Phytoplankton Composition and Biomass

For investigating the horizontal component of phytoplankton distribution, we consider only surface samples or depth-integrated samples of the upper 10 m. Three main gradients have to be distinguished in this horizontal pattern  

FIGURE 15.1 Chi a distribution in surface water (1 m depth) in four coastal regions [(a) (c) September 1995, (d) July 1993]. The transects (with station numbers at the end points) refer to Fig. 15.2. (from Wasmund et al. 1999b, modified). 

Mean phytoplankton biomass decreases within the Gulf of Bothnia from the south to the north probably because of the shorter vegetation period (Andersson et al., 1996). In the Gulf of Finland, the spring phytoplankton biomass increases from west to east, corresponding to the gradient in winter nutrient concentrations (Jaanus and Liiva, 1996). 

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L. Lampert, B. Queguiner, T. Labasque, A. Pichon and N. Lebreton, Spatial variability of phytoplankton composition and biomass on the eastern continental shelf of the Bay of Biscay (north-east Atlantic Ocean). Evidence for a bloom of Emiliana huxleyi (Prymnesiophyceae) in spring 1998. Coni. Shelf Res. 22 (2002) 1225-1247. 

Makarewicz J. C., Eewis T. W., and Bertram P. (1999) Phytoplankton composition and biomass in the offshore waters of Eake Erie pre- and post-Dreissena introduction (1983-1993). J. Great Lakes Res. 25, 135-148. 

In the development of the populations of planktonic and bottom algae one can trace the seasonal dynamics of the phytocoenosis represented by the alternation of the dominating species and by the changes in their abundance and biomass. In the years different with respect to the climatic conditions, the species composition as well as the dynamics of the abundance and production of algae strongly varies. With respect to the level of the primary production, the Black Sea ecosystem may be referred to as a mesotrophic-type of marine basin. In mesotrophic waters, the phytoplankton consumption by zooplankton, which represents an important food object for fish with short lifecycles, proceeds more intensively than in oligotrophic waters. The coefficient of matter transfer from the primary production to the higher trophic levels is about... 

DiTullio GR, Smith WO Jr (1996) Spatial patterns in phytoplankton biomass and pigment distributions in the Ross Sea. J Geophys Res 101 18467-18477 DiTullio GR, Hutchins DA, Bruland KW (1993) Interaction of iron and major nutrients controls phytoplankton growth and species composition in the tropical north Pacific Ocean. Limnol Oceanogr 38 495-508 DiTullio GR, Grebmeier JM, Arrigo KR, Lizotte MP, Robinson DH, Leventer A, Barry JP, VanWoert ML, Dunbar RB (2000) Rapid and early export of Phae-ocystis antarctica blooms in the Ross Sea, Antarctica. Nature 404 595-598... 

Shalapyonok, A., Olson, R.J. and Shalapyonok, L.S. (2001) Arabian Sea phytoplankton during the southwest and northeast monsoon 1995 composition, size structure and biomass from individual cell properties measured by flow cytometry. Deep-Sea Research II, 48, 1231-1261. 

Phytoplankton abundance and occurrence of blooms are the parameters for which a not necessarily taxonomic determination is required. The abundance can be measured as the total count of cells and/or colonies in a unit volume of water or recalculated further into biovolume or biomass. The WFD allows use of chlorophyll a as a surrogate for phytoplankton biomass, thus it is considered a biological parameter. In fact, chlorophyll a is the most frequently measured phytoplankton metric in lakes. Not all countries have included the bloom occurrence in routine monitoring as in some areas (e.g. countries belonging to the Alpine GIG) they occur too rarely and inegu-larly (if at all). Other non-taxonomy-based metrics, like size composition and primary productivity, are successively less considered in lake monitoring schemes. 

Loss of sensitive species of minnow and dace, such as black-nose dace and fathead minnow in some waters decreased reproductive success of lake trout and walleye, which are important sport fish species in some areas Visual accumulations of filamentous green algae in the littoral zone of many lakes, in some streams Distinct decrease in the species richness and change in species composition of the phytoplankton, zooplankton, and benthic invertebrate communities, although little if any change in total community biomass or production... 

