scholarly journals Short- and long-term conditioning of a temperate marine diatom community to acidification and warming

2013 ◽  
Vol 368 (1627) ◽  
pp. 20120437 ◽  
Author(s):  
Avery O. Tatters ◽  
Michael Y. Roleda ◽  
Astrid Schnetzer ◽  
Feixue Fu ◽  
Catriona L. Hurd ◽  
...  
Keyword(s):  
Community Structure ◽  
Global Change ◽  
Interspecific Interactions ◽  
Interactive Effects ◽  
Marine Diatom ◽  
Diatom Community ◽  
Natural Community ◽  
Short Term ◽  
Natural Assemblage

Ocean acidification and greenhouse warming will interactively influence competitive success of key phytoplankton groups such as diatoms, but how long-term responses to global change will affect community structure is unknown. We incubated a mixed natural diatom community from coastal New Zealand waters in a short-term (two-week) incubation experiment using a factorial matrix of warming and/or elevated p CO 2 and measured effects on community structure. We then isolated the dominant diatoms in clonal cultures and conditioned them for 1 year under the same temperature and p CO 2 conditions from which they were isolated, in order to allow for extended selection or acclimation by these abiotic environmental change factors in the absence of interspecific interactions. These conditioned isolates were then recombined into ‘artificial’ communities modelled after the original natural assemblage and allowed to compete under conditions identical to those in the short-term natural community experiment. In general, the resulting structure of both the unconditioned natural community and conditioned ‘artificial’ community experiments was similar, despite differences such as the loss of two species in the latter. p CO 2 and temperature had both individual and interactive effects on community structure, but temperature was more influential, as warming significantly reduced species richness. In this case, our short-term manipulative experiment with a mixed natural assemblage spanning weeks served as a reasonable proxy to predict the effects of global change forcing on diatom community structure after the component species were conditioned in isolation over an extended timescale. Future studies will be required to assess whether or not this is also the case for other types of algal communities from other marine regimes.

The Biology of the Ground Parrot, Pezoporus wallicus, in Queensland. III. Distribution and Abundance

1991 ◽  
Vol 18 (2) ◽  
pp. 199 ◽  
Author(s):  
DC McFarland
Keyword(s):  
National Park ◽  
Historical Data ◽  
Vegetation Type ◽  
Habitat Destruction ◽  
Interactive Effects ◽  
Seasonal Effects ◽  
Short Term ◽  
The West ◽  
Seed Availability

Ground parrots in Queensland were found in closed graminoid-heathlands and sedgelands between Maryborough and Coolum on the mainland, and along the west coast of Fraser I. Parrot distribution, when compared to historical data, shows a decline which is a result of habitat destruction or degradation in the northern and southern limits of the species range. The current population is estimated at 2900 birds, with the majority in the heathlands of Cooloola National Park, Wide Bay Military Reserve and the State Forest and the Great Sandy National Park on Fraser I. Ground parrot density varied between sites because of the interactive effects of vegetation type, heathland area, time since and frequency of fire, microhabitat diversity and proximity to recolonisers. Within sites, parrot numbers changed in the long term with time since fire (influence of temporal changes in vegetation structure and seed availability) peaking at 5-8 years after burning, and in the short term with the seasonal effects of dispersal and breeding. Although predators were present their impact on the main populations was considered minimal. All of these factors are, to some extent, influenced by human activities, e.g. clearing and burning of heathlands.

scholarly journals Long-term effects of warming and ocean acidification are modified by seasonal variation in species responses and environmental conditions

2013 ◽  
Vol 368 (1627) ◽  
pp. 20130186 ◽  
Author(s):  
Jasmin A. Godbold ◽  
Martin Solan
Keyword(s):  
Seasonal Variation ◽  
Ocean Acidification ◽  
Environmental Conditions ◽  
Nutrient Release ◽  
Interactive Effects ◽  
Long Term Effects ◽  
Short Term ◽  
Climatic Forcing ◽  
Species Responses

Warming of sea surface temperatures and alteration of ocean chemistry associated with anthropogenic increases in atmospheric carbon dioxide will have profound consequences for a broad range of species, but the potential for seasonal variation to modify species and ecosystem responses to these stressors has received little attention. Here, using the longest experiment to date (542 days), we investigate how the interactive effects of warming and ocean acidification affect the growth, behaviour and associated levels of ecosystem functioning (nutrient release) for a functionally important non-calcifying intertidal polychaete ( Alitta virens ) under seasonally changing conditions. We find that the effects of warming, ocean acidification and their interactions are not detectable in the short term, but manifest over time through changes in growth, bioturbation and bioirrigation behaviour that, in turn, affect nutrient generation. These changes are intimately linked to species responses to seasonal variations in environmental conditions (temperature and photoperiod) that, depending upon timing, can either exacerbate or buffer the long-term directional effects of climatic forcing. Taken together, our observations caution against over emphasizing the conclusions from short-term experiments and highlight the necessity to consider the temporal expression of complex system dynamics established over appropriate timescales when forecasting the likely ecological consequences of climatic forcing.

