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John F. Elder

Publications and source records attributed to John F. Elder.

At least 19 recordsLinked to original sources
USGS2009

Dynamics in phosphorus retention in wetlands upstream of Delavan Lake, Wisconsin

A phosphorus budget was constructed for Delavan Lake Inlet, a perennial riverine wetland with submersed and floating aquatic vegetation in southeastern Wisconsin, to better understand the phosphorus dynamics in natural wetlands and the role of wetlands in lake-rehabilitation efforts. During the growing season, the inlet served as a net source of phosphorus , primarily due to the release of phosphorus from the sediments. More phosphorus was released from the sediments of the inlet (600 kg) than was input from the upstream watershed (460 kg). This release was caused by high pH associated with high photosynthetic activity. During the remainder of the year, the inlet served as a net sink for phosphorus , retaining 6% of die phosphorus input from the watershed. Over the entire year, this wetland was a net source of over 500 kg of phosphorus to downstream Delavan Lake. A constructed riverine wetland upstream of Delavan Lake Inlet demonstrated a similar periodic release of phosphorus . However, in this case, the summer release of phosphorus was less than that trapped during the remainder of the year. The constructed wetland served as a net sink for approximately 20% of the input phosphorus on an annual time scale. The role of existing and constructed wetlands as phosphorus traps is complex. Wetlands can act as a source or a sink for phosphorus depending on the ambient conditions in die wetland . Howa wetland fits into a rehabilitation plan depends upon its net retention efficiency and the importance of the periodic releases of phosphorus to downstream waters.

Wisconsin↗
USGS2008

Nitrogen and phosphorus speciation and flux in a large Florida river wetland System

Hydrologic measurements and analyses of various nitrogen and phosphorus species were made on the Apalachicola River system in northern Florida in 1979 and 1980. Annual outflows of total nitrogen (TN) and total phosphorus (TP) were not substantially different from annual inflows. However, there was significant net import of ammonia and soluble reactive phosphorus and net export of some particulate and organic species. The TN: TP ratio ranged from 12 to 15, but the specific ratio of dissolved inorganic nitrogen: soluble reactive phosphorus was much higher (up to 40) and increased in a downstream direction; this contributed to a phosphorus-limiting situation in Apalachicola estuary. Processes within the flood plain ecosystem accounted for much of the release of organic and particulate species and retention of inorganic species. This flood plain function is probably critical for maintaining a nutrient pool in the estuary which supports secondary productivity and a detrital-based food web.

Florida↗
USGS2007

Distribution and grain-size partitioning of metals in bovfom sediments of an experimentally acidified Wisconsin lake

A study of concentrations and distribution of major and trace elements in surficial bottom sediments of Little Rock Lake in northern Wisconsin included examination of spatial variation and grain-size effects. No significant differences with respect to metal distribution in sediments were observed between the two basins of the lake, despite the experimental acidification of one of the basins from pH 6.1 to 4.6. The concentrations of most elements in the lake sediments were generally similar to soil concentrations in the area and were well below sediment quality criteria. Two exceptions were lead and zinc, whose concentrations in July 1990 exceeded the criteria of 50 μg/g and 100 μg/g, respectively, in both littoral and pelagic sediments. Concentrations of some elements, particularly Cu, Pb, and Zn, increased along transects from nearshore to midlake, following a similar gradient of sedimentary organic carbon. In contrast, Mn, Fe, and alkali/alkaline-earth elements were at maximum concentrations in nearshore sediments. These elements are less likely to partition to organic particles, and their distribution is more dependent on mineralogical composition, grain size, and other factors. Element concentrations varied among different sediment grain-size fractions, although a simple inverse relation to grain size was not observed. Fe, Mn, Pb, and Zn were more concentrated in a grain-size range 20–60 tm than in either the very fine or the coarse fractions, possibly because of the aggregation of smaller particles cemented together by organic and Fe/Mn hydrous-oxide coatings.

