Blackstone River Research Articles

Spatiotemporal dynamics of landscape pattern and hydrologic process in watershed systems

Land use change is influenced by spatial and temporal factors that interact with watershed resources. Modeling these changes is critical to evaluate emerging land use patterns and to predict variation in water quantity and quality. The objective of this study is to model the nature and emergence of spatial patterns in land use and water resource impacts using a spatially explicit and dynamic landscape simulation. Temporal changes are predicted using a probabilistic Markovian process and spatial interaction through cellular automation. The MCMC (Monte Carlo Markov Chain) analysis with cellular automation is linked to hydrologic equations to simulate landscape patterns and processes. The spatiotemporal watershed dynamics (SWD) model is applied to a subwatershed in the Blackstone River watershed of Massachusetts to predict potential land use changes and expected runoff and sediment loading. Changes in watershed land use and water resources are evaluated over 100 years at a yearly time step. Results show high potential for rapid urbanization that could result in lowering of groundwater recharge and increased storm water peaks. The watershed faces potential decreases in agricultural and forest area that affect open space and pervious cover of the watershed system. Water quality deteriorated due to increased runoff which can also impact stream morphology. While overland erosion decreased, instream erosion increased from increased runoff from urban areas. Use of urban best management practices (BMPs) in sensitive locations, preventive strategies, and long-term conservation planning will be useful in sustaining the watershed system.

Variability of E. coli density and sources in an urban watershed

The objective of this study was to characterize the variability of Escherichia coli density and sources in an urban watershed, particularly to focus on the influences of weather and land use. E. coli as a microbial indicator was measured at fourteen sites in four wet weather events and four dry weather conditions in the upper Blackstone River watershed. The sources of E. coli were identified by ribotyping. The results showed that wet weather led to sharp increases of E. coli densities. Interestingly, an intense storm of short duration led to a higher E. coli density than a moderate storm of long duration (p<0.01). The ribotyping patterns revealed microbial sources were mainly attributed to humans and wildlife, but varied in different weather conditions and were associated with the patterns of land use. Human sources accounted for 24.43% in wet weather but only 9.09% in dry weather. In addition, human sources were more frequently observed in residential zones (>30% of the total sources), while wildlife sources were dominant in open land and forest zones (54%). The findings provide useful information for developing optimal management strategies aimed at reducing the level of pathogens in urban watersheds.

Evaluating U.S. National Heritage Areas: Theory, Methods, and Application

Like many governmental actors in recent decades, the U.S. National Park Service (NPS) has operated increasingly through partnerships with other state and federal agencies, non-governmental organizations (NGOs), community groups, and private sector corporations. Perhaps the most salient example of this trend toward partnerships is the rapid growth and development of national heritage areas (NHAs). Since the first NHA received congressional designation in 1984, NHAs have become an increasingly popular strategy for protecting and managing landscapes. To date, congressional designation has been granted to 49 NHAs, making them one of the fastest growing initiatives involving the NPS. Despite this growth, no prior research has examined the efficacy or effectiveness of the NHA model. This article introduces the NHA concept, while reviewing the literature on evaluation research and its application to protected area management. We then offer an NHA program theory model for evaluating NHAs. The model was developed using a theory-based, process evaluation approach, along with 90 qualitative interviews conducted at three study sites: Blackstone River Valley National Heritage Corridor, MA-RI (BLAC); Delaware and Lehigh National Heritage Corridor, PA (DELE); and Cane River National Heritage Area, LA (CANE). We conclude by discussing the key challenges and implications associated with developing a long-term research agenda for evaluating NHAs.

