Peridiniella Catenata Research Articles

Dynamics of cold-water dinoflagellates in the northern Baltic Sea based on 18S rRNA gene metabarcoding

Cold-water dinoflagellates contribute significantly to spring blooms in temperate coastal waters. In the northern Baltic Sea, Peridiniella catenata, Apocalathium malmogiense, Gymnodinium corollarium, and Biecheleria baltica predominate the dinoflagellate spring blooms. Spring dynamics of cold-water dinoflagellates have been previously studied using cyst sedimentation data. Here, we utilize time-series data based on amplicons of the V4 region of the 18S rRNA gene spanning from autumn 2012 to spring 2013 and describe dynamics and habitat preferences of the relatively most abundant dinoflagellates in the northern Baltic Sea. Our results indicate that these species preferred either sea ice, under-ice water, or deeper water columns during the ice-covered season and that they shifted in temporal dominance during our sampling period.

Patterns of vertical cyst distribution and survival in 100-year-old sediment archives of three spring dinoflagellate species from the Northern Baltic Sea

The history of expansion of bloom-forming cold water dinoflagellates in the Northern Baltic Sea was studied using 100-year-old sediment archives of their resting cysts. Vertical cyst distributions of Biecheleria baltica and Apocalathium malmogiense, two dinoflagellates indistinguishable by light microscopy and not recognized as distinct species in monitoring, and chain-forming Peridiniella catenata were analysed in Pb210 and Cs137 dated layers of a sediment core from deep, hypoxic accumulation bottoms of the Gulf of Finland. Cyst profiles showed that B. baltica and A. malmogiense were already present in the Baltic spring phytoplankton community at the beginning of the 20th century. This confirms that B. baltica, which was only recognized in the late 1980s, is a native species in the area. A drastic increase in B. baltica cyst concentrations in the 1930s to 1960s coincided with the acceleration of anthropogenic eutrophication. Large cyst deposits accumulated over several decades in the sediment which, by the 1980s, amounted to the seed stock necessary to inoculate dominant blooms. In the cyst records A. malmogiense always contributed a minor fraction of the two species. P. catenata had a relatively short cyst record in Gulf of Finland sediments despite demonstrated long-term presence in the plankton, which emphasizes that cyst-based historic surveys are not suitable for all cyst-forming dinoflagellates. This was corroborated by correspondence analyses of long-term plankton and cyst records which validated the trends from the sediment archive for B. baltica and A. malmogiense, but failed to do so for P. catenata. Germination experiments with 100-year-old cysts revealed a remarkable long-term survival capacity of A. malmogiense, making this species a suitable model for resurrection studies testing adaptation in heavily impacted systems such as the Baltic Sea.

High-resolution dynamics of the spring bloom in the Gulf of Finland of the Baltic Sea

During the period from March to the end of May in 2009 and 2010, intensive measurements and sampling were undertaken in the Gulf of Finland. The compiled results indicate a high variability of the phytoplankton distribution both temporally and spatially. The spring bloom dynamics and heterogeneity was influenced by physical forcing, such as prevailing circulation in the surface layer and the development of stratification, including the upward and downward movement of the seasonal thermocline. The estimated ratio of nitrogen to phosphorus consumption during the growth phase of the spring bloom was close to the Redfield ratio during both springs. The maximum phytoplankton carbon biomass was observed after the depletion of inorganic nitrogen from the surface layer, which coincides with the transition in the community dominance from diatoms to dinoflagellates. Diatoms exhibited a short, well-defined period of high biomass, and we argue that measurements with low temporal resolution can overlook this period of diatom dominance in the Gulf of Finland. The observed dominance of dinoflagellates (Peridiniella catenata and the Scrippsiella/Biecheleria complex) and the ciliate Myrionecta rubra might have a substantial biogeochemical impact because these species increase the retention time of newly produced material in the nutrient-limited surface layer in late spring.

