Satellite estimation of chlorophyll-a concentration and phytoplankton primary production in the Sea of Azov

Phytoplankton plays a critical role in determining light fields of the world’s oceans, primarily through absorption of light by photosynthetic pigments (see Chapters 1 to 5). Consequently there has been considerable interest from optical researchers in determining phytoplankton absorption. Conversely, from the biological point of view, this absorption assumes paramount importance because it is the sole source of energy for photosynthesis and thus should be central to direct estimates of primary production. There are two logical parts in determining this effect of phytoplankton and in estimating primary production. One is the estimation of abundance, and the other is estimation of specific effect or specific production rate. The earliest estimates of phytoplankton abundance were based on cell counts. From the time of Francis A. Richards’ Ph.D. dissertation, however, measurement of chlorophyll a concentration per unit of water volume, because of its relative ease, has assumed a central role in abundance estimation. Physiological studies and technological advances in optical instrumentation over the last decade lead me to question whether the continued use of chlorophyll a concentration to estimate phytoplankton abundance was wise either from the viewpoint of narrowing confidence intervals on estimates of absorption and production or from the viewpoint of mechanistic understanding of the processes involved. The measurement of chlorophyll a has become such a routine tool of biological oceanography, however, that the reasons for my heresy require elaboration. Some of the reasons are not too subtle. Chlorophyll a exists with other photosynthetic pigments in organized arrays associated with photosynthetic membranes. The function of these arrays is to harvest photons and transfer their energy to the specialized reaction center complexes that mediate photochemistry (see Chapter 9). The size of the arrays or packages and the ratio of chlorophyll a molecules to other light-harvesting pigments within the packages vary with phytoplankton cell size, total irradiance and its spectral distribution, as well as with other environmental parameters. It is well known that dark-adapted (= light-limited) cells increase their complements of photopigments. This plasticity in pigment packaging is evidenced in the variability of chlorophyll a-specific absorption coefficients. Simple optical models based only on chlorophyll a concentrations cannot be accurate or precise unless the effects of pigment packaging are considered.

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Productivity of the Psammic Algal Communities in the Near-Shore Zone of the Mesotrophic Lake Piaseczno (Eastern Poland)

Water Quality Research Journal ◽

10.2166/wqrj.2001.029 ◽

2001 ◽

Vol 36 (3) ◽

pp. 537-564 ◽

Cited By ~ 1

Author(s):

Krzysztof Czernaś

Keyword(s):

Primary Production ◽

Chlorophyll A ◽

Phytoplankton Biomass ◽

Major Ions ◽

Shore Zone ◽

Algal Communities ◽

Chlorophyll A Concentration ◽

Assimilation Number ◽

Mesotrophic Lake ◽

Near Shore

Abstract From 1986 to 1998, the primary productivity of psammic algae was investigated in the psammolittoral of Lake Piaseczno, a mesotrophic lake. The oxygen method was developed for the direct measurement of primary production of these algae based on light and dark bottles without disturbing the subsoil structure. This productivity was also estimated in an indirect way by measurement of chlorophyll a concentrations. The productivity of phytoplankton was also measured in the same zone. The correlation between the productivity of algae and the concentration of nutrients and major ions in water was calculated. During the study period, the highest production was found in the eupsammon (31.1 to 187.7 Cass·m-2·h-1), with the hydropsammon being lower (9.6 to 100.6 Cass·m-2·h-1). For phytoplankton biomass, the numbers were very low, which is typical of pristine lakes. The chlorophyll a concentration during the study period demonstrated a different pattern ranging from 53 mg·m-2 in the hydropsammon to 765 mg·m-2 in the eupsammon. The assimilation number for these communities was always <1. A positive (r >0.4) correlation was found between the primary production of the eupsammon and the psammolittoral phytoplankton, and the concentration of NH4-N, NO3-N, Ntot, PO4-P, Ptot. and K+ in the piezometer groundwater. No correlation was found between primary production, chlorophyll a concentration and the concentration of nutrients and major ions in the piezometer groundwater and psammolittoral water.

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Bacterial population dynamics, production, and heterotrophic activity in a recently formed reservoir

Canadian Journal of Microbiology ◽

10.1139/w99-058 ◽

1999 ◽

Vol 45 (9) ◽

pp. 747-753 ◽

Cited By ~ 6

Author(s):

Louis B Jugnia ◽

Rémy D Tadonléké ◽

T Sime-Ngando ◽

J Devaux ◽

C Andrivon

Keyword(s):

Primary Production ◽

Chlorophyll A ◽

Biomass Production ◽

Resource Availability ◽

Bacterial Production ◽

Standing Stock ◽

Bacterial Biomass ◽

Heterotrophic Activity ◽

Chlorophyll A Concentration ◽

Biological Variables

Seasonal and spatial fluctuations in abundance, biomass production, and potential heterotrophic activity (i.e., 14C-glucose uptake) of bacterioplankton assemblages in a 1-year-old reservoir (the Sep Reservoir, Puy-de-Dôme, France) were examined concurrently with water temperature, phytoplankton chlorophyll a concentration, and primary production (PP). Based on the values observed for these biological variables, the Sep Reservoir was considered to have evolved to an oligo-mesotrophic state. Spatiotemporal variations of bacterial variables were a consequence of the seasonal evolution of the reservoir coupled with the resource availability. Multivariate regression analyses suggest that about 14 and 26% of the variance in bacterial standing stock and activity may be explained by the physical environment (i.e., temperature) and a resource availability index (chlorophyll a concentration or primary production), respectively. A carbon budget indicated that 4-126% (mean = 20%) of the ambient PP may be channeled through the microbial loop via bacterial biomass production. Heterotrophic bacterial production in the Sep Reservoir may therefore, on occasion, represent a significant source of carbon for higher order consumers.Key words: reservoirs, plankton, bacteria, heterotrophic uptake, primary and bacterial production.

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