Biogeochemistry

Article	Citations
Freshwater salinization syndrome: from emerging global problem to managing risks	69
Biological nitrogen fixation by alternative nitrogenases in terrestrial ecosystems: a review	68
How humans alter dissolved organic matter composition in freshwater: relevance for the Earth’s biogeochemistry	61
A holistic framework integrating plant-microbe-mineral regulation of soil bioavailable nitrogen	46
Phosphorus and carbon in soil particle size fractions: A synthesis	44
From hogs to HABs: impacts of industrial farming in the US on nitrogen and phosphorus and greenhouse gas pollution	39
Cellular and extracellular C contributions to respiration after wetting dry soil	37
Atmospheric deposition of elements and its relevance for nutrient budgets of tropical forests	32
The role of clay content and mineral surface area for soil organic carbon storage in an arable toposequence	32
Quantifying microbial control of soil organic matter dynamics at macrosystem scales	31
Evidence linking calcium to increased organo-mineral association in soils	29
Recent increases of rainfall and flooding from tropical cyclones (TCs) in North Carolina (USA): implications for organic matter and nutrient cycling in coastal watersheds	29
Assessing microbial residues in soil as a potential carbon sink and moderator of carbon use efficiency	28
Unified concepts for understanding and modelling turnover of dissolved organic matter from freshwaters to the ocean: the UniDOM model	28
Soil organic carbon fractions in the Great Plains of the United States: an application of mid-infrared spectroscopy	28
Anhydrosugars as tracers in the Earth system	28
Volcanic CO2 seep geochemistry and use in understanding ocean acidification	26
Role of external inputs of nutrients to aquatic ecosystems in determining prevalence of nitrogen vs. phosphorus limitation of net primary productivity	25
Tree stem methane emissions from subtropical lowland forest (Melaleuca quinquenervia) regulated by local and seasonal hydrology	25
Influence of electron acceptor availability and microbial community structure on sedimentary methane oxidation in a boreal estuary	25
Landscape controls on riverine export of dissolved organic carbon from Great Britain	25
Bioavailable DOC: reactive nutrient ratios control heterotrophic nutrient assimilation—An experimental proof of the macronutrient-access hypothesis	24
Using radon to quantify groundwater discharge and methane fluxes to a shallow, tundra lake on the Yukon-Kuskokwim Delta, Alaska	24
Dissolved methane concentrations and fluxes to the atmosphere from a tropical floodplain lake	24
Interactions between labile carbon, temperature and land use regulate carbon dioxide and methane production in tropical peat	23

The linkage of 13C and 15N soil depth gradients with C:N and O:C stoichiometry reveals tree species effects on organic matter turnover in soil	23
Differential effects of wetting and drying on soil CO2 concentration and flux in near-surface vs. deep soil layers	22
Groundwater nitrification and denitrification are not always strictly aerobic and anaerobic processes, respectively: an assessment of dual-nitrate isotopic and chemical evidence in a stratified alluvi	22
Rock weathering controls the potential for soil carbon storage at a continental scale	22
Measuring nitrogen fixation by the acetylene reduction assay (ARA): is 3 the magic ratio?	21
Experimental shifts of hydrologic residence time in a sandy urban stream sediment–water interface alter nitrate removal and nitrous oxide fluxes	21
The role of the understory in litter DOC and nutrient leaching in boreal forests	20
The effects of temperature on soil phosphorus availability and phosphatase enzyme activities: a cross-ecosystem study from the tropics to the Arctic	19
Stabilisation of soil organic matter: interactions between clay and microbes	18
Biogeochemical constraints on climate change mitigation through regenerative farming	18
Fertilizer, landscape features and climate regulate phosphorus retention and river export in diverse Midwestern watersheds	18
Leaf litter inputs reinforce islands of nitrogen fertility in a lowland tropical forest	18
Large nitrogen oxide emission pulses from desert soils and associated microbiomes	18
Patterns and predictors of soil organic carbon storage across a continental-scale network	18
Divergent controls on carbon concentration and persistence between forests and grasslands of the conterminous US	18
Constraining dissolved organic matter sources and temporal variability in a model sub-Arctic lake	18
How much carbon can be added to soil by sorption?	18
Stable isotopes as an effective tool for N nutrient source identification in a heavily urbanized and agriculturally intensive tropical lowland basin	17
