Biotic Resource Research Articles

Bacillus velezensis SS-20 as a potential and efficient multifunctional agent in biocontrol, saline-alkaline tolerance, and plant-growth promotion

The versatile strain Bacillus velezensis SS-20 was studied to determine its agricultural benefits, including its ability to antagonize fungi, promote plant growth, and tolerate saline-alkaline conditions. Firstly, strain SS-20 was found to be an antagonist of plant pathogenic fungi such as Magnaporthe oryzae, Rhizoctonia solani, and Fusarium oxysporum, with control effects up to 82.07 %, 46.57 %, and 23.09 %, respectively. The hyphae of pathogenic fungi treated with SS-20 and its fermentation product were abnormal, swollen, deformed, and distorted. Meanwhile, strain SS-20 dissolved inorganic phosphorus (phosphate solubilization efficiency, 45.95 %), and produced siderophore (siderophore units, 54.18 ± 4.19 %), and poly-γ-glutamic acid (γ-PGA) (13.35 ± 2.61 g/L). Strain SS-20 significantly increased plant height, aboveground fresh weight, and root dehydrogenase activity compared to the control treatment under non-saline conditions (p < 0.05). In addition, strain SS-20 showed significant saline-alkaline tolerance, surviving in 10 % NaCl and pH 9.5, and enhanced plant growth under simulated saline-alkali conditions. Whole-genome sequencing analysis revealed that the chromosome of B. velezensis SS-20 consists of 3,929,792-bp with 46.5 % guanine-cytosine content and 4015 coding sequences. The antiSMASH analysis identified 12 gene clusters within strain SS-20 that encode antimicrobial compounds such as surfactin, fengycin, butirosin A/butirosin B, macrolactin H, bacillibactin, difficidin, and bacilysin, thereby corroborating the strain's biocontrol capabilities. Genes related to plant growth promotion, including siderophores, γ-PGA, indole acetic acid production, phosphate solubilization, glycine-betaine production, and Na+/H+ antiporters, were also annotated. In conclusion, B. velezensis SS-20 represents a promising biotic resource for enhancing plant growth and protecting against environmental stresses.

A diffusive intraguild predation model with variable-carrying capacity proportional to the same biotic resource

A diffusive intraguild predation model with variable-carrying capacity proportional to the same biotic resource

Self-organized biodiversity in biotic resource systems through pairwise encounters

A central issue in ecology is understanding what determines biodiversity in nature, particularly in biotic resource systems that typically lack cross-feeding. In this study, we demonstrate that by incorporating pairwise encounters among individuals of the same consumer species, a diverse array of consumer species can self-organize to coexist in a well-mixed system with one or a few biotic resource species. The coexistence modes may manifest as either stable steady states or self-organized oscillations. Notably, all coexistence states are robust to stochasticity, as confirmed by both stochastic simulation algorithms and individual-based modeling. Our model quantitatively illustrates species distribution patterns in various ecological communities and can be broadly used to explain biodiversity in many biotic resource systems.

Spatial–Temporal Evolution Characteristics and Driving Mechanism Analysis of the “Three-Zone Space” in China’s Ili River Basin

The Ili River Basin (IRB) is located in the northwest of China. With its large-scale zone and abundant resources, it is believed to be a “wet island” and a biotic resource storehouse in the dry regions of Eurasia. The IRB has stable ecological conditions and abundant water resources, providing natural conditions for agricultural production and human settlements. With the population increasing and economic development advancing, the competition for land resources is becoming fierce, leading to some ecological problems in this region. Therefore, understanding the spatiotemporal changes and driving mechanisms of the “three-zone space” (TZS) in the IRB is of significant practical importance for promoting sustainable development and optimizing the territorial spatial pattern. This study first analyzes the characteristics and intensity of the TZS changes from 2000 to 2020. Then, it utilizes the optimized parameter Geodetector (OPGD) to analyze the driving mechanisms behind these changes. The results show the following. Firstly, the agricultural space (AS) increased by a total of 837.5 km2, the urban space (US) increased by 519.64 km2, and other ecological space (OES) increased by 1518.83 km2. Green ecological space (GES) decreased by 2875.97 km2. Secondly, intensity analysis indicated that the total TZS change in IRB was 11.07%. At the spatial-type level, the increased intensities of OES, US, and AS were active. In spatial transformation intensity, US and OES tended to transform into AS; AS tended to transform into US; and OES and GES had a mutual transformation tendency. Thirdly, AS converted into US around emerging cities like Khorgas and Cocodala. The conversion towards GES was scattered. The mutual conversion between OES and GES showed spatial distribution consistency, mainly occurring in the Borohoro ranges and the Halik ranges. Lastly, regarding the driving mechanisms, the evolution of US in the IRB was driven by social and economic factors. Location and climate factors accelerated agricultural development, facilitating the transformation of GES and OES into AS. Climate and economic factors played a crucial role in the scale of conversions between OES and GES. The findings can provide a basis for the governance and protection of the IRB, help to form a rational territorial spatial pattern, and offer scientific guidance for sustainable land management.