Riders of the Imagination: George Monteiro on Stephen Crane Studies

Riders of the ImaginationGeorge Monteiro on Stephen Crane Studies Robert M. Dowling (bio) Scholar and poet George Monteiro, Professor Emeritus of English and of Portuguese and Brazilian Studies at Brown University, was first introduced to Stephen Crane as a subject in 1954 while studying for his master’s degree at Columbia University. “I can recall sitting, one gray autumn afternoon, in Columbia University’s Butler Library,” Monteiro told me, “reading John Berryman’s book on Crane, not because it was assigned in any of my courses, but because of my interest in Ernest Hemingway,” who had cited Crane as one of his most important forerunners.1 Since that first afternoon in the Morningside Heights neighborhood of upper Manhattan devouring Berryman’s foundational 1950 biography Stephen Crane, Monteiro has authored over sixty articles, notes, and reviews directly pertaining to Crane—an average of more than one a year for over half a century—along with scores of other articles, monographs, translations, and edited collections in English and Portuguese on writers as diverse as Nathaniel Hawthorne, Herman Melville, William Dean Howells, Henry James, Elizabeth Bishop, Emily Dickinson, Robert Frost, Ernest Hemingway, Luís Vaz de Camões, and Fernando Pessoa. Monteiro’s prodigious body of Crane scholarship culminated in Stephen Crane’s Blue Badge of Courage (2000) and offered an ideal foundation for the edited volume, Stephen Crane: The Contemporary Reviews (2009). No urban dweller by background, Monteiro was born and raised in the small village of Valley Falls in the township of Cumberland, Rhode Island. Alice R. Clemente, a close friend of his since elementary school, describes their hometown as “one of those nineteenth/early twentieth-century mill villages nestled on the banks of the Blackstone River in a region historians now call ‘the cradle of American industry’” (148). New York City was thus a revelation for the 22-year-old Portuguese-New Englander and recent Brown University graduate, who notes that “New York was definable—as [End Page 37] it might still be, though more ironically—as ‘accessibility to experience’ (Marianne Moore’s words).” “Having come from a small university,” he continues, “I found Columbia enormous, especially by the day’s standards. All day long and well into the evening its twenty-five thousand students (it seemed) crossed and criss-crossed the heart of the campus at West 116th street between Broadway and Amsterdam Avenue.” Perhaps most important for the emergent scholar, Monteiro’s English professors at Columbia loomed large as the undisputed titans of twentieth-century literary criticism. “All I had to do was pay attention and I could legitimately consider myself to be a (minor) party to big literary doings. In Philosophy Hall new students paused to read the names on the office doors.” The “names” in question included F. W. Dupee, William York Tindall, Eric Bentley, Lionel Trilling, Richard Chase, Lewis Leary, Suzanne K. Nobbe, Roger Sherman Loomis, and Marjorie Hope Nicholson (then head of the English Department), among others. Monteiro never took a class with Lionel Trilling, the department’s brightest star, but Trilling’s influence on him has always been immense: “When I found it difficult to begin writing a paper, I would then (and for years afterwards) read in The Liberal Imagination on any topic whatsoever until I felt inspired enough to go back to my own writing, usually on a topic foreign to Trilling’s concerns” (“Notes on Columbia”). Indeed, in 1955 Monteiro was writing his thesis, under the direction of Daniel G. Hoffman, on a topic no doubt “foreign to Trilling’s concerns,” Monteiro adds, entitled “Sports in the Writings of Ernest Hemingway.” Hoffman, now a legendary poet and critic, was then a Ph.D. candidate working on a dissertation examining Crane’s poetry, a study based largely on new acquisitions at Columbia’s library that he soon after expanded into his seminal book The Poetry of Stephen Crane (1957). Columbia’s Rare Book and Manuscript Library had just obtained, auspiciously for Monteiro and Hoffman, a raft of primary Crane material that still stands, along with collections at Syracuse University and the University of Virginia, as one of the most important repositories for Crane scholarship. After reading Berryman’s biography, Monteiro...

