Changes In Abiotic Factors Research Articles

Cooperation Between Photosynthetic and Antioxidant Systems: An Important Factor in the Adaptation of Ulva prolifera to Abiotic Factors on the Sea Surface.

Large-scale green tides have occurred continuously in the Yellow Sea of China from 2007 to 2018, and the causative species of the Yellow Sea green tide (YSGT) is Ulva prolifera. The thalli form floated thallus mats, and the thalli from different layers of the thallus mat suffer significantly different environmental conditions. In the present study, the environmental conditions of the surface layer (SL), middle layer (ML), and lower layer (LL) of the thallus mat from mid-June (Stage I) to mid-July (Stage II) were simulated. Photosynthetic traits and antioxidant systems were measured. The results showed that (1) photoprotective [non-photochemical quenching (NPQ) and cyclic electron transport (CEF)] and antioxidant systems both play important roles in protecting against abiotic factors in U. prolifera. (2) Cooperation between NPQ and CEF was observed in the ML group; CEF and the antioxidant system in the SL group work synergistically to protect the thalli. Furthermore, an inferred spatiotemporal attribute regarding the YSGT is presented: the significant changes in abiotic factors on the sea surface can easily affect the thalli of SL and ML from mid-June to mid-July, and those of LL can be affected in mid-July. This cooperation combined with the spatiotemporal attributes offers an explanation for the annual occurrence of the YSGT.HIGHLIGHTS –Adaptive mechanisms of Ulva prolifera against abiotic factors. –Cooperation between photosynthetic and antioxidant systems. –Spatiotemporal attributes regarding the Yellow Sea green tide are presented.

Altitude effects on spatial components of vascular plant diversity in a subarctic mountain tundra.

Environmental gradients are caused by gradual changes in abiotic factors, which affect species abundances and distributions, and are important for the spatial distribution of biodiversity. One prominent environmental gradient is the altitude gradient. Understanding ecological processes associated with altitude gradients may help us to understand the possible effects climate change could have on species communities. We quantified vegetation cover, species richness, species evenness, beta diversity, and spatial patterns of community structure of vascular plants along altitude gradients in a subarctic mountain tundra in northern Sweden. Vascular plant cover and plant species richness showed unimodal relationships with altitude. However, species evenness did not change with altitude, suggesting that no individual species became dominant when species richness declined. Beta diversity also showed a unimodal relationship with altitude, but only for an intermediate spatial scale of 1 km. A lack of relationships with altitude for either patch or landscape scales suggests that any altitude effects on plant spatial heterogeneity occurred on scales larger than individual patches but were not effective across the whole landscape. We observed both nested and modular patterns of community structures, but only the modular patterns corresponded with altitude. Our observations point to biotic regulations of plant communities at high altitudes, but we found both scale dependencies and inconsistent magnitude of the effects of altitude on different diversity components. We urge for further studies evaluating how different factors influence plant communities in high altitude and high latitude environments, as well as studies identifying scale and context dependencies in any such influences.

Dinamika Struktur Komunitas Mikroalga Kodominan Waduk Sutami Malang Akibat Penambahan Variasi Konsentrasi Deterjen secara Ex-Situ

The study aims to determine the response of microalgae community structure codominant and abiotic factors change Sutami Malang waters due to the addition of the detergent concentration variation in ex-situ. The experiment was conducted in September 2007 to March 2008. The addition of the detergent concentration consists of four levels, namely D0 (0 ppm), D1 (0.1 ppm), D2 (2 ppm) and D3 (4 ppm) of detergent to the water reservoir. Variable dynamics of microalgae abundance and abiotic factors waters observed simultaneously and periodically every five days for 40 days. The results showed that increasing the concentration of detergent changing dynamics of microalgae community structure codominant. Detergents suppress the growth Ceratium at a concentration ≥ 0.1 ppm. Instead detergent Synedra population increases until day 30 and stimulate the growth of Microcystis. During the 40 days of observation, abiotic factors change due to the addition of detergent concentration, especially the increase in conductivity, Total Organic Matter, phosphate, nitrate and surfactant. In contrast to lower CO2-free detergents and Dissolved Oxygen. Changes in abiotic factors significantly affect the growth of microalgae codominant.