Towards cleaner environment: recycling microalgal co-product to reduce emissions and impacts while eliminating fishmeal in rainbow trout feed for sustainable aquaculture

The rapid increase in aquaculture over the last several decades has led to concerns about the environmental impact of fish feeds relying on marine resources for fishmeal (FM). We aim to assess Nannochloropsis sp. QH25 co-product as a viable and sustainable replacement for FM in juvenile rainbow trout, Oncorhynchus mykiss, feeds. We formulated four experimental diets: a reference (FM based), 33N, 66N, and 100N diet (33%, 66%, and 100% co-product replacement). Rainbow trout were randomly assigned to one of 16 tanks and randomly assigned an experimental diet to consume throughout the experiment (64 days total), with four replicate tanks per diet. We compared the phosphorus (P) and nitrogen (N) digestibility, emissions, and growth between diets and, compared six environmental impacts (biotic resource use (BRU), global warming potential (GWP), water use, land use, marine eutrophication potential (MEP), and freshwater eutrophication potential (FEP)) of each diet. Our results indicate that replacing FM with co-product did not significantly alter growth. P digestibility of the experimental and reference diets was comparable. BRU conversion ratio was significantly lower in the experimental diets. However, there were significantly higher water and land use conversion ratios but insignificantly higher results in GWP, MEP, and FEP between the reference and 100N diet.

Fisheries Impact Pathway: Making Global and Regionalised Impacts on Marine Ecosystem Quality Accessible in Life Cycle Impact Assessment

Fisheries Impact Pathway: Making Global and Regionalised Impacts on Marine Ecosystem Quality Accessible in Life Cycle Impact Assessment

Evolving environmental awareness and shifts in management priorities: a socioeconomic lens on the min river basin, China

Watersheds have experienced economic and demographic development for decades. In China, this development has been associated with environmental degradation, including water quality deterioration, abnormal stream flow, and biotic resource depletion. Effective watershed management incorporates sustainability and public involvement, enabling the long-term security of the human and natural world. Management strategies however need to take into account local conditions, as every watershed is unique. This paper adopts the analytic hierarchy process (AHP) combined with the random forest model to investigate the shift in participants’ environmental awareness across different socioeconomic groups over the past 15 years. Additionally, it scrutinizes the changing public perceptions on the management priorities and areas requiring enhancement. The AHP index highlighted the importance of environmental behavioral intentions (EBI) as a component of environmental awareness (EA). Between 2006 and 2021, significant changes occurred in public environmental awareness (perception, knowledge, behavioral intention) and perceived management priorities, stressing the need for timely adjustment of management policies. Notably, environmental concern (EC) appears to have decreased over time, reflecting effective management and increased governmental attention. Emphasis on the recreational ecosystem services offered by watershed forests has increased. Males, individuals aged over 40-years-old, and individuals located in the upper reaches possessed higher risk perceptions than other groups. These findings may help policymakers to adjust management priorities based on geographic region and may assist them in promoting more effective measures to communicate watershed sustainable management goals and strategies to the public.

