_v1.m is the main matlab routine that used to generate figures; 3) supporting code is a folder that contains third-party routines to support the main routine.

opencc-zeroMar 2022View details →

10Be concentrations constraining surface age and valley growth rate in a seepage-derived drainage network in the Apalachicola River basin, Florida

Measuring rates of valley head migration and determining the timing of canyon-opening are insightful quantifications for the history and evolution of planetary surfaces. Horizontal spatial gradients of in situ-produced cosmogenic nuclide concentrations provide a framework for assessing the migration of these and similar topographic features. We developed a theoretical model for the concentration of in situ produced cosmogenic radionuclides in valley walls during retreat of a valley head. The retreat rate is inversely proportional to the magnitude of the spatial concentration gradient and proportional to local nuclide accumulation rates. By solving for a spatial gradient in concentration along a valley parallel transect, we created an expression for the explicit determination of valley head retreat, termed unzipping. We applied this theory to a developing seepage-derived drainage network along the Apalachicola River, Florida, USA. Sample concentrations along a valley margin transect vary systematically from 2.9 x 105 atoms/g to 3.5 x 105 atoms/g resulting in a gradient of 160 atoms/g/m, and from this value a valley head retreat rate of 0.025 m/y is found. The discrepancy between overall network age and current rates of valley head migration suggests intermittent network growth which is consistent with glacial-interglacial precipitation variations during the Pleistocene. This method can be applied to a wide range of Earth-surface environments. For the 10Be system, this method should be sensitive to unzipping rates bounded between 10-6 m/y and 100 m/y.

opencc-zeroApr 2022View details →

Demographic rates and stature of tree species in 13 sub-tropical forests: annual growth, annual survival, annual recruitment >( 1 cm dbh), stature (max dbh)

Organisms of all species must balance their allocation to growth, survival and recruitment. Among tree species, evolution has resulted in different life-history strategies for partitioning resources to these key demographic processes. Life-history strategies in tropical forests have often been shown to align along a trade-off between fast growth and high survival, i.e. the well-known fast-slow continuum. In addition, an orthogonal trade-off has been proposed between tall stature – resulting from fast growth and high survival – and recruitment success, i.e. a stature−recruitment trade-off. However, it is not clear if these two independent dimensions of life-history variation structure tropical forests worldwide. We used data from 13 large-scale and long-term tropical forest monitoring plots in three continents to explore the principal trade-offs in annual growth, survival and recruitment as well as tree stature. These forests included relatively undisturbed forests as well as typhoon-disturbed forests. Life-history variation in twelve forests was structured by two orthogonal trade-offs, the growth−survival trade-off and the stature−recruitment trade-off. Pairwise Procrustes analysis revealed a high similarity of demographic relationships among forests. The small deviations were related to differences between African and Asian plots. Synthesis. The fast-slow continuum and tree stature are two independent dimensions structuring many, but not all tropical tree communities. Our discovery of the consistency of demographic trade-offs and life-history strategies across different forest types from three continents substantially improves our ability to predict tropical forest dynamics worldwide.

opencc-zeroJul 2022View details →

Chain length, growth rate and clearance rate of Thalassiosira Rotula, Chaetoceros Curvisetus, and Chaetoceros Affinis when exposed to copepodamides.

Colony formation is common feature among non-motile marine phytoplankton. Several theories exist around the potential benefits of larger colonies. Here we test the hypothesis that predation is one of the drivers behind colony formation and chain length plasticity. We exposed cultures of Thalassiosira rotula, Chaetoceros curvisetus and Chaetoceros affinis to copepodamides, a chemical alarm cue released by copepods and perceived as an indicator of predation threat by their prey. This was coupled with a grazing experiment which compared copepod grazing rates on different chain lengths. Our results show that T. rotula and C. curvisetus decreased their chain lengths by 79% and 49%, respectively, in response to copepodamides. Single cells and short chains were grazed at lower rates compared to long chains and the copepodamide driven size shift led to 30% and 12% lower grazing in T. rotula and C. curvisetus respectively. In contrast, C. affinis showed a slight increased chain length in response to copepodamides although non-significant. We found that 2 of 3 studied species reduce their chain length in response to the presence copepod grazers. Altered size structure has implications for the route of carbon in the marine food webs and carbon export to deeper strata.

