Paul A. Montagna

• Ph.D. U South Carolina 1983
• Endowed Chair at Texas A&M University – Corpus Christi

This paper identifies the top-50 priority questions for meiofaunal research, highlighting their critical roles in biogeochemical cycles and biodiversity. It calls for a balanced research agenda, international cooperation, and advances in technology to overcome current challenges and unlock meiofauna’s full potential.

Coastal wetlands rely on freshwater inflow for two reasons: the water itself that is needed by plant foundation species and the sediment that helps to build wetland habitats. There is a climatic gradient along the Texas coast with decreasing rain and inflow from the northeast to the southwest. Along this gradient, the percentage contribution of fre...

Interest in developing freshwater inflow needs or standards for Texas estuaries occurred in three eras over a 50-year period. In 1967, the concept that water is needed for preservation of bays and estuaries was first proposed. In 1975, the first law was enacted to study effects of freshwater inflow on estuaries. In the 1980s, the first detailed fre...

While freshwater inflow (FWI) needs for the maintenance of estuary health have long been acknowledged, environmental flow standards or, specifically, FWI standards are still uncommon. Where they exist, they are rapidly evolving over time. Texas, USA, has been working on this problem since the 1960s. Through several iterations, the legal and regulat...

The Texas coast climatic gradient of decreasing precipitation and freshwater inflow from northeast to southwest shapes estuarine ecosystems and biodiversity. By employing broad-scale diversity and community structure metrics and habitat suitability models of key indicator species, this study explored how multiple abiotic environmental factors, fres...

Patterns of freshwater inflow and salinity are presented for the Sabine-Neches, Trinity-San Jacinto, Colorado-Lavaca, Guadalupe, Mission-Aransas, Nueces, and Laguna Madre estuaries of Texas. There is a strong precipitation gradient from west to east, which translates into a strong freshwater inflow gradient where estuary inflows generally increase...

This chapter addresses the connections between long-term trends in climate variability, freshwater inflow dynamics, and salinity patterns and their effects on Perkinsus marinus infection of eastern oysters ( Crassostrea virginica ) at local and regional scales in Texas estuaries. Salinities were highest during droughts compared to normal and wet cl...

Productivity in estuaries is dependent upon nutrient influx and cycling. However, increasing urbanization and socioeconomic activities continue to influence nutrient dynamics and thus estuarine organisms. The western Gulf of Mexico coast lies in a climatic gradient that drives differences in hydrology among Texas estuaries providing a natural exper...

Rivers deliver sediments, organic matter/carbon, contaminants, and nutrients from watersheds. Sediments form delta, estuarine, marsh, and wetland habitats. Most of the sediments are derived from weathered rocks that are transported by rivers during floods as both bedload (sand and gravel) and suspended load (silts and clays, i.e., mud). Siliciclast...

Benthic organisms are ideal bioindicators of freshwater inflow effects in bays and estuaries because they are fixed in space and integrate ephemeral processes in the overlying water column over long periods of time. Freshwater inflow regulates water quality, which drives benthic abundance, productivity, diversity, and community structure. Texas est...

Meiofauna can act as remediation organisms by stimulating microphytobenthos, sequestering carbon dioxide, and degrading organic debris. Sediments from two basins in Lake Mariut, Egypt, which had undergone multiple rounds of restoration, were used in microcosm experiments to assess the role of meiofauna in organic matter degradation. Treatments incl...

Meiofauna-a collective term to define microscopic animals-represent a numerically important component of biodiversity in most of Earth's ecosystems and play a crucial role in biogeochemical cycles. Meiofauna have also been used as models to understand fundamental adaptive processes, have contributed to a better understanding of the animal's Tree of...

Until the 1960s, Lake Maruit was one of Egypt's most productive coastal brackish lakes. Continuous polluted discharge from Alexandria city resulted in long-term deterioration. The Egyptian government started a lake restoration program in 2010. Biological linkages between pelagic and benthic communities were assessed in November 2012 using parasitis...

