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Permanent URI for this collectionhttps://hdl.handle.net/1969.6/89085

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Crassostrea virginica dredge efficiency in Texas estuaries
(Cambridge University Press, 2019-11-22) Pollack, Jennifer Beseres; Palmer, Terence A.
Quantifying and comparing stocks of oysters (Crassostrea virginica) within and among estuaries across the Gulf of Mexico is difficult because the sampling equipment used is either inconsistent among studies, or inefficient. In Texas, USA, stock assessments of oyster populations are made using an oyster dredge, which is an inefficient sampling tool. We compared sampling densities estimated by oyster dredges with more accurate estimates taken by diver-quadrat samples to determine a dredge efficiency rate. Our calculated efficiency rate (0.125) was negatively affected by the number of dead oysters, and the number and volume of total oysters in an area, but not affected by sediment grain size, water quality, and other oyster metrics. The dredge efficiency rate calculated in this study can be applied to past and future dredge-collected oyster quantity data to provide more realistic estimates of oyster densities and allow more accurate stock assessments and comparisons among studies and regions.
Developing a bioassessment framework to inform tidal stream management along a hydrologically variable coast
(Ecological Indicators, 2024-03-02) Alexis J. Neffinger; Natasha J. Breaux; Abraham D. Margo; Terence A. Palmer; Stacy N. Trackenberg; Jennifer Beseres Pollack
Tidal streams are spatiotemporally varying areas that encompass tidally influenced limnetic and oligohaline zones within estuaries. These areas are important for many biogeochemical processes and for the life cycles of many fishery species. However, tidal streams are also susceptible to impairment from coastal development and watershed-derived runoff, which potentially affects faunal assemblages within the ecosystem. This study developed indices of biotic integrity (IBIs) for nekton and benthic macroinfauna in tidal streams along the southern Texas coast. Fifteen tidal stream sites with mean salinities ranging from 0.4 to 11.9 were classified as degraded if their surrounding land use was > 20 % urban or agricultural, watershed population density was > 50 km−2, and nutrient and chlorophyll concentrations exceeded specific screening limits. Otherwise, sites were classified as reference. Nekton and benthic macroinfauna communities were then sampled at these fifteen stream sites in 2020 and 2021. Historical metrics and metrics derived from multivariate analyses were considered for inclusion in the IBIs, and were assessed for collinearity, redundancy, suitability for score assignment, and agreement with historical literature. Nine univariate nektonic metrics (including total abundance, number of invertebrate taxa, and the percent abundance of five species, one family, and one functional group) and six benthic macroinfauna metrics (including Shannon’s diversity, total abundance and biomass, and the percent abundance of two taxa and one functional group) were incorporated into separate nektonic and benthic IBIs. Mean IBI scores of reference sites were greater than degraded sites by 42 % for nekton and 30 % for benthic macroinfauna. Seven out of eight reference sites had greater mean nekton IBI scores than the mean scores of all seven degraded sites, while four of eight reference sites had greater benthic IBI scores than all degraded sites. However, overlap in the ranges of scores calculated for degraded and reference sites occurred, which is likely caused by spatiotemporal variability, including stream size variation and the changing climatic and biogeographical gradient along the southern Texas coast. The IBIs developed in this study represent an important preliminary step in bioassessment development for Texas tidal streams, and will help to provide a useful tool for coastal environmental management.
Divergence in salinity tolerance of northern Gulf of Mexico eastern oysters under field and laboratory exposure
(Conservation Physiology, 2021-08-23) Marshall, Danielle A.; Casas, Sandra M.; Walton, William C.; Rikard, F. Scott; Palmer, Terence A.; Breaux, Natasha J.; La Peyre, Megan K.; Pollack, Jennifer Beseres; Kelly, Morgan; La Peyre, Jerome F.
