• A Basin-Wide Survey of Coastal Wetlands of the Laurentian Great Lakes: Development and Comparison of Water Quality Indices

      Harrison, Anna M.; Reisinger, Alexander J.; Cooper, Matthew J.; Brady, Valerie J.; Siborowski, Jan J. H.; O'Reilly, Katherine E.; Ruetz, Carl R.; Wilcox, Douglas A.; Uzarski, Donald G.; Central Michigan University; et al. (8/5/2019)
      Coastal wetlands of the Laurentian Great Lakes are vital habitats for biota of ecological and economic importance. These habitats are susceptible to water quality impairments driven by runoff from the landscape due to their location along the shoreline. Monitoring of the overall status of biotic and abiotic conditions of coastal wetlands within the Great Lakes has been ongoing for over a decade. Here, we utilize measurements of aquatic physicochemical and land cover variables from 877 vegetation zones in 511 coastal wetland sites spanning the US and Canadian shorelines of the entire Great Lakes basin. Our objective is to develop water quality indices based on physicochemical measures (Chem-Rank), land use/land cover (LULC-Rank), and their combined effects (Sum-Rank and Simplified Sum-Rank), for both vegetation zones and wetland sites.We found that water quality differed among wetland vegetation types and among Great Lakes regions, corroborating previous findings that human land use alters coastal wetland water quality. Future monitoring can use these straightforward, easy-to-calculate indices to assess the abiotic condition of aquatic habitats. Our data support the need for management efforts focused on reducing nutrient and pollution loads that stem from human activities, particularly in the developed southern portions of the Great Lakes basin.
    • A Chronosequence of Aquatic Macrophyte Communities in Dune Ponds.

      Wilcox, Douglas A.; Simonin, Howard A.; New York State Department of Environmental Conservation; The College at Brockport (1/1/1987)
      Differences in macrophyte community composition in a chronosequence of spatially separated dune ponds near the south shore of Lake Michigan were examined and related to environmental variables. Five ponds from each of five pond rows were sampled. In each pond, the cover of each plant species and water and sediment depth were sampled using a stratified random design. Radiocarbon dates were obtained from selected ponds. Ordination of the vegetation data by detrended correspondence analysis revealed similarities in the plant communities of ponds in the same row and community differences between ponds in different rows. Younger ponds (< 300 years) were dominated by Chara spp. and Najas flexilis, middle-age ponds (2100 years) by Myriophyllum spp. and Nymphaea tuberosa, and older ponds (3000 years) by Typha angustifolia. Distribution of macrophyte communities was most closely correlated with water depth, which generally decreased with increasing age of the pond row. Some sediment chemistry differences were found between pond rows, but there were no significant differences in water chemistry. Although a linear succession pattern is suggested, we think that anthropogenic disturbance played a major role in determining the vegetation differences observed. Thus, a chronosequence of spatially separated ponds can provide valuable information on hydrarch succession, but it may be misleading and actually represent succession affected by disturbance history.
    • A Model For Assessing Interdisciplinary Approaches to Wetland Research

      Wilcox, Douglas A.; The College at Brockport (1/1/1987)
      An interdisciplinary approach to research in wetlands is necessary to avoid incorrect extrapolations and projections about broad wetland functions based on limited knowledge. The values of several lesser-used disciplines or fields of study are often overlooked and therefore not incorporated into study designs. To address this problem, a model was developed that relates ten ecological and environmental science disciplines to each other (geohydrology, surface water hydrology, water chemistry, soil/sediment chemistry, stratigraphy/sedimentology, paleoecology, plant ecology, animal ecology, remote sensing, and seedbank studies). A matrix and compartmentalized model cross-identify each discipline as a research tool and as a type of study for which a given tool can be used in data collection. Use of the model is demonstrated by assessing the research approach utilized in the study of three wetland systems (shallow dune ponds, bog, fen) at Indiana Dunes National Lakeshore and the study of the pocosin wetlands as presented in a comprehensive volume on that subject.
    • A Paleoecological Test of a Classical Hydrosere in the Lake Michigan Dunes