The advent of easy access to the satellite-based global positioning system (GPS) and availability of off-the-shelf portable probes and rapid analyzers for a number of water quality determinants have enabled the development of systems that can be carried on small survey vessels to map water quality conditions. Rapid data acquisition is now practical using probes and sondes for measuring temperature, conductivity, turbidity, pH, and dissolved oxygen fluorometric technologies for chlorophyll biomass and phytoplankton composition flow injection and loop flow analysis for some nutrient species and acoustic Doppler-based devices for current profiling. 

In this way, the near-linear chlorophyll-phosphorus relationship in lakes depends upon the outcome of a large number of interactive processes occurring in each one of the component systems in the model. One of the most intriguing aspects of those components is that the chlorophyll models do not need to take account of the species composition of the phytoplankton in which chlorophyll is a constituent. The development of blooms of potentially toxic cyanobacteria is associated with eutrophication and phosphorus concentration, yet it is not apparent that the yield of cyanobacterial biomass requires any more mass-specific contribution from phosphorus. The explanation for this paradox is not well understood, but it is extremely important to understand that it is a matter of dynamics. The bloom-forming cyanobacteria are among the slowest-growing and most light-sensitive members of the phytoplankton. ... 

Decomposition rates of some organic substrates are reduced. Substantial changes in the species composition of primary producers occur. The richness of phytoplankton species is reduced, while biomass and productivity of phytoplankton are not reduced by acidification. The biomass of herbivorous and predaceous zooplankton is probably reduced because of reductions in numbers of organisms and/or reduction in their average size. Many benthic invertebrates such as species of snails, clams, crayfish, amphipods, and various aquatic insects are intolerant of low pH and are seldom found in acidic lakes. However, certain large aquatic insects such as water boatmen and gyrinids are very acid tolerant and may become the top predators in some acidified lakes. Acidification of aquatic systems has major effects on fish population. 

In the preceding discussions, we assumed labile DOC and DON to be produced at rates y/c and y/N, respectively, without discussing their sources and how the production rate and the composition of the produced material would be expected to vary with food web structure. The important differences among different models can be illustrated by some examples. One potential model is that DOC production is an overflow mechanism occurring in mineral-nutrient-limited phytoplankton not able to use the photo-synthetically produced organic carbon for biomass production due to lack... 

Janse I, Van Rijssel M, Ottema A, Gottschal JC (1999) Microbial breakdown of Phaeocystis mucopolysaccharides. Limnol Oceanogr 44 1447-1457 Janse I, Zwart G, Maarel MJEC, Gottschal JC (2000) Composition of the bacterial community degrading Phaeocystis mucopolysaccharides in enrichment cultures. Aquat Microb Ecol 22 119-133 Joint I, Pomroy A (1993) Phytoplankton biomass and production in the southern North-Sea. Mar Ecol Prog Ser 99 169-182... 

Smith EM (1998) Coherence of microbial respiration rate and cell-specific bacterial activity in a coastal planktonic community. Aquat Microb Ecol 16 27-35 Smith WO Jr, Nelson DM, DiTullio GR, Leventer AR (1996) Temporal and spatial patterns in the Ross Sea phytoplankton biomass, elemental composition, productivity and growth rates. J Geophys Res 101 18455-18466 Smith WO Jr, Marra J, Hiscock MR, Barber RT (2000) The seasonal cycle of phytoplankton biomass and primary productivity in the Ross sea, Antarctica. Deep-Sea Res II 47 3119-3140... 

Valdes-Weaver, L. M., Piehler, M. F., Pinckney, J. L., Howe, K. E., Rossignol, K., and Paerl, H. W. (2006). Long-term temporal and spatial trends in phytoplankton biomass and class-level taxonomic composition in the hydrologicaUy variable Neuse-Panflico estuarine continuum, NC, USA. 

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