The eastern oyster, Crassostrea virginica, is a foundation species within US Gulf of Mexico (GoM) estuaries that has experienced substantial population declines. As changes from management and climate are expected to continue to impact estuarine salinity, understanding how local oyster populations might respond and identifying populations with adaptations to more extreme changes in salinity could inform resource management, including restoration and aquaculture programs. Wild oysters were collected from four estuarine sites from Texas [Packery Channel (PC): 35.5, annual mean salinity, Aransas Bay (AB): 23.0] and Louisiana [Calcasieu Lake (CL): 16.2, Vermilion Bay (VB): 7.4] and spawned. The progeny were compared in field and laboratory studies under different salinity regimes. For the field study, F1 oysters were deployed at low (6.4) and intermediate (16.5) salinity sites in Alabama. Growth and mortality were measured monthly. Condition index and Perkinsus marinus infection intensity were measured quarterly. For the laboratory studies, mortality was recorded in F1 oysters that were exposed to salinities of 2.0, 4.0, 20.0/22.0, 38.0 and 44.0 with and without acclimation. The results of the field study and laboratory study with acclimation indicated that PC oysters are adapted to high-salinity conditions and do not tolerate very low salinities. The AB stock had the highest plasticity as it performed as well as the PC stock at high salinities and as well as Louisiana stocks at the lowest salinity. Louisiana stocks did not perform as well as the Texas stocks at high salinities. Results from the laboratory studies without salinity acclimation showed that all F1 stocks experiencing rapid mortality at low salinities when 3-month oysters collected at a salinity of 24 were used and at both low and high salinities when 7-month oysters collected at a salinity of 14.5 were used.
Dynamics of Restored and Natural Oyster Reefs After a Hurricane
(Frontiers in Ecology and Evolution, 2022-01-26) Martinez, Meghan J.; Palmer, Terence A.; Breaux, Natasha J.; Pollack, Jennifer Beseres
Restoration of shellfish reefs has increased exponentially over the past two decades, due in part to increased awareness of widespread oyster habitat loss. Large-scale, acute disturbances such as hurricanes have the potential to influence restoration outcomes, but because storm occurrence is unpredictable with respect to restoration timelines, the responses of restored habitats are not well understood. We quantified the ecological dynamics of a newly constructed Crassostrea virginica oyster reef and nearby reference reef in a Texas estuary immediately after Hurricane Harvey, a major category 4 storm. Biophysical structure (e.g., oyster density, shell height, sediment grain size), and community composition (abundance of reef-associated epifauna, and nearby infauna) were measured for 18 months. A sharp decrease in salinity and temporary deposition of fine sediments within the first 3 months corresponded with increases in oyster and epifaunal recruitment on the restored reef, although densities were generally below those measured on restored reefs without hurricanes. Criteria for oyster reef restoration success were met within 12–18 months post-storm. Infaunal densities decreased but returned to pre-storm densities within 2 months, but bivalves were delayed, returning to pre-storm levels after 9 months. A lack of historical baseline data on the newly restored reef limited our ability to assess the magnitude of reef recovery to pre-disturbance levels or separate the direct effects of the hurricane from the dynamics of early recruitment and growth. Results provide important information about restored and natural oyster reef dynamics after large-scale disturbance and can help inform effective management and conservation measures.
Ecological structure and function in a restored versus natural salt marsh
(PLoS ONE, 2017-12-19) Rezek, Ryan J.; Lebreton, Benoit; Sterba-Boatwright, Blair; Pollack, Jennifer Beseres
Habitat reconstruction is commonly employed to restore degraded estuarine habitats and lost ecological functions. In this study, we use a combination of stable isotope analyses and macrofauna community analysis to compare the ecological structure and function between a recently constructed Spartina alterniflora salt marsh and a natural reference habitat over a 2-year period. The restored marsh was successful in providing habitat for economically and ecologically important macrofauna taxa; supporting similar or greater density, biomass, and species richness to the natural reference during all but one sampling period. Stable isotope analyses revealed that communities from the natural and the restored marshes relied on a similar diversity of food resources and that decapods had similar trophic levels. However, some generalist consumers (Palaemonetes spp. and Penaeus aztecus) were more 13C-enriched in the natural marsh, indicating a greater use of macrophyte derived organic matter relative to restored marsh counterparts. This difference was attributed to the higher quantities of macrophyte detritus and organic carbon in natural marsh sediments. Reduced marsh flooding frequency was associated with a reduction in macrofaunal biomass and decapod trophic levels. The restored marsh edge occurred at lower elevations than natural marsh edge, apparently due to reduced fetch and wind-wave exposure provided by the protective berm structures. The lower elevation of the restored marsh edge mitigated negative impacts in sampling periods with low tidal elevations that affected the natural marsh. The results of this study highlight the importance of considering sediment characteristics and elevation in salt marsh constructions.
