State-of-the-Art of Monitoring Methods to evaluate Storage Site Performance

 
1. INTRODUCTION
 
2. MONITORING TECHNIQUES
 
3. MONITORING CONCEPTS – STATUS QUO
 
4. SETTING UP A SITE-SPECIFIC MONITORING PLAN
 
5. CONCLUSIONS AND RECOMMENDATIONS
 
6. REFERENCES
 
 
2.1 CO2 plume migration in the storage reservoir
 
2.2 Surface uplift
 
2.3 Induced seismicity and mechanical reaction of overburden
 
2.4 Faults
 
2.5 Abandoned wells
 
2.6 Overlying and adjacent aquifers
 
2.7 Freshwater aquifers
 
2.8 Near surface eco-compartments
 
 
2.8.1 Soil and Seabed Gas Monitoring
 
2.8.2 Atmospheric Monitoring
 
2.8.3 Tracers – natural and introduced
 
2.8.4 CO2 detection in shallow subsurface
 
2.8.5 Vegetation stress and changes
 
» 2.8.6 Biological monitoring
 
 

2.8.6 Biological monitoring

The impact of increasing CO2 concentrations in the soil column on plants, microorganisms or invertebrates due to upwardly migrating gas has been examined by several studies at sites of natural CO2 emanations (e.g. Beaubien et al., 2008; Macek et al., 2005; Pfanz et al., 2007; Oppermann et al., 2010). According to all studies, increased CO2 concentrations in the soil lead to changes in the vitality, abundance and diversity of plants, invertebrates and microorganisms. It is also recognised that diverse factors, besides CO2 concentration in the soil column, affect biological systems. The impacts of leaking CO2 are usually restricted to spots of a few square metres only, which often represent the cores of venting areas where the highest soil CO2 concentrations exist (cf. Fig. 2-19).

Fig _2_19Fig. 2-19: Idealised geoecological conditions around a natural CO2 vent at the western shore of Lake Laach, Germany (from Möller, 2008). Abundances of bacteria, sulfate-reducing bacteria and archaea are given in relative numbers; vegetation composition with Polyg. = Polygonum arenastrum, DICot. = other DICotyledons, Grass = grasses in total.

Numerous other experimental field and lab studies, which were often ecologically and/or physiologically oriented, have contributed to a broad and diversified knowledge of direct and indirect impacts of elevated CO2 concentrations on different scales, from single organisms to entire life communities, for example, for invertebrates (e.g. Zaller and Arnone, 1999; Loranger et al., 2004; Asshoff, 2005), and even for small animals (e.g. Blackshaw et al., 1988; Leach et al., 2002; Niel and Weary, 2006).

Several studies have been published regarding the effect of increased atmospheric CO2 concentrations on ecosystem levels (e.g. Jossi et al., 2006; Calfapietra et al., 2009; NIPCC, 2011), where, once again, specific elevated concentrations and the exposure time to these concentrations are very important for particular impacts.

Knowing the potential impacts, investigating the condition/status of different species, communities or of ecosystems can provide indications for areas of high CO2 concentrations in the soil (e.g. Pfanz et al., 2007; Krüger et al., 2011). Similar approaches can be applied to the monitoring of the marine environment (e.g. Beaubien et al., 2008; Widdicombe et al., 2009; Karuza et al., 2012).