BIOVOLUME CALCULATION FOR PELAGIC AND BENTHIC MICROALGAE

Tropical Diversity, 2019

Resumo A estimativa do biovolume celular, baseada em medidas de dimensões lineares da forma, adaptadas a modelos geométricos padronizados, é importante para o estudo da ecologia do fitoplâncton. Contudo, cálculos demorados são demandados para a estimativa do biovolume a partir de medidas lineares. Neste trabalho, uma ferramenta de software simples é apresentada para auxiliar no cálculo do biovolume das amostras de fitoplâncton, usando modelos geométricos e observações microscópicas convencionais. O software BioCalc implementa as fórmulas mais recentes disponíveis na literatura para calcular o biovolume celular com base em um conjunto de 31 formas geométricas. Palavras-Chave: biovolume, fitoplâncton, morfometria, software. Abstract The estimate of cell biovolume, based on measurements of linear dimensions of shapes adapted to standard geometric models, is important for the study of phytoplankton ecology. However, time-consuming calculations are required for the estimation of biovolume from linear measurements. In this paper, a simple, user-friendly multiplatform software tool is presented to aid in the calculation of the biovolume of phytoplankton samples, using geometric models and conventional microscopic observations. The BioCalc software implements the most recent formulae available in the literature for calculating cell biovolume on the basis of a set of 31 geometric shapes.

2007

Although many studies measure the abundance of benthic microalgae (BMA), at the meters squared scale, comparing these studies is difficult due to the variety of sampling, extraction, and analysis techniques. This difficulty is exacerbated by the fact that BMA abundance has high spatial and temporal variability, at all spatial scales. A suitable standard sampling regimen would reduce variation in estimates due to different sample collection and processing greatly facilitating comparisons between studies. This study examined the effect of varying the volume of extraction solvent, sampling core diameter, and sample replication on BMA biomass estimates. Key findings, applicable to all spatial scales, to accurately determine biomass were the use of a minimum sediment to extraction solvent ratio of 1:2 and use of a sampling core diameter of 19 mm. Across a wide range of sediment types, at the meters squared scale and using spectrophotometric techniques, a minimum replication number of 8 was found to be appropriate. We report the significant effect coring depth and units of expression have on BMA biomass estimates across a range of sediment types, highlighting the potential pitfalls when comparing studies.

Hydrobiologia, 2000

A computerized counting program for algae and other microscopic bodies, named Algamica, is presented here. This program is a revised version of the original computer counting program of Hamilton published in 1990. This DOS-based software can enumerate all types of microscopic algae (i.e. phytoplankton, periphyton, diatoms), for which adequate expression of results are provided. Automated calculations of densities, biovolumes, surface areas and carbon biomass are available at the termination of each sample count. A simple counter for other micro-organisms is also available. A comprehensive guide manual file has been added to allow for a friendly first contact with the program and its options. This software conforms to current enumeration methodology. This version is available for PC computers, from website Algamica.ibelgique.com. Minimum required memory is 200 KB.

Aquatic Botany, 1998

Benthic microalgae are ubiquitous in Port Phillip Bay, southern Australia, where they occupy the dominant soft sediment habitats of this semi-enclosed marine system. Sediment associated chlorophyll a and pheophytin a has been examined as a surrogate estimate of benthic microalgal biomass. The distribution of benthic microalgal biomass, in relation to water depth and sediment characteristics, and the variation of benthic microalgal biomass across a range of spatial scales are discussed. Benthic microalgal biomass was vertically distributed with a significantly greater biomass associated with the surficial sediment stratum (0±10 mm) compared to the deeper sediment stratum (10±20 mm). Sediments exhibited a significantly greater benthic microalgal biomass when associated with shallow water sites as compared to deep water sites. Sediment type dissimilarities for benthic microalgal biomass were not significant. The depth to which light penetrates both the water column and the surficial sediment may limit the distribution of benthic microalgal biomass. Benthic microalgal biomass followed a similar distribution to the total organic matter content of surficial sediments indicating that sediment geochemical processes such as nutrient release from the breakdown of organic matter may be important in determining the distribution of benthic microalgal biomass. Important scales of spatial variation occurred at distances in the order of >10 km, 50 m and <2 m, whereas, scales in the order of 1 km and 10 m were comparatively unimportant. An appropriate sampling strategy to adequately examine benthic microalgal biomass in Port Phillip Bay is suggested. # 1998 Elsevier Science B.V.

Journal of Applied Phycology, 2016

Doriane Stagnol, Marine Macé, Christophe Destombe, Dominique Davoult. Allometric relationships for intertidal macroalgae species of commercial interest.

Determining the biomass of microbial plankton is central to the study of fluxes of energy and materials in aquatic ecosystems. This is typically accomplished by applying proper volume-to-carbon conversion factors to group-specific abundances and biovolumes. A critical step in this approach is the accurate estimation of biovolume from two-dimensional (2D) data such as those available through conventional microscopy techniques or flow-through imaging systems. This paper describes a simple yet accurate method for the assessment of the biovo-lume of planktonic microorganisms, which works with any image analysis system allowing for the measurement of linear distances and the estimation of the cross sectional area of an object from a 2D digital image. The proposed method is based on Archimedes' principle about the relationship between the volume of a sphere and that of a cylinder in which the sphere is inscribed, plus a coefficient of 'unellipticity' introduced here. Validation and careful evaluation of the method are provided using a variety of approaches. The new method proved to be highly precise with all convex shapes characterised by approximate rotational symmetry , and combining it with an existing method specific for highly concave or branched shapes allows covering the great majority of cases with good reliability. Thanks to its accuracy, consistency , and low resources demand, the new method can conveniently be used in substitution of any extant method designed for convex shapes, and can readily be coupled with automated cell imaging technologies, including state-of-the-art flow-through imaging devices.

Applied Spectroscopy Reviews, 2009

Microalgae are key primary producers and their biomass is widely applied for the production of pharmaceutics, bioactive compounds and energy. Conventionally, the content of algal chlorophyll is considered an index for algal biomass. However, this study, we estimated algal biomass by direct measurement of total suspended solids (TSS) and correlated it with chlorophyll content. The results showed mean chlorophyll-a equal to 1.05 mg/L; chlorophyllb 0.51 mg/L and chlorophyll-a+b 1.56 mg/L. Algal biomass as 161 mg/L was measured by dry weight (TSS). In statistical t-tests, F-tests and all the tested growth models, such as linear, quadratic, cubic, power, compound, inverse, logarithmic, exponential, s-curve and logistic models, we did not find any discernible relationship between all chlorophyll indices and TSS biomass. Hence, the conventional method of chlorophyll measurement might not be a good index for biomass estimation.