Potential Phytoplankton Productivity of Three Iowa Streams

A series of experiments were conducted to test the hypothesis that the concentrations of suspended algal populations in central Iowa streams are not limited by nutrient concentrations. River water samples with their natural plankton populations were collected from the Des Moines River, Skunk River, and Squaw Creek and were cultured under controlled conditions without the addition of nutrients. In 23 of 24 experiments significant increases in algal chlorophyll a were found with an average replication factor of 14 times. The data indicate that nutrients are not limiting suspended algal densities in the streams. A second series of experiments indicated that nitrate concentrations of up to 20 mg/I nitrate-nitrogen did not inhibit algal growth in these river waters

Determining the Relationship Between Water Quality and Ulcerative Mycosis in Atlantic Menhaden

Project No. 92-15. ICMR Tech Report 93-08. The research on which the report is based was supported in part by the United States Environmental Protection Agency and the North Carolina Department of Environment, Health, and Natural Resources (EHNR), through the Albemarle-Pamlico Estuarine Study. Contents of the publication do not necessarily reflect the views and policies of the United States Environmental Protection Agency, the North Carolina Department of Environment, Health, and Natural Resources, nor does mention of trade names or commercial products constitute their endorsement by the United States or North Carolina Government.The objectives of this study were to investigate the possible causes of ulcerative mycosis (UM) in the Albemarle-Pamlico Estuary. Ulcerative mycosis is the commonest disease affecting the finfish populations of the Albemarle-Pamlico Estuary. While infectious agents have been isolated from UM lesions, the underlying environmental cause of the disease remains a mystery. We presently know very little of how water quality (including pollution) influences UM prevalence. The difficulty in reproducing the disease by simply challenging fish with the fungal pathogen suggests that environmental stress may play a very important role in disease development. Previous sampling surveys for UM that simultaneously examined water quality did not always show any consistent relationship to disease prevalence, perhaps because water quality monitored simultaneously with disease sampling may not be representative of the actual conditions that caused the disease outbreak. To obtain more reliable data on the risk factors influencing the development of UM, we placed clinically normal Atlantic menhaden in tanks at various sites along the Albemarle-Pamlico Estuary and examined them periodically for the development of UM lesions. We also simultaneously measured ambient water quality, including dissolved oxygen, salinity, temperature, pH, ammonia, nitrite, chlorophyll a, and prevalence of a new toxic dinoflagellate that we have recently discovered in the Albemarle Pamlico Estuary.Institute for Coastal and Marine Resources, East Carolina Universit

Impacts of Waste from Concentrated Animal Feeding Operations on Water Quality

Waste from agricultural livestock operations has been a long-standing concern with respect to contamination of water resources, particularly in terms of nutrient pollution. However, the recent growth of concentrated animal feeding operations (CAFOs) presents a greater risk to water quality because of both the increased volume of waste and to contaminants that may be present (e.g., antibiotics and other veterinary drugs) that may have both environmental and public health importance. Based on available data, generally accepted livestock waste management practices do not adequately or effectively protect water resources from contamination with excessive nutrients, microbial pathogens, and pharmaceuticals present in the waste. Impacts on surface water sources and wildlife have been documented in many agricultural areas in the United States. Potential impacts on human and environmental health from long-term inadvertent exposure to water contaminated with pharmaceuticals and other compounds are a growing public concern. This work-group, which is part of the Conference on Environmental Health Impacts of Concentrated Animal Feeding Operations: Anticipating Hazards—Searching for Solutions, identified needs for rigorous ecosystem monitoring in the vicinity of CAFOs and for improved characterization of major toxicants affecting the environment and human health. Last, there is a need to promote and enforce best practices to minimize inputs of nutrients and toxicants from CAFOs into freshwater and marine ecosystems

Harmful algal blooms and eutrophication : examining linkages from selected coastal regions of the United States

Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Harmful Algae 8 (2008): 39-53, doi:10.1016/j.hal.2008.08.017.Coastal waters of the United States (U.S.) are subject to many of the major harmful algal bloom (HAB) poisoning syndromes and impacts. These include paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP), amnesic shellfish poisoning (ASP), ciguatera fish poisoning (CFP) and various other HAB phenomena such as fish kills, loss of submerged vegetation, shellfish mortalities, and widespread marine mammal mortalities. Here, the occurrences of selected HABs in a selected set of regions are described in terms of their relationship to eutrophication, illustrating a range of responses. Evidence suggestive of changes in the frequency, extent or magnitude of HABs in these areas is explored in the context of the nutrient sources underlying those blooms, both natural and anthropogenic. In some regions of the U.S., the linkages between HABs and eutrophication are clear and well documented, whereas in others, information is limited, thereby highlighting important areas for further research.Support was provided through the Woods Hole Center for Oceans and Human Health (to DMA), National Science Foundation (NSF) grants OCE-9808173 and OCE-0430724 (to DMA), OCE-0234587 (to WPC), OCE04-32479 (to MLP), OCE-0138544 (to RMK), OCE-9981617 (to PMG); National Institute of Environmental Health Sciences (NIEHS) grants P50ES012742-01 (to DMA) and P50ES012740 (to MLP); NOAA Grants NA96OP0099 (to DMA), NA16OP1450 (to VLT), NA96P00084 (to GAV and CAH), NA160C2936 and NA108H-C (to RMK), NA860P0493 and NA04NOS4780241 (to PMG), NA04NOS4780239-02 (to RMK), NA06NOS4780245 (to DWT). Support was also provided from the West Coast Center for Oceans and Human Health (to VLT and WPC), USEPA Grant CR826792-01-0 (to GAV and CAH), and the State of Florida Grant S7701617826 (to GAV and CAH)

