Growth rates of natural populations of marine diatoms as determined in cage cultures

1984 ◽  
pp. 113-127
Author(s):  
G. A. Vargo
Keyword(s):  
Growth Rates ◽  
Natural Populations ◽  
Marine Diatoms

Hybridization in leopard frogs (Rana pipiens complex): terrestrial performance of newly metamorphosed hybrid and parental genotypes in field enclosures

2001 ◽  
Vol 79 (9) ◽  
pp. 1552-1558 ◽  
Author(s):  
Matthew J Parris
Keyword(s):  
Growth Rates ◽  
Life Histories ◽  
Parental Species ◽  
Natural Populations ◽  
Life Cycles ◽  
Natural Hybridization ◽  
Evolutionary Potential ◽  
Leopard Frogs ◽  
Rana Blairi ◽  
Advanced Generation

Terrestrial ecology has been largely neglected in the study of amphibian life histories because it is difficult to manipulate most species during the terrestrial stage. I examined the terrestrial performance of Rana blairi, Rana sphenocephala, and four hybrid (two F1 and two advanced generation) genotypes in replicated experimental enclosures to test for differences in traits related to juvenile terrestrial fitness. I produced all genotypes by means of artificial fertilizations using frogs collected from natural populations in central Missouri, and juvenile frogs were obtained from larvae reared in experimental ponds. Following metamorphosis, froglets were raised in single-genotype groups in terrestrial enclosures through the first overwintering. The proportion surviving did not vary among genotypes, but the power to detect significant differences was low. F1 hybrid genotypes BS and SB demonstrated significantly higher growth rates than either parental species or advanced-generation hybrid genotypes. Observation of growth rates of advanced-generation hybrids equal to those of the parental species, and heterosis in F1 hybrids for growth rate, suggests that natural hybridization between R. blairi and R. sphenocephala can produce novel and relatively fit hybrid genotypes. Direct measurement of multiple fitness components for hybrid and parental genotypes is critical for assessing the evolutionary potential of natural hybridization in organisms with complex life cycles.

Sex expression and growth rates in natural populations of the desert soil crustal mossSyntrichia caninervis

1998 ◽  
Vol 40 (4) ◽  
pp. 401-416 ◽  
Author(s):  
Lloyd R. Stark ◽  
Brent D. Mishler ◽  
D.Nicholas McLetchie
Keyword(s):  
Growth Rates ◽  
Natural Populations ◽  
Sex Expression ◽  
Desert Soil

Growth dynamics in natural populations of Sphaeriidae clams (Sphaerium, Musculium, Pisidium)

1979 ◽  
Vol 57 (2) ◽  
pp. 441-456 ◽  
Author(s):  
G. L. Mackie
Keyword(s):  
Growth Rates ◽  
Larval Growth ◽  
Natural Populations ◽  
Growth Dynamics ◽  
Logarithmic Phase ◽  
River Population ◽  
Small Litter ◽  
Larval Stages ◽  
Permanent Pond ◽  
Accelerated Growth

Analyses of life history samples of five species of sphaeriid clams collected at least monthly for 1 year from 10 different habitats show that growth of all larval stages stops when parents cease to grow. During the logarithmic phase of growth larvae grow slower than parents in temporary and permanent pond populations of Musculium lacustre, Pisidium casertanum, and Pisidium variabile, as fast as parents in a river population of Sphaerium fabale, and as fast or faster than parents in five populations of Musculium securis. Species with slow larval growth rates are usually semelparous and univoltine but can be iteroparous by precocious birth of larvae and multivoltine by accelerated growth of semelparous individuals. Species with rapid larval growth rates are usually iteroparous because larvae grow faster than parents and (or) there is precocious birth of larvae. There is greater mortality of larvae during early stages than during later stages of larval development. The greatest numbers of larvae per parent usually occur in early winter and (or) late spring; winter and summer 'kills' often result in small litter sizes.

scholarly journals Carbon Dioxide Concentration Mechanisms in Natural Populations of Marine Diatoms: Insights From Tara Oceans

2021 ◽  
Vol 12 ◽  
Author(s):  
Juan José Pierella Karlusich ◽  
Chris Bowler ◽  
Haimanti Biswas
Keyword(s):  
Phosphoenolpyruvate Carboxykinase ◽  
Environmental Variability ◽  
Natural Populations ◽  
Size Fraction ◽  
Carbon Dioxide Concentration ◽  
Molecular Data ◽  
Rubisco Activase ◽  
Nutrient Concentrations ◽  
Marine Diatoms ◽  
Environmental Correlations