Effect of Temporarily Opening and Closing the Marine Connection of a River Estuary
(Estuaries and Coasts, 2022-12-06) Montagna, Paul; Palmer, Terence; Pollack, Jennifer Beseres
The lower Rio Grande is a river-dominated estuary that serves as the border between Texas, USA, and Tamaulipas, Mexico. River estuaries encompass the section of the river influenced by tidal exchange with the Gulf of Mexico, but the connection with the Rio Grande is intermittent and can be temporarily open or closed. During the 4.8-year study period, the river mouth was closed 30% of the time, mostly during average or dry climatic conditions, with the temporary closing of the river mouth being linked to hydrology. When the Rio Grande estuary is closed, salinity is low (1.5 psu compared to 4.8 psu when open), nitrate plus nitrite are low (4.4 μM compared to 31.5 μM when open), and ammonium is high (9.6 μM compared to 4.3 μM when open), but chlorophyll is similar (20 μg/L compared to 21 μg/L when open). Benthic macrofaunal abundance and biomass are higher when the river mouth is closed: 16,700 individuals m−2 and 3.3 g m−2 compared to 8800 individuals m−2 and 2.4 g m−2 when the Rio Grande river mouth is open. Benthic macrofaunal community structure is divided into two groups: chironomid larvae and Oligochaeta dominated when the river mouth was closed, whereas polychaetes Mediomastus ambiseta and Streblospio benedicti dominated when the river mouth was open. The implications of these results for managing freshwater flows are that the open and closed conditions each have a characteristic benthic macrofaunal community that is strongly influenced by system hydrology.
Evaluating Biodegradable Alternatives to Plastic Mesh for Small-scale Oyster Reef Restoration
(Restoration Ecology, 2022-07-07) Comba, Devin; Palmer, Terence A.; Breaux, Natasha J.; Pollack, Jennifer Beseres
Polyethylene plastic mesh is commonly used for containing oyster shells in small-scale oyster reef restoration, but environmental and public health concerns have prompted investigations of biodegradable alternatives. Shallow (<0.5 m) and deep (approximately 1 m) oyster reefs (approximately 6 m2) were constructed in the Mission-Aransas Estuary, Texas, U.S.A., in March 2020 using recycled oyster shells placed into four different replicated mesh bag types: polyethylene (plastic) and three biodegradable alternatives (cellulose, cotton, and jute). Biodegradable alternatives (cellulose, cotton, and jute) all completely degraded within 2 months of deployment, leaving piles of loose shell, while polyethylene bags remained intact. Despite rapid degradation, the biodegradable/loose shell successfully recruited and developed larger oysters (mean of 46 mm) than on the polyethylene-bagged shell (mean of 40 mm) after 7 months, although at less than half the density. Associated motile fauna density in the bagged shell was 2.4 times higher than in the loose shell after 7 months at both the deep and shallow locations. Faunal community composition and diversity varied more with reef depth than by bag type. The total cost of using polyethylene bags was lower than for biodegradable alternatives (22–45% the cost of cellulose, 35–72% the cost of jute, 49–99% the cost of cotton). However, because our estimate of the environmental cost of polyethylene plastic mesh only included impacts on marine natural capital, the true cost is likely much higher. Despite higher costs, biodegradable alternatives can still be successful for use in small-scale oyster restoration events without introducing plastics into the marine environment.
