Process length variation of the cyst of the dinoflagellate Protoceratium reticulatum in the North Pacific and Baltic‐Skagerrak region: calibration as an annual density proxy and first evidence of pseudo‐cryptic speciation

Abstract

Process length variation of cysts of the dinoflagellate Protoceratium reticulatum (Claparède et Lachmann) Bütschli in surface sediments from the North Pacific was investigated. The average process length showed a significant inverse relation to annual seawater density: σt annual = −0.8674 × average process length + 1029.3 (R2 = 0.84), with a standard error of 0.78 kg m−3. A sediment trap study from Effingham Inlet in British Columbia revealed the same relationship between average process length and local seawater density variations. In the Baltic–Skagerrak region, the average process length variation was related significantly to annual seawater density: σt annual = 3.5457 × average process length − 993.28 (R2 = 0.86), with a standard error of 3.09 kg m−3. These calibrations cannot be reconciled, which accentuates the regional character of the calibrations. This can be related to variations in molecular data (small subunit, long subunit and internal transcribed spacer sequences), which show the presence of several genotypes and the occurrence of pseudo‐cryptic speciation within this species. Copyright © 2012 John Wiley & Sons, Ltd.

Protoceratium reticulatum (Dinophyceae) in the austral Southwestern Atlantic and the first report on YTX-production in shelf waters of Argentina

“…fundyense/A. catenella species complex (Supplementary material Table 2, Bolch and de Salas, 2007;Daugbjerg et al, 2000;Ellegaard et al, 2003;Herrera-Sepú lveda et al, 2013;Higman et al, 2001;Kim et al, 2006;Kim and Kim, 2007;Mertens et al, 2012;Orr et al, 2011;Riccardi et al, 2006;Ruiz Sebastiá n and O'Ryan, 2001;Scorzetti et al, 2009;Walsh et al, 1998). A sequence of Prorocentrum minimum was included as outgroup.…”

Salinity changes and anoxia resulting from enhanced run-off during the late Permian global warming and mass extinction event

“…The choice of processes was limited due to compaction of the acritarchs. If more than three processes were available for measurement, a focal plane was chosen that showed the most and best preserved processes, from which we measured the three longest, following the methodology of Mertens et al (2012). The aim was to measure 20-30 specimens per sample, but acritarch concentrations were low during the biotic crisis interval, and therefore five samples had lower counts (indicated in Fig.…”

“…The body size of some dinocysts has been found to vary with temperature and salinity (e.g. Ellegaard et al, 2002;Mertens et al, 2012); however, the relationship has not been well studied. Possibly low-oxygen or low-salinity conditions or increased nutrient availability influenced acritarch body size in this interval.…”

“…Mertens et al, 2009Mertens et al, , 2012 but this relationship is not always evident (e.g. Ellegaard et al, 2002).…”

“…Of these, the organic-walled cysts of dinoflagellates have proven especially useful in palaeoenvironmental studies (e.g. Ellegaard, 2000;Mertens et al, 2009Mertens et al, , 2012Mudie et al, 2001Mudie et al, , 2002Sluijs and Brinkhuis, 2009;de Vernal et al, 2000). While dinocysts are absent or sparse in Palaeozoic deposits, acritarchs are commonly recorded (e.g.…”