scholarly journals Long-Term m5C Methylome Dynamics Parallel Phenotypic Adaptation in the Cyanobacterium Trichodesmium

2020 ◽  
Author(s):  
Nathan G Walworth ◽  
Michael D Lee ◽  
Egor Dolzhenko ◽  
Fei-Xue Fu ◽  
Andrew D Smith ◽  
...  
Keyword(s):  
Global Change ◽  
Co2 Concentration ◽  
Adaptive Responses ◽  
Short Term ◽  
Modern Biology ◽  
High Co2 ◽  
Biological Responses ◽  
Evolution Experiment ◽  
Ambient Co2

Abstract A major challenge in modern biology is understanding how the effects of short-term biological responses influence long-term evolutionary adaptation, defined as a genetically determined increase in fitness to novel environments. This is particularly important in globally important microbes experiencing rapid global change, due to their influence on food webs, biogeochemical cycles, and climate. Epigenetic modifications like methylation have been demonstrated to influence short-term plastic responses, which ultimately impact long-term adaptive responses to environmental change. However, there remains a paucity of empirical research examining long-term methylation dynamics during environmental adaptation in nonmodel, ecologically important microbes. Here, we show the first empirical evidence in a marine prokaryote for long-term m5C methylome modifications correlated with phenotypic adaptation to CO2, using a 7-year evolution experiment (1,000+ generations) with the biogeochemically important marine cyanobacterium Trichodesmium. We identify m5C methylated sites that rapidly changed in response to high (750 µatm) CO2 exposure and were maintained for at least 4.5 years of CO2 selection. After 7 years of CO2 selection, however, m5C methylation levels that initially responded to high-CO2 returned to ancestral, ambient CO2 levels. Concurrently, high-CO2 adapted growth and N2 fixation rates remained significantly higher than those of ambient CO2 adapted cell lines irrespective of CO2 concentration, a trend consistent with genetic assimilation theory. These data demonstrate the maintenance of CO2-responsive m5C methylation for 4.5 years alongside phenotypic adaptation before returning to ancestral methylation levels. These observations in a globally distributed marine prokaryote provide critical evolutionary insights into biogeochemically important traits under global change.

scholarly journals Impacts of nitrogen addition on switchgrass root-associated diazotrophic community structure and function

2020 ◽  
Vol 96 (12) ◽  
Author(s):  
Darian N Smercina ◽  
Sarah E Evans ◽  
Maren L Friesen ◽  
Lisa K Tiemann
Keyword(s):  
Community Structure ◽  
Panicum Virgatum ◽  
Agricultural Practices ◽  
Bioenergy Crops ◽  
Climate Mitigation ◽  
N Addition ◽  
Short Term ◽  
And Function ◽  
Diazotrophic Community

ABSTRACT Cellulosic bioenergy crops, like switchgrass (Panicum virgatum), have potential for growth on lands unsuitable for food production coupled with potential for climate mitigation. Sustainability of these systems lies in identifying conditions that promote high biomass yields on marginal lands under low-input agricultural practices. Associative nitrogen fixation (ANF) is a potentially important nitrogen (N) source for these crops, yet ANF contributions to plant N, especially under fertilizer N addition are unclear. In this study, we assess structure (nifH) and function (ANF) of switchgrass root-associated diazotrophic communities to long-term and short-term N additions using soil from three marginal land sites. ANF rates were variable and often unexpectedly high, sometimes 10× greater than reported in the literature, and did not respond in repeatable ways to long-term or short-term N. We found few impacts of N addition on root-associated diazotrophic community structure or membership. Instead, we found a very consistent root-associated diazotrophic community even though switchgrass seeds were germinated in soil from field sites with distinct diazotrophic communities. Ultimately, this work demonstrates that root-associated diazotrophic communities have the potential to contribute to switchgrass N demands, independent of N addition, and this may be driven by selection of the diazotrophic community by switchgrass roots.

scholarly journals Lipid Remodeling Reveals the Adaptations of a Marine Diatom to Ocean Acidification

2021 ◽  
Vol 12 ◽  
Author(s):  
Peng Jin ◽  
Zhe Liang ◽  
Hua Lu ◽  
Jinmei Pan ◽  
Peiyuan Li ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Phaeodactylum Tricornutum ◽  
Adaptation Strategy ◽  
Trophic Levels ◽  
Marine Diatom ◽  
Short Term ◽  
Tightly Coupled ◽  
Marine Food ◽  
Lipid Metabolites

