Impact of Sedimentary Fluxes of Algal Blooms on the Bioaccumulation and Biomagnification of Persistent Organic Pollutants

FONDECYT 1210946

Persistent organic pollutants (POPs) reach Antarctica through atmospheric transport, oceanic
currents, and to minor extent, by migratory animals. The Southern Ocean is a net sink for many POPs with a key contribution of the settling fluxes of POPs sorbed to organic matter (biological pump). It has been demonstrated that the sink of organic matter due to high primary production events (phytoplankton blooms) plays a key-role affecting the fluxes between atmospheric and hydrospheric compartments as demonstrated by global models and in-situ studies. However, little is known about the influence of this sinking fluxes on POPs transfer through the food web in the Southern Ocean, where krill is an important ecological key node. Previous studies, from the PI, suggested that high exportation fluxes of organic matter due to phytoplankton bloom periods affects the bioaccumulation and the subsequent biomagnification from primary producers to grazers (lower trophic levels). But this conclusion was only based on a little amount of samples dispersed in different locations. This leads to our research team to ask us if this process is effectively occurring. To tackle this question we hypothesized that “The phytoplankton biological pump prevents the transfer of POPs trough the food web due to higher sedimentation fluxes from surface to sediment during high productive periods”. The rationale of the project is that, during high productivity periods, POPs are effectively transferred to sediments due to high sedimentation fluxes compared to biomagnification of POPs and Emergent compounds to Krill and other macroinvertebrates and in consequence to higher trophic levels.

To achieve this, we propose the following specific objectives:

1. To measure the concentration and phase distribution of different pollutant families selected POPs
   like Polychlorobiphenyls (PCBs), Hexachlorocyclohexanes (HCHs) and Hexachlorobenzene (HCBs) and Polybromodiphenyl ethers (PBDEs) in air, water, phytoplankton, zooplankton and sediment traps using active sampling.
2. To measure the Dissolved Organic Carbon (DOC), the Particulate Organic Carbon and Particulate
   organic Nitrogen (POC and PON) in the sinking particles and the Organic Carbon and Organic Nitrogen (OC and ON) content in the biota (phytoplankton and zooplankton collected) and sediment traps including the isotopic ratio (δC13 and δN15).
3. To estimate the air-to-water estimation fluxes by using two film model.
4. To estimate the water to sediment sedimentation fluxes of selected organic pollutants using the
   sediment trap results based on (POC).
5. Calculate the Bioconcentration, Bioaccumulation and Biomagnification using the water,
   phytoplankton and zooplankton in relation to the concentration of organic carbon present in the dissolved phase, phytoplankton and zooplankton.
6. To apply a multimedia fate model to estimate POPs fate in the water-column.