Table 2.
Overview of parameters obtained from the SPI technique, acronyms, method or software used and type of variable (N numerical, C categorical)
| Parameter type | Parameters | Acronym | Obtention method | Type |
|---|---|---|---|---|
| Overall sediment features | Mean penetration depth (of the SPI device plate into de sediment); linked to sediment compactness (Rhoads & Germano, 1982) | MPD | SpiArcBase | N |
| Sediment-water interface (SWI) length | SWI | ImageJ | ||
| Median grain size | MGS | Observation | C | |
| Biogeochemical features | aRPD (mm) | RPD | SpiArcBase | N |
| Maximum depth aRPD (mm) | mRPD | SpiArcBase | N | |
| SPI width | W | SpiArcBase | N | |
| Percentage of anoxic sediment | AA% | Calculation*1 | N | |
| aRPD range | rRPD | Calculation*2 | N | |
| Length of the aRPD | lRPD | ImageJ | N | |
| Biological features | Presence (P.) of biogenic beds (mainly L. conchilega) | BIOB | Observation | C |
| P. of surface fauna | SF | Observation | C | |
| P. of faecal Pellets | FP | Observation | C | |
| P. of feeding mounds or pits | FMP | Observation | C | |
| No. infaunal organisms | INF | Observation | N | |
| No. Burrows | BN | Observation | N | |
| No. Surface fauna (per species) | SF_n | Observation | N |
In bold: variables used in the mixed multivariate matrix for FDMA analysis
*1AA% = anoxic sediment area/total sediment area*100
*2rRPD = |mRPD| − RPD*2