The Environmental Monitoring and Assessment Program (EMAP) is a joint effort of the Office of Modeling, Monitoring Systems, and Quality Assurance and the Office of Environmental Processes and Effects Research, within the Office of Research and Development. The document has been prepared to provide information on the projects within EMAP completed in Fiscal Year 1990 and funded for Fiscal Year 1991. The document is organized into five major sections: the Introduction and Overview and four sections that contain individual Project Descriptors for the four major elements of EMAP. Sections 2, 3, 4, and 5 contain individual Project Descriptors for Resource Monitoring, Coordination Activities, Integration Activities, and Developmental Research, respectively. Additionally, each Project Descriptor is coded (to assist in budget and deliverables tracking) and indexed for easy reference. The categories used to generate the three indices at the back of the document are (1) Regions and States - EPA Regions and states in which field projects or principal research activities are or will be conducted; (2) Project Officers - responsible for managing the project, providing technical direction and guidance, and ensuring coordination among related projects; and (3) Principal Investigators - responsible for ensuring the objectives are met and the work planmore » is executed. The Principal Investigators Index is further broken down into four categories.« less

The rotifer Brachionus calyciflorus is subject to the combined influence of particulate and dissolved factors derived from the toxic cyanobacterium Microcystis aeruginosa. Toxicity manifests itself through reduction of cohort survivorship and probably though reduction of cohort reproduction. Toxic effects are seen only when there is a particulate food material available in suspension, either M. aeruginosa itself or another food type which may act as a carrier for a dissolved toxic factor. Regardless of exact mechanism, the presence of a toxic strain of this blue-green may lead to diminution of population growth of co-occurring rotifer populations.

The rotifer Brachionus calyciflorus can utilize the cyanobacterium Anabaena flos-aquae as either a sole or supplementary food source in laboratory culture. Positive population growth rates accompany food densities of 10 or 100 µg dry weight ml−1, but slightly negative rates are found at a lower density (1.0 µg ml−1). These results are consistent for rotifers feeding on two strains of A. flos-aquae, UTEX-1444 and NRC-44-1, with slightly enhanced survivorship and reproduction with the latter food. A 1:1 mixture (by dry weight) of Euglena gracilis and A. flos-aquae (NRC-44-1) produces survivorship comparable to that of control rotifer cohorts fed E. gracilis alone, but elicits significantly greater fecundity and population growth rates than found with the control food suspension at the same biomass density.

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The symbiotic fern Azolla filiculoides var. rubra, which contains a blue-green nitrogen fixing alga Anabaena azollae, fixed 164 Kg N·ha-1·ann-1 in the littoral zone of a small eutrophic lake. Associated planktonic Anabaena spp. blooms, dominated by Anabaena spiroides, fixed 29.5Kg N·ha-1·ann-1. Nitrogen fixation in both organisms was not obviously related to ambient dissolved inorganic nitrogen levels. By comparing 15N−N2 and acetylene reduction techniques, we determined a ratio of 3 moles C2H2 reduced to 1 mole of N2 fixed. Combining this with results from one diurnal investigation, it was estimated that 24% of the total daily fixation by Azolla occurred at night. Highest nitrogen fixation rates in Azolla occurred when plant density was lowest. Nitrogen fixation by planktonic Anabaena spp. generally paralleled changes in biomass. Frond breakage due to wind caused a decrease in Azolla nitrogen fixation and growth which was followed by a bloom of planktonic Anabaena spp. A second Anabaena spp. bloom was instrumental in the summer decline of Azolla. Maximum growth and nitrogen fixation of both organisms did not occur simultaneously. If physical disruption to the Azolla mat does not occur, it is likely that growth of the population would continue throughout the year.