Wisconsin↗
USGS2003

Nutrient, trace-element, and ecological history of Musky Bay, Lac Courte Oreilles, Wisconsin, as inferred from sediment cores

Sediment cores were collected from Musky Bay, Lac Courte Oreilles, and from surrounding areas in 1999 and 2001 to determine whether the water quality of Musky Bay has declined during the last 100 years or more as a result of human activity, specifically cottage development and cranberry farming. Selected cores were analyzed for sedimentation rates, nutrients, minor and trace elements, biogenic silica, diatom assemblages, and pollen over the past several decades. Two cranberry bogs constructed along Musky Bay in 1939 and the early 1950s were substantially expanded between 1950?62 and between 1980?98. Cottage development on Musky Bay has occurred at a steady rate since about 1930, although currently housing density on Musky Bay is one-third to one-half the housing density surrounding three other Lac Courte Oreilles bays. Sedimentation rates were reconstructed for a core from Musky Bay by use of three lead radioisotope models and the cesium-137 profile. The historical average mass and linear sedimentation rates for Musky Bay are 0.023 grams per square centimeter per year and 0.84 centimeters per year, respectively, for the period of about 1936?90. There is also limited evidence that sedimentation rates may have increased after the mid-1990s. Historical changes in input of organic carbon, nitrogen, phosphorus, and sulfur to Musky Bay could not be directly identified from concentration profiles of these elements because of the potential for postdepositional migration and recycling. Minor- and trace-element profiles from the Musky Bay core possibly reflect historical changes in the input of clastic material over time, as well as potential changes in atmospheric deposition inputs. The input of clastic material to the bay increased slightly after European settlement and possibly in the 1930s through 1950s. Concentrations of copper in the Musky Bay core increased steadily through the early to mid-1900s until about 1980 and appear to reflect inputs from atmospheric deposition. Aluminum- normalized concentrations of calcium, copper, nickel, and zinc increased in the Musky Bay core in the mid-1990s. However, concentrations of these elements in surficial sediment from Musky Bay were similar to concentrations in other Lac Courte Oreilles bays, nearby lakes, and soils and were below probable effects concentrations for aquatic life. Biogenic-silica, diatom-community, and pollen profiles indicate that Musky Bay has become more eutrophic since about 1940 with the onset of cottage development and cranberry farming. The water quality of the bay has especially degraded during the last 25 years with increased growth of aquatic plants and the onset of a floating algal mat during the last decade. Biogenic silica data indicate that diatom production has consistently increased since the 1930s. Diatom assemblage profiles indicate a shift from low-nutrient species to higher-nutrient species during the 1940s and that aquatic plants reached their present density and/or composition during the 1970s. The diatom Fragilaria capucina (indicative of algal mat) greatly increased during the mid-1990s. Pollen data indicate that milfoil, which often becomes more common with elevated nutrients, became more widespread after 1920. The pollen data also indicate that wild rice was present in the eastern end of Musky Bay during the late 1800s and the early 1900s but disappeared after about 1920, probably because of water-level changes more so than eutrophication.

Wisconsin↗
USGS2000

Sources and yields of dissolved carbon in northern Wisconsin stream catchments with differing amounts of Peatland