Facets of functional diversity support niche‐based explanations for Australian biodiversity gradients

AbstractAimThere is widespread support that species richness increases with the available energy of an ecosystem, but the mechanisms underlying this driver of biodiversity patterns remain elusive. We evaluated gradients of functional diversity to test whether the higher species richness of productive, structurally diverse environments is due to a greater range of niches being supported by the abiotic conditions present (environmental filtering), greater availability of biotic resource and habitat niches (more niches) or increasing functional similarity of species (niche packing).LocationAustralia.TaxonBirds and mammals.MethodsWe used structural equation modelling to evaluate the relative contributions of climatic harshness (actual evapotranspiration, AET) and the availability of resource (gross primary productivity, GPP) and habitat (tree height) niches on taxonomic richness and functional richness, dispersion and evenness. We performed parallel analyses within 15 bioclimatic zones and continentally to evaluate the scaling of biodiversity gradients and the shifting balance between niche‐based mechanisms along environmental gradients.ResultsAll continental diversity gradients were primarily associated with energy variables, but while species richness of both taxa and all functional diversity measures of bird assemblages increased with AET, mammal functional diversity was more strongly associated with GPP gradients. Results were more variable at the regional scale, but species richness gradients along tree height (birds and mammals) and GPP (mammals) within bioclimatic zones tended not to be paralleled by increases in functional richness or dispersion.Main ConclusionsThe niche‐based explanations of biodiversity gradients varied in importance with scale, position on environmental gradients and taxonomic group. At the continental extent, bird biodiversity gradients were structured by environmental filtering by climatic harshness, while mammal biodiversity was related to the increasing availability of resource niches with increasing productivity. Niche packing was more prominent at the regional scale, especially in bioclimatic zones where productivity and vegetation height were less limiting, and in mammal assemblages, suggesting that biodiversity patterns scale differently for birds and mammals.

Paleoindian land use at pluvial Lake Mojave: A temporally and seasonally dynamic wetlands resource patch in California’s central Mojave Desert

This study creates and preliminarily tests a biotic resource structure and optimal foraging theory inspired land use model for Silver Lake, one of two playa lakes that once formed pluvial Lake Mojave in California’s central Mojave Desert. The land use model predicts that when Silver Lake was a high-rank resource patch, Paleoindians optimally decreased inter-basin mobility as part of a wetland stable strategy (WSS); conversely, when Silver Lake was a low-rank resource patch, Paleoindians optimally increased inter-basin mobility using a wetland transient strategy (WTS). Specific land use expectations are developed in 500-year timesteps for the period 14.0–9.0 ka based on yearly and seasonal variations in the productivity of Silver Lake’s wetland habitat. Data limitations with the fine-grained version of the model led us to test a simplified version that supports the hypothesis that Paleoindians selected the optimal land use solution, a WTS, when Silver Lake was a low-rank wetlands resource patch during the terminal Pleistocene/Early Holocene (TP/EH) and more recent groups a WSS when patch rank improved after the Early Holocene. Though the simplified model’s conclusion that Paleoindians employed a WTS during the TP/EH fits the available archaeological evidence at Silver Lake and broader Great Basin/Mojave Desert, it is a static interpretation that implies Paleoindians used a single land use strategy during the several thousand-year TP/EH. This is unrealistic because pluvial lakes were dynamic water bodies that fluctuated through time and directly influenced the extent of and caloric returns from the available wetland habitat. Despite the current inability to test the fine-grained model, which we think would reveal temporal and seasonal variations in Paleoindian land use, not considering or integrating such factors into land use models misses opportunities to better understand the myriad decisions Paleoindians made under ever changing resource structure conditions.

Comparative life cycle assessment of marine microalgae, Nannochloropsis sp. and fishmeal for sustainable protein ingredients in aquaculture feeds

