Geology topics

Research about Mississippi

Source-linked reports with geographic coverage including Mississippi.

At least 91 records · Page 5Linked to original sources

USGS2014

U.S. Geological Survey unconventional petroleum systems research in south Mississippi: Observations on burial history and thermal maturity in the Cretaceous

Shale hydrocarbon ‘resource’ plays have revolutionized the United States energy mix over the last 5 years. These plays are diverse in lithology and age but share the common feature of occurring in ‘tight’ formations which require hydraulic (hydro-) fracturing for economic flow rates. In general, economic success requires an organic-rich reservoir with a quartz- or carbonate-rich mineralogy that responds to artificial stimulation by fracturing. The U.S. Geological Survey (USGS) is tasked with estimating the quantity and quality of undiscovered hydrocarbons reservoired in shales. In support of that mission, we began an investigation of unconventional petroleum systems in the southern part of the Mississippi Salt Basin in 2012, building on earlier reconnaissance work that identified this area as potentially prospective for ‘shale’ gas (Enomoto et al., 2012). While our recent studies (Valentine et al., 2014a; Hackley et al., 2014) have suggested poor ‘shale’ gas prospectivity (due to low organic content, low porosity, high clay content, and significant depth), at least for the Aptian section, they also have generated a wealth of new information about thermal maturity in the Cretaceous of south Mississippi. In addition, our work to-date has set the stage for future USGS evaluation of unconventional hydrocarbons reservoired in the Upper Cretaceous Tuscaloosa Marine Shale (TMS). Here, we summarize recent USGS thermal maturity studies in the south Mississippi Salt Basin.

Mississippi↗

USGS2013

Site preparation for switchgrass intercropping in loblolly pine plantations reduces retained trees and snags, but maintains downed woody debris

Within young pine ( Pinus spp.) plantations, coarse woody debris (CWD) and green trees are important habitat structures that may be impacted by the production of biofuel feedstock. Therefore, we compared site preparation procedures associated with switchgrass ( Panicum virgatum L.) intercropping to determine effects on CWD and green trees in stands ( n = 24) site-prepared for intercropping, with switchgrass only, or pine plantation in Mississippi, USA. Following site preparation, CWD dispersal or volume did not differ between intercropped and control stands. Intercropped stands had significantly fewer retained trees and snags. Switchgrass monocultures had no retained trees or piles and significantly fewer pieces and less volume of CWD than the other treatments. Our results suggest switchgrass intercropping may provide similar habitat quality to traditional pine plantations for wildlife species using these areas in the year following disturbance, but may provide a less suitable habitat for species that require snags. However, the relationship between snag reduction and wildlife population response in an intercropped setting is not clear and should be further investigated. Regardless, if retaining snags is a desired outcome, site preparation for switchgrass should be restricted to the interbed area where it will be cultivated as opposed to extensive debris removal from the entire site.

Mississippi↗

USGS2013

Reservoir floodplains support distinct fish assemblages

Reservoirs constructed on floodplain rivers are unique because the upper reaches of the impoundment may include extensive floodplain environments. Moreover, reservoirs that experience large periodic water level fluctuations as part of their operational objectives seasonally inundate and dewater floodplains in their upper reaches, partly mimicking natural inundations of river floodplains. In four flood control reservoirs in Mississippi, USA, we explored the dynamics of connectivity between reservoirs and adjacent floodplains and the characteristics of fish assemblages that develop in reservoir floodplains relative to those that develop in reservoir bays. Although fish species richness in floodplains and bays were similar, species composition differed. Floodplains emphasized fish species largely associated with backwater shallow environments, often resistant to harsh environmental conditions. Conversely, dominant species in bays represented mainly generalists that benefit from the continuous connectivity between the bay and the main reservoir. Floodplains in the study reservoirs provided desirable vegetated habitats at lower water level elevations, earlier in the year, and more frequently than in bays. Inundating dense vegetation in bays requires raising reservoir water levels above the levels required to reach floodplains. Therefore, aside from promoting distinct fish assemblages within reservoirs and helping promote diversity in regulated rivers, reservoir floodplains are valued because they can provide suitable vegetated habitats for fish species at elevations below the normal pool, precluding the need to annually flood upland vegetation that would inevitably be impaired by regular flooding. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Mississippi↗