The 2010 Deepwater Horizon (DWH) oil well blowout in the Gulf of Mexico (GoM) was the largest and perhaps most consequential accidental marine oil spill in global history. This paper provides an overview of a Research Topic consisting of four additional papers that: (1) assemble time series data for ecosystem components in regions impacted by the s...

Humans have used, and had effects on, marine ecosystems throughout history. As the human population and its economic activities increase, these effects intensify. Yet, our awareness and understanding of the long‐term, pervasive effects of anthropogenic disturbances on the seafloor, and the resident meiofauna, is far from complete. This chapter summ...

The coastal lake, Maruit, was one of the most productive coastal ecosystems in Egypt until the 1960s. It experienced long-term deterioration due to continuous discharge of pollutants from Alexandria city into its basins. The Egyptian government started a restoration program in 2010 to divert pollution sources away from the lake. Samples were collec...

Hurricanes disturb marine ecosystems by abrupt changes in storm-surge, erosion, freshwater inflow, material loads, or water quality. Hurricane Harvey (25 August 2017) was a Category 4 storm that entered the south Texas, USA, coast and produced a large flood in San Antonio Bay. Benthic abundance, biomass, and diversity have been measured quarterly a...

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 perio...

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 ichthyo-plankton samples. Sediment became sandier over time (48 to 75%) and away from the di...

In the northwestern Gulf of Mexico (nwGOM), the coastal climate shifts abruptly from the humid northeast to the semiarid southwest within a narrow latitudinal range. The climate effect plays an important role in controlling freshwater discharge into the shallow estuaries in this region. In addition to diminishing freshwater runoff down the coast, e...

Field studies showed that benthic macrofauna and meiofauna abundances increased with sediment oil concentration in areas affected by the Deepwater Horizon (DWH) oil spill. Benthic invertebrate biomass shows a dome-shaped relationship with respect to petrogenic hydrocarbon concentrations suggesting a positive effect on biomass at low-to-medium oil c...

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)....

As coastal areas become more vulnerable to climatic impacts, the need for understanding estuarine carbon budgets with sufficient spatiotemporal resolution arises. Under various hydrologic extremes ranging from drought to hurricane-induced flooding, a mass balance model has been constructed for carbon fluxes and their variabilities in four estuaries...

Tropical cyclones drive coastal ecosystem dynamics, and their frequency, intensity, and spatial distribution are predicted to shift with climate change. Patterns of resistance and resilience were synthesized for 4138 ecosystem time series from n = 26 storms occurring between 1985 and 2018 in the Northern Hemisphere to predict how coastal ecosystems...

Tropical cyclones drive coastal ecosystem dynamics, and their frequency, intensity, and spatial distribution are pre- dicted to shift with climate change. Patterns of resistance and resilience were synthesized for 4138 ecosystem time series from n = 26 storms occurring between 1985 and 2018 in the Northern Hemisphere to predict how coastal ecosyste...

Localized contamination from research-related activities and its effects on macrofauna communities in the marine environment were investigated at Palmer Station, a medium-sized Antarctic research station. Relatively low concentrations of polycyclic aromatic hydrocarbons (PAHs; 32–302 ng g ⁻¹ ) and total petroleum hydrocarbons (TPHs; 0.9–8.9 μg g ⁻¹...

There 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...

Regulatory standards for environmental flows to estuaries are not common, but they are required in Texas. This has led to adoption of complex freshwater inflow regimes that reflect seasonal and yearly fluctuations that vary geographically throughout the state. The flow regimes are based on dilution of saline water with fresh water in whole systems....

ID 685153 Because of death and gravity, the bottom of the sea is the memory of the ecosystem, where a record of all past events can be found as you move into deeper layers of sediment. Thus, benthos are primary indicators for environmental assessments. As hydrocarbon exploration and production moved to deeper waters, so did environmental studies. B...

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 concent...

Chance and good luck led to a career studying how freshwater inflow drives estuary processes. In 1986, someone asked me: How much fresh water has to flow to a bay for it to be healthy? The question shaped my career. There is probably no better place on Earth to compare effects caused by inflow differences than the Texas coast, because the major est...

