Modem organic-walled dinoflagellate cysts in arctic marine environments and their (paleo-) environmental significance

Hydrological changes in the White Sea during the historical period inferred from analysis of dinocysts

“…tribution of these species and their ecological tolerance [12] as well as with results of our previous studies in the White Sea (table, [9]). The autotrophic community consisting of five species is dominated by Operculodinium centrocarpum , which prevails also in Recent sediments of the White Sea [9].…”

“…Such a situation was also characteristic of the last 250 years. This is evident from practically complete lack of freshwater green algae in sediments, which reflect river runoff in the Arctic shelf seas [12]. The present-day hydrological situation in study areas is determined by the distribution of seasonally stratified White Sea waters with a low content of suspended matter [7,14].…”

Analysis of the hydrographic conditions and cyst beds in the San Jorge Gulf, Argentina, that favor dinoflagellate population development including toxigenic species and their toxins

“…However, this species was more abundant in the motile stage of station C45 (82.0 × 10 3 cells NT − 1 , see Table 4) and no clear relation was observed with the cyst abundance (0.9 × 10 3 cysts g −1 ). It is necessary to consider that the water-column analysis of planktonic communities are only temporal snapshots whereas sediment assemblages reflect an average of cysts produced by surface communities over time (Matthiessen et al, 2005). Other factors, such as granulometry and accumulation rate of bottom sediments, need to be taken into account.…”

“…Cysts enter in quiescence and when environmental conditions are appropriate, excystment is triggered (Warns et al, 2012). In laboratory experiments germination can be triggered by temperature, light availability, oxygen concentration and endogenous rhythms (Matthiessen et al, 2005 and literature therein). About 200 living marine dinoflagellates, including a number of harmful species, are known to produce organic-walled dinoflagellate cysts ("dinocysts") which are even preserved in conditions in which calcareous (coccoliths, foraminiferal tests) and siliceous (diatom frustules, radiolarian skeletons) microplankton remains are prone to dissolution (De Vernal and Marret, 2007).…”

Dinoflagellates

“…Matthiessen et al, 2005). After a mandatory dormancy period 107 of variable length, excystment is triggered by different environmental factors.…”