Effect of salinity on spatial distribution and cell volume regulation in two sibling species of Marenzelleria (Polychaeta: Spionidae)

Abstract

Marenzelleria sibling species Types I and II are characteristically distributed within the salinity gradient of the Elbe estuary. For the first time F 1 -hybrids between the 2 Marenzelleria species were found. Type I inhabits mainly the isoosmotic/hyperosmotic range, while Type II and the F 1 -hybrids prevail in the hypoosmotic range. A sympatric occurrence could be inferred in salinity ranges from 3.3 to 12.3 ppt. Marenzelleria sibling species Type II has been found for the first time in the North Sea (Elbe estuary). The influence of salinity on the distribution of Marenzelleria spp. was examined by laboratory experiments. In a time-course experiment with salinity changes from 10 to 25 ppt and from 25 to 10 ppt, respectively, enzyme activities and free amino acids were determined. The activities of alanine aminotransferase, aspartate aminotransferase, and glutamate dehydrogenase were always higher in Type I than in Type II. A salinity increase from 10 to 25 ppt resulted in a faster increase of the concentrations of D,L-alanine, glycine, serine, glutamate and threonine in Type I. The biochemical results showed that the capacity of cell volume regulation could be involved in the different spatial distributions of the 2 sibling species.

Macrobenthic community response to the Marenzelleria viridis (Polychaeta) invasion of a Danish estuary

“…Both the historical (MV-invasion) and current spatial (MANspatial) distribution of M. viridis in Odense Fjord could arise from the limits of its environmental tolerance. It was not found at 2/3 of the stations in the inner part of the estuary where the low winter salinity (< 5 psu) probably was beyond its physiological range (George 1966, Bochert 1997, Blank et al 2004). The distribution of M. viridis in the outer estuary could be regulated by sediment conditions as salinity in this area remains >15 psu at all seasons.…”

“…This occurred for M. viridis near the shipping channel in the inner part of Odense Fjord in 2002. Its pelagic larvae may have been introduced through the release of ballast water from ships or brought by the subsurface inflow of high saline seawater from the connecting sea (Blank et al 2004, Josefson & Hansen 2004. The second phase is a lag period where the newly established species after a successful introduction maintains a low but stable population for some time (Essink & Dekker 2002.…”

“…This is probably the result of a biological capacity of this species to establish successfully in new areas (Ricciardi & Rasmussen 1998). Species of the genus Marenzelleria have the required tolerance (Hahlbeck et al 2000, Blank et al 2004) to withstand salinity fluctuations and exposure to anoxia or even sulfidic events that are common in Danish estuaries (Conley et al 2000). Furthermore, it has a high reproductive capacity (Essink & Kleef 1993) …”

Genetic Diversity and Expanding Nonindigenous Range of the Rhizocephalan Loxothylacus Panopaei Parasitizing Mud Crabs in the Western North Atlantic

“…These are species with no definite evidence of their native or introduced status (Carlton, 1996) or, in other words, hypothesized introductions with few data bearing on origins. Cryptogenic invasions have a high research priority when they have severe consequences (Burreson et al, 2000;Hoppe, 2002;Gozlan et al, 2005) or when they can be particularly instructive about biotic and abiotic mechanisms controlling invasion (e.g., Bastrop et al, 1998;Jousson et al, 1998;Blank et al, 2004). It is in this arena that molecular markers provide a crucial tool for the study of invasions, both because genetic diversity is an attribute that can change during invasion and may affect survival (Tsutsui et al, 2000;Lee, 2002), and because genetic polymorphisms provide tags that help trace invasion history (Geller et al, 1997;Jousson et al, 1998;Davies et al, 1999).…”

Impacts of changing climate on the non-indigenous invertebrates in the northern Baltic Sea by end of the twenty-first century

“…M. viridis may be limited to more saline areas and has only been found in the Gulf of Riga and south-western Bothnian Sea in the northern Baltic Sea (Bastrop and Blank 2006;Blank et al 2008). In tidal areas M. neglecta is known to prefer lower salinities than M. viridis (Blank et al 2004). M. arctia in its native region occurs in river estuaries where the salinity varies from freshwater to almost full salinity (Jørgensen et al 1999), but the reproduction and recruitment most likely take place during winter when intrusions of saline water occur (A. Maximov, Zoological Institute of Russian Academy of Sciences, pers.…”