Ecosystem Parameters Research Articles

The effects of temperature on shallow borehole NMR measurements in permafrost

High fidelity observations of the amount and state of water within permafrost help constrain the seasonal behavior of soil moisture and the effects of soil moisture on the surface energy balance. This work emphasizes the necessity for temperature-specific calibrations of low-frequency borehole NMR measurements. Constraining the effects of temperature on NMR signatures will allow for more reliable NMR inspection of hydrogeochemical parameters in permafrost ecosystems. We find that calibration at typical laboratory temperatures (20 °C) and subsequent measurement at typical permafrost active layer temperatures (∼0 °C) can result in an 18% bias in reported NMR water content values, and therefore temperature compensation is required under most scenarios. This is particularly important for active layer conditions that may include steep vertical temperature gradients. Similarly, seasonal time-lapse measurements of permafrost active layer may encounter substantial soil temperature variations which would also require temperature compensation on the observed NMR water content estimate.

Modelling impacts of climate change and anthropogenic activities on inflows and sediment loads of wetlands: case study of the Anzali wetland

Understanding the effects of climate change and anthropogenic activities on the hydrogeomorpholgical parameters in wetlands ecosystems is vital for designing effective environmental protection and control protocols for these natural capitals. This study develops methodological approach to model the streamflow and sediment inputs to wetlands under the combined effects of climate and land use / land cover (LULC) changes using the Soil and Water Assessment Tool (SWAT). The precipitation and temperature data from General Circulation Models (GCMs) for different Shared Socio-economic Pathway (SSP) scenarios (i.e., SSP1-2.6, SSP2-4.5, and SSP5-8.5) are downscaled and bias-corrected with Euclidean distance method and quantile delta mapping (QDM) for the case of the Anzali wetland watershed (AWW) in Iran. The Land Change Modeler (LCM) is adopted to project the future LULC at the AWW. The results indicate that the precipitation and air temperature across the AWW will decrease and increase, respectively, under the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios. Streamflow and sediment loads will reduce under the sole influence of SSP2-4.5 and SSP5-8.5 climate scenarios. An increase in sediment load and inflow was observed under the combined effects of climate and LULC changes, this is mainly due to the projected increased deforestation and urbanization across the AWW. The findings suggest that the densely vegetated regions, mainly located in the zones with steep slope, significantly prevents large sediment load and high streamflow input to the AWW. Under the combined effects of the climate and LULC changes, by 2100, the projected total sediment input to the wetland will reach 22.66, 20.83, and 19.93 million tons under SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios, respectively. The results highlight that without any robust environmental interventions, the large sediment inputs will significantly degrade the Anzali wetland ecosystem and partly-fill the wetland basin, resulting in resigning the wetland from the Montreux record list and the Ramsar Convention on Wetlands of International Importance.

Effect of land preparation methods on restoration success of degraded oak forest ecosystems

Estimation of the success of ecosystem restoration through different methods is essential of planning restoration projects, especially nowadays when the world community has declared the target for an effective restoration of 25% of degraded ecosystems in the next years. In the present study, we intro­duce the results of the application of two land preparation methods – soil ripping and land terracing - on ecosystem restoration success twenty years after restoration actions. The study concerns two reforested areas with the species Quercus pubescens, a deciduous oak species. In both reforested areas an estimation of the ecological conditions was carried out as well as stand growth and volume data, based on the following field measurements: soil fertility data, vegetation analysis, tree morphological characteristics, and tree vol­umetric characteristics. The analysis of the results showed that the land preparation method “soil ripping”, greatly improved all the studied ecosystem parameters as well as oak stand characteristics, comparing to the “terracing” method. More specifically, it improved the physical and chemical properties of the soils, the coverage and the composition of flora species, and enhanced the existence of more woody species. It privi­leged the growth of Quercus pubescens trees contributing to a higher stand volume.

Phytoremediation, bioaccessibility and ecotoxicological risk assessment of arsenic in a gold mining area

The physicochemical and biological parameters of aquatic ecosystems are directly affected by mining activities, increasing the ecotoxicological risk related to exposure to contaminants and pollutants. In this study, a native and adapted floating aquatic macrophyte was used in a gold mining area as a model organism to assess the environmental risk and its potential application in bioremediation of heavy metals. The physicochemical parameters of water and sediments were evaluated, as well as the phytoremediation parameters (bioconcentration and translocation factors) of Hydrocotyle ranunculoides L. The results showed a significant bioconcentration of Cr, Pb, Cu, and Zn in the roots of the macrophyte (high BCF: As > Cu > Zn > Pb > Cr), confirming its suitability for use in rhizofiltration. Regarding arsenic bioconcentration, H. ranunculoides demonstrated a high BCF and TF > 1, indicating its phytoextraction potential, an essential requirement for plants to be used in bioremediation programs.