Spring phytoplankton communities shaped by interannual weather variability and dispersal limitation: Mechanisms of climate change effects on key coastal primary producers

Spring bloom composition in the Baltic Sea, a partially ice‐covered brackish coastal waterbody, is shaped by winter‐spring weather conditions affecting the relative dominance of diatoms and a heterogeneous assemblage of cold‐water dinoflagellates, dominated by the chain‐forming Peridiniella catenata and a complex of at least three medium‐sized, single‐celled species: Biecheleria baltica, Gymnodinium corollarium, and Scrippsiella hangoei. During the last decades, the bloom community has dramatically changed in several basins. We analyze here a 30 yr time series of quantitative phytoplankton data, as predicted by hindcast modeled ice thickness and storminess for three distinct Baltic Sea localities, to verify climate‐driven mechanisms affecting the spring bloom composition. Thick (> 30 cm) and long‐lasting ice cover favored diatom‐dominated spring blooms, and mild winters, with storms and thin ice cover (10 to 20 cm), supported blooms of the B. baltica complex. Dispersal limitation plays an important role in the spatial extent of blooms of the B. baltica complex, caused by intricate interplay of local hydrodynamics and the dinoflagellate life cycle. Proportion peaks of key phytoplankton groups have shifted about 10 d earlier in the northwestern Baltic Sea (P. catenata and diatoms) and in the Gulf of Riga (P. catenata). The significant weather effects imply future shifts in spring bloom composition and consequent biogeochemical cycles, driven by the predicted changes in winter storminess and decrease in ice cover extent and duration in climate change models.

Abundance and distribution of vernal bloom dinoflagellate cysts in the Gulf of Finland and Gulf of Riga (the Baltic Sea)

In the northern Baltic Sea, brackish water dinoflagellates Peridiniella catenata, Woloszynskia spp. and Scrippsiella hangoei form a major part of the spring bloom biomass, comparable to, or even exceeding the biomass of diatoms. The life cycle of these dinoflagellates involves a relatively short period of vegetative growth in early spring (2–3 months), followed by encystment during the first part of May, and a resting period in the form of benthic cysts. The bloom intensity of the Woloszynskia/Scrippsiella complex in the Baltic Sea is spatially variable, with peak abundances in the central and eastern Gulf of Finland, while the species are rare in the Gulf of Riga. During a field survey in late May 2004, we investigated the abundance and distribution of benthic cysts of P. catenata and Woloszynskia spp. in surface (5 cm) sediments around the Estonian coast. The broad distribution patterns of benthic cysts reflected the overall knowledge of basin-wide planktonic phase distribution of the species. On a finer scale, sediment properties (percent of clay, organic matter content) demarked the accumulation regions of the cysts. Woloszynskia cyst abundances in the surface 5 cm sediment were up to 3.2×106 cysts cm−2 and Peridiniella cyst abundances were approximately an order of magnitude less, up to 0.3×106 cysts cm−2.

Vertical distribution and cyst production of Peridiniella catenata (Dinophyceae) during a spring bloom in the Baltic Sea

Vertical distribution and cyst production of the chain-forming, spring dinoflagellate Peridiniella catenata were studied throughout the spring season of 2000 in the coastal Gulf of Finland. Numbers of cells were monitored in the water column, and cyst sedimentation was recorded using multiple sediment traps moored at three discrete depths. At the onset of the spring bloom, most of the population was situated in the euphotic zone. When the bloom progressed, the population was more evenly dispersed throughout the water column. Coinciding with the decline of the spring bloom, after nitrogen depletion, a general reduction of cell size of P. catenata and a break-up of chains were observed. Resting cysts started to appear shortly after the peak of the bloom, in sedimentation traps moored at 30 and 40 m depth. Cysts were only retrieved from the uppermost sediment trap on three of the six sampling occasions, constituting only a small proportion of all cysts produced by P. catenata during spring. Our results suggest that cyst production of this vertically migrating organism takes place to a large extent in deep water layers and emphasizes the necessity of whole water column monitoring in studies aiming to understand in situ life-cycle transformations of vertically migrating dinoflagellates.

Phylogeny of some of the major genera of dinoflagellates based on ultrastructure and partial LSU rDNA sequence data, including the erection of three new genera of unarmoured dinoflagellates

