Ceratium Fusus Research Articles

Photoenhancement of bioluminescence capacity in natural and laboratory populations of the autotrophic dinoflagellate Ceratium fusus (Ehrenb.) Dujardin

Cultures of Ceratium fusus were grown at seven light intensities (5 to 400 μmol photons m−2 s−1 as photosynthetically active radiation (PAR)) in the laboratory. Measurements of bioluminescence capacity (BCAP), division rate, and cell size were made at each intensity and compared to similar data from natural populations. In cultures, BCAP increased by a factor of 5–10 with increasing light. Division rates ranged from 0 d−1 (5 μmol photons m−2 s−1) to about 0.16 d−1 (100 μmol photons m−2 s−1). In these cultures, BCAP was highly correlated with both the log of light (r2 = 0.89) and division rate (r2 = 0.69), suggesting that BCAP may be of use as an in‐situ indicator of division rate. In both cultures and natural populations, BCAP was poorly correlated with cell size (r2 ≈ 0.3 and r2 ≈ 0.1 respectively). For populations from the Gulf of Maine ( ∼42°N, 69° W) and the Marine light‐Mixed Layers (MLML) site (∼59°N, 21° W), division rates in the mixed‐layer could only be determined with statistical certainty at the Gulf of Maine station (0.04 to 0.17 d−1). At the MLML site, BCAP in C. fusus was greater in the mixed‐layer in May and below the mixed‐layer in August. The August result is opposite to what culture photoenhancement studies would predict if light was the factor controlling BCAP.

Bioluminescent organisms and bioluminescence measurements in the North Atlantic Ocean near latitude 59.5°N, longitude 21°W

We investigated mixed‐layer bioluminescence from early April to late September (in April 1989, May 1991, July 1983 and 1990, August 1991, September 1988 and 1989) at stations near the Marine‐Light ‐ Mixed Layers (MLML) bio‐optical moorings site. Volume‐specific bioluminescence potential (BPOT, photons per unit volume) from epipelagic organisms was estimated directly with a pump‐through bioluminescence photometer (BP) in 1983, 1988, and 1991. For all cruises, BPOT was also estimated by summing for a volume of seawater, the measurements of each species′ total stimulable bioluminescence multiplied by each species′ numerical abundance in the volume. The abundance data were taken from bottle casts, net tows, and BP effluent nets. After the onset of the spring bloom, from May through September, mixed layer BPOT was fairly constant, ∼1–4×1014 photons m−3. On one early April cruise (1989) before the spring bloom, BPOT was two orders of magnitude lower. Heterotrophic dinoflagellates in the genus Protoperidinium generally produced most (90% or more) of the mixed layer BPOT in the spring, summer, and fall. On one cruise in September (1988), the autotrophic dinoflagellate Ceratium fusus produced the bulk of the mixed layer BPOT (more than about 4×1014 photons m−3). Other autotrophic dinoflagellates in the genus Gonyaulax and mesozooplankton produced a minor part of BPOT at most stations. The relative contribution of all autotrophic dinoflagellates to BPOT increased from a few percent during the May–June–July period to ∼10% during the August–September period. In situ mechanically stimulable bioluminescence was reduced when underwater scalar irradiance (wavelengths 400–700 nm) was greater than 0.1 μmol photons m−2 s−1.

A Seasonal Analysis of the Armoured Dinoflagellates of Loch Eriboll, North Scotland

The armoured planktonic dinoflagellates present at a site adjacent to a floating fish-farm in Loch Eriboll, North Scotland, were studied by surface net-sampling, mainly at two-weekly intervals, over a period of four years 1990–1993. A total of 62 species was recorded. Some dinoflagellates were present at all times of the year but they reached their lowest numbers in May, during the spring diatom bloom, and their highest numbers in mid-summer. There was usually a seasonal pattern in which the most abundant dinoflagellate during the early summer was the heterotrophic species Protoperidinium ovatum, and this was followed in the later summer by the autotroph Ceratium fusus. In 1993 the pattern was rather different, with Gonyaulax species abundant in June and, later in the year, both Protoperidinium cerasus and P. excentricum having periods of abundance. Potential toxin-producing dinoflagellates, Alexandrium tamarense (PSP) and Dinophysis acuminata (DSP), were found in small numbers.