ВОЗМОЖНЫЕ СЦЕНАРИИ ФОРМИРОВАНИЯ МАТЕРИКОВОГО СТОКА И СОЛЕНОСТИ ВОД АЗОВСКОГО МОРЯ С УЧЕТОМ СОВРЕМЕННЫХ И ПЕРСПЕКТИВНЫХ ТЕНДЕНЦИЙ ИЗМЕНЕНИЯ КЛИМАТА

Introduction. The ongoing climate changes have a significant impact on the formation of the habitat conditions for the aquatic biological resources of the Azov Sea. Salinity of the Azov Sea waters and continental runoff, which role in maintaining the ecological well-being of the habitat of aquatic biological resources is paramount, has underwent particularly noticeable transformations. Relevance. Assessment of the degree of influence of ongoing and expected climate changes on the formation of abiotic parameters of the marine ecosystem is a prerequisite for planning the successful development of the fisheries industry of the Azov Sea Basin. The aim of this work is to assess the current and expected changes in the hydrometeorological parameters of the Azov Sea ecosystem, as well as to identify the most probable scenarios of changes in the Azov Sea salinity depending on the annual volume of continental runoff. Methods. The study is based on the data from AzNIIRKH database for the time range 1960–2020 collected over the course of the expedition surveys examining the Azov Sea hydrological regime and the data of the reference observation network of the Russian Federal Service for Hydrometeorology and Environmental Monitoring (Roshydromet). Methods of mathematical statistics, graphoanalytical construction, mapping and analogy have been used for the data analysis. Results. This paper assesses the changes in the hydrological regime of the Azov Sea based on the annual monitoring of the habitat of aquatic biological resources. Preliminary calculations have been performed, and new data on the changes in the parameters of the sea water balance equation not covered by monitoring over the past forty-five years have been presented. The most probable formation scenarios for the continental runoff and the Azov Sea water salinity for the future up to 2030 are considered, with the observed trend of climate warming taken into account. Conclusions. Both the climatic and anthropogenic factors have contributed to considerable changes in the current hydrometeorological regime of the Azov Sea. These changes have mainly been manifested in an increase in air and water temperatures, a decrease in wind activity, and in a reduced continental runoff, in the formation of which, since 2006, a prolonged low water content cycle has been observed. The shortage of river runoff and increased water evaporation rate, along with other factors, have induced an unprecedented increase in the Azov Sea salinity, the average annual value of which in 2021 reached a record high (14.97 %). In the most probable scenario (60 %) with the continuation of the low water content period and the continental runoff into the Azov Sea of about 22 km3 in volume, the average annual salinity of the Azov Sea, including Taganrog Bay, can reach 15±0.40 ‰ with a variation range from 14.5 to 16.5 ‰ in the sea itself (excluding Taganrog Bay). 2021 can serve as an analogous year in terms of salinity formation and its spatial distribution.

Influence of GEDI Acquisition and Processing Parameters on Canopy Height Estimates over Tropical Forests

LiDAR technology has been widely used to characterize structural parameters of forest ecosystems, which in turn are valuable information for forest monitoring. GEDI is a spaceborne LiDAR system specifically designed to measure vegetation’s vertical structure, and it has been acquiring waveforms on a global scale since April 2019. In particular, canopy height is an important descriptor of forest ecosystems, as it allows for quantifying biomass and other inventory information. This paper analyzes the accuracy of canopy height estimates from GEDI data over tropical forests in French Guiana and Gabon. The influence of various signal acquisition and processing parameters is assessed to highlight how they impact the estimation of canopy heights. Canopy height models derived from airborne LiDAR data are used as reference heights. Several linear and non-linear approaches are tested given the richness of the available GEDI information. The results show that the use of regression models built on multiple GEDI metrics allows for reaching improved accuracies compared to a direct estimation from a single GEDI height metric. In a notable way, random forest improves the canopy height estimation accuracy by almost 80% (in terms of RMSE) compared to the use of rh_95 as a direct proxy of canopy height. Additionally, convolutional neural networks calibrated on GEDI waveforms exhibit similar results to the ones of other regression models. Beam type as well as beam sensitivity, which are related to laser penetration, appear as parameters of major influence on the data derived from GEDI waveforms and used as input for canopy height estimation. Therefore, we recommend the use of only power and high-sensitivity beams when sufficient data are available. Finally, we note that regression models trained on reference data can be transferred across study sites that share identical environmental conditions.