Living on the edge: Gamete release and subsequent fertilisation in Fucus vesiculosus (Phaeophyceae) are weakened by climate change–forced hyposaline conditions

ABSTRACTPopulations at range margins of marine organisms are at the front line of climate-induced changes in abiotic factors and are thus particularly susceptible. Especially, macroalgae that are externally reproducing rely on optimal environmental conditions for gamete release and subsequent fertilisation. However, the effect of climate change–forced decrease in salinity on these critical life stages has been largely overlooked. We tested the impact of forecasted hyposaline conditions on a marginal population of the rockweed Fucus vesiculosus growing at 5.8 PSU on the Finnish coast of the Baltic Sea. We incubated individuals with receptacles for at least seven days at 2.5, 4.1, 5.8, and 7.2 PSU and determined their gamete release and subsequent fertilisation success. We further tested sperm performance at 3.5, 5.0, and 6.1 PSU. Salinity of 2.5 PSU, which is predicted to occur in the region by the end of this century, reduced egg release. In contrast, sperm and antheridia release were not consistently affected by the different salinities, but the size of sperm swells at 3.5 PSU. Because fertilisation success was drastically reduced at 2.5 and 4.1 PSU, we suggest that sperm performance was compromised such that sperm dysfunction hampered fertilisation success. Our results demonstrate that the forecasted hyposalinity negatively affects egg release and sexual reproduction in F. vesiculosus at its northern distribution limit. This macroalga can probably only withstand the future decrease in salinity when populations proliferate via asexual reproduction.

Changes in bacterial community composition across natural grassland and pine forests in the Bunya Mountains in subtropical Australia

Tree and grass species coexist in many ecosystems worldwide and support multiple ecosystem functions and services. However, the distribution of bacterial communities and factors driving coexistence in tree–grass associations and their ecosystem functions remain poorly understood. In this study, the distribution of soil bacteria and their link to changes in abiotic factors were investigated in adjacent montane grassland (C4 plants) and pine forest (bunya pine and hoop pine; C3 plants) sites in the Bunya Mountains, subtropical Australia. Different vegetation (grassy balds and forest) had a substantial effect on terrestrial ecosystem properties, with higher levels of soil nutrients (e.g. total nitrogen (N), total phosphorus (P)) and electrical conductivity (EC), and lower δ13C values and pH under forests compared with grassland. Bacterial α-diversity (total species per operational taxonomic unit richness) did not differ between grassland and pine forest sites, whereas strong shifts in the bacterial community composition and structure were evident. Patterns in bacterial community structure were strongly associated with changes in soil pH, EC, total P and δ13C. Different bacterial groups associated with pine forest (Gammaproteobacteria and Alphaproteobacteria) and grassland (Acidobacteria and Verrucomicrobia) were identified as key groups contributing to the segregation of these two ecosystems in the Bunya Mountains. These findings suggest that heterogeneity in soil edaphic properties (e.g. key nutrients) likely contributed to variation in bacterial β-diversity of grassland and pine forest, which has potential implications for species coexistence and ecosystem function in montane eastern Australia.

THE EFFECT OF ABIOTIC FACTORS ON WATER EXCHANGE IN CONIFEROUS AND DECIDUOUS PLANTS

The effects of abiotic factors (rate of PAR, air temperature and relative humidity, vapor pressure deficit) on the daily dynamics of the water potential in foliated (needled) shoots of Scots pine ( Pinus sylvestris L.) and silver birch ( Betula pendula Roth) trees during the growing season were studied in a fresh bilberry pine forest in the European part of the middle taiga (southern Karelia). Based on the analysis of model data, it was established that the contributions of the leading environmental factors to the formation of the water potential in coniferous and deciduous plants are comparable, and no interspecific differences were found. The similarity of the environmental factors dominance is shown for the two species, namely PAR rate effect dominance in July, relative air humidity in August, air temperature in September. In June, however, significant differences between the species were revealed in the governing influence of environmental factors on the water exchange in Scots pine (relative air humidity) and silver birch (PAR rate). These differences are supposed to be due to the biological traits of the formation of shoots and leaves (needles) in the coniferous and deciduous plants during the period of intensive growth. At the same time, we observed a somewhat inert response of the water potential in the foliated shoots of woody plants to abrupt changes in abiotic factors during the day, which is due to the mechanism of endogenous regulation of the water exchange. The similarity of the leading abiotic factors and their contributions to the formation of the water potential for coniferous and deciduous woody plants through the growing season suggests that taxonomically different species growing in the same climatic region have similar adaptation mechanisms.