Variations in the nitrogen saturation threshold of soil respiration in grassland ecosystems	17
Dissolved black carbon in throughfall and stemflow in a fire-managed longleaf pine woodland	17
Some thoughts on the biogeochemical cycling of potassium in terrestrial ecosystems	16
Does soil organic carbon quality or quantity govern relative temperature sensitivity in soil aggregates?	16
How will a drier climate change carbon sequestration in soils of the deciduous forests of Central Europe?	16
Mycorrhizal type effects on leaf litter decomposition depend on litter quality and environmental context	15
Geochemical focusing and sequestration of manganese during eutrophication of Lake Stechlin (NE Germany)	15
Soil C, N and P cycling enzyme responses to nutrient limitation under elevated CO2	15
Benthic fluxes of dissolved oxygen and nutrients across hydrogeomorphic zones in a coastal deltaic floodplain within the Mississippi River delta plain	15
Influence of the physico-chemical properties of root mucilage and model substances on the microstructural stability of sand	15
Seasonal variability of sediment controls of nitrogen cycling in an agricultural stream	15
The fate of calcium in temperate forest soils: a Ca K-edge XANES study	14
Mineral stabilization of soil carbon is suppressed by live roots, outweighing influences from litter quality or quantity	14
Biogeochemical cycling of phosphorus in subsoils of temperate forest ecosystems	14
Altered litter inputs modify carbon and nitrogen storage in soil organic matter in a lowland tropical forest	14
Integrating atmospheric deposition-driven nutrients (N and P), microbial and biogeochemical processes in the watershed with carbon and nutrient export to the Ganga River	14
Effectiveness of phosphorus control under extreme heatwaves: implications for sediment nutrient releases and greenhouse gas emissions	14
Fate and stability of dissolved organic carbon in topsoils and subsoils under beech forests	14
Origin and fate of dissolved organic matter in four shallow Baltic Sea estuaries	14
Dimethylated sulfur production in batch cultures of Southern Ocean phytoplankton	13
Effects of elevated temperature on microbial breakdown of seagrass leaf and tea litter biomass	13
Differential effects of redox conditions on the decomposition of litter and soil organic matter	13
The evolution of biogeochemistry: revisited	13
Elevated nutrient inputs to marshes differentially impact carbon and nitrogen cycling in two northern Gulf of Mexico saltmarsh plants	13
Nitrate reduction pathways and interactions with iron in the drainage water infiltration zone of a riparian wetland soil	13
Divergent controls of soil organic carbon between observations and process-based models	13
Runoff-driven export of terrigenous particulate organic matter from a small mountainous river: sources, fluxes and comparisons among different rivers	13
Rapid nitrate reduction produces pulsed NO and N2O emissions following wetting of dryland soils	13
A spectral weighting function for abiotic photodegradation based on photochemical emission of CO2 from leaf litter in sunlight	13
Modeling indirect N2O emissions along the N cascade from cropland soils to rivers	12
Biogeochemical evolution of soil organic matter composition after a decade of warming and nitrogen addition	12
The role of woody detritus in biogeochemical cycles: past, present, and future	12

Seasonally distinct sources of N2O in acid organic soil drained for agriculture as revealed by N2O isotopomer analysis	12
Contrasting temperature responses of soil respiration derived from soil organic matter and added plant litter	12
Anthropogenic landcover impacts fluvial dissolved organic matter composition in the Upper Mississippi River Basin	12
Quantifying the frequency of synchronous carbon and nitrogen export to the river network	11
Linear two-pool models are insufficient to infer soil organic matter decomposition temperature sensitivity from incubations	11
Controls on soil microbial carbon use efficiency over long-term ecosystem development	11
Natural atmospheric deposition of molybdenum: a global model and implications for tropical forests	11
Storm size and hydrologic modification influence nitrate mobilization and transport in agricultural watersheds	11
Dominant tree mycorrhizal associations affect soil nitrogen transformation rates by mediating microbial abundances in a temperate forest	11
Signatures of an abiotic decomposition pathway in temperate forest leaf litter	11
Mulching with pruned fronds promotes the internal soil N cycling and soil fertility in a large-scale oil palm plantation	11
Effect of drainage on microbial enzyme activities and communities dependent on depth in peatland soil	11