Influence of an industrial discharge on long-term dynamics of abiotic and biotic resources in Lavaca Bay, Texas, USA
(Environmental Monitoring and Assessment, 2022-10-27) Harris, Elizabeth; Montagna, Paul; Douglas, Audrey; Vitale, Lisa; Buzan, David
The current study seeks to identify possible anthropogenic and/or natural environmental stressors that may account for the long-term decline of ecosystem health in Lavaca Bay, Texas, USA. The Formosa Plastics Corporation instituted monitoring of an industrial discharge into the bay with 16 fixed point stations and quarterly sampling from 1993 to 2020. Comprehensive measurements included organic and inorganic solutes in surface water, porewater and sediment, sediment content, plankton, nekton, and infaunal benthos. All parameter trends changed over time due to climate, freshwater inflow events, and/or seasonal changes. Biological community structure and sediment changed with distance from the discharge site. Dominance characterized community structure because three to four taxa comprised > 70% of individuals for nekton (trawl and gill net), phytoplankton, zooplankton, and ichthyoplankton samples. Sediment became sandier over time (48 to 75%) and away from the discharge. Surface water and porewater at reference (R) stations and stations near the discharge site had similar hydrographical and biological trends over time, indicating no long-term impact due to the discharge. However, 99.9% of 424,671 measurements of organic contaminants were non-detectable because the methods were insensitive to ambient concentrations. Thus, it is still not known if contaminants play a role in the long-term decline of ecosystem health in Lavaca Bay. Furthermore, only four R stations were sampled and were all 3810 m from the discharge site, so it is possible that trends in R stations do not represent the natural background. Future studies should include more R stations and lower detection limits for contaminants.
Long-term changes in contamination and macrobenthic communities adjacent to McMurdo Station, Antarctica
(Science of the Total Environment, 2020-10-08) Palmer, Terence A.; Klein, Andrew G.; Sweet, Stephen T.; Montagna, Paul A.; Hyde, Larry J.; Sericano, Jose; Wade, Terry L.; Kennicutt II, Mahlon C.; Pollack, Jennifer Beseres
Improved waste management at McMurdo Station, Antarctica beginning in the 1980s has been followed by decreases in polycyclic aromatic hydrocarbon (PAH) and metal contamination in the adjacent marine sediments. However, determining the effect of the decreased contamination on marine ecological indicators (macrobenthic fauna) is confounded by concurrent changes in climate cycles and other physical forces. Between 2000 and 2013, there was a decrease in concentrations of some contaminants including mercury, copper, organochlorines, and PAHs in marine sediments adjacent to McMurdo Station. PAH concentrations in Winter Quarters Bay decreased an order of magnitude from 2000/2003 to 2012/2013 and were within an order of magnitude of reference area concentrations by 2013. Macrobenthic communities did not indicate any sign of recovery and have not become more similar to reference communities over this same period of time. Temporal changes in macrobenthic community composition during the study period had higher correlations with climatic and sea ice dynamics than with changes in contaminant concentrations. The Interdecadal Pacific Oscillation climatic index had the highest correlation with macrobenthic community composition. The Antarctic Oscillation climatic index, maximum ice extent and other natural environmental factors also appear to influence macrobenthic community composition. Despite large improvements in environmental management at McMurdo Station, continuing environmental vigilance is necessary before any noticeable improvement in ecological systems is likely to occur. The effects of climate must be considered when determining temporal changes in anthropogenic effects in Antarctica. Maintaining long-term monitoring of both contaminants and ecological indicators is important for determining the localized and global influences of humans on Antarctica, which will have implications for the whole planet.
Long-term trends in the response of benthic macrofauna to climate variability in the Lavaca-Colorado Estuary, Texas
(Inter-Research, 2011-08-31) Pollack, Jennifer Beseres; Palmer, Terence A.; Montagna, Paul A.
