Ivan A. Janssens

Ivan A. Janssens
University of Antwerp | UA · Department of Biology

PhD

About

547
Publications
233,493
Reads
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51,273
Citations
Citations since 2017
211 Research Items
30141 Citations
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201720182019202020212022202301,0002,0003,0004,0005,0006,000
201720182019202020212022202301,0002,0003,0004,0005,0006,000
201720182019202020212022202301,0002,0003,0004,0005,0006,000
Additional affiliations
October 2003 - present
University of Antwerp
Position
  • Professor (Full)

Publications

Publications (547)
Article
Full-text available
Warming-induced carbon loss through terrestrial ecosystem respiration ( Re ) is likely getting stronger in high latitudes and cold regions because of the more rapid warming and higher temperature sensitivity of Re ( Q 10 ). However, it is not known whether the spatial relationship between Q 10 and temperature also holds temporally under a future wa...
Article
•Tree stems and soils can act as sources and sinks for greenhouse gases (GHG), i.e. carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Since both uptake and emission capacities can be large, especially in tropical rainforests, accurate assessments of the magnitudes and temporal variations of stem and soil GHG fluxes are required. •We des...
Article
Full-text available
The enhanced vegetation productivity driven by increased concentrations of carbon dioxide (CO2) [i.e., the CO2 fertilization effect (CFE)] sustains an important negative feedback on climate warming, but the temporal dynamics of CFE remain unclear. Using multiple long-term satellite- and ground-based datasets, we showed that global CFE has declined...
Article
Full-text available
Tropical forests are generally considered to stand upon nutrient-poor soils, but soil nutrient concentrations and availabilities can vary greatly at local scale due to topographic effects on erosion and water drainage. In this study we physically and chemically characterised the soils of 12 study plots situated along a catena with a shallow slope i...
Article
Full-text available
Global change is affecting terrestrial carbon balances. The effect of climate on ecosystem carbon balance has been largely explored, but the roles of other concurrently changing factors, such as diversity and nutrient availability, remain elusive. We used eddy-covariance carbon-flux measurements from 62 ecosystems from which we compiled information...
Article
Over the past decades, global warming has led to a lengthening of the time window during which temperatures remain favorable for carbon assimilation and tree growth, resulting in a lengthening of the green season. The extent to which forest green seasons have tracked the lengthening of this favorable period under climate warming, however, has not b...
Article
Understanding how and why soil microbial communities respond to temperature changes is important for understanding the drivers of microbial distribution and abundance. Studying soil microbe responses to warming is often made difficult by concurrent warming effects on soil and vegetation and by a limited number of warming levels preventing the detec...
Article
Full-text available
Soil microbes ultimately drive the mineralization of soil organic carbon and thus ecosystem functions. We compiled a dataset of the seasonality of microbial biomass carbon (MBC) and developed a semi-mechanistic model to map monthly MBC across the globe. MBC exhibits an equatorially symmetric seasonality between the Northern and Southern Hemispheres...
Article
Full-text available
A shift in management to improve the ecological function of mature plantations of exotic species can have important effects on the ecosystem climate mitigation potential. This study investigated the effect of two common forest management strategies for Scots pine (Pinus sylvestris L.) stands on the C storage after 15 years of management. Two pairs...
Article
Full-text available
Climatic warming has lengthened the photosynthetically active season in recent decades, thus affecting the functioning and biogeochemistry of ecosystems, the global carbon cycle and climate. Temperature response of carbon uptake phenology varies spatially and temporally, even within species, and daily total intensity of radiation may play a role. W...
Article
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The potential of mitigation actions to limit global warming within 2 °C (ref. ¹) might rely on the abundant supply of biomass for large-scale bioenergy with carbon capture and storage (BECCS) that is assumed to scale up markedly in the future2–5. However, the detrimental effects of climate change on crop yields may reduce the capacity of BECCS and...
