abstract The objectives of this chapter are to summarize our observations of fishes in Hudson River tributaries and to document the significance of tributaries to them. Currently alewife is the only anadromous fish that extensively uses Hudson River tributaries. Several potamodromous species depend on tributaries for reproduction (at least smallmouth bass and white sucker) or reproduce in several areas including tributaries (white perch). In many cases, the data available are not adequate to determine how significant tributary spawning is in these species. Young-of-year fishes present in tributary mouths are also abundant in other habitats in the tidal Hudson River, which is also true for those species considered resident in the tributary mouths. Too few tributaries have been examined thoroughly enough to determine whether tributaries are significant for either of these groups of fishes.

Introduction

The tidal Hudson River has at least seventy-nine small to large tributary streams in addition to the Upper Hudson and Mohawk Rivers, which enter the tidal Hudson at the Troy Dam, the upstream limit of tidal influence. There are also an unknown number of smaller, often ephemeral, streams that contribute water to the tidal Hudson River. These tributaries (other than the Upper Hudson/Mohawk) contribute about 20 percent of the freshwater input to the Hudson River (Cooper, Cantelmo, and Newton, 1988). Various researchers have considered these tributaries as sources of important materials such as carbon, sediments (Howarth et al., 1991; Howarth, Schneider, and Swaney, 1996; Swaney, Sherman, and Howarth, 1996), and contaminants (Hirschberg et al., 1996).

abstract Mathematical models are useful tools for quantifying primary production. The evolution of mathematical modeling of eutrophication toward the understanding and management of nutrients and primary production includes successively more complex and sophisticated mathematical formulations which account for the interactions between light, nutrients, and phytoplankton. Application of modern eutrophication models to the management of the Hudson River Estuary requires linkage among the New York/New Jersey (NY/NJ) Harbor Estuary, the New York Bight, and Long Island Sound. The development and application of the System-Wide Eutrophication Model (SWEM) is an example of how primary production in the Hudson River Estuary can be studied from both a cause and effect and a systemwide perspective. SWEM results show that primary productivity in the Lower Hudson River Estuary and contiguous waterways, with the exception of western Long Island Sound and portions of Raritan Bay, is controlled by the availability of light and residence time rather than nutrients. SWEM results also show that both nitrogen and carbon contribute to dissolved oxygen deficit but the relative importance of each is quite dependent upon specific location and the interrelationship of a number of physical, chemical, and biological variables. It is due to these complexities that mathematical modeling becomes an effective technique in understanding the process of primary production in the Lower Hudson.

Introduction

The purpose of this chapter is to describe how mathematical models may be applied to increase the understanding of primary production. The main points of this chapter include:

1. An overview of primary production in natural water systems;

2. […]

abstract This chapter uses data from a few representative sampling sites in the Hudson basin to understand variations in major ion concentrations, which are used as one simple proxy of gross drinking water quality. Other water supply issues, including potential implications of dissolved organic carbon concentrations on drinking water quality, are also discussed. The major ion content of surface waters is largely determined by precipitation chemistry, dry deposition from the atmosphere, chemical weathering of rock and soil minerals, and anthropogenic loadings, and then modified by biogeochemical reactions that take place within the system. (1) Based on data reported for West Point, New York by the National Atmospheric Deposition Program (NADP), precipitation chemistry in the Hudson River basin is similar to that in much of the northeastern United States. As a result of upwind and regional fossil fuel combustion, sulfate and nitrate are the most abundant anions and hydrogen is the most abundant cation (i.e., dilute solutions of sulfuric and nitric acids). Ammonium, chloride, and sodium have lower concentrations, with the latter two derived mostly from marine aerosols. Chloride appears to have an additional, nonmarine, source accounting for at least 25 percent of wet deposition of this ion at West Point. (2) Major element chemistry of surface waters in the Hudson River basin strongly reflects bedrock geology of tributary catchments. Adirondack and Catskill Mountain and Hudson Highland streams have low total dissolved solids (TDS) typical of ancient crystalline, metamorphic, or previously weathered coarse silicic sedimentary formations. In contrast, the significantly higher TDS of the Mohawk River reflect drainage from large areas of sedimentary rocks including limestones, carbonate-rich shales, and evaporite minerals.

