Physico-chemical gradients and meromictic stratification in Cueva de la Mora and other acidic pit lakes of the Iberian Pyrite Belt

Twenty-three water dams located in the Iberian Pyrite Belt were studied during March 2012 (early spring) in order to carry out an environmental assessment based on diatom communities and to define the relationships between these biological communities and the physico-chemical characteristics of the dam surface water. This is the first time that a diatom inventory has been done for dams affected by acid mine drainage (AMD) in the Spanish part of the Iberian Pyrite Belt (IPB). It was found that the pH was the main factor influencing the behaviour of the diatom communities. Then, using a dbRDA approach it was possible to organize the aggrupation of diatoms into four groups in response to the physico-chemical conditions of the ecosystem, especially pH: (1) Maris, Aac, Gos, Cmora (pH 2–3); (2) Andc, San, And, Dpin (pH 3–4.5); (3) Gran, Pleon, Oliv, Lagu, Chan, SilI, SilII, Joya, Gar, Agrio, Camp, Corum (pH 4.5–6); (4) Herr, Diq I, Diq II (pH 6–7). The obtained results confirmed the response of benthic diatom communities to changes in the physico-chemical characteristics of surface water, and helped to understand the role of diatoms as indicators of the degree of AMD contamination in those 23 dams. Special attention was given to those that have an acidophilic or acid-tolerant profile (pH 2–3 and pH 3–4.5) such as Pinnularia aljustrelica, Pinnularia acidophila, Pinnularia acoricola and Eunotia exigua, which are the two groups found in the most AMD contaminated dams.

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Microbial Diversity and Its Relationship to Physicochemical Characteristics of the Water in Two Extreme Acidic Pit Lakes from the Iberian Pyrite Belt (SW Spain)

PLoS ONE ◽

10.1371/journal.pone.0066746 ◽

2013 ◽

Vol 8 (6) ◽

pp. e66746 ◽

Cited By ~ 47

Author(s):

Esther Santofimia ◽

Elena González-Toril ◽

Enrique López-Pamo ◽

María Gomariz ◽

Ricardo Amils ◽

...

Keyword(s):

Microbial Diversity ◽

Physicochemical Characteristics ◽

Iberian Pyrite Belt ◽

Sw Spain ◽

Pit Lakes

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Physico-chemical gradients and extremes

Aquatic Entomology ◽

10.1093/acprof:oso/9780199573219.003.0004 ◽

2013 ◽

pp. 54-64

Author(s):

Jill Lancaster ◽

Barbara J. Downes

Keyword(s):

Chemical Gradients ◽

Physico Chemical

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Adaptation of Coccomyxa sp. to Extremely Low Light Conditions Causes Deep Chlorophyll and Oxygen Maxima in Acidic Pit Lakes

Microorganisms ◽

10.3390/microorganisms8081218 ◽

2020 ◽

Vol 8 (8) ◽

pp. 1218

Author(s):

Javier Sánchez-España ◽

Carmen Falagán ◽

Diana Ayala ◽

Katrin Wendt-Potthoff

Keyword(s):

Iron Concentration ◽

Nutrient Distribution ◽

Low Light ◽

Physico Chemical ◽

Pit Lakes ◽

Low Diversity ◽

Photosynthetic Oxygen ◽

Characteristic Layers ◽

Harsh Conditions ◽

Phototrophic Community

Deep chlorophyll maxima (DCM) and metalimnetic oxygen maxima (MOM) are outstanding biogeochemical features of acidic pit lakes (APL). However, knowledge of the eukaryotic phototrophs responsible for their formation is limited. We aimed at linking the dynamics of phototrophic communities inhabiting meromictic APL in Spain with the formation of these characteristic layers. Firstly, the dynamics of DCM and MOM and their relation to physico-chemical parameters (photosynthetically active radiation (PAR), pH, dissolved ferric iron concentration, temperature), pigments and nutrient distribution is described; secondly, the phototrophic community composition is studied through a combination of microscopy, biomolecular and “omics” tools. Phototrophic communities of the studied APL show a low diversity dominated by green microalgae, specifically Coccomyxa sp., which have been successfully adapted to the chemically harsh conditions. DCM and MOM are usually non-coincident. DCM correspond to layers where phototrophs have higher chlorophyll content per cell to cope with extremely low PAR (<1 µmol m−2 s−1), but where photosynthetic oxygen production is limited. MOM correspond to shallower waters with more light, higher phytoplankton biomass and intense photosynthetic activity, which affects both oxygen concentration and water temperature. The main drivers of DCM formation in these APL are likely the need for nutrient uptake and photo-acclimation.