Article
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Carbon dioxide removal (CDR) that increases the area of forest cover or bio-energy crops inherently competes for land with crop and livestock systems, compromising food security, or will encroach natural lands, compromising biodiversity. Mass deployment of these terrestrial CDR technologies to reverse climate change therefore cannot be achieved wit...
Article
Full-text available
Tropical forests take up more carbon (C) from the atmosphere per annum by photosynthesis than any other type of vegetation. Phosphorus (P) limitations to C uptake are paramount for tropical and subtropical forests around the globe. Yet the generality of photosynthesis-P relationships underlying these limitations are in question, and hence are not r...
Article
Full-text available
Vegetation indices (VIs) derived from optical sensors have been used as proxies for monitoring gross primary productivity (GPP). In contrast to satellite-based VIs, whose temporal resolution is typically limited, especially in cloudy areas, in situ derived VIs may have a higher temporal resolution. This fine temporal frequency implies much larger s...
Article
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Secondary forests constitute an increasingly important component of tropical forests worldwide. Although cycling of essential nutrients affects recovery trajectories of secondary forests, the effect of nutrient limitation on forest regrowth is poorly constrained. Here we use three lines of evidence from secondary forest succession sequences in cent...
Article
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Quantifying and analyzing leaching water is essential to understand water and nutrient cycles and the vertical transport of elements through soils. Zero Tension Lysimeters (ZTLs) have been widely used to capture the soil solution leaching by gravity. This study designed and evaluated a 3D‐printed ZTL (ZTL3D) with specific characteristics and materi...
Article
Full-text available
Global warming may lead to carbon transfers from soils to the atmosphere, yet this positive feedback to the climate system remains highly uncertain, especially in subsoils (Ilyina and Friedlingstein, 2016; Shi et al., 2018). Using natural geothermal soil warming gradients of up to +6.4 ∘C in subarctic grasslands (Sigurdsson et al., 2016), we show t...
Article
Sun-induced chlorophyll fluorescence (SIF) is one of the most promising remote-sensing signals to assess spatio-temporal variation in photosynthesis. Yet, it has been shown that the positive linear relationship of SIF and photosynthesis, often reported from satellite and proximal remote sensing, is mainly driven by the amount of absorbed photosynth...
Article
Full-text available
The production of anthropogenic reactive nitrogen (N) has grown so much in the last century that quantifying the effect of N enrichment on plant growth has become a central question for carbon (C) cycle research. Numerous field experiments generally found that N enrichment increased site-scale plant biomass, although the magnitude of the response a...
Conference Paper
Full-text available
To capture the vegetation-driven seasonal variability in surface fluxes, land surface models (LSM) simulate the evolution of leaf area index (LAI) prognostically. A common approach to achieve this, is by directly coupling the carbon assimilation flux to the leaf biomass evolution. In this study, we evaluate this scheme by isolating it from the LSM...
Article
Full-text available
Phosphorus (P) is an essential macronutrient for plant growth and one of the least available nutrients in soil. P limitation is often a major constraint for plant growth globally. Although P addition experiments have been carried out to study the long-term effects on yield, data on P addition effects on seasonal variation in leaf-level photosynthes...
Preprint
Full-text available
Understanding how and why soil microbial communities respond to temperature changes is important for understanding the drivers of microbial distribution and abundance. A unique area in Iceland, where soil temperatures have increased due to geothermic activity four years prior to sampling, creating a stable gradient of ambient to +40°C, allowed us t...
Article
Full-text available
How soil microorganisms respond to global warming is key to infer future soil-climate feedbacks, yet poorly understood. Here, we applied metatranscriptomics to investigate microbial physiological responses to medium-term (8 years) and long-term (>50 years) subarctic grassland soil warming of +6°C. Besides indications for a community-wide up-regulat...