The Deepwater Horizon (DWH) oil spill significantly impacted the northern Gulf of Mexico (nGoM) deep benthos (>125 m water depth) at different spatial scales and across all community size and taxa groups including microbes, foraminifera, meiofauna, macrofauna, megafauna, corals, and demersal fishes. The resilience across these communities was heter...

Tropical cyclones represent a substantial disturbance to water quality in coastal ecosystems via storm surge, winds, and flooding. However, evidence to date suggests that the impacts of tropical cyclones on water quality are generally short-lived (days-months) and that the magnitude of the disturbance is related to proximity to storm track. Discret...

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 concurr...

Nutrient budgets in semi-arid estuaries, with ephemeral freshwater inflows and limited nutrient sources, are likely incomplete if contributions from submarine groundwater discharge (SGD) are not included. Here, the relative importance of saline/recirculated SGD-derived nutrient fluxes spatiotemporal variability to the overall nutrient budget is qua...

The 2010 Deepwater Horizon blowout off the coast of Louisiana caused the largest marine oil spill on record. Samples were collected 2–3 months after the Macondo well was capped to assess damage to macrofauna and meiofauna communities. An earlier analysis of 58 stations demonstrated severe and moderate damage to an area of 148 km². An additional 58...

in the Northern Gulf of Mexico and resulted in a deep-sea plume of petroleum hydrocarbons and a marine oiled snow sedimentation and flocculent accumulation (MOSSFA) event. It is hypothesized that recovery will occur when the contaminated sediment is buried below the biologically active zone of 10 cm. Recovery rate can be inferred from the similar I...

Tropical cyclones play an increasingly important role in shaping ecosystems. Understanding and generalizing their responses is challenging because of meteorological variability among storms and its interaction with ecosystems. We present a research framework designed to compare tropical cyclone effects within and across ecosystems that: a) uses a d...

Tropical cyclones are major disturbances for coastal systems. Hurricane Harvey made landfall in Texas, USA, on August 25, 2017 as a category 4 storm. There were two distinct disturbances associated with this storm that were spatially decoupled: (1) high winds causing direct damage and storm surge, and (2) high rains causing scouring floods and sign...

Oil from the Deepwater Horizon blowout reached the seafloor through deep-sea plumes and sedimentation of oil and oiled marine snow. This oil caused extensive damage over wide areas to both hard-bottom and soft-bottom communities. The most sensitive bioindicators were deep-sea planar octocorals for hard-bottoms and macrofauna and meiofauna diversity...

The Deep Gulf of Mexico Benthos (DGoMB) program was designed to determine patterns of abundance and diversity of meiofauna and macrofauna in the northern Gulf of Mexico continental slope between 300 m and 3700 m depth. Abundance of all taxa was significantly influenced by the particulate organic carbon (POC) flux. The abundance of meiofauna, macrof...

This chapter provides a comparison between recently developed, post-oil spill baseline measurements throughout the Gulf of Mexico (GoM) and previous, pre-oil spill baselines for benthic foraminifera, meiofauna, and macrofauna for areas impacted by the Deepwater Horizon (2010) and Ixtoc 1 (1979–1980) oil spills. This comparison will provide two prim...

During an oil spill, a marine oil snow sedimentation and flocculent accumulation (MOSSFA) event can transport oil residue to the seafloor. Microcosm experiments were used to test the effects of oil residues on meiofaunal abundance and the nematode:copepod ratio under different oil concentrations and in the presence and absence of marine snow. Total...

The book was inadvertently published without including the name of Michael G. Reuscher as a co-author of Chapter 5.

The present article provides water quality data collected from three South Texas Estuaries (Guadalupe, Nueces and Lavaca-Colorado Estuaries) during frequent drought from 2011 to 2014. The data described here are presented in the research article "The relationship between suspended solids and nutrients with variable hydrologic flow regimes" Paudel e...

The hypothesis that “freshwater inflow variability over space and time can drive suspended solids and nutrient concentrations” was tested by comparing three micro-tidal estuaries (Guadalupe, Lavaca-Colorado, and Nueces) in Texas with different hydrologic flow regimes over three years with wet and dry conditions. In all three estuaries, Total suspen...

