Quantifying the impact of drought on soil-plant interactions: a seasonal analysis of biotic and abiotic controls of carbon and nutrient dynamics in high-altitudinal grasslands

Biotic and abiotic processes that form, alter, transport, and remineralize particulate organic carbon, silicon, calcium carbonate, and other minor and trace chemical species in the water column are central to the ocean&#8217;s ecological and biogeochemical functioning and of fundamental importance to the ocean carbon cycle. Sinking particulate matter is the major vehicle for exporting carbon from the sea surface to the deep sea. During its transit towards the sea floor, most particulate organic carbon (POC) is returned to inorganic form and redistributed in the water column. This redistribution determines the surface concentration of dissolved CO2, and hence the rate at which the ocean can absorb CO2 from the atmosphere. The ability to predict quantitatively the depth profile of remineralization is therefore critical to deciphering the response of the global carbon cycle to natural and human-induced changes.Aiming to investigate the significant biogeochemical and ecological features and provide new insights on the sources and cycles of sinking particulate matter, a mooring line of five sediment traps was deployed from 2006 to 2015 (with some gap periods) at 5 successive water column depths (700, 1200, 2000, 3200 and 4300 m) in the SE Ionian Sea, northeastern Mediterranean (&#8216;NESTOR&#8217; site). We have examined the long-term records of downward fluxes for Corg, Ntot, &#948;13Corg and &#948;15Ntot, along with the associated ballast minerals (opal, lithogenics and CaCO3), lipid biomarkers, Chl-a and PP rates, phytoplankton composition, nutrient dynamics and atmospheric deposition. &#160;The satellite-derived seasonal and interannual variability of phytoplankton metrics (biomass and phenology) and atmospheric deposition (meteorology and air masses origin) was examined for the period of the sediment trap experiment. Regarding the atmospheric deposition, synergistic opportunities using Earth Observation satellite lidar and radiometer systems are proposed (e.g. Cloud&#8208;Aerosol Lidar with Orthogonal Polarization - CALIOP, Moderate Resolution Imaging Spectroradiometer - MODIS), aiming towards a four&#8208;dimensional exploitation of atmospheric aerosol loading (e.g. Dust Optical Depth) in the study area.Our main goals are to: i) develop a comprehensive knowledge of carbon fluxes and associated mineral ballast fluxes from the epipelagic to the mesopelagic and bathypelagic layers, ii) elucidate the mechanisms governing marine productivity and carbon export and sequestration to depth and iii) shed light on the impact of atmospheric forcing and deposition in respect to regional and large scale circulation patterns and climate variability and the prevailing oceanographic processes (internal variability).AcknowledgmentsWe acknowledge support of this work by the Action &#8216;National Network on Climate Change and its Impacts &#8211; CLIMPACT&#8217;, funded by the Public Investment Program of Greece (GSRT, Ministry of Development and Investments).

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The Role of Viruses in the Phytobiome

Annual Review of Virology ◽

10.1146/annurev-virology-092917-043421 ◽

2018 ◽

Vol 5 (1) ◽

pp. 93-111 ◽

Cited By ~ 14

Author(s):

James E. Schoelz ◽

Lucy R. Stewart

Keyword(s):

Soil Bacteria ◽

Plant Viruses ◽

Plant Health ◽

Plant Interactions ◽

Current Information ◽

Virus Interactions ◽

The Impact ◽

Review Current

Viruses are an important but sequence-diverse and often understudied component of the phytobiome. We succinctly review current information on how plant viruses directly affect plant health and physiology and consequently have the capacity to modulate plant interactions with their biotic and abiotic environments. Virus interactions with other biota in the phytobiome, including arthropods, fungi, and nematodes, may also impact plant health. For example, viruses interact with and modulate the interface between plants and insects. This has been extensively studied for insect-vectored plant viruses, some of which also infect their vectors. Other viruses have been shown to alter the impacts of plant-interacting phytopathogenic and nonpathogenic fungi and bacteria. Viruses that infect nematodes have also recently been discovered, but the impact of these and phage infecting soil bacteria on plant health remain largely unexplored.

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Seasonal and Spatial Nutrient Dynamics in Saronikos Gulf: The Impact of Sewage Effluents from Athens Sewage Treatment Plant

Eutrophication: Causes, Consequences and Control ◽

10.1007/978-94-007-7814-6_10 ◽

2013 ◽

pp. 111-130 ◽

Cited By ~ 1

Author(s):

A. Pavlidou ◽

H. Kontoyiannis ◽

N. Zarokanelos ◽

I. Hatzianestis ◽

G. Assimakopoulou ◽

...

