Andrew Robertson

Monitoring the ecological condition of estuaries in the United States

The purpose of the Environmental Monitoring and Assessment Program/ Estuaries component (EMAP‐E) is to determine the current status, extent, changes, and trends in ecological indicators of the condition of the nations estuarine resources on a regional and national basis. Monitoring activities in the Virginian (Mid‐Atlantic) and Louisianian (Gulf of Mexico) Provinces focus on measurements describing the benthic community, the fish community, water quality, levels of sediment and tissue contamination, sediment toxicity, wetlands extent/condition, and seagrasses extent/condition. Estuarine monitoring is based on an EMAP‐E probability‐based sampling design conducted over a 60‐day period during July‐September of each year. Monitoring activities in the Virginian Province began in 1990 and have continued annually while monitoring in the Louisianian Province was initiated in 1991. The results of 1990 monitoring in the Virginian Province show that 20% of the sediments of the Mid‐Atlantic region suffered from poor...

Great Lakes Eutrophication: The Effect of Point Source Control of Total Phosphorus

A mathematical model of the Great Lakes total phosphorus budgets indicates that a 1 milligram per liter effluent restriction for point sources would result in significant improvement in the trophic status of most of the system. However, because large areas of their drainage basins are devoted to agriculture or are urbanized, western Lake Erie, lower Green Bay, and Saginaw Bay may require non-point source controls to effect significant improvements in their trophic status.

Environmental quality of Long Island Sound: Assessment and management issues

Estimated pollutant loadings to Long Island Sound (LIS) are presented and discussed in the context of current information on population trends and land-use characteristics within the drainage basin of the sound. For the conventional pollutants (BOD, N, and P) and for most of the metals examined, the fluxes to LIS from wastewater treatment plants approach or exceed the fluxes from riverine sources. Urban runoff is a significant source for only a few contaiminants, such as lead and petroleum hydrocarbons. Atmospheric flux estimates made for other are s are extrapolated to LIS, and this source appears to be significant for lead, zinc, polynuclear aromatic hydrocarbons, and chlorinated pesticides. Continued population growth is projected through 2010, both in the urban centers of the western sound and in the coastal counties surrounding the central and eastern portions of LIS. This growth will place increased pollution pressure on the sound and increased demands on already scarce coastal and estuarine land-use categories. Close interaction between environmental planners, managers, and scientists is required to identify effective control strategies for reducing existing pollutant stress to the sound and for minimizing the effects of future development.

Distribution of Chlorinated Organic Contaminants in Dreissenid Mussels Along the Southern Shores of the Great Lakes

Abstract Samples of dreissenid mussels were collected from 21 sites along the U.S. shores of the southern part of the Great Lakes and their connecting channels. These samples were analyzed for tissue levels of 16 chlorinated organic compounds, mostly pesticides, as well as for lipid levels. Aldrin, endrin, and lindane were found above detection levels at less than one-half of the sites, primarily at sites in Lake Michigan. Mirex was detected at nine sites mostly in Lake Ontario and the Niagara River, but also near Detroit and in Saginaw Bay. Heptachlor was detected at only two sites, both in Lake Erie. Cis-chlordane, dieldrin, hexachlorobenzene, heptachlor, trans-nonachlor, and total DDTs were detected at all or almost all of the sites. Except for hexachlorobenzene, which was highest near Buffalo, these chemicals were found at higher concentrations in Lake Michigan, especially near Milwaukee, than in the other areas studied. A comparison of the concentrations of chlorinated organic compounds to the levels of lipids showed that differences in dreissenid lipid levels among sites were not the major cause of the observed differences in concentrations in the chlorinated organic compounds. At most sampling locations, the category total DDTs was composed primarily of the DDT breakdown products DDD and especially DDE. However, a substantial percentage of the total DDTs detected at sites in eastern Lake Erie and western Lake Ontario was composed of the parent DDT compounds, suggesting the presence of a relatively recent input of this compound in this area. Comparison of the concentrations of chlorinated organic compounds measured in Great Lakes dreis-senids with concentrations of these compounds in marine mussels and oysters found generally similar levels for most of the compounds. Exceptions to this were hexachlorobenzene and mirex which had mean concentrations more than 5 times greater in mussels from the Great Lakes than from marine locations and lindane which had concentrations in mussels from the Great Lakes less than one-tenth of those from marine mussels.