Fishmeal from small marine pelagic fishes reduces their availability for marine wildlife forage and artisanal fishing catches that support food security in lower income coastal nations. Fishmeal is primarily used in feeds for aquaculture, the world’s fastest-growing food sector. Replacing fishmeal in aquafeeds with more environmentally responsible alternative ingredients can help feed aquaculture transition to more sustainable production methods. Protein from defatted marine microalga, Nannochloropsis sp., produced alongside polyunsaturated fatty acids (PUFAs) for the nutraceutical market lacks a comprehensive open-access analysis of environmental impacts of producing these products from biorefineries. This study compared life cycle impacts (global warming potential, water use, land use, marine eutrophication potential, freshwater eutrophication potential, and biotic resource use) of protein from fishmeal produced in a small pelagic fish biorefinery to protein from defatted Nannochloropsis meal. We conducted an attributional life cycle assessment using primary data provided by Cellana LLC to model biomass cultivation and harvesting at the Kona Demonstration Facility (Hawaii, USA) and literature data to model the downstream processing of biomass into a high-protein fishmeal replacement for the aquafeed market and concentrated PUFAs for the nutraceutical market. Material and energy inputs from a Nannochloropsis biorefinery included 2 harvesting scenarios (wet and dry biomass) and 2 scenarios for oil extraction and processing (i.e., oil fractionation and concentration of PUFAs): solvents or supercritical carbon dioxide. Results for aquafeed protein from defatted Nannochloropsis were that cultivation processes had the largest overall effect for all scenarios; urea and pure liquid carbon dioxide were environmental hot spots; and the processing scenario involving dry biomass followed by oil extraction and oil processing with solvent had significantly lower environmental impacts than protein from fishmeal from a small pelagic fish biorefinery for global warming potential, water use, marine eutrophication potential, freshwater eutrophication potential, and biotic resource use, but not for land use. These results suggest that aquafeed from marine microalgae can be an environmentally sustainable replacement for fishmeal if high-value metabolites are coproduced in a biorefinery.

Optimal redesign of a salinity monitoring network in Barataria Basin, Louisiana, USA using discrete entropy theory

We use discrete entropy theory and the MaxT model to optimize a continuous salinity monitoring network in a coastal Louisiana estuary (71 stations, 5 station types). Four station types represent marsh zones based on plant tolerance to salinity: fresh, intermediate, brackish, and saline. The fifth station type include stations in open water spanning the entire estuarine salinity gradient. A dry year (2012) with reduced freshwater inputs, and a wet year (2019) were chosen to test the robustness of the model. Our analysis showed that thirty-one stations formed the core network for both water years, with an additional 12 (2012) and 14 (2019) stations, unique for each year, needed to capture the optimal information for salinity in all five habitats. Fourteen stations could be eliminated with minimal loss of information regardless of whether the estuary was under drought or excess freshwater conditions. The Nash-Sutcliffe coefficient (ENs), coefficient of determination (R2) and the relative error (RE) showed good to excellent agreement between salinity measured by the original network and the modeled salinity of the modified network. Discrete entropy theory and MaxT proved effective in identifying redundancies in information sufficient to allow a 20% reduction of stations. Considering the highly variable nature of salinity within an estuary over short- and long-term temporal scales within a particular geographic location and across the entire estuary, this result was unexpected. Further reductions in stations (and corresponding savings in resources and costs) will require approaches not focused on replicating the exact information content from station to station but rather on measuring those salinity patterns and thresholds that shape biotic resource response in an estuary and possibly a reformulation of monitoring objectives. Monitoring objectives should include sampling for parameters (e.g., suspended sediments and nutrients) that don't require continuous data and are less costly to sustain yet provide equally critical information for understanding coastal wetland habitat sustainability and restoration.

Comparative life cycle assessment of heterotrophic microalgae Schizochytrium and fish oil in sustainable aquaculture feeds

