Cellular carbon and nitrogen content and cell volume of nutritionally and morphologically diverse dinoflagellate species were measured to determine carbon to volume (C : vol) and nitrogen to volume (N : vol) relationships. Cellular C and N content ranged from 48 to 3.0 3 10 4 pgC cell 21 21 5

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.2000.45.3.0569

Carbon to volume relationships for dinoflagellates, diatoms, and other protist plankton

Communities of microscopic plant life, or phytoplankton, dominate the Earth's aquatic ecosystems. This important new book by Colin Reynolds covers the adaptations, physiology and population dynamics of phytoplankton communities in lakes and rivers and oceans. It provides basic information on composition, morphology and physiology of the main phyletic groups represented in marine and freshwater systems and in addition reviews recent advances in community ecology, developing an appreciation of assembly processes, co-existence and competition, disturbance and diversity. Although focussed on one group of organisms, the book develops many concepts relevant to ecology in the broadest sense, and as such will appeal to graduate students and researchers in ecology, limnology and oceanography.

/pdf/the-ecology-of-phytoplankton-4ev70n3jsq.pdf

The Ecology of Phytoplankton

Phytoplankton biovolume can be measured or calculated through the calculation of similar geometric models. A set of geometric models is suggested for calculating cell biovolume and surface area for 284 phytoplankton genera in China Sea waters. Thirty-one geometric shapes have been assigned to estimate the biovolume and surface area of phytoplankton cells. Reductions of error and microscopic effort are also discussed. The model has been verified by its application in the China Seas regions. The software to make these calculations is available at http://www.ouc.edu.cn/csmxy/sunjun/ biovolume.htm.

/pdf/geometric-models-for-calculating-cell-biovolume-and-surface-bse8d16ccd.pdf

Geometric models for calculating cell biovolume and surface area for phytoplankton

Bacteria and algae are the numerically dominant organisms in the plankton of lakes and the ocean and their metabolism largely controls pelagic energy flow and nutrient cycling. The purpose of this review is to examine the means by which algae and heterotrophic bacteria interact in planktonic systems. In terrestrial systems, bacterial-plant interactions have been well studied in the rhizosphere, the zone in the soil where microorganisms are influenced by plant roots (108). The concept of the "phycosphere" was introduced as a pelagic analogy to the rhizosphere (7). The phycosphere would be the zone surrounding an algal cell within which microorganisms are influenced by algal products. In considering bacterial-algal interactions, then, we should ask ourselves whether a phycosphere exists. I cite specific evidence from the literature for various types of interactions. In doing this I rely heavily on laboratory studies because relatively little field oriented work is available. I include neither the photosynthetic bacteria (e.g. Chlorobiaceae, Rhodospirillaceae) nor the large macroalgae (seaweeds) in this review. The cyanobacteria have both algal and bacterial characteristics, being prokaryotes and capable of oxygenic photosynthesis. As planktonic, aerobic photo-autotrophs the cyanobacteria clearly belong with the phytoplankton in terms of this review.

Interactions between bacteria and algae in aquatic ecosystems

Trait-based approaches to community structure are increasingly used in terrestrial ecology. We show that such an approach, augmented by a mechanistic analysis of trade-offs among functional traits, can be successfully used to explain community composition of marine phytoplankton along environmental gradients. Our analysis of literature on major functional traits in phytoplankton, such as parameters of nutrient-dependent growth and uptake, reveals physiological trade-offs in species abilities to acquire and utilize resources. These trade-offs, arising from fundamental relations such as cellular scaling laws and enzyme kinetics, define contrasting ecological strategies of nutrient acquisition. Major groups of marine eukaryotic phytoplankton have adopted distinct strategies with associated traits. These diverse strategies of nutrient utilization can explain the distribution patterns of major functional groups and size classes along nutrient availability gradients.