Beyond total carbon: conversion of amazon forest to pasture alters indicators of soil C cycling	11
Desiccation time and rainfall control gaseous carbon fluxes in an intermittent stream	11
Soil organic matter turnover rates increase to match increased inputs in grazed grasslands	11
Soil microorganisms regulate extracellular enzyme production to maximize their growth rate	11
Daily denitrification rates in floodplains under contrasting pedo-climatic and anthropogenic contexts: modelling at the watershed scale	11
Environmental control on carbon exchange of natural and planted forests in Western Himalayan foothills of India	11
Influences of the landscape pattern on riverine nitrogen exports derived from legacy sources in subtropical agricultural catchments	11
From burned slopes to streams: how wildfire affects nitrogen cycling and retention in forests and fire-prone watersheds	10
Dissolved organic carbon production and flux under long-term litter manipulations in a Pacific Northwest old-growth forest	10
Availability of soil base cations and micronutrients along soil profile after 13-year nitrogen and water addition in a semi-arid grassland	10
A ten year record of nitrate retention and solute trends in a Wisconsin sand plains stream: temporal variation at multiple scales	10
Spruce forest afforestation leading to increased Fe mobilization from soils	10
The evolution of stream dissolved organic matter composition following glacier retreat in coastal watersheds of southeast Alaska	10
The partitioning of litter carbon fates during decomposition under different rainfall patterns: a laboratory study	9
Artificial ponds as hotspots of nitrogen removal in agricultural watershed	9
Persistent anthropogenic legacies structure depth dependence of regenerating rooting systems and their functions	9
Dissolved organic matter in large lakes: a key but understudied component of the carbon cycle	9
Eutrophication overcoming carbonate precipitation in a tropical hypersaline coastal lagoon acting as a CO2 sink (Araruama Lagoon, SE Brazil)	9
Functional identity and functional diversity co-regulate litter mixture decomposition and nitrogen release in boreal riparian forest ponds	9
The influence of tillage and fertilizer on the flux and source of nitrous oxide with reference to atmospheric variation using laser spectroscopy	9
Four years of litter input manipulation changes soil microbial characteristics in a temperate mixed forest	9
Soil carbon sequestration as a climate strategy: what do farmers think?	9
Soil age and soil organic carbon content shape biochemical responses to multiple freeze–thaw events in soils along a postmining agricultural chronosequence	9
Long-term litter type treatments alter soil carbon composition but not microbial carbon utilization in a mixed pine-oak forest	9
Accumulation of germanium (Ge) in plant tissues of grasses is not solely driven by its incorporation in phytoliths	8
Soil nitrogen cycle unresponsive to decadal long climate change in a Tasmanian grassland	8
Trade-off between ‘new’ SOC stabilisation from above-ground inputs and priming of native C as determined by soil type and residue placement	8
Mercury and selenium loading in mountaintop mining impacted alkaline streams and riparian food webs	8
Soil greenhouse gas fluxes following conventional selective and reduced-impact logging in a Congo Basin rainforest	8
Phosphorus, nitrogen and dissolved organic carbon fluxes from sediments in freshwater rivermouths entering Green Bay (Lake Michigan; USA)	8
Assessing thermal acclimation of soil microbial respiration using macromolecular rate theory	8
Grassland management regimes regulate soil phosphorus fractions and conversion between phosphorus pools in semiarid steppe ecosystems	8
Contrasting stream nitrate and sulfate response to recovery from experimental watershed acidification	8
Nitrogen transport in a tundra landscape: the effects of early and late growing season lateral N inputs on arctic soil and plant N pools and N2O fluxes	8
Development of energetic and enzymatic limitations on microbial carbon cycling in soils	8
Microbial functions and soil nitrogen mineralisation processes in the soil of a cool temperate forest in northern Japan	8
A “toy” model of biogeochemical dynamics on climate gradients	8
Rapid depletion of dissolved organic sulphur (DOS) in freshwaters	8
Evidence for phosphorus limitation in high-elevation unvegetated soils, Niwot Ridge, Colorado	8
A “toy model” analysis of causes of nitrogen limitation in terrestrial ecosystems	8
Dissolved organic nutrients at the interface of fresh and marine waters: flow regime changes, biogeochemical cascades and picocyanobacterial blooms—the example of Florida Bay, USA	8
Mechanisms influencing physically sequestered soil carbon in temperate restored grasslands in South Africa and North America	8
