The methodology of HOTSPOT includes the use of existing data, sampling of new data, laboratory experiments, statistical modelling and dissemination.
Pollutants to be investigated
HOTSPOT has a focus on the environmental effects of heavy metals (V, Ni, Pb, Cu, Cd, Zn, Hg, Cr, Ba), oil compounds and marine litter (including micro-plastics), in combination with the stress caused by increasing sea surface temperature.
Maritime pollution in the coastal areas interacts with the land-based pollutants such as mining, industrial and municipal waste, and increasing sea surface temperature will influence the way organisms respond to pollutants. Maritime pollutants will thus need to be considered in the context with land-based pollution and climate change.
Existing data and new samples
To investigate the relative contributions of onshore and maritime/offshore activities to pollution, we combine a sector assessments based on the available scientific and statistical data and expert-judgements for gap-filling, with a sampling campaign covering approx. 10 stations in the coastal waters of Ghana. The sampling will include monthly measurements of hydrography nutrients, phytoplankton, microbes and zooplankton. Sampling will be conducted from local fishing boats.
Laboratory experiments
To investigate the cumulative effects of stressors and the mechanisms behind species responses, we will conduct laboratory experiments measuring mortality, feeding, respiration and reproduction of key zooplankton species in a relevant range of concentrations of contaminants and their mixtures, and including 2-3 different temperatures. The contaminants to be investigated will be chosen based on the analysis of contaminant sources.
The bottle incubations with single species will be up-scaled to population and community levels. This will be done both using a mechanistic model and experimentally, in so-called mesocosms experiments. Mesocosms experiments will be conducted in > 100-l land-based containers, with an enclosed natural plankton community manipulated by contaminants.
Statistical modelling
Simple statistical models and individual-based models will be used for synthetizing the data, and can be included as modules in the more complex ecosystem models. In addition, data and insights obtained through the project will be synthetized in a conceptual model which will help to focus management actions to particularly sensitive seasons and areas, and will form a dissemination tool to authorities.
Dissemination
HOTSPOT strives to disseminate and communicate its research to multiple audiences ranging from school pupils to research students, as well as to ensure maximum exploitation of its results by policy-makers.