Document of bibliographic reference 62115

BibliographicReference record

Type

Bibliographic resource

Type of document

Journal article

BibLvlCode

AS

Title

Abnormal features of M. balthica (Bivalvia) in the Baltic Sea: alerting symptoms of environmental adversity?

Abstract

Recent studies of the Baltic clam Macoma balthica (L.) from the southern Baltic (the Gulf of Gdansk) have revealed striking morphological, histological and cytogenetic features. Strong deformation of the shell, including elongation of the posterior end and the appearance of an easily visible flexure in this part, has been recorded. The population contribution of the deformed blunt shelled (“irregular”) clams ranged from 0% to 65% and tended to increase with depth. The morphologically “irregular” clams had higher accumulated tissue concentrations of trace metals (As, Ag, Cd, Pb, Cu and Zn), indicating a different metal handling ability. Adverse conditions in deeper water regions of the Gulf (e.g. hypoxia, hydrogen sulphide, elevated bioavailability of contaminants) have been suggested as inducers of the phenotypical changes (morphological deformation) in part of the population and, in parallel, of the specific physiological adaptations that result in higher metal accumulation in the “irregular” clams. Cytogenetic and histological analyses showed the presence of tumours in gill cells and digestive system of the affected clams, the prevalence of disseminated neoplasia ranging from 0% to 94% depending on the site. The disease was manifested by a modified karyotype (i.e. an abnormal number and morphology of chromosomes), a higher activity of nucleolar organizer regions (AgNORs), and tissue lesions (enlarged cells, actively proliferative with pleomorphic nuclei). Bottom sediments showed acute toxicity and have been proposed as a source of an initialising carcinogenic factor. However, none of the ecotoxicological studies provided was successful in the clear demonstration of a single (or multifactorial) agent that can account for the disseminated neoplasia.

Bibliographic citation

Sokolowski, A.; Wolowicz, M.; Hummel, H.; Smolarz, K.; Fichet, D.; Radenac, G.; Thiriot-Quievreux, C.; Namiesnik, J. (2004). Abnormal features of M. balthica (Bivalvia) in the Baltic Sea: alerting symptoms of environmental adversity? Mar. Pollut. Bull. 49(1-2): 17-22

Topic

Marine

Is peer reviewed

true