Fish oil is primarily extracted from small marine pelagic fishes, reducing their availability for marine wildlife forage and artisanal fishing catches that support food security in lower income coastal nations. A primary use of fish oil is in feeds for aquaculture, the world’s fastest growing food sector. Efforts to transition fed aquaculture to sustainability includes replacing fish oil in aquafeeds with more environmentally responsible alternative ingredients. The heterotrophic marine microalga Schizochytrium sp., one of the first commercialized alternatives, lacks an open-access, systematic analysis of environmental impacts of substituting fish oil with heterotrophic microalgae from biorefineries. This study compared the “cradle to factory-gate” life cycle impacts of fish oil to whole-cell or extracted oil of Schizochytrium combined with canola oil. We conducted an attributional life cycle assessment using inventory data collected from published literature and patents and received feedback on commercial relevance of model assumptions from industry advisors. We examined sugar from a Brazilian sugarcane biorefinery and sucrose from U.S. sugar beets as feedstocks for heterotrophic cultivation of Schizochytrium; and compared life cycle impacts of extracting Schizochytrium oil using solvent-free microwave extraction to conventional solvent extraction. Results were that: cultivation processes had the largest overall effect for both products in both regions; whole-cell Schizochytrium combined with canola oil had significantly lower environmental impacts, in all assessed categories, than Schizochytrium oil blended with canola oil; and conventional solvent extraction had significantly lower environmental impacts compared to solvent-free microwave extraction except global warming potential. Schizochytrium products, compared to fish oil, had substantially lower biotic resource depletion and, in the case of whole cells combined with canola oil, had significantly lower global warming potential but higher impacts for all other categories, primarily because commercial Schizochytrium production used sugar feedstocks as carbon and energy sources. The mix of lower and higher environmental impacts of Schizochytrium products illustrates the importance of openly identifying environmental trade-offs to inform evidence-based decisions for commercial practices. Environmental impacts should also be weighed against potential human health benefits of maintaining omega-3 fatty acids and avoiding contaminants in fish flesh when considering alternatives to fish oil.

Decomposition analysis of bioresources: Implementing a competitive and sustainable bioeconomy strategy in the Baltic Sea Region

Bioeconomy development has become one of the new trends in policy design and research. This study looks at biotic resource extraction in the Baltic Sea region countries providing detailed country by country analyses of factors affecting changes in resource extraction. The study is based on the index decomposition analysis including factors related to bioeconomy strategies such as the population, share of people employed in bioeconomy, labour intensity, biotic resource extraction productivity, share of bioeconomy, export intensity, and share of bioresource export. The main factors increasing biotic resource extraction were the growth in labour material intensity, biotic extraction productivity and export intensity. However, changes in these factors differed significantly among the countries studied and had different trajectories over time depending on overall performance of the economy. These differences should be taken into account when developing national bioeconomy strategies.

Wood forest resource consumption impact assessment based on a scarcity index accounting for wood functionality and substitutability (WoodSI)

For society to continue to use forest resources in a sustainable manner, we need to be concerned about how they are consumed now and about the future needs. Life cycle assessment (LCA) is a robust tool, scientifically based and possible to be adapted to the quantification of multiple environmental issues in a systemic way. Deforestation and forest degradation continue to take place at threatening rates by the wood resource use and by land use issues (agricultural production, mineral extraction, and human settlement). However, currently, the depletion of forest resources by wood resource use is not adequately considered in LCA. Little progress was done recently in biotic resource depletion impact assessment, and no method can be recommended without considerable restrictions. It is therefore necessary to better characterize the depletion of forest resources in LCA. The present study aims to develop a characterization model that assesses the potential impacts generated by the loss of wood forest resource availability caused by consumption through a functional approach. Considering the operationalization model for biotic resources proposed by Heijungs et al. (1992) and the wood functionality through substitution index proposed by Lima et al. (2018a), a characterization model was developed based on a scarcity index accounting for wood functionality and substitutability (WoodSI). This characterization model considers the consumption, the renewability of the resource, the current stock, and the capacity to substitute the resource (at different wood functions such as sawn wood, wood pulp, wood based panels, wood charcoal, and fire wood) in each country in its calculations. WoodSI is a mid-point model. Three scenarios (less conservative, more conservative, and medium) were analyzed for practitioner choice. Characterization factors were calculated for 193 countries, 60% of which have some level of scarcity and share only 20% of the World forest. The wood functions (or uses) with the highest level of potential World shortage were charcoal and wood pulp production. In general, countries with large forest area or high growth rates do not have any scarcity index detected by the method (e.g., Brazil, Russia, and Australia), but in countries with high consumption rate (such as USA, China) or smaller forests areas, some scarcity was already detected. The WoodSI model contributes to the progress of the natural resource depletion impact category by deepening the discussion in its cause-effect chain and developing an impact model. The wood renewability considers distinct forest classification and its main representative’s species. The instrumentality value is addressed by considering the resource usefulness through its functionality and distribution at country level. It has good data availability since the data obtained are from a public, open database, and values may be updated every 5 years.