Review: John H. Chafee Blackstone River Valley National Heritage Corridor

Review: John H. Chafee Blackstone River Valley National Heritage Corridor

Review of Hydrodynamics and Water Quality: Modeling Rivers, Lakes, and Estuaries by Zhen-Gang JiHydrodynamics and Water Quality: Modeling Rivers, Lakes, and EstuariesWiley Interscience, John Wiley &amp; Sons, Inc.978-0-470-13543-3

Management of surface water systems, including rivers, reservoirs, lakes, wetlands, and estuaries, requires technical tools that must be based on physical, chemical, biological, and social sciences. Some of these tools entail numerical hydrodynamic and water quality models, made possible these days by everincreasing computing prowess. This book attempts to describe physical, chemical, and biological concepts underlying these models. To that end, the book aims at providing an integrated treatment of hydrodynamics, sediment transport and processes, toxic fate and transport, water quality, and eutrophication in surface water systems. The emphasis in the book is on principles, basic processes, mathematical descriptions, and practical applications via case studies. Justifiably, it avoids long mathematical derivations. The book also presents case studies to illustrate the implementation of basic concepts and theories and technical approaches based thereon into mathematical models, as well as application of these models to address practical environmental and water resources problems. The subject matter of the book is logically divided into 10 chapters and three appendices. Chapter 1 provides an overview and develops the context for the material to be described in the book. Chapter 2 provides basic concepts and principles of hydrodynamics. Starting with a description of hydrodynamic processes, it goes on to discuss governing equations and their approximations in one-dimensional, two-dimensional and three-dimensional Cartesian coordinates. Equations in curvilinear coordinates are presented next, followed by a discussion of initial and boundary conditions. Then temperature and heat fluxes are presented. This discussion is integrated in the following section on hydrodynamic modeling, with case studies of Lake Ockeechobee and the St. Lucie Estuary and Indian River Lagoon. These case studies are very helpful to understand hydrodynamics and its practical application. Sediment transport is discussed in Chapter 3. Providing an overview, including sediment properties, problems associated with sediment, and sediment processes, it discusses sediment transport equations for both cohesive and noncohesive sediments, as well as wind waves and their impact on sediment transport. The chapter presents two case studies one on wind wave modeling and the other on sediment transport modeling in Lake Ockeechobee. The third case study is on sediment transport modeling for Blackstone River. These case studies clearly show how to set up a model, define initial and boundary conditions, prepare data

Fate and Transport Modeling of Potential Pathogens: The Contribution From Sediments1

Abstract: Escherichia coli was used as a bacterial tracer for the development, calibration, and validation of a watershed scale fate and transport model to be extended to a suite of reference pathogens (Cryptosporidium, Giardia, Campylobacter, E. coli O157:H7). E. coli densities in water and sediments from the Blackstone River Watershed, Massachusetts, were measured at three sites for a total of five wet weather events and three dry weather events covering three seasons. The confirmed E. coli strains were identified by ribotyping for tracking the sources of E. coli and for determining the association of downstream E. coli isolates with isolates from upstream sediments. A large number of downstream samples were associated with upstream sediment sources of E. coli. E. coli densities ranged from 71 to 6,401 MPN/100 ml in water samples and from 2 to 335 MPN/g in sediments. Pearson correlation analysis revealed significant correlations between E. coli and total coliforms in water (r = 0.777, p &lt; 0.01) and sediments (r = 0.728, p &lt; 0.01). In addition, E. coli concentrations in water were weakly correlated with sediment particle size and sediment concentrations (r = 0.298, p &lt; 0.01). A hydrologic model, WATFLOOD/SPL9, was used to predict the temporal and spatial variation of E. coli in the Blackstone River. The rapid rise of stream E. coli densities was more accurately predicted by the model with the inclusion of sediment resuspension, thus demonstrating the importance of the process.

