Scientific Papers:
Authors: Philip Doddy, Cilian M. Roden & Martin P. Gammell (2019)
Title: Nutrient pollution degrades microbialites in Lough Carra, an Irish marl lake
Journal: Aquatic Microbial Ecology Vol. 83, 203-209.
Abstract:
Marl lakes often have microbialite crusts in the littoral zone, containing a community of cyanobacteria and algae. Previous work has shown that these crusts are most prevalent in oligotrophic lakes and that crust metrics, such as chlorophyll content and green algal abundance, are correlated with total phosphorus concentration (TP) in lake waters, with no intact crusts being found when mean TP > 0.02 mg l−1. Two experiments were carried out to examine how microbialite crust communities respond to nutrient pollution. A culture experiment exposed crusts to various concentrations of nutrients and measured responses over a 43 wk period. In a parallel controlled field experiment, crusts were moved between areas of different trophic state within Lough Carra, a marl lake in the west of Ireland, to see how the community responded. In both experiments, increased nutrient conditions caused a change in relative abundances of taxa in the crust community, leading to a dominance of green algae and degradation of crusts. There were significant differences in chlorophyll concentrations between crusts grown in different nutrient environments. It was concluded that these metrics offer the prospect of a useful quality assessment method for marl lakes.
Marl lakes often have microbialite crusts in the littoral zone, containing a community of cyanobacteria and algae. Previous work has shown that these crusts are most prevalent in oligotrophic lakes and that crust metrics, such as chlorophyll content and green algal abundance, are correlated with total phosphorus concentration (TP) in lake waters, with no intact crusts being found when mean TP > 0.02 mg l−1. Two experiments were carried out to examine how microbialite crust communities respond to nutrient pollution. A culture experiment exposed crusts to various concentrations of nutrients and measured responses over a 43 wk period. In a parallel controlled field experiment, crusts were moved between areas of different trophic state within Lough Carra, a marl lake in the west of Ireland, to see how the community responded. In both experiments, increased nutrient conditions caused a change in relative abundances of taxa in the crust community, leading to a dominance of green algae and degradation of crusts. There were significant differences in chlorophyll concentrations between crusts grown in different nutrient environments. It was concluded that these metrics offer the prospect of a useful quality assessment method for marl lakes.
Authors: Philip Doddy, Cilian M. Roden & Martin P. Gammell (2019)
Title: Micobialite crusts in Irish limestone lakes reflect lake nutrient status
Journal: Biology and Environment: Proceedings of the Royal Irish Academy Vol. 119, No. 1, 1-11.
Abstract:
Many Irish limestone lakes contain a characteristic benthic crust, a microbialite layer composed of cyanobacteria, algae and inorganic mineral deposits. Previous work suggests that these crusts are influenced by lake nutrient status. The purpose of this paper was to test this hypothesis. In order to do this, it was first necessary to describe crust structure, chlorophyll content and species composition. Relative abundances of species were examined, as well as crust cover, thickness and organic content. A diverse community of filamentous and coccoid cyanobacteria was recorded, with chlorophytes and diatoms also present. Crusts were found to contain a high percentage (>75% of dry mass) of mineral particles, bound together by various filamentous cyanobacteria. Significant differences were shown between lakes of different trophic states, based on analyses of biological and physical factors. Strong correlations were found between total P, crust chlorophyll and crust community structure.
Many Irish limestone lakes contain a characteristic benthic crust, a microbialite layer composed of cyanobacteria, algae and inorganic mineral deposits. Previous work suggests that these crusts are influenced by lake nutrient status. The purpose of this paper was to test this hypothesis. In order to do this, it was first necessary to describe crust structure, chlorophyll content and species composition. Relative abundances of species were examined, as well as crust cover, thickness and organic content. A diverse community of filamentous and coccoid cyanobacteria was recorded, with chlorophytes and diatoms also present. Crusts were found to contain a high percentage (>75% of dry mass) of mineral particles, bound together by various filamentous cyanobacteria. Significant differences were shown between lakes of different trophic states, based on analyses of biological and physical factors. Strong correlations were found between total P, crust chlorophyll and crust community structure.
Authors: Philip Doddy & Cilian M. Roden (2018)
Title: The Fertile Rock: Productivity and erosion in limestone solution hollows of the Burren, Co. Clare.
Journal: Biology and Environment: Proceedings of the Royal Irish Academy Vol. 118, No. 1, 1-12.