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Biofilm Susceptibility to Antimicrobials

Advances in Dental Research ◽

10.1177/08959374970110010701 ◽

1997 ◽

Vol 11 (1) ◽

pp. 160-167 ◽

Cited By ~ 289

Author(s):

P. Gilbert ◽

J. Das ◽

I. Foley

Keyword(s):

Antimicrobial Agents ◽

Soft Tissues ◽

Individual Species ◽

Biofilm Growth ◽

Chemical Gradients ◽

Microbial Biofilms ◽

Physico Chemical ◽

Solid Substratum ◽

The Individual ◽

Micro Organisms

Microbial biofilms, where organisms are intimately associated with each other and a solid substratum through binding and inclusion within an exopolymer matrix, are widely distributed in nature and disease. In the mouth, multispecies biofilms are associated not only with dental plaque and tooth decay but also with soft tissues of the buccal cavity and with most forms of periodontal disease. Organization of micro-organisms within biofilms confers, on the component species, properties which are not evident with the individual species grown independently or as planktonic populations in liquid media. While many of these properties relate to the establishment of functional, mixed-species consortia within the exopolymeric matrices, others relate to the establishment of physico-chemical gradients, within the biofilm, that modify the metabolism of the component cells. A consequence of biofilm growth that has profound implications for their control in the environment and in medicine is a markedly enhanced resistance to chemical antimicrobial agents and antibiotics. Mechanisms associated with such resistance in biofilms will form the substance of the present review. While some aspects of biofilm resistance are yet only poorly understood, the dominant mechanisms are thought to be related to: (i) modified nutrient environments and suppression of growth rate within the biofilm; (ii) direct interactions between the exopolymer matrices, and their constituents, and antimicrobials, affecting diffusion and availability; and (iii) the development of biofilm/attachmentspecific phenotypes.

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Beneath the surface: community assembly and functions of the coral skeleton microbiome

10.32942/osf.io/9yjw8 ◽

2019 ◽

Author(s):

Francesco Ricci ◽

Vanessa Rossetto Marcelino ◽

Linda Blackall ◽

Michael Kühl ◽

Monica Medina ◽

...

Keyword(s):

Microbial Community ◽

Community Assembly ◽

Dispersal Limitation ◽

Coral Host ◽

Chemical Gradients ◽

Physico Chemical ◽

Archaeal Species ◽

Coral Holobiont ◽

Coral Health ◽

Microbial Community Assembly

Coral microbial ecology is a burgeoning field, driven by the urgency of understanding coral health and slowing reef loss due to climate change. Coral resilience depends on its microbiota, and both the tissue and the underlying skeleton are home to a rich biodiversity of eukaryotic, bacterial and archaeal species that form an integral part of the coral holobiont. New techniques now enable detailed studies of the endolithic habitat, and our knowledge of the skeletal microbial community and its eco-physiology is increasing rapidly, with multiple lines of evidence for the importance of the skeletal microbiota in coral health and functioning. Here, we review the roles these organisms play in the holobiont, including nutritional exchanges with the coral host and decalcification of the host skeleton. Microbial metabolism causes steep physico-chemical gradients in the skeleton, creating micro-niches that, along with dispersal limitation and priority affects, define the fine-scale microbial community assembly. Coral bleaching causes drastic changes in the skeletal microbiome, which can mitigate bleaching effects and promote coral survival during stress periods, but may also have detrimental effects. Finally, we discuss the idea that the skeleton may function as a microbial reservoir that can promote recolonization of the tissue microbiome following dysbiosis and help the coral holobiont return to homeostasis.

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Macroinvertebrate stream communities along regional and physico-chemical gradients in Western Greenland

Freshwater Biology ◽

10.1046/j.1365-2427.2001.00857.x ◽

2001 ◽

Vol 46 (12) ◽

pp. 1753-1764 ◽

Cited By ~ 41

Author(s):

Nikolai Friberg ◽

Alexander M. Milner ◽

Lars M. Svendsen ◽

Claus Lindegaard ◽

Søren Erik Larsen

Keyword(s):

Chemical Gradients ◽

Stream Communities ◽

Physico Chemical

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Migrational responses of Hymenolepis diminuta to surgical alteration of gastro-intestinal secretions

Parasitology ◽

10.1017/s003118200005469x ◽

1984 ◽

Vol 88 (3) ◽

pp. 421-430 ◽

Cited By ~ 13

Author(s):

M. V. K. Sukhdeo ◽

D. F. Mettrick

Keyword(s):

Small Intestine ◽

Hymenolepis Diminuta ◽

Migratory Response ◽

Factors Affecting ◽

Chemical Gradients ◽

Point Of Entry ◽

Physico Chemical ◽

Worm Migration ◽

Gastric Secretions ◽

Distal Flow

SUMMARYThe effects of the direction of gut flow, of injections of glucose and saline into different regions of the small intestine and of surgical re-routing or ligature of gastric, biliary and pancreatic secretions into the small intestine have been correlated with changes in the migratory response of the rat tapeworm Hymenolepis diminuta. Reversing the normal anterior to distal flow of luminal contents in the small intestine did not affect worm migration following feeding. Injections of a glucose-saline solution into the duodenum did not initiate a migratory response; similar injections into the mid- and posterior regions of the small intestine resulted in migrational responses similar to those following intragastric glucose feeding. Re-routing gastric secretions to the distal duodenum inhibited anterior migration of the worms beyond the new point of entry of gastric juices. Results following re-routing and ligation of the biliary and pancreatic secretions suggest that there is a potent cue to anteriad migration in the pancreatic secretions. Biliary secretions also appear to contain an additional migratory cue to worm migration. In order of importance the factors stimulating/inhibiting worm migration are pancreatic > gastric > biliary > glucose. The results support the hypothesis that the factors affecting worm distribution in the small intestine are interactive and synergistic, involve other luminal factors, such as 5- hydroxytryptamine and the physico-chemical gradients, and are of a regional nature such that the migratory response of a particular worm is directly related to its position in the small intestine when the cues to relocation are received.

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