Article
Priming is the change of microbial soil organic matter (SOM) decomposition induced by a labile carbon (C) source. It is recognised as an important mechanism influencing soil C dynamics and C storage in terrestrial ecosystems. Microbial nitrogen (N) mining in SOM and preferential substrate utilisation, i.e., a shift in microbial carbon use from SOM...
Article
Rock‐derived nutrients such as calcium (Ca), magnesium (Mg), phosphorus (P), and potassium (K) are essential plant resources, yet depleted in highly weathered tropical soils, leading to nutrient limitation of productivity or other ecosystem processes. Despite this, substantial amounts of rock‐derived nutrients occur within wood, which raises questi...
Article
Full-text available
Subterranean ecosystems play an active role in the global carbon cycle, yet only a few studies using indirect methods have focused on the role of the cave microbiota in this critical cycle. Here we present pioneering research based on in situ real-time monitoring of CO2 and CH4 diffusive fluxes and concurrent δ¹³C geochemical tracing in caves, comb...
Article
Long-term soil warming and nitrogen (N) availability have been shown to affect microbial biomass and community composition. Altered assimilation patterns of recent plant-derived C and changes in soil C stocks following warming as well as increased N availability are critical in mediating the direction and magnitude of these community shifts. A ¹³C...
Article
Climate warming has substantially advanced the timing of spring leaf-out of woody species at middle and high latitudes, albeit with large differences. Insights in the spatial variation of this climate warming response may therefore help to constrain future trends in leaf-out and its impact on energy, water and carbon balances at global scales. In t...
Article
Aim: The aims of this study were to evaluate the changes in the length of time period between leaf-out and flowering across temperate tree species, and associate these changes with potential physiological and environmental drivers to enhance mechanistic insight in these phenomena. Location: Central Europe Time period: 1980-2016 Major taxa studie...
Preprint
Full-text available
Global warming may lead to carbon transfers from soils to the atmosphere, yet this positive feedback to the cli- mate system remains highly uncertain, especially in subsoils (Ilyina and Friedlingstein, 2016; Shi et al., 2018). Using natural geothermal soil warming gradients of up to +6.4 °C in subarctic grasslands (Sigurdsson et al., 2016), we show...
Article
Full-text available
Terrestrial biosphere models typically use the biochemical model of Farquhar, von Caemmerer, and Berry (1980) to simulate photosynthesis, which requires accurate values of photosynthetic capacity of different biomes. However, data on tropical forests are sparse and highly variable due to the high species diversity, and it is still highly uncertain...
Article
Full-text available
As the COVID‐19 virus spread over the world, governments restricted mobility to slow transmission. Public health measures had different intensities across European countries but all had significant impact on people's daily lives and economic activities, causing a drop of CO2 emissions of about 10% for the whole year 2020. Here, we analyze changes i...
Article
Full-text available
Understanding the critical soil moisture (SM) threshold (θcrit) of plant water stress and land surface energy partitioning is a basis to evaluate drought impacts and improve models for predicting future ecosystem condition and climate. Quantifying the θcrit across biomes and climates is challenging because observations of surface energy fluxes and...
Article
Full-text available
Global warming increases soil temperatures and promotes faster growth and turnover of soil microbial communities. As microbial cell walls contain a high proportion of organic nitrogen, a higher turnover rate of microbes should also be reflected in an accelerated organic nitrogen cycling in soil. We used a metatranscriptomics and metagenomics approa...
Article
Full-text available
Understanding the mechanisms that drive the change of biotic assemblages over space and time is the main quest of community ecology. Assessing the relative importance of dispersal and environmental species selection in a range of organismic sizes and motilities has been a fruitful strategy. A consensus for whether spatial and environmental distance...
Article
A number of negative emission technologies (NETs) have been proposed to actively remove CO 2 from the atmosphere, with enhanced silicate weathering (ESW) as a relatively new NET with considerable climate change mitigation potential. Models calibrated to ESW rates in lab experiments estimate the global potential for inorganic carbon sequestration by...