USGS2013

Phosphorus losses from agricultural watersheds in the Mississippi Delta

Phosphorus (P) loss from agricultural fields is of environmental concern because of its potential impact on water quality in streams and lakes. The Mississippi Delta has long been known for its fish productivity and recreational value, but high levels of P in fresh water can lead to algal blooms that have many detrimental effects on natural ecosystems. Algal blooms interfere with recreational and aesthetic water use. However, few studies have evaluated P losses from agricultural watersheds in the Mississippi Delta. To better understand the processes influencing P loss, rainfall, surface runoff, sediment, ortho-P (orthophosphate, PO 4 –P), and total P (TP) were measured (water years 1996–2000) for two subwatersheds (UL1 and UL2) of the Deep Hollow Lake Watershed and one subwatershed of the Beasley Lake Watershed (BL3) primarily in cotton production in the Mississippi Delta. Ortho-P concentrations ranged from 0.01 to 1.0 mg/L with a mean of 0.17 mg/L at UL1 (17.0 ha), 0.36 mg/L at UL2 (11.2 ha) and 0.12 mg/L at BL3 (7.2 ha). The TP concentrations ranged from 0.14 to 7.9 mg/L with a mean of 0.96 mg/L at UL1, 1.1 mg/L at UL2 and 1.29 mg/L at BL3. Among the three sites, UL1 and UL2 received P application in October 1998, and BL3 received P applications in the spring of 1998 and 1999. At UL1, ortho-P concentrations were 0.36, 0.25 and 0.16 for the first, second and third rainfall events after P application, respectively; At UL2, ortho-P concentrations were 1.0, 0.66 and 0.65 for the first, second and third rainfall events after P application, respectively; and at BL3, ortho-P concentrations were 0.11, 0.22 and 0.09 for the first, second and third rainfall events after P application, respectively. P fertilizer application did influence P losses, but high P concentrations observed in surface runoff were not always a direct result of P fertilizer application or high rainfall. Application of P in the fall (UL1 and UL2) resulted in more ortho-P losses, likely because high rainfall often occurred in the winter months soon after application. The mean ortho-P concentrations were higher at UL1 and UL2 than those at BL3, although BL3 received more P application during the monitoring period, because P was applied in spring at BL3. However, tillage associated with planting and incorporating applied P in the spring (BL3) may have resulted in more TP loss in sediment, thus the mean TP concentration was the highest at BL3. Ortho-P loss was correlated with surface runoff; and TP loss was correlated with sediment loss. These results indicate that applying P fertilizer in the spring may be recommended to reduce potential ortho-P loss during the fallow winter season; in addition, conservation practices may reduce potential TP loss associated with soil loss.

Mississippi↗

USGS2013

Gradients of microhabitat and crappie ( Pomoxis spp.) distributions in reservoir coves

Embayments are among the most widespread littoral habitats found in Mississippi flood-control reservoirs. These macrohabitats represent commonly used nursery zones for age-0 crappies, Pomoxis spp., despite barren and eroded shorelines formed over 60–70 years of annual water level fluctuations. We tested if embayments displayed microhabitat gradients linked to the effect of water level fluctuations on riparian vegetation and if these gradients were paralleled by gradients in age-0 crappie distribution. Habitat composition changed longitudinally along the embayments with the most pronounced gradient representing a shift from nonvegetated mudflats near the mouth of embayments to herbaceous material upstream. The degree of habitat change depended on the water level. Similarly, catch rates of crappies increased upstream toward the rear of embayments, differing among water levels and reservoirs, but the longitudinal pattern persisted. Our results indicate that habitat composition gradients occur in embayments of northwest Mississippi flood-control reservoirs and that these gradients may influence a similar gradient in age-0 crappie distribution. While the biotic interactions behind the gradients may be less clear, we speculate that water level is the main factor influencing the observed gradients in habitat composition and fish. Management to benefit age-0 crappies may involve habitat improvement along embayment shorelines and water level regimes that foster growth of herbaceous plants.

Mississippi↗

USGS2013

Water levels shape fishing participation in flood-control reservoirs

We examined the relationship between fishing effort (hours fished) and average March–May water level in 3 flood control reservoirs in Mississippi. Fishing effort increased as water level rose, peaked at intermediate water levels, and decreased at high water levels. We suggest that the observed arched-shaped relationship is driven by the shifting influence of fishability (adequacy of the fishing circumstances from an angler's perspective) and catch rate along a water level continuum. Fishability reduces fishing effort during low water, despite the potential for higher catch rates. Conversely, reduced catch rates and fishability at high water also curtail effort. Thus, both high and low water levels seem to discourage fishing effort, whereas anglers seem to favor intermediate water levels. Our results have implications for water level management in reservoirs with large water level fluctuations.