On Theoretical Foundations of Aerolimnology: Study of Fresh Water Bodies and Coastal Territories Using Air Robot Equipment

The integration of the methodological basis of several different sciences in interdisciplinary research is a characteristic feature of new mechanisms for solving modern applied problems. The emerging theoretical foundations of aerolimnology, as a new scientific direction, are considered from the point of view of the contribution of three key sciences to it: limnology, informatics and robotics. Classifications of methods and approaches of limnological research, airborne robotic means, and information technologies that are promising for solving problems in the field of aerolimnology are given. The task of the scientific direction of aerolimnology is formulated as the study of the possibilities and limitations of combined methods of remote sensory measurement, robotic sampling and analytical study of the parameters of freshwater ecosystems to monitor and predict the dynamics of their development. Among the main areas of aerolimnological research, the following are distinguished: the construction of orthophotomaps and photogrammetric spatial models of the bottom topography and individual elements of the bottom landscape and coastal zone of various scales; geological and geophysical mapping of the underwater part of the coastal zone; the study of phytoplankton, in particular, the "bloom" of water caused by cyanobacteria; study of distribution and migration of large representatives of hydrofauna; study of temperature fields and processes of redistribution of water masses. The limitations imposed on the use of unmanned aerial vehicles (UAVs) in sampling and monitoring coastal water areas are discussed, primarily weather-climatic, temporal, spatial, and technical. The advantage of using unmanned aerial vehicles in aerolimnology is justified by an increase in the speed of data acquisition, the possibility of approaching hard-to-reach and territorially remote objects, and a decrease in the influence of the human factor. The scientific novelty of the presented research consists in an attempt to integrate interdisciplinary knowledge when using unmanned aerial vehicles and processing the obtained data based on artificial intelligence technologies in the study of limnological objects and processes. The important role of geoinformation systems is noted and examples of maps of shore typification and geomorphology of Lake Ladoga are given, posted on the website of the Center for the Collective Use of Scientific Equipment "North-Western Center for Monitoring and Forecasting the Development of Territories" of the St. Petersburg Federal Research Center of the Russian Academy of Sciences. The main stages of the methodology for conducting aerolimnological studies using interdisciplinary approaches based on limnology, informatics and robotic tools operating in different environments are considered.

Soil Fungal Composition Drives Ecosystem Multifunctionality after Long-Term Field Nitrogen and Phosphorus Addition in Alpine Meadows on the Tibetan Plateau.

An ecosystem can provide multiple functions and services at the same time, i.e., ecosystem multifunctionality (EMF). Above- and belowground biodiversity and abiotic factors have different effects on EMF. Human activities increase atmospheric nitrogen (N) and phosphorus (P) deposition, but the mechanism of how atmospheric N and P deposition affect EMF in alpine meadows on the Tibetan Plateau is still unclear. Here, we measured eleven ecosystem parameters to quantify EMF by averaging method and explored the impact of plant and microbial species diversity and abiotic factors on EMF after long-term field N and P addition in alpine meadows on the Tibetan Plateau. Results showed that N addition reduced EMF by 15%, NP increased EMF by 20%, and there was no change due to P addition. N and P addition reduced pH, relative light conditions (RLC), and plant species richness and modified plant and fungal community composition. Structural equation model (SEM) analysis confirmed that fungal community composition was an important and positive driver on EMF. These results provided an understanding of how N and P addition affect EMF directly and indirectly through biotic and abiotic pathways, which was important for predicting the response of EMF to atmospheric N and P deposition in the future. Furthermore, the findings suggested that soil fungal composition was more important driving factors than abiotic factors in the response of EMF to N and P addition and the importance of the interactions between plant and soil microbial species diversity in supporting greater EMF.

Litter, Plant Competition, and Ecosystem Dynamics: A Theoretical Perspective.

