B

0 Shapes: cyl, cylindrical; ps, prolate spheroid; sph, spherical. Source: After Montagnes et al. ( 1994).

Live cell volumeljim3!

I Log/log relationships between (a) cell carbon, (b) cell nitrogen and (c) chlorophyll-o content and cell volume in the marine phytoplankters listed in Table 1.7. Redrawn, with permission, from Montagnes et ol. (1994).

Live cell volumeljim3!

I Log/log relationships between (a) cell carbon, (b) cell nitrogen and (c) chlorophyll-o content and cell volume in the marine phytoplankters listed in Table 1.7. Redrawn, with permission, from Montagnes et ol. (1994).

30 or so species of phytoplankton, representative of various phyla and covering a good range of cell sizes, together with measured cell quotas of carbon, nitrogen, protein and chlorophyll a. The material reproduced in Table 1.7 represents but a fragment of the original. Live cell volumes cover a similar series of magnitudes as the freshwater species listed in Table 1.2. The carbon content of cells varied between 0.08 and 0.4 pg |im-3, with a mean value of 0.20. The ratio of carbon-to-nitrogen varied between 3.6 and 7.6 by mass, with a mean of 5.43. Chlorophyll a fell within the range 0.001-0.009 pg |im-3.

Some log/log relationships from the work of Montagnes et al. (1994) are plotted in Fig. 1.11. Carbon, nitrogen and chlorophyll are each closely correlated to live cell volume and in a way which is similar to the corresponding relationships among the freshwater phytoplankton. Thus (and, again, as is true for the freshwater phytoplankton), despite a remarkable diversity of phylogeny and morphology, as well as a 5-orders-of-magnitude range of cell volumes, there is an equally striking pattern of cell composition and a statistically predictable pattern of the relative quantities of the various constituents. This simple fact contributes to the fascination for students of phytoplankton ecology as the subject embraces the observable wonder of the seasonal replacement of one dominant among many species by another among others, as well as the opportunity to express the dynamics of production and attrition and of population wax and wane in empirical terms interlinked by powerful and predictable statistical relationships.

The scene is set for the subsequent chapters.

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