Common use of Nutrients Clause in Contracts

Nutrients. Nutrients cannot be directly measured using EO optical or thermal data. In-situ data may, however, be useful for validating measures of algal and cyanobacterial biomass as they are highly correlated. The measurement of nutrients in water is a quantitative measure that typically depends on highly developed and sensitive field equipment. It is, therefore, one of the more difficult measurements to deliver through CS sampling campaigns without relatively expensive equipment. The largest CS campaign to produce nutrient data is Freshwater Watch with data from 2,500+ sites globally, with some datasets more than a decade long. The test kits used by FWW produces a categorical classification for a sample’s nitrate or phosphate concentration using colorimetric methods. For example, for nitrate citizens identify the nitrate concentration within seven specific classes ranging from 0.2 to 0.5, 1, 2, 5 and 10.0 mg/▇. ▇▇▇▇▇ and ▇▇▇▇▇ (2017) argued that even though FWW data on nutrient concentrations could be useful to see patterns on a global scale, there were limitations of class-based classification for finer scale analysis. This semi-quantitative data could, however, potentially be used for validation of EO-derived measures of algal biomass, if chlorophyll-a or cyanobacteria data did not exist. Data was directly available from portals or websites in seven schemes; five schemes had data available upon request and acknowledgement or by membership (potentially unpaid); 13 had either an online data explorer or no clear indication of data availability (Table 7). • Parameters missing from CS schemes: DOC and limited for Chlorophyll-a and nutrients • Poorly monitored regions – bias to USA and Australia • Temporal coverage – few long-term datasets Our literature and data review has outlined a number of opportunities to be further examined: • Better communication lines between CS and EO communities to improve data collection and use of both CS and EO data by both communities • Developing tailored CS schemes specifically to support development of EO data products • Better (cross-)validation of EO and CS data products • New smartphone sensors to support high quality data collection e.g. iSpex-2 There are also some specific partnerships which merit further consideration where better communication could lead to benefits for both EO and CS communities: o Turbidity products: engaging with Secchi dip-in o Harmful algal blooms of cyanobacteria: engaging with Bloomin’ Algae o Water colour and cDOM: engaging with Eye on Water