AbstractCommunity structure depends jointly on species' responses to, and effects on, environmental factors. Many such factors, including detritus, are studied in ecosystem ecology. Detritus in terrestrial ecosystems is dominated by plant litter (nonliving organic material), which, in addition to its role in material cycling, can act as a niche factor modulating interactions among plants. Litter thus links traditional community and ecosystem processes, which are often studied separately. We explore this connection using population dynamics models of two plant species and a litter pool. We first find conditions determining the outcome of interactions between these species, highlighting the role that litter plays and the role of broader ecosystem parameters, such as decomposition rate. Species trade-offs in tolerance to direct competition and litter-based interference competition allow for coexistence, provided the litter-tolerant species produces more litter at the population level; otherwise, priority effects may result. When species coexist, litter-mediated interactions between plants disrupt the traditional relationship between biomass accumulation and decomposition. Increasing decomposition rate may have no effect on standing litter density and, in some cases, may even increase litter load. These results illustrate how ecosystem variables can influence community outcomes that then feed back to influence the ecosystem.

Advancing parameter estimation with Characteristic Finite Difference Method (CFDM) for a marine ecosystem model by assimilating satellite observations: Spatial distributions

The ecosystem parameters are critical for precisely determining the marine ecological process and improving the simulations of the marine ecological model. In this study, based on the NPZD (nutrient, phytoplankton, zooplankton and detritus) model, the surface chlorophyll-a observations obtained from Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data were assimilated to estimate spatially ecosystem parameters in the Bohai, Yellow, and East China Seas using an adjoint assimilation method with characteristic finite difference scheme. The experiments of the moving Gaussian hump indicated that the characteristic finite difference method (CFDM) can get rid of the limit of stability and permit using large time steps, which reduces long computation durations and large memory requirements. The model performance was significantly improved after data assimilation with CFDM using a large time step of 6 hours. Moreover, the distributions of parameters of the NPZD model in winter in the Bohai Sea, the Yellow Sea, and the East China Sea were simulated by our method. Overall, the developed method can efficiently optimize the ecosystem parameters and the results can be beneficial for determining reasonable parameters of the marine ecological model.

Single-cell view of deep-sea microbial activity and intracommunity heterogeneity.

Microbial activity in the deep sea is cumulatively important for global elemental cycling yet is difficult to quantify and characterize due to low cell density and slow growth. Here, we investigated microbial activity off the California coast, 50-4000 m water depth, using sensitive single-cell measurements of stable-isotope uptake and nucleic acid sequencing. We observed the highest yet reported proportion of active cells in the bathypelagic (up to 78%) and calculated that deep-sea cells (200-4000 m) are responsible for up to 34% of total microbial biomass synthesis in the water column. More cells assimilated nitrogen derived from amino acids than ammonium, and at higher rates. Nitrogen was assimilated preferentially to carbon from amino acids in surface waters, while the reverse was true at depth. We introduce and apply the Gini coefficient, an established equality metric in economics, to quantify intracommunity heterogeneity in microbial anabolic activity. We found that heterogeneity increased with water depth, suggesting a minority of cells contribute disproportionately to total activity in the deep sea. This observation was supported by higher RNA/DNA ratios for low abundance taxa at depth. Intracommunity activity heterogeneity is a fundamental and rarely measured ecosystem parameter and may have implications for community function and resilience.

Seasonal Variability of Phytoplanktons in the Non-Point Source Polluted River Nggada, Maiduguri – Borno State, Nigeria

Borno State is the epicenter of Boko Haram crisis which displaced millions of individuals. Maiduguri metropolis which became the principal refuge centre, has witnessed a rapid demographic change, land use and economic activities resulting into intense irrigational practice along the bank of river Nggada. This may result into changes in the physico – chemical parameters of the aquatic ecosystem and the dynamism may disrupt phytoplantonic community. The study was aimed at assessing the seasonal variability of phytoplanktons in non-point source polluted river Nggada of Maiduguri. Water samples for physico -chemical analysis were collected bi-weekly for a period of 11 months at three sampling stations. Physico-chemical parameters, including Dissolve Oxygen (DO), Dissolved Nitrate concentration, Dissolved Phosphorus Concentration, Total Dissolved Solids (TDS), Total Suspended Solids (TSS), Surface Water Temperature (SWT) and potential Hydrogen (pH) were determined using standard procedures. Results indicated that all physico – chemical parameters except temperature, DO and pH of the river during both irrigational and non-irrigational regimes were slightly above the National Environmental Standards and Regulations Enforcement Agency’s (NESREA) permissible limits. A total of 7 classes (Cyanophyceae Chlorophyceae, Cryptophyceace, Euglenophyceae, Bacillariophyceae, Crysophyceace and Rhodophyceae) and 16 genera of phytoplanktons were identified. The results further revealed that the irrigation activities (dry season) have impacted on the physico – chemical parameters (pH, DO, TDS, nitrate and phosphate concentrations) of the study area. Remarkably, the changes in the physico – chemical parameters during the irrigational regime (dry season) have not impacted on the abundance and distribution of phytoplanktons. Hence, the non-point pollutants influenced the physico – chemical parameters of the river butalgal abundance and distribution were not influenced by the changes in the physico – chemical parameters of the river. The study thus, recommends the continuous monitoring and systematic effort to conserve the bio-resources and water quality of the river

