scholarly journals The effects of resource subsidy duration on detritus-based stream ecosystem: a stream mesocosm experiment

2019 ◽  
Author(s):  
Takuya Sato ◽  
Rui Ueda ◽  
Gaku Takimoto
Keyword(s):  
Ingestion Rate ◽  
Mesocosm Experiment ◽  
Ecosystem Functions ◽  
Resource Subsidies ◽  
Ecological Processes ◽  
Breakdown Rate ◽  
Positive Effects ◽  
Growing Seasons ◽  
Benthic Prey

SummaryMost of the resource subsidies are temporally variable, and studies have revealed that ecological processes can be mediated by the temporal attributes of subsidies, such as timing and frequency. Less studies have, however, examined the effects of the subsidy duration, an another major temporal attribute, on consumer populations, communities and ecosystem functions. Using an outdoor mesocosm experiment, we demonstrated that, even with the same total amounts, the prolonged subsidy let large-stage fish effectively monopolize the subsidy over small-stage fish, while the pulsed subsidy allowed small-stage fish to increase the ingestion rate of the subsidy. This effect resulted in causing weaker indirect positive effects on in-situ benthic prey and a leaf breakdown rate with the prolonged subsidy than with the pulsed-subsidy although it depended on dominant benthic prey species having different edibility. Increasing evidences have shown that global warming would not only advance, but also prolong the growing seasons, which may, in turn, make subsidies more prolonged. The ecological significance of the subsidy duration might be common in nature, and should be incorporated to better understand ecological processes in spatially and temporally coupled ecosystems.

scholarly journals The Influence of Biochar, Slow-Release Molasses, and an Organic N:P:K Fertilizer on Transplant Survival of Pyrus communis ‘Williams’ Bon Chrétien’

2016 ◽  
Vol 42 (2) ◽  
Author(s):  
Emma Schaffert ◽  
Glynn Percival
Keyword(s):  
Slow Release ◽  
Soil Amendments ◽  
Pyrus Communis ◽  
Low Fertility ◽  
Economic Losses ◽  
Soil Conditions ◽  
Urban Landscapes ◽  
Transplant Survival ◽  
Positive Effects ◽  
Growing Seasons

High mortality rates result from transplanting bare-rooted plants into urban landscapes where unsuitable soil conditions, such as low fertility and poor structure, often exist. Coupled with little aftercare, these losses can cause high economic losses to the industry. Previous studies have shown lowered transplant stress and higher survival rates through the addition of soil amendments at the time of planting to improve soil conditions. The efficacy of three soil amendments applied singly and in combination—biochar, slow-release molasses, and an organic N:P:K fertilizer—were investigated for their potential to reduce transplant losses of Pyrus communis ‘Williams’ Bon Chrétien. Results of this investigation showed that use of these soil amendments in virtually all cases had significant positive effects on tree growth and vitality across two growing seasons. For example, all amendments reduced mortality of Pyrus communis ‘Williams’ Bon Chrétien’ by 20% compared to none in treated controls, while increases in fruit yield and crown canopy coverage per tree ranged from 19.3% to 46.7% and 14.4% to 31.1% over non-amended soils when averaged over two growing seasons. Amendments of biochar with an organic N:P:K fertilizer and an organic N:P:K fertilizer alone showed, on average, the highest improvements in vitality and growth. Results indicate use of biochar, slow-release molasses, and organic N:P:K fertilizer amendments offer potential for increasing bare-root transplant survival and establishment of Pyrus communis ‘Williams’ Bon Chrétien.

scholarly journals Different processes shape prokaryotic and picoeukaryotic assemblages in the sunlit ocean microbiome

2018 ◽  
Author(s):  
Ramiro Logares ◽  
Ina M. Deutschmann ◽  
Caterina. R. Giner ◽  
Anders K. Krabberød ◽  
Thomas S. B. Schmidt ◽  
...  
Keyword(s):  
Ecosystem Function ◽  
Sequence Data ◽  
Scale Effects ◽  
Dispersal Limitation ◽  
Global Scale ◽  
Global Ocean ◽  
Ecosystem Functions ◽  
Ecological Processes ◽  
Surface Ocean