An IFYGL Carbon Budget for Lake Ontario

A carbon budget was produced for each month of the International Field Year for the Great Lakes (IFYGL) year (April 1972 to March 1973) to determine the importance of the various sources and sinks of carbon. Major sources were found to be CO2 which was fixed in organic matter during primary production and inorganic carbon in tributary streams, especially the Niagara River. The major sinks were found to be inorganic carbon outflow at the St. Lawrence River and net CO2 gas exchange between the inorganic carbon pool and the atmosphere. Inflow and outflow of organic matter in rivers, sedimentation of organic and inorganic matter, ground water transport, and municipal and industrial perturbations accounted in total for less than 10% of the annual budget. The lake had an inventory of approximately 4.0 × 1010 kg of inorganic carbon and approximately an order of magnitude less organic carbon. The riverborne flux of inorganic carbon of 0.5 × 1010 was 13% of the lakes inventory, assuming complete mixing; a minimum mean residence time of 8 years can be calculated from that inventory. The seasonal cycle inherent in the fixation of carbon in primary production was primarily balanced by a complementary seasonal cycle in the air-lake CO2 gas exchange system. The lake acts as a sink for CO2 gas in the warm months when primary productivity is highest and as a source of CO2 in the colder part of the year. The IFYGL year had higher than normal rates of water flow, but this does not appear to have perturbed the inorganic carbon system. A comparison of IFYGL carbon budget results with corresponding estimates calculated for a typical year from historical data shows no major differences.

Annotated Checklist of the Free-Living Copepods of the Great Lakes

Abstract An annotated checklist of the free-living copepods of the Laurentian Great Lakes is developed on the basis of published records. Synonymies are included for each species, relating, wherever possible, invalid names in the literature with currently recognized taxonomy. Twelve species of calanoids, six species of planktonic cyclopoids, nine species of benthic/ littoral cyclopoids, and fourteen species of harpacticoids have been reported from the Great Lakes. Ten of the calanoids and four of the cyclopoids are characteristic of limnetic waters. Three calanoids and two planktonic cyclopoids have been reported infrequently and are perhaps accidental occurrences. The composition of the planktonic copepod fauna in most subregions of the Great Lakes is well-known. In contrast, the sampling of benthic/littoral cyclopoids and harpacticoids has been so infrequent that their kinds, areas of occurrence, and relative abundances are still poorly understood.

A comparative study of contaminant levels in Long Island Sound

This paper uses results from the National Oceanic and Atmospheric Administration’s National Status and Trends Program (NS&T) to place the environmental quality of Long Island Sound in a broader perspective. It compares levels of contaminants in blue mussels from ten Long Island Sound sites and in sediments from seven Long Island Sound sites with concentrations in the same media at 87 and 221 other sites, respectively, where comparable samples were obtained. In sediments, the levels of both trace metals and organic contaminants tend to be relatively high for Long Island Sound sites. This is especially true for five of the twelve metals (silver, cadmium, copper, lead, and zinc) and for five of six categories of organic contaminants (total chlordane, low molecular weight polycyclic aromatic hydrocarbons (PAHs), high molecular weight PAHs, total polychlorinated biphenyls, and total dichlorodiphenyltrichloroethanes). In mussels, the organic contaminant categories exhibit relatively high levels, but this is not true for most of the metals. In fact, four of the metals—arsenic, mercury, selenium, and zinc—show evidence of relatively low levels in mussels from Long Island Sound compared to other NS&T locations.