In five tributary streams (four inflowing and one outflowing) of 1600-ha Trout Lake in northern Wisconsin, USA, we examined factors that can affect the magnitude of stream flow and transport of dissolved organic and inorganic carbon (DOC and DIC) through the streams to the lake. One catchment, the Allequash Creek basin, was investigated in more detail to describe the dynamics of carbon flow and to identify potential carbon sources. Stream flows and carbon loads showed little or no relation to surface-water catchment area. They were more closely related to ground-water watershed area because ground-water discharge, from both local and regional sources, is a major contributor to the hydrologic budgets of these catchments. An important factor in determining carbon influx to the stream is the area of peatland in the catchment. Peatland porewaters contain DOC concentrations up to 40 mg 1 −1 and are a significant potential carbon source. Ground-water discharge and lateral flow through peat are the suspected mechanisms for transport of that carbon to the streams. Carbon and nitrogen isotopes suggested that the sources of DOC in Allequash Creek above Allequash Lake were wetland vegetation and peat and that the sources below Allequash Lake were filamentous algae and wild rice. Catchments with high proportions of peatland, including the Allequash Creek catchment, tended to have elevated DOC loads in outflowing stream water. Respiration and carbon mineralization in lakes within the system tend to produce low DOC and low DOC/DIC in lake outflows, especially at Trout Lake. In Allequash Lake, however, the shallow peat island and vegetation-filled west end were sources of DOC. Despite the vast carbon reservoir in the peatlands, carbon yields were very low in these catchments. Maximum yields were on the order of 2.5 g m −2 y −1 DOC and 5.5 g m −2 y −1 DIC. The small yields were attributable to low stream flows due to lack of significant overland runoff and very limited stream channel coverage of the total catchment area.

Wisconsin↗
USGS2000

Chemical composition of surficial sediment in Geneva Lake, Wisconsin

Intense recreational use of Geneva Lake and extensive residential and other development in its watershed (fig. 1) has created concern over a possible decline in water quality of the lake. Because of this concern, a collaborative effort between the U.S. Geological Survey (USGS), Wiscon- sin Department of Natural Resources (WDNR), and the Geneva Lake Environmental Agency was begun to document the present quality of the water and its sediments, to estimate the amount of nutrients (primarily phosphorus) coming into the lake, and to describe changes that have occurred in the lake over the past 200 years. In this fact sheet, we describe the quality of the surficial sediments of the lake.

Wisconsin↗
USGS1997

Retention of sediments and nutrients in Jackson Creek wetland near Delavan Lake, Wisconsin, 1993-95

Excessive inflow of sediment and nutrients has contributed to eutrophication of Delavan Lake in southeastern Wisconsin. A wetland restoration project at the mouth of the lake's principal inflowing stream system was implemented in 1992, primarily for the purpose of reducing sediment and nutrient loading to the lake. This function of the wetland system, which includes three retention ponds, was examined in a 32-month study (February 1993-September 1995) that included continuous monitoring of discharge of two inflowing streams and the wetland outflow, intermittent monitoring of discharge of a third inflowing stream, monthly and storm-runoff sampling to determine sediment and nutrient concentrations, and measurement of sediment accumulation in three constructed sediment retention ponds. Inflow and outflow loads of sediment and nutrients were computed from the discharge and concentration data. The wetland system consistently retained suspended sediments during the study period. Volumetric surveys of the ponds showed sediment accumulation each year, and during the 32 months, 46 percent of the inflow sediment load was retained in the wetland and the retention ponds. Retention of nutrients in the wetland system, however, was of lesser magnitude and much greater seasonal variability. Over time periods of one year or more, most nutrient forms were retained in the wetland system. Nutrient retention, relative to the 32-month inflow loads was: 19 percent of total phosphorus, 11 percent of dissolved orthophosphate, 8 percent of total ammonia plus organic nitrogen, and 0.4 percent of dissolved nitrite plus nitrate nitrogen. Of the nutrient forms measured, only dissolved ammonia, whose 32-month outflow from the wetland system was 22 percent greater than inflow, showed a long-term net release from the system. However, net releases over shorter time periods were commonly observed for all nutrients, and these occurred frequently during the growing season, suggesting probable availability to algal and macrophyte communities downstream. Awareness of the variability and complexity of the nutrient-trapping function of a wetland system can help maintain realistic expectations of the benefits of wetland restoration projects and can be valuable in developing more effective management practices.