Limited response of a spring bloom community inoculated with filamentous cyanobacteria to elevated temperature and pCO2

Abstract Temperature and CO2 levels are projected to increase in the future, with consequences for carbon and nutrient cycling in brackish environments, such as the Baltic Sea. Moreover, filamentous cyanobacteria are predicted to be favored over other phytoplankton groups under these conditions. Under a 12-day outdoor experiment, we examined the effect on a natural phytoplankton spring bloom community of elevated temperature (from 1°C to 4°C) and elevated pCO2 (from 390 to 970 μatm). No effects of elevated pCO2 or temperature were observed on phytoplankton biovolumes, but a significantly higher photosystem II activity was observed at elevated temperature after 9 days. In addition, three species of diazotrophic filamentous cyanobacteria were inoculated to test their competitive capacity under spring bloom conditions. The toxic cyanobacterium Nodularia spumigena exhibited an average specific growth rate of 0.10 d−1 by the end of the experiment, indicating potential prevalence even during wintertime in the Baltic Sea. Generally, none of the inoculated cyanobacteria species were able to outcompete the natural phytoplankton species at temperatures ≤4°C. No direct effects were found on heterotrophic bacteria. This study demonstrates the highly efficient resistance towards short-term (12 days) changes in abiotic factors by the natural Baltic Sea spring bloom community.

The Spatial Distribution of Perch (Perca fluviatilis) Ectoparasites and the Effect of Chemical Water Quality Parameters on Ectoparasite Spatial Niche Size

Abstract Seasonal changes of abiotic factors and their influence on parasite occurrence have repeatedly been studied. Most of the studies have been conducted to evaluate the effect of water physicochemical parameters on changes in the intensity of infection, prevalence and component community of a number of parasite species. However, insufficient attention has been paid to the link between water quality parameters and spatial niche size of ectoparasites. The distribution of ectoparasite species on perch (Perca fluviatilis L.) was studied to establish whether seasonal changes of water quality parameters are associated with ectoparasite spatial niche size. The concentration of phosphates (PO4 3−), nitrates (NO− 3), sulphates (SO4 2−) and dissolved oxygen (DO) in the water of Lake Sila (Latvia) was measured every month throughout the year and recorded all ectoparasites on perch. Zero-inflated mixed models were used to evaluate which of the water parameters influence the spatial niche size of ectoparasites. Our findings showed that spatial niche size of some ectoparasite species is affected by a set of water quality parameters and that this effect is negative. The spatial niche size of Anodonta cygnea was negatively associated with phosphate, nitrate, sulphate and dissolved oxygen concentration. The spatial niche size of Ancyrocephalus percae was negatively associated with sulphate, and the spatial niche size of Ergasilus sieboldi was negatively associated with nitrate concentration.

Seasonal succession of small planktonic eukaryotes inhabiting surface waters of a coastal upwelling system.

Small eukaryotes (0.2-20 μm cell-size) represent a significant fraction of the microbial plankton community in shelf waters of NW-Spain. The community composition of small eukaryotes living at the surface and at the base of the photic zone was analysed by means of 18S rDNA high-throughput sequencing on a circa-monthly basis over a 23 months period. Ostreococcus was the most abundant taxon in surface waters, showing marked peaks in read abundance in spring and late summer, while Syndiniales dominated at the base of the photic zone. A well-defined seasonal pattern of community composition, linked to the succession of the dominant taxa, was found in surface waters. Seasonality was less apparent at the base of the euphotic zone. Temporal changes in abiotic factors significantly correlated with changes in community composition in surface (r = 0.71) and at the base of the photic zone (r = 0.38). Changes in community composition significantly correlated with changes in community function-related variables (including biomass, primary production and respiration) only in surface water (r = 0.36). Co-occurrence network analyses revealed 45 significant interspecies associations among the 50 most abundant taxa with highly connected OTUs belonging to cryptophyceans. The network topology, with small-world characteristics, suggests a stabilizing role of biotic interactions to environmental disturbance.