Mississippi↗

USGS2013

Wetland management reduces sediment and nutrient loading to the upper Mississippi River

Restored riparian wetlands in the Upper Mississippi River basin have potential to remove sediment and nutrients from tributaries before they flow into the Mississippi River. For 3 yr we calculated retention efficiencies of a marsh complex, which consisted of a restored marsh and an adjacent natural marsh that were connected to Halfway Creek, a small tributary of the Mississippi. We measured sediment, N, and P removal through a mass balance budget approach, N removal through denitrification, and N and P removal through mechanical soil excavation. The marsh complex had average retention rates of approximately 30 Mg sediment ha −1 yr −1 , 26 kg total N ha −1 yr −1 , and 20 kg total P ha −1 yr −1 . Water flowed into the restored marsh only during high-discharge events. Although the majority of retention occurred in the natural marsh, portions of the natural marsh were hydrologically disconnected at low discharge due to historical over-bank sedimentation. The natural marsh removed >60% of sediment, >10% of P, and >5% of N loads (except the first year, when it was a N source). The marsh complex was a source of NH 4 + and soluble reactive P. The average denitrification rate for the marsh complex was 2.88 mg N m −2 h −1 . Soil excavation removed 3600 Mg of sediment, 5.6 Mg of N, and 2.7 Mg of P from the restored marsh. The marsh complex was effective in removing sediment and nutrients from storm flows; however, retention could be increased if more water was diverted into both restored and natural marshes before entering the river.

Mississippi↗

USGS2013

Benthic substrate classification map: Gulf Islands National Seashore

The 2005 hurricane season was devastating for the Mississippi Gulf Coast. Hurricane Katrina caused significant degradation of the barrier islands that compose the Gulf Islands National Seashore (GUIS). Because of the ability of coastal barrier islands to help mitigate hurricane damage to the mainland, restoring these habitats prior to the onset of future storms will help protect the islands themselves and the surrounding habitats. During Hurricane Katrina, coastal barrier islands reduced storm surge by approximately 10 percent and moderated wave heights (Wamsley and others, 2009). Islands protected the mainland by preventing ocean waves from maintaining their size as they approached the mainland. In addition to storm protection, it is advantageous to restore these islands to preserve the cultural heritage present there (for example, Fort Massachusetts) and because of the influence that these islands have on marine ecology. For example, these islands help maintain a salinity regime favorable to oysters in the Mississippi Sound and provide critical habitats for many migratory birds and endangered species such as sea turtles (Chelonia mydas, Caretta caretta, and Dermochelys coriacea), Gulf sturgeon (Acipenser oxyrinchus desotoi), and piping plovers (Charadrius melodus) (U.S. Army Corps of Engineers, 2009a). As land manager for the GUIS, the National Park Service (NPS) has been working with the State of Mississippi and the Mobile District of the U.S. Army Corps of Engineers to provide a set of recommendations to the Mississippi Coastal Improvements Program (MsCIP) that will guide restoration planning. The final set of recommendations includes directly renourishing both West Ship Island (to protect Fort Massachusetts) and East Ship Island (to restore the French Warehouse archaeological site); filling Camille Cut to recreate a continuous Ship Island; and restoring natural regional sediment transport processes by placing sand in the littoral zone just east of Petit Bois Island. Prevailing sediment transport processes will provide natural renourishment of the westward islands in the barrier system (U.S. Army Corps of Engineers, 2009b). One difficulty in developing the final recommendations is that few data are available to incorporate into restoration plans related to bathymetry, sediment type, and biota. For example, the most recent bathymetry available dates to when East and West Ship Islands were a single continuous island (1917). As a result, the MsCIP program has encouraged post-hurricane bathymetric data collection for future reference. Furthermore, managing a complex environment such as this barrier island system for habitat conservation and best resource usage requires significant knowledge about those habitats and resources. To effectively address these issues, a complete and comprehensive understanding of the type, geographic extent, and condition of marine resources included within the GUIS is required. However, the data related to the GUIS marine resources are limited either spatially or temporally. Specifically, there is limited knowledge and information about the distribution of benthic habitats and the characteristics of the offshore region of the GUIS, even though these are the habitats that will be most affected by habitat restoration. The goal of this project is to develop a comprehensive map of the benthic marine habitats within the GUIS to give park managers the ability to develop strategies for coastal and ocean-resource management and to aid decisionmakers in evaluating conservation priorities.