A modified habitat quality model to incorporate the effects of ecological restoration

Ecosystem restoration has the potential to improve the ecological environment, increase ecosystem service delivery capability, and promote biodiversity conservation. Although habitat quality (HQ) is being widely used as a metric for large-scale biodiversity conservation, it is poorly understood and measured in areas with significant vegetation restoration (VR). This study proposes a modified approach based on the InVEST-HQ module by coupling Normalized Difference Vegetation Index to measure the HQ in the Yellow River Basin (YRB) with extensive VR in recent decades. The results show that the VR area with significant increases in both Leaf Area Index and net primary production accounts for 29.7% of the total area of the YRB. The original and modified modules were compared. Based on the InVEST-HQ module, the results show that HQ has a tendency for very small changes in the years 2000, 2010, and 2020, with first a small increase and then a small decrease; however, HQ based on the modified method has a significantly increasing trend, which is consistent with the ecological restoration status of the study area and the trend of key ecosystem parameters. The modified method effectively expresses HQ changes with VR, making it more appropriate for usage in areas where nature conservation and ecosystem restoration are important management actions, allowing for realistic decision-making and data support for regional biodiversity conservation and habitat management.

Functional ecosystem parameters: Soil respiration and diversity of mite (Acari, Mesostigmata) communities after disturbance in a Late Cambrian bedrock environment

AbstractWe analyzed the changes in ecosystem functions (soil respiration and Mesostigmata mite abundance, species richness and diversity) on various habitats after flooding by highly mineralized and acidic drainage water with fine As‐rich pyrite sediments, on a fragment of a natural ecosystem. In total, 177 plots that represented six types of habitats (undisturbed: pine mixed forests, Salix spp. thickets, Juncus effusus communities, wet meadows, and disturbed: bare ground and dead Salix spp. thickets) were sampled twice, in June 2019 and September 2020. Our study revealed that flooding affected essential ecosystem parameters, such as soil Mesostigmata mite abundance, species richness and diversity, and soil respiration, via an extreme decrease of soil pH. In total, 968 mites were collected from pooled data from the two samplings. Mite abundance, species richness and diversity were mainly shaped by habitat type and soil pH, and partially by soil respiration. These parameters were lower in disturbed habitats (bare ground and dead Salix spp. thickets) as compared with undisturbed ones. The highest mean mite density was recorded from mixed forests (4750 ± 600 ind. m−2) and wet meadows (2678 ± 361 ind. m−2), whereas the lowest in bare ground (449 ± 113 ind. m−2) and dead Salix spp. thickets (537 ± 146 ind. m−2). We noticed that mite diversity may be helpful to predict future changes in the physicochemical parameters of soils in disturbed areas. The vegetation patches built up by species adapted to grow in habitats characterized by relatively high metal and metalloid content (J. effusus and Salix spp.) represent an intermediate state of function of ecosystems in the study area.

