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Responses of phyto- and zooplankton communities to Prymnesium polylepis (Prymnesiales) bloom in the Baltic Sea.

Gorokhova E, Hajdu S, Larsson U - PLoS ONE (2014)

Bottom Line: The only negative response, possibly associated with P. polylepis occurrence, was significantly lower abundance of dinoflagellates both during and after the bloom in 2008.Moreover, contrary to the expected negative effects, there were significantly higher total phytoplankton abundance as well as significantly higher winter abundance and winter-spring RNA:DNA ratio in dominant zooplankton species in 2008, indicating that P. polylepis bloom coincided with favourable feeding conditions for zooplankton.Thus, primary consumers, and consequently also zooplanktivores (e.g., larval fish and mysids), may benefit from haptophyte blooms, particularly in winter, when phytoplankton is scarce.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden; Department of Applied Environmental Science, Stockholm University, Stockholm, Sweden.

ABSTRACT
A large bloom of Prymnesium polylepis occurred in the Baltic Sea during the winter 2007-spring 2008. Based on numerous reports of strong allelopathic effects on phytoplankton exerted by P. polylepis and its toxicity to grazers, we hypothesized that during this period negative correlations will be observed between P. polylepis and (1) main phytoplankton groups contributing to the spring bloom (i.e., diatoms and dinoflagellates), and (2) zooplankton growth and abundance. To test these hypotheses, we analyzed inter-annual variability in phytoplankton and zooplankton dynamics as well as growth indices (RNA:DNA ratio) in dominant zooplankton in relation to the Prymnesium abundance and biomass. Contrary to the hypothesized relationships, no measurable negative responses to P. polylepis were observed for either the total phytoplankton stocks or the zooplankton community. The only negative response, possibly associated with P. polylepis occurrence, was significantly lower abundance of dinoflagellates both during and after the bloom in 2008. Moreover, contrary to the expected negative effects, there were significantly higher total phytoplankton abundance as well as significantly higher winter abundance and winter-spring RNA:DNA ratio in dominant zooplankton species in 2008, indicating that P. polylepis bloom coincided with favourable feeding conditions for zooplankton. Thus, primary consumers, and consequently also zooplanktivores (e.g., larval fish and mysids), may benefit from haptophyte blooms, particularly in winter, when phytoplankton is scarce.

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Dynamics of total phytoplankton (TPhyto) and Prymnesium polylepis (biovolume, left axis), total zooplankton (TZoo) and copepods (biomass; right axis) during 2007 and 2008 at the monitoring stations in the Baltic proper.Note that in September 2007, TZoo value at stn BY15 is outside the axis limits.
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pone-0112985-g002: Dynamics of total phytoplankton (TPhyto) and Prymnesium polylepis (biovolume, left axis), total zooplankton (TZoo) and copepods (biomass; right axis) during 2007 and 2008 at the monitoring stations in the Baltic proper.Note that in September 2007, TZoo value at stn BY15 is outside the axis limits.

Mentions: In summer 2007, P. polylepis was found at all open sea stations, increasing during autumn and reaching 0.3×103 to 73×103 cells L−1 in November–December. At this time, P. polylepis contributed up to 70–80% to the total phytoplankton biovolume, with particularly high values at stns BY31 and B1. Moreover, the alternate stage of P. polylepis, which has not hitherto been found in phytoplankton samples, dominated Prymnesiales assemblages during winter (Figure S1). In spring 2008, P. polylepis became very abundant in the whole Baltic Sea proper (Figure 2). During this time, Prymnesiales 6–10 µm also contributed substantially in all study areas (Figure S1). On an annual basis, P. polylepis contributed up to 40% of the total phytoplankton biovolume in the north (stns BY31 and B1), ∼30% at the central basin (stn BY15), and up to −8% in the south (stns BY2 and BY5). At the northern stations, P. polylepis occurred during the whole year, except for a short period in summer, when the dinoflagellate Heterocapsa triquetra (Ehrenberg) Stein dominated, whereas at the central and southern stations it was found only in low numbers during the second half of the year.