A STUDY ON THE RELATIONSHIP AMONG ZOOPLANKTONS AND DIFFERENT ABIOTIC FACTORS AT BARDA BANDHARAN WETLAND, KODINAR

Wetland ecosystems are among the most productive ecosystems in the biosphere. Wetland ecosystem supports the growth of Biodiversity. Hydrology of wetland water gives idea about physical and chemical properties of water and their relationship with ecosystem Biodiversity. In present study we investigate relation between Abiotic factors on Zooplankton Diversity. Phytoplankton is integral components of freshwater wetlands, which significantly contribute towards succession and dynamics of zooplankton and fish.
 In preset study we have investigated Zooplankton Diversity fluctuation with changing Abiotic factors during Pre, Middle and post winter during 2016-17 of Barda Bandharan (Temporary wetland) near Barda Village, Kodinar, Gujarat.

Unexplained interannual oscillations of cyanobacterial blooms in the Baltic Sea

Population oscillations in multi-species or even single species systems are well-known but have rarely been detected at the lower trophic levels in marine systems. Nitrogen fixing cyanobacteria are a major component of the Baltic Sea ecosystem and sometimes form huge surface accumulations covering most of the sea surface. By analysing a satellite-derived 39-year (1979–2017) data archive of surface cyanobacteria concentrations we have found evidence of strikingly regular interannual oscillations in cyanobacteria concentrations in the northern Baltic Sea. These oscillations have a period of ~3 years with a high-concentration year generally followed by one or two low-concentration years. Changes in abiotic factors known to influence the growth and survival of cyanobacteria could not provide an explanation for the oscillations. We therefore assume that these oscillations are intrinsic to the marine system, caused by an unknown, probably mainly biological mechanism that may be triggered by a combination of environmental factors. Interactions between different life cycle stages of cyanobacteria as well as between predator-prey or host-parasite are possible candidates for causing the oscillations.

Differential accumulation of proteins in oil palms affected by fatal yellowing disease.

There is still no consensus on the true origin of fatal yellowing, one of the most important diseases affecting oil palm (Elaeis guineensis Jacq.) plantations. This study involved two-dimensional liquid chromatography coupled with tandem mass spectrometry (2D-UPLC-MSE) analyses to identify changes in protein profiles of oil palms affected by FY disease. Oil palm roots were sampled from two growing areas. Differential accumulation of proteins was assessed by comparing plants with and without symptoms and between plants at different stages of FY development. Most of the proteins identified with differential accumulation were those related to stress response and energy metabolism. The latter proteins include the enzymes alcohol dehydrogenase and aldehyde dehydrogenase, related to alcohol fermentation, which were identified in plants with and without symptoms. The presence of these enzymes suggests an anaerobic condition before or during FY. Transketolase, isoflavone reductase, cinnamyl alcohol dehydrogenase, caffeic acid 3-O-methyltransferase, S-adenosylmethionine synthase, aldehyde dehydrogenase and ferritin, among others, were identified as potential marker proteins and could be used to guide selection of FY-tolerant oil palm genotypes or to understand the source of this anomaly. When comparing different stages of FY, we observed high accumulation of alcohol dehydrogenase and other abiotic stress related-proteins at all disease stages. On the other hand, biological stress-related proteins were more accumulated at later stages of the disease. These results suggest that changes in abiotic factors can trigger FY development, creating conditions for the establishment of opportunistic pathogens.

Compositional and functional consequences of environmental change in Belgian farmland ponds

Abstract A resampling of 38 small farmland ponds in Belgium after 10 years revealed a high temporal species turnover for both phytoplankton and zooplankton communities, associated with substantial changes in abiotic factors, especially a reduction in total phosphorus concentration. Across ponds, phytoplankton biomass decreased while evenness and richness increased between the samplings in 2003 and 2013. By contrast, the zooplankton assemblage was characterised by lower biomass, richness and evenness in 2013. Ponds experiencing larger environmental change showed stronger changes in phytoplankton richness and evenness. Resource use efficiency (RUE) of zooplankton increased with greater environmental change and zooplankton evenness, which points to a switch towards species with higher RUE or greater variety in food sources in higher trophic levels. As ponds are important habitats for freshwater biodiversity and ecosystems services, the strong but predictable species turnover and the opposing effects of environmental change on different trophic levels need to be embedded in conservation and management plans.