Plankton Planet: A frugal, cooperative measure of aquatic life at the planetary scale

In every liter of seawater there are between 10 and 100 billion life forms, mostly invisible, called marine plankton or marine microbiome, which form the largest and most dynamic ecosystem on our planet, at the heart of global ecological and economic processes. While physical and chemical parameters of planktonic ecosystems are fairly well measured and modeled at the planetary scale, biological data are still scarce due to the extreme cost and relative inflexibility of the classical vessels and instruments used to explore marine biodiversity. Here we introduce ‘Plankton Planet’, an initiative whose goal is to engage the curiosity and creativity of researchers, makers, and mariners to (i) co-develop a new generation of cost-effective (frugal) universal scientific instrumentation to measure the genetic and morphological diversity of marine microbiomes in context, (ii) organize their systematic deployment through coastal or open ocean communities of sea-users/farers, to generate uniform plankton data across global and long-term spatio-temporal scales, and (iii) setup tools to flow the data without embargo into public and explorable databases. As proof-of-concept, we show how 20 crews of sailors were able to sample plankton biomass from the world surface ocean in a single year, generating the first seatizen-based, planetary dataset of marine plankton biodiversity based on DNA barcodes. The quality of this dataset is comparable to that generated by Tara Oceans and is not biased by the multiplication of samplers. The data unveil significant genetic novelty and can be used to explore the taxonomic and ecological diversity of plankton at both regional and global scales. This pilot project paves the way for construction of a miniaturized, modular, evolvable, affordable and open-source citizen field-platform that will allow systematic assessment of the eco/morpho/genetic variation of aquatic ecosystems and microbiomes across the dimensions of the Earth system.

Mineralogic controls are harbingers of hydrological controls on soil organic matter content in warmer boreal forests

Boreal forests contain ∼ 30 % of the global forest soil organic carbon (SOC) stock within a region vulnerable to climate change, yet regional studies on the climate relevant controls of this large reservoir are lacking. The Newfoundland and Labrador Boreal Ecosystem Latitudinal Transect represents a boreal climate gradient of sites ranging in temperature and precipitation similar in extent to changes expected within the region over the next century. Though forest and soil type are similar across the transect, geological parent material upon which soils have developed vary across the region. Despite a > 50 % increase in litterfall and a 3-fold increase in the dissolved organic matter inputs to the mineral soil with decreasing latitude, average surface horizon mineral SOC and N content are similar among regions. To explain this, the relationships between mineral soil characteristics and other ecosystem parameters with SOC and N content were assessed using an information theoretic approach to rank models. Rankings were used to determine the most relevant variables explaining regional variance in surface mineral SOC. Unsurprisingly, organo-metal complexes (OMCs), a weathering product, were a major component of all plausible models. However, Al complexes ranked higher than Fe, likely because of the greater solubility of reduced Fe in reducing microsites, particularly beneath the winter snowpack or within the saturated soils during the spring melt. These results highlight the potential role of seasonal hydrology on the formation of metal-stabilized C and N in boreal forests and suggest that the role of Fe OMC in C sequestration may be enhanced with warmer winters. The realization and effect of these seasonally controlled OMC mechanisms require further understanding of mineral soil characteristics and hydrology and their response to climate warming. Such efforts will improve predictions of the impact of climate change on soil C and N content in these forests.

Assessment of National Innovation Ecosystems of the EU Countries and Ukraine in the Interests of Their Sustainable Development

The purpose of the study is to reveal specific features of modern EU innovation policy in the context of its focus on sustainable European development and to conduct an assessment of the parameters of national innovation ecosystems of the EU member states with different innovation potential and Ukraine from the standpoint of their influence on the innovative development of countries worldwide. With the use of the correlation-regression analysis, the hypothesis of changing the parameters of national innovation ecosystems that affect the innovation of the EU member states and Ukraine in the global context depending on the level of their productivity and innovation potential was reiterated. The factors that have the greatest impact on the ranking of the countries in the Global Innovation Index, depending on which group the countries under study belong to according to the classification of the European Innovation Scoreboard, were identified. It was revealed that the set of such factors in each group of countries varies and has a different degree of influence on the level of their innovation development. Based on the results of the assessment, taking into account the need for a speedy post-war reconstruction of Ukraine, policy recommendations were made for Ukraine. Their implementation will ensure the systemic influence of the state on the national innovation ecosystem of the country.

Predicting the effects of multiple global change drivers on microbial communities remains challenging.