Responses of phyto- and zooplankton communities to Prymnesium polylepis (Prymnesiales) bloom in the Baltic Sea.

Gorokhova E, Hajdu S, Larsson U - PLoS ONE (2014)

Dynamics of total phytoplankton (TPhyto) and Prymnesium polylepis (biovolume, left axis), total zooplankton (TZoo) and copepods (biomass; right axis) during 2007 and 2008 at the monitoring stations in the Baltic proper.Note that in September 2007, TZoo value at stn BY15 is outside the axis limits.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231118&req=5

pone-0112985-g002: Dynamics of total phytoplankton (TPhyto) and Prymnesium polylepis (biovolume, left axis), total zooplankton (TZoo) and copepods (biomass; right axis) during 2007 and 2008 at the monitoring stations in the Baltic proper.Note that in September 2007, TZoo value at stn BY15 is outside the axis limits.
Mentions: In summer 2007, P. polylepis was found at all open sea stations, increasing during autumn and reaching 0.3×103 to 73×103 cells L−1 in November–December. At this time, P. polylepis contributed up to 70–80% to the total phytoplankton biovolume, with particularly high values at stns BY31 and B1. Moreover, the alternate stage of P. polylepis, which has not hitherto been found in phytoplankton samples, dominated Prymnesiales assemblages during winter (Figure S1). In spring 2008, P. polylepis became very abundant in the whole Baltic Sea proper (Figure 2). During this time, Prymnesiales 6–10 µm also contributed substantially in all study areas (Figure S1). On an annual basis, P. polylepis contributed up to 40% of the total phytoplankton biovolume in the north (stns BY31 and B1), ∼30% at the central basin (stn BY15), and up to −8% in the south (stns BY2 and BY5). At the northern stations, P. polylepis occurred during the whole year, except for a short period in summer, when the dinoflagellate Heterocapsa triquetra (Ehrenberg) Stein dominated, whereas at the central and southern stations it was found only in low numbers during the second half of the year.

Bottom Line: The only negative response, possibly associated with P. polylepis occurrence, was significantly lower abundance of dinoflagellates both during and after the bloom in 2008.Moreover, contrary to the expected negative effects, there were significantly higher total phytoplankton abundance as well as significantly higher winter abundance and winter-spring RNA:DNA ratio in dominant zooplankton species in 2008, indicating that P. polylepis bloom coincided with favourable feeding conditions for zooplankton.Thus, primary consumers, and consequently also zooplanktivores (e.g., larval fish and mysids), may benefit from haptophyte blooms, particularly in winter, when phytoplankton is scarce.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden; Department of Applied Environmental Science, Stockholm University, Stockholm, Sweden.

ABSTRACT
A large bloom of Prymnesium polylepis occurred in the Baltic Sea during the winter 2007-spring 2008. Based on numerous reports of strong allelopathic effects on phytoplankton exerted by P. polylepis and its toxicity to grazers, we hypothesized that during this period negative correlations will be observed between P. polylepis and (1) main phytoplankton groups contributing to the spring bloom (i.e., diatoms and dinoflagellates), and (2) zooplankton growth and abundance. To test these hypotheses, we analyzed inter-annual variability in phytoplankton and zooplankton dynamics as well as growth indices (RNA:DNA ratio) in dominant zooplankton in relation to the Prymnesium abundance and biomass. Contrary to the hypothesized relationships, no measurable negative responses to P. polylepis were observed for either the total phytoplankton stocks or the zooplankton community. The only negative response, possibly associated with P. polylepis occurrence, was significantly lower abundance of dinoflagellates both during and after the bloom in 2008. Moreover, contrary to the expected negative effects, there were significantly higher total phytoplankton abundance as well as significantly higher winter abundance and winter-spring RNA:DNA ratio in dominant zooplankton species in 2008, indicating that P. polylepis bloom coincided with favourable feeding conditions for zooplankton. Thus, primary consumers, and consequently also zooplanktivores (e.g., larval fish and mysids), may benefit from haptophyte blooms, particularly in winter, when phytoplankton is scarce.

Show MeSH
Related in: MedlinePlus