The Existence and Uniqueness of the Solution of a Diusive Predator-Prey Model with Omnivory and General Nonlinear Functional Response

In this work, we consider a three species modified Lesie-Gower food web model with general nonlinear functional response and omnivory which is defined as feeding on more than one trophic level. The carrying capacity of the model is proportional to the population size of the biotic resource plus a const. The main objective of this paper is to investigate the existence and uniqueness of the solution of this model. It is shown that the omnivory has important influence on the existence and uniqueness of the solution of the model.

Dynamical behaviors and optimal harvesting of an intraguild prey-predator fishery model with Michaelis-Menten type predator harvesting

The present paper discusses the dynamics and optimal harvesting of an intraguild prey-predator fishery model by incorporating the nonlinear Michaelis-Menten type of harvesting in predator. To our knowledge, there is limited literature working on Michaelis-Menten type of harvesting in a three species intraguild model with variable carrying capacity. The carrying capacity is proportional to the density of biotic resource. The existence of the possible equilibria has been studied along with the stability criteria. We consider the impact of predator fish harvesting as the bifurcation parameter to analyze the long time behavior of the proposed system. From the economic perspective, bionomic equilibrium of the system is studied and optimal harvesting policy is derived with the assistance of Pontryagin Maximum Principle. Finally, numerical results are presented to verify our analytical results. It is shown that in the bifurcation diagrams, the system can exhibit transcritical and Hopf bifurcations in the neighborhood of coexistence equilibrium at low and relatively high level of predator harvesting respectively. Interestingly, the system enters to a bistable region where both the coexistence and predator-free equilibria can be stable depending on the initial values. This bistable behavior might be novel to the existing literature that studied intraguild models with variable carrying capacity. The objective of this study is to derive the optimal threshold for the predator harvesting that gives maximum financial profit while sustaining the fishery resources.

Deep Learning for Prediction of Neoadjuvant Chemoradiotherapy Response in Locally Advanced Rectal Cancer: A Retrospective Multi-Cohort Pathomics Study

Background: Predicting the neoadjuvant chemoradiotherapy (nCRT) response for patient with locally advanced rectal cancer (LARC) would facilitate therapeutic decisions. Yet, the approach to predict the treatment response before nCRT remains challenging. Here, we develop a multicenter deep learning model based on the pretreatment whole slide image (WSI) of hematoxylin and eosin (H&E) stained biopsy to distinguish the pathological complete response (pCR) from the LARC patients. Methods: Consecutive patients with WSI of endoscopic biopsy H&E-stained slides were included from two hospitals as a training cohort (n = 303) and a validation cohort (n = 154), respectively. Tissue regions of each WSI of H&E-stained biopsy slides were automatically segmented and subjected to extract deep features to construct a deep signature by a VGG-16 convolutional neural network model. A prediction model combining the deep signature with clinicopathologic predictors was developed and validated to identify the pCR group. Receiver operating characteristic (ROC) curves and decision curve analysis (DCA) was used to calculate the predictive performance. Findings: The combined model showed good discrimination of the pCR group in two cohorts [the average area under ROC (95% confidence interval): 0.87 (0.83-0.91) in the training cohort, and 0.79 (0.71-0.86) in the independent validation cohort]. Besides, DCA proved that the combined model was clinically valuable. Interpretation: The deep learning model based on biopsy WSI indicates that it might offer a simple preoperative tool to predicts nCRT treatment response for LARC patients. Funding Information: This study was funded by research grants from the National Natural Science Foundation of China [82001986], National Science Fund for Distinguished Young Scholars [81925023], National Key Research and Development Program of China [2017YFC1309102], the Applied Basic Research Projects of Yunnan Province, China [2019FE001-083 and 2018FE001-065], Yunnan digitalization, development and application of biotic resource [202002AA100007]. Declaration of Interests: The authors declare that there are no conflicts of interest. Ethics Approval Statement: The ethics committees of the Sixth Affiliated Hospital of Sun Yat-sen University (SYSU6) and Yunnan Cancer Hospital (YNCH) both approved the multicenter retrospective study. The board waived the requirement for informed consent because of the study’s retrospective nature. All data in the study were de-identified and anonymized.

