The effect of copper on different phototrophic microorganisms determined in vivo and at cellular level by confocal laser microscopy

Abstract

Microbial mats are coastal ecosystems that consist mainly of cyanobacteria, primary producers in these habitats that play an important role in stabilising delta sediments. However, these ecosystems are subject to various kinds of pollution, including metal contamination, placing their survival at risk. Among heavy metals, copper is an essential metal at low doses and toxic at high doses. This metal is present in different pesticides used in rice production, a thriving agro-industry in the Ebro Delta (Spain). For several years, our group has been studying the Ebro Delta microbial mats and has developed a method for determining the effect that metals cause on cyanobacteria populations. This method is based on confocal laser microscopy coupled to a spectrofluorometer, which rapidly provides simultaneous three-dimensional information on photosynthetic microorganisms and their fluorescence spectra profiles. The current study determines the copper effect on different photosynthetic microorganisms from culture collection (Chroococcus sp. PCC 9106 and Spirulina sp. PCC 6313) and isolated from the environment (Microcoleus-like and the microalga DE2009). Comparing all results obtained it can be observed that the minimum dose of Cu that is capable of significantly altering chlorophyll a (chl a) fluorescence intensity were 1 × 10(-7) M in Chroococcus sp. PCC 9106; 1 × 10(-7) M in Spirulina sp. PCC 6313; 3 × 10(-7) M in Microcoleus and 5 × 10(-6) M in the microalga DE2009. Moreover, the sensitivity of the technique used was 1 × 10(-7) M.

Contrasted effects of natural complex mixtures of PAHs and metals on oxygen cycle in a microbial mat

“…On average, respiration and photosynthesis were not significant different than those observed in control treatment although the water of the retention basin of the oil refinery was strongly contaminated by heavy metals, especially in copper. The copper concentration (38 lg L À1 ) measured in September is closed to the EC50 (65 lg L À1 ) determined for the mat forming cyanobacterium Microcoleus-like (Seder-Colomina et al, 2013). The absence of inhibition by copper might be explained by its low bioavailability, copper can be bound to dissolved organic matter (e.g.…”

Seaweed Bioactive Compounds against Pathogens and Microalgae: Potential Uses on Pharmacology and Harmful Algae Bloom Control

“…Copper sulfate (CuSO 4 ·5H 2 O) used to be the most popular algicide. Although the treatment was usually effective by killing cyanobacteria, side effects occurred: copper is toxic to many other aquatic organisms including fish [ 2 ] and the increase in dead algal biomass led to oxygen depletion and an increase in the release of phosphorus from the sediments, resulting in the reoccurrence of the blooms.…”

“…Various strategies, including physical, chemical, and biological methods have been proposed for controlling or mitigating Harmful Algal Blooms (HABs). Chemical agents such us copper sulfate [ 2 ], potassium chloride [ 3 ], and endothall [ 4 ] have been used. Mechanical control involves the use of filters, pumps, and barriers [ 5 ].…”

Recent Advances in the Application of Chlorophyll a Fluorescence from Photosystem II

“…It also harms human health. For example, Cu is an essential metal that can bring high toxicity at low concentrations (72). Plants are very sensitive to heavy-metal stress.…”