Fish prey of Weddell seals, Leptonychotes weddellii, at Hope Bay, Antarctic Peninsula, during the late summer

The study of the feeding habits of Weddell seals, Leptonychotes weddellii, in the area of west Antarctic Peninsula is essential to understand the role they play in the marine food webs, especially considering that this is one of the regions most affected by climate change. With the aim of detecting temporal changes in the fish predation pattern of seals, a total of 217 scats were collected at Hope Bay, during three consecutive summers (2003, 2004 and 2005). The family Nototheniidae comprised over 80% in numbers of fish preyed by seals. The Antarctic silverfish, Pleuragramma antarctica, was, by far, the most frequent and abundant prey species with a mean percentage frequency of occurrence of 48.7% and representing in average 52.1% in numbers of the fish consumed by seals. Other fish species of lesser importance were the nototheniids Trematomus newnesi, Lepidonotothen larseni, Gobionotothen gibberifrons and the channichthyid Chionodraco rastrospinosus. Temporal variation was observed not only in the relative proportions of the different fish prey taxa but also in the sizes of the dominant prey, P. antarctica. Given the high trophic vulnerability of this species to changes in abiotic factors and food web structure and dynamics, a possible influence of El Nino Southern Oscillation events of 2002–2003 and 2004–2005 should not be discarded. Moreover, special attention should be addressed to its population status, distribution and spatial/temporal availability as prey resource of upper trophic level consumers such as L. weddellii which largely depend on P. antarctica.

Activity of wild Japanese macaques in Yakushima revealed by camera trapping: Patterns with respect to season, daily period and rainfall.

Animals are subject to various scales of temporal environmental fluctuations, among which daily and seasonal variations are two of the most widespread and significant ones. Many biotic and abiotic factors change temporally, and climatic factors are particularly important because they directly affect the cost of thermoregulation. The purpose of the present study was to determine the activity patterns of wild Japanese macaques (Macaca fuscata) with a special emphasis on the effect of thermal conditions. We set 30 camera traps in the coniferous forest of Yakushima and monitored them for a total of 8658 camera-days between July 2014 and July 2015. Over the one-year period, temperature had a positive effect, and rainfall had a negative effect on the activity of macaques during the day. Capture rate was significantly higher during the time period of one hour after sunrise and during midday. During winter days, macaques concentrated their activity around noon, and activity shifted from the morning toward the afternoon. This could be interpreted as macaques shifting their activity to warmer time periods within a single day. Japanese macaques decreased their activity during the time before sunrise in seasons with lower temperatures. It was beneficial for macaques to be less active during cooler time periods in a cold season. Even small amounts of rainfall negatively affected the activity of Japanese macaques, with capture rates decreasing significantly even when rainfall was only 0.5–1 mm/min. In conclusion, thermal conditions significantly affected the activity of wild Japanese macaques at various time scales.

The effects of fungal root endophytes on plant growth are stable along gradients of abiotic habitat conditions.

Plant symbioses with fungal root endophytes span a continuum from mutualistic to parasitic outcomes, and are highly variable depending on the genotype of each symbiont. The abiotic context in which interactions occur also seems to influence the outcome of plant-endophyte symbioses, but we lack understanding of its relative importance. We aimed to assess if changes in abiotic variables determine the effects of fungal root endophytes on plant growth. We used in vitro co-cultivation assays to test the impact of a selection of endophytic strains from diverse lineages on the growth of Arabidopsis thaliana, Microthlaspi erraticum and Hordeum vulgare along gradients of nutrient availability, light intensity or substrate pH. Most fungi showed a negative but weak effect on plant growth, whereas only a few had persistent detrimental effects across plants and conditions. Changes in abiotic factors affected plant growth but had little influence on their response to fungal inoculation. Of the factors tested, variation in nutrient availability resulted in the most variable plant-endophyte interactions, although changes were feeble and strain-specific. Our findings suggest that the effects of root endophytes on plant growth are robust to changes in the abiotic environment when these encompass the tolerance range of either symbiont.