Long-term trends in the response of benthic macrofauna to hydrological conditions were examined in the Lavaca-Colorado Estuary, Texas. Four stations representing a range of salinities in the Lavaca-Colorado Estuary were sampled quarterly for benthic macrofauna and hydrography from April 1988 to October 2008. The relationship between climate variability and local salinity patterns and benthic populations was investigated using the Oceanic Niño Index (ONI), North Atlantic Oscillation (NAO), and North Pacific Index (NPI). Mean salinity declined during the 20 yr study period. Observed changes in salinity were related to river discharge and the ONI because there were more El Niño events in the first half of the study period relative to the second half. Benthic macrofaunal abundance was significantly correlated with salinity, the ONI and the NAO, indicating that global climate variability and the resulting effects on local salinity patterns are important factors shaping benthic macrofaunal communities. There was no significant linear trend in temperature over time, and negative correlations between individual taxa and temperature were likely due to seasonality. While drivers other than physical hydrological factors can obviously affect benthic macrofaunal communities, strong connections between global climate signals, precipitation, and local salinity patterns provided the most plausible mechanistic connection between climatic variability and benthic macrofaunal response in the estuary. An increasingly unstable climate may lead to potentially strong effects in estuarine ecosystems because stability is known to affect diversity and productivity. The vulnerability of estuarine ecosystems to the effects of climate variability will be exacerbated as human population growth and water resource development continues to increase the demand for and stress on coastal and marine resources.
Medium-term monitoring reveals effects of El Niño Southern Oscillation climate variability on local salinity and faunal dynamics on a restored oyster reef
(PLoS ONE, 2021-08-16) Pollack, Jennifer Beseres; Palmer, Terence A.; Williams, Abby E.
Human activities and regional-scale climate variability drive changes in the ecology of coastal and marine ecosystems. Ecological restoration has emerged as a best-management practice to combat habitat degradation and restore lost ecological functions. However, relatively short project monitoring timeframes have limited our understanding of the effects of interannual climate cycles on water quality and restoration dynamics. We collected measurements on a 23-ha oyster reef constructed in the Gulf of Mexico to determine the relationship between El Niño Southern Oscillation (ENSO)-driven climate variability and local salinity patterns, and to evaluate the effects of this climate variability and salinity on oyster population dynamics and faunal community composition over a medium-term (five-year) timeframe. The role of ENSO-driven climate variability on local salinity patterns (primarily from changes in precipitation and evaporation) and faunal dynamics was investigated using the Oceanic Niño Index (ONI). Salinity was negatively correlated with ONI with an approximately 4-month lag. Higher ONI values (El Niño periods) were followed by reductions in salinity, increases in oyster recruitment and density, and reductions in resident motile fauna density and species richness. Lower ONI values (La Niña periods) had higher and less variable salinities, and higher areal coverage of restoration substrates by large oysters. ENSO-driven salinity reductions in the second year after reef construction coincided with a shift in resident motile faunal community composition that was maintained despite a second strong salinity reduction in year 5. Our results indicate that it is important to expand the typical monitoring timeframes to at least five years so that resource managers and restoration practitioners can better understand how both short-term environmental variability and longer-term climate cycles can affect the outcomes of restoration actions.
Morphological Assessment of the Eastern Oyster Crassostrea virginica throughout the Gulf of Mexico
(Wiley Periodicals LLC, 2021-07-03) Hajovsky, Polly; Pollack, Jennifer Beseres; Anderson, Joel
The eastern oyster Crassostrea virginica is a commercially and ecologically important organism found throughout the western North Atlantic and Gulf of Mexico. Morphological differences in shell shape of eastern oysters are known to arise from environmental, genetic, and husbandry-related factors. Here, live eastern oysters were collected from 17 sites along the U.S. Gulf of Mexico coast from Texas to Florida to examine morphological differences among geographic samples. Six morphological metrics were recorded for each individual, and four different composite ratios commonly used to describe oyster shape (fan, cup, volume ratio, and weight ratio) were calculated. Principal component analysis was used to demonstrate geographic differences in ordinated shape ratios, correlating roughly with eastern (Florida), northern (Alabama, Louisiana, north Texas), and western (south Texas) samples. In Texas, differences in shape were correlated with previously described genetic population boundaries, indicating that populations north versus south of Aransas Bay had different overall shell shapes. On a broader scale, shell shape variation correlated roughly with previously described genetic population boundaries throughout the Gulf of Mexico as well as tide depth (intertidal versus subtidal reefs). Among the various factors that might act as drivers of shell shape, individual variation is important, but population structure and tide height are also significant predictor variables of shape in this species.