opencc-zeroJul 2022View details →

Data from: Harvesting has variable effects on demographic rates and population growth across three dry forest tree species

Understanding how anthropogenic activities, such as harvesting, influence plant populations is important to quantify sustainable practices that conserve species of socioeconomic importance. There is limited knowledge on how harvesting of branches and non-timber forest products affect populations of trees in the dry tropics. We measure demographic vital rates of three dry tropical tree species in the presence and absence of harvesting and apply integral projection models to quantify population growth rates, which represent the mean fitness across the life cycle. Our results show that the three species vary in their demographic rates and life history. Harvesting significantly decreases the growth of two species. Current levels of harvesting only significantly decreased the population growth rate of one species that experienced both branch and main stem harvesting. Life table response experiments reveal that the negative effect of harvesting on the population growth rate of this species is primarily due to individuals being forced to re-sprout from their base. Few individuals were observed recruiting from seed, and this might be due to the presence of other threats, such as fire, soil erosion, and grazing. Our results provide knowledge on the demography and the effects of harvesting on endemic tree species of the Eastern Ghats, a region for which few demographic studies are available. These results are relevant to conserving forest biodiversity for the benefits of people and can contribute to quantitative threat assessment for IUCN red listing.

opencc-zeroAug 2022View details →

Growth rates of populations evolved and assayed at two temperatures for 6500 generations

Evolutionary biologists have long sought to understand what factors affect the repeatability of adaptive outcomes. To better understand the role of temperature in determining the repeatability of adaptive trajectories, we evolved populations of different genotypes of the ciliate Tetrahymena thermophila at low and high temperatures and followed changes in growth rate over 6,500 generations. As expected, growth rate increased with a decelerating rate for all populations; however, there were differences in the patterns of evolution at the two temperatures. The growth rates of the different genotypes tended to converge as evolution proceeded at both temperatures, but this convergence was quicker and more pronounced at the higher temperature. Additionally, over the first 4,000 generations we found greater repeatability of evolution, in terms of change in growth rate, among replicates of the same genotype at the higher temperature. Finally, we found limited evidence of trade-offs in fitness between temperatures, and an asymmetry in the correlated responses, whereby evolution in a high temperature increases growth rate at the lower temperature significantly more than the reverse. These results demonstrate the importance of temperature in determining the repeatability of evolutionary trajectories for the eukaryotic microbe Tetrahymena thermophila and may provide clues to how temperature affects evolution more generally.

FIGURE 5 in Observations on growth rate and allometry in the seasonal predatory killifish Nothobranchius ocellatus (Teleostei: Cyprinodontiformes)

FIGURE 5. Graphical representation of the most important allometric growth changes in morphometric parameters as measured for the three subject specimens of Nothobranchius ocellatus, through the sub-adult to young sexually mature phases, at 37, 56 and 84 days after hatching. Data from Table 2.

FIGURE 6 in Observations on growth rate and allometry in the seasonal predatory killifish Nothobranchius ocellatus (Teleostei: Cyprinodontiformes)

FIGURE 6. Comparative morphometry of growth in selected specimens of Nothobranchius ocellatus; a, Score plot of principal component analysis (PCA) on morphometric characters; first vs. second principal components: female #1 (diamond), male #2 (circle), male #4 (inverted triangle); b, loading plot of PCA for female #1; c, loading plot of PCA for male #2; d, loading plot of PCA for male #4. Most important loadings with absolute magnitude greater than 0.4 appear in bold. Key to character abbreviations: TL, Total length; BD, Body depth at pelvic–fin origin; HL, Head length; PA, Preanal length; PD, Predorsal length; PV, Prepelvic length; PP, Prepectoral length; CPL, Caudal peduncle length; CPD, Caudal peduncle depth; DFB, Dorsal-fin base length; AFB, Anal-fin base length; CF, Caudal-fin length; HD, Head depth; PO, Postorbital length; SD, Suborbital depth; ED, Eye diameter; SEL, Snout to eye end length; SL, Snout length.

FIGURE 4 in Observations on growth rate and allometry in the seasonal predatory killifish Nothobranchius ocellatus (Teleostei: Cyprinodontiformes)

FIGURE 4. Sets of photographs (A, B and C) showing the development of sex distinction as reflected in changes in colour pattern, and some general morphological features, in the study specimens of Nothobranchius ocellatus at 37, 58 and 84 days age.