Evidence from partial large-subunit (LSU) rDNA sequencing has been combined with ultrastructure, including details of the flagellar apparatus, in a number of phototrophic dinoflagellates, with the aim of trying to solve some of the most pressing taxonomic problems and to contribute to an improved understanding of the phylogeny within the group. Special attention has been paid to the unarmoured (naked) genera, many of which were described during the 1800s or early 1900s and whose taxonomy is artificial and misleading. This is particularly unsatisfactory because many of the species cause extensive plankton blooms, fish kills and other harmful events. Our studies have indicated that the path of the so-called apical groove (acrobase) is of particular importance for the taxonomy of the unarmoured genera of dinoflagellates. Features presently used to characterize many of the genera, such as the relative size of the epicone and hypocone, are misleading. Our data have resulted in the splitting of the large genus Gymnodinium into four genera. The fish-killing species are confined to two genera, Karenia G. Hansen & Moestrup gen. nov. and Karlodinium J. Larsen gen. nov. The paralytic shellfish poisoning-producing species Gymnodinium catenatum is retained within Gymnodinium, together with a number of harmless species. The fourth genus, Akashiwo G. Hansen & Moestrup gen. nov., presently comprises only the large nontoxic species previously known as Gymnodinium sanguineum. The genus Gyrodinium is redefined. The genus Amphidinium is artificial, but more data are needed before redescription of the genus can be made with any confidence. Within the armoured dinoflagellates, LSU and previously published small-subunit rDNA data show the Gonyaulacales to be a natural group. Peridiniella catenata, sometimes included in the Gonyaulacales based on gross morphology, falls outside this order both genetically and ultrastructurally. Based on the DNA data, the genus Peridinium appears to be artificial. Ultrastructure as well as gene sequences confirm that the genus Heterocapsa is unusual, since it includes both apparently unarmoured species (but with very thin plates) and armoured species.

Morphology and germination pattern of the resting cyst of Peridiniella catenata (Dinophyceae) from the Baltic Sea

The resting cyst of the cold-water dinoflagellate Peridiniella catenata is described from sediments collected off the southwest coast of Finland, Baltic Sea. The timing of germination was determined for this cyst type, and the dynamics of benthic cysts and planktonic cells were investigated during the seasonal cycle. The discoid, colourless, and thin-walled cysts germinated after a dormancy period of six months, and the emerging vegetative cells were identified as P. catenata. Synchronized excystment occurred in midwinter at 2°C. The decrease of cyst abundance in the surface sediments coincided with the appearance of vegetative cells in the water column. The decay of the vegetative population was followed by a massive input of cysts into the sediments. It is concluded that cyst formation, dormancy interval, and the timing of germination play a role in regulating the seasonal appearance of P. catenata in the water column.

Diel vertical migration of phytoplankton and heterotrophic flagellates in the Gulf of Riga

Vertical distribution of a phototrophic ciliate ( Mesodinium rubrum), autotrophic dinoflagellates ( Peridiniella catenata, Heterocapsa rotundata, Dinophysis acuminata), a cryptomonad ( Teleaulax sp.), a filamentous cyanobacterium ( Aphanizomenon flos-aquae), a non-motile chlorophyte ( Monoraphidium sp.) and two heterotrophic dinoflagellates were studied during two diel periods in spring (May 1–2 and 27–28, 1995) and summer (June 26–27 and July 6–7, 1994) in the southern part of the Gulf of Riga, the Baltic Sea. The two seasons, corresponding to the vernal bloom and summer stage, differed considerably with respect to phytoplankton community, hydrography and vertical distribution of the species. In spring the cells stayed in the upper mixed layer above a strong thermocline at 12–15 m depth, and changes in the vertical distribution were related to surface avoidance in the middle of the day. By using correspondence analysis, the vertical distribution of all the motile species were shown to differ significantly from the non-motile Monoraphidium, but not from each other. The vertical migration was reflected in a higher variability in the depth distribution patterns of the motile species, compared to Monoraphidium. In summer 1994, Aphanizomenon, Dinophysis and Teleaulax showed similar depth distribution patterns during the first period, but different from Mesodinium and the heterotrophic dinoflagellates, while during the second period all the autotrophic species had a species specific depth distribution pattern. Me. rubrum revealed a considerably different depth distribution between the two seasons, characterised by surface accumulation in spring and relatively uniform depth distribution over the whole sampling range (0–30 m) in summer. The results demonstrate different vertical niche separation strategies between species.