The ocean floor is covered by sediments, thus marine benthos is one of the largest single habitats on Earth. Yet, the total area of sediment habitat that has been sampled is infinitesimally small. This is likely because the main method to sample the bottom relies on single point samplers such as grabs and cores. Larger areas are sampled by dragging...

The offshore and deep-sea marine environment provides many ecosystem services (i.e., benefits to humans), for example: climate regulation, exploitable resources, processes that enable life on Earth, and waste removal. Unfortunately, the remote nature of this environment makes it difficult to estimate the values of these services. One service in par...

Given projected changes in river flow to coastal regions worldwide due to climate change and increasing human freshwater demands, it is necessary to determine the role hydrology plays in regulating the biogeochemistry of estuaries. A climatic gradient exists along the Texas coast where freshwater inflow balance ranges from hydrologically positive t...

There are thousands of seeps in the deep ocean worldwide; however, many questions remain about their contributions to global biodiversity and the surrounding deep‐sea environment. In addition to being globally distributed, seeps provide several benefits to humans such as unique habitats, organisms with novel genes, and carbon regulation. The purpos...

Construction of two dams on the Nueces River reduced environmental flow to the Nueces Marsh causing ecosystem degradation. A pipeline was built to enhance flows and restore hydrological connections between the river and marsh. Sediment and water quality has been monitored in Rincon Bayou since the pipeline was operational in 2009. Hydrologically, R...

Environmental flows describe the quality, quantity, and timing of freshwater inflows required to maintain the components, functions, processes, and resilience of downstream bay and estuarine resources. Knowledge of how estuarine resources relate to the condition of an estuary enables resource managers to determine optimal freshwater inflows for tar...

A pipeline to pump water from the Nueces River to the upper delta at Rincon Bayou was constructed to mitigate the reduction of inflow from impoundments. Pumping has restored ecological function to the Nueces Estuary by increasing inflow and decreasing salinity, and transitioned the marsh into a positive estuary (lower salinities upstream increasing...

Project Goal, Significance, Rationale Goal: A policy analysis of the SB3 process for environmental flows for each of the bay/basin systems. Significance: This research proposes to: Examine how a specific law and the related policies are actually operating to manage freshwater inflows into Texas bays and estuaries. This research proposes a complete...

Recent research revealing the extent of marine habitat degradation has ignited a surge of restoration efforts globally. Restoration of estuarine habitats became a priority in the United States with the Estuary Restoration Act (ERA) of 2000. In the present study, a synthesis of data from the National Estuaries Restoration Inventory (NERI), developed...

Water resource development has decreased water delivery to marshes in the Nueces Delta, Corpus Christi, Texas, USA by 45% since 1983, which has led to marsh degradation. Recent management actions will allow for partial hydrological restoration of the marsh, but there is a need to understand the dynamics and the interactive roles of climate and wate...

Short oral presentation for The TAMU-CC Marine Science Graduate Student Organization 7th Annual Research Forum.

The Deepwater Horizon oil spill occurred in spring and summer 2010 in the northern Gulf of Mexico. Research cruises in 2010 (approximately 2–3 months after the well had been capped), 2011, and 2014 were conducted to determine the initial and subsequent effects of the oil spill on deep-sea soft-bottom infauna. A total of 34 stations were sampled fro...

The impacts of the 2010 Deepwater Horizon (DWH) disaster on deep-sea Gulf of Mexico benthic communities were analyzed one year after the blowout. Richness, diversity, and evenness were severely impaired within a radius of approximately 1 km around the DWH wellhead. However, lower diversity than background was observed in several stations up to 29 k...

Gulf Coast communities and natural resources suffered extensive direct and indirect damage as a result of the largest accidental oil spill in US history, referred to as the Deepwater Horizon (DWH) oil spill. Notably, natural resources affected by this major spill include wetlands, coastal beaches and barrier islands, coastal and marine wildlife, se...

Studies of estuarine eutrophication have tended to focus on systems with continually flowing rivers, while little is known about estuaries from semi-arid/arid regions. Here we report results from an assessment of water quality conditions in Baffin Bay, Texas, a shallow (<2–3 m) subtropical estuary located in a semi-arid region that has agriculture...