The Estuarine Component of the Us E.P.A.'S Environmental Monitoring and Assessment Program

Abstract The US Environmental Protection Agencys Office of Research and Development has initiated the Environmental Monitoring and Assessment Program (EMAP) to monitor status and trends in the condition of the nations near coastal waters, forests, wetlands, agro-ecosystems, surface waters, deserts and rangelands. the programme is also intended to evaluate the effectiveness of Agency policies at protecting ecological resources occurring in these systems. Monitoring data collected for all ecosystems will be integrated for regional and national status and trends assessments. the near coastal component of EMAP consists of estuaries, coastal waters, and the Great Lakes. Near coastal ecosystems have been regionalized and classified, and an integrated sampling strategy has been developed. EPA and NOAA have agreed to coordinate and, to the extent possible, integrate the near coastal component of EMAP with the NOAA National Status and Trends Program. A demonstration project was conducted in estuaries of the mid-...

THE EFFECT OF TEMPERATURE ON REPRODUCTION OF CYCLOPS VERNALIS FISCHER (COPEPODA, CYCLOPOIDA)

[Cyclops vernalis Fischer ♀♀ wurden von der letzten Hautung an bis zu ihren Lebensende beobachtet bei Temperaturen von 15, 21, 26 und 31° C. Fur jedes Individuum wurde die Dauer des Erwachsenenstadiums und die Anzahl der entwickelten Eier festgestellt. Bei 31 °C lebt das Endstadium durchschnittlich 26 Tage und bei 14°C 74 Tage. Auch die Zeit bis zum ersten Gelege und die Intervalle dazwischen waren bei niedrigen Temperaturen langer. Bei 21 ° C war die Eiproduktion optimal. Die durchschnittliche Gelegegrosse variierte von 31 Eiern bei 31° C bis 47 Eiern bei 21 ° C und die totale Eierzahl von 124 pro ♀ bei 31° C zu 234 Eiern bei 21° C. Die durchschnittliche Zahl der Gelege hingegen variierte kaum bei verschiedenen Temperaturen. Ferner wurde der Temperatureinfluss auf die Entwicklungszeit der Eier und ihre Lebensfahigkeit untersucht. Die Entwicklungszeit ging von 28 std. bei 31°C bis zu 13 Tagen bei 5° C. Auf die Lebensfahigkeit der Eier hatte die Temperatur keinen Einfluss,, Cyclops vernalis Fischer ♀♀ wurden von der letzten Hautung an bis zu ihren Lebensende beobachtet bei Temperaturen von 15, 21, 26 und 31° C. Fur jedes Individuum wurde die Dauer des Erwachsenenstadiums und die Anzahl der entwickelten Eier festgestellt. Bei 31 °C lebt das Endstadium durchschnittlich 26 Tage und bei 14°C 74 Tage. Auch die Zeit bis zum ersten Gelege und die Intervalle dazwischen waren bei niedrigen Temperaturen langer. Bei 21 ° C war die Eiproduktion optimal. Die durchschnittliche Gelegegrosse variierte von 31 Eiern bei 31° C bis 47 Eiern bei 21 ° C und die totale Eierzahl von 124 pro ♀ bei 31° C zu 234 Eiern bei 21° C. Die durchschnittliche Zahl der Gelege hingegen variierte kaum bei verschiedenen Temperaturen. Ferner wurde der Temperatureinfluss auf die Entwicklungszeit der Eier und ihre Lebensfahigkeit untersucht. Die Entwicklungszeit ging von 28 std. bei 31°C bis zu 13 Tagen bei 5° C. Auf die Lebensfahigkeit der Eier hatte die Temperatur keinen Einfluss,]

The Present Status of Research on the Zooplankton and Zoobenthos of the Great Lakes

Abstract A brief evaluation of the present status of knowledge concerning the basic ecology of the zooplankton and zoobenthos of the Great Lakes is presented by considering (1) the species of invertebrates that occur in the Great Lakes, (2) how these species are distributed in space and time, and (3) the factors that cause the observed distributions. It is concluded that we are well along at describing what invertebrates occur in the lakes, but there are still major gaps in our knowledge. Regarding distribution, there is now a good data base for describing the distributions of a number of the most important species, but in most cases the results from separate surveys have not been pulled together to develop generalizations with broad application throughout the Great Lakes. Finally, understanding concerning the control of distributions of Great Lakes invertebrates is still at a rudimentary stage, even though such understanding is a basic requirement for evaluating natural and man-induced changes or potential changes in these ecosystems.