Effects of cyst resuspension on germination and seeding of two bloom-forming dinoflagellates in the Baltic Sea

Abstract

The implications of cyst resuspension on germination and subsequent seeding of the 2 spring-bloom dinoflagellates Scrippsiella hangoei (Schiller) Larsen and Peridiniella catenata (Levender) Balech from the Baltic Sea were investigated in a field study and laboratory experiments. Sedimentation of resuspended cysts was monitored by an automated sediment trap in 2 consecutive winters prior to and throughout the germination period off the SW coast of Finland. The effects of increased irradiances and water motion on germination and germling survival were tested by incubating cysts at different light levels and in turbulent water. Cyst fluxes of both species were low during the calm and cold winter of 1998/1999. In 1999/2000, heavy storms caused strong resuspension of S. hangoei cysts. Light significantly increased the germination frequency of S. hangoei cysts and supported germling survival and cell division. In P. catenata, the percentage of excystment was not significantly influenced by light and germination was successfully completed in both darkness and light. Subsequent growth of the species, however, required light, although maximum cell numbers were encountered at an irradiance as low as 10 µmol m -2 s -1. Small-scale turbulence reduced the germination frequency of S. hangoei but did not affect excystment in P. catenata. No negative effects on subsequent growth were detected. The favourable effects of light on germination and germling survival of S. hangoei emphasize that resuspension would be advantageous for the bloom initiation of this species. Cyst resuspension seems to be less important in P. catenata population dynamics, since germination can be successfully completed in darkness and the amount of cysts transported to the water surface is insignificant even with strong turbulent mixing. It is concluded that cyst resuspension may be advantageous for dinoflagellate bloom initiation, depending on its extent and timing and the specific germination requirements of the respective organism.KEY WORDS: Cysts · Dinoflagellates · Germination · Peridiniella · Resuspension · Scrippsiella turbulence Resale or republication not permitted without written consent of the publisher

Impacts of nutrient enrichment and sediment on phytoplankton community structure in the northern Baltic Sea

“…Recruitment from sediment has been observed among various algal groups, including cyanobacteria (Pettersson et al, 1993;Olli et al, 2005), dinoflagellates (Hansson, 1996;Kremp, 2001;McQuoid, 2005) cryptophytes (Salonen et al, 1984;Hansson, 1996), chrysophytes (Sandgren, 1983), diatoms (McQuoid & Godhe, 2004;McQuoid, 2005), and euglenophytes (Olli et al, 1996). Recruitment from resting stages usually occurs in response to an external stimulus, such as a change in temperature, light conditions, nutrient or oxygen concentrations, salinity or grazer abundance (Fryxell, 1983;Hansson, 1996;McQuoid, 2005;Olli et al 2005).…”

“…These resting stages form a seed bank of organisms that may be able to respond quickly to changes in the environment (Padisá k, 1992;Hansson, 1996;McQuoid, 2005). Migration from the sediment surface via either recruitment or growth can play a significant role in plankton dynamics and bloom formation (Hansson, 1996;Kremp, 2001;McQuoid & Godhe, 2004).…”

Influence of salinity on seasonal germination of resting stages and composition of microplankton on the Swedish west coast

“…Germination of resting stages and successful growth of newly germinated vegetative cells can play a significant role in coastal microplankton dynamics and bloom formation (Ishikawa & Taniguchi 1997, Itakura et al 1997, Kremp 2001. For microplankton in coastal areas, some sudden increases in population cannot be explained by vegetative division alone.…”

“…Binder & Anderson 1987, Kremp 2001. For some dinoflagellates, a required maturation period may also restrict germination to a particular season (Anderson & Keafer 1987, Nuzzo & Montresor 1999, Kremp & Anderson 2000.…”

Monitoring of a Potential Harmful Algal Species in the Berre Lagoon by Automated In Situ Flow Cytometry

“…However, wind and storms have been considered as factors of resuspension and dispersal leading to the increase of harmful algal blooms (Anderson 1989 ;Kremp 2001 ). Resuspension and dispersal of a high concentrated inoculum of resistant cysts could indeed conduct to massive and sudden proliferation if environmental conditions favor their germination.…”