Microsites and early litter decomposition patterns in the soil and forest canopy at regional scale	7
The biotic contribution to the benthic stream sediment phosphorus buffer	7
Shifts in microbial stoichiometry upon nutrient addition do not capture growth-limiting nutrients for soil microorganisms in two subtropical soils	7
Variation of soil carbon accumulation across a topographic gradient in a humid subtropical mountain forest	7
Bacterial communities and nitrogen transformation genes in streambank legacy sediments and implications for biogeochemical processing	7
Supplemental precipitation accelerates decay but only in photodegraded litter and implications that sunlight promotes leaching loss	7
Determining ecosystem functioning in Brazilian biomes through foliar carbon and nitrogen concentrations and stable isotope ratios	7
Impacts of litter decay on organic leachate composition and reactivity	7
Si cycling in transition zones: a study of Si isotopes and biogenic silica accumulation in the Chesapeake Bay through the Holocene	7
Exchanges of major elements in a deciduous forest canopy	7
Active methane processing microbes and the disproportionate role of NC10 phylum in methane mitigation in Amazonian floodplains	7
Pulse labelling of deep soil layers in forest with 13CH4: testing a new method for tracing methane in the upper horizons, understorey vegetation and tree stems using laser-based spectrometry	7
Integrated isotope and microbiome analysis indicates dominance of denitrification in N2O production after rewetting of drained fen peat	7
Carbon storage and burial in thermokarst lakes of permafrost peatlands	7
Low CO2 evasion rate from the mangrove-surrounding waters of the Sundarbans	7
C:N:P stoichiometry and nutrient limitation of stream biofilms impacted by grassland degradation on the Qinghai-Tibet Plateau	7
Twenty years of litter manipulation reveals that above-ground litter quantity and quality controls soil organic matter molecular composition	7
δ2Hn-alkane and δ18Osugar biomarker proxies from leaves and topsoils of the Bale Mountains, Ethiopia, and implications for paleoclimate reconstructions	7
The long-term fate of deposited nitrogen in temperate forest soils	7
Dissolved organic matter composition and reactivity in Lake Victoria, the world’s largest tropical lake	7
Carbon budgets for soil and plants respond to long-term warming in an Alaskan boreal forest	7
Ecological stoichiometry as a foundation for omics-enabled biogeochemical models of soil organic matter decomposition	7
Measuring the influence of environmental conditions on dissolved organic matter biodegradability and optical properties: a combined field and laboratory study	7
Background nitrogen deposition controls the effects of experimental nitrogen addition on soil gross N transformations in forest ecosystems	7
Leaf stoichiometry is synergistically-driven by climate, site, soil characteristics and phylogeny in karst areas, Southwest China	7
Molecular dynamics of foliar litter and dissolved organic matter during the decomposition process	6

Nitrogen biogeochemistry of water-agro-food systems: the example of the Seine land-to-sea continuum	6
Ice cover and thaw events influence nitrogen partitioning and concentration in two shallow eutrophic lakes	6
Soil phosphorus status and P nutrition strategies of European beech forests on carbonate compared to silicate parent material	6
Nitrous oxide emissions in proportion to nitrification in moist temperate forests	6
Limited effect of drainage on peat properties, porewater chemistry, and peat decomposition proxies in a boreal peatland	6
Vegetation and hydrology stratification as proxies to estimate methane emission from tidal marshes	6
Saltwater intrusion in context: soil factors regulate impacts of salinity on soil carbon cycling	6
Landscape controls on total mercury and methylmercury export from small boreal forest catchments	6
Nitrogen wet deposition stoichiometry: the role of organic nitrogen, seasonality, and snow	6
Immobilization of agricultural phosphorus in temperate floodplain soils of Illinois, USA	6
Drivers of greenhouse gas emissions from standing dead trees in ghost forests	6
Living particulate fluxes in throughfall and stemflow during a pollen event	6
Roots regulate microbial N processes to achieve an efficient NH4+ supply in the rhizosphere of alpine coniferous forests	6
Further investigations into the use of tree rings as archives of atmospheric mercury concentrations	6
Mycorrhizal type determines root–microbial responses to nitrogen fertilization and recovery	6
C:N:P stoichiometry in six distinct habitats of a glacier terminus in the source area of the Yangtze River	6
