Current and Historical Resource Nitrogen Supply Affects the Eco-Physiological Traits and the Ionome of a Diazotrophic Cyanobacterium.

Diazotrophic cyanobacteria can overcome nitrogen (N)-limitation by fixing atmospheric N; however, this increases their energetic, iron, molybdenum, and boron costs. It is unknown how current and historic N-supplies affect cyanobacterial elemental physiology beyond increasing demands for elements involved in N-fixation. Here, we examined the changes in pigment concentrations, N-storage, and the ionome (i.

Spatiotemporal Variation in Dissolved, Bioavailable, and Particulate Elements and the Abundance of Harmful Algae in Grand Lake.

Harmful algal blooms (HABs) are often linked to the increased loading of limiting nutrients such as nitrogen and phosphorus. Little is known about the relevance of other biogenic elements, the supplies of which are spatiotemporally heterogeneous, on HABs. We measured the dissolved, bioavailable, and particulate concentrations of 26 elements at four locations draining different catchments of a large reservoir during three seasons, in addition to the total abundance of phytoplankton and % of cyanobacteria.

Understanding stoichiometric constraints on growth using resource use efficiency imbalances.

Growth is a function of the net accrual of resources by an organism. Energy and elemental contents of organisms are dynamically linked through their uptake and allocation to biomass production, yet we lack a full understanding of how these dynamics regulate growth rate. Here, we develop a multivariate imbalance framework, the growth efficiency hypothesis, linking organismal resource contents to growth and metabolic use efficiencies, and demonstrate its effectiveness in predicting consumer growth rates under elemental and food quantity limitation.

SEED: A framework for integrating ecological stoichiometry and eco-evolutionary dynamics.

Characterising the extent and sources of intraspecific variation and their ecological consequences is a central challenge in the study of eco-evolutionary dynamics. Ecological stoichiometry, which uses elemental variation of organisms and their environment to understand ecosystem patterns and processes, can be a powerful framework for characterising eco-evolutionary dynamics. However, the current emphasis on the relative content of elements in the body (i.

Adaptation to a limiting element involves mitigation of multiple elemental imbalances.

About 20 elements underlie biology and thus constrain biomass production. Recent systems-level observations indicate that altered supply of one element impacts the processing of most elements encompassing an organism (i.e.

Revisiting the growth rate hypothesis: Towards a holistic stoichiometric understanding of growth.

The growth rate hypothesis (GRH) posits that variation in organismal stoichiometry (C:P and N:P ratios) is driven by growth-dependent allocation of P to ribosomal RNA. The GRH has found broad but not uniform support in studies across diverse biota and habitats. We synthesise information on how and why the tripartite growth-RNA-P relationship predicted by the GRH may be uncoupled and outline paths for both theoretical and empirical work needed to broaden the working domain of the GRH.

The roles of recombination and selection in shaping genomic divergence in an incipient ecological species complex.

Speciation genomic studies have revealed that genomes of diverging lineages are shaped jointly by the actions of gene flow and selection. These evolutionary forces acting in concert with processes such as recombination and genome features such as gene density shape a mosaic landscape of divergence. We investigated the roles of recombination and gene density in shaping the patterns of differentiation and divergence between the cyclically parthenogenetic ecological sister-taxa, Daphnia pulicaria and Daphnia pulex.

Impacts of heavy metal pollution on the ionomes and transcriptomes of Western mosquitofish (Gambusia affinis).

Our understanding of the mechanisms mediating the resilience of organisms to environmental change remains lacking. Heavy metals negatively affect processes at all biological scales, yet organisms inhabiting contaminated environments must maintain homeostasis to survive. Tar Creek in Oklahoma, USA, contains high concentrations of heavy metals and an abundance of Western mosquitofish (Gambusia affinis), though several fish species persist at lower frequency.

Growth and ionomic responses of a freshwater cyanobacterium to supplies of nitrogen and iron.

Cyanobacterial harmful algal blooms (HABs) are increasing in frequency and magnitude worldwide. A number of parameters are thought to underlie HABs, including the ratio at which two key elements, nitrogen (N) and phosphorus (P) are supplied, although a predictive understanding eludes us. While the physiological importance of iron (Fe) in electron transport and N-fixation is well known, relatively little is known about its impacts on the growth of freshwater cyanobacteria.

Quantitative genetics of phosphorus content in the freshwater herbivore, Daphnia pulicaria.

Phosphorus (P) is essential for growth of all organisms, and P content is correlated with growth in most taxa. Although P content was initially considered to be a trait fixed at the species level, there is growing evidence for considerable intraspecific variation. Selection on such variation can thus alter the rates at which P fluxes through food webs.

Differential responses of macroinvertebrate ionomes across experimental N:P gradients in detritus-based headwater streams.

Diverse global change processes are reshaping the biogeochemistry of stream ecosystems. Nutrient enrichment is a common stressor that can modify flows of biologically important elements such as carbon (C), nitrogen (N), and phosphorus (P) through stream foodwebs by altering the stoichiometric composition of stream organisms. However, enrichment effects on concentrations of other important essential and trace elements in stream taxa are less understood.