Oyster growth across a salinity gradient in a shallow, subtropical Gulf of Mexico estuary
(Cambridge University Press, 2021-02-04) Lebreton, Benoit; Pollack, Jennifer Beseres; Blomberg, Brittany; Palmer, Terence A.; Montagna, Paul A.
An increase in oyster aquaculture as a sustainable method of shellfish production is one response to overharvest and degradation of natural oyster reefs over the past century. Successful aquaculture production requires determining the environmental conditions optimal for oyster growth. In this study, the salinity, temperature, chlorophyll a concentration and the growth of Crassostrea virginica were monitored at four locations within the Mission-Aransas Estuary, Texas (USA), a shallow subtropical estuary influenced by relatively low freshwater inflow. Mean growth of the oyster shell (0.205 mm d–1 and 0.203 g d–1) and soft tissues (3.447 mg d–1) was highest when salinity was low (mean = 15.5) and chlorophyll a concentration was high (8.4 μg l–1). Oyster growth also varied temporally with periods of spawning. In low-inflow estuaries such as the Mission-Aransas Estuary, oyster farms should be sited close to river mouths so that oysters can benefit from freshwater inflows and lower salinities.
Recruitment Dynamics of Serpulid Worms in Baffin Bay, Texas: Implications for Habitat Restoration in a Hypersaline Estuary
(Estuaries and Coasts, 2023-07-19) Natasha Breaux; Auria Avalos; Jennifer Gilmore; Jennifer Beseres Pollack; Jennifer Gilmore
Low inflows cause predominantly hypersaline conditions in Baffin Bay, TX (USA), which are inhospitable for oysters, the dominant reef-builder in other northern Gulf of Mexico estuaries. Instead, extensive biogenic reefs contain dense aggregations of the ubiquitous tube-building serpulid worm, Hydroides dianthus. The distribution and size of these reefs have declined over the last several decades. Although serpulid reef habitats have increased in conservation importance, there is a need for ecological knowledge to inform resource management and habitat restoration planning. This study examined spatial and temporal recruitment patterns of serpulid worms and other encrusting species over an 18-month-long period, using recruitment tiles, and live serpulid reef as a reference. Recruitment of H. dianthus occurs year-round; however, the greatest recruitment occurs between September and December. No consistent differences in serpulid recruitment were detected among locations within Baffin Bay, which could be because salinity and temperature were similar among locations, and/or because sampling replication was low. H. dianthus cover was greater on the lower surface of horizontally oriented recruitment tiles (28% cover), whereas Amphibalanus eburneus (barnacle) cover dominated the upper surface of tiles (34% cover). Furthermore, there is no evidence that predation by megafauna (> 1 cm) is hindering serpulid recruitment. There is sufficient larval supply of H. dianthus to suggest that the restoration of serpulid reefs can be successful by providing additional substrate with appropriate microhabitat complexity. Study findings can be used to support planning and successful implementation of serpulid reef restoration.
Recruitment Dynamics of Serpulid Worms in Baffin Bay, Texas: Implications for Habitat Restoration in a Hypersaline Estuary
(Estuaries and Coasts, 2023-06-24) Breaux, Natasha; Avalos, Auria; Palmer, Terence; Pollack, Jennifer
Low inflows cause predominantly hypersaline conditions in Baffin Bay, TX (USA), which are inhospitable for oysters, the dominant reef-builder in other northern Gulf of Mexico estuaries. Instead, extensive biogenic reefs contain dense aggregations of the ubiquitous tube-building serpulid worm, Hydroides dianthus. The distribution and size of these reefs have declined over the last several decades. Although serpulid reef habitats have increased in conservation importance, there is a need for ecological knowledge to inform resource management and habitat restoration planning. This study examined spatial and temporal recruitment patterns of serpulid worms and other encrusting species over an 18-month-long period, using recruitment tiles, and live serpulid reef as a reference. Recruitment of H. dianthus occurs year-round; however, the greatest recruitment occurs between September and December. No consistent differences in serpulid recruitment were detected among locations within Baffin Bay, which could be because salinity and temperature were similar among locations, and/or because sampling replication was low. H. dianthus cover was greater on the lower surface of horizontally oriented recruitment tiles (28% cover), whereas Amphibalanus eburneus (barnacle) cover dominated the upper surface of tiles (34% cover). Furthermore, there is no evidence that predation by megafauna (>1 cm) is hindering serpulid recruitment. There is sufficient larval supply of H. dianthus to suggest that the restoration of serpulid reefs can be successful by providing additional substrate with appropriate microhabitat complexity. Study findings can be used to support planning and successful implementation of serpulid reef restoration.