Keyword(s):

Nutrient Dynamics ◽

Sewage Treatment ◽

Sewage Treatment Plant ◽

Treatment Plant ◽

Sewage Effluents ◽

The Impact

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Soil Nutrient Dynamics and Nitrogen Fixation Rate Changes over Plant Growth in Temperate Soil

Agronomy ◽

10.3390/agronomy9040179 ◽

2019 ◽

Vol 9 (4) ◽

pp. 179 ◽

Cited By ~ 4

Author(s):

Ágota Horel ◽

Györgyi Gelybó ◽

Imre Potyó ◽

Klára Pokovai ◽

Zsófia Bakacsi

Keyword(s):

Nitrogen Fixation ◽

Nutrient Dynamics ◽

Plant Biomass ◽

Soil Nutrient ◽

Initial Increase ◽

Pepper Plant ◽

Plant Interactions ◽

Fixation Rate ◽

Total N ◽

Fiber Sludge

Research on the use of soil enhancer materials such as biochar from soil chemical perspective still provide differing results; therefore, investigations focusing on soil-biochar-plant interactions are still necessary to constrain our understanding of complex biochar effects. The present study investigated the changes in biological nitrogen fixation rates (BNF) and overall nutrient dynamics (NO3−, NH4+, total N, K2O, and P2O5) during the growth of Capsicum annuum (pepper) in pot experiments amended with biochar made of paper fiber sludge and grain husk. Four treatments were studied with 0, 0.5%, 2.5%, and 5.0% (by weight) added biochar (BC) amount to temperate silt loam soil. Peppers were planted at 2–4 leave stages and grown for the duration of 12.5 weeks. Our results showed that total nitrogen had relatively small changes in all treatments over time compared to the dynamic changes observed in the case of inorganic nutrients. NO3−-N and NH4+-N abundances presented a continuous decrease during the course of the study after an initial increase. The pepper plant facilitated the BNF rates to triple in the control soils, while plants were in the growing phase (weeks 1–6), which further increased an additional 61% by harvesting (week 12). A high amount of biochar addition suppressed potential BNF rates of the investigated soil, indicating its potentially negative effects on soil indigenous microbial communities if added in excess. We also found a plateau in plant biomass production that after reaching an optimal (2.5%) biochar amendment in the soils, and excess biochar addition did not result in significant changes in the soils’ pH to achieve better nutrient (potassium, nitrogen, phosphorous) use or crop growth.

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Hemiparasite – host plant interactions and the impact of herbivory: a field experiment

Botany ◽

10.1139/b11-045 ◽

2011 ◽

Vol 89 (8) ◽

pp. 537-544 ◽

Cited By ~ 5

Author(s):

Mickayla D. Van Hoveln ◽

Bethany A. Evans ◽

Victoria A. Borowicz

Keyword(s):

Host Size ◽

Schizachyrium Scoparium ◽

Plant Interactions ◽

Compensatory Response ◽

Host Growth ◽

Subsequent Flowering ◽

Shoot Mass ◽

The Impact ◽

Early Late ◽

Pedicularis Canadensis

Schizachyrium scoparium Michx. (Nash) growing naturally with varying numbers of the perennial hemiparasite Pedicularis canadensis L. were randomly assigned to one of four clipping treatments (none, early, late, early and late) to determine how parasitism and herbivory affect the grass and whether herbivory of the host indirectly affects hemiparasite growth. Any clipping eliminated subsequent flowering by S. scoparium in year 1 and reduced the number of plants that flowered in year 2, when no clipping occurred. Only hosts clipped early exhibited depressed growth after one summer. The following year plants that had been clipped twice the previous year produced the least shoot mass, and plants that were never clipped produced the most. Hemiparasite load was negatively associated with host shoot mass, especially in year 1, but did not alter the host’s compensatory response to clipping. The effects of host size and host clipping on the nearest hemiparasite were determined in year 1. Pedicularis canadensis shoot mass declined with host size if the host was clipped late, but increased with host size when clipping occurred once early in the season. Although the impact of hemiparasites and clipping on host growth are independent, clipping can alter the value of the host for parasites.

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Host plant interactions between wheat germplasm source and wheat stem sawfly Cephus cinctus Norton (Hymenoptera: Cephidae) I. Commercial cultivars

Canadian Journal of Plant Science ◽

10.4141/cjps2012-088 ◽

2013 ◽

Vol 93 (4) ◽

pp. 607-617 ◽

Cited By ~ 9

Author(s):

B. L. Beres ◽

H. A. Cárcamo ◽

J. R. Byers ◽

F. R. Clarke ◽

C. J. Pozniak ◽

...

