Phaeocystis species

Fig. 1 Maximum-likelihood phytogeny (fastD-NAml) of 17 Phaeocystis species/strains and other prymnesiophytes inferred from 18S rDNA. The class Pavlovophyceae was used as outgroup. Bootstrap values are placed on the nodes that are identical from ML/NJ/MP analyses. The scale bar corresponds to two base changes per 100 nucleotides. Redrawn from Lange et al. (2002)...

Keywords Ecological niche Haploid-diploid Life cycle stages Morphotype Phaeocystis species Sexual processes... 

This section reviews the different cell types reported for the six Phaeocystis species which are considered here according to their revised taxonomic status as recommended by Baumann et al. (1994), Medlin et al. (1994) and Vaulot et al. (1994). This is particularly relevant for the species globosa, which has long been referred to as pouchetii in the previous literature (e.g., Parke etal. 1971 Kayser 1970 Admiraal and Venek-amp 1986 Veldhuis et al. 1991 Davidson and Marchant 1992a). The seasonal distribution of the different cell types in the natural environment will also be considered in order to assess their role in the life cycle. 

Table 1 Different morphotypes reported for the six Phaeocystis species recognized to date Flagellates with scales, threads and stars Flagellates with scales Flagellates without scales, threads and stars Same size range as colonial cells Colonial cells...

Method Phaeocystis species Growth phase Glucan-C to POC Reference... 

The colonization of two Phaeocystis species (Prymnesiophyceae) by pennate diatoms and other protists a significant contribution to colony biomass... 

The coexistence of Phaeocystis species with pennate diatoms and other protists, although not universally observed, is a well-known and common phenomenon (Hasle 1964 Rousseau et al. 1994 Hasle and Syvertsen 1997 Peperzak etal. 1998 Wassmann et al. 1999 Throndsen et al. 2003 Hamm and Rousseau 2003). In general, the colonization of... 

Grazer Developmental stage Phaeocystis species type/stage Obervation method References... 

Fig. 1 First factorial plane of MCA of data on crustacean grazing experiment on Phaeocystis. (A) Projections of continuous illustrative variables in the correlation circle (radius 1) and ordination of active variables Phaeocystis species (A), growth (

The Phaeocystis viruses isolated so far are species specific, i.e., they only infect one of the Phaeocystis species (Jacobsen et al. 1996 Bau-... 

To achieve successful infection a virus depends on the encounter rate and thus on the abundance of its host species. The Phaeocystis virus isolates have, however, not only a species-restricted host ranges but most often also a strain-specific spectrum of infection (Jacobsen et al. 1996 Baudoux and Brussaard 2005). Thus, not all strains of a Phaeocystis species (e.g., P. globosa) will become infected, even when coexisting in the same water mass. Factors influencing this are the ability of the virus to bind optimally to a proper host cell, as well as the sensitivity of the host to infection. 

As discussed above, some strains of the Phaeocystis species are resistant to viral infection. But even... 

Iron is a nutritive trace element whose role as a limiting agent for algal growth has been demonstrated in areas where certain Phaeocystis species (e.g., P. antarctica) are also commonly found. Viral lysis will affect the absolute concentration of iron that is potentially available for biological requirement, but may also directly affect the spe-ciation and bioavailability as iron is mostly com-plexed with organic ligands and colloids. 

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