Water relations in the soil crust lichen Psora decipiens are optimized via anatomical variability

AbstractBiological soil crusts are communities composed of cryptogamic organisms such as lichens, mosses, cyanobacteria and green algae that form a skin on soils in areas where vascular plants are excluded or limited by water availability or temperature. The lichen Psora decipiens (Hedw.) Hoffm. is a characteristic key organism in these communities in many different biomes. The species has a generalistic ecology and high morphological variation, which contributes to the ability of the species to withstand environmental changes. We investigated whether different populations, based on site and associated morpho-anatomical differences, incorporate functional water relations and how/whether this was driven by changes in abiotic factors. Samples were collected from two climatically distinct sites, one ‘dry’ site in southern Spain and one ‘wet’ site in the Austrian Alps. Our results showed that samples from the dry site had a significantly thicker epinecral layer, higher specific thallus area, a faster water uptake and contained more water per dry mass, all of which contributed to a much slower drying rate. Both populations showed a highly adjusted water gain that incorporates functional water relations and diffusion properties as a result of local water availability. We show eco-physiological and morphological mechanisms that underlie the high variability in P. decipiens and suggest how these might provide ecological benefits for this generalist lichen species.

Warming-induced shift towards forbs and grasses and its relation to the carbon sequestration in an alpine meadow

Global warming is often associated with changes in abiotic factors and the community composition across alpine ecosystems. However, the way that an altered community dynamics affects the ecosystem carbon (C) balance remains unclear. A warming experiment was initiated in 2010 to assess the potential impacts of warming-induced changes in the community composition and how these changes affect the C balance in mountain meadows located in the permafrost region of the Qinghai–Tibet Plateau (China).Under warming conditions, we found an increased importance value (IV) of forbs and grasses of 4.9%, in contrast to the IV of sedges, which decreased by 4.4%. For forbs and grasses, the IV showed positive exponential relationships with gross ecosystem production and ecosystem respiration, while negative correlations were found for sedges. These results indicate that a slight change in the IVs of sedges, grasses and forbs favors C sequestration. Moreover, the warming treatment significantly increased the mean height of sedges, grasses and forbs, and the net ecosystem exchange increase was positively correlated with the increase in the mean height of grasses and forbs. In summary, the warming-induced shift toward forb and grass species and the increase in plant height strengthen the C uptake capacity of alpine meadow ecosystems.

The colonization and succession patterns of the periphytic ciliate community in a temperate floodplain lake

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Light absorption and impacts of low salinities on photosynthetic behaviour in the epiphytic alga Neosiphonia savatieri (Rhodomelaceae, Rhodophyta)

Filamentous epiphyte outbreaks, a serious problem in the commercial cultivation of Kappaphycus/Eucheuma, are often triggered by large changes in abiotic factors. However, the physiological characteristics of epiphytes are poorly understood. In this study, the main pigment contents of Neosiphonia savatieri and its healthy host strains, including green thalli of Kappaphycus striatum (G-KS), brown and green thalli of Kappaphycus alvarezii (B-KA, G-KA), were quantified. The light absorption capacities of lipid- and water-soluble pigments of these seaweeds were also measured. Photosynthetic parameters, including pigment content and fast chlorophyll a fluorescence kinetics, were further studied in N. savatieri exposed to different salinities (16–34 psu) for 10 h in an outdoor experiment. The phycobiliprotein (PBP), Chl-a, and carotenoid contents of N. savatieri were comparatively higher than the hosts, with the values of 2.50, 0.29, and 0.12 mg g−1 (fw), respectively. The mean extinction coefficients of lipid- and water-soluble pigments in N. savatieri were both higher than G-KS, B-KA, and G-KA in the 400–700 nm bands. Salinity of 28 psu increased the pigment contents of the epiphyte, and 16–22 psu did not have a negative impact. Polyphasic fluorescence transients revealed that salinities at 22–28 psu were beneficial to photosynthetic electron transport, mainly attributed to the enhancement of energy absorption per active PSII reaction centre. Given these observations, N. savatieri has a higher light-harvesting capacity and better tolerance to low salinities. These two physiological properties made N. savatieri well suited to the low light and hypo-saline conditions that are frequently triggered by fluctuations in abiotic factors.