abstract For nearly four centuries humans have been affecting Hudson River resources, with the most profound human influences occurring during the last 150 years. Economic issues have been at the root of most environmental management decisions. Problems and controversies, like dealing with New York City's sewerage, Westway and the Hudson River Power Case, have shaped both regional and national environmental policies. The current intricate matrix of governmental institutions, nongovernmental organizations, and multiple and multidisciplinary issues involved greatly complicates environmental management in the United States. New management structures have emerged to deal with problems that cross political and institutional boundaries, and for which no single entity has full responsibility to resolve. Successes in conquering regional problems have shared the same characteristics: the development of sound technical information to understand the problem and its potential solution; the formation of appropriate partnerships that include all appropriate decision makers; pressure from stakeholders and concerned individuals outside the management agencies for specific outcomes; the acquisition of funds appropriate to the task; and an institutional structure to implement the solution. There is a disconnect between the institutions that fund research and the management agencies that use the information that the funded research generates. With growing demands for watershed planning, habitat restoration, contaminant reduction, and biodiversity protection, agencies will require better understandings of ecosystem processes in order to formulate credible and predictive management strategies.

abstract The sediments of the Hudson River Estuary record chronologies of the history of sediment and contaminant accumulation. The distribution of natural and anthropogenic radionuclides in the sediments provides a means of deciphering the sediment chronology because the rates of supply and decay of the radionuclides are known. Radionuclides that are useful in this context include naturally occurring 234Th (Thorium), 7Be (Beryllium), and 210Pb (Lead), as well as anthropogenic 137Cs (Cesium), input from atmospheric testing of atomic weapons and in association with the use of nuclear power. Sediment accumulation in the Hudson, as in many other estuaries, is controlled by a dynamic equilibrium among the processes responsible for transporting sediment. This equilibrium can shift seasonally, moderated by river discharge, tidal mixing, and other natural forces, or be shifted by human activities such as dredging or pier construction. Sediment chronologies of Hudson cores determined from natural radionuclides show that coves, marginal areas, and the inner harbor are areas of enhanced accumulation. Short-term storage of sediment is evident off Manhattan following the spring freshet, but these high rates of sediment accumulation are not sustained on longer, decadal time scales. Sediment chronologies also help to interpret the sediment record of particle-associated contaminants in the context of temporal changes of contaminant input and accumulation. To fully realize this application, it is necessary to build a long-term database of cores for which chronologies have been determined. Key stations should be re-cored over time to document trends in contaminant accumulation.

abstract The course and character of the Hudson reflect its underlying geological structure and the modifications of Pleistocene glaciations. Radiating drainage out of the Adirondacks is transformed into a broad meandering pattern in its tidal reaches below Troy. The river's course then cuts through the Hudson Highlands in a fjord-like gorge. A broad curving path takes the river along the Triassic, Palisades Escarpment following the juncture with the older rocks of Manhattan. The bedrock foundation of the Hudson was established in three mountain-building episodes beginning over a billion years ago. Most recently, the entire region has been glaciated and the course of the Hudson takes it through relic beds of glacial lakes and several ice margin deposits of glacial sediment. After the deglaciation of the region, estuarine conditions were established in the Hudson beginning about 12,000 years ago. The Hudson briefly crosses the coastal plain breaching the Wisconsin terminal moraine at the Narrows. On the continental shelf, the course of the ancestral Hudson is marked by the Hudson Submarine Canyon.

Introduction

The source of the Hudson River was discovered in 1872 by the naturalist and surveyor, Verplanck Colvin. It is a pond on the western slope of Mt. Marcy, the highest peak in the Adirondacks at 1,629 m. Colvin, an ardent supporter of preserving the mountain forests and watershed, referred to the pond as ‘tear of the clouds’ (Schneider, 1997).

abstract The Hudson River Estuary has been polluted for many decades with organic contaminants including PCBs, dioxins/furans, PAHs, pesticides, and a variety of toxic metals, including cadmium and mercury. Most of these toxicants are poorly metabolized, highly persistent, bioaccumulative, and biomagnify in Hudson River populations, sometimes to record high levels. Many surveys have quantified tissue levels of these contaminants in resource species, but despite public concern and a need to evaluate toxicities for regulatory actions, few studies have directly addressed their biological impacts on Hudson River populations. With several notable exceptions, toxicant-induced perturbations are not frequently observed in Hudson River populations, even those for which high levels of exposure have been documented. This may have resulted from the ability of populations to acquire resistance to high levels of contaminants, either through genetic adaptations or compensatory physiological acclimation responses. While offering short-term benefits to impacted populations, resistance may be associated with evolutionary costs to populations and may compromise the viability of affected communities. Ideally, in the future, contaminant studies should focus on those species for which toxic alterations have been observed which may impact population viability, their levels of contamination should be quantified, and controlled laboratory experiments should be conducted to confirm that the contaminants of concern are able to induce these toxic manifestations in the affected taxon.

