Lake Mattamuskeet Research Articles

Virtually Engineering Community Engagement: Training for Undergraduate Engineers During the COVID-19 Pandemic

Flood mitigation and adaptation measures, among other tools to improve resiliency, will be necessary to sustain coastal communities in the face of climate change. Key to successful adaptation will be engineering projects, and critical to the success of those projects will be community engagement and support. Despite the recognized importance of community engagement when addressing complex issues like coastal flooding on which engineers work, most undergraduate engineering programs offer little to no training in community engagement. In this paper, we describe our experiences working with undergraduate engineering students to develop community-driven designs to address flooding and water quality issues in the Lake Mattamuskeet watershed in eastern North Carolina. Through an interdisciplinary approach, student teams learned to engage with local stakeholders to better integrate local knowledge and address issues identified by community members in their designs. Because of the COVID-19 pandemic, all community engagement aspects of the project moved to virtual forums, and we discuss the impact this shift had on the engineering designs as well as student learning outcomes and community connections.

Largemouth Bass Hatchery Contributions Quantified via Parentage‐Based Tagging

AbstractLargemouth Bass Micropterus salmoides are the focus of a billion‐dollar (US$1 × 109) recreational fishery in North America and are subject to widespread hatchery supplementation efforts. Parentage‐based tagging (PBT) uses genetic samples taken from hatchery broodstock to genetically “tag” offspring and represents a valuable approach to inform fisheries management and assess hatchery contributions in the wild. This study used a robust microsatellite panel for PBT with Largemouth Bass that reliably discriminated among individuals and siblings and that had low parentage error rates (i.e., false assignments). Genetic data from three cohorts of hatchery broodstock (184 individuals sampled across 3 years) were used to quantify the impacts of planting 150,346 fingerling Largemouth Bass into Lake Mattamuskeet, North Carolina. Parentage‐based tagging detected low overall levels of hatchery contributions in the wild (4.1%), which varied as a function of collection year (range = 1.5–7.7%). Furthermore, hatchery contributions varied by broodstock cohort, with PBT detections being attributed to broodstock from only two of the three stocking years. The application of PBT for Largemouth Bass represents a cost‐effective and practical approach to tag large numbers of hatchery offspring, monitor supplementation efforts, and evaluate the efficacy of different hatchery practices.

Life Stage, Gender and Movement of Blue Crabs (Callinectis sapidus) in Lake Mattamuskeet and Connecting Canals

In their ranges on east and south coasts of the Americas as well as their established invasions in the Adriatic and Baltic, blue crabs, Callinectis sapidus, inhabit estuaries, sounds and coastal oceans and are commercially and ecologically important. How crabs move in response to physical variables is important to management. We monitored life stages at canal control structures, assessed gender ratios with recreational crabbing, learned from crabbers, and studied movements of tagged crabs in a canal connecting Lake Mattamuskeet to the Pamlico sound. Juveniles enter the lake through two of 4 canals connecting to the sounds. Females migrate out through one canal. The lake standing population is about 70% male. Movements of 240 crabs in August 2012 and 102 crabs in October 2014 were quantified using RFID tags with co-located meteorological and oceanographic devices. Non-spawning females and males are nomadic. Crabs released in the canal move in response to changes in water depth and go with the flow, toward the Pamlico Sound (summer 76% and fall 78%). What crabbers describe as a fall migration appears to be concentration of crabs in warmer deeper canals and then southern movement with flow generated by strong north winds. To be effective, management strategies like migratory corridors require understanding of crab movements.

Where's the Grass? Disappearing Submerged Aquatic Vegetation and Declining Water Quality in Lake Mattamuskeet

Abstract Major threats to aquatic systems such as shallow lakes can include declining water quality, the loss of macrophyte beds, and the occurrence of harmful algal blooms. Often, these changes go unnoticed until a shift from a clear, oligotrophic system dominated by macrophyte beds to a turbid, eutrophic system dominated by phytoplankton and associated harmful algal blooms has occurred. Lake Mattamuskeet, which mostly lies within the boundary of Mattamuskeet National Wildlife Refuge, North Carolina, is a shallow lake that has recently experienced a reduction in water clarity and macrophyte beds, also referred to as submerged aquatic vegetation (SAV), and an increase in nutrients, phytoplankton, harmful algal blooms, and cyanotoxin production. At Lake Mattamuskeet, SAV coverage and water clarity declined between the 1980s and 2015. During the same time, significantly increasing trends in nitrogen, phosphorus, turbidity, suspended sediments, chlorophyll a, and pH occurred. Current water-quality conditions (2012–2015) are not conducive to SAV survival and, in some cases, do not meet North Carolina water-quality standards for the protection of aquatic life. Water clarity declines appear to predate the SAV die-offs on the east side. Moving forward, SAV will serve as a primary indicator for lake health; and lake monitoring, research, and management efforts will focus on the restoration of aquatic grasses and water quality at Lake Mattamuskeet.