Article
Full-text available
The leaf economics spectrum1,2 and the global spectrum of plant forms and functions³ revealed fundamental axes of variation in plant traits, which represent different ecological strategies that are shaped by the evolutionary development of plant species². Ecosystem functions depend on environmental conditions and the traits of species that comprise...
Article
Full-text available
Tropical forests are biodiversity hotspots, but it is not well understood how this diversity is structured and maintained. One hypothesis rests on the generation of a range of metabolic niches, with varied composition, supporting a high species diversity. Characterizing soil metabolomes can reveal fine-scale differences in composition and potential...
Article
Full-text available
Since 1750, land use change and fossil fuel combustion has led to a 46 % increase in the atmospheric carbon dioxide (CO 2 ) concentrations, causing global warming with substantial societal consequences. The Paris Agreement aims to limiting global temperature increases to well below 2°C above pre-industrial levels. Increasing levels of CO 2 and othe...
Article
Consistent information on the current elemental composition of vegetation at global scale and the variables that determine it is lacking. To fill this gap, we gathered a total of 30912 georeferenced records on woody plants foliar concentrations of N, P, and K from published databases, and produced global maps of foliar N, P and K concentrations fo...
Article
Full-text available
Our study suggests that the global CO2 fertilization effect (CFE) on vegetation photosynthesis has declined during the past four decades. The Comments suggest that the temporal inconsistency in AVHRR data and the attribution method undermine the results’ robustness. Here, we provide additional evidence that these arguments did not affect our findin...
Article
Full-text available
High-throughput field phenotyping using close remote sensing platforms and sensors for non-destructive assessment of plant traits can support the objective evaluation of yield predictions of large breeding trials. The main objective of this study was to examine the potential of unmanned aerial vehicle (UAV)-based structural and spectral features an...
Article
Full-text available
The functional adaptive responses of higher plants to biotic interactions with herbivores and fungi have long been topics of research. One constraint to obtaining a comprehensive understanding of the most general plant responses, however, has been the difficulty of studying all plant functional shifts simultaneously due to analytical limitations. N...
Article
Full-text available
Significance There is a lack of global observational data to monitor the application of nonpharmaceutical interventions (NPI) and evaluate the effect of NPIs for pandemic management in different territories. We find that economic activity reduction inferred from NO 2 is a driver of case deceleration in most of the territories. The effect, however,...
Preprint
Full-text available
Terrestrial biosphere models typically use the biochemical model of Farquhar, von Caemmerer and Berry (1980) to simulate photosynthesis, which requires accurate values of photosynthetic capacity of different biomes. However, data on tropical forests are sparse and highly variable due to the high species diversity, and it is still highly uncertain h...
Article
Soil phosphatase enzymes are produced by plant roots and microorganisms and play a key role in the cycling of phosphorus (P), an often‐limiting element in terrestrial ecosystems. The production of these enzymes in soil is the most important biological strategy for acquiring phosphate ions from organic molecules. Previous works showed how soil poten...
Article
Production, emission, and absorption of biogenic volatile organic compounds (BVOCs) in ecosystem soils and associated impacts of nutrient availability are unclear; thus, predictions of effects of global change on source-sink dynamic under increased atmospheric N deposition and nutrition imbalances are limited. Here, we report the dynamics of soil B...
Conference Paper
Full-text available
Surface carbon fluxes associated with terrestrial vegetation play a key role in the global carbon cycle. Remote sensing (RS) and land surface models (LSM) have demonstrated to be valuable tools in assessing the gross primary production (GPP). Yet, the seasonal variability of this flux, and timing of the seasonal cycle remain challenging to observe...
Preprint
Full-text available
Despite being an essential macronutrient for plant growth, phosphorus (P) is one of the least available nutrients in soils and P limitation is often a major constraint for plant growth globally. Although P addition experiments have been carried out to study the long-term effects on the yield, data on P addition effects to seasonal variation in leaf...
