Technical Reports
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Item Long-term Trends in Lavaca-Colorado and Guadalupe Estuaries(2022-12-21) Montagna, PaulThe purpose of the current project was to determine if the long-term decline in bottom-dwelling invertebrates are still occurring and if pollution from the Formosa discharge into Lavaca Bay may be the cause of the decline if it is still occurring. The primary focus was on water and sediment quality of the Lavaca Bay ecosystem. Four tasks were performed: 1) Analyzed archived benthic samples. 2) Synthesized existing monitoring data from the Texas Parks and Wildlife Department, Coastal Fisheries Program (TPWD). 3) Synthesized existing water and sediment quality monitoring data of the Formosa Plastics Corporation discharge site into Lavaca Bay. 4) Data management, reporting, and outreach. In the long-term benthic dataset, the bay systems have different long-term characteristic fauna that reflects the long-term average salinity conditions in each bay system. The Lavaca-Colorado Estuary has on average about 37% more inflow than the Guadalupe Estuary, and 11 times more than the Nueces Estuary. San Antonio Bay is small and limited exchange with the Gulf of Mexico, therefore it has lower long-term average salinity than Lavaca Bay. The San Antonio Bay community has a higher contribution of mollusks, which are freshwater indicators, than Lavaca Bay, and much higher than Nueces Bay. Within the estuary systems, the secondary bays have distinct communities compared to the primary bays. This is because secondary bays are closer to freshwater inflow sources and are more oligohaline and/or brackish in nature than primary bays, which are more marine influenced. In the Formosa dataset, 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. There is an inconsistency between the HRI and Formosa benthic data, in that the HRI data is still declining, but the Formosa data has remained constant over time. Similar trends are true for the TPWD trawl data and the Formosa trawl data. In conclusion, 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 3,810 meters 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.Item Report 1: Water Quality, Benthic Macrofauna, and Epibenthic Fauna(2014-03) Montagna, P.A.; Palmer, T.A.Item Long-Term Benthic Data: Adaptive Management of Three Basins(2022-05) Montagna, Paul A.Item Vulnerability Assessment of Coastal Bend Bays(2021-12) Montagna, Paul A.; Coffey, Daniel M.; Jose, Rafael H.; Stunz, Gregory W.Item Evaluation of the Proposal for Widening and Deepening the Matagorda Ship Channel(2021-09) Montagna, Paul A.; Gibeaut, James C.; Dotson, Marissa; Douglas, Audrey R.; Magolan, Jessica; Palacios, Juan M.; Rener, Lauren; Subedee, Mukesh; Trevino, KarinThere is a proposal for deepening and widening the Matagorda Ship Channel. However, there are concerns about specific environmental impacts to Matagorda Bay and Lavaca Bay such as: 1) Circulation and storm surge changes due to changing the bathymetry of Matagorda and Lavaca Bays due to deepening the channel and placement of dredge spoil parallel to the channel, which will funnel tidal movement along the axis of the bay and restrict mixing perpendicular to the channel. 2) Salinity changes due to the circulation changes and connecting with the puncturing of the groundwater lens beneath the bay. 3) Placement of dredge spoil could smother benthic habitats, such as oysters, seagrasses, or muddy bay bottoms and affect forage for desirable fish species. 4) Effects to primary producers or bottom dwelling organisms due to an increase in turbidity during the actual dredging. 5) Mobilization of mercury by the dredging because there are considerable amounts of mercury in sediments of the bay. 6) Plastic and microplastics interactions with sediments, turbidity, and other pollutants. The current study was undertaken to assess these possible concerns. The assessment has been done in two parts to identify potential physical and ecological effects. The assessments were based on a literature review of existing information. No sampling was conducted.Item Workshop Report: Freshwater Inflow to Texas Bays and Estuaries(2021-08) Montagna, Paul A.; Douglas, Audrey R.Item Assessment of the Relationship Between Freshwater Inflow and Biological Indicators in Lavaca Bay(2020-12) Montagna, Paul A.; Cockett, Patricia Malamalama; Kurr, Elaine M.; Trungale, JoeItem Using Comparative Long-term Benthic Data for Adaptive Management of Freshwater Inflow to Three Basins(2020-01) Montagna, Paul A.; Cockett, Patricia Malamalama; Lupher, Melissa RohalItem RAPID: Capturing the Signature of Hurricane Harvey on Texas Coastal Lagoons(2019) Montagna, Paul A.; Hu, Xinping; Wetz, Michael S.Item The Hydrological Switch: A Novel Mechanism Explains Eutrophication and Acidification of Estuaries(2019-09) Montagna, Paul A.; Hu, Xinping; Wetz, Michael S.; Byrne, Robert; Liu, Zhanfei; Kim, Hae-CheolItem Management Strategies for the Rincon Bayou Pipeline(2019-01) Montagna, Paul A.Decreased inflow due to damming of the Nueces and Frio rivers has resulted in increasing salinity in Nueces Bay and caused Rincon Bayou to become a reverse estuary disturbing