Keyword(s):

Host Plant ◽

Insect Pest ◽

Economic Losses ◽

Plant Interactions ◽

Wheat Stem Sawfly ◽

Cephus Cinctus ◽

Wheat Germplasm ◽

Commercial Cultivars ◽

Solid Stem ◽

The Impact

Beres, B. L., Cárcamo, H. A., Byers, J. R., Clarke, F. R., Pozniak, C. J., Basu, S. K. and DePauw, R. M. 2013. Host plant interactions between wheat germplasm source and wheat stem sawfly Cephus cinctus Norton (Hymenoptera: Cephidae) I. Commercial cultivars. Can. J. Plant Sci. 93: 607–617. The wheat stem sawfly (WSS) Cephus cinctus Norton (Hymenoptera: Cephidae) is an economically destructive insect pest of wheat in the northern Great Plains. A significant resurgence of the insect pest in the southern prairies of Canada caused substantial economic losses from 1999 through 2007. Solid-stem cultivar selection is critical to the management of WSS but adoption of the use of these cultivars was low, which compounded losses at harvest. A study was conducted from 2001 to 2003 in southern Alberta and Saskatchewan, Canada (1) to establish the range of susceptibility of hollow- and solid-stem varieties representing the major spring wheat classes and (2) to determine the impact of host plant on WSS population dynamics. The solid-stem varieties were generally superior at reducing damage and fitness response of WSS. However, in addition to the durum cultivars AC Navigator and AC Avonlea, the variety McKenzie, which was considered hollow, provided improved efficacy over other hollow-stem cultivars. Our study suggests solid-stem cultivars are highly effective but prone to inconsistent performance and should therefore be integrated into a holistic strategy for WSS that includes agronomics and biocontrol. A companion paper will report on the response of cultivars with novel sources of germplasm.

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purL gene expression affects biofilm formation and symbiotic persistence of Photorhabdus temperata in the nematode Heterorhabditis bacteriophora

Microbiology ◽

10.1099/mic.0.048959-0 ◽

2011 ◽

Vol 157 (9) ◽

pp. 2595-2603 ◽

Cited By ~ 11

Author(s):

Ruisheng An ◽

Parwinder S. Grewal

Keyword(s):

Gene Expression ◽

Metabolic Pathway ◽

Biofilm Formation ◽

Heterorhabditis Bacteriophora ◽

Bacterial Biofilm ◽

Infective Juvenile ◽

Plant Interactions ◽

Symbiotic Interaction ◽

The Impact ◽

Photorhabdus Temperata

Extensive studies of the well-known legume and rhizobium symbiosis model system suggest that the purine metabolic pathway plays a key role in microbe–plant interactions, although the exact mechanism is unknown. Here, we report the impact of a key purine metabolic gene, purL, on the symbiotic interaction between the bacterium Photorhabdus temperata and its nematode partner Heterorhabditis bacteriophora. Real-time PCR assays showed that the purL gene was upregulated in P. temperata in the nematode infective juvenile compared with artificial media. Mutation of the purL gene by in-frame deletion dramatically decreased the capacity of the bacterium to persist in infective juveniles and its ability to form biofilm in vitro. It was further demonstrated that purL gene expression was positively related to bacterial biofilm formation and the symbiotic persistence of the bacterium in nematode infective juveniles. A ΔpurL mutant lost the ability to support infective juvenile formation in the media which weakly supported biofilm formation, suggesting that a critical level of biofilm formation is required by the bacteria to support infective juvenile formation and thus establish their partnership. In addition, the defects in both biofilm formation and symbiotic ability due to the disruption of the purL gene could be partially restored by the addition of 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), an intermediate of the purine biosynthesis pathway. Overall, these data indicate that the purine metabolic pathway is important in microbe–animal symbioses, and that it may influence symbiotic interactions at the level of biofilm formation.

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Proximate and ultimate controls on carbon and nutrient dynamics of small agricultural catchments

Biogeosciences ◽

10.5194/bg-13-1863-2016 ◽

2016 ◽

Vol 13 (6) ◽

pp. 1863-1875 ◽

Cited By ~ 37

Author(s):

Zahra Thomas ◽

Benjamin W. Abbott ◽

Olivier Troccaz ◽

Jacques Baudry ◽

Gilles Pinay

Keyword(s):