Hydrodynamic impacts on tidal-scale dissolved inorganic nitrogen cycling and export across the estuarine turbidity maxima to coast	6
Bark decomposition in white oak soil outperforms eastern hemlock soil, while bark type leads to consistent changes in soil microbial composition	6
Wastewater-boosted biodegradation amplifying seasonal variations of pCO2 in the Mekong–Tonle Sap river system	6
Isotopic signals in an agricultural watershed suggest denitrification is locally intensive in riparian areas but extensive in upland soils	6
Pelagic denitrification and methane oxidation in oxygen-depleted waters of the Louisiana shelf	6
Influence of earthworms on apolar lipid features in soils after 1 year of incubation	6
Growing season soil warming may counteract trend of nitrogen oligotrophication in a northern hardwood forest	6
CH4 uptake along a successional gradient in temperate alpine soils	6
Windsock behavior: climatic control on iron biogeochemistry in tropical mangroves	6
Characterizing bioavailable phosphorus concentrations in an agricultural stream during hydrologic and streambed disturbances	6
Isotope alteration caused by changes in biochemical composition of sedimentary organic matter	5
Evidence from molecular marker and FT-ICR-MS analyses for the source and transport of dissolved black carbon under variable water discharge of a subtropical Estuary	5
Seasonality is more important than forest type in regulating the pool size and composition of soil soluble N in temperate forests	5
Nitrogen cycling in tropical dry forests is sensitive to changes in rainfall regime and nitrogen deposition	5
Radiocarbon analysis reveals that vegetation facilitates the release of old methane in a temperate raised bog	5
High initial soil organic matter level combined with aboveground plant residues increased microbial carbon use efficiency but accelerated soil priming effect	5
Aggregate formation and organo-mineral association affect characteristics of soil organic matter across soil horizons and parent materials in temperate broadleaf forest	5
Decoupling of silica, nitrogen and phosphorus cycling in a meromictic subalpine lake (Lake Iseo, Italy)	5
Catchment water quality in the year preceding and immediately following restoration of a drained afforested blanket bog	5
Manganese limitations and the enhanced soil carbon sequestration of temperate rainforests	5
Kiss the ground (and make a wish): soil science and hollywood	5
Post-depositional alteration of stable isotope signals by preferential degradation of algae-derived organic matter in reservoir sediments	5
Patterns and drivers of multi-annual CO2 emissions within a temperate suburban neighborhood	5
Vulnerability of soil organic matter to microbial decomposition as a consequence of burning	5
Potential for soil legacy phosphorus release from restored riparian wetlands within an agricultural landscape	5
Changes in soil iron biogeochemistry in response to mangrove dieback	5
Temperature controls diel oscillation of the CO2 concentration in a desert soil	5
Biological nitrogen fixation and nifH gene abundance in deadwood of 13 different tree species	5
Elevated salinity and water table drawdown significantly affect greenhouse gas emissions in soils from contrasting land-use practices in the prairie pothole region	5
Drivers of soil respiration in response to nitrogen addition in a Mediterranean mountain forest	5
Inundation time mediates denitrification end products and carbon limitation in constructed floodplains of an agricultural stream	5
Sensitivity of soil organic matter to climate and fire in a desert grassland	5
A landscape approach to nitrogen cycling in urban lawns reveals the interaction between topography and human behaviors	5
Atmospheric deposition and precipitation are important predictors of inorganic nitrogen export to streams from forest and grassland watersheds: a large-scale data synthesis	5
Contrasting responses of DOM leachates to photodegradation observed in plant species collected along an estuarine salinity gradient	5
Partitioning benthic nitrogen cycle processes among three common macrofauna holobionts	5
Nitrogen dynamics after two years of elevated CO2 in phosphorus limited Eucalyptus woodland	5
Quantifying biological processes producing nitrous oxide in soil using a mechanistic model	5
Small rain events during drought alter sediment dissolved organic carbon leaching and respiration in intermittent stream sediments	5
Interannual changes in δ15N baseline in a lake–swamp–river food web: effects of summer precipitation in West Siberian forest steppe	5
Riparian seasonal water quality and greenhouse gas dynamics following stream restoration	5
Seasonal and weather-related controls on methane emissions from the stems of mature trees in a cool-temperate forested wetland	5