ABSTRACTThe smallest members of the sunlit-ocean microbiome (prokaryotes and picoeukaryotes) participate in a plethora of ecosystem functions with planetary-scale effects. Understanding the processes determining the spatial turnover of this assemblage can help us better comprehend the links between microbiome species composition and ecosystem function. Ecological theory predicts thatselection,dispersalanddriftare main drivers of species distributions, yet, the relative quantitative importance of these ecological processes in structuring the surface-ocean microbiome is barely known. Here we quantified the role of selection, dispersal and drift in structuring surface-ocean prokaryotic and picoeukaryotic assemblages by using community DNA-sequence data collected during the global Malaspina expedition. We found that dispersal limitation was the dominant process structuring picoeukaryotic communities, while a balanced combination of dispersal limitation, selection and drift shaped prokaryotic counterparts. Subsequently, we determined the agents exerting abiotic selection as well as the spatial patterns emerging from the action of different ecological processes. We found that selection exerted via temperature had a strong influence on the structure of prokaryotic communities, particularly on species co-occurrences, a pattern not observed among communities of picoeukaryotes. Other measured abiotic variables had limited selective effects on microbiome structure. Picoeukaryotes presented a higher differentiation between neighbouring communities and a higher distance-decay when compared to prokaryotes, agreeing with their higher dispersal limitation. Finally, drift seemed to have a limited role in structuring the sunlit-ocean microbiome. The different predominance of ecological processes acting on particular subsets of the ocean microbiome suggests uneven responses to environmental change.SIGNIFICANCE STATEMENTThe global ocean contains one of the largest microbiomes on Earth and changes on its structure can impact the functioning of the biosphere. Yet, we are far from understanding the mechanisms that structure the global ocean microbiome, that is, the relative importance of environmentalselection,dispersaland random events (drift). We evaluated the role of these processes at the global scale, based on data derived from a circumglobal expedition and found that these ecological processes act differently on prokaryotes and picoeukaryotes, two of the main components of the ocean microbiome. Our work represents a significant contribution to understand the assembly of marine microbial communities, providing also insights on the links between ecological mechanisms, microbiome structure and ecosystem function.

scholarly journals Divergent responses of biomass accumulation and its allocation to the altered precipitation regimes among different degraded grasslands in China

2021 ◽  
Author(s):  
Tianxue Yang ◽  
Junda Chen ◽  
Xiaoyue Zhong ◽  
Xuechen Yang ◽  
Gui Wang ◽  
...  
Keyword(s):  
Climate Models ◽  
Plant Biomass ◽  
Inorganic Nitrogen ◽  
Precipitation Amount ◽  
Soil Layer ◽  
Ecosystem Functions ◽  
Precipitation Frequency ◽  
Positive Effects ◽  
Altered Precipitation ◽  
Precipitation Regimes

Abstract Purpose Climate models predict shifts in precipitation patterns characterized by increased precipitation amount and decreased frequency for semi-arid grasslands in northeast China. However, under these novel climatic conditions, potential differences in plant biomass and its allocation among different degraded grasslands remain unclear.Methods We conducted a mesocosm experiment to test the effects of higher precipitation amount (increased by 50% from the long-term mean) and lower frequency (decreased by 50%) on plant biomass and allocation in the lightly degraded (LDG), moderately degraded (MDG), and severely degraded grasslands (SDG).Results Lower precipitation frequency promoted belowground biomass (BGB), while reducing aboveground biomass (AGB) allocation through enhancing soil water variability. Higher precipitation amount enhanced AGB in LDG and MDG, but not in SDG due to less soil inorganic nitrogen. Lower precipitation frequency weakened the positive effects of higher precipitation amount on biomass. Under altered precipitation, adjustment of AGB vs. BGB allocation was the primary biomass allocation strategy in LDG and SDG. However, to maintain water acquirement, plants in MDG preferred to adjust root vertical distribution, and allocated more roots to the deep soil layer where had a relatively stable water source. This strategy was driven by the changes in plant community composition of the dominant species in MDG.Conclusions The findings of this research emphasized the importance of considering the degradation level of grasslands when predicting the responses of the ecosystem functions to the projected changes in precipitation regime. These findings are critical for making feasible decisions for the sustainable management of degraded grasslands.

