|Where did Marenzelleria spp. (Polychaeta: Spionidae) in Europe come from?|
Bastrop, R.; Röhner, M.; Sturmbauer, C.; Jürss, K. (1997). Where did Marenzelleria spp. (Polychaeta: Spionidae) in Europe come from? Aquat. Ecol. 31(2): 119-136
In: Aquatic Ecology. Springer: Dordrecht; London; Boston. ISSN 1386-2588, more
|Authors|| || Top |
- Bastrop, R.
- Röhner, M.
- Sturmbauer, C.
- Jürss, K.
Abundant populations of Marenzelleria spp. were reported for the first time in the North Sea during the late 1970s and then in the Baltic Sea in 1985. Genetic analysis by means of allozyme electrophoresis and sequencing of a segment of mitochondrial 16srDNA showed that two different genetic types or sibling species of Marenzelleria were present in Europe. Marenzelleria Type I is found only in the North Sea, whereas Type II has been found in both the North Sea and the Baltic Sea. The North Sea animals (Type I) correspond to Type I specimens found in North American coastal waters between Nova Scotia and Cape Henlopen (Delaware), while Marenzelleria Type II from the Baltic Sea correspond to Marenzelleria type II animals from the Arctic (Tuktoyaktuk Harbor, Northwest Territories, Canada), New Hampshire and coastal waters between Chesapeake Bay southward to the Ogeechee River (Georgia). Human mediated introduction (by shipping) and natural range expansion are discussed as the possible causes of these virtually simultaneous invasions by two sibling species. Marenzelleria Type I appears to colonize habitats with a higher salinity and/or in which salinities tend to fluctuate considerably. The osmolality of the coelomic fluid after acclimation to various salinities between 0.25 and 18‰ is the same for both sibling species/genetic types. Although the two types do not differ in respect of hyperosmoregulation (<10‰), differences may exist in their cell volume regulation or its time course in the almost isoosmotic range at salinities >10‰.