Marine diatoms, the most successful photoautotrophs in the ocean, efficiently sequester a significant part of atmospheric CO2 to the ocean interior through their participation in the biological carbon pump. However, it is poorly understood how marine diatoms fix such a considerable amount of CO2, which is vital information toward modeling their response to future CO2 levels. The Tara Oceans expeditions generated molecular data coupled with in situ biogeochemical measurements across the main ocean regions, and thus provides a framework to compare diatom genetic and transcriptional flexibility under natural CO2 variability. The current study investigates the interlink between the environmental variability of CO2 and other physicochemical parameters with the gene and transcript copy numbers of five key enzymes of diatom CO2 concentration mechanisms (CCMs): Rubisco activase and carbonic anhydrase (CA) as part of the physical pathway, together with phosphoenolpyruvate carboxylase, phosphoenolpyruvate carboxykinase, and malic enzyme as part of the potential C4 biochemical pathway. Toward this aim, we mined >200 metagenomes and >220 metatranscriptomes generated from samples of the surface layer of 66 globally distributed sampling sites and corresponding to the four main size fractions in which diatoms can be found: 0.8–5 μm, 5–20 μm, 20–180 μm, and 180–2,000 μm. Our analyses revealed that the transcripts for the enzymes of the putative C4 biochemical CCM did not in general display co-occurring profiles. The transcripts for CAs were the most abundant, with an order of magnitude higher values than the other enzymes, thus implying the importance of physical CCMs in diatom natural communities. Among the different classes of this enzyme, the most prevalent was the recently characterized iota class. Consequently, very little information is available from natural diatom assemblages about the distribution of this class. Biogeographic distributions for all the enzymes show different abundance hotspots according to the size fraction, pointing to the influence of cell size and aggregation in CCMs. Environmental correlations showed a complex pattern of responses to CO2 levels, total phytoplankton biomass, temperature, and nutrient concentrations. In conclusion, we propose that biophysical CCMs are prevalent in natural diatom communities.

Field validation of an instantaneous estimate of in situ development and growth for marine copepod communities

2006 ◽  
Vol 63 (12) ◽  
pp. 2639-2647 ◽  
Author(s):  
Akash R Sastri ◽  
John F Dower
Keyword(s):  
Growth Rates ◽  
Natural Populations ◽  
Field Validation ◽  
Marine Copepod ◽  
Marine Zooplankton ◽  
Coastal British Columbia ◽  
Individual Body ◽  
Good Agreement ◽  
Marine Copepods

To date, efforts to develop a method for rapidly measuring the development and growth rates of marine zooplankton have met with little success. In recent years, however, a simple assay based on a crustacean moulting enzyme, chitobiase, has shown considerable promise. Previous laboratory studies have demonstrated that chitobiase activity is proportional to individual body size across three species of freshwater daphnids. Here, we show that a significant positive relationship exists between chitobiase activity and body length (and weight) across four species of marine copepods collected from natural populations in coastal British Columbia, Canada. We measured the decay rate of chitobiase in the water column and estimated in situ moulting and growth rates of the entire copepod community, which are in good agreement (5%–15%) with conventional moulting rates and literature-based estimates. This method can be applied at a relatively high spatial and temporal resolution and its utility is potentially analogous to conventional community-wide productivity estimates for phytoplankton and bacterioplankton in marine and freshwater systems.

scholarly journals Benchmarking microbial growth rate predictions from metagenomes

2020 ◽  
Vol 15 (1) ◽  
pp. 183-195
Author(s):  
Andrew M. Long ◽  
Shengwei Hou ◽  
J. Cesar Ignacio-Espinoza ◽  
Jed A. Fuhrman
Keyword(s):  
Growth Rates ◽  
Microbial Growth ◽  
Community Dynamics ◽  
Natural Populations ◽  
Maximum Growth ◽  
Microbial Interactions ◽  
Bacterial Populations ◽  
Pure Cultures ◽  
Actual Growth

AbstractGrowth rates are central to understanding microbial interactions and community dynamics. Metagenomic growth estimators have been developed, specifically codon usage bias (CUB) for maximum growth rates and “peak-to-trough ratio” (PTR) for in situ rates. Both were originally tested with pure cultures, but natural populations are more heterogeneous, especially in individual cell histories pertinent to PTR. To test these methods, we compared predictors with observed growth rates of freshly collected marine prokaryotes in unamended seawater. We prefiltered and diluted samples to remove grazers and greatly reduce virus infection, so net growth approximated gross growth. We sampled over 44 h for abundances and metagenomes, generating 101 metagenome-assembled genomes (MAGs), including Actinobacteria, Verrucomicrobia, SAR406, MGII archaea, etc. We tracked each MAG population by cell-abundance-normalized read recruitment, finding growth rates of 0 to 5.99 per day, the first reported rates for several groups, and used these rates as benchmarks. PTR, calculated by three methods, rarely correlated to growth (r ~−0.26–0.08), except for rapidly growing γ-Proteobacteria (r ~0.63–0.92), while CUB correlated moderately well to observed maximum growth rates (r = 0.57). This suggests that current PTR approaches poorly predict actual growth of most marine bacterial populations, but maximum growth rates can be approximated from genomic characteristics.