Age and growth, reproductive biology, and histology in Atlantic needlefish (Strongylura marina) in a coastal freshwater lake

The Atlantic needlefish (Strongylura marina) is a coastal epipelagic species inhabiting shallow coastal waters along the western Atlantic coast from Maine to Brazil. Little has been published about the species due to lack of commercial or sport value. A population exists in Lake Mattamuskeet, a coastal lake connected to Pamlico Sound (NC, USA) via four man-made canals, and fish access is controlled by water-control structures. Herein we describe the life history and age and growth dynamics of the species in the lake. Based on anecdotal and state reports, we believe this species may exhibit anadromy. Sampling was from March to May 1997 and 1998, and from March to October 2001. We also collected from another coastal watershed to complete the length distribution. Spring adults had a high gonadosomatic index compared with autumn (fall) adults, which had atresia. No eggs or age-0 fish were captured in the lake during summer. The four length cohorts matched growth and back-calculated length at age. Otoliths were linearly related to fish length and were used for ageing and growth calculations. Although we found no direct evidence of spawning, data compilation suggests that Atlantic needlefish could be using this lake for reproduction.

Use of Limited Data to Model Lake Water Clarity from Remote Sensed Data in Lake Mattamuskeet, North Carolina

Use of Limited Data to Model Lake Water Clarity from Remote Sensed Data in Lake Mattamuskeet, North Carolina

Waterfowl Impoundments as Sources of Nitrogen Pollution

Hydrologically controlled moist-soil impoundment wetlands provide critical habitat for high densities of migratory bird populations. Nutrients exported from heavily used impoundments by prescribed seasonal drawdown of surface water may contribute to the eutrophication of aquatic ecosystems. To investigate the relative importance of nutrient export from managed impoundment habitats, we conducted a field study at Mattamuskeet National Wildlife Refuge in North Carolina, USA, which contains 1545 ha of impoundments that drain into hypereutrophic Lake Mattamuskeet. We found that prescribed hydrologic drawdowns of an impoundment exported roughly the same amount of nitrogen (N) as adjacent fertilized agricultural fields on a per-area basis and contributed approximately one fifth of total N load to Lake Mattamuskeet. The prescribed drawdown regime, designed to maximize waterfowl production in impoundments, may be exacerbating the degradation of habitat quality in the downstream lake as an unintended consequence. Few studies of wetland N dynamics have targeted impoundments managed to provide wildlife habitat, but a similar phenomenon may occur in some of the 36,000 ha of similarly managed moist-soil impoundments on National Wildlife Refuges in the southeastern USA, especially those hosting dense concentrations of waterfowl. We suggest an earlier seasonal drawdown could potentially mitigate impoundment N pollution and estimate it could reduce N export from our study impoundment by more than 70 %.

Burning peat and reworking loess contribute to the formation and evolution of a large Carolina-bay basin

Carolina bays are nearly ubiquitous along ~1300km of the North American Atlantic Coastal Plain, but relatively few bays have been examined in detail, making their formation and evolution a topic of controversy. The Lake Mattamuskeet basin, eastern North Carolina, USA, is a conglomeration of multiple Carolina bays that form a >162km2 lake. The eastern shoreline of the lake is made up of a 2.9-km-wide plain of parabolic ridges that recorded rapid shoreface progradation. The lower shoreface deposit contains abundant charcoal beds and laminae dated 6465–6863calyr BP, corresponding with initiation of a lacustrine environment in the eastern part of the lake. A core from the western part of the lake sampled a 1541–1633calyr BP charcoal bed at the base of the lacustrine unit, indicating formation of this part of the basin postdates the eastern basin. Lake Mattamuskeet has no relationship to the Younger Dryas or a linked impact event because rim accretion significantly postdates 12,000calyr BP. The shoreline progradation, and association of charcoal beds with the oldest lake sediment in both main parts of the basin, suggest that fire and subsequent hydrodynamic processes were associated with initial formation of these Carolina bays.

