Morphological Deformation of Foraminiferal Tests Caused by Intertidal Oil Spills (Black Tides)

Marie-Thérèse Vénec-Peyré (1) , Annachiara Bartolini (1) , Michele Weber (2) , Jere Lipps (2)

1 CR2P - Centre de Recherche en Paléontologie - Paris
2 Museum of Paleontology, University of California, Berkeley, CA

The causes of morphological foraminiferal test deformations (chamber malformations, errors in directional growth) have been extensively studied for a long time. Such deformations are found in areas of pollution, including oil spills, or “black tides” in tidal regions. Nevertheless, questions have arisen on whether or not deformed foraminifera are a bioindicator in such ecological catastrophes. This study compares, for the first time, the impact of the Amoco Cadiz (1978) and Erika (1999) oil spills on foraminifera in two close areas, the Bay of Morlaix and Bay of Bourgneuf, NW France. In these similar environments (mud flats of tidal areas) with similar faunas (characterized by the foraminifera Haynesina germanica), the foraminiferal response to oil pollution was different. During the 13 months following the Amoco Cadiz black tide (1978), foraminiferal deformations increased (from 3 to 21%) while after the Erika black tide (1999) their ratios did not exceed those observed in non-polluted areas (3%). In addition, turbellarians (flatworms) increased their attachment of egg capsules to foraminiferal tests in Amoco Cadiz black tide areas. We review and compare the causes of such differences in the response of foraminifera to oil spills by examining the main characteristics of both black tides (magnitude of the spills, the physical and chemical properties of discharged oils, their concentration in the studied sediments, as well as the characteristics of the spill context). This analysis shows that both studies on deformed foraminifera, far from contradicting each other, only emphasize the differences between the characteristics of Amoco Cadiz and Erika oil spills. Deformed foraminifera are good indicators of the severity of oil spill impact and the rate of recovery after such a disaster.

Mots clés: Foraminifera; Pollution; Environmental stress; Black tides; Morphological deformations

Domaines: Planète et Univers [physics]

Marie-Thérèse Vénec-Peyré, Annachiara Bartolini, Michele Weber, Jere Lipps. Morphological Deformation of Foraminiferal Tests Caused by Intertidal Oil Spills (Black Tides). Morphogenesis, Environmental Stress and Reverse Evolution, Springer International Publishing, pp.175-196, 2020, ⟨10.1007/978-3-030-47279-5_9⟩. ⟨mnhn-03980871⟩