Wisconsin↗
USGS1996

Sediment and nutrient trapping efficiency of a constructed wetland near Delavan Lake, Wisconsin, 1993-1995

Jackson Creek Wetland a 95-acre shallow prairie marsh containing three sediment retention ponds was constructed in 1992 to reduce sediment and nutrient in- flow to eutrophic Delavan Lake. The function of the wetland as a retention system for suspended sediments and nutrients (total and dissolved phosphorus, total ammonia plus organic nitrogen, dissolved ammonia, and nitrite plus nitrate nitrogen) was studied from February 1993 through September 1995. Input and output load computations were based on water flow (discharge) measurements and periodic sampling of suspended sediments and nutrients at the three inflowing streams and at the wetland outflow. Results of the study indicated consistent sediment retention throughout the year; at times, as much as 80 percent of the inflow load was retained in the wetland. Nutrient retention was generally of lesser magnitude and much more variable. Although the annual budgets confirm net retention for all nutrient forms except ammonia, data analysis over shorter time scales show that outflow loads actually can exceed inflow loads during the late spring and summer months the period of greatest likelihood of algal blooms in the lake. This result demonstrates that the nutrient-trapping function of the wetland is variable because of the complexity of the system. Awareness of such variability can help to maintain realistic expectations and effective management practices.

Wisconsin↗
USGS1992

Water, Energy, and Biogeochemical Budgets (WEBB) program: Data availability and research at the Northern Temperate Lakes site in north-central Wisconsin

More than three thousand kettle lakes, widely dispersed within a mixed temperate forest ecosystem, are predominant features of the Northern Highland area of north-central Wisconsin. A hydrological and biogeochemical investigation of seven of these lakes and their watershed area is currently in progress as part of the Water, Energy, and Biogeochemical Budgets (WEBB) program of the U.S. Geological Survey. The objectives of the overall WEBB program are to: (1) improve understanding of processes controlling water, energy, and biogeochemical fluxes in freshwater systems, the interactions among those processes, and their relations to climatic variables; and (2) improve the capability to predict freshwater, energy, and biogeochemical budgets over a range of spatial and temporal scales. The focus of the WEBB project in Wisconsin is hydrologic research in the Northern Temperate Lakes (NTL) area of the state. Based on the premise that an understanding of hydrologic and biogeochemical cycles in the watershed is predicated on a thorough understanding of the individual components that control the water flow, the project involves a detailed study of the hydrologic budget, including the roles of rainfall, streamflow, ground water, and flow in the unsaturated zone. It also involves investigation of ground-water/ surface-water interactions. The objectives of the Northern Temperate Lakes WEBB project are to: (1) describe processes controlling water and solute fluxes in the NTL watersheds; (2) examine interactions among those processes and their relations to climatic variables; and (3) improve the capability to predict changes in water and solute fluxes for a range of spatial and temporal scales. A variety of procedures will be used to address the objectives of the project including: installation of piezometers, lysimeters, stream-gaging sites, precipitation collectors, climate-monitoring instruments; analysis of transport of nutrients and other solutes through the system; analysis of changes in isotopic composition of water; and temperature profiling. The implementation of these procedures is described in this report. The NTL-WEBB study area includes seven lakes that are also the site of a Long-Term Ecological Research (LTER) project, sponsored by the National Science Foundation. This project incorporates diverse research investigations conducted by faculty and research associates of the University of Wisconsin-Madison. The research orientation of NTL-LTER is principally toward aquatic ecology and geochemistry of the lakes. The WEBB research plan, with its emphasis on hydrologic processes in the lake watersheds, is designed to complement and enhance the LTER work.

Wisconsin↗
USGS1991

Freshwater molluscs as indicators of bioavailability and toxicity of metals in surface-water systems

During the past several decades, studies from a variety of locations have demonstrated widespread occurrence of metals in surface waters at concentrations significantly higher than background levels. Elevated concentrations are not limited to certain water types or polluted areas; they appear in all types of systems and in all geographic areas. It is clear that metals enter the aquatic systems from diverse sources, both point and nonpoint, and they can be readily transported from one system to another. Transport routes include atmospheric, terrestrial, subterranean, aquatic, and biological pathways (Elder 1988; Salomons and Forstner 1984).