PHOTOINHIBITION OF MECHANICALLY STIMULABLE BIOLUMINESCENCE IN THE AUTOTROPHIC DINOFLAGELLATE CERATIUM FUSUS (PYRROPHYTA)1

ABSTRACT Ceratium fusus (Ehrenb.) Dujardin was exposed to light of different wavelengths and photon flux densities (PFDs) to examine their effects on mechanically stimulable bioluminescence (MSL). Photoinhibition of MSL was proportional to the logarithm of PFD. Exposure to I μmol photons·m−2s−1 of broadband blue light (ca. 400–500 nm) produced near‐complete photoinhibition (≥90% reduction in MSL) with a threshold at ca. 0.01 μmol photons·m−2·s−1. The threshold of photoinhibition was ca. an order of magnitude greater for both broadband green (ca. 500–580 nm) and red light (ca. 660–700 nm). Exposure to narrow spectral bands (ca. 10 nm half bandwidth) from 400 and 700 nm at a PFD of 0.1 μmol photons·m−2·s−1 produced a maximal response of photoinhibition in the blue wavelengths (peak ca. 490 nm). A photoinhibition response (≥ 10%) in the green (ca. 500–540 nm) and red wavelengths (ca. 680 nm) occurred only at higher PFDs (1 and 10 μmol photons·m−2·s−1). The spectral response is similar to that reported for Gonyaulax polyedra Stein and Pyrocystis lunula Schütt and unlike that of Alexandrium tamarense (Lebour) Balech et Tangen. The dinoflagellate's own bioluminescence is two orders of magnitude too low to result in self‐photoinhibition. The quantitative relationships developed in the laboratory predict photoinhibition of bioluminescence in populations of C. fusus in the North Atlantic Ocean.

Distribution and activity of microorganisms in coastal waters off the Netherlands and Germany

Coastal waters up to 90 km off the coast of the Netherlands and Germany were investigated with the RV ‘Friedrich Heincke’ at 21 stations in July 1987. Hydrographic, chemical and biological parameters were measured simultaneously, such as temperature, salinity, oxygen saturation, adenosine triphosphate (ATP) concentrations and electron transport system (ETS) activities. The mean surface temperature was 16°C, salinity distribution showed a tongue of high salinity in the Southern Bight and coastal areas of low values by river input from the Rhine and Elbe. The mean oxygen concentration was 102.4%, with the highest percentages northwest of Helgoland and the lowest near Scheveningen and Cuxhaven. The ecosystem parameters of ATP-biomass and respiratory ETS-activity showed a distribution pattern corresponding to the inflow of clear Channel water and nutrient-rich river water. Highest biomass values and respiratory activities were found near Texel and northwest of Helgoland. The distribution patterns of microplankton species were more patchy. Distribution patterns are shown of phytoplankton species such as Ceratium fusus, Phaeocystis spec., Rhizosolenia shrubsolei, and Mesodinium rubrum and various groups of microplankton. The highest numbers of Ceratium were found near Helgoland, of Phaeocystis near Terschelling and Cuxhaven, of Rhizosolenia near Texel and Langeoog and of Mesodinium near the Dutch coast and north of Borkum. Concentrations of bacteria were determined both by cultivation and epifluorescence microscopy methods. The numbers obtained by the pour-plate method varied much more than those determined by the direct-count method. At all stations, oil-degrading bacteria were found. The numbers of bacteria able to degrade mineral oil were higher than the numbers of bacteria able to degrade a tetradecane-pentadecane mixture. Biological oxygen demand (BOD) was measured with and without oil additions after incubation of 5, 10 and 15 days and a potency to degrade oil was shown. Beside the mapping of respiratory activity by the ETS-method, the real oxygen uptake at in situ temperatures was measured in a few samples with short incubation. An ETS/R ratio of 4.1 was estimated.