Article
Full-text available
Ecological stoichiometry and studies of biogeochemical niches have mainly focused on plankton and vascular plants, but the phenotypically closest modern relatives of early plants, bryophytes, have been largely neglected. We analysed C:N:P stoichiometries and elemental compositions (K, Na, Mg, Ca, S, Fe) of 35 widely distributed bryophyte species in...
Article
Industrial phosphorus (P) fertilizer has substantially improved global food production, but has also led to environmental impacts. Intensive global agricultural trade has increased and the impacts of trade on aggravating or alleviating future P scarcity must be examined, especially for the most vulnerable countries. We combined data to estimate the...
Article
The effect of warming is stronger in arctic and sub-arctic latitudes than in temperate and tropical zones. We studied soil metabolomes along two soil-warming gradients (0 to +15 °C). One temperature gradient has been present for at least 50 years and possibly even centuries (long-term treatment), while the second gradient was created after a shallo...
Article
Full-text available
Branched glycerol dialkyl glycerol tetraethers (BrGDGTs) are a suite of orphan bacterial membrane lipids commonly used as paleo-environmental proxies for mean annual air temperature (MAT) and pH. Recent calibrations between the Methylation of Branched Tetraethers index (MBT’5ME) and MAT, based on modern surface soils (including peats), show a consi...
Article
Full-text available
In tropical forests, free-living Biological nitrogen (N) fixation (BNF) in soil and litter tends to decrease when substrate N concentrations increase, whereas increasing phosphorus (P) and molybdenum (Mo) soil and litter concentrations have been shown to stimulate free-living BNF rates. Yet, very few studies explored the effects of adding N, P, and...
Article
Negative emission technologies underpin socioeconomic scenarios consistent with the Paris Agreement. Afforestation and bioenergy coupled with carbon dioxide (CO2) capture and storage are the main land negative emission technologies proposed, but the range of nature-based solutions is wider. Here we explore soil amendment with powdered basalt in nat...
Article
Full-text available
Resorption is the active withdrawal of nutrients before leaf abscission. This mechanism represents an important strategy to maintain efficient nutrient cycling; however, resorption is poorly characterized in old-growth tropical forests growing in nutrient-poor soils. We investigated nutrient resorption from leaves in 39 tree species in two tropical...
Article
Full-text available
1. Nutrient economy and plant nutrient concentrations have been suggested as im- portant selective pressures of reproductive traits in vascular plants. However, evidence supporting that the reproduction of bryophytes and their reproductive traits have also been conditioned by nutrient availability is lacking. 2. We here analysed the nutrient (N, P,...
Article
Full-text available
As China ramped-up coal power capacities rapidly while CO 2 emissions need to decline, these capacities would turn into stranded assets. To deal with this risk, a promising option is to retrofit these capacities to co-fire with biomass and eventually upgrade to CCS operation (BECCS), but the feasibility is debated with respect to negative impacts o...
Preprint
Full-text available
As the COVID-19 virus spread over the world, governments restricted mobility to slow transmission. Public health measures had different intensities across European countries but all had significant impact on peoples daily lives and economic activities, causing a drop of CO2 emissions of about 10% for the whole year 2020. Here, we analyze changes in...
Article
Studies on ecological stoichiometry (ES) have increased rapidly in number in recent years. Continuous exploration of classical concepts such as the growth-rate hypothesis (GRH), ), which is based on the relationship between the nitrogen:phosphorus (N:P) ratio of organisms and their growth-rate capacity, has identified new patterns and uncertainties...
Article
Full-text available
The global socio-economic and agricultural expansion is accompanied by large inputs of nitrogen (N) and phosphorus (P) on land and by a serious alteration of the water cycle and water quality. The Mediterranean basin represents a paradigmatic region to study the entangled nutrient and water challenges because the region, where many of the world's c...