scholarly journals Positive effects of concomitant heavy metals and their reduzates on hexavalent chromium removal in microbial fuel cells

RSC Advances ◽  
2020 ◽  
Vol 10 (26) ◽  
pp. 15107-15115 ◽  
Author(s):  
Xiayuan Wu ◽  
Chunrui Li ◽  
Zuopeng Lv ◽  
Xiaowei Zhou ◽  
Zixuan Chen ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Fuel Cells ◽  
Hexavalent Chromium ◽  
Microbial Fuel Cells ◽  
Chromium Removal ◽  
Positive Effects ◽  
Bioelectricity Generation ◽  
Co Reduction

The cooperative cathode modification by BioAu from Au(iii) and in situ Cu(ii) co-reduction enhanced Cr(vi) removal and bioelectricity generation in MFCs.

Diurnal gross photosynthetic patterns and potential seasonal CO2 assimilation in Cladonia stellaris and Cladonia rangiferina

1983 ◽  
Vol 61 (3) ◽  
pp. 642-655 ◽  
Author(s):  
Thomas J. Moser ◽  
Thomas H. Nash III ◽  
Steven O. Link
Keyword(s):  
Photosynthetic Activity ◽  
Growing Season ◽  
Early Morning ◽  
Co2 Assimilation ◽  
Atmospheric Moisture ◽  
Growing Seasons ◽  
Late Evening ◽  
Summer Rain ◽  
Cladonia Rangiferina

The daily, in situ gross photosynthetic patterns of Cladonia stellaris (Opiz.) Pouz. & Vězda. and Cladonia rangiferina (L.) Wigg. were monitored during portions of the 1977, 1978, and 1979 growing seasons at Anaktuvuk Pass, Alaska. Photosynthetic activity in both species closely paralleled atmospheric moisture status, where peak photosynthetic rates were attained during or following sporadic summer rain. In addition, thallus absorption of moisture during extended periods of high atmospheric water vapor content gave rise to short periods of minimal photosynthetic activity. During late evening and early morning hours moistened thalli exhibited minimal or no photosynthetic activity, coinciding with consistent attenuation in solar radiation during these periods. Photosynthetic activity was not homogeneous throughout the thallus. The greatest activity occurred in the apical regions and decreased progressively into the basal regions. The apical 10-mm regions of C. stellaris and C. rangiferina thalli accounted for approximately 50% of their photosynthetic capabilities. The potential gross CO2 assimilation of the apical 10-mm regions over 72 days of the 1978 growing season was estimated at approximately 35 g CO2∙m−2 and 16 g CO2∙m−2 for C. stellaris and C. rangiferina, respectively.

scholarly journals Effects of diesel oil spill on macrobenthic assemblages at the intertidal zone: A mesocosm experiment in situ

2019 ◽  
Vol 152 ◽  
pp. 104823 ◽  
Author(s):  
Zhengquan Zhou ◽  
Xiaojing Li ◽  
Linlin Chen ◽  
Baoquan Li ◽  
Chuanyuan Wang ◽  
...  
Keyword(s):  
Oil Spill ◽  
Intertidal Zone ◽  
Diesel Oil ◽  
Mesocosm Experiment ◽  
Macrobenthic Assemblages

scholarly journals Exploring the Potential of Satellite Solar-Induced Fluorescence to Constrain Global Transpiration Estimates

