Eleven species of marine planktonic representatives of the Chlorophyceae, Chrysophyceae, Bacillariophyceae, Dinophyceae and Myxophyceae have been analyzed for their chemical composition. All species rvere grown under similar physical and chemical conditions and cells were analyzed during the exponential phase of growth.Chemical analyses consisted of a proximate anal1'sis of each species for ash, protein, carbohydrate and lipid, and an analys.is for carbon, silicon and phosphorus, as rvell as quantitative determinations of the monosaccharides and amino acids in hydrol.r,'521g5 of whole cells. The principal finding of this report is that marine phytoplankton have very similar organic composition r,vhen grorvn under similar physical and chemical conditions, regardless of the size of the organism or the class to which it belongs.J. Fish. Res. Bd. Can. Downloaded from www.nrcresearchpress.com by UNIV CALGARY on 10/22/12For personal use only.

In spite of being one of the most relevant components of the biosphere, the plankton-benthos network is still poorly studied as such. This is partly due to the irregular occurrence of driving phenomena such as gelatinous plankton pulses in this realm. Gelatinous plankters rely on their life cycles and histories to exploit temporarily abundant resources with an undeniable, but often overlooked, impact on marine food webs. Dramatic increases of gelatinous filter-feeders and/or carnivores (both native and nonindigenous species) are frequently observed, and explanations of these blooms alternatively invoke ecosystem variability, climate change, unspecified anthropogenic perturbation or removal of top predators from trophic networks. Gelatinous plankters, however, are not anomalies in plankton dynamics: the recognition of the ecological importance of their pulses, based on their life cycle patterns (often involving benthic stages), is a critical breakthrough to understand the cycling diversity of plankton in space and time. The current study focuses on the many neglected aspects of the ecology and biology of gelatinous zooplankton, describes how life cycle patterns are central in marine ecology, as are the pulses of gelatinous organisms, and highlights how such a dramatic lack of knowledge can affect our understanding of the marine ecosystem as a whole.

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The experiment described by McAllister, & (II. ( 1961)) in which a phytoplankton bloom was induced to occur in a free-floating 20-ft diameter thin transparent plastic sphere has been repeated. Daily measurements were made of nutrients, particulate matter, and photosynthetic rates with less frequent assays for vitamins and dissolved organic matter. In situ light was recorded by a bolometcr.The experiment was prolonged to 100 days to study phytoplankton decay, most of this period being in the dark. The phytoplankton consisted mainly of 6 species of diatom and one large dinoflagellate. The mean composition of this crop at various stages of its development is reported by ratios involving chlorophyll a and particulate organic carbon. A detailed discussion is given of the findings of the experiment which, in general, confirmed those of the carlicr work and yielded, in addition, valuable new information.The plant cells excreted 35-4OoJo of their organic matter during growth. The CI~ method of measuring photosynthesis gave results ngreeing well with the production of particulate carbon.The growth kinetics of the bloom were dominated by the constancy of the mean cell division rates which were relatively independent of temperature and light.

Different components of the food web in the Strait of Georgia are reviewed. The phytoplankton are dominated by diatoms; however, flagellates may dominate in the winter. Chlorophyll a concentrations may range from < 1 mg∙m−3 in the winter to > 15 mg∙m−3 during blooms. The average annual primary productivity is about 280 g C∙m−2 for the strait, but it is higher in frontal areas at the north and south ends of the strait and near the Fraser River plume. Light limits primary productivity during the winter months, while nutrients (nitrogen) and grazing are the limiting factors during the late spring and summer. Turbidity and salinity effects occur near the Fraser River plume. The surface macrozooplankton community is composed chiefly of copepods. Mid- and deep-water communities consist of euphausiids, chaetognaths, and some deep-living copepods, which overwinter at depth. The standing stock of macrozooplankton (> 350 μm) to 400 m, ranges from 0.1 to 2.0 g wet wt∙m−3. Few estimates of secondary production and standing stock estimates of microzooplankton have been made. Horizontal patches of zooplankton have been encountered and may be important feeding sites for some fish. Standing stock associations of the dominant species in the food web of the strait are reasonably well known, but assessment of food web dynamics from these limited standing stock measurements is often inaccurate. There is a noticeable absence of data on how rate processes affect standing stocks, and it is particularly an understanding of these interrelationships that is needed for fisheries management. There is an urgent need for more interaction between biological oceanographers and fisheries scientists, particularly in the area of zooplankton grazing by larval fish.