Table 3 Summary of CO2 impact on benthic organisms and processes at the Basiluzzo Islet sites (soft sediments) and comparison with available benthic data from other shallow natural CO2 vents (soft and rocky seafloor) at Ischia, Vulcano, and Papua New Guinea.

Significant deviations from the REF are described by upward (enhancing) or downward (declining) arrows, respectively, or by + for changes in community structure. 0, neutral; PNG, Papua New Guinea; OC, organic carbon; EEA, extracellular enzymatic activity; Undist., undisturbed sediments at CO2 vents; Transpl., medium-term (1 year) transplanted sediments from reference to CO2-impacted site (REF/CO2-R). For references and detailed description of CO2 affects on marine environments at natural CO2 vents, see table S9.

BasiluzzoIschiaVulcanoPNG
Undist.Transpl.
InvertebratesCommunity structure+++na+
Abundance↑↓na
Biomassnana
SeagrassDensity0na↑/0
Biomassnanana
Photosynthetic activitynana0
MacroalgaeCommunity structurenana+na+
Community structure+nana+na
MicrophytobenthosAbundancenanana
Biomassnana
BacteriaCommunity structure++na++
Abundance00nanana
Primary production and OC remineralizationOxygen productionnananana
Oxygen respirationnananana
SRRnanana
OC degradationβ-glucosidase (EEA)nanana
Esterase (EEA)nanana
Nutrients fluxSilicate, ironnanana