Watershed-Scale Tradeoffs in Water Quantity and Quality Attributes for Conservation Policy

Information on tradeoffs among water quantity and quality attributes at a watershed scale is important in developing effective watershed conservation policies. Assessment of these multiattribute tradeoffs, a focus of this study, is often a low priority in policy design. A combination of simulation modeling and statistical assessment was used to evaluate the significance of relationships among runoff, sediment, nitrate, and phosphorus loading in 115 subwatersheds of the Blackstone River Watershed in southern New England. We observed high variability in rates of runoff, nitrate, phosphorus, and sediment loading among subwatersheds. Results of the regression analysis indicate a high correlation between nitrate and surface runoff, emphasizing the importance of stormwater management in mitigating nutrient loads. A significant relationship exists between mineral phosphorus and sediment yield in watersheds that could inform strategies to mitigate eutrophication problems in phosphorus-limited systems such as some inland water bodies. The tradeoff analysis proposed can be used in policy design and to assess the implications of various policies to address multiple pollutants.

Paleovegetation and Paleoclimatic Changes in the Yukon at 6 ka BP

The most recent paleoenvironmental change to affect the Yukon centres around 6.0 ka. In the forested southern Yukon, black spruce (Picea mariana) and green alder (Alnus crispa) expanded their populations at most sites between 6.5 and 6.0 ka. Even in the semi-arid region of SW Yukon these species increased their populations, although slightly later at 5.5 ka. These vegetation changes in the south imply cooler and wetter growing seasons, i.e. more mesic conditions. In the region of the upper Blackstone River of central Yukon, the modern vegetation consists of shrub tundra with scattered groves of white spruce (Picea glauca) and even fewer black spruce. Open forests of predominantly white spruce occupied the region as early as 9.5 ka, but between 6.5 and 6.0 ka white spruce declined as black spruce became the dominant tree, coincidentally with an increase in green alder. By 5.0 ka the vegetation had acquired its modern composition. As in the south, these changes imply cooling. Less evidence is available on the expansion of alder and black spruce in the northern Yukon. Both species increased in forested areas (forest-tundra) at 6.0 ka. These changes again imply cooling. Because both black spruce and green alder were present in Yukon well before 6 ka, these vegetation changes cannot be ascribed to migration lags.

Making ‘Smart’ Use of a Sewer in Worcester, Massachusetts: A Cautionary Note on Smart Growth as an Economic Development Policy

This paper provides a conceptual critique of ‘smart growth’, an increasingly popular urban redevelopment strategy, as an economic development policy. It seeks to do this in two ways. First, an argument is made for how the smart growth movement is linked to more broad discourses of economic development. Second, through an urban political ecology analysis, it is suggested that smart growth, through the lens of the environment, reveals an uneven distribution of benefits among people affected by smart growth developments. This is because smart growth itself is embedded in a particular historical construction of environment. To explore these issues the author focuses on the Blackstone River and Canal, the site of a new smart growth development, in New England's third largest city of Worcester, Massachusetts. The Blackstone case presented here is exemplary in that it so clearly reflects the evolution of regional capitalist development, including the current one. Moreover, these periods, once past, are not relegated to the dustbins of history; rather they inform the next round of development. The case study below will thus reveal how these histories have, circuitously, played a role in the rationalization for the redevelopment of the canal as a smart growth project as well as elucidate the implications for the winners and losers of smart growth. The paper concludes with some thoughts on how we might, in practical terms, unlock the progressive potential of this development paradigm.

Northern Range Extension of the Pygmy Shrew, &lt;em&gt;Sorex hoyi&lt;/em&gt;, in the Yukon

A Pygmy Shrew, Sorex hoyi, was captured in a pitfall trap on the Blackstone River (65°04.6'N, 138°10.8'W) in central Yukon. This represents a northern range extension of about 110 km for S. hoyi in the Yukon.