The development and persistence of alternative ecosystem states in a large, shallow lake

Summary1. Palaeolimnological data were used to investigate drivers of the community of primary producers in Lake Mattamuskeet, North Carolina, U.S.A. This is a large, shallow lake with two basins currently dominated by phytoplankton and macrophytes. The two basins were divided in 1940 by the building of a roadway across the lake, which also corresponded with the divergence in their ecosystem state.2. Photosynthetic pigments, organic matter and nutrients (P, N, C, S) were analysed in sediment cores from each basin to reconstruct the primary producer community over the past c. 100 years. We sought to answer two questions. First, what changes to the ecosystem resulting from the building of the roadway caused the development of different primary producer communities in the two basins? Second, why have the alternative ecosystem states persisted despite a variety of human perturbations since 1940?3. K‐means cluster analysis and principal component analysis were applied to identify three sediment types based on photosynthetic pigment data: sediments indicating low productivity (low pigment concentrations), sediments associated with macrophytes (chlorophyll a and b) and with phytoplankton (alloxanthin and aphanizophyll). In addition, other palaeolimnological proxies measured, such as loss on ignition, total phosphorus, total organic carbon/total nitrogen and other nutrients, were different in post‐1940 sediments within the two basins.4. These differences suggest characteristics, such as nutrient cycling, water depth and other physical changes resulting from roadway construction, combined to establish and maintain the differing communities of primary producers in the two basins. Furthermore, Fe/S dynamics and waterfowl herbivory probably contributed to the development of the two ecosystem states.

Shallow lake trophic status linked to late Holocene climate and human impacts

Lake Mattamuskeet, North Carolina, USA is a large (162 km 2 ) and shallow (mean depth = 1m ) coastal lake, which was significantly modified to support agricultural activities following European settlement in 1850. Paleolimnological proxies mea- sured on a 400-cm sediment core collected from Lake Mattamuskeet reveal shifts in organic matter input and primary producer community structure in response to climatic and human impacts on the lake during the late Holocene. Stratigraphic changes in organic matter content, nutrients, metals, lignin phe- nols and photosynthetic pigments were used to divide the sediment core into three intervals. Interval I includes sediment deposited between A.D. 360-1584 and indicates a clear-water, sand-bottom state with low algal abundance. In addition, the lake catchment area experienced two significant fires during this interval that were recorded as charcoal layers in the core around A.D. 360 and A.D. 1435 (calibrated 14 C AMS dates). Trophic structure changed with the onset of Interval II (A.D. 1584-1860) when total algal abundance increased, and the primary producer com- munity was comprised primarily of diatoms, chrysophytes, cryptophytes and cyanobacteria. Dur- ing this interval there was also an increase in terrestrial organic material input into the lake as well as a shift in plant type from woody gymnosperms to non-woody angiosperms as determined from lignin data. Sediment deposited in Lake Mattamuskeet following European settlement (Interval III, A.D. 1860-present) suggests a dramatic increase in organic- matter deposition, metals, primary-producer abun- dance and the onset of cyanobacterial dominance. Sedimentary evidence indicates that shallow-water primary producers can respond rapidly to climate change and human development.

Fish and Blue Crab Passage through Water Control Structures of a Coastal Bay Lake

AbstractCoastal bay lakes in the southeastern United States may be connected to coastal waters by natural openings or artificial channels, but often access to them by aquatic organisms is restricted by water control structures (WCSs) designed to minimize saltwater intrusion into freshwater habitats. Our study examined movements of alewife Alosa pseudoharengus, white perch Morone americana, American eel Anguilla rostrata, and blue crab Callinectes sapidus through two WCSs separating Lake Mattamuskeet, North Carolina, and canals leading to Pamlico Sound. All WCSs were located on Mattamuskeet National Wildlife Refuge property. Three WCS designs were tested for fish passage efficiency. The original wooden flapgate configuration was hinged at the top, which opened the full width of the embayment and was pressure activated from lake levels. A replacement design, installed in each WCS embayment in 1987, was a wooden stopblock containing a small, hinged stainless steel flapgate mounted near the bottom. This design minimized saltwater intrusion but required a considerable lakeside head to open. High water velocities produced conditions unfavorable for alewife and blue crab passage, but some species, especially white perch, were capable of moving through the restrictive opening. Small, experimental slotted weirs installed in the stopblocks near the surface passed organisms more effectively than the stainless steel flapgates. After 10 years of steel flapgate operation, the alewife spawning run into Lake Mattamuskeet decreased from an estimated high of 199,600 fish in 1970 to only 178 fish in 1997 and 454 fish in 1998. In 1999, wooden flapgates of the original design were installed experimentally, which resulted in favorable conditions (wider aperture and reduced velocities) for fish and blue crab passage. Reverting to the original flapgate design should maintain the mixed community of freshwater and marine–estuarine species in the lake.

