Forsøksdyr: Acute and long-term effects of burned oil residues on Northern shrimp (Pandalus borealis)

Godkjenningsdato 21.02.2020

Godkjenningsperiode 21.02.2020-06.06.2020

This work is part of the ARCEx project financed by NFR and industry partners and hosted by UiT Norway. NORCE Environment is partner in WP3 on the effect of petroleum discharges on key species of northern ecosystems.

The objective of this study is to gain knowledge on acute (LC50) and long-term effects of burned oil residues on pelagic (larvae) and benthic (adults) life stages of Northern shrimp (Pandalus borealis).

In-situ burning (ISB) is one of the oil spill responses (OSR) in offshore environments, particularly relevant for the Northern areas. It basically involves removal of oil by burning the spilled oil on the sea surface. The released oil is rapidly converted into combustion products while a small percentage of unburned oil and burned residues remain on the surface, within the water column, or sink to the seafloor (Bullock et al., 2019). ISB may increase the concentrations of large poly-aromatic hydrocarbons (PAHs; high ring number), while reducing small PAHs (low ring number) (Fritt-Rasmussen et al., 2015). Burned residues, either floating or sinking, may pose a risk of toxicity or contamination to organisms in the water column and on the seafloor. Floating residues may be ingested or cause fouling of gills (Fritt-Rasmussen et al., 2016), while sinking residues may affect benthos, mainly via smothering (NOAA, 2019). Acute aquatic toxicity of burned residues has been reported to be low (NOAA, 2019). However, Faksness and Altin (2019) found that the acute specific toxicity of WAF of ISB residue was more toxic to Calanus finmarchicus nauplii than WAF of fresh oil after 72 h exposure using an ultra-low sulphur fuel oil. Knowledge on chronic toxicity and long-term effects of burned residues on benthic and pelagic marine organisms / life stages is largely missing. We propose to use the Northern shrimp Pandalus borealis, an ecologically and economically important species in Norwegian waters, to address this knowledge gap. Firstly, during their life cycle, both pelagic and (epi-)benthic stages are present. Secondly, this species has repeatedly been shown to be sensitive to oil exposure (Arnberg, 2015; Arnberg et al., 2018; Bechmann et al., 2010; Taban et al., 2007). Effects prolonged beyond exposure during recovery (Arnberg et al., 2019; Keitel-Gröner et al., 2020), an aspect largely ignored in standard toxicity testing. Thirdly, the species has been shown to be suitable for laboratory work and NORCE researcher have many years of experience working with both, larval (pelagic) and adult (epibenthic) stages.

In total 240 adult shrimp are needed, 200 of these will be used in exposure experiments, while 40 adult shrimp are needed to provide larvae for exposure experiments. Additionally, 4380 larvae will be used, 3900 during exposure experiments and the remaining 480 to study carry-over effects on shrimp larvae exposed as embryos.

There are currently no effective replacement methods available to avoid the use of shrimp in this project. The minimum number of animals required to achieve acceptable statistical strength will be used.