The impact of abiotic factors on the growth and lipid accumulation of some green microalgae for sustainable biodiesel production

Protective legislation and management have led to an increase in California’s sea otter Enhydra lutris nereis population. While sea otter recovery has been linked to ecosystem benefits, sea otter predation may negatively affect commercially valuable species. Understanding the potential influence of sea otters is of particular importance as their range expands into estuaries that function as nurseries for commercially valuable species like Dungeness crab Metacarcinus magister. We consider how sea otter predation has affected the abundance and size of juvenile Dungeness crab in Elkhorn Slough, California, USA, and analyzed cancrid crab abundance and size across 4 California estuaries with and without sea otters to understand how biotic and abiotic factors contribute to observed variation in crab size and abundance. We compared trends in southern sea otters relative to Dungeness crab landings in California to assess whether increasing sea otter abundance have negatively impacted landings. In Elkhorn Slough, juvenile Dungeness crab abundance and size have declined since 2012, coinciding with sea otter population growth. However, the impact of sea otters on juvenile Dungeness crab size was habitat-specific and only significant in unvegetated habitat. Across estuaries, we found that cancrid crab abundance and size were negatively associated with sea otter presence. While abiotic factors varied among estuaries, these factors explained little of the observed variation in crab abundance or size. Although we found evidence that sea otters can have localized effects on cancrid crab populations within estuaries, we found no evidence that southern sea otters, at recent population sizes, have negatively impacted Dungeness crab landings in California from 2000-2014.

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Parasitism of Aedes albopictus by Ascogregarina taiwanensis lowers its competitive ability against Aedes triseriatus

Parasites & Vectors ◽

10.1186/s13071-021-04581-0 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Emma Stump ◽

Lauren M. Childs ◽

Melody Walker

Keyword(s):

Population Dynamics ◽

Competitive Advantage ◽

Aedes Albopictus ◽

Abiotic Factors ◽

Mosquito Species ◽

Disease Spread ◽

Aedes Triseriatus ◽

La Crosse Virus ◽

The Impact ◽

Ascogregarina Taiwanensis

Abstract Background Mosquitoes are vectors for diseases such as dengue, malaria and La Crosse virus that significantly impact the human population. When multiple mosquito species are present, the competition between species may alter population dynamics as well as disease spread. Two mosquito species, Aedes albopictus and Aedes triseriatus, both inhabit areas where La Crosse virus is found. Infection of Aedes albopictus by the parasite Ascogregarina taiwanensis and Aedes triseriatus by the parasite Ascogregarina barretti can decrease a mosquito’s fitness, respectively. In particular, the decrease in fitness of Aedes albopictus occurs through the impact of Ascogregarina taiwanensis on female fecundity, larval development rate, and larval mortality and may impact its initial competitive advantage over Aedes triseriatus during invasion. Methods We examine the effects of parasitism of gregarine parasites on Aedes albopictus and triseriatus population dynamics and competition with a focus on when Aedes albopictus is new to an area. We build a compartmental model including competition between Aedes albopictus and triseriatus while under parasitism of the gregarine parasites. Using parameters based on the literature, we simulate the dynamics and analyze the equilibrium population proportion of the two species. We consider the presence of both parasites and potential dilution effects. Results We show that increased levels of parasitism in Aedes albopictus will decrease the initial competitive advantage of the species over Aedes triseriatus and increase the survivorship of Aedes triseriatus. We find Aedes albopictus is better able to invade when there is more extreme parasitism of Aedes triseriatus. Furthermore, although the transient dynamics differ, dilution of the parasite density through uptake by both species does not alter the equilibrium population sizes of either species. Conclusions Mosquito population dynamics are affected by many factors, such as abiotic factors (e.g. temperature and humidity) and competition between mosquito species. This is especially true when multiple mosquito species are vying to live in the same area. Knowledge of how population dynamics are affected by gregarine parasites among competing species can inform future mosquito control efforts and help prevent the spread of vector-borne disease.

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Longitudinal sampling of external mucosae in farmed European seabass reveals the impact of water temperature on bacterial dynamics

ISME Communications ◽

10.1038/s43705-021-00019-x ◽

2021 ◽

Vol 1 (1) ◽

Author(s):

Daniela Rosado ◽

Raquel Xavier ◽

Jo Cable ◽

Ricardo Severino ◽

Pedro Tarroso ◽

...