SEASONAL BELOWGROUND HERBIVORY AND A DENSITY REFUGE FROM WATERFOWL HERBIVORY FOR VALLISNERIA AMERICANA

Studies of aquatic food webs rarely address the role of migratory waterfowl, even though they are ubiquitous and many are omnivorous. Several species of waterfowl consume belowground plant tubers during winter, yet the impact of such herbivory on future plant abundance is mostly unknown. To test the impact of wintering waterfowl on submerged vegetation, we installed waterfowl exclosures (N = 5) and reference plots (N = 5) open to grazing in Lake Mattamuskeet, North Carolina, USA, where Vallisneria americana (water celery, or tapegrass) dominated the plant community. Over the three-year study period, we sampled above- and belowground plant standing stock every 2–3 mo. Reference plots had a lower density (number per square meter) of Vallisneria tubers than ungrazed exclosures (repeated-measures ANOVA treatment P = 0.038, time × treatment P = 0.025). Percentage loss of tubers in reference plots was positively related to the density of tubers at the onset of winter (R2 = 0.294, P = 0.026). Despite significant reduction of tubers during winter, no detectable carryover effects of waterfowl exclosure on Vallisneria aboveground biomass occurred in subsequent growing seasons (rmANOVA treatment P = 0.342, time × treatment P = 0.539). Our study detected a threshold tuber density below which waterfowl herbivory on Vallisneria did not occur. Therefore, our results suggest that limits on waterfowl foraging efficiency provide a refuge for aquatic plants subject to intense, seasonal predation.

Food Dispersion and Foraging Energetics: A Mechanistic Synthesis for Field Studies of Avian Benthivores

Much effort has focused on modeling and measuring the energy costs of free existence and the foraging strategies of animals. However, few studies have quantitatively linked these approaches to the patch structure of foods in the field. We developed an individual—based model that relates field measurements of the dispersion of benthic foods to search costs and foraging profitability of diving ducks. On Lake Mattamuskeet, North Carolina, Canvasback ducks (Aythya valisineria) eat only the belowground winter buds of the submerged plant Vallisneria americana. We measured and modeled the patch structure of winter buds at the level of potential foraging "loci," defined as contiguous circles 1 m in diameter. In the field and in the model, Canvasbacks make repeated vertical dives in such loci, foraging in the sediments by touch, before surface—swimming to another locus. We quantified first—order patchiness by fitting a negative binomial distribution to core samples taken at 50—m intervals along transects, to yield the frequencies of loci with different bud densities. Second—order patchiness was measured by taking cores at 1—m increments radiating from each sampling point, and regressing bud density at each sampling point on densities at these increments. No significant correlations were found, indicating that Canvasbacks could not predict food densities based on densities in nearby foraging loci. For the model, we generated food grids from the negative binomial distributions of core samples. Energy costs of diving were calculated by applying aerobic efficiencies (mechanical power output $\div$ aerobic power input) to biomechanical models. Unlike respirometry alone, this method accounts for effects on dive costs of varying water depth and dive duration. We used measurements of Canvasback intake rates at different bud densities to calculate profitability (energy intake minus expenditure) for each dive. Multivariate uncertainty analyses (Latin hypercube) indicated that profitability for Canvasbacks foraging on Vallisneria buds is determined mainly by food—item size and locomotor costs of descent. Bud metabolizable energy, water temperature, bud dispersion, and search and handling time coefficients of the functional response for intake rate have relatively minor influence. Individual—parameter perturbations indicated that to maintain the same foraging benefits, the total area of Vallisneria habitat would have to increase by 1.4—fold if dry mass per bud decreased from 0.10 to 0.03 g, and by 2.1—fold if water depth increased from 0.5 to 2 m. Our method allows study of interactions between patch structure and foraging energetics without detailed spatial mapping of foods, which is not feasible at appropriate scales for highly mobile benthivores. The model yields estimates of energy balance, contaminant intake, and amount and quality of foraging habitat required to sustain diving duck populations under varying environmental conditions. More accurate prediction of giving—up times and giving—up food densities will require better understanding of the time scale over which ducks balance their energy budgets.

Movements and Spawning of Anadromous Alewives, Alosa pseudoharengus (Wilson) at Lake Mattamuskeet, North Carolina

Abstract Adult anadromous alewives were captured during spring spawning runs into Lake Mattamuskeet, North Carolina in 1969, 1970 and 1971. The peak of the spawning runs occurred on 5 and 6 April 1970, and 2 and 3 April 1971. Average water temperatures on these dates were 12.9 C and 13.1 C, respectively. Seasonal movements of alewives displayed a unimodal peak. Daily activity was greatest between dawn and noon and between dusk and midnight. One of four canals connecting the spawning grounds in the lake with Pamlico Sound carried an average of 97.5% of the alewives into the lake during 1970 and 1971.

Commercial Carp Removal at Lake Mattamuskeet, North Carolina

Commercial Carp Removal at Lake Mattamuskeet, North Carolina