      Jackson, Stephen T.; Futyma, Richard P.; Wilcox, Douglas A.; The College at Brockport (8/1/1988)
      Aquatic vegetation varies along a chronosequence of dune ponds at Miller Woods, Indiana Dunes National Lakeshore. Submersed and floating-leaved macrophytes dominate the vegetation of the youngest ponds. Older ponds contain mixed assemblages of submersed, floating-leaved, and emergent plant taxa. The oldest ponds are dominated by emergent plants, especially Typha angustifolia. We conducted paleoecological studies at one of the oldest ponds to test the hypothesis that the modern vegetational array along the pond chronosequence represents a hydrarch successional sequence. Macrofossil stratigraphy of the 3000-yr-old pond indicates no significant changes in pond vegetation following early colonization until < 150 BP. Pond vegetation before 150 BP consisted of a diverse assemblage of submersed, floating-leaved, and emergent macrophyte taxa. Pollen and macrofossil data indicate a major, rapid vegetational change at < 150 BP, evidently in response to local human disturbance. Pollen data reveal that the extensive Typha stands in the older ponds have developed recently, following postsettlement disturbance. Modern vegetational differences along the chronosequence reflect differential effects of disturbance rather than autogenic hydrarch succession. This study illustrates a major pitfall in inferring successional trends from spatial sequences of vegetation.
    • A Sault-outlet-referenced mid- to late-Holocene paleohydrograph for Lake Superior constructed from strandplains of beach ridges

      Johnson, John W.; Thompson, Todd A.; Lepper, K.; Wilcox, Douglas A.; Forman, S. L.; Johnston, John W.; Argyilan, Erin P.; Baedke, Steve J.; Indiana University; Indiana University Northwest; et al. (10/1/2012)
      The most detailed Lake Superior paleohydrograph relative to the current outlet near Sault Ste. Marie, Ontario–Michigan, was constructed from four strandplains of beach ridges. This provides a history of water-level, glacial isostatic adjustment (GIA), and the active outlet prior to monitoring and regulation. Four relative paleohydrographs that are offset and subparallel owing to differences in GIA were produced from 321 basal foreshore elevations and 56 optically stimulated luminescence ages. Subtracting modeled elevations in defined millennial lake phases between relative paleohydrographs and similarity between an inferred Sault Ste. Marie (hereinafter, Sault) paleohydrograph and data near the zero isobase corroborates rates of GIA derived from water-level gauges. A change in trend in the Sault paleohydrograph is related to the final separation of Lake Superior from Lakes Michigan and Huron and is the youngest age reported at 1060 +/- 100 years. A near-horizontal trend in the Sault paleohydrograph for the past millennium has an intercept that is close to the historical average for Lake Superior. A consistently linear trend from about 2 to 1 ka suggests a relatively stable outlet similar to the past millennium, but a decreasing trend from 3 to 1 ka suggests an outlet other than the Sault. Although intercept data beyond the last millennium are similar in elevation to the reported bedrock sill near Chicago (Hansel et al. 1985), we argue that the Port–Huron outlet was the active outlet during this time and the inferred paleohydrograph of Baedke and Thompson (2000) requires reevaluation.
    • A water-budget approach to restoring a sedge fen affected by diking and ditching