Book chapter↗
USGS1990

Applicability of ambient toxicity testing to national or regional water-quality assessment

Comprehensive assessment of the quality of natural waters requires a multifaceted approach. Descriptions of existing conditions may be achieved by various kinds of chemical and hydrologic analyses, whereas information about the effects of such conditions on living organisms depends on biological monitoring. Toxicity testing is one type of biological monitoring that can be used to identify possible effects of toxic contaminants. Based on experimentation designed to monitor responses of organisms to environmental stresses, toxicity testing may have diverse purposes in water-quality assessments. These purposes may include identification of areas that warrant further study because of poor water quality or unusual ecological features, verification of other types of monitoring, or assessment of contaminant effects on aquatic communities. Toxicity-test results are most effective when used as a complement to chemical analyses, hydrologic measurements, and other biological monitoring. However, all toxicity-testing procedures have certain limitations that must be considered in developing the methodology and applications of toxicity testing in any large-scale water-quality-assessment program. A wide variety of toxicity-test methods have been developed to fulfill the needs of diverse applications. The methods differ primarily in the selections made relative to four characteristics: (1) test species, (2) endpoint (acute or chronic), (3) test-enclosure type, and (4) test substance (toxicant) that functions as the environmental stress. Toxicity-test approaches vary in their capacity to meet the needs of large-scale assessments of existing water quality. Ambient testing, whereby the test organism is exposed to naturally occurring substances that contain toxicant mixtures in an organic or inorganic matrix, is more likely to meet these needs than are procedures that call for exposure of the test organisms to known concentrations of a single toxicant. However, meaningful interpretation of ambient test results depends on the existence of accompanying chemical analysis of the ambient media. The ambient test substance may be water or sediments. Sediment tests have had limited application, but they are useful because most toxicants tend to accumulate in sediments and many test species either inhabit the sediments or are in frequent contact with them. Biochemical testing methods, which have been developing rapidly in recent years, are likely to be among the most useful procedures for large-scale water-quality assessments. They are relatively rapid and simple, and more. importantly, they focus on biochemical changes that are the initial responses of virtually all organisms to environmental stimuli. Most species are sensitive to relatively few toxicants, and their sensitivities vary as conditions change. Therefore, each test method has particular uses and limitations, and no single test has universal applicability. One of the most informative approaches to toxicity testing is to combine biochemical tests with other test methods in a 'battery of tests' that is diversified enough to characterize different types of toxicants and different trophic levels. However, such an approach can be costly, and if not carefully designed, it may not yield enough additional information to warrant the additional cost. The application of toxicity tests to large-scale water-quality assessments is hampered by a number of difficulties. Toxicity tests often are not sensitive enough to enable detection of most contaminant problems in the natural environment. Furthermore, because sensitivities among different species and test conditions can be highly variable, conclusions about the toxicant problems of an ecosystem are strongly dependent on the test procedure used. In addition, the experimental systems used in toxicity tests cannot replicate the complexity or variability of natural conditions, and positive test results cannot identify the source or nature of

Circular↗
USGS1988

Metal biogeochemistry in surface-water systems; a review of principles and concepts