Ocean acidification is recognized as a major anthropogenic perturbation of the modern ocean. While extensive studies have been carried out to explore the short-term physiological responses of phytoplankton to ocean acidification, little is known about their lipidomic responses after a long-term ocean acidification adaptation. Here we perform the lipidomic analysis of a marine diatom Phaeodactylum tricornutum following long-term (∼400 days) selection to ocean acidification conditions. We identified a total of 476 lipid metabolites in long-term high CO2 (i.e., ocean acidification condition) and low CO2 (i.e., ambient condition) selected P. tricornutum cells. Our results further show that long-term high CO2 selection triggered substantial changes in lipid metabolites by down- and up-regulating 33 and 42 lipid metabolites. While monogalactosyldiacylglycerol (MGDG) was significantly down-regulated in the long-term high CO2 selected conditions, the majority (∼80%) of phosphatidylglycerol (PG) was up-regulated. The tightly coupled regulations (positively or negatively correlated) of significantly regulated lipid metabolites suggest that the lipid remodeling is an organismal adaptation strategy of marine diatoms to ongoing ocean acidification. Since the composition and content of lipids are crucial for marine food quality, and these changes can be transferred to high trophic levels, our results highlight the importance of determining the long-term adaptation of lipids in marine producers in predicting the ecological consequences of climate change.

Influence of Deforestation on the Community Structure of Sand Flies (Diptera: Psychodidae) in Eastern Amazonia

2019 ◽  
Vol 56 (4) ◽  
pp. 1004-1012
Author(s):  
José Manuel Macário Rebêlo ◽  
Jorge Luiz Pinto Moraes ◽  
Gustavo Barbosa Vieira Cruz ◽  
Joudellys Andrade-Silva ◽  
Maria Da Conceição Abreu Bandeira ◽  
...  
Keyword(s):  
Community Structure ◽  
Species Composition ◽  
Significant Influence ◽  
Sand Fly ◽  
Forest Fragments ◽  
Sand Flies ◽  
Human Occupation ◽  
Short Term

Abstract Variation in the structure of phlebotomine (sand fly) communities in forest fragments with different degrees of preservation and human occupation (peridomicile) in eastern Amazonia was studied. We identified 43 species of sand flies in our study, of which 38 occurred in both preserved forest areas and in the peridomiciles of short-term settlements, while another 28 species occurred in altered forest fragments and long-term settlements. The composition of the community at each site changed with the type of environment (forest or peridomicile), with the species Lutzomyia evandroi, L. whitmani, L. choti, L. serrana, L. triacantha, L. migonei, L. hirsuta, L. shannoni, and L. brachyphylla accounting for more than 54% of the differences among environments. The quality of the environment exerted a significant influence on the structure of phlebotomine communities, and affected their species composition, richness, and abundance.

scholarly journals The Effect of Perfluorooctane Sulfonate, Exposure Time, and Chemical Mixtures on Methanogenic Community Structure and Function

2015 ◽  
Vol 8s2 ◽  
pp. MBI.S31345 ◽  
Author(s):  
Patrick J. McNamara ◽  
Timothy M. LaPara ◽  
Paige J. Novak
Keyword(s):  
Community Structure ◽  
Exposure Time ◽  
Methane Production ◽  
Perfluorooctane Sulfonate ◽  
Structure And Function ◽  
Short Term ◽  
Anaerobic Digesters ◽  
And Function ◽  
The Impact

A plethora of organic micropollutant mixtures are found in untreated municipal wastewater. Anaerobic digesters receive large loadings of hydrophobic micropollutants that sorb to wastewater biosolids. Despite micropollutants being pervasive as mixtures, little research is available to explain the impact that mixtures of compounds, as well as exposure time, have on microbial communities in anaerobic digesters. Perfluorooctane sulfonate (PFOS) was added to anaerobic enrichment cultures in both short-term (14 days) and long-term (140 days) studies to determine the impact of exposure time. Additionally, triclosan was added during the experiments to investigate the impact of mixtures on community structure and function. PFOS did not alter methane production in short-term studies, but in long-term studies, methane production increased, consistent with our hypothesis that PFOS may act as a metabolic uncoupler. The impact of triclosan on methane production was exacerbated when PFOS was already present in the anaerobic enrichment cultures. Triclosan also had greater impacts on microbial community structures in the bottles that had been exposed to PFOS long-term. These results demonstrate that both chemical mixtures and exposure time are important parameters to address when trying to define the impacts of micropollutants on anaerobic microbial communities.

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