      Wilcox, Douglas A.; Sweat, Michael J.; Carlson, Martha L.; Kowalski, Kurt P.; The College at Brockport; U.S. Geological Survey (6/1/2005)
      A vast, ground-water-supported sedge fen in the Upper Peninsula of Michigan, USA was ditched in the early 1900 s in a failed attempt to promote agriculture. Dikes were later constructed to impound seasonal sheet surface flows for waterfowl management. The US Fish and Wildlife Service, which now manages the wetland as part of Seney National Wildlife Refuge, sought to redirect water flows from impounded C-3 Pool to reduce erosion in downstream Walsh Ditch, reduce ground-water losses into the ditch, and restore sheet flows of surface water to the peatland. A water budget was developed for C-3 Pool, which serves as the central receiving and distribution body for water in the affected wetland. Surface-water inflows and outflows were measured in associated ditches and natural creeks, ground-water flows were estimated using a network of wells and piezometers, and precipitation and evaporation/evapotranspiration components were estimated using local meteorological data. Water budgets for the 1999 springtime peak flow period and the 1999 water year were used to estimate required releases of water from C-3 Pool via outlets other than Walsh Ditch and to guide other restoration activities. Refuge managers subsequently used these results to guide restoration efforts, including construction of earthen dams in Walsh Ditch upslope from the pool to stop surface flow, installation of new water-control structures to redirect surface water to sheet flow and natural creek channels, planning seasonal releases from C-3 Pool to avoid erosion in natural channels, stopping flow in downslope Walsh Ditch to reduce erosion, and using constructed earthen dams and natural beaver dams to flood the ditch channel below C-3 Pool. Interactions between ground water and surface water are critical for maintaining ecosystem processes in many wetlands, and management actions directed at restoring either ground- or surface-water flow patterns often affect both of these components of the water budget. This approach could thus prove useful in guiding restoration efforts in many hydrologically altered and managed wetlands worldwide.
    • Acres vs. Outcome: Criteria for Funding Wetland Restoration

      Wilcox, Douglas A.; The College at Brockport (3/1/2012)
      This article argues that the metrics used for awarding wetlands restoration funding should be broadened. Innovative, experimentally based restoration proposals that could change the way we conduct restoration projects should be included in options for requests for proposals.
    • Advancing the Science of Microbial Symbiosis to Support Invasive Species Management: A Case Study on Phragmites in the Great Lakes

      Kowalski, Kurt P.; Bacon, Charles; Bickford, Wesley; Braun, Heather; Clay, Keith; Leduc-Lapierre, Michele; Lillard, Elizabeth; McCormick, Melissa K.; Nelson, Eric; Torres, Monica; et al. (2/19/2015)
      A growing body of literature supports microbial symbiosis as a foundational principle for the competitive success of invasive plant species.Further exploration of the relationships between invasive species and their associated microbiomes, as well as the interactions with the microbiomes of native species, can lead to key new insights into invasive success and potentially new and effective control approaches. In this manuscript, we review microbial relationships with plants, outline steps necessary to develop invasive species control strategies that are based on those relationships, and use the invasive plant species Phragmites australis (common reed)as an example of how development of microbial-based control strategies can be enhanced using a collective impact approach. The proposed science agenda, developed by the Collaborative for Microbial Symbiosis and Phragmites Management, contains a foundation of sequential steps and mutually-reinforcing tasks to guide the development of microbial-based control strategies for Phragmites and other invasive species. Just as the science of plant-microbial symbiosis can be transferred for use in other invasive species, so too can the model of collective impact be applied to other avenues of research and management.
    • Age, Growth, Relative Abundance, and Scuba Capture of a New or Recovering Spawning Population of Lake Sturgeon in the Lower Niagara River, New York

      Hughes, Thomas C.; Lowie, Christopher E.; Haynes, James M.; The College at Brockport; U.S. Fish and Wildlife Service (8/29/2005)
      The objective of our study was to collect age, growth, and catch-per-unit-effort information from a new or recovering population of lake sturgeon Acipenser fulvescens in the lower Niagara River, New York. From July 1998 through August 2000, we captured 67 lake sturgeon by use of gill nets, baited setlines, and scuba diving. Active capture by scuba divers (1.50 fish/ h) was much more effective than passive capture with gill nets (0.07 fish/h) and setlines (0.06 fish/h). Eggs of Chinook salmon Oncorhynchus tshawytscha were more effective as setline bait than were alewives Alosa pseudoharengus, but neither bait differed in effectiveness from rainbow smelt Osmerus mordax. Ages of captured lake sturgeon ranged from 1 to 23 years; 47 of the 61 aged fish were younger than age 10. Strong relationships were found between weight, W, and length, L (W = 0.0000005 L3.5564: R2 = 0.977) and between L and age (L = 394.05.log e[age] + 248.77; R2 = 0.878). The lake sturgeon population in the lower Niagara River is probably small relative to its historic abundance. This naturally reproducing population should remain listed as threatened by New York State, and commercial and recreational fisheries should remain closed so that the population can rebuild adult numbers and reproductive potential.
    • Altered Ecosystem Nitrogen Dynamics as a Consequence of Land Cover Change in Tallgrass Prairie