Abstract:
The Burren, a region of extensive limestone pavement, is home to numerous solution hollows. These pools typically contain a characteristic black deposit, made up of microbial communities—mainly cyanobacterial—and inorganic mineral matter. A minority contain a red layer of the chlorophyte Haematococcus pluvialis, while others contain macroscopic Nostoc cyanobacterial colonies. This study examines the productivity and growth patterns of these communities and addresses their potential as bio-erosive agents on limestone substrates in a field experiment involving 72 pools. It investigates the role of organic enrichment in producing Haematococcus blooms, and measures concentrations of various pigments in pool communities over a 12-month period. A minimum production rate of 66g/m²/year dry organic mass was estimated and a minimum limestone denudation rate of 71mm per 1000 years. The results indicate that solution hollows are sites of elevated biomass production and erosion, and that the cyanobacterial deposit is involved in soil production and the conversion of limestone pavement into a habitat suitable for vascular plants.
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The Burren, a region of extensive limestone pavement, is home to numerous solution hollows. These pools typically contain a characteristic black deposit, made up of microbial communities—mainly cyanobacterial—and inorganic mineral matter. A minority contain a red layer of the chlorophyte Haematococcus pluvialis, while others contain macroscopic Nostoc cyanobacterial colonies. This study examines the productivity and growth patterns of these communities and addresses their potential as bio-erosive agents on limestone substrates in a field experiment involving 72 pools. It investigates the role of organic enrichment in producing Haematococcus blooms, and measures concentrations of various pigments in pool communities over a 12-month period. A minimum production rate of 66g/m²/year dry organic mass was estimated and a minimum limestone denudation rate of 71mm per 1000 years. The results indicate that solution hollows are sites of elevated biomass production and erosion, and that the cyanobacterial deposit is involved in soil production and the conversion of limestone pavement into a habitat suitable for vascular plants.
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Authors: Philip Doddy & Cilian M. Roden (2014)
Title: The nature of the black deposit occurring in solution hollows on the limestone pavement of the Burren, Co. Clare.
Journal: Biology and Environment: Proceedings of the Royal Irish Academy Vol. 114, No. 2, 71- 77.
Abstract:
The composition of the black deposit found in solution hollows on the karstic limestone of the Burren is described. The deposit is shown to consist partly of cyanobacteria, mainly in the order Chroococcales. Pigment analysis showed a mean chlorophyll a content of 37μg cm−3. A high content of the cyanobacterial pigment scytonemin indicates the importance of cyanobacteria in the deposit. The deposit also has a considerable amount of mineral matter (53% of dry mass). About 6% of pools examined contained a pink rather than black deposit; these are shown to be dominated by the chlorophycean alga Haematococcus pluvialis.
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The composition of the black deposit found in solution hollows on the karstic limestone of the Burren is described. The deposit is shown to consist partly of cyanobacteria, mainly in the order Chroococcales. Pigment analysis showed a mean chlorophyll a content of 37μg cm−3. A high content of the cyanobacterial pigment scytonemin indicates the importance of cyanobacteria in the deposit. The deposit also has a considerable amount of mineral matter (53% of dry mass). About 6% of pools examined contained a pink rather than black deposit; these are shown to be dominated by the chlorophycean alga Haematococcus pluvialis.
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Authors: Brian Nelson, Áine O'Connor, Garth N. Foster, Philip Doddy & Cilian Roden (2019)
Title: A review of Ochthebius nilssoni (Coleoptera: Hydraenidae) in western Ireland including a first report from Lough Carra.
Journal: Irish Naturalists' Journal Vol. 36, Part 2, 117-122.
Abstract:
The hydraenid water beetle Ochthebius nilssoni Hebauer, 1986 was a surprising addition to the Irish fauna in 2006 given that the species was known with certainty only from its type locality in northern Sweden (O’Callaghan et al. 2009). Between 2006 and 2010 the species was recorded
from five Irish localities all within the eastern Burren. Here we report on the discovery of the species in Lough Carra in Co. Mayo, which is a significant extension of its Irish range. We discuss the broad ecology of Ochthebius nilssoni and, based on that knowledge, list potential additional
sites and, finally, speculate on the future prospects of the Irish population.
The hydraenid water beetle Ochthebius nilssoni Hebauer, 1986 was a surprising addition to the Irish fauna in 2006 given that the species was known with certainty only from its type locality in northern Sweden (O’Callaghan et al. 2009). Between 2006 and 2010 the species was recorded
from five Irish localities all within the eastern Burren. Here we report on the discovery of the species in Lough Carra in Co. Mayo, which is a significant extension of its Irish range. We discuss the broad ecology of Ochthebius nilssoni and, based on that knowledge, list potential additional
sites and, finally, speculate on the future prospects of the Irish population.
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