The Problem: Assessment of Toxicity of Hudson River-borne Pollutants

There is a need for government agencies to evaluate the toxic impacts of contaminants on the Hudson River (HR) biota to determine if damage to its populations has occurred and to guide remediation efforts.

abstract We examined the impacts of man-made structures, especially large piers, on fishes in the lower Hudson River, USA over a number of years. We used a multifaceted approach, and evaluated: 1) the distribution and abundance of fishes under piers, at pier edges, in pile fields, and in open water areas, 2) feeding and growth of young-of-the-year fishes (winter flounder, tautog, and Atlantic tomcod) under and around piers, and 3) availability of benthic prey for fishes under and adjacent to large piers. A review of our studies suggests that species diversity and species abundance were depressed under piers relative to nearby habitats. The only species that were routinely collected from under piers were those that do not appear to solely rely on the use of vision to forage (American eel, naked goby, Atlantic tomcod). Results from studies of the distribution of benthic invertebrate prey for fishes around piers suggest that prey abundances under piers are more than sufficient to support fish growth, however, results of directed growth studies indicate that feeding and growth rates of visually-feeding fish species (winter flounder, tautog) are negative under piers (that is, fish lose weight). It is not likely that factors associated with pier pilings, such as reduced flow or sedimentation, affect feeding, since studies of fish growth in pile fields (piers without the decking) indicate that fish grow well in that habitat. Rather, it appears that the decking associated with piers creates conditions of intense shading that impede foraging activities. We propose that under-pier areas, and potentially any areas that significantly reduce light penetration to depth in near shore areas, are poor habitats for fishes, and we urge careful consideration of shading effects prior to the construction, restoration, or renovation of over-water structures.

abstract Benthic animals (those that live in or on sediments or vegetation) are of key importance in the Hudson River ecosystem. They are the major source of food to the Hudson's fish and regulate the abundance and composition of phytoplankton in the river. Benthic animals probably are important in mixing sediments, an activity that may affect the movement and ultimate fate of toxins in the river, although this process is not well studied in the Hudson. The benthic animal community of the Hudson is diverse, containing several hundred species of worms, mollusks, crustaceans, insects, and other invertebrates. These animals represent a wide array of life histories, feeding types, distributions, and adaptations. Community structure and population density vary greatly from place to place in the Hudson, and are determined chiefly by salinity, the presence of rooted plants, and the nature of the sediment (hard vs. soft). Nevertheless, a great deal of site-to-site variation in benthic community structure in the Hudson and other large rivers is unexplained. Human activities (especially water pollution and alteration of the channel for navigation) probably had large effects on the benthic communities of the Hudson, but these effects have not been well documented. The recent invasion of the Hudson by the zebra mussel (Dreissena polymorpha) profoundly changed the benthic communities of the river, altering their composition and function in the ecosystem.

abstract Zooplankton in the Hudson River estuary include both freshwater and estuarine species and range in body lengths from microns to millimeters. Measurements of abundance and biomass as well as community rate processes indicate that zooplankton do not generally exert significant grazing pressure on phytoplankton. In addition, recycling of nutrients by zooplankton is not significant to primary producers because concentrations of dissolved nutrients are quite high in the Hudson and controlled by other processes. Zooplankton do provide an important linkage in the food web as they are key prey items for many young-of-year fish as well as fish that are primarily planktivorous throughout life. Long-term observations indicate many zooplankton populations undergo regular seasonal cycles in abundance, typically with increases during warm, low-flow periods of the year. The invasion of the zebra mussel into the Hudson had strong impacts on zooplankton in the freshwater section of the estuary. Microzooplankton such as rotifers declined dramatically. Cladocerans also declined in annual average abundance between pre- and post-zebra mussel periods when the effects of wet and dry years are taken into account. Zebra mussels, however, had little effect on larger zooplankton. Regulation of zooplankton appears to be a function of physical forces that affect population residence times as well as food and predators. Evidence for food limitation is mixed. Some species benefit from food supplements in experimental trials, but the reduction of phytoplankton biomass in association with the zebra mussel invasion had no effect on cladoceran egg production. There are a variety of potential predators, and calculations indicate fish exert high rates of mortality on zooplankton.