      Norris, Mark D.; Blair, John M.; Johnson, Loretta C.; The College at Brockport (10/1/2007)
      ABSTRACT.-Inre cent decades, substantial areas of North American tallgrass prairie have been lost to the establishment and expansion of woodlands and forests, including those dominated by eastern redcedar (Juniperus virginiana). This shift in dominant plant life form, from C4 grasses to coniferous trees, may be accompanied by changes in productivity, standing stocks of biomass and nutrients and biogeochemical cycles. The goal of this study was to quantify and compare major pools and fluxes of nitrogen in recently established (5 80 y) redcedar forests and adjacent native grasslands. Three former grassland sites in the Flint Hills region of Kansas that developed closed-canopy redcedar forests in the recent past were paired with adjacent grassland sites on similar soil type and topographic position (n = 3 sites/land cover type), and selected soil and plant nitrogen pools and fluxes were measured in replicate plots (n = 6/site) along transects in each forest or grassland site over a 20-mo period. We found few significant differences in median soil inorganic N pools or net N mineralization rates between the forest and grassland sites, though there was a trend for greater concentrations of inorganic N in grassland sites on most sample dates, and cumulative growing season net N mineralization averaged 15% less in forest sites (14.3 kg N-ha-1'yr-1) than in grassland sites (16.9 kg N-ha-'.yr-1). Mean aboveground plant productivity of forest sites (9162 kg ha-1 yr-1) was about 2.5X greater than that of comparable grasslands (similar soils and topographic position), in spite of similar levels of soil N availability. This resulted in an ecosystem-level nitrogen use efficiency (ANPP:litterfall N) in forests that was more than double that of the grasslands they replaced. Additional changes in N cycling associated with redcedar forest development included large accumulations of N in aboveground biomass and transfer to the forest floor via litterfall; redcedar aboveground biomass contained 617 kg N/ ha, forest floor litter N was 253 kg N/ha, and litterfall N flux was 41 kg ha-l'yr-1. These are substantial increases in aboveground biomass N accumulation, surface litter N inputs, and surface litter N accumulation compared to the native grasslands characteristic of this region. These fundamental shifts in ecosystem patterns and processes have the potential to alter regional biogeochemistry and both nitrogen and carbon storage throughout areas of the eastern Central Plains where coverage of redcedars is increasing.
    • An expanded fish-based index of biotic integrity for Great Lakes coastal wetlands

      Cooper, Matthew J.; Lambertu, Gary A.; Moerke, Ashley H.; Ruetz, Carl R.; Wilcox, Douglas A.; The College at Brockport (1/1/2018)
      Biotic indicators are useful for assessing ecosystem health because the structure of resident communities generally reflects abiotic conditions integrated over time. We used fish data collected over 5 years for 470 Great Lakes coastal wetlands to develop multimetric indices of biotic integrity (IBI). Sampling and IBI development were stratified by vegetation type within each wetland to account for differences in physical habitat. Metrics were evaluated against numerous indices of anthropogenic disturbance derived from water quality and surrounding land-cover variables. Separate datasets were used for IBI development and testing. IBIs were composed of 10–11 metrics for each of four vegetation types (bulrush, cattail, water lily, and submersed aquatic vegetation). Scores of all IBIs correlated well with disturbance indices using the development data, and the accuracy of our IBIs was validated using the testing data. Our fish IBIs can be used to prioritize wetland protection and restoration efforts across the Great Lakes basin. The IBIs will also be useful in monitoring programs mandated by the Agreement between Canada and the United States of America on Great Lakes Water Quality, such as for assessing Beneficial Use Impairments (BUIs) in Great Lakes Areas of Concern, and in other ecosystem management programs in Canada and the USA.
    • Application of a Geomorphic and Temporal Perspective to Wetland Management