Beauty &amp; Convenience: Architecture and Order in the New Republic (review)

Beauty & Convenience: Architecture and Order in the New Republic. By Nora Pat Small. (Knoxville: University of Tennessee Press, 2003. Pp. xxiv, 155. Illustrations, maps. Cloth, $29.95.)Nora Pat Small's short book, derived from her 1994 doctoral dissertation, addresses changes in architecture and landscape between 1790 and 1840, along with the intellectual debates and economic developments that influenced them. Rather than explore these themes on a national or regional basis, Small offers a community-based study of the town of Sutton in the Blackstone River Valley of central Massachusetts. Despite the tight focus, Small has much to work with, rioting that the people of Sutton reordered houses, barns, and fields in accordance with newly popular and widespread notions of beauty and convenience; they created commercial and social town centers where none had existed before; they dammed their rivers and streams and built textile mills and machine shops containing water-powered machinery and in the process these citizens of the early republic adapted old building to new uses, and even created new forms (xiii). Furthermore, the characteristics of Sutton's architectural and landscape evolution were representative of the wider American experience, thus giving the specificity of Small's subject area a larger meaning and interest for scholars interested in architecture, landscape, and related questions in material culture. Small ends her study around 1840, a logical cutoff date because architectural entered a new phase, as represented by such innovations as the widespread appearance of Picturesque architecture (whether Italianate, Gothic, or some other romantic form), which rejected the simplicity of the earlier Classical Revival style for a new set of values.Postrevolutionary New Englanders, especially those with at least middling aspirations, rebuilt much of their environment to take advantage of changing agricultural production, new industrial opportunities, and evolving perspectives on housing and self-identity. For instance, the two-story-with-ell Classical Revival house (inspired partly by the pattern books of individuals such as Asher Benjamin) came to dominate the rural domestic preferences in Small's study area in far larger numbers than before 1783, when modest, single-story homes had made up a greater percentage of the housing stock. Another iconic development of the period was the New England barn, which fluoresced in the 1820s. Conveniently aligned to the dwelling house and with a distinctive layout in which the drive paralleled the roof ridge, this barn form could accommodate more animals and larger crops with greater convenience than its predecessors.One of the more interesting discussions in the book examines the pronouncements of period reformers, whose views of how rural dwellers should design their homes clashed with the people who built and lived in them. …

Federal leverage attracts private investment at US heritage sites: A case study

This case study examines why people are returning to the Blackstone Valley, America’s industrial birthplace. Beginning in 1790, with cotton manufacturing, the Valley became the place to achieve the ‘American Dream’. By the 1940s, industry was leaving. The Valley went into economic freefall, people moved away, and mill villages decayed. In 1986, the National Park Service, with special legislation, and the Valley’s historic resources, began to tell the story about this special landscape. Using education, the Blackstone River is cleaner, historic properties are being thoughtfully restored, and visitor numbers are growing. Private investment in the Valley is now 15 times the National Park Service investment.

Late Quaternary glaciation in the Northern Ogilvie Mountains: revised correlations and implications for the stratigraphic record

New geomorphic, paleolimnological, and radiocarbon data suggest that a terminal moraine complex in the Northern Ogilvie Mountains, Yukon Territory, Canada, may represent the McConnell Glaciation (Late Wisconsinan), rather than the Reid Glaciation (marine isotope Stage 8; Illinoian) as previously thought. Relict fluvial channels on the surface of the moraine and analysis of a suite of lake sediment cores from Chapman Lake, a closed-basin kettle on the surface of the moraine, suggest that flow from the Blackstone River passed over the moraine and through the lake until ca. 12 500 BP, at which time the Blackstone River was captured by the East Blackstone River, diverting flow from the lake. Subsequent incision by the Blackstone River has left its base level more than 10 m below the level of Chapman Lake. Perched former outlets from Chapman Lake indicate that this incision must postdate stream capture. Because the Chapman Lake moraine is a topographic barrier across the Blackstone River valley, incision must have occurred shortly after deposition of the moraine, suggesting that the landscape surrounding Chapman Lake is substantially younger than previously thought. Additional radiocarbon dates also suggest that kettle subsidence at Chapman Lake was ongoing during the early Holocene and that North Fork Pass moraine, 15 km upvalley from the Chapman Lake moraine, may have been formed during the Late Glacial rather than the McConnell Glaciation.