Seasonal stages of phytoplankton community structure and sinking loss in the Gulf of Riga

In this paper, we present the biomass, species composition and sinking losses of phytoplankton and heterotrophic flagellates obtained during three seasonal stages (May 1995; June–July 1994; August 1993) from the Gulf of Riga — a eutrophied, semi-enclosed area in the Baltic Sea. The Gulf was characterised by intensive dinoflagellate (mainly Peridiniella catenata) dominated spring bloom (2700–7600 μg l −1 wet weight) while the diatom Thalassiosira baltica contributed most (80–90%) to the settling phytoplankton biomass (up to 6.5 g m −2 day −1). The mineral nutrients were abundant during the bloom and it is suggested that the differential sedimentation of species was caused by physical factors (thermal stratification of the water column). The phytoplankton biomass in summer (780–2600 μg l −1) was dominated by high abundance of filamentous cyanobacterium Aphanizomenon flos-aquae, autotrophic nanoflagellates and picoplankton. The primary vertical flux of phytoplankton (<1 g m −2 day −1) was mainly due to non-motile species and aggregate-bound picoplankton and A. flos-aquae. Below the pycnocline, resuspended dormant diatom populations caused a significant (up to 1 g m −2 day −1) secondary flux. Large heterotrophic dinoflagellates ( Gyrodinium/Gymnodinium) were abundant (up to 500 μg l −1) in the middle layers and associated to ammonium regeneration. The early autumn stage was a post cyanobacterial bloom situation with relatively low phytoplankton abundance (330–860 μg l −1) dominated by A. flos-aquae and nanoflagellates. Also, the sedimentation of phytoplankton was lowest (up to 340 mg m −2 day −1). Our results indicate high seasonal differences in the phytoplankton community structure and sedimentation. However, the high within-season temporal variability overrules the variability between different areas of the southern part of the Gulf.

An Ice-Bound Planktonic Dinoflagellate Peridiniella catenata (Levander) Balech: Morphology, Ecology and Distribution

On the basis of original plankton and sea-ice samples from the Siberian seas the morphology of the theca in the dinoflagellate Peridiniella catenata has been studied using both light and scanning electron microscopy. All available data on the ecology and geographical distribution of the species have been analysed, its range being presented. It is concluded that P. catenata is one of a few Arctic-boreal dinoflagellates, and cold-water, euryhaline, brackish-water-marine, ice-bound planktonic species. It is the only dinoflagellate hitherto known which is able to develop in abundance in the sea ice. Considering the thecal morphology with emphasis on the sulcal plates, the systematic position of P. catenata, along with the two other species, P. sphaeroidea and P. danica, in the same genus seems to be natural.

Light and electron microscopical observations on Peridiniella catenata (Dinophyceae)

The coldwater dinoflagellate Peridiniella catenata has been examined by light and electron microscopy. The fine-structure resembles that of other dinoflagellates with regard to the dinokaryon, the chloroplast enveloped by three membranes, and the pusule. The flagellar apparatus also resembles that of most other dinoflagellates. The main difference is a missing or reduced striated root connective between the longitudinal microtubular flagellar root and the transverse striated flagellar root. The amphiesma includes a scale-like layer on the outside of the plasmalemma. Another unusual feature is the presence of two distinct size classes of trichocysts, measuring c. 0.2×1 μm and c. 0.7×4 μm, respectively. In their detailed construction they resemble those of other dinoflagellate trichocysts. Peridiniella catenata differs from other gonyaulacoid dinoflagellates in the presence of chloroplasts with single-stalked pyrenoids and in details of the pusular complex. The presence of two size categories of trichocysts and the outer scale-like layer have not been observed in other gonyaulacoid dinoflagellates, indicating that P. catenata is not closely related to these dinoflagellates. However, the presence of two striated collar connectives in P. catenata, a feature hitherto observed only in gonyaulacoids, implies affinity to this group.

Light and electron microscopical observations on Peridiniella catenata (Dinophyceae)

The coldwater dinoflagellate Peridiniella catenata has been examined by light and electron microscopy. The fine-structure resembles that of other dinoflagellates with regard to the dinokaryon, the chloroplast enveloped by three membranes, and the pusule. The flagellar apparatus also resembles that of most other dinoflagellates. The main difference is a missing or reduced striated root connective between the longitudinal microtubular flagellar root and the transverse striated flagellar root. The amphiesma includes a scale-like layer on the outside of the plasmalemma. Another unusual feature is the presence of two distinct size classes of trichocysts, measuring c. 0.2×1 μm and c. 0.7×4 μm, respectively. In their detailed construction they resemble those of other dinoflagellate trichocysts. Peridiniella catenata differs from other gonyaulacoid dinoflagellates in the presence of chloroplasts with single-stalked pyrenoids and in details of the pusular complex. The presence of two size categories of trichocysts and the outer scale-like layer have not been observed in other gonyaulacoid dinoflagellates, indicating that P. catenata is not closely related to these dinoflagellates. However, the presence of two striated collar connectives in P. catenata, a feature hitherto observed only in gonyaulacoids, implies affinity to this group.