Response of macrobenthic communities to changes in water quality in a subtropical, microtidal estuary (Oso Bay, Texas)
(Cambridge University Press, 2020-09-18) de Santiago, Kevin; Palmer, Terence A.; Wetz, Michael S.; Pollack, Jennifer Beseres
The influence of nutrient loading and other anthropogenic stressors is thought to be greater in low inflow, microtidal estuaries, where there is limited water exchange. This 11-month study compared spatial changes in macrofaunal communities adjacent to regions that varied in land cover in Oso Bay, Texas, an estuarine secondary bay with inflow dominated by hypersaline discharge, in addition to discharge from multiple municipal wastewater treatment plants. Macrofauna communities changed in composition with distance away from a wastewater treatment plant in Oso Bay, with the western region of the bay containing different communities than the head and the inlet of the bay. Ostracods were numerically dominant close to the wastewater discharge point. Macrobenthic community composition is most highly correlated with silicate concentrations in the water column. Silicate is negatively correlated with salinity and dissolved oxygen, and positively correlated with nutrients within the bay. Results are relevant for environmental management purposes by demonstrating that point-source discharges can still have ecological effects in hydrologically altered estuaries.
A Restoration Suitability Index Model for the Eastern Oyster (Crassostrea virginica) in the Mission-Aransas Estuary, TX, USA
(PLoS ONE, 2012-07-11) Pollack, Jennifer Beseres; Cleveland, Andrew; Palmer, Terence A.; Reisinger, Anthony S.; Montagna, Paul A.
Oyster reefs are one of the most threatened marine habitats on earth, with habitat loss resulting from water quality degradation, coastal development, destructive fishing practices, overfishing, and storm impacts. For successful and sustainable oyster reef restoration efforts, it is necessary to choose sites that support long-term growth and survival of oysters. Selection of suitable sites is critically important as it can greatly influence mortality factors and may largely determine the ultimate success of the restoration project. The application of Geographic Information Systems (GIS) provides an effective methodology for identifying suitable sites for oyster reef restoration and removes much of the uncertainty involved in the sometimes trial and error selection process. This approach also provides an objective and quantitative tool for planning future oyster reef restoration efforts. The aim of this study was to develop a restoration suitability index model and reef quality index model to characterize locations based on their potential for successful reef restoration within the Mission-Aransas Estuary, Texas, USA. The restoration suitability index model focuses on salinity, temperature, turbidity, dissolved oxygen, and depth, while the reef quality index model focuses on abundance of live oysters, dead shell, and spat. Size-specific Perkinsus marinus infection levels were mapped to illustrate general disease trends. This application was effective in identifying suitable sites for oyster reef restoration, is flexible in its use, and provides a mechanism for considering alternative approaches. The end product is a practical decision-support tool that can be used by coastal resource managers to improve oyster restoration efforts. As oyster reef restoration activities continue at small and large-scales, site selection criteria are critical for assisting stakeholders and managers and for maximizing long-term sustainability of oyster resources.
Role and Value of Nitrogen Regulation Provided by Oysters (Crassostrea virginica) in the Mission-Aransas Estuary, Texas, USA
(PLoS ONE, 2013-06-06) Pollack, Jennifer Beseres; Yoskowitz, David; Kim, Hae-Cheol; Montagna, Paul A.
