Sediment health assessment using cell and tissue level
biomarkers in the polychaeta Nereis diversicolor
O. Romo, U. Izagirre, B. Zaldibar
CBET Research Group, Dept. Zoology and Animal Cell Biology;
Research Centre for Experimental Marine Biology and Biotechnology PIE-UPV/EHU.
University of the Basque Country UPV/EHU. Leioa. Basque Country. Spain.
*Presenting author contact: benat.zaldibar@ehu.es
Estuarine environments constitute transition zones where freshwater mixes with
seawater leading to high biological productivity and are generally exposed to important
urban and industrial activities responsible for numerous perturbations. It is well
established that sediment is one of the main reservoir for most of the chemicals
introduced in aquatic environments by human activities. Therefore, species inhabiting
sediments are particularly exposed to chemical stress. The ragworm Nereis
diversicolor is a common polychaete living in coastal and estuarine habitats and is an
important food resource for many estuarine species and consequently, has a key role
in the functioning of coastal and estuarine ecosystems. In the present work sediments
of three different estuaries in the Basque Country (Butroe -reference site-, Nerbioi and
Oiartzun -polluted sites-) were collected, transported to the lab. Ragworms were
purchased in a local market and let burrowed into the sediments for 1 and 7 days.
Physicochemical parameters were calculated during the experimental period including
pH, salinity and temperature. Samples of the sediments, water and ragworms were
collected for chemical determination of heavy metals. On the other hand, ragworms
were also collected after 1 and 7 days of exposure for biological analysis including
changes in size and weight and cell and tissue level measurements such
histopathological alterations, changes in the oocyte size, alterations in mucocytes of
the tegument, digestive tube alterations and lysosomal changes. Preliminary results in
organism level alterations indicated that in sediments from the estuary of Butroe there
were no significant differences in biometric parameters. However, in sediments from
Nerbioi there were differences in weight and size, indicating growth and increased
weight after seven days of burrowing. Finally, in the Oiartzun estuary some differences
were observed in length, with an increase, but there were no differences in weight
changes. Regarding histopathlological alterations, we observed that there were
differences between the controls and the ragworms exposed to sediments. In general,
burrowed ragworms in the sediments from the three sites presented altered digestive
tract with a loss of digestive folds.
Acknownledgements: Work funded by The University of the Basque Country
UPV/EHU (UFI 11/37) and Basque Government through Consolidated Research
Groups fellowship (IT810-B).