Keyword(s):

Environmental Factors ◽

Microbial Diversity ◽

Water Temperature ◽

Abiotic Factors ◽

Seasonal Effect ◽

Microbial Composition ◽

Surrounding Water ◽

European Seabass ◽

And Function ◽

The Impact

AbstractFish microbiota are intrinsically linked to health and fitness, but they are highly variable and influenced by both biotic and abiotic factors. Water temperature particularly limits bacterial adhesion and growth, impacting microbial diversity and bacterial infections on the skin and gills. Aquaculture is heavily affected by infectious diseases, especially in warmer months, and industry practices often promote stress and microbial dysbiosis, leading to an increased abundance of potentially pathogenic bacteria. In this regard, fish mucosa health is extremely important because it provides a primary barrier against pathogens. We used 16 rRNA V4 metataxonomics to characterize the skin and gill microbiota of the European seabass, Dicentrarchus labrax, and the surrounding water over 12 months, assessing the impact of water temperature on microbial diversity and function. We show that the microbiota of external mucosae are highly dynamic with consistent longitudinal trends in taxon diversity. Several potentially pathogenic genera (Aliivibrio, Photobacterium, Pseudomonas, and Vibrio) were highly abundant, showing complex interactions with other bacterial genera, some of which with recognized probiotic activity, and were also significantly impacted by changes in temperature. The surrounding water temperature influenced fish microbial composition, structure and function over time (days and months). Additionally, dysbiosis was more frequent in warmer months and during transitions between cold/warm months. We also detected a strong seasonal effect in the fish microbiota, which is likely to result from the compound action of several unmeasured environmental factors (e.g., pH, nutrient availability) beyond temperature. Our results highlight the importance of performing longitudinal studies to assess the impact of environmental factors on fish microbiotas.

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Bestandesdynamik zentralalpiner Waldföhrenwälder aufgezeigt anhand dendroökologischer Fallstudien aus dem Wallis, Schweiz | Stand dynamics of central alpine Scots pine using dendroecological case studies from Valais, Switzerland

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2004.0178 ◽

2004 ◽

Vol 155 (6) ◽

pp. 178-190 ◽

Cited By ~ 11

Author(s):

Andreas Rigling ◽

Pascale Weber ◽

Paolo Cherubini ◽

Matthias Dobbertin

Keyword(s):

Case Studies ◽

Scots Pine ◽

Forest Dynamics ◽

Abiotic Factors ◽

Pine Forests ◽

Natural Disturbances ◽

Development History ◽

History Of ◽

Scots Pine Forests ◽

The Impact

The aim of this paper is to demonstrate the use of dendroecological methods to analyse the various processes involved in forest dynamics. Using dendroecological case studies of the Scots pine forests of Valais (Switzerland) as an example we discuss the most relevant processes of forest dynamics and their consequences on stand structures and mortality rates. We focus on the development history of these Scots pine forests under human impact and on the impact of biotic and abiotic factors on tree growth. Most of today's extended Scots pine forests (< 1500 m a.s.l.)must be interpreted as part of an ongoing natural succession under heavy human influence. In time, without management or natural disturbances, most of these pine forests will develop into broadleaved forests (lower altitudes) or spruce-firforests(higher altitudes).

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Effects of nitrogen, phosphorus, EDTA and sodium chloride on biomass and lipid accumulation of Chaetomorpha aerea

Current Botany ◽

10.25081/cb.2020.v11.6223 ◽

2020 ◽

pp. 152-158

Author(s):

Gour Gopal Satpati ◽

Ruma Pal

Keyword(s):

Fatty Acids ◽

Sodium Chloride ◽

Total Lipid ◽

Lipid Accumulation ◽

Saturated Fatty Acids ◽

Stress Conditions ◽

Biodiesel Production ◽

Cultural Conditions ◽

Chaetomorpha Aerea ◽

Nitrogen Phosphorus

The increase of total lipid and fatty acids production was studied under different nutrient stress conditions using the macroalga, Chaetomorpha aerea. The effects of nitrogen, phosphorus, ethylene diamine tetra-acetate and sodium chloride on the growth and lipid accumulation were systematically investigated in laboratory conditions. The biomass was harvested at different stages of cultivation and assessed. The maximum changes of growth and lipid accumulation were observed in the exponential phase at different cultural conditions. The two-fold increase of total lipid was found in the order of 28.27±0.04 % (at 0.1 g/L nitrogen) > 27.30±0.37 % (at 0.5 g/L of phosphorus) > 25.86±0.77 % (at 0.05 g/L of EDTA)> 24.37±0.04 % (at 0.05 g/L NaCl) on 8th day of cultivation. The fatty acids were identified and quantified by gas chromatography mass spectrometry (GC-MS). The alga produces significantly high amount of monounsaturated fatty acid (MUFA) and saturated fatty acids (SFA) than the polyunsaturated fatty acids (PUFA) in different cultural conditions. The elevated levels of C16:1, C18:1 and C20:1 was identified under nitrate, phosphate and salt stress conditions, which are more suitable for biodiesel production.