the overall hydrology of the adjacent Corpus Christi Bay. Adaptive management to perform hydrological restoration began in 1994 and continues today. The objective of the present study is to develop a set of recommendations and implementation strategy for management of environmental flows delivered to upper Rincon Bayou by the Rincon Bayou Pipeline. This information is needed to improve the environmental effectiveness of pumped flow deliveries to Rincon Bayou and the Nueces marsh. Change in water quality and benthic community structure were used as indicators of ecological effects. High inflow reduces salinity and introduces nutrients. Large and haphazard salinity fluctuations result in an often disturbed system populated by pioneer species, such as chironomid larvae and the polychaete Streblospio benedicti, during especially low and high salinity periods. Epifaunal organisms are mobile and capable of escaping unsuitable conditions, so the more immediate results of fluctuations in water quality is the lack of higher trophic marine organisms following pumping events. Results of time lags indicated that variance in diversity variables in response to changes in salinities occurred within the first few weeks after pumping. Immediate responses to salinity were not identified in abundance and biomass. Positive relationships between abundance and biomass, in response to salinity fluctuations, were evident after 6 to 8 weeks. A little bit of water pumped during dry times can have positive environmental benefits, and too much water pumped during wet times can have a negative influence and act as an ecological disturbance. The results of the infaunal and epifaunal analyses indicate that further changes need to be made to the Rincon Bayou restoration and management programs in order to reestablish a reasonably undisturbed ecosystem.Item Management Strategies for the Rincon Bayou Pipeline(2018-06) Montagna, Paul A.Item Conceptual Model of Effects of Reduced Freshwater Inflow in the Anahuac National Wildlife Refuge(2017-06) Montagna, Paul A.; Morgan, ElaniItem Monitoring Mid-Coastal Estuaries - 2016(2017-12) Montagna, Paul A.; Wetz, Michael S.; Hu, XinpingIn recognition of the importance that the ecological soundness of our riverine, bay, and estuary systems and riparian lands has on the economy, health, and well-being of our state, the 80th Texas Legislature enacted Senate Bill 3 (SB3, 2007), which requires an ecosystem management approach to provide environmental flows “adequate to support a sound ecological environment and to maintain the productivity, extent, and persistence of key aquatic habitats.” Thus, there is a continued need for monitoring information about freshwater inflow effects on water and sediment quality and biological indicator communities to provide adaptive management of environmental inflow standards for Texas estuaries. The purpose of the present study is to extend the long-term biological collection of benthic data in San Antonio Bay (Guadalupe Estuary), Lavaca and Matagorda Bays (Lavaca-Colorado Estuary), and Nueces and Corpus Christi Bays (Nueces Estuary). Bottom-dwelling organisms are ideal bioindicators of freshwater inflow effect on bays and estuaries because they are fixed in space, and integrate ephemeral processes in the over-lying water column over long periods of time. Only benthic samples from the Guadalupe Estuary have been analyzed, and the benthic data has demonstrated that long-term hydrological cycles, which affect freshwater inflow and water quality, also regulate benthic abundance, productivity, diversity, and community structure. In addition, changes in water quality due to inflow variability were measured in all three estuaries, including chlorophyll (as an indicator of primary production), inorganic nutrients, dissolved and particulate organic matter (DOM and POM), and the carbonate system variables alkalinity, dissolved inorganic carbon (DIC), and pH. The estuaries respond rapidly to freshwater inflow variability, displaying higher inorganic nutrient and chlorophyll concentrations during high inflow, low salinity conditions. Dissolved organic carbon and nitrogen concentrations were consistently high in the estuaries, providing an important source of matter fueling microbial growth. The dissolved organic matter concentration was influenced by freshwater inflow variability in Lavaca-Colorado and Nueces Estuaries, but not in the Guadalupe Estuary. Carbonate saturation state, an important indicator for the suitability of calcifying organisms (shellfish etc.), changed with both river endmember chemical composition and the extent of freshwater inflow. The northern Lavaca-Colorado Estuary showed carbonate undersaturation following a significant freshwater discharge period, although the southern estuaries were less influenced by the hydrological change.Item Restoration in Place Strategy for the Deep-sea Soft-Bottom Benthos: Long-term Monitoring to Support Restoration Efforts(2017-05) Montagna, Paul A.; Baguley, Jeffrey G.; Cooksey, CynthiaItem Effect of Freshwater Inflow on Habitat Suitability Change in Texas Bays(2016-11) Turner, Evan L.; Savage, Kelley; Trungale, Joe; Palmer, Terence