LER des Pertuis Charentais

History

• Earliest observation of foraminifera
• The colossal work of Alcide d'Orbigny on foraminifera
• Modern classification of foraminifera
• Recent studies of coastal benthic foraminifera
  • Ecological interest
  • Pollution effects on foraminifera

Earliest observation of foraminifera

• From the antiquity, Hérodote (V century before J.-C.), Strabon (63 before J.C. - 20 after J.C.) and Pline the Older (23 - 79 after J.C.), was noticing accumulation of lentil-like form numerous in the calcareous of the Giza pyramids in Egypt. It was a fossil foraminifera Nummulites.
• The organic origine of the creature was discovered in the XV century by Leonardo da Vinci or in the XVI century by Agricola. Linaeus in his "Histoire naturelle" (1766) recognized 15 species of foraminifera. At the end of the XVIII century and the early beginning of the XIX century, numerous publication are written by Soldani, Fichtel and Moll, Lamarck, Defrance, De Blainville,…

The colossal work of Alcide d'Orbigny on foraminifera

• Work of d'Orbigny on foraminifera was considerable. When he was young he was already highly interested in the study of a group of microscopic animals, that he named "Foraminifers".
• After observing near to 600 species both fossils and living Alcide d'Orbigny first proposed a classification of the foraminifera (1826): "Tableau méthodique de la classe des Céphalopodes", since modified many times. It is based on morphological characteristics and own 5 families, 52 genus and 552 species. He illustrated this work by 73 plates whom numerous are still unpublished.
  
• He also created 3-D calcareous specimens enlarged 40 to 200 times.
• He commercialized plaster copies all over the world. By this work he dug the foundation of Micropaleontology.
• Nevertheless in the latter half of the 18^th century and until 1835, most foraminifers were described as cephalopods (particulary as Nautilus such as Linaeus). This is Felix Dujardin (1835) who demonstrated that foraminifers were unicellular organisms and not cephalopods and considered them as protozoa.
• d'Orbigny completed is work by numerous description in the les Foraminifères de l'île de Cuba (1839) and les Foraminifères des îles Canaries (1840) and les Foraminifères de l'Amérique méridionale (1839-1841).

Modern classification of foraminifera

• The mostly used classification today is the one established by Loeblich and Tappan (1988). The authors considered foraminifers as an order in the sub-class of Granuloreticulosa, class Rhizopoda, phylum protozoa. They distinguished 12 sub-order after the nature of the test (shell) and the formation method, 74 superfamilly after the internal nature and the spatial distribution of the chambers, and after apertures, 296 families, 302 sub-families and 2446 genera.
• Nevertheless this world wide classification do not take in account biology of foraminifera as biological studies began at the end of the XIX century but only developed in the 1980s. Such a classification based on DNA analysis would raised in the near future.

Recent studies of coastal benthic foraminifera

• Ecological interest
  • Foraminifera are among the more abundant and most conspicuous protozoa in most marine and brackish water habitats. Many species have durable shells (tests), which are an important component of marine and paralic sediments (Lee et al., 2000). Because foraminifers have a short life cycle, they react quickly to environmental settings variations and can be used as an early warning indicator, as defined by Kramer and Botterweg (1991).
  • Even if their growth follows a yearly cycle, their mineralized tests remain in the sediments and give an average picture of the assemblages, and therefore of the ecological conditions, despite the great annual or even inter annual variability. Foraminiferal assemblages are easy to collect, and are often found in high-density populations, providing an adequate statistical base (even in small volume samples).
  • Salinity-tolerant coastal and paralic foraminifera have first been used as salinity indicators in the standard estuarine classifications based on the spatial distribution of salinity from oceanic to continental end members (e.g., Nichols, 1974), but they are also well adapted for environmental monitoring (Scott et al., 2001). When pollution is suspected, they may serve as a mean of judging whether costly comprehensive studies should be initiated.
• Pollution effects on foraminifera
  • Studies of pollution effects on benthic foraminifera and of the possible use of these organisms as proxies were initiated by Resig (1960) and Watkins (1961), although pollution effects on foraminifera had been mentioned earlier by other workers (e.g., Zalesny, 1959). Throughout the last few years, many studies dealing with benthic foraminifera as bioindicators of coastal pollution have been carried out (review in Boltovskoy et al., 1991; Alve, 1995b; Yanko et al., 1999; Scott et al, 2001). An entire volume of the Journal of Foraminiferal Research was devoted to this problem in 1995.
  • Most of the papers focussed on the effects of pollution upon foraminiferal distribution and morphology and dealt with domestic and agricultural wastes (Watkins, 1961; Seiglie, 1968; Schafer, 1970, 1973; Schafer and Cole, 1974; Seiglie, 1975; Setty, 1976; Bates and Spencer, 1979; Setty and Nigam, 1984; Alve and Nagy, 1986; Ellison et al., 1986; Nagy and Alve, 1987; Alve, 1991a; Yanko and Flexer, 1992; Yanko et al., 1994), paper mill effluent (Schafer 1970, 1973; Buckley et al., 1974), oil spill (Seiglie, 1968, Alve 1995b), or trace metals in sediments (Alve, 1991a; Sharifi et al., 1991; Alve and Olsgard, 1999; Debenay et al., 2001b; Armynot du Châtelet et al., 2004). They concluded that foraminifera are very sensitive to pollution.
  • Foraminifera should be applied as part of integrated programs of pollution monitoring, including chemical analysis of the contaminants. Their uses should include routine long-term surveillance programs, hazard assessment at specific discharge sites, and monitoring of the effectiveness of remedial actions (Debenay et al., 2000).