Metals are ubiquitous in natural surface-water systems, both as dissolved constituents and as particulate constituents. Although concentrations of many metals are generally very low (hence the common term 'trace metals'), their effects on the water quality and the biota of surfacewater systems are likely to be substantial. Biogeochemical partitioning of metals results in a diversity of forms, including hydrated or 'free' ions, colloids, precipitates, adsorbed phases, and various coordination complexes with dissolved organic and inorganic ligands. Much research has been dedicated to answering questions about the complexities of metal behavior and effects in aquatic systems. Voluminous literature on the subject has been produced. This paper synthesizes the findings of aquatic metal studies and describes some general concepts that emerge from such a synthesis. Emphasis is on sources, occurrence, partitioning, transport, and biological interactions of metals in freshwater systems of North America. Biological interactions, in this case, refer to bioavailability, effects of metals on ecological characteristics and functions of aquatic systems, and roles of biota in controlling metal partitioning. This discussion is devoted primarily to the elements aluminum, arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury, nickel, and zinc and secondarily to cobalt, molybdenum, selenium, silver, and vanadium. Sources of these elements are both natural and anthropogenic. Significant anthropogenic sources are atmospheric deposition, discharges of municipal and industrial wastes, mine drainage, and urban and agricultural runoff. Biogeochemical partitioning of metals is controlled by various characteristics of the water and sediments in which the metals are found. Among the most important controlling factors are pH, oxidation-reduction potential, hydrologic features, sediment grain size, and the existence and nature of clay minerals, organic matter, and hydrous oxides of manganese and iron. Partitioning is also controlled by biological processes that provide mechanisms for detoxification of metals and for enhanced uptake of nutritive metals. Partitioning is important largely because availability to biota is highly variable among different phases. Hence, accumulation in biological tissues and toxicity of an element are dependent not only on total concentration of the element but also on the factors that control partitioning.

Circular↗
USGS1988

Hydrology and ecology of the Apalachicola River, Florida : a summary of the river quality assessment

During 1979-81, the U.S. Geological Survey conducted a large-scale study of the Apalachicola River in northwest Florida, the largest and one of the most economically important rivers in the State. Termed the Apalachicola River Quality Assessment, the study emphasized interrelations among hydrodynamics, the flood-plain forest, and the nutrient-detritus flow through the river system to the estuary. This report summarizes major findings of the study. Data on accumulation of toxic substances in sediments and benthic organisms in the river were also collected. Because of the multiple uses of the Apalachicola River system, there are many difficult management decisions. The river is a waterway for shipping; hence there is an economic incentive for modification to facilitate movement of barge traffic. Such modifications include the proposed construction of dams, levees, bend easings, and training dikes; ditching and draining in the flood plain; and dredging and snagging in the river channel. The river is also recognized as an important supplier of detritus, nutrients, and freshwater to the Apalachicola Bay, which maintains an economically important shellfish industry. The importance of this input to the bay creates an incentive to keep the river basin in a natural state. Other values, such as timber harvesting, recreation, sport hunting, nature appreciation, and wildlife habitat, add even more to the difficulty of selecting management strategies. Water and nutrient budgets based on data collected during the river assessment study indicate the relative importance of various inputs and outflows in the system. Waterflow is controlled primarily by rainfall in upstream watersheds and is not greatly affected by local precipitation, ground-water exchanges, or evapotranspiration in the basin. On an annual basis, the total nutrient inflow to the system is nearly equal in quantity to total outflow, but there is a difference between inflow and outflow in the chemical and physical forms in which the nutrients are carried. The flood plain tends to be a net importer of soluble inorganic nutrients and a net exporter of particulate organic material. Analysis of long-term records shows that dam construction in the upstream watersheds and at the Apalachicola headwaters has had little effect on the total annual waterflow but has probably suppressed low-flow extremes. Other effects include riverbed degradation and channelization which have to do with alteration of the habitat for aquatic biota and changes in flood-plain vegetation. Whatever management decisions are made should take into account the impact on the natural flooding cycle. Flooding is crucial to the present flood-plain plant community and to the production, decomposition, and transport of organic material from that community. Permanent, substantial changes in the natural flooding cycle would be likely to induce concomitant changes in the flood-plain environment and in the nutrient and detritus yield to the estuary.