A.; Montagna, Paul A.Freshwater inflow is critically important for foundational estuarine invertebrate species such as the Eastern Oyster, Crassostrea virginica. This empirical study tests the viability of the proactive management strategy of the release of supplementary freshwater inflow into two Texas bays to increase oyster health. An oyster habitat suitability index was created through regression analyses to test the effect of altered inflows. We demonstrate the inflow requirement to lower salinities from base marine (35 PSU) conditions to polyhaline (25 PSU) conditions is possible within human release activities if directed in Tres Palacios Bay and Caranacahua Bay, Texas. Even small inflow supplements such as 1,500 acre-ft of additional freshwater added during the summer months can enhance oyster health. This health improvement is due to lowering the risk of the oyster parasite Perkinsus marinus (Dermo) prevalance by decreasing salinities to between 20 and 25 PSU.Item The Effect of the Deepwater Horizon Oil Spill on Human Wellbeing in the Gulf of Mexico(2016-09) Montagna, Paul A.; Yoskowitz, David; Carrollo, ChristinaIt’s always important in environmental assessment to be able to understand how an event has an effect on people. The only way to do that is to translate biophysical impacts to ecosystem service impacts. This approach was taken in order to determine how the Deepwater Horizon (DWH) blowout impacted ecosystem services in the Gulf of Mexico. An Ecopath with Ecosim model was developed for the Northern Gulf of Mexico that incorporated three ecosystem services: commercial fisheries, recreational fisheries, and carbon sequestration. The model predicted an overall decrease in all three services investigated. Changes in commercial fisheries and carbon sequestration were valued by linking the model outputs to monetary valuation models. With regards to commercial fisheries the change in fisheries yield resulted in monetary changes ranging from $65 to -$5,091,109 in one year. Investigation of carbon sequestration predicted up to an $876,583 loss in the ability of the Northern Gulf of Mexico offshore environment to sequester carbon. This project has provided the first estimates of ecosystem services in an offshore environment and evaluated their changes as a result of DWH accident.Item Vallisneria americana’s physiological responses to change in salinity(2016-08) Chaloupka, Crystal; Montagna, Paul A.Item Effects on Benthic Macrofauna from Pumped Flows to Rincon Bayou(2016-08) Montagna, Paul A.; Chaloupka, Crystal; Del Rosario, Elizabeth; Gordon, Amanda; Turner, Evan L.Decreased inflow due to damming of the Nueces and Frio rivers has resulted in increasing salinity in Nueces Bay and caused Rincon Bayou to become a reverse estuary disturbing the overall hydrology of the adjacent Corpus Christi Bay. Adaptive management to perform hydrological restoration began in 1994 and continues today. The objectives of the present study are to determine to what extent salinity fluctuates within Rincon Bayou and what effects these fluctuations have on estuary health. Benthic infauna are ideal indicators of ecological effects because of their relative immobility and longevity in contrast with plankton of comparable size. Nearly all past studies focused on benthic infauna, here we add measurements of benthic epifauna, which are larger, more mobile invertebrates and represent a higher trophic level. Archived samples were analyzed as well as new samples collected from the upper Rincon Bayou near Corpus Christi, TX. For macroinfaunal, one historical station (C) was sampled biweekly and two historical stations (F and G) were sampled quarterly. For epifauna, all three stations were sampled biweekly. Conductivity, temperature, and salinity were monitored continuously. Additional water column measurements were taken during sampling events. Macrofauna and epifauna biomass, abundance, and diversity were recorded and analyzed. High inflow reduces salinity and introduces nutrients. Large and haphazard salinity fluctuations result in an often disturbed system populated by pioneer species, such as chironomid larvae and the polychaete Streblospio benedicti, during especially low and high salinity periods. Epifaunal organisms are mobile and capable of escaping unsuitable conditions, so the more immediate results of fluctuations in water quality is the lack of higher trophic marine organisms following pumping events. Results of time lags indicated that variance in diversity variables in response to changes in salinities occurred within the first few weeks after pumping. Immediate responses to salinity were not identified in abundance and biomass. Positive relationships between abundance and biomass, in response to salinity fluctuations, were evident after 6 to 8 weeks. The results of the infaunal and epifaunal analyses indicate that further changes need to be made to the Rincon Bayou restoration and management programs in order to reestablish a reasonably undisturbed ecosystem.Item Determining Optimal Pumped Flows to Nueces Delta(2016-07) Montagna, Paul A.; Adams, Leslie; Chaloupka, Crystal; Del Rosario, Elizabeth; Kalke, Richard D.; Turner, Evan L.