      Smith, Loren M.; Euliss, Ned H.; Wilcox, Douglas A.; Brinson, Mark M.; East Carolina University; Oklahoma State University - Main Campus; The College at Brockport; U.S. Geological Survey (9/1/2008)
      The failure of managed wetlands to provide a broad suite of ecosystem services (e.g., carbon storage, wildlife habitat, ground-water recharge, storm-water retention) valuable to society is primarily the result of a lack of consideration of ecosystem processes that maintain productive wetland ecosystems or physical and social forces that restrict a manager’s ability to apply actions that allow those processes to occur. Therefore, we outline a course of action that considers restoration of ecosystem processes in those systems where off-site land use or physical alterations restrict local management. Upon considering a wetland system, or examining a particular management regime, there are several factors that will allow successful restoration of wetland services. An initial step is examination of the political/social factors that have structured the current ecological condition and whether those realities can be addressed. Most successful restorations of wetland ecosystem services involve cooperation among multiple agencies, acquisition of funds from non-traditional sources, seeking of scientific advice on ecosystem processes, and cultivation of good working relationships among biologists, managers, and maintenance staff. Beyond that, in on-site wetland situations, management should examine the existing hydrogeomorphic situation and processes (e.g., climatic variation, tides, riverine flood-pulse events) responsible for maintenance of ecosystem services within a given temporal framework appropriate for that wetland’s hydrologic pattern. We discuss these processes for five major wetland types (depressional, lacustrine, estuarine, riverine, and man-made impoundments) and then provide two case histories in which this approach was applied: Seney National Wildlife Refuge with a restored fen system and Bosque del Apache National Wildlife Refuge where riverine processes have been simulated to restore native habitat. With adequate partnerships and administrative and political support, managers faced with degraded and/or disconnected wetland processes will be able to restore ecosystem services for society in our highly altered landscape by considering wetlands in their given hydrogeomorphic setting and temporal stage.
    • Burrowing Saves Lake Erie Clams

      Nichols, S. Jerrine; Wilcox, Douglas A.; The College at Brockport; U.S. Geological Survey (10/1/1997)
      Native clams seem to have been protected from zebra mussel infestation at Metzger Marsh by the interaction between warm temperatures and soft sediments. Warm water encourages burrowing, but soft sediments are required to allow encrusted clams to burrow. In support of this conclusion, we have since found live unionids or fresh shells at three other Lake Erie wetlands.
    • Caddisflies (Insecta: Trichoptera) of Fringing Wetlands of the Laurentian Great Lakes

      Armitage, Brian J.; Hudson, Patrick L.; Wilcox, Douglas A.; Midwest Biodiversity Institute, Inc.; The College at Brockport; U.S. Geological Survey (9/1/2001)
      Fringing wetlands of the Laurentian Great Lakes are subject to natural processes, such as water-level fluctuation and wave-induced erosion, and to human alterations. In order to evaluate the quality of these wetlands over space and time, biological communities are often examined. Ideally, the groups of organisms selected for these evaluations should be resident in the wetlands themselves. Fish are often sampled, but many species are not truly resident, visiting wetlands on an occasional basis to feed or on a seasonal basis to breed. Aquatic vascular plants are perhaps the most common group selected for evaluation. However, in some cases, aquatic plants give a false impression by providing photosynthetic capabilities and structural infrastructure but having greatly diminished herbivore and carnivore communities.
    • Cattail Invasion of Sedge Meadows Following Hydrologic Disturbance in the Cowles Bog Wetland Complex, Indiana Dunes National Lakeshore