The role of functional traits and trade‐offs in structuring phytoplankton communities: scaling from cellular to ecosystem level

Microalgal biovolume is commonly calculated to assess the relative abundance (as biomass or carbon) of co-occurring algae varying in shape and/or size. However, a standardized set of equations for biovolume calculations from microscopically measured linear dimensions that includes the entire range of microalgal shapes is not available yet. In comparison with automated methods, the use of microscopical measurements allows high taxonomic resolution, up to the species level, and has fewer sources of error. We present a set of geometric shapes and mathematical equations for calculating biovolumes of >850 pelagic and benthic marine and freshwater microalgal genera. The equations are designed to minimize the effort of microscopic measurement. The similarities and differences between our proposal for standardization and previously published proposals are discussed and recommendations for quality standards given.

Biovolume calculation for pelagic and benthic microalgae

The long-term (22 yr) record of primary production in Lake Kinneret, Israel, has been examined, together with chlorophyll and microscopically determined algal biomass, in order to discern whether there have been any significant changes in these parameters during this period. During the period 1972 through 1993, annual averages have ranged from 1,223 to 2,3 11 mg C m-2 d-l for primary production, from 127 to 246 mg m-2 for chlorophyll, and from 39.3 to 98.5 g m 2 for algal wet weight. The annual peak of these parameters was in April-May. Over 22 yr, variability in primary productivity was more closely related to changes in chlorophyll than to changes in algal biomass. No evidence was found for consistently increasing long-term trends in primary production, chlorophyll concentrations, or algal wet weight biomass from 1972-1993. Although the annual and semiannual averages of algal biomass were significantly higher in the past 11 yr than those in the previous decade, this pattern could arise from a long-term cyclical but self-compensating trend. The extended record indicates that despite population growth and intense economic development around the lake and in its catchment area, there has been no extreme eutrophication of Lake Kinneret from 1972 to 1993. We suggest that this relative resiliency of the Kinneret ecosystem is due to high ambient levels of alkalinity, calcium, and pH in the lake water acting to limit phosphorus availability, which in turn restricts the outgrowth of phytoplankton.

/pdf/primary-production-and-phytoplankton-in-lake-kinneret-a-long-5pqvp65sql.pdf

Primary production and phytoplankton in Lake Kinneret: A long‐term record (1972‐1993)

Lakes of the Warm Belt

Lake Kinneret is a subtropical monomictic lake characterized by a Pyrrhophyta-Chlorophyta assemblage, supplemented by Cyanophyta in some years. Concerning their abundance and seasonal occurrence, the phytoplanktonic algae belong to two groups: algae appearing in quantity at a definite annual period and algae present throughout the year. Four stages of algal succession occur in the lake. There is a marked periodicity in the phytoplankton composition with a high standing stock in winter-spring, due to the dinoflagellate water-bloom, and a low one during the summer months, related to the high stability of summer stratification. The annual succession at the species level has been an almost constant event in the lake for many years.

Phytoplankton periodicity in a subtropical lake (Lake Kinneret, Israel)

SUMMARY

The yearly bloom of Peridinium cinctum f. westii (Lemm.) Lef. in Lake Kinneret is described and compared with the distribution of dinoflagellates in other freshwater bodies. The physical conditions required by the Wyatt and Horwood model do not fit the actual physical events accompanying the onset of the bloom. In situ measurements of the percentage of cells in division were undertaken to clarify various points about the internal dynamics of the population. The exponential increase of the population occurs when the diurnal percentage of cells in division is not higher than 10–15%. This percentage increases up to 45% in late February–March, but does not cause any increase of population. At this period, the loss rate is nearly equal to the rate of cell increase and is interpreted as massive mortality.

Utsa Pollingher

Papers

Biovolume calculation for pelagic and benthic microalgae

Primary production and phytoplankton in Lake Kinneret: A long‐term record (1972‐1993)

Lakes of the Warm Belt

Phytoplankton periodicity in a subtropical lake (Lake Kinneret, Israel)

Phased division of peridinium cinctum f. westii (dinophyceae) and development of the lake kinneret (israel) bloom1,2