Diel bioluminescence in heterotrophic and photosynthetic marine dinoflagellates in an Arctic fjord

Oceanic and coastal bioluminescence in surface waters, in many instances, is produced by microscopic dinoflagellates. Their light emission is usually observed at a maximum during the night hours and markedly inhibited during the day. This diel periodicity has never been observed in situ for identified species and never before in heterotrophic Protoperidinium dinoflagellates. Pronounced differences in stimulable bioluminescence measured with bathyphotometers in Vestfjord, Norway in September 1990 correlated with simultaneous ship-board laboratory experiments. Cells of both the photosynthetic Ceratium fusus and heterotrophic Protoperidinium curtipes showed a pronounced inhibition of bioluminescence during the day and maximum bioluminescence at night.

Spatial and seasonal changes in the species composition of armored dinoflagellates in the Southwestern Atlantic Ocean

To compare the spatial and temporal (seasonal) distribution of dinoflagellates, vertical net hauls were taken along similar cruise tracks in the Scotia Sea, Weddell Sea and across the Polar Front Zone in the austral spring and the austral fall. Sixty-three species of armored dinoflagellates were identified and enumerated. Chisquare and hierarchical cluster analyses were performed to define spatial and seasonal patterns in genera and species assemblages. The dominant genera were Protoperidinium, Dinophysis and Ceratium. The Polar Front Zone was an important biogeographical barrier with Blepharocysta, Gonyaulax, Heteroschisma, Oxytoxum and Podolampas occurring mainly north of the Front. Species found primarily in the austral spring were Ceratium fusus, Ceratium lineatum, Dinophysis antarctica, Dinophysis simplex, Gonyaulax digitale, Protoperidinium pyriforme and Protoperidinium variegatum. Austral fall species included Dinophysis tuberculata and Protoperidinium elegantissum. Distribution of armored dinoflagellates in the Southwestern Atlantic Ocean is influenced at the generic level by spatial considerations, particular with relation to the Polar Front Zone, whereas species composition can be effected by both region and season.

Microplankton assemblages in three Bias Baixas (Vigo, Arosa and Muros, Spain) with a subsurface chlorophyll maximum: their relationships to hydrography

During summer 1984, when coastal upwelling had diminished, a subsurface chlorophyll maximum (SCM) was found in 3 Galician nas which are characterized by strong thermal stratification and a nutricline at 10 to 30 m depth. The SCM formed directly above the nutricline and was composed mainly of diatoms, although the dinoflagellates Ceratiurn horridurn and Ceratium fusus and the ciliate Mesodiniurn rubrum were also present. The contribution of M. rubrum was especially important in the center of the Ria de Muros. It was possible to recognize 3 phytoplankton assemblages by means of principal component analysis. Assemblage 1, composed of heterotrophic dinoflagellates and cil~ates, was found above the SCM, indicating a possible vertical segregation in the feeding mode when an SCM is formed in the rias. Assemblage 2 , consisting of flat d~noflagellates (Dinophysis spp.), elongated diatoms (Nitzschia delicatissima, Rhizosolenia alata gracillina, Nitzschia seriata-like) and the dinoflagellates C. horridum and C. fusus, was present in more oceanic stations, suggesting some kind of interchange between rias and ocean. A third assemblage (diatoms) showed a marked neritic distribution, and was found below the SCM in waters with higher nutrient concentrations. Similarly, canonical correlation analysis showed that all the phytoplankton were characteristic for a post-bloom period, when important trophic relationships began establishing themselves in the system. However, Assemblage 1 was more heterotrophic in character than Assemblage 2. Within this general background there were differences among nas related to hydrography. In Arosa, with a hydrographic structure suggesting more mixing than in the other 2 rias, a cluster composed of diatoms was more abundant and frequent. Muros, with the strongest fluvial input, occupied an intermediate position between Arosa and Vigo.

