@article{fdi:010048397,
  title = {{R}elevance and limitations of biogenic and physicogenic classification : a comparison of approaches for differentiating the origin of soil aggregates},
  author = {{J}ouquet, {P}ascal and {Z}angerle, {A}. and {R}umpel, {C}. and {B}runet, {D}idier and {B}ottinelli, {N}. and {T}ran {D}uc, {T}.},
  editor = {},
  language = {{ENG}},
  abstract = {{A}lthough freshly formed or unaltered biogenic aggregates are easily recognized, identifying the origin of aggregates altered by physical and biological processes remains empirical and prone to error. {T}he aim of this study was to distinguish between biogenic ({BIO}) and physicogenic ({PHYS}) aggregates in various states of fragmentation or size classes using visual, physical and chemical characteristics. {C}asts produced by {A}mynthas khami ({BIO}) and surrounding soil aggregates without visible biological activity ({PHYS}) were left to disaggregate by natural rainfall events and then separated into five size classes of > 10, 10-5, 5-2, 2-0.5 and < 0.5 mm. {W}e then analysed aggregate morphology, elemental and stable isotope composition and soil stability, and used near-infrared spectroscopy ({NIRS}) to determine their chemical characteristics. {A}lthough visual assessment is the method most commonly used in the field to distinguish between {BIO} and {PHYS}, our study found that the results obtained were always prone to error and that the classification was arbitrary for {BIO} and {PHYS} aggregates smaller than 5 and 2 mm in size, respectively. {S}oil structural stability was only useful for identifying {BIO} aggregates larger than 2 mm. {W}hile {C} content and delta 13{C} in {BIO} were always different from {PHYS}, regardless of soil aggregate size, {N} content and delta 15{N} were similar. {NIRS} was the most effective method because it clearly discriminated soil aggregates on the basis of size and origin. {T}he {NIRS} characteristics of {BIO} were also more uniform than those of {PHYS}, suggesting that {BIO} aggregates have a simpler organization and as a consequence more homogeneous ecological functions. {T}hus, our findings suggest that information may be lost when only the physical aspect of aggregates is used to quantify the activity of ecosystem engineers in soil. {A}fter fragmentation, {BIO} aggregates become hidden and although it may be impossible to distinguish them visually from {PHYS} aggregates they retain some of their specific chemical characteristics.},
  keywords = {},
  booktitle = {},
  journal = {{E}uropean {J}ournal of {S}oil {S}cience},
  volume = {60},
  numero = {6},
  pages = {1117--1125},
  ISSN = {1351-0754},
  year = {2009},
  DOI = {10.1111/j.1365-2389.2009.01168.x},
  URL = {https://www.documentation.ird.fr/hor/fdi:010048397},
}