Defining Planktonic Protist Functional Groups on Mechanisms for Energy and Nutrient Acquisition: Incorporation of Diverse Mixotrophic Strategies

Arranging organisms into functional groups aids ecological research by grouping organisms (irrespective of phylogenetic origin) that interact with environmental factors in similar ways. Planktonic protists traditionally have been split between photoautotrophic “phytoplankton” and phagotrophic “microzoo-plankton”. However, there is a growing recognition of the importance of mixotrophy in euphotic aquatic systems, where many protists often combine photoautotrophic and phagotrophic modes of nutrition. Such organisms do not align with the traditional dichotomy of phytoplankton and microzooplankton. To reflect this understanding,we propose a new functional grouping of planktonic protists in an eco- physiological context: (i) phagoheterotrophs lacking phototrophic capacity, (ii) photoautotrophs lacking phagotrophic capacity,(iii) constitutive mixotrophs (CMs) as phagotrophs with an inherent capacity for phototrophy, and (iv) non-constitutive mixotrophs (NCMs) that acquire their phototrophic capacity by ingesting specific (SNCM) or general non-specific (GNCM) prey. For the first time, we incorporate these functional groups within a foodweb structure and show, using model outputs, that there is scope for significant changes in trophic dynamics depending on the protist functional type description. Accord- ingly, to better reflect the role of mixotrophy, we recommend that as important tools for explanatory and predictive research, aquatic food-web and biogeochemical models need to redefine the protist groups within their frameworks

Science and the Media: Ethics Issues

This module addresses the complex interface of research and the media; this interface necessarily involves issues of public policy, however, for the purposes of this module we will focus on media issues and touch on public policy in the Thinking Outside the Box section. For simplicity, when we refer to “media” we are speaking of journalists covering the science beat. In the Introduction we talk about the special collaboration between the media and the researcher and the challenges both face in communicating science to the public at large. We note the ethical component inherent in all communication and include quotations from various experts as to the difficulty of reporting research clearly; the role of rhetoric in discussing science is touched upon. In the Central Essay portion, Dr. JoAnn Burkholder talks about her experiences when dealing with the media and conducting her research in the glare of the public eye. Using specific situations in her work with Pfiesteria as an example, she gives advice to follow when talking with the media. In the Applied Philosophy section we talk about professional responsibility as “right balance” compare the role of the researcher with that of the journalist and talk about the values of objectivity, accuracy and honest disclosure. We ask about the responsibility to report ambiguous results. In the Major Theme section we focus on the challenge of communicating the uncertainty in science, and present a valuable resource for assistance, the NC State News Service. In the Thinking Outside the Box section we touch on public policy issues by presenting an article about the Precautionary Principle, a practice of communicating less than significant findings as having a role in public policy in environmental research. We close with some Additional Resources for further study

Environmental stressors and lipid production by Dunaliella spp. I. Salinity

Fourteen strains within four species of the marine chlorophyte genus, Dunaliella were assessed for their potential utility in sustainable biofuel production by tracking lipid production under salinity stress. A modified technique with Nile Red stain was used to screen cultures rapidly for the presence of neutral lipid content. Promising strains with visually high lipid content and high growth as cell production were selected to enhance lipid production using high salinity (hyperosmotic) stress in short-term (s to h) and long-term (≥ 24 h) bench-scale experiments (culture volume 0.1 to 3.5 L). These strains were also grown at mass culture scale (culture volume ~ 150 to 175 L). The difference in experimental scale was imposed because of the container effects shown for various algae, and in recognition of the importance of scale-up feasibility in harnessing algae for biofuel production. Saponifiable lipids were converted to fatty acid methyl esters, here referred to as total fatty acids (FAs), by direct transesterification. High salinity stress generally resulted in maximal total fatty acid (FA) content (up to 65% by dry weight) in comparison to controls (~ 10–25% total FAs by dry weight). Glycerol production, a known mechanism of osmoregulation in Dunaliella, was measured in a short-term salinity stress experiment on a promising strain and found to increase significantly 30 min to 24 h after exposure to high salinity. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to evaluate the relative expression of glyceryl-3-phosphate dehydrogenase (GPDH), one of the primary glycerol biosynthesis genes for glycerol production, during a short-term experiment with high salinity stress. GPDH was significantly expressed (≥ 2-fold when compared to the endogenous gene ACTIN) 30 min after exposure and continued to be expressed for 2 h. In general, when cellular glycerol content was low, total FAs increased as an immediate or short-term response (30 s to 30 min) to hyperosmotic stress. Responses were strain-specific and indicated both inter- and intraspecific variation. Overall, a simple high salinity adjustment significantly increased lipid production in selected strains of Dunaliella spp. The data suggest that these Dunaliella strains may incorporate a portion of the available glycerol as triacylglycerols (TAGs) or neutral lipids under short-term high salinity stress