Preliminary Results of Sea Water Quality Assessment Based on Physiological Biomarkers in Part of the Boka Kotorska Bay

Rajko Martinović1, Anton S. Kurakin2, Sergey V. Kholodkevich2, Zoran Gačić3 and Zoran Kljajić1

 

 

1 Institute of Marine Biology Kotor (IMB), University of Montenegro, P.O. Box 69; 85330 Kotor, Montenegro; E-Mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

2 Saint-Petersburg Scientific Research Center for Ecological Safety, RAS-Laboratory of Experimental Ecology of Aquatic Systems (SRCES RAS-LEEAS), Saint-Petersburg, Russia

3 Institute for Multidisciplinary Research (IMSI), University of Belgrade; Serbia

 

 

Abstract

The new electrophysiological procedure for water quality assessment used in presented study is based on cardiac activity of the Mediterranean mussel (Mytilus galloprovincialis L.) and fiber optic non – invasive registration of the heart rate (HR) change. Time of recovery and coefficient of variation (CV) of the heart rate within a group of tested mussels calculated for data obtained after the stress test are being considered as a new biomarker of the physiological state. The Mediterranean mussels were sampled from three study sites of the Boka Kotorska Bay; one was used as the reference site, while the other two are considered as impacted. Since the average recovery times of HRs or CV for animals collected from the impacted sites exceed the values recorded on individuals from the reference site, the presence of stress is confirmed by the procedure used. However, the differences recorded are not significant. The method should be further elaborated (on the same and different species, as well as on an array of sites that are under the influence of different stressors) in order to be improved and effectively used as an early warning system for stress detection.

Keywords: physiological biomarkers, the Boka Kotorska Bay, cardiac activity of mussel

 

 

Introduction

The Boka Kotorska Bay is exposed to a considerable level of pollution (Joksimovic et al., 2001). The Bay is a complex semi-enclosed area that additionally contributes to the higher pollution pressure. Population growth and an increasing number of vessels have caused the presence of organic waste and other undesirable factors such as heavy metals and various chemical compounds in seawater.

Recently, the development of new techniques have permitted investigations carried out by means of on-line non-invasive methods of cardiac activity monitoring based on infrared light sensors (Depledge and Andersen, 1990). The contemporary biomonitoring methods based on physiological biomarkers are designed in order to improve the effectiveness of the monitoring practice.

There are different methods of a human heart rate (HR) regulatory stress level estimation, but the most developed and accepted is a mathematical analysis of HR variability, reflected in the reaction of an organism in general to any factors of an external or internal nature (Baevski, 1988).

The original approach (Kholodkevich et al., 2008) is based on an innovative fiber-optic method for registration and analysis of cardiac activity of benthic invertebrates. It is used for non-invasive heart rate (HR) registration of the test animal and for developing mathematical algorithms of electric signal processing and interpretation.

The Mediterranean mussels (Mytilus galloprovincialis L.) were used as test organisms since they were found to be an effective indicator of different stress conditions in the aquatic environment (Maanan, 2007; Mochino et al., 2011).

The initial assumption of the study was based on the fact that mussels placed in a polluted environment for a longer period of time have a much longer recovery time after a stress test than the mussels placed in conditionally clean water. Thus, higher values of the second biomarker – coefficient of variation, could indicate a more or less polluted area. Based on the previous, the aim was to make a comparison between calculated values of biomarkers within a group of tested mussels to estimate the water quality of the study areas.