Mississippi↗

USGS2013

Statewide summary for Mississippi

The Mississippi coastline is 113 linear kilometers (70 miles) long and its estuaries cover approximately 594 km (369 mi; Figure 1) (Handley and others, 2007). It has a man-made sand beach 43.5 km (27 mi) long and 595.5 km (370 mi) of shoreline (Klein and others, b., 1998). The Mississippi Sound extends across the coastal waters of the State and encompasses 175,412 ha (433,443 acres). It is bordered by the Mississippi coast; Mobile Bay, Ala.; the Gulf Islands National Seashore barrier islands; and Lake Borgne, La. The watersheds and drainages feeding into Mississippi Sound, excluding tidal exchange from the Gulf of Mexico, include Lake Borgne, Pearl River, Jourdan River, Wolf River, Biloxi River, Tchoutacabouffa River, Pascagoula River, and Mobile Bay. The Pascagoula River is one of the last undammed rivers in the continental U.S. and the only undammed river flowing into the Gulf of Mexico. Freshwater inflow into Mississippi Sound, excluding that from Mobile Bay, averages 882.4 m 3 per second (30,806 ft 3 per second). The Mississippi coastal zone contains approximately one-third of the State’s 120 ecological communities (Klein and others, a., 1998). Regional land use includes silviculture, agriculture, and urban development, including several coastal casinos. Commercial shipping, shipbuilding, phosphate rock refinement, and electric power generation companies include some of the industrial complexes found along the Mississippi coast. The three counties found along the Mississippi coast, Hancock, Harrison, and Jackson Counties, had a total population of 370,702 as of 2010, constituting 12.5 percent of the State’s population (U.S. Census Bureau, 2010). These counties cover over 160.9 km (100 mi) of coastline and are one of the fastest growing regions in the state (Klein and others, b., 1998). The casino industry, military installations, trade, and manufacturing provide most jobs in coastal Mississippi. Two major deep-water ports exist in coastal Mississippi. Recreation and tourism have a significant impact on Mississippi’s economy as well, annually attracting approximately 1.8 million visitors to the coast and generating approximately \$3.5 billion statewide, about one-third of which comes from coastal tourism. Ninety percent of the coastal tourism expenditures come from recreational boating and related industries. Marine recreational fishing generates more than \$50 million annually, with approximately 280,000 participants, more than a million recreational fishing expeditions, and over 40,000 resident saltwater sportfishing licenses sold each year. More than one-fourth of the anglers fishing in coastal Mississippi are tourists. Landings of shrimp, crabs, oysters, and finfish equal approximately 99.8 million kg (220 million lbs) of seafood annually. The entire seafood industry in coastal Mississippi, including processing of seafood caught in other Gulf States, generates approximately \$450 million per year.

Mississippi↗

USGS2013

Vegetation classification and mapping, Vicksburg National Military Park, Mississippi

Executive Summary The National Park Service (NPS) Gulf Coast Inventory and Monitoring Network, with the support of the National Park Service Vegetation Inventory completed vegetation classification and mapping for Vicksburg National Military Park (VICK), in Warren County, Mississippi, from 2004 to 2010. VICK is one of more than 250 NPS units to be covered by the Vegetation Inventory. Methods and procedures follow those of the NPS Vegetation Inventory as of August, 2012 ( http://science.nature.nps.gov/im/inventory/veg/index.cfm ). Ecologists collected floristic and environmental data from 45 vegetation field plots and classified and described 13 plant community types corresponding to US National Vegetation Classification (USNVC) associations from these data. This classification was used to map 712 hectares (1,698 acres) of Vicksburg National Military Park, in ten map classes corresponding to vegetation associations and two non-vegetated land cover classes, from a digital orthomosaic created from 1:24,000 color infrared aerial photographs and digital elevation model (DEM) data. Methods used to delineate stands varied according to vegetation type and were a combination of incorporating stand boundaries from an existing map, new “heads-up” interpretation and modeling of digital environmental spatial data. A thematic accuracy assessment collected vegetation data from 118 field observations stratified across the vegetation classes. The overall accuracy of the vegetation map was estimated to be 60.5% at the thematic level of USNVC association and 92.4% at the thematic level of USNVC group. Estimates of areas of vegetation types, as adjusted for mapping error, were calculated for all types mapped and/or observed during the thematic accuracy assessment. An important finding of this study is that the composition of the forests of VICK is substantially different from that described by earlier, more qualitative, accounts. Implications of these findings and possible applications of the data for resource monitoring and management are presented