Suspension-feeding activities of oysters impart a potentially significant benefit to estuarine ecosystems via reduction of water column nutrients, plankton and seston biomass, and primary productivity which can have a significant impact on human well-being. This study considered nitrogen regulation by eastern oysters Crassostrea virginica in the Mission-Aransas Estuary, Texas, USA, as a function of denitrification, burial, and physical transport from the system via harvest. Oyster reefs were estimated to remove 502.5 kg N km−2 through denitrification of biodeposits and 251.3 kg N km−2 in burial of biodeposits to sediments. Nitrogen is also physically transported out of the estuary via harvest of oysters. Commercial harvest of oysters in the Mission-Aransas Estuary can remove approximately 21,665 kg N per year via physical transport from the system. We developed a transferable method to value the service of nitrogen regulation by oysters, where the potential cost equivalent value of nitrogen regulation is quantified via cost estimates for a constructed biological nutrient removal (BNR) supplement to a wastewater treatment plant. The potential annual engineered cost equivalent of the service of nitrogen regulation and removal provided by reefs in the Mission-Aransas Estuary is $293,993 yr−1. Monetizing ecosystem services can help increase awareness at the stakeholder level of the importance of oysters beyond commercial fishery values alone.
A Socio-ecological Imperative for Broadening Participation in Coastal and Estuarine Research and Management
(Estuaries and Coasts, 2022-05-18) Harris, L.A.; Grayson, T.; Neckles, H.A.; Emrich, C.T.; Lewis, K.A.; Grimes, K.W.; Williamson, S.; Garza, C.; Whitcraft, C.R.; Pollack, Jennifer Beseres; Talley, D.M.; Fertig, B.; Palinkas, C.M.; Park, S.; Vaudrey, J.M.P.; Fitzgerald, A.M.; Quispe, J.
For most of the scientific disciplines associated with coastal and estuarine research, workforce representation does not match the demographics of communities we serve, especially for Black, Hispanic or Latino, and Indigenous peoples. This essay provides an overview of this inequity and identifies how a scientific society can catalyze representational, structural, and interactional diversity to achieve greater inclusion. Needed changes go beyond representational diversity and require an intentional commitment to build capacity through inclusivity and community engagement by supporting anti-racist policies and actions. We want to realize a sense of belonging on the part of scientists in society at large and enable research pursuits through a lens of social justice in service of coastal communities. Minimally, this framework offers an avenue for increased recruitment of individuals from more diverse racial and ethnic identities. More broadly, the mechanisms described here aim to create a culture in scientific societies in which social justice, driven by anti-racist actions, produces systemic change in how members of scientific societies approach, discuss, and address issues of inequity. We have written this essay for members of the coastal and marine science community who are interested in change. We aim to call in new voices, allies, and champions to this work.
Using epibenthic fauna as biomonitors of local marine contamination adjacent to McMurdo Station, Antarctica
(Marine Pollution Bulletin, 2022-05) Palmer, Terence; Klein, Andrew; Sweet, Stephen; Frazier, Amanda; Montagna, Paul; Wade, Terry; Pollack, Jennifer Beseres
Ten benthic fauna taxa in a polluted marine area adjacent to McMurdo Station, Antarctica were deemed to be potential biomonitors because PCBs, DDTs, PAHs, copper, lead and/or zinc in their tissues were significantly higher than in tissues of taxa living in reference areas (p < 0.05). Concentrations of PCBs and DDT were highest in Trematomus (fish). Total PAH concentrations were highest in Alcyonium antarcticum (soft coral), Isotealia antarctica (anemone) and L. elliptica. Copper and lead concentrations were highest in Laternula elliptica (bivalve) and Flabegraviera mundata (polychaete), and lowest in Trematomus and Parbolasia corrugatus (nemertean). However, copper concentrations were even higher in the asteroids Perknaster fuscus antarcticus, Odontaster validus and Psilaster charcoti. Bioaccumulation factors for different species were highest for PCBs and DDT, and lowest for lead. Bioaccumulation of some contaminants are likely prevalent in benthic taxa at McMurdo Station, but concentrations are usually low relative to human consumption standards.

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