Water column contributions to the metabolism and nutrient dynamics of mid-sized rivers	5
Production of dissolved carbon and alkalinity during macroalgal wrack degradation on beaches: a mesocosm experiment with implications for blue carbon	5
Zooplankton release complex dissolved organic matter to aquatic environments	5
Biogeochemical feedbacks may amplify ongoing and future ocean deoxygenation: a case study from the Peruvian oxygen minimum zone	5
Plant invasion alters the Michaelis–Menten kinetics of microbial extracellular enzymes and soil organic matter chemistry along soil depth	5
Soil science in the time of climate mitigation	4
Carbon content of soil fractions varies with season, rainfall, and soil fertility across a lowland tropical moist forest gradient	4
Sensitivity of river catchments to discharge-controlled dissolved carbon export: a study of eight catchments in southern Patagonia	4
Mercury transport and fate in municipal solid waste landfills and its implications	4
Plant litter composition and stable isotope signatures vary during decomposition in blue carbon ecosystems	4
Soil greenhouse gas fluxes in floodplain forests of the Danube National Park: effects of flooding and soil microclimate	4
DOM in the long arc of environmental science: looking back and thinking ahead	4
Increased interactions between iron oxides and organic carbon under acid deposition drive large increases in soil organic carbon in a tropical forest in southern China	4
Patterns of foliar and soil nitrogen isotope composition of Caragana microphylla, a leguminous shrub species in the semi-arid regions of northern China	4
Temporal soil enzyme patterns provide new insights into the nutrient economy of acidic hardwood forests	4
Quantitative relationship between organic carbon and geochemical properties in tropical surface and subsurface soils	4
Characterisation of riverine dissolved organic matter using a complementary suite of chromatographic and mass spectrometric methods	4
Unexpected microbial metabolic responses to elevated temperatures and nitrogen addition in subarctic soils under different land uses	4
Differential subsurface mobilization of ambient mercury and isotopically enriched mercury tracers in a harvested and residue harvested hardwood forest in northern Minnesota	4
Patterns and controls of aboveground litter inputs to temperate forests	4
Spatial and seasonal variability of sedimentary features and nitrogen benthic metabolism in a tropical coastal area (Taganga Bay, Colombia Caribbean) impacted by a sewage outfall	4
Contrasting seasons and land uses alter riverine dissolved organic matter composition	4
Low denitrification rates and variable benthic nutrient fluxes characterize Long Island Sound sediments	4
Effects of experimental and seasonal drying on soil microbial biomass and nutrient cycling in four lowland tropical forests	4
Is the transactional carbon credit tail wagging the virtuous soil organic matter dog?	4
Post-fire effects of soil heating intensity and pyrogenic organic matter on microbial anabolism	4
Bio-weathering of granites from Eastern Dharwar Craton (India): a tango of bacterial metabolism and mineral chemistry	4
Pyrolysis temperature and soil depth interactions determine PyC turnover and induced soil organic carbon priming	4
Spatial and temporal patterns of benthic nutrient cycling define the extensive role of internal loading in an agriculturally influenced oxbow lake	4
The southwestern South Atlantic continental shelf biogeochemical divide	4
Patterns in riverine carbon, nutrient and suspended solids export to the Eastern James Bay: links to climate, hydrology and landscape	4
From canopy to consumer: what makes and modifies terrestrial DOM in a temperate forest	4
Fiddler crab burrowing increases salt marsh greenhouse gas emissions	4
Biogeochemical causes of sixty-year trends and seasonal variations of river water properties in a large European basin	4
Role of eddies and N2 fixation in regulating C:N:P proportions in the Bay of Bengal	4
Watershed Alnus cover alters N:P stoichiometry and intensifies P limitation in subarctic streams	4
Plant community effects on soil moisture and nitrogen cycling in a semi-arid ecosystem	4
Too much of a good thing? Inorganic nitrogen (N) inhibits moss-associated N2 fixation but organic N can promote it	4
The pedogenic Walker and Syers model under high atmospheric P deposition rates	4
Saltwater intrusion affects nitrogen, phosphorus and iron transformations under oxic and anoxic conditions: an incubation experiment	4
Priming effect in semi-arid soils of northern Ethiopia under different land use types	4
Impact of ecosystem water balance and soil parent material on silicon dynamics: insights from three long-term chronosequences	4