Sediment and Metals Modeling in Shallow River

It is a challenge to apply coupled hydrodynamic, sediment process, and contaminant fate and transport models to the studies of surface water systems. So far, there are few published modeling studies on sediment and metal transport in rivers that simulate storm events on an hourly basis and use comprehensive data sets for model input and model calibration. The United States Environmental Protection Agency (USEPA) in 1997 emphasized the need for credible modeling tools that can be used to quantitatively evaluate the impacts of point sources, nonpoint sources, and internal transport processes in 1D/2D/3D environments. A 1D and time-dependent hydrodynamic, sediment, and toxic model, within the framework of the 3D Environmental Fluid Dynamics Code (EFDC), has been developed and applied to Blackstone River, Mass. The Blackstone River Initiative (USEPA) in 1996, a multiyear and multimillion-dollar project, provided the most comprehensive surveys on water quality, sediment, and heavy metals in the river, and served as the primary data set for this study. The model simulates three storm events successfully. The river flow rates are well calculated both in amplitude and in phase. The sediment transport and resuspension processes are depicted satisfactorily. The concentrations of sediment and five metals (cadmium, chromium, copper, nickel, and lead) during the three storm events are also simulated very well. Numerical analyses are conducted to clarify the impacts of contaminant sources and sediment resuspension processes on the river. While point sources are important to sediment contamination in the river, other sources, including nonpoint sources from watershed and bed resuspension, were found to contribute significantly to the sediment and metals in the river. Point sources alone cannot account for the total metals in the river. The model presented in this paper can be a useful tool for studying sediment and metals transport in shallow rivers and for water resource management.

Aquifer response to stream-stage and recharge variations. II. Convolution method and applications

In this second of two papers, analytical step-response functions, developed in the companion paper for several cases of transient hydraulic interaction between a fully penetrating stream and a confined, leaky, or water-table aquifer, are used in the convolution integral to calculate aquifer heads, streambank seepage rates, and bank storage that occur in response to stream-stage fluctuations and basinwide recharge or evapotranspiration. Two computer programs developed on the basis of these step-response functions and the convolution integral are applied to the analysis of hydraulic interaction of two alluvial stream–aquifer systems in the northeastern and central United States. These applications demonstrate the utility of the analytical functions and computer programs for estimating aquifer and streambank hydraulic properties, recharge rates, streambank seepage rates, and bank storage. Analysis of the water-table aquifer adjacent to the Blackstone River in Massachusetts suggests that the very shallow depth of water table and associated thin unsaturated zone at the site cause the aquifer to behave like a confined aquifer (negligible specific yield). This finding is consistent with previous studies that have shown that the effective specific yield of an unconfined aquifer approaches zero when the capillary fringe, where sediment pores are saturated by tension, extends to land surface. Under this condition, the aquifer's response is determined by elastic storage only. Estimates of horizontal and vertical hydraulic conductivity, specific yield, specific storage, and recharge for a water-table aquifer adjacent to the Cedar River in eastern Iowa, determined by the use of analytical methods, are in close agreement with those estimated by use of a more complex, multilayer numerical model of the aquifer. Streambank leakance of the semipervious streambank materials also was estimated for the site. The streambank-leakance parameter may be considered to be a general (or lumped) parameter that accounts not only for the resistance of flow at the river–aquifer boundary, but also for the effects of partial penetration of the river and other near-stream flow phenomena not included in the theoretical development of the step-response functions.

Dissolved oxygen modeling of the Blackstone River (northeastern United States)