      Wilcox, Douglas A.; Apfelbaum, Steven I.; Hiebert, Ronald D.; Applied Ecological Services; The College at Brockport (12/1/1984)
      The vegetation of the 80.7 hectare Cowles Bog Wetland Complex has been altered from its historic mixed sedge-grass domination (Carex stricta, Calamagrostis canadensis) in lower areas and woody growth in slightly elevated areas , as based on archival aerial photographs from 1938-1982 and recent field data. Cattails (Typha spp.) were present in 1938 and made minor gains in cover through 1970. However, the major invasion of cattails appears to be associated with stabilized, increased water levels caused by seepage from diked ponds constructed upgradient from the wetland in the early 1970s. The water level increases are assumed to have been of a magnitude which adversely affected the sedge-grass community but did not preclude cattail growth. The cattail vegetation type increased in cover from 2.0 ha in 1938 to 9.7 ha in 1970 to 37.5 ha in 1982. The sedge-grass vegetation type correspondingly decreased from 56.4 ha to 43.0 ha to 5.7 ha. Cattail invasion appears to have occurred through establishment of disjunct colonies by seed reproduction; followed by vegetative expansion and merging of the colonies.
    • Cattail Invasion of Sedge/Grass Meadows in Lake Ontario: Photointerpretation Analysis of Sixteen Wetlands over Five Decades

      Wilcox, Douglas A.; Kowalski, Kurt P.; Hoare, Holly L.; Carlson, Martha L.; Morgan, Heather N.; The College at Brockport; U.S. Geological Survey; University of Michigan - Ann Arbor (1/1/2008)
      Photointerpretation studies were conducted to evaluate vegetation changes in wetlands of Lake Ontario and the upper St. Lawrence River associated with regulation of water levels since about 1960. The studies used photographs from 16 sites (four each from drowned river mouth, barrier beach, open embayment, and protected embayment wetlands) and spanned a period from the 1950s to 2001 at roughly decadal intervals. Meadow marsh was the most prominent vegetation type in most wetlands in the late 1950s when water levels had declined following high lake levels in the early 1950s. Meadow marsh increased at some sites in the mid-1960s in response to low lake levels and decreased at all sites in the late 1970s following a period of high lake levels. Typha increased at nearly all sites, except waveexposed open embayments, in the 1970s. Meadow marsh continued to decrease and Typha to increase at most sites during sustained higher lake levels through the 1980s, 1990s, and into 2001. Most vegetation changes could be correlated with lake-level changes and with life-history strategies and physiological tolerances to water depth of prominent taxa. Analyses of GIS coverages demonstrated that much of the Typha invasion was landward into meadow marsh, largely by Typha × glauca. Lesser expansion toward open water included both T. × glauca and T. angustifolia. Although many models focus on the seed bank as a key component of vegetative change in wetlands, our results suggest that canopy-dominating, moisture- requiring Typha was able to invade meadow marsh at higher elevations because sustained higher lake levels allowed it to survive and overtake sedges and grasses that can tolerate periods of drier soil conditions.
    • Cattails as far as the eye can see

      Wilcox, Douglas A.; The College at Brockport (5/1/2011)
      This SWS Research Brief summarizes recently publicized information regarding the effects of lake-level regulation on wetlands, and the predictive models for evaluating the potential effects of proposed new regulations plans on wetland plant communities.
    • Changes in Wetland Vegetation in Regulated Lakes in Northern Minnesota, USA Ten Years after a New Regulation Plan Was Implemented

      Meeker, James E.; Wilcox, Douglas A.; Harris, Alan G.; The College at Brockport (1/1/2018)
      Lake-level regulation alters wetland plant communities and their role in providing faunal habitat. Regulation plans have sometimes been changed to restore ecosystem function; however, few studies have shown the effects of such changes. In 2000, a new plan was implemented for regulation of Rainy Lake and Namakan Reservoir in northern Minnesota, USA. We had studied wetland plant communities under the previous 1970 regulation plan in 1987 and used those data to evaluate changes during 2002–2006 and 2010 resampling efforts using the same methods. Ordinations showed that plant communities changed little on Rainy Lake, where regulation changes were minor. However, on Namakan Reservoir, substantial changes had occurred in both vegetation and faunal habitat within two years, as plants favored by dewatering were replaced by submersed aquatic plants favored by year-round flooding under the new 2000 regulation plan. After ten years, Namakan showed greater similarity to unregulated Lac La Croix but still differed overall. Longer-term studies may be needed to determine if the regulation-plan change continues to alter Namakan plant communities. The speed at which changes began suggests that studies on other regulated lakes should begin in the first growing season following implementation of a new regulation plan and should continue periodically for a decade or longer.
    • Changes in zooplankton community, and seston and zooplankton fatty acid profiles at the freshwater/saltwater interface of the Chowan River, North Carolina