Microbial communities in many ecosystems are facing a broad range of global change drivers, such as nutrient enrichment, chemical pollution, and temperature change. These drivers can cause changes in the abundance of taxa, the composition of communities, and the properties of ecosystems. While the influence of single drivers is already described in numerous studies, the effect and predictability of multiple drivers changing simultaneously is still poorly understood. In this study, we used 240 highly replicable oxic/anoxic aquatic lab microcosms and four drivers (fertilizer, glyphosate, metal pollution, antibiotics) in all possible combinations at three different temperatures (20, 24, and 28°C) to shed light into consequences of multiple drivers on different levels of organization, ranging from species abundance to community and ecosystem parameters. We found (i) that at all levels of ecological organization, combinations of drivers can change the biological consequence and direction of effect compared to single drivers, (ii) that effects of combinations are further modified by temperature, (iii) that a larger number of drivers occurring simultaneously is often quite closely related to their effect size, and (iv) that there is little evidence that any of these effects are associated with the level of ecological organization of the state variable. These findings suggest that, at least in this experimental ecosystem approximating a stratified aquatic ecosystem, there may be relatively little scope for predicting the effects of combinations of drivers from the effects of individual drivers, or by accounting for the level of ecological organization in question, though there may be some scope for prediction based on the number of drivers that are occurring simultaneous. A priority, though also a considerable challenge, is to extend such research to consider continuous variation in the magnitude of multiple drivers acting together.

Controls and characteristics of biomass quantization in size-structured planktonic ecosystem models

Strong relationships between size and other traits have long motivated studies of the size structure and dynamics of planktonic food webs. Size structured ecosystem models (SSEMs) are often used to represent the behavior of these ecosystems, with organism size as a first order approximation of the axis of biological diversity. Previous studies using SSEMs have reported the emergence of localized “peaks” in the size spectrum, a phenomenon that will be referred to in this study as “quantization”. However, SSEMs that are used routinely in Earth System Models (ESMs), they tend to be too coarsely discretized to resolve quantization. Observational studies of plankton biomass have also shown qualitatively similar patterns, with localized peaks along the size spectrum. The conditions under which quantization occurs and the ecosystem parameters that control the locations of the biomass “peaks” along the size spectrum have not been systematically explored. This study serves to simultaneously advance our understanding of the constraints on quantization in size-structured ecosystems, and to suggest an approach to discretizing SSEMs that leverages quantization to select a greatly reduced number of size classes. A size-structured model of the pelagic food web, similar to those implemented in global models, is used to investigate the sensitivity of biomass peaks to predator–prey interactions, and nutrient forcing. This study shows that the location of biomass peaks along the size spectrum is strongly controlled by the size selectivity of predation, and the location of biomass peaks along the size spectrum is less sensitive to variations in nutrient supply, external ecosystem forcing, and vertical heterogeneity. Taking advantage of a robust localization of biomass peaks, the dynamics of a continuous planktonic size spectrum to be represented using a few selected size classes, corresponding to locations of the peaks along the size spectrum. These findings offer an insight on how to approach discretization of size structured ecosystem model in Earth system models.

AN INVESTIGATION OF PHYSICOCHEMICAL PARAMETERS AND PHYTOPLANKTON COMMUNITY STRUCTURE OF EKO-NDE RESERVOIR IN OSUN STATE, NIGERIA

This research was carried out to determine the relationship between physicochemical variables and phytoplankton community of the Eko-Nde reservoir. Changes in physicochemical parameters of aquatic ecosystems have significant impact on the species that live therein. Eko-Nde reservoir is of socio-economic significance to communities that surround it, which necessitates a proper study of the phytoplankton composition and environmental status of the reservoir. Water samples were collected from two stations in the reservoir from January 2019 to August 2019. The physicochemical parameters that were determined include but not limited to temperature, total hardness, pH and biochemical oxygen demand. The composition and diversity of phytoplankton were analyzed. A total of 2039 cells ml-1 belonging to four (4) major divisions were dominant in the order; Bacillariophyta (898 cells ml-1) > Charophyta (788 cells ml-1) > Chlorophyta (302 cells ml-1) > Cyanophyta (51 cells ml-1). Principal Component Analysis and Canonical Corresponding Analysis showed that certain physicochemical variables such as temperature, pH and total hardness were key drivers of the phytoplankton community structure of the reservoir. Diversity indices showed moderate abundance and distribution of phytoplankton species, with the highest diversity of species in the months associated with the rainy season. The appearance of pollution tolerant species such as Anabaena circinalis, Oscillatoria limosa, Nitzschia gracilis, Cymbella mexicana, Pediastrum boryanum, Synedra ulna, Cyclotella meneghiniana and Gomphonema spp. suggest that the reservoir was on the verge of pollution. Anthropogenic activities around the reservoir should be closely monitored to avoid health risks to humans and endangerment of aquatic organisms.