A dissolved oxygen model, QUAL2E, has been calibrated and validated to the Blackstone River, using the data collected in 1991 for the Blackstone River Initiative — Dry Weather Study. Physical representation of the river is accomplished using the data from previous studies. Flow profiles have been developed using the average daily flows of the three permanent United States Geological Survey (USGS) gaging stations and five wastewater treatment plants on the Blackstone River. These flow profiles have been verified by the success of the model to simulate a conservative parameter, chloride and independent flow measurements. The calibration and validation of the model for dissolved oxygen involved a stepwise approach to simulate each source and sink of dissolved oxygen. This has been accomplished by progressively defining atmospheric reaeration, oxygen depletion due to carbonaceous biochemical oxidation demand, nitrification, sediment oxygen demand and algal photosynthesis and respiration. The success of the model can also be judged by the ability of the model to represent the system under different conditions. During additional validation with data sets from 1980, the model was successful in predicting conditions prior to a previous waste load allocation for the largest point source. Statistical tests of the model results and the observed data have been performed for the 1991 surveys with a median relative error of approximately 10%. A brief assessment of the 7Q10 flows indicates violations of the dissolved oxygen criteria of 5.0 mg/l occurring downstream of the Woonsocket wastewater treatment plant. Minor violations occur in Massachusetts upstream of four impoundments.

Coal rank, distribution, and coalbed methane potential of the Lower Cretaceous Luscar Group, Bow River to Blackstone River, central Alberta Foothills: F. M. Dawson & W. D. Kalkreuth, Bulletin — Geological Survey of Canada, 473, 1994, 52 pp, 8 maps

Coal rank, distribution, and coalbed methane potential of the Lower Cretaceous Luscar Group, Bow River to Blackstone River, central Alberta Foothills: F. M. Dawson & W. D. Kalkreuth, Bulletin — Geological Survey of Canada, 473, 1994, 52 pp, 8 maps

A water-quality history of the Blackstone River, Massachusetts, USA: implications for Central and Eastern European Rivers

The Blackstone River is a relatively small river that drains the area around Worcester, Massachusetts, one of first industrialized cities in the United States. Until the 1970s, the river was highly polluted by industrial and municipal wastewaters--not unlike the current situation in degraded rivers in areas of Central and Eastern Europe (CEE). Today, the Blackstone enjoys considerably improved water quality as the result of two historical processes: continuing investment and improvement in municipal wastewater treatment in response to increasingly stringent U.S. federal water-quality laws, and the control or elimination of industrial discharges. A key factor in the river's restoration was the early development of and continued adherence to a comprehensive basin water-quality plan. A similar planning process is recommended for CEE countries. Nonetheless, achieving acceptable water quality in the Blackstone was a slow process, requiring decades of intensive improvement in wastewater treatment. A similarly slow process can be anticipated in the CEE countries unless cost-effective interim improvements in wastewater treatment are sought.

Rates of Nitrification along an Estuarine Gradient in Narragansett Bay

Rates of pelagic nitrification, measured using N-Serve-sensitive [14C]bicarbonate uptake, varied by as much as an order-of-magnitude among three sites along the salinity gradient of Narragansett Bay (Rhode Island, United States). Rates were always higher at the Providence River estuary site (0.04–11.2 μmol N I−1 d−1) than at either the lower Narragansett Bay site (0.02–0.98 μmol N I−1d−1) or the freshwater Blackstone River site (0.04–1.7 μmol N I−1d−1). Although temperature was the most important variable regulating the annual cycle of nitrification, ammonium concentrations were most likely responsible for the large differences in rates among the three sites in summer. At the levels found in this estuarine system, salinity and concentrations of oxygen or total suspended matter did not appear to have a direct measurable effect on nitrification and pH did only occasionally. Nitrification played an important role in the nitrogen cycle at all three sites. In Narragansett Bay, nitrification contributed 55% of the NO2 − and NO3 − entering annually, and was the major source during spring and summer. Water from offshore was the only other large source of NO2 − and NO3 −, contributing 34%. High summer rates of nitrification could support much of the phytoplankton uptake of NO2 − and NO3 −. In the Providence River estuary, the largest annual input of NO2 − and NO3 − was from rivers (54%), although nitrification (28%) and water from lower portions of the bay (11%) also made large contributions. Again, nitrification was most important in the summer. The high rates of nitrification in the Providence River estuary during summer were also likely to be important in terms of oxygen demand, and the production of nitric and nitrous oxides. In the Blackstone River, NO2 − and NO3 − concentrations increased as the river flowed through Rhode Island, and nitrification was a possible source.