Diatoms centric

The ordination of 23 taxa or groups of taxa in relation to the environmental predictors was examined by means of multivariate analyses. Nutrients (nitrates, total phosphate, and ammonia), conductivity, total suspended solids and water flow were retained by the redundancy analysis (RDA) (Fig. 4). The first RDA axis (RDA1 16.6% of the variance) showed a strong correlation between nutrients and suspended solids and (negatively) water flow. Large centric diatoms and Scenedesmus sp.pl. best defined this situation, which was characteristic of the meandering zone, mostly in autumn. Other taxa (Coelastrum microporum,... 

Differences in chlorophyll concentrations between present and past records in the lower part of the Ebro do not correspond with significant changes in the distribution of phytoplankton assemblages. The general trends in the distribution of phytoplankton communities appear to be consistent with those reported in previous surveys, at least in the lower part of the river. Centric diatoms such as Aulacoseira granulata, Cyclotella sp. and Stephanodiscus sp. were dominant in autumn, spring, and early summer 1989-1990, while Scenedesmus sp., Coelastrum sp., and Pediastrum sp. were most abundant in the summer of that period [7]. 

Fig. 1. Scanning electron micrographs of diatoms prepared using the acid treatment method. Bars= 10 pm. (A) Unidentified centric diatom. (B) Interior of the frustule of Actinoptychus sp. (C) Cyclotella meneghinii. (D) Actinoptychus sp.

Sullivan M. Porgueniaperviana gen. et. sp. nov., a marine centric diatom with an unusual ocellus. JPhycol 1997 33 881-887. 

Bacillariophvceae (centric and pennate diatoms . For the most part, the diatoms are not significant producers of DMS. An exception is the estuarine species, Melosira nummuloides. In sufficient numbers (i.e. bloom situations) certain other species could be important. Therefore diatoms cannot be summarily dismissed as sources of DMS some consideration of species composition must be included. 

Rynearson TA, Armbrust EV (2000) DNA fingerprinting reveals extensive diversity in a field population of the centric diatom Ditylum brightwellii. Limnol Oceanogr 45 1329-1340... 

Tsuda, A., Takeda, S., Saito, H., Nishioka, J., Nojiri, Y., Kudo, I., Kiyosawa, H., Shiomoto, A., Imai, K., Ono, T., Shimamoto, A., Tsumune, D., et al. (2003). A mesoscale iron enrichment in the western Subarctic Pacific induces a large centric diatom bloom. Science 300, 958—961. 

Parker, M. S., and Armbrust, E. V. (2005). Synergistic effects of light, temperature, and nitrogen source on transcription of genes for carbon and nitrogen metabolism in the centric diatom Thalassiosira pseudonana (BaciUariophyceae). J. Phycol. 41, 1142—1153. 

It is now an accepted paradigm that reheving Fe limitation in HNLC areas fosters the growth and productivity of diatoms (reviewed in Wells, 2003, Fig. 38.2). In most cases, these have been pennate species (Boyd et al., 2000 Cavender-Bares et al., 1999 Coale et al., 2004 Gervais et al., 2002 Hutchins et al., 2002 Martin et al., 1991 Price et al., 1991), although centric diatoms have also bloomed after Fe enrichments in coastal Caftfomia (Firme et al., 2003 Hutchins and Bruland, 1998) and in the SEEDS open ocean experiment in the western subarctic Pacific (Tsuda et al., 2003). These diatom blooms are not necessarily followed by commensurate... 

Figure 16 (a) Diatom morphologies as depicted by Haeckel (1899-1904a). (b) Whole cell of the centric diatom Stephanodiscus showing the mineralized box and cover structure with a protruding ring of spines, 1,000X (source... 

In the northern part of the Western basin, at 24.6 m water depth, the salinity was 92 ppt and the temperature 13.7 C. The centric diatom Actinocyclus octonarius dominated the assemblage. In total, we observed at that location 33 diatom algae species. The diversity was high (Dmg = 4.8, PIE = 0.73, H = 2). Dinophytes and euglenids were absent. 

The centric diatom A. octonarius was dominant in autumn 2003 at a depth of... 

Centric diatoms M Bacillariophyta 27 Tett and Droop (1988) re-analysed for group medians... 

Maldonado MT and Price NM (1996) Influence of N substrate on Fe requirements of marine centric diatoms. Marine Ecology Progress Series 141 161-172. 

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