Paired sediment contaminant and benthic infaunal data from prior studies following the 2010 Deepwater Horizon (DWH) oil spill in the Gulf of Mexico were analyzed using logistic regression models (LRMs) to derive sediment quality benchmarks for assessing risks of oil-related impacts to the deep-sea benthos. Sediment total polycyclic aromatic hydroca...

The purpose of the present study was to compare the nature of dissolved inorganic nitrogen (DIN = ammonium (NH4⁺) and nitrite + nitrate (NO2+3 = (NO2– + NO3–)) release from aerobic sediment slurry at two different hydrologic flow regimes. The watershed of the Guadalupe River–Estuary system receives more freshwater inflow than does the watershed of...

The effect of the Deepwater Horizon oil spill on benthic macrofauna in the deep-sea Gulf of Mexico was measured in September–October 2010. Macrofauna community diversity and abundance were lowest closest to the wellhead and increased with distance from the wellhead up to 10 km. The macrofauna loss was primarily in surface sediments, which could be...

A need in environmental science is to determine the response range of a bioindicator to environmental drivers. A common problem with regression based approaches is the indicator response may be obfuscated by many zero or low-value observations when the organisms are not present because of life history characteristics. A method is described for dete...

Sampling methods for benthic meiofauna and macrofauna assessments on the northern Gulf of Mexico continental slope and deep sea were compared. For meiofauna, a core with an inner diameter of 5.1 cm is recommended for yielding an appropriate sample size. Meiofauna are concentrated in the uppermost 2 cm sediment layer, so the top 3 cm are sufficient...

Approximately 90% of the volume of the Gulf of Mexico is contained in water deeper than 200 m, a region where the Deepwater Horizon (DWH) blowout had more impact on ecosystems than any previous oil spill. The remoteness and relative inaccessibility of the deep sea makes documenting even acute impacts to the animals that live in this realm difficult...

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 pre...

In fall 2010, several months after the Deepwater Horizon blowout was capped, zones of moderate and severe impacts to deep-sea, soft-bottom benthos were identified that together extended over an area of 172 km2. A subset of stations sampled in 2010 was resampled in May and June 2011, 10 to 11 months after the event, to determine whether the identifi...

The Nueces River Basin is one of the 15 major river basins in Texas, and is an important water supply for the Nueces-Rio Grande Coastal Basin area. The construction of two large reservoir dams in the Nueces River Basin has reduced the amount of freshwater reaching the Nueces Estuary by 99% from that of its historical flows. The reduction of freshwa...

To investigate effects of watershed nutrient loadings on estuarine responses, we analyzed historical data from the Lower San Antonio and Guadalupe River Watersheds, Texas, USA, and developed a generic ecosystem model. Twenty-one years (1976 - 1997) of historical water quality data were obtained from the Texas Commission on Environmental Quality (TC...

Freshwater inflow is a driver of the functioning of estuaries, and average salinity is usually measured to identify the effects of inflow in salinity-zone habitats. However, salinity variability could act as a disturbance by producing unstable habitats, leading to the question: is salinity variance an indicator of benthic disturbance, and therefore...

South Texas has a semi-arid climate with a large interannual variability of freshwater inflows. This study sought to define how changes in freshwater inflow affect the composition, quantity and quality of suspended particulate organic matter (SPOM) in a South Texas estuary: the Mission-Aransas estuary. The study was implemented 1.5 months after a l...

Enhanced water quality and nutrient regulation via oyster filtration are commonly cited goals of oyster reef restoration projects. Monitoring often involves sampling of oysters and water column organic matter (e.g., chlorophyll-a), and nutrient regulating ecosystem services are typically quantified via filtration rate models. However, in shallow, w...

Florida legislation requires determining and implementing an appropriate range and frequency of freshwater inflows that will sustain a fully functional estuary. Changes in inflow dynamics to the Caloosahatchee Estuary, Florida have altered salinity regimes which in turn have altered the ecological integrity of the estuary. The purpose of this curre...