Timothy R. Parsons

Bio: Timothy R. Parsons is an academic researcher from University of British Columbia. The author has contributed to research in topics: Phytoplankton & Zooplankton. The author has an hindex of 24, co-authored 79 publications receiving 22138 citations. Previous affiliations of Timothy R. Parsons include University of Tsukuba.

A manual of chemical and biological methods for seawater analysis

Abstract: Preface. General notes on analytical techniques. Nutrients. Soluble organic material. Particulate material. Plant pigments. Photosynthesis. Bacteria. Gases in seawater. Counting, media and preservatives. Terms and equivalents.

Biological oceanographic processes

Abstract: Biological oceanographic processes / , Biological oceanographic processes / , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Biological Oceanography: An Introduction

Abstract: Special properties affecting life in the sea. Classifications of marine environments and marine organisms. Basic ecological terms and concepts. The historical development of biological oceanography. Summary of chapter 1. The Abiotic Environment. Solar radiation. Temperature. Salinity. Density. Pressure. Surface currents. Summary of chapter 2. Phytoplankton and Primary Production. Systematic treatment. Photosynthesis and primary production. Radiation and photosynthesis. The effect of nutrients on growth rate. Physical controls of primary production. Global phytoplankton productivity. Summary of chapter 3. Zooplankton. Collection methods. Holoplankton: systematics and biology. Meroplankton. Vertical distribution. Diel vertical migration Seasonal vertical migrations. Zoogeography of the holoplankton. Summary of chapter4. Energy Flow and Mineral Cycling. Foodchains and energy transfer. Food webs. Measuring secondary production. A comparison of marine and terrestrial production. Mineral cycles. Summary of chapter 5. Nekton and Fisheries Oceanography. Nektonic crustacea. Nektonic cephalopods. Marine reptiles. Marine mammals. Seabirds. Marine fish. Fisheries and fisheries oceanography. Mariculture. Summary of chapter 6. Benthos. Benthic plants. Benthic animals. Determinants of community structure. Summary of chapter 7. Benthic Communities. Intertidal environments. Rocky intertidal shores. Kelp forests. Sand beaches. Estuaries. Coral reefs. Manogrove swamps. Deep-sea ecology. Hydrothermal vents and cold seeps.

Resilience and Stability of Ecological Systems

Abstract: Individuals die, populations disappear, and species become extinct. That is one view of the world. But another view of the world concentrates not so much on presence or absence as upon the numbers of organisms and the degree of constancy of their numbers. These are two very different ways of viewing the behavior of systems and the usefulness of the view depends very much on the properties of the system concerned. If we are examining a particular device designed by the engineer to perform specific tasks under a rather narrow range of predictable external conditions, we are likely to be more concerned with consistent nonvariable performance in which slight departures from the performance goal are immediately counteracted. A quantitative view of the behavior of the system is, therefore, essential. With attention focused upon achieving constancy, the critical events seem to be the amplitude and frequency of oscillations. But if we are dealing with a system profoundly affected by changes external to it, and continually confronted by the unexpected, the constancy of its behavior becomes less important than the persistence of the relationships. Attention shifts, therefore, to the qualitative and to questions of existence or not. Our traditions of analysis in theoretical and empirical ecology have been largely inherited from developments in classical physics and its applied variants. Inevitably, there has been a tendency to emphasize the quantitative rather than the qualitative, for it is important in this tradition to know not just that a quantity is larger than another quantity, but precisely how much larger. It is similarly important, if a quantity fluctuates, to know its amplitude and period of fluctuation. But this orientation may simply reflect an analytic approach developed in one area because it was useful and then transferred to another where it may not be. Our traditional view of natural systems, therefore, might well be less a meaningful reality than a perceptual convenience. There can in some years be more owls and fewer mice and in others, the reverse. Fish populations wax and wane as a natural condition, and insect populations can range over extremes that only logarithmic

Environmental Genome Shotgun Sequencing of the Sargasso Sea

Abstract: We have applied “whole-genome shotgun sequencing” to microbial populations collected en masse on tangential flow and impact filters from seawater samples collected from the Sargasso Sea near Bermuda. A total of 1.045 billion base pairs of nonredundant sequence was generated, annotated, and analyzed to elucidate the gene content, diversity, and relative abundance of the organisms within these environmental samples. These data are estimated to derive from at least 1800 genomic species based on sequence relatedness, including 148 previously unknown bacterial phylotypes. We have identified over 1.2 million previously unknown genes represented in these samples, including more than 782 new rhodopsin-like photoreceptors. Variation in species present and stoichiometry suggests substantial oceanic microbial diversity. Microorganisms are responsible for most of the biogeochemical cycles that shape the environment of Earth and its oceans. Yet, these organisms are the least well understood on Earth, as the ability to study and understand the metabolic potential of microorganisms has been hampered by the inability to generate pure cultures. Recent studies have begun to explore environ

Isolation of an autotrophic ammonia-oxidizing marine archaeon

Abstract: For years, microbiologists characterized the Archaea as obligate extremophiles that thrive in environments too harsh for other organisms. The limited physiological diversity among cultivated Archaea suggested that these organisms were metabolically constrained to a few environmental niches. For instance, all Crenarchaeota that are currently cultivated are sulphur-metabolizing thermophiles. However, landmark studies using cultivation-independent methods uncovered vast numbers of Crenarchaeota in cold oxic ocean waters. Subsequent molecular surveys demonstrated the ubiquity of these low-temperature Crenarchaeota in aquatic and terrestrial environments. The numerical dominance of marine Crenarchaeota--estimated at 10(28) cells in the world's oceans--suggests that they have a major role in global biogeochemical cycles. Indeed, isotopic analyses of marine crenarchaeal lipids suggest that these planktonic Archaea fix inorganic carbon. Here we report the isolation of a marine crenarchaeote that grows chemolithoautotrophically by aerobically oxidizing ammonia to nitrite--the first observation of nitrification in the Archaea. The autotrophic metabolism of this isolate, and its close phylogenetic relationship to environmental marine crenarchaeal sequences, suggests that nitrifying marine Crenarchaeota may be important to global carbon and nitrogen cycles.

Mathematical formulation of the relationship between photosynthesis and light for phytoplankton

Abstract: Eight different mathematical formulations of the photosynthesis—light curve for phytoplankton (up to and including light saturation) were recast in terms of the same two parameters: the initial slope α, and the assimilation number PmB. Each equation was tested for its ability to describe empirical data from natural populations of marine phytoplankton: the results of 188 light-saturation experiments at three coastal locations in Nova Scotia over a 2-year period. The most consistently useful mathematical representation of the data was found to be the hyperbolic tangent function.

Organic geochemical indicators of palaeoenvironmental conditions of sedimentation

Abstract: Our increasing knowledge of the geochemical processes of present-day sedimentation conditions provides a basis for evaluating the role of oxic and anoxic sedimentary environments. In particular, there are organic geochemical parameters, such as lipid composition, sulphur and organic pigments, which link Recent sediments with their geologically older counterparts, and these may therefore be used to assign the depositional palaeoenvironments of ancient sediments and petroleums.