Phosphorus supply shifts the quotas of multiple elements in algae and Daphnia: ionomic basis of stoichiometric constraints.

The growth rate hypothesis posits that the rate of protein synthesis is constrained by phosphorus (P) supply. P scarcity invokes differential expression of genes involved in processing of most if not all elements encompassing an individual (the ionome). Whether such ionome-wide adjustments to P supply impact growth and trophic interactions remains unclear.

Does differential iron supply to algae affect Daphnia life history? An ionome-wide study.

The availability of iron (Fe) varies considerably among diet items, as well as ecosystems. Availability of Fe has also changed due to anthropogenic environmental changes in oceanic as well as inland ecosystems. We know little about its role in the nutrition of ecologically important consumers, particularly in inland ecosystems.

Ionome and elemental transport kinetics shaped by parallel evolution in threespine stickleback.

Evidence that organisms evolve rapidly enough to alter ecological dynamics necessitates investigation of the reciprocal links between ecology and evolution. Data that link genotype to phenotype to ecology are needed to understand both the process and ecological consequences of rapid evolution. Here, we quantified the suite of elements in individuals (i.

Resurrected 'ancient' genotypes show reduced thermal stress tolerance compared to modern descendants.

Understanding how populations adapt to rising temperatures has been a challenge in ecology. Research often evaluates multiple populations to test whether local adaptation to temperature regimes is occurring. Space-for-time substitutions are common, as temporal constraints limit our ability to observe evolutionary responses.

Genotype-specific relationships among phosphorus use, growth and abundance in .

The framework ecological stoichiometry uses elemental composition of species to make predictions about growth and competitive ability in defined elemental supply conditions. Although intraspecific differences in stoichiometry have been observed, we have yet to understand the mechanisms generating and maintaining such variation. We used variation in phosphorus (P) content within a species to test the extent to which %P can explain variation in growth and competition.

Evolutionary aspects of resurrection ecology: Progress, scope, and applications-An overview.

This perspective provides an overview to the Special Issue on Resurrection Ecology (RE). It summarizes the contributions to this Special Issue, and provides background information and future prospects for the use of RE in both basic and applied evolutionary studies.

Assessment of biochemical mechanisms of tolerance to chlorpyrifos in ancient and contemporary Daphnia pulicaria genotypes.

The evolution of tolerance to environmental contaminants in non-target taxa has been largely studied by comparing extant populations experiencing contrasting exposure. Previous research has demonstrated that "resurrected" genotypes from a population of Daphnia pulicaria express temporal variation in sensitivity to the insecticide chlorpyrifos. Ancient genotypes (1301-1646AD.

Whole genome amplification and sequencing of a Daphnia resting egg.

Resting eggs banks are unique windows that allow us to directly observe shifts in population genetics, and phenotypes over time as natural populations evolve. Though a variety of planktonic organisms also produce resting stages, the keystone freshwater consumer, Daphnia, is a well-known model for paleogenetics and resurrection ecology. Nevertheless, paleogenomic investigations are limited largely because resting eggs do not contain enough DNA for genomic sequencing.

Ecological Stoichiometry beyond Redfield: An Ionomic Perspective on Elemental Homeostasis.

Elemental homeostasis has been largely characterized using three important elements that were part of the Redfield ratio (i.e., carbon: nitrogen: phosphorus).

Merging elemental and macronutrient approaches for a comprehensive study of energy and nutrient flows.

Global warming and predation risk can have important impacts on animal physiology and life histories that can have consequences for ecosystem function. Zhang et al. () recently tested the separate and interactive effects of warming and predation risk on the body composition of Daphnia magna.

Paleogenetic records of Daphnia pulicaria in two North American lakes reveal the impact of cultural eutrophication.

Understanding the evolutionary consequences of the green revolution, particularly in wild populations, is an important frontier in contemporary biology. Because human impacts have occurred at varying magnitudes or time periods depending on the study ecosystem, evolutionary histories may vary considerably among populations. Paleogenetics in conjunction with paleolimnology enable us to associate microevolutionary dynamics with detailed information on environmental change.

Sex-specific nutrient use and preferential allocation of resources to a sexually selected trait in Hyalella amphipods.

Although sexually dimorphic traits are often well studied, we know little about sex-specific resource use strategies that should underlie such dimorphism. We measured sex-specific responses in acquisition and assimilation of two fundamental resources, carbon (C) and phosphorus (P) in juvenile and mature Hyalella amphipods given low and high supplies of inorganic phosphate, analogous to oligotrophic and eutrophic conditions, respectively. Additionally, we quantified allocation of resources to sexual traits in males.

Endopolyploidy as a potential driver of animal ecology and evolution.

Endopolyploidy - the existence of higher-ploidy cells within organisms that are otherwise of a lower ploidy level (generally diploid) - was discovered decades ago, but remains poorly studied relative to other genomic phenomena, especially in animals. Our synthetic review suggests that endopolyploidy is more common in animals than often recognized and probably influences a number of fitness-related and ecologically important traits. In particular, we argue that endopolyploidy is likely to play a central role in key traits such as gene expression, body and cell size, and growth rate, and in a variety of cell types, including those responsible for tissue regeneration, nutrient storage, and inducible anti-predator defences.