2019 ◽  
Vol 11 (4) ◽  
pp. 413 ◽  
Author(s):  
Brianna Pagán ◽  
Wouter Maes ◽  
Pierre Gentine ◽  
Brecht Martens ◽  
Diego Miralles
Keyword(s):  
Eddy Covariance ◽  
Land Surface ◽  
Radiant Energy ◽  
Energy System ◽  
Plant Responses ◽  
Natural Ecosystem ◽  
Growing Seasons ◽  
Phenological Changes ◽  
Opening And Closing

The opening and closing of plant stomata regulates the global water, carbon and energy cycles. Biophysical feedbacks on climate are highly dependent on transpiration, which is mediated by vegetation phenology and plant responses to stress conditions. Here, we explore the potential of satellite observations of solar-induced chlorophyll fluorescence (SIF)—normalized by photosynthetically-active radiation (PAR)—to diagnose the ratio of transpiration to potential evaporation (‘transpiration efficiency’, τ). This potential is validated at 25 eddy-covariance sites from seven biomes worldwide. The skill of the state-of-the-art land surface models (LSMs) from the eartH2Observe project to estimate τ is also contrasted against eddy-covariance data. Despite its relatively coarse (0.5°) resolution, SIF/PAR estimates, based on data from the Global Ozone Monitoring Experiment 2 (GOME-2) and the Clouds and Earth’s Radiant Energy System (CERES), correlate to the in situ τ significantly (average inter-site correlation of 0.59), with higher correlations during growing seasons (0.64) compared to decaying periods (0.53). In addition, the skill to diagnose the variability of in situ τ demonstrated by all LSMs is on average lower, indicating the potential of SIF data to constrain the formulations of transpiration in global models via, e.g., data assimilation. Overall, SIF/PAR estimates successfully capture the effect of phenological changes and environmental stress on natural ecosystem transpiration, adequately reflecting the timing of this variability without complex parameterizations.

scholarly journals In situ pelagic dataset from continuous monitoring: A mesocosm experiment in Lake Geneva (MESOLAC)

Data in Brief ◽  
2020 ◽  
Vol 32 ◽  
pp. 106255
Author(s):  
Viet Tran-Khac ◽  
Philippe Quetin ◽  
Isabelle Domaizon ◽  
Stéphan Jacquet ◽  
Laurent Espinat ◽  
...  
Keyword(s):  
Continuous Monitoring ◽  
Mesocosm Experiment ◽  
Lake Geneva

scholarly journals Impaired benthic macrofauna function 4 years after sediment capping with activated carbon in the Grenland fjords, Norway

2020 ◽  
Author(s):  
Caroline Raymond ◽  
Göran S Samuelsson ◽  
Stefan Agrenius ◽  
Morten T Schaanning ◽  
Jonas S Gunnarsson
Keyword(s):  
Activated Carbon ◽  
Biological Effects ◽  
Benthic Communities ◽  
Ecosystem Functions ◽  
Sediment Surface ◽  
Sediment Remediation ◽  
Vital Functions ◽  
Southern Norway

AbstractThe sediments in the Grenland fjords in southern Norway are heavily contaminated by large emissions of dioxins and mercury from historic industrial activities. As a possible in situ remediation option, thin-layer sediment surface capping with powdered activated carbon (AC) mixed with clay was applied at two large test sites (10,000 and 40,000 m2) at 30-m and 95-m depths, respectively, in 2009. This paper describes the long-term biological effects of the AC treatment on marine benthic communities up to 4 years after treatment. Our results show that the capping with AC strongly reduced the benthic species diversity, abundance, and biomass by up to 90%. Vital functions in the benthic ecosystem such as particle reworking and bioirrigation of the sediment were also reduced, analyzed by using novel bioturbation and bioirrigation indices (BPc, BIPc, and IPc). Much of the initial effects observed after 1 and 14 months were still present after 49 months, indicating that the effects are long-lasting. These long-lasting negative ecological effects should be carefully considered before decisions are made on sediment remediation with powdered AC, especially in large areas, since important ecosystem functions can be impaired.

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