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In JoVE (4)
- Seawater Sampling and Collection
- Large Volume (20L+) Filtration of Coastal Seawater Samples
- Small Volume (1-3L) Filtration of Coastal Seawater Samples
- DNA Extraction from 0.22 μM Sterivex Filters and Cesium Chloride Density Gradient Centrifugation
Other Publications (3)
Articles by Elena Zaikova in JoVE
JoVE General
Seawater Sampling and Collection
Department of Microbiology and Immunology, University of British Columbia - UBC
This video documents methods for collecting coastal marine water samples and processing them for various downstream applications including biomass concentration, nucleic acid purification, cell abundance, nutrient and trace gas analyses.
JoVE General
Large Volume (20L+) Filtration of Coastal Seawater Samples
Department of Microbiology and Immunology, University of British Columbia - UBC
This video documents large volume (≥20 L) filtration of microbial biomass, ranging between 0.22μm and 2.7μm in diameter, from the water column.
JoVE General
Small Volume (1-3L) Filtration of Coastal Seawater Samples
Department of Microbiology and Immunology, University of British Columbia - UBC
This video documents small volume (~1 L) filtration of microbial biomass from the water column.
JoVE General
DNA Extraction from 0.22 μM Sterivex Filters and Cesium Chloride Density Gradient Centrifugation
Department of Microbiology and Immunology, University of British Columbia - UBC
We describe a method for extraction of high molecular weight genomic DNA from planktonic biomass concentrated on 0.22 μm Sterivex filters, followed by cesium chloride density gradient centrifugation for purification.
Other articles by Elena Zaikova on PubMed
Metagenome of a Versatile Chemolithoautotroph from Expanding Oceanic Dead Zones
Oxygen minimum zones, also known as oceanic "dead zones," are widespread oceanographic features currently expanding because of global warming. Although inhospitable to metazoan life, they support a cryptic microbiota whose metabolic activities affect nutrient and trace gas cycling within the global ocean. Here, we report metagenomic analyses of a ubiquitous and abundant but uncultivated oxygen minimum zone microbe (SUP05) related to chemoautotrophic gill symbionts of deep-sea clams and mussels. The SUP05 metagenome harbors a versatile repertoire of genes mediating autotrophic carbon assimilation, sulfur oxidation, and nitrate respiration responsive to a wide range of water-column redox states. Our analysis provides a genomic foundation for understanding the ecological and biogeochemical role of pelagic SUP05 in oxygen-deficient oceanic waters and its potential sensitivity to environmental changes.
Microbial Community Dynamics in a Seasonally Anoxic Fjord: Saanich Inlet, British Columbia
Dissolved oxygen concentration plays a major role in shaping biotic interactions and nutrient flows within marine ecosystems. Throughout the global ocean, regions of low dissolved oxygen concentration (hypoxia) are a common and expanding feature of the water column, with major feedback on productivity and greenhouse gas cycling. To better understand microbial diversity underlying biogeochemical transformations within oxygen-deficient oceanic waters, we monitored and quantified bacterial and archaeal community dynamics in relation to dissolved gases and nutrients during a seasonal stratification and deep water renewal cycle in Saanich Inlet, British Columbia, a seasonally anoxic fjord. A number of microbial groups partitioned within oxygen-deficient waters including Nitrospina and SAR324 affiliated with the delta-proteobacteria, SAR406 and gamma-proteobacteria related to thiotrophic gill symbionts of deep-sea clams and mussels. Microbial diversity was highest within the hypoxic transition zone decreasing dramatically within anoxic basin waters and temporal patterns of niche partitioning were observed along defined gradients of oxygen and phosphate. These results provide a robust comparative phylogenetic framework for inferring systems metabolism of nitrogen, carbon and sulfur cycling within oxygen-deficient oceanic waters and establish Saanich Inlet as a tractable model for studying the response of microbial communities to changing levels of water column hypoxia.
Microbial Life in a Liquid Asphalt Desert
Pitch Lake in Trinidad and Tobago is a natural asphalt reservoir nourished by pitch seepage, a form of petroleum that consists of mostly asphaltines, from the surrounding oil-rich region. During upward seepage, pitch mixes with mud and gases under high pressure, and the lighter portion evaporates or is volatilized, which produces a liquid asphalt residue characterized by low water activity, recalcitrant carbon substrates, and noxious chemical compounds. An active microbial community of archaea and bacteria, many of them novel strains (particularly from the new Tar ARC groups), totaling a biomass of up to 10(7) cells per gram, was found to inhabit the liquid hydrocarbon matrix of Pitch Lake. Geochemical and molecular taxonomic approaches revealed diverse, novel, and deeply branching microbial lineages with the potential to mediate anaerobic hydrocarbon degradation processes in different parts of the asphalt column. In addition, we found markers for archaeal methane metabolism and specific gene sequences affiliated with facultative and obligate anaerobic sulfur- and nitrite-oxidizing bacteria. The microbial diversity at Pitch Lake was found to be unique when compared to microbial communities analyzed at other hydrocarbon-rich environments, which included Rancho Le Brea, a natural asphalt environment in California, USA, and an oil well and a mud volcano in Trinidad and Tobago, among other sites. These results open a window into the microbial ecology and biogeochemistry of recalcitrant hydrocarbon matrices and establish the site as a terrestrial analogue for modeling the biotic potential of hydrocarbon lakes such as those found on Saturn's largest moon Titan.