scholarly journals Conflicting functional effects of xylem pit structure relate to the growth-longevity trade-off in a conifer species

2019 ◽  
Vol 116 (30) ◽  
pp. 15282-15287 ◽  
Author(s):  
Beth Roskilly ◽  
Eric Keeling ◽  
Sharon Hood ◽  
Arnaud Giuggiola ◽  
Anna Sala
Keyword(s):  
Life History ◽  
Pinus Ponderosa ◽  
Growth Rates ◽  
Morphological Traits ◽  
Natural Populations ◽  
Negative Relationship ◽  
Multiple Traits ◽  
Conifer Species ◽  
Trade Off ◽  
Trade Offs

Consistent with a ubiquitous life history trade-off, trees exhibit a negative relationship between growth and longevity both among and within species. However, the mechanistic basis of this life history trade-off is not well understood. In addition to resource allocation conflicts among multiple traits, functional conflicts arising from individual morphological traits may also contribute to life history trade-offs. We hypothesized that conflicting functional effects of xylem structural traits contribute to the growth-longevity trade-off in trees. We tested this hypothesis by examining the extent to which xylem morphological traits (i.e., wood density, tracheid diameters, and pit structure) relate to growth rates and longevity in two natural populations of the conifer speciesPinus ponderosa. Hydraulic constraints arise as trees grow larger and xylem anatomical traits adjust to compensate. We disentangled the effects of size through ontogeny in individual trees and growth rates among trees on xylem traits by sampling each tree at multiple trunk diameters. We found that the oldest trees had slower lifetime growth rates compared with younger trees in the studied populations, indicating a growth-longevity trade-off. We further provide evidence that a single xylem trait, pit structure, with conflicting effects on xylem function (hydraulic safety and efficiency) relates to the growth-longevity trade-off in a conifer species. This study highlights that, in addition to trade-offs among multiple traits, functional constraints based on individual morphological traits like that of pit structure provide mechanistic insight into how and when life history trade-offs arise.

scholarly journals Revisiting Connell: competition but not as we know it

2017 ◽  
Vol 98 (6) ◽  
pp. 1253-1261 ◽  
Author(s):  
Jenna M. Gordon ◽  
Antony M. Knights
Keyword(s):  
Growth Rates ◽  
Natural Populations ◽  
Small Scale ◽  
Nearest Neighbour ◽  
Negative Effects ◽  
Lower Growth ◽  
Neighbour Distance ◽  
Lower Growth Rate ◽  
Pair Competition ◽  
Reduced Density

Space is one of the primary limiting resources for organisms on the intertidal rocky shore. This paper examined the effect of reduced density on key traits (mortality and growth) on the intertidal barnacles, Chthamalus montagui and Semibalanus balanoides, on the mid-shore in Plymouth, UK. Intra- and interspecific treatments comprising of C. montagui and S. balanoides were manipulated to reduce densities at two similar sites. Changes in mortality and operculum growth were assessed over an 8-week period using digital photography. Covariates of growth included nearest neighbour distance, competition between closest pairs and initial size. Conflicting patterns were observed when comparing growth rates between treatments and sites. At Site 1, interspecific treatments had a lower growth rate than intraspecific treatments, whereas at Site 2, interspecific growth rates were higher. ANCOVA showed that nearest neighbour distance had no significant effect on growth, but when comparing differences in growth of closest neighbouring pairs, C. montagui treatment showed evidence of competition whereas S. balanoides did not. ANCOVA analysis indicated no difference in growth between each outcome of pair competition, suggesting winners are initially bigger than losers. Comparisons of mortality between treatments indicated mortality over time with no significant differences observed between treatments, but response surface methodology (RSM) revealed no effects of competition on mortality of S. balanoides, but negative effects of both intra- and interspecific competition on C. montagui survivorship. Examination of natural populations of barnacles in the mid-shore indicated there was strong spatial variation in growth rates, perhaps driven by small-scale differences within sites.

Sign in / Sign up

Export Citation Format

Share Document