Water Quality ◽

Organic Carbon ◽

Dissolved Organic Carbon ◽

Water Chemistry ◽

Human Disturbance ◽

Nutrient Dynamics ◽

Agricultural Activity ◽

Agricultural Catchments ◽

The Impact ◽

The Relationship

Abstract. Direct and indirect effects from human activity have dramatically increased nutrient loading to aquatic inland and estuarine ecosystems. Despite an abundance of studies investigating the impact of agricultural activity on water quality, our understanding of what determines the capacity of a watershed to remove or retain nutrients remains limited. The goal of this study was to identify proximate and ultimate controls on dissolved organic carbon and nutrient dynamics in small agricultural catchments by investigating the relationship between catchment characteristics, stream discharge, and water chemistry. We analyzed a 5-year, high-frequency water chemistry data set from three catchments in western France ranging from 2.3 to 10.8 km2. The relationship between hydrology and solute concentrations differed between the three catchments and was associated with hedgerow density, agricultural activity, and geology. The catchment with thicker soil and higher surface roughness had relatively invariant carbon and nutrient chemistry across hydrologic conditions, indicating high resilience to human disturbance. Conversely, the catchments with smoother, thinner soils responded to both intra- and interannual hydrologic variation with high concentrations of phosphate (PO43−) and ammonium (NH4+) in streams during low flow conditions and strong increases in dissolved organic carbon (DOC), sediment, and particulate organic matter during high flows. Despite contrasting agricultural activity between catchments, the physical context (geology, topography, and land-use configuration) appeared to be the most important determinant of catchment solute dynamics based on principle components analysis. The influence of geology and accompanying topographic and geomorphological factors on water quality was both direct and indirect because the distribution of agricultural activity in these catchments is largely a consequence of the geologic and topographic context. This link between inherent catchment buffering capacity and the probability of human disturbance provides a useful perspective for evaluating vulnerability of aquatic ecosystems and for managing systems to maintain agricultural production while minimizing leakage of nutrients.

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Pruning from spheroidal to cubic canopy induced aphid outbreak by altering the plant performance in Box tree

10.21203/rs.3.rs-45207/v1 ◽

2020 ◽

Author(s):

Anqun Chen ◽

Yinzhan Liu ◽

Xiaolin Liu ◽

Juan Xuan ◽

Chunlian Qiao ◽

...

Keyword(s):

Structural Equation ◽

Field Experiments ◽

Plant Morphology ◽

Dry Mass ◽

Plant Performance ◽

Plant Interactions ◽

Mass Content ◽

Leaf Dry Mass ◽

The Impact ◽

Aphid Abundance

Abstract Backgrounds: Plant-animal interactions comprise the fundamental relationships of ecological research, and are sensitive to environmental change. However, The effects of pruning on animal-plant interactions have rarely been studied. Methods: We conducted field experiments to examine the impact of artificially-pruned shapes (e.g. cubic and spheroidal canopy) on the performance of the Box tree and the resulting aphid abundance at three sites; on a university campus, at a road green belt, and in a residential area. The differences of aphid abundance and plant morphology were determined with ANOVAs and paired-sample tests. Relationships between the investigated parameters were detected with simple regression and structural equation modelResult: Abundance was higher in plants with a cubic canopy than with a spheroidal canopy. Plants with a cubic canopy had lower leaf dry mass content and inflorescence numbers, but greater fresh twig length than the plants with a spheroidal canopy. The aphid abundance was negatively correlated with the leaf dry mass content and inflorescence numbers, and positively correlated with the fresh twig length. Conclusion: Our findings have proven that pruning shape can significantly affect the abundance of herbivores on the pruned plants. The results can provide data support for human actives can alter plant performance, and thereby to change insect preference.

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Extending Uncertainty Analysis of a Hydrodynamic-Water Quality Modelling System using High Level Architecture (HLA)

Water Quality Research Journal ◽

10.2166/wqrj.2005.005 ◽

2005 ◽

Vol 40 (1) ◽

pp. 59-70 ◽

Cited By ~ 3

Author(s):

Karl-Erich Lindenschmidt ◽

Jan Rauberg ◽

Fred B. Hesser

Keyword(s):

Water Quality ◽

Uncertainty Analysis ◽

Computer Architecture ◽

Nutrient Dynamics ◽

Simulation Software ◽

Quality Analysis ◽

High Level Architecture ◽

Quality Model ◽

High Level ◽

The Impact

Abstract This paper illustrates the coupling of water quality model components in High Level Architecture (HLA), a computer architecture for constructing distributed simulations. HLA facilitates interoperability among different simulations and simulation types and promotes reuse of simulation software modules. It was originally developed for military applications but the platform is finding increasing applicability for civilian purposes. The models from the Water Quality Analysis Simulation Program (WASP5) were implemented in HLA to extend its Monte Carlo uncertainty analysis capabilities. The models include DYNHYD (hydrodynamics), EUTRO (phytoplankton and nutrient dynamics) and TOXI (sediment and micropollutant transport). The uncertainty analysis investigated the impact of errors in the hydrodynamic parameters (weir discharge and roughness coefficients) and boundary conditions (upstream and tributary discharge) on the uncertainty in the water quality output variables. It was found that the contribution of the hydrodynamic parameter error to the water quality output uncertainty is comparable to that obtained from the error in the water quality parameters. The error in the boundary condition input data is also an important contributor to model uncertainty.

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