FIGURE 2 in Observations on growth rate and allometry in the seasonal predatory killifish Nothobranchius ocellatus (Teleostei: Cyprinodontiformes)

FIGURE 2. Illustration of the method used for measuring the total length (TL) of Nothobranchius ocellatus specimens on a weekly basis. Specimens were placed in very shallow water in a clear, flat-bottomed glass dish (of a size suited to the size of the specimen) over graph paper and photographed from above. A straight line was then digitally drawn from the terminus of the upper jaw to the posterior margin of the caudal fin. The line was then rotated into alignment with the grid of the graph paper in order to closely approximate TL.

FIGURE 1 in Observations on growth rate and allometry in the seasonal predatory killifish Nothobranchius ocellatus (Teleostei: Cyprinodontiformes)

FIGURE 1. Nothobranchius ocellatus: upper, wild-caught male from neotype locality (field code: Kikongono TAN 95-9); lower, wild-caught female (field code: Kitonga south TAN 97-36); Rufiji River drainage; central coastal region, Tanzania.

opencc-zeroOct 2022View details →

Growth model used in Guzy et al. Increased growth rates of stream salamanders following forest harvesting

Timber harvesting can influence headwater streams by altering stream productivity, with cascading effects on the food web and predators within, including stream salamanders. Although studies have examined shifts in occupancy or abundance following timber harvest, few examine sublethal effects such as changes in growth and demography. To examine the effect of upland harvesting on growth of the stream-associated Ouachita dusky salamander (Desmognathus brimleyorum), we used capture-mark-recapture over three years at three headwater streams embedded in intensely managed pine forests in west-central Arkansas. The pine stands surrounding two of the streams were harvested, with retention of a 14 and 21 m-wide forested stream buffer on each side of the stream, whereas the third stream was an unharvested control. At the two treatment sites, measurements of newly-metamorphosed salamanders were on average 4.0 and 5.7 mm larger post-harvest compared to pre-harvest. We next assessed the influence of timber harvest on growth of post-metamorphic salamanders with a hierarchical von Bertalanffy growth model that included an effect of harvest on growth rate. Using measurements from 839 individual D. brimleyorum recaptured between 1 and 6 times (total captures n=1,229) we found growth rates to be 1.4 times higher post-harvest. Our study is among the first to examine responses of individual stream salamanders to timber harvesting and we discuss mechanisms that may be responsible for observed shifts in growth. Our results suggest timber harvest that includes retention of a riparian buffer (i.e., Streamside Management Zone) may have short term positive effects on juvenile stream salamander growth, potentially offsetting negative sublethal effects associated with harvest.

opencc-by-4.0Feb 2024View details →

New Expression of the Field-line Integrated Rayleigh-Taylor Instability Growth Rate

The data provided in correlation with the journal article bearing the same title.

opencc-by-4.0Oct 2024View details →

The influence of wet feed distribution on the density, growth rate and growth variability of Tenebrio molitor

Open the record for dataset details and reuse information.

opencc-zeroDec 2014View details →

Data from: Positive selection in development and growth rate regulation genes involved in species divergence of the genus Radix

Background: Life history traits like developmental time, age and size at maturity are directly related to fitness in all organisms and play a major role in adaptive evolution and speciation processes. Comparative genomic or transcriptomic approaches to identify positively selected genes involved in species divergence can help to generate hypotheses on the driving forces behind speciation. Here we use a bottom-up approach to investigate this hypothesis by comparative analysis of orthologous transcripts of four closely related European Radix species. Results: Snails of the genus Radix occupy species specific distribution ranges with distinct climatic niches, indicating a potential for natural selection driven speciation based on ecological niche differentiation. We then inferred phylogenetic relationships among the four Radix species based on whole mt-genomes plus 23 nuclear loci. Three different tests to infer selection and changes in amino acid properties yielded a total of 134 genes with signatures of positive selection. The majority of these genes belonged to the functional gene ontology categories "reproduction" and "genitalia" with an overrepresentation of the functions "development" and "growth rate". Conclusions: We show here that Radix species divergence may be primarily enforced by selection on life history traits such as (larval-) development and growth rate. We thus hypothesise that life history differences may confer advantages under the according climate regimes, e.g., species occupying warmer and dryer habitats might have a fitness advantage with fast developing susceptible life stages, which are more tolerant to habitat desiccation.