Influence of sea ice on the composition of the spring phytoplankton bloom in the northern Baltic Sea

During the late winter and spring of 1994, the influence of sea ice on phytoplankton succession in the water was studied at a coastal station in the northern Baltic Sea. Ice cores were taken together with water samples from the underlying water and analysed for algal composition, chlorophyll a and nutrients. Sediment traps were placed under the ice and near the bottom, and the sedimented material was analysed for algal composition. The highest concentration of ice algae (4.1 mmol C m−2) was found shortly before ice break-up in the middle of April, coincidental with the onset of an under-ice phytoplankton bloom. The ice algae were dominated by the diatoms Chaetoceros wighamii Brightwell, Melosira arctica (Ehrenberg) Dickie and Nitzschia frigida Grunow. Under the ice the diatom Achnanthes taeniata Grunow and the dinoflagellate Peridiniella catenata (Levander) Balech were dominant. Calculations of sinking rates and residence times of the dominant ice algal species in the photic water column indicated that only one ice algal species (Chaetoceros wighamii) had a seeding effect on the water column: this diatom dominated the spring phytoplankton bloom in the water together with Achnanthes taeniata and Peridiniella catenata.

Biodiversity and biogeography of planktonic dinoflagellates in the Arctic Ocean

Data on the species diversity and distribution of arctic planktonic dinoflagellates was obtained from a large number of samples collected during sixteen expeditions and from the relevant literature. Based on an analysis of the ranges of about 250 dinoflagellate species recorded, only four Arctic-boreal species, Alexandrium ostenfeldii, Amylax triacantha, Ceratium arcticum and Dinophysis norvegica, and four provisionally bipolar species, Dinophysis arctica, Protoperidinium islandicum, P. saltans and P. thulesense, were recognised. No purely Arctic species or genera endemic to the Arctic were discovered and this may be considered evidence for the unity of the Arctic-boreal biogeographical zone. An increased number of species were found in the areas influenced directly by the warm Atlantic or Pacific currents, such as the Norwegian, Barents and Chukchi Seas, mainly due to the invasion of tropical-boreal and Antarctic-tropical-boreal species. These forms tend to penetrate into the Arctic along the western coasts of the continents. Only two species, Peridiniella catenata and Gymnodinium cf. punctatum, are reliably associated with sea ice. Analysis by the multivariate techniques, Twinspan and Decorana, revealed two main clusters; one, influenced by the warmer waters of the Atlantic and Pacific currents, and the other consisting of the cold water regions.

Fate of a phytoplankton spring bloom: sedimentation and carbon flow in the planktonic food web in the northern Baltic

During the spring bloom in 1988, the dynamics of planktonic carbon flow were studied weekly in the euphotic layer in the northern Baltic. The spring bloom developed after the formation of a s l~gh t vertical salinity gradient near the surface at the end of April, and a peak in phytoplankton primary productivity and biomass (dominated by the dinoflagellate Peridiniella catenata) was reached about 1 wk later. The biomass of all heterotrophic compartments, especially that of bactena and copepods, increased strongly durlng the peak and declining phases of the algal bloom, showing that their success was closely linked with the bloom. During the whole bloonl period, the integral pnmary production (I4C incorporation) was 45.5 g C m-', and 'new' (NO<-N-based) production contributed about 80% of this value. The rotifers-copepods grazing chain and the bacteria-heterotrophic nanoflagellates-ciliates 'microbial loop' consumed directly about the same amount (3.5 g C m-') of phytoplankton carbon. Algae accounted for 64% of the total carbon consumption of zooplankton. Sedimentation corresponded to 72% of the primary production. The sum of algal biomass increase and loss factors (exudation, grazing and sedimentation) was 94% of the integral primary production, which supports our conclusion that there is a strong imbalance between primary and secondary production in the vernal planktonic food web off the SW coast of Finland.