National Ocean Service

About: National Ocean Service is a government organization based out in Silver Spring, Maryland, United States. It is known for research contribution in the topics: Algal bloom & Population. The organization has 500 authors who have published 643 publications receiving 46096 citations.

Field Evaluation Of Real-Time XBT Systems

Abstract: The use of XBT's to measure the ocean's subsurface temperature has significantly increased over the past decade. NOAA is actively participating in an international effort to increase the number of subsurface temperature observations in support of global oceanographic and climate studies. NOAA's XBT program currently supports more than one hundred voluntary observing ships (VOS) . These vessels are responsible for more than 1 2 , 0 0 0 XBT observations each year. Determining the field performance of XBT data systems is an importance step in the quality control of these data. The purpose of this field test was to evaluate the performance of four XBT systems under field conditions. The systems evaluated were a SEAS I11 (Sippican's MK-9), a Bathy Systems' 810 XBT Controller, an ARGOS XBT system, and Oregon State University's (OSU) XBT Data Box.

Trace Element Nutrients

Abstract: In addition to regulation by major nutrients (nitrogen, phosphorus, and silicon), the productivity and species composition of marine phytoplankton communities are affected by a number of trace element nutrients (iron, zinc, cobalt, manganese, copper, cadmium, and selenium). Of these, iron has the dominant influence on carbon fixation rates and algal species diversity. It is also thought to play an important role in controlling dinitrogen fixation rates, and thus may exert an important influence on oceanic inventories of biologically fixed nitrogen. Because of these effects, iron is thought to play a key role in controlling carbon and nitrogen cycles in the ocean, including the biological transfer of carbon to the deep sea, the so-called biological CO2 pump. This pump regulates atmospheric CO2 concentrations and CO2-linked global warming. Other micronutrient metals (zinc, cobalt, copper, and manganese) have a lesser effect on productivity; but because of large differences in metal requirements among algal species, they may exert an important influence on the species composition of algal communities. The interactions between trace metals and ocean plankton are reciprocal: not only do the metals affect the plankton, but the plankton regulate the distributions, chemical speciation, and cycling of these metals through cellular uptake and regeneration processes, vertical flux of biogenic particles, cellular release of organic chelators, and mediation of redox reactions.

Filtering Erroneous Soundings from Multibeam Survey Data

Abstract: As part of its continuing efforts to improve data quality, the National Oceanic and Atmospheric Administration (NOAA) has recently implemented a "prefiltering" procedure designed to identify and remove erroneous or questionable soundings from multibeam sonar data collected in support of the United States Exclusive Economic Zone Bathymetric Mapping Programme. Since the start of the 1991 field season, a simple, yet effective, prefiltering algorithm has been incorporated into the standard post-processing software used aboard NOAA ships equipped with MicroVAX-based survey systems. In addition, the prefiltering routine is also being utilized as part of NOAA's current effort to convert its archive of older PDP-11 multibeam surveys to standard full-resolution "beam" format. The sounding verification criteria employed by the prefiltering algorithm is discussed in detail and statistical results from the first season of its implementation are presented.

Effects of chemically spiked sediments on estuarine benthic communities: a controlled mesocosm study

Abstract: Ambient sediments were collected from a reference site in the North Edisto River, SC and transferred to a laboratory facility to investigate effects of chemical contaminants on estuarine infaunal communities under controlled mesocosm conditions. Sediment contaminant slurries were prepared using dried sediments collected from the reference site and spiked with a metal (copper), a polycyclic aromatic hydrocarbon (pyrene), and a pesticide (4,4′-dichlorodiphenyltrichloroethane) to yield nominal mean effects range–median (ERM) quotients of <0.01 (no addition), 0.1, and 1.0 and applied to control, low dose (TRT A), and high dose (TRT B) treatment groups, respectively. Sediment samples for contaminant and benthic analyses were collected at the start of the experiment, 1 month after dosing, and 3 months after dosing. Near-nominal mean ERM quotients of 0.001, 0.075, and 0.818 were measured initially after dosing and remained fairly constant throughout the experiment. Measures of benthic condition, diversity, and richness were significantly reduced in both treatment groups relative to the control 1 month after dosing and persisted in TRT B at 3 months. The results demonstrate that benthic community effects can be observed at mean ERM quotients that are about an order of magnitude lower than levels that have been shown to be associated with significant toxicity in acute laboratory bioassays with single species (e.g., amphipods) in other studies.