      Lichti, Deborah A.; Rinchard, Jacques; Kimmel, David G.; Lichti, Deborah; Rinchard, Jacques; Kimmel, David G.; East Carolina University; The College at Brockport (8/16/2017)
      The variability in zooplankton fatty acid composition may be an indicator of larval fish habitat quality as fatty acids are linked to fish larval growth and survival. We sampled an anadromous fish nursery, the Chowan River, during spring of 2013 in order to determine how the seston fatty acid composition varied in comparison with the zooplankton community composition and fatty acid composition during the period of anadromous larval fish residency. The seston fatty acid profiles showed no distinct pattern in relation to sampling time or location. The mesozooplankton community composition varied spatially and the fatty acid profiles were typical of freshwater species in April. The Chowan River experienced a saltwater intrusion event during May, which resulted in brackish water species dominating the zooplankton community and the fatty acid profile showed an increase in polyunsaturated fatty acids (PUFA), in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The saltwater intrusion event was followed by an influx of freshwater due to high precipitation levels in June. The zooplankton community composition once again became dominated by freshwater species and the fatty acid profiles shifted to reflect this change; however, EPA levels remained high, particularly in the lower river. We found correlations between the seston, microzooplankton and mesozooplankton fatty acid compositions. Salinity was the main factor correlated to the observed pattern in species composition, and fatty acid changes in the mesozooplankton. These data suggest that anadromous fish nursery habitat likely experiences considerable spatial variability in fatty acid profiles of zooplankton prey and that are correlated to seston community composition and hydrodynamic changes. Our results also suggest that sufficient prey density as well as a diverse fatty acid composition is present in the Chowan River to support larval fish production.
    • Changes in zooplankton community, and seston andzooplankton fatty acid profiles at the freshwater/saltwater interface of the Chowan River, North Carolina

      Lichti, Deborah; Rinchard, Jacques; Kimmel, David G.; East Carolina University; NOAA Fisheries, Alaska Fisheries Science Center; The College at Brockport (8/16/2017)
      The variability in zooplankton fatty acid composition may be an indicator of larval fish habitat quality as fatty acids are linked to fish larval growth and survival. We sampled an anadromous fish nursery, the Chowan River, during spring of 2013 in order to determine how the seston fatty acid composition varied in comparison with thezooplanktoncommunitycompositionandfattyacidcompositionduringtheperiod of anadromous larval fish residency. The seston fatty acid profiles showed no distinct pattern in relation to sampling time or location. The mesozooplankton community composition varied spatially and the fatty acid profiles were typical of freshwater species in April. The Chowan River experienced a saltwater intrusion event during May,whichresultedinbrackishwaterspeciesdominatingthezooplanktoncommunity andthefattyacidprofileshowedanincreaseinpolyunsaturatedfattyacids(PUFA),in particulareicosapentaenoicacid(EPA)anddocosahexaenoicacid(DHA).Thesaltwater intrusioneventwasfollowedbyaninfluxoffreshwaterduetohighprecipitationlevels in June. The zooplankton community composition once again became dominated by freshwaterspeciesandthefattyacidprofilesshiftedtoreflectthischange;however,EPA levels remained high, particularly in the lower river. We found correlations between the seston, microzooplankton and mesozooplankton fatty acid compositions. Salinity was the main factor correlated to the observed pattern in species composition, and fatty acid changes in the mesozooplankton. These data suggest that anadromous fish nursery habitat likely experiences considerable spatial variability in fatty acid profiles of zooplankton prey and that are correlated to seston community composition and hydrodynamic changes. Our results also suggest that sufficient prey density as well as a diverse fatty acid composition is present in the Chowan River to support larval fish production.