abstract In this chapter, we examine the impacts on human health of persistent environmental pollutants found in the watershed of the Hudson River, with particular focus on the potential of these contaminants to cause injury to the developing human brain. Polychlorinated biphenyls (PCBs), organochlorine pesticides, and mercury have been shown to be widespread in bottom sediments as well as in edible species of fish, shellfish, and crustaceans in the lower Hudson River and the New York Harbor complex. Interview surveys of anglers have documented that local residents consume fish, shellfish, and crustaceans from the lower Hudson, despite longstanding advisories by health officials. Poor people and people of color are the most likely to consume locally caught fish. In a recent pilot survey of levels of PCBs, organochlorine pesticides, and mercury in the blood and hair of local anglers, we documented that anglers who consume fish from the lower Hudson River and New York Harbor have higher levels than anglers who consume no locally caught fish. A positive exposure-response relationship was seen in these findings, with the highest levels of PCBs, pesticides, and mercury observed in those anglers who ate the most fish. Within the local fish-eating population, pregnant women and women of childbearing age are the groups at greatest risk. Intrauterine and early postnatal exposures to PCBs and mercury, at levels similar to the levels found in Hudson River aquatic species, have been shown in carefully conducted prospective epidemiological studies of human infants and children to cause loss of intelligence and alteration of behavior.

abstract Successful management of underwater lands requires detailed knowledge of the terrain and the interrelationships between landscape and habitat characteristics. While optical techniques can be used where the water is shallow or clear, other techniques are needed where the water is deeper or where optical transmission is limited by water clarity. Marine geophysical techniques provide quantitative measures of the nature of the estuary floor that can provide constraints on the distribution and movement of contaminated sediments as well as the nature of benthic habitats. The Benthic Mapping Program, supported by the Hudson River Estuary Program of the New York State Department of Environmental Conservation (NYSDEC) and the Hudson River Action Project, is being conducted in the Hudson River to characterize the river bed from the Verrazano Narrows in New York Harbor to the Federal Dam at Troy, New York. The study is using a range of acoustic and sampling techniques to gain new information on the river bed. The first phase of the Benthic Mapping Program, which occurred from 1998 to 2000, focused on four areas (about 40 river miles; 65 km). The products from the study have been incorporated into a GIS data management system for NYSDEC (see http://benthic.info for the DEC Benthic Mapper web site, an online version of the GIS database). This effort, supplemented by studies of benthic fauna and bathymetric change, is being continued under NYSDEC support for the remainder of the Hudson River. The second phase of the program worked in four areas in 2001 and 2002 (about 35 river miles; 57 km) and we completed the study by working in three areas in 2003 (about 66 river miles; 121 km).

FOR THIRTY YEARS or more, I have been urging people to grow the plants in their gardens that come from comparable soils and climates. For thirty years and more, I have been wrong, for these are the plants that are most likely to leap the garden wall, to get ‘out of bounds’, as they are now doing at an accelerating and frightening rate.

A change that has been taking place since the European invasion of the continent has gained momentum quite massively in the last few decades. That change is the introduction of exotic plants, animals and pathogens that make a takeover bid in their new environment. In the words of Alfred Crosby, European immigrants did not arrive alone in the new lands: they were accompanied by ‘a grunting, lowing, neighing, crowing, chirping, snarling, buzzing, self-replicating and world-altering avalanche’. As for the animals, so for the plants. Early in the last century, especially in semi-arid South Australia, the cultivation of wheat was attempted in country that was far too dry, in the mistaken belief that ‘Rain follows the plough’. In reality, weeds follow the plough. Wild oats (Avena spp.) arrived with the first wheat seed, and is now to be found wherever there is disturbed ground in southern Australia, smothering what is left of the indigenous plant cover, and ready to burn with the first cigarette butt in summer.