scholarly journals Phytoplankton composition and functional groups in a tropical humic coastal lagoon, Brazil

2006 ◽  
Vol 20 (3) ◽  
pp. 701-708 ◽  
Author(s):  
Catharina Alves-de-Souza ◽  
Mariângela Menezes ◽  
Vera Huszar

This paper presents the composition and functional groups of the phytoplankton from Comprida lagoon, a tropical humic coastal Lagoon located in Southeast Brazil. A total of 28 taxa was found, distributed in eight taxonomic divisions as follows: 26% Heterokontophyta, 21% Chlorophyta, 21% Cyanophyta, 14% Bacillariophyta, 14% Cryptophyta, and 4% Prymnesiophyta. Twenty-three taxa were identified at the specific and infraspecific levels, from which four are new records for Brazil and two for Rio de Janeiro State. Phytoplankton of the Comprida lagoon was comprised of several flagellates, but also eukaryote and prokaryote picoplankton, filamentous cyanobacteria and several diatoms. The biomass was lower than that found in other lacustrine systems, and showed remarkable temporal variability. According to the functional-group approach, the populations formed eight groups: Q, Z, E, N, X3, X2, S1 and Y, most typical of oligo- or mesotrophic systems, tolerant to nutrient deficiency and sensitive to increased pH.

2016 ◽  
Vol 64 (4) ◽  
Author(s):  
Gerardo Umaña Villalobos

The detailed response of tropical lake phytoplankton to weather variations has been little studied, but it seems that composition varies in response to rain and wind variability over the course of the year. In order to gather more evidence on this variation, the weekly variability of phytoplankton composition was studied in Lake Bonilla, a low land (380 masl) 30m deep tropical lake, from April 2010 to May 2011. Temperature variation at several depths was recorded automatically, and measurements of dissolved oxygen, water transparency, and nutrients were performed several times during the study period. The lake showed a warm monomictic pattern, with deep mixing occurring during the hemispherical winter, especially after a heavy rain period in December 2010. Phytoplankton was dominated by a few species: a colonial Cyanobacteria (Aphanocapsa sp., functional group F) and two colonial Chlorococaceae (Botryococcus braunii and Eutetramorus tetrasporus, both in the functional group K). Their relative dominance shifted throughout the year, following changes in water column conditions in response to weather variations. Although changes in main functional groups indicate a shift in resource availability rather than energy, it was clear that attention should also be given to particular species adaptations beyond those used for establishing functional groups.


2021 ◽  
Vol 7 (5) ◽  
pp. 333
Author(s):  
Lourdes Morillas ◽  
Javier Roales ◽  
Cristina Cruz ◽  
Silvana Munzi

Lichens are classified into different functional groups depending on their ecological and physiological response to a given environmental stressor. However, knowledge on lichen response to the synergistic effect of multiple environmental factors is extremely scarce, although vital to get a comprehensive understanding of the effects of global change. We exposed six lichen species belonging to different functional groups to the combined effects of two nitrogen (N) doses and direct sunlight involving both high temperatures and ultraviolet (UV) radiation for 58 days. Irrespective of their functional group, all species showed a homogenous response to N with cumulative, detrimental effects and an inability to recover following sunlight, UV exposure. Moreover, solar radiation made a tolerant species more prone to N pollution’s effects. Our results draw attention to the combined effects of global change and other environmental drivers on canopy defoliation and tree death, with consequences for the protection of ecosystems.


2019 ◽  
Vol 99 ◽  
pp. 130-139 ◽  
Author(s):  
Chao Wang ◽  
Zhongguan Jiang ◽  
Lizhi Zhou ◽  
Bingguo Dai ◽  
Zhuoyan Song

2021 ◽  
Vol 17 (Especial) ◽  
pp. 19-27
Author(s):  
Nelcy Aguilar Sasari ◽  
Milenka Alessandra Fernández Ledezma ◽  
Tania Araujo-Burgos

Additives are necessary substances to improve the nutritional and organoleptic properties and the shelf life of processed food. In addition, their use is regulated, and it must be declared on the food labels. Thus, the objective of this research was to determine the frequency of food additives in processed baby products in Cochabamba metropolitan area (Bolivia). Data were collected by label reading and a frequency analysis was performed by additives and by functional group. 26 baby products were found where 41 food additives were identified with an occurrence of 256 times, and a mean of 9,8 additives per product. Moreover, the functional groups most widely used are antioxidants and colorants. Finally, the most frequent additives are mostly harmless, except for sodium nitrate and copper sulfate.


2021 ◽  
Vol 4 (2) ◽  
pp. 66-72
Author(s):  
Robby Candra Purnama ◽  
Annisa Primadiamanti

Kepok banana plants contain secondary metabolites such as tannins and flavonoids. Tannins and flavonoids have various properties for human health. Research has been carried out to identify secondary metabolite compounds (tannins, flavonoids, and saponins) by using the phytochemical screening method to see the functional group profile contained in the extract of kepok banana stem waste. Kepok banana stem waste was extracted in 96% ethanol, then evaporated and screened phytochemically. This extract was used to prepare effervescently. Screening results showed that tannin and flavonoids were identified by the appearance of the following color black-green and dark red, respectively. Meanwhile, saponins were negative because the foam formed had a height of 0.3 cm and did not meet the saponins' positive requirements (1-3 cm high foam and stable for 5 minutes). Identification of functional groups in the extract of kepok banana stem waste using Fourier-transform Infrared Spectroscopy (FTIR) showed that C-C stretching in the area 2927.24 cm-1, O-H stretching in the 3423.87 cm-1 area, C=O stretching in the 1648.87 cm-1 area. Also appeared bending CH2 in the region of 1421.45 cm-1, and C-C in the area of 1149.98 cm-1. The characteristics of three different formulas (A, B, and C) of effervescent have been investigated: the moisture content of 2.51%; 2.55%, and 2.52%, respectively. Then, flow rate of 8.81 g/s; 8.83 g/s; and 8.82 g/s, compressibility of 14.5%; 14.4%; and 14.5%, and a pH of 5.97; 5.98; and 5.97 respectively. All parameters are eligible.


2021 ◽  
Author(s):  
Abigail Enders ◽  
Nicole North ◽  
Chase Fensore ◽  
Juan Velez-Alvarez ◽  
Heather Allen

<p>Fourier Transform Infrared Spectroscopy (FTIR) is a ubiquitous spectroscopic technique. Spectral interpretation is a time-consuming process, but it yields important information about functional groups present in compounds and in complex substances. We develop a generalizable model via a machine learning (ML) algorithm using Convolutional Neural Networks (CNNs) to identify the presence of functional groups in gas phase FTIR spectra. The ML models will reduce the amount of time required to analyze functional groups and facilitate interpretation of FTIR spectra. Through web scraping, we acquire intensity-frequency data from 8728 gas phase organic molecules within the NIST spectral database and transform the data into images. We successfully train models for 15 of the most common organic functional groups, which we then determine via identification from previously untrained spectra. These models serve to expand the application of FTIR measurements for facile analysis of organic samples. Our approach was done such that we have broad functional group models that inference in tandem to provide full interpretation of a spectrum. We present the first implementation of ML using image-based CNNs for predicting functional groups from a spectroscopic method.</p>


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