Comparative environmental impact assessment of aquafeed production: Sustainability implications of forage fish meal and oil free diets

The environmental sustainability of aquaculture food production systems is of critical concern due to its rapid expansion as the fastest growing major food production sector in the world. Among the parameters that contribute to the overall environmental impacts of aquaculture marine-based protein production, aquafeed is identified as an impact hotspot. There is consequently a need to seek more environmentally sustainable aquafeeds to mitigate the adverse environmental impacts associated with aquaculture food production.The environmental and economic sustainability of aquafeeds can be improved using two main approaches: (a) optimizing finite resources use (e.g. fish meal and fish oil), and (b) mitigating waste generation and emissions. A variety of ingredients have been previously proposed, investigated, and utilized to accomplish these strategies, while maintaining acceptable food production efficiencies. However, comprehensive evaluation of the environmental sustainability of aquafeeds with respect to variable ingredients, both in terms of resource use and waste emission has not been conducted.In this work, a holistic life cycle impact assessment of twelve practically formulated and utilized aquafeeds has been performed to provide a comparative evaluation of different aquafeed's environmental impacts, considering resource use (biotic resource use, water intake, and fossil fuel depletion) and emission-based impact categories (ozone depletion, global warming, photochemical smog, acidification, eutrophication, carcinogenics, non-carcinogenics, respiratory effects, and ecotoxicity). Results indicate that the investigated fish meal free diets do not, on the whole, result in a significant decrease in environmental impacts with respect to the use of biotic resources. However, if the substituted ingredients would not propose elevated impacts (e.g. blood meal), these diets can potentially lower the overall environmental impacts of aquafeed production mainly with respect to relevant emission-based indicators (e.g. global warming, eutrophication, ecotoxicity). Findings demonstrate that the investigated fish oil free diets can potentially lower the use of biotic resources. However, to prevent burden shifting, strategies to provide nutrient-rich oils with minimal energy requirement need to be undertaken.

Geometry and evolution of the ecological niche in plant-associated microbes

The ecological niche can be thought of as a volume in multidimensional space, where each dimension describes an abiotic condition or biotic resource required by a species. The shape, size, and evolution of this volume strongly determine interactions among species and influence their current and potential geographical distributions, but the geometry of niches is poorly understood. Here, we analyse temperature response functions and host plant ranges for hundreds of potentially destructive plant-associated fungi and oomycetes. We demonstrate that niche specialization is uncorrelated on abiotic (i.e. temperature response) and biotic (i.e. host range) axes, that host interactions restrict fundamental niche breadth to form the realized niche, and that both abiotic and biotic niches show limited phylogenetic constraint. The ecological terms ‘generalist’ and ‘specialist’ therefore do not apply to these microbes, as specialization evolves independently on different niche axes. This adaptability makes plant pathogens a formidable threat to agriculture and forestry.

Quantifying the primary biotic resource use by fisheries: A global assessment

In this paper, the specific primary production required (SPPR expressed as kg-NPP/kg-fish in wet weight) of more than 1700 marine species were calculated directly from 96 published food web models using the newly developed SPPR calculation framework. The relationship between SPPR and other ecological factors were then statistically analyzed. Among- and within-species variability of SPPR were found to be both explained by trophic level (TL), suggesting similar mechanisms underpinning both sources of variability. Among species, we found that harvesting species at higher mean trophic levels (MTL) increases the mean SPPR by a factor of 19 per 1 unit increase in MTL. Based on our empirical relationship, the mean SPPR of more than 9000 marine species were predicted and subsequently used to assess the primary production required (PPR) to support fisheries in five major fishing countries in Europe. The results indicated that conventional approach to estimating PPR, which neglects food web ecology, can underestimate PPR by up to a factor of 5. Within species, we found that harvesting populations occupying a higher TL leads to a higher SPPR. For example, the SPPR of Atlantic cod in the Celtic Sea (TL = 4.75) was 5 times higher than in the Gilbert Bay (TL = 3.3). Our results, which are based on large amounts of field data, highlight the importance of properly accounting for ecological factors during the impact assessment of fisheries.