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Lipid accumulation of Chlorella sp. TLD6B from the Taklimakan Desert under salt stress

PeerJ ◽

10.7717/peerj.11525 ◽

2021 ◽

Vol 9 ◽

pp. e11525

Author(s):

Hong Li ◽

Jun Tan ◽

Yun Mu ◽

Jianfeng Gao

Keyword(s):

Salt Stress ◽

Fatty Acid ◽

Lipid Accumulation ◽

Large Scale ◽

Fatty Acid Biosynthesis ◽

High Salinity ◽

Raw Material ◽

Biodiesel Production ◽

Taklimakan Desert ◽

Acid Biosynthesis

Chlorella has become an important raw material for biodiesel production in recent years, and Chlorella sp. TLD6B, a species with high lipid concentrations and high salt and drought tolerance, has been cultivated on a large scale. To explore the lipid accumulation of Chlorella sp. TLD6B and its relationship to external NaCl concentrations, we performed physiological measurements and genome-wide gene expression profiling under different levels of salt stress. Chlorella sp. TLD6B was able to tolerate high levels of salt stress (0.8 M NaCl addition). Lipid concentrations initially increased and then decreased as salt stress increased and were highest under the addition of 0.2 M NaCl. Comparative transcriptomic analysis revealed that salt stress enhanced the expression of genes related to sugar metabolism and fatty acid biosynthesis (the ACCases BC and BCCP, KAS II, and GPDHs involved in TAG synthesis), thereby promoting lipid accumulation under the addition of 0.2 M NaCl. However, high salinity inhibited cell growth. Expression of three SADs, whose encoded products function in unsaturated fatty acid biosynthesis, was up-regulated under high salinity (0.8 M NaCl addition). This research clarifies the relationship between salt tolerance and lipid accumulation and promotes the utilization of Chlorella sp. TLD6B.

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Virulence and Pathogenicity of Chytrid Fungi Causing Amphibian Extinctions

Annual Review of Microbiology ◽

10.1146/annurev-micro-052621-124212 ◽

2021 ◽

Vol 75 (1) ◽

Author(s):

Matthew C. Fisher ◽

Frank Pasmans ◽

An Martel

Keyword(s):

Online Publication ◽

Abiotic Factors ◽

Amphibian Declines ◽

Host Responses ◽

Annual Review ◽

Publication Date ◽

Emerging Infections ◽

Biological Methods ◽

The Impact ◽

Highly Virulent

Ancient enzootic associations between wildlife and their infections allow evolution to innovate mechanisms of pathogenicity that are counterbalanced by host responses. However, erosion of barriers to pathogen dispersal by globalization leads to the infection of hosts that have not evolved effective resistance and the emergence of highly virulent infections. Global amphibian declines driven by the rise of chytrid fungi and chytridiomycosis are emblematic of emerging infections. Here, we review how modern biological methods have been used to understand the adaptations and counteradaptations that these fungi and their amphibian hosts have evolved. We explore the interplay of biotic and abiotic factors that modify the virulence of these infections and dissect the complexity of this disease system. We highlight progress that has led to insights into how we might in the future lessen the impact of these emerging infections. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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Soil Microbial Biomass and Community Composition Relates to Poplar Genotypes and Environmental Conditions

Forests ◽

10.3390/f11030262 ◽

2020 ◽

Vol 11 (3) ◽

pp. 262 ◽

Cited By ~ 3

Author(s):

Leszek Karliński ◽

Sabine Ravnskov ◽

Maria Rudawska

Keyword(s):

Microbial Biomass ◽

Microbial Communities ◽

Community Composition ◽

Soil Depth ◽

Abiotic Factors ◽

Soil Conditions ◽

Main Role ◽

Site Factors ◽

Host Genotype ◽

The Impact

Poplars, known for their diversity, are trees that can develop symbiotic relationships with several groups of microorganisms. The genetic diversity of poplars and different abiotic factors influence the properties of the soil and may shape microbial communities. Our study aimed to analyse the impact of poplar genotype on the biomass and community composition of the microbiome of four poplar genotypes grown under different soil conditions and soil depths. Of the three study sites, established in the mid-1990s, one was near a copper smelter, whereas the two others were situated in unpolluted regions, but were differentiated according to the physicochemical traits of the soil. The whole-cell fatty acid analysis was used to determine the biomass and proportions of gram-positive, gram-negative and actinobacteria, arbuscular fungi (AMF), other soil fungi, and protozoa in the whole microbial community in the soil. The results showed that the biomass of microorganisms and their contributions to the community of organisms in the soil close to poplar roots were determined by both factors: the tree-host genotype and the soil environment. However, each group of microorganisms was influenced by these factors to a different degree. In general, the site effect played the main role in shaping the microbial biomass (excluding actinobacteria), whereas tree genotype determined the proportions of the fungal and bacterial groups in the microbial communities and the proportion of AMF in the fungal community. Bacterial biomass was influenced more by site factors, whereas fungal biomass more by tree genotype. With increasing soil depth, a decrease in the biomass of all microorganisms was observed; however, the proportions of the different microorganisms within the soil profile were the result of interactions between the host genotype and soil conditions. Despite the predominant impact of soil conditions, our results showed the important role of poplar genotype in shaping microorganism communities in the soil.

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