Molecular and morphological analyses of solitary forms of brackish Thalassiosiroid diatoms (Coscinodiscophyceae), with emphasis on their phenotypic plasticity

Abstract

Blooms of centric diatoms are a common feature in the Bilbao estuary during summer when river flow is at its lowest and water temperature is above 20ºC. To gain insight into the specific composition of these diatom blooms, net samples and cultures of estuarine isolates were analysed under the scanning electron microscope (SEM) and by molecular analyses of the Internal Transcribed Spacers 1 and 2 plus the coding region 5.8S (ITS region) and the 28S rRNA gene. Seven species of solitary centric diatoms belonging to four genera were found in the estuary including: Conticribra weissflogii, Cyclotella atomus var. atomus, Cyclotella cryptica, Cyclotella marina, Cyclotella meneghiniana, Discostella pseudostelligera and Thalassiosira pseudonana. Dominant species during blooms were C. meneghiniana and Co. weissflogii in the upper estuary and D. pseudostelligera and T. pseudonana in the middle estuary. The morphological traits used to differentiate between species pairs of similar morphology (C. meneghiniana/C. cryptica or D. pseudostelligera/D. woltereckii) were observed to vary with environmental conditions, denoting a great deal of phenotypic plasticity which would hinder accurate identification of the species when using morphological approaches alone.

Tracing the Origin of Planktonic Protists in an Ancient Lake

“…Among them, OTUs from the brackish Arctic Ward Hunt Lake were identical to the OTU_73 from Lake Baikal, which was found in 18 samples and corresponded to 0.2% of all reads in Lake Baikal (4,495 reads in total). The diatom Thalassiosira pseudonana, known from brackish waters [49] was also found in our data ( Figure S2). OTU_299 (155 reads; Figure S10) belongs to an organism with potential polar origin: it is identical to Naganishia vishniacii (Cryptococcus vishniacii), which is an enigmatic protist from Antarctic soil [50] and also was found in the meltwater from Tianshan glacier [51].…”

A comparison of the degradation behaviour of 3D printed PDLGA scaffolds incorporating bioglass or biosilica

“…1a shows the AFM images of a unicell diatom, which is approximately 8 to 10 m in diameter. This result is in agreement with the average size of C. Meneghiniana diatom (6 -18 m) from previous studies [54][55][56] . Both the AFM (Fig for processes such as waste removal and mucilage secretion 45 .The darker region on the TEM (Fig 1c) indicate a denser material, which could be a thicker section of biosilica.…”

Tracing the Origin of Planktonic Protists in an Ancient Lake

“…Among them, OTUs from the brackish Arctic Ward Hunt Lake were identical to the OTU_73 from Lake Baikal, which was found in 18 samples and corresponded to 0.2% of all reads in Lake Baikal (4495 reads in total). The diatom Thalassiosira pseudonana, known from brackish waters [54], was also found in our data ( Figure S2). Furthermore, OTU_299 (155 Among Stramenopiles, members of four MAST groups were found (Figure 4, Figure S4).…”

“…Among them, OTUs from the brackish Arctic Ward Hunt Lake were identical to the OTU_73 from Lake Baikal, which was found in 18 samples and corresponded to 0.2% of all reads in Lake Baikal (4495 reads in total). The diatom Thalassiosira pseudonana, known from brackish waters [54], was also found in our data ( Figure S2). Furthermore, OTU_299 (155 reads; Figure S10) was identical to Naganishia vishniacii (Cryptococcus vishniacii), which is an enigmatic protist from Antarctic soil [55] but was also found in the meltwater from Tianshan glacier [56].…”