opennotspecifiedNov 2008View details →

Figure 2 in Growth rates of wild green turtles, Chelonia mydas, at a temperate foraging habitat in the northern Gulf of Mexico: assessing short-term effects of cold-stunning on growth

Figure 2. Graphical summary of generalized additive model fit for somatic growth, in cm straight carapace length (SCL)/year, for St Joseph Bay, Florida conditioned on two growthrate predictors: (A,B) number of previous cold-stunning events and mean carapace length or (C,D) number of previous cold-stunning events and mean condition index. The response variable (growth rate as cm SCL/year) is shown on the y-axis in each panel as a centred scale to ensure valid point-wise 95% credible intervals and comparison between the covariates across the four panels. The width of the mean factor response (number of previous cold-stunning events: A,C) is proportional to sample size with the 95% confidence interval shown by cross bars. Solid curves in B and D are cubic smoothing spline fits for these continuous covariates conditioned on the cofactor (previous cold-stunnings) while the dotted curves in the same panels are point-wise 95% confidence curves around the fits. The data distribution within (B) and (D) is shown by the vertical bars on the topside of the lower x-axis. For instance, (D) shows that most of the data for the mean condition index occur from 1.1 to 1.5 with some extreme outliers. While not statistically significant, it was apparent that expected growth rates were lower for turtles that were exposed to one or two cold-stunning events (A,C). Neither mean size (B) nor mean condition (D) were significant growth-rate predictors for this sample. The sample size (n551) is too small for this study to draw any robust conclusions about the effect of cold-stunning events on juvenile green turtle somatic growth.

opennotspecifiedNov 2008View details →

Figure 1 in Growth rates of wild green turtles, Chelonia mydas, at a temperate foraging habitat in the northern Gulf of Mexico: assessing short-term effects of cold-stunning on growth

Figure 1. Location of St Joseph Bay in the northern Gulf of Mexico. Major set-netting sites (filled circles) used throughout the project and location of cold stun strandings (solid arrows) during 2001 and 2003. Site of release (indicated by star) into the Gulf of Mexico after rehabilitation, and the possible path (thin arrows) taken while returning to the southern end of St Joseph Bay.

opennotspecifiedJul 2010View details →

Figure 1 in Do extraordinarily high growth rates in Permo-Triassic dicynodonts (Therapsida, Anomodontia) explain their success before and after the end-Permian extinction?

Figure 1. Stratigraphical ranges of the anomodonts used in this study. Modified from Angielczyk & Kurkin (2003) and Angielczyk & Walsh (2008). Oudenodon range updated from Botha & Angielczyk (2007). Kingoria is now referred to as Dicynodontoides following Angielczyk et al. (2009). Vertical solid bars and open bars indicate ranges and ghost lineages, respectively. Abbreviations: Chsn, Changhsingian; Ciste., Cistecephalus Assemblage Zone; Eodicyn., Eodicynodon Assemblage Zone; Ind., Induan; Lystro., Lystrosaurus; Olen., Olenekian; Prist., Pristerognathus Assemblage Zone; PTB, Permo-Triassic boundary; Tap., Tapinocephalus Assemblage Zone; Tropid. Tropidostoma Assemblage Zone; Wn, Wordian. Numbers indicate million years ago. Stratigraphical chart follows Catuneanu et al. (2005).

opennotspecifiedJul 2010View details →

Figure 4. Permo-Triassic dicynodont bone histology. A in Do extraordinarily high growth rates in Permo-Triassic dicynodonts (Therapsida, Anomodontia) explain their success before and after the end-Permian extinction?

Figure 4. Permo-Triassic dicynodont bone histology. A, juvenile Dicynodon humerus SAM-PK-K5576d; B, subadult Dicynodon humerus NMQR3633a; C, subadult Lystrosaurus maccaigi ulna NMQR3663b; D, juvenile Lystrosaurus declivis tibia NMQR735b; D, E, adult Lystrosaurus humerus (possibly Lystrosaurus declivis) NMQR3678; F, late subadult Kannemeyeria femur NMQR2674b. Arrows indicate enlarged channels in all genera. Scale bars: D, E = 500 mm; A, B, C, F = 413 mm.