On the Analysis of Competition Within Two-Species Mixtures of Plants

Based on the investigation data of 133 samples from 30 grid stations in the Fujian-Guangdong coastal upwelling region (21.6 degrees - 24.3 degrees N,115.7 degrees -118.7 degrees E) in 11-16 June 2009, this paper studied the phytoplankton species composition and cell abundance in the region in three dimensions (vertical, horizontal, and sectional), and approached their relations with major environmental factors. A total of 159 taxa belonging to 85 genera of 4 phyla were identified, among which, diatom was predominant, followed by dinoflagellate. Cyanophyceae mainly composed of Trichodesmium also occupied a greater proportion, but Chrysophyceae was only checked out in the upper 10 m water layer at coastal stations. The dominant species were Rhizosolenia alata f. gracillma, Thalassionema nitzschioides, Pseudonitzschia pungens, Skeletonema costatum, Thalassionema frauenfeldii, Paralia sulcata, Guinadia striata, Trichodesmium thiebautii, Ceratium fusus, and Gyrodinium spirale. Most of the phytoplankton taxa were cosmopolitan species, followed by warm-water species, while tropic high-salinity or oceanic eurythermal species were lesser. The cell abundance of the phytoplankton was average of 67.59 x10(2) ind x L(-1). In vertical profile, the cell abundance of the phytoplankton was the highest in surface water, and decreased with water depth. In horizontal and sectional profiles, the cell abundance had no definite patterns, but the high abundance region was in Nanao Island water area, being anastomosed with the center of upwelling region, which indicated that the weak and small intensity of deep-sea water upwelling caused lesser phytoplankton cell abundance and superposition. The comparatively high phytoplankton cell abundance in the four sections (B, C, D, E) along Nanao-Zhangpu was resulted from the upwelling from Taiwan Bank. The phytoplankton cell abundance had a significant positive correlation with the PO4(3-) concentration in the upper 10 m water layer, but no correlation with the dissolved inorganic nitrogen (DIN) concentration. Thereby, to study the eco-physiological responses of phytoplankton species to nutrient stress would be helpful to reveal the formation mechanism of algal bloom in upwelling region.

中海,宍道湖の湖沼調査

This investigation were made in the summer of 1949 in the whole region of Nakano-umi which could not be researched last year. In research of 1948 the plankton species have been found 53, but 85 species were found in this time. The increase of the plankton seems to be mainly due to the fact that we researched the region of the Japan Sea also. Zooplankton is superior to phytoplankton in species but less predominant in amount. Diatoms are the most abundant among the phytoplankton, 25 species have been found. The Copepoda and Cladocera are the most important in the zooplankton of this lake. As the important species we can show the following: Rhizosolenia semispina, Thalassiothrix nitzschioides, Haemiaulus Hauchii, Chaetoceras decipiens, Leptocylindrus danicus, Nitzschia seriata, Ceratium fusus, Pyrophacus horologicum, Oithona nana, Penilia schmackeri, Evadne tergestina. Most of these usually distributed on the coast of Japan Sea.

浦之内湾の研究(豫報)海洋條件ご浮遊生物

The present report has been written in the hope to give a preliminary account on the hodrobiological feature of Uranouchi Bay. The data so far obtained shows that Uranouchi Eay behaves like a salt lake though it communieates with outer sea through a narrow and shallow canal The development of thermal and chemical stratifications in this bay are very prominent, the thermal stratification being direct from January to September, and indiroct from October to Febru ?? ry. The direct stratification of dissolved oxygen is set in April when the water temprature is 15.0°C. Such a stratification is kept so long as the upper layer shows low salinity as it makes the stratification stable. It is, however, often disturbed when the density of surface water rises due to the strong evaporation of summer days, which causes the vertical circulation of water. The saturation percentage of oxygen ranged between 15.7% (August, 1944) and 160.6% (June 1943), the latter value probably being due to Chactoceros boreals which then vegetated. The bulk of the plankton is usu lly composed of Diatoms such as Chaetoceros Schuttii, Ch, decipiens, Ch. dydymus, Ch. diadema, Rhizosolenia hebetata, Rhizo, acuminata, Thatrix. Fraucnfddii, and Nitzschia seriata. The zooplankton which is usually of second importance in quantity, consisted of many Copepods, Euadne, Podon, Penilia, Ceratium fusus, and Noctilaca scintillans. Of zooplankton it was found that Creseis and Bolipnopsis appeared in great abundance during Summer and Autumn respectively.