Water Supply Paper↗
USGS1984

Accumulation of trace elements, pesticides, and polychlorinated biphenyls in sediments and the clam Corbicula manilensis of the Apalachicola River, Florida

A survey of trace element and synthetic organic compound concentrations in bottom materials was conducted on the Apalachicola River in northwest Florida in 1979–80 as part of the Apalachicola River Quality Assessment. Substances analyzed included trace elements (predominantly heavy metals), organochlorine insecticides, organophosphorus insecticides, chlorinated phenoxy-acid herbicides, and poly chlorinated biphenyls (PCBs). Three kinds of materials were surveyed: finegrained sediments, whole-body tissue of the Asiatic clam Corbicula manilensis , and bottom-load organic detritus. No hazardous levels of any of the substances were found. Concentrations in the finegrained sediments and clams were generally at least ten times lower than maximum limits considered safe for biota of aquatic systems. A comparison of trace-substance data from the Apalachicola River with data from Lake Seminole (upstream) and Apalachicola Bay (downstream) showed lower concentrations in riverine clams. Sediment concentrations in all parts of the system were comparable. Most trace substances in the Apalachicola River enter the river from the upstream part of the basin (the Chattahoochee and Flint Rivers in Georgia and Alabama) and from nonpoint sources throughout the basin. There are no major point discharges along the Apalachicola. Trend analysis was limited by the scope of the study, but did not reveal any spatial or temporal trends in concentrations of any of the substances analyzed. Concentrations of organic compounds and most metals in Corbicula manilensis did not correlate with those in sediments.

Florida↗
USGS1984

Nutrient and detritus transport in the Apalachicola River, Florida

The Apalachicola River in northwest Florida flows 172 kilometers southward from Jim Woodruff Dam near the Florida-Georgia border to Apalachicola Bay on the Gulf of Mexico. The basin is composed of two 3,100-squarekilometer subbasins, the Chipola and the Apalachicola. The Apalachicola subbasin includes a 454-square-kilometer bottom-land hardwood flood plain that is relatively undeveloped. The flood plain contains more than 1,500 trees per hectare that annually produce approximately 800 metric tons of litter fall per square kilometer. Spring floods of March and April 1980 carried 35,000 metric tons of particulate organic carbon derived from litter fall into Apalachicola Bay. The estuarine food web is predominantly detrital based and represents an important commercial source of oyster, shrimp, blue crab, and various species of fish. The water budget of the Apalachicola basin is heavily dominated by streamflow. For a 1-year period in 1979-80, 28.6 cubic kilometers of water flowed past the Sumatra gage on the lower river. Eighty percent of this volume flowed into the upper river near Chattahoochee, Fla., and 11 percent was contributed by its major tributary, the Chipola River. Contributions from ground water and overland runoff were less than 10 percent. Streamflow increases downstream were accompanied by equivalent increases in nitrogen and phosphorus transport. The nutrients were released to the river by the flood-plain vegetation, but also were subject to recycling. The increase in the amount of organic carbon transport downstream was greater than streamflow increases. The flood plain is an important source of organic carbon, especially in detrital form. Several methods for measurement of detritus in the river and flood plain were developed and tested. The detritus data from the flood plain added semiquantitative evidence for transport of detritus from the flood plain to the river flow, probably accounting for most of the coarse particulate organic material carried by the river. During the 1-year period of investigation, June 3, 1979, through June 2, 1980, 2.1 ? 10 5 metric tons of organic carbon were transported from the river basin to the bay. Nitrogen and phosphorus transport during the same period amounted to 2.2 ? 10 4 and 1.7 ? 10 3 metric tons, respectively. On an areal basis, it was calculated that the flood plain contributed 70 grams of organic carbon per square meter per year, 0.4 gram of nitrogen per square meter per year, and 0.5 gram of phosphorus per square meter per year. The flood plain acts as a source of detrital carbon, but for the solutes, nutrient release is approximately balanced by nutrient retention.

Water Supply Paper↗
USGS1982

Production and decomposition of forest litter fall on the Apalachicola River flood plain, Florida

Measurements of litter fall (leaves and other particulate organic material) and leaf decomposition were made on the bottom-land hardwood swamp of the Apalachicola River flood plain in 1979-80. Litter fall was collected monthly from nets located in 16 study plots. The plots represented five forest types in the swamp and levee areas of the Apalachicola River flood plain. Forty-three species of trees, vines, and other plants contributed to the total litter fall, but over 90 percent of the leaf material originated from 12 species. Nonleaf material comprised 42 percent of the total litter fall. Average litter fall was determined to be 800 grams per square meter per year, resulting in an annual deposition of 360,000 metric tons of organic material in the 454-square-kilometer flood plain. The levee communities have lower tree biomass but higher tree diversity than swamp communities. The levee vegetation, with lower tree biomass, produces slightly more litter fall per ground surface area than the swamp vegetation. The swamps are dominated by three genera: tupelo (Nyssa), cypress (Taxodium), and ash (Fraxinus). These genera account for over 50 percent of the total leaf fall in the flood plain but they are the least productive, on a weight-per-biomass basis, of any of the 12 major leaf producers. Decomposition rates of leaves from five common flood-plain tree species were measured using a standard leaf-bag technique. Leaf decomposition was highly species-dependent. Tupelo (Nyssa spp.) and sweetgum (Liquidambar styraciflua) leaves decomposed completely in 6 months when flooded by river water. Leaves of baldcypress (Taxodium distichum) and diamond-leaf oak (Quercus laurifolia) were much more resistant. Water hickory (Carya aquatica) leaves showed intermediate decomposition rates. Decomposition of all species was greatly reduced in dry environments. Carbon and biomass loss rates from the leaves were nearly linear over a 6-month period, but nitrogen and phosphorus leaching was nearly complete within 1 month. Much of the organic substance may be recycled in the forest ecosystem, but annual flooding of the river provides an important mechanism for mobilization of the litter-fall products.

Florida↗
USGS1982

Production and decomposition of forest litter fall on the Apalachicola River flood plain, Florida: Chapter B, Apalachicola River quality assessment

Measurements of litter fall (leaves and other particulate organic material) and leaf decomposition were made on the bottom-land hardwood swamp of the Apalachicola River flood plain in 1979-80. Litter fall was collected monthly from nets located in 16 study plots. The plots represented five forest types in the swamp and levee areas of the Apalachicola River flood plain. Forty-three species of trees, vines, and other plants contributed to the total litter fall, but more than 90 percent of the leaf material originated from 12 species. Nonleaf material made up 42 percent of the total litter fall. Average litter fall was determined to be 800 grams per square meter per year, resulting in an annual deposition of 3.6 ? 105 metric tons of organic material in the 454-square-kilometer flood plain. The levee communities have less tree biomass but greater tree diversity than do swamp communities. The levee vegetation, containing less tree biomass, produces slightly more litter fall per unit of ground surface area than does the swamp vegetation. The swamps are dominated by three genera: tupelo (Nyssa), cypress (Taxodium) and ash (Fraxinus). These genera account for more than 50 percent of the total leaf fall in the flood plain, but they are the least productive, on a weight-perbiomass basis, of any of the 12 major leaf producers. Decomposition rates of leaves from five common floodplain tree species were measured using a standard leaf-bag technique. Leaf decomposition was highly species dependent. Tupelo (Nyssa spp.) and sweetgum (Liquidambar styraciflua) leaves decomposed completely in 6 months when flooded by river water. Leaves of baldcypress (Taxodium distichum) and diamond-leaf oak (Quercus laurifolia) were much more resistant. Water hickory (Carya aquatica) leaves showed intermediate decomposition rates. Decomposition of all species was greatly reduced in dry environments. Carbon and biomass loss rates from the leaves were nearly linear over a 6-month period, but nitrogen and phosphorus leaching was nearly complete within 1 month. Much of the organic substance may be recycled in the forest ecosystem, but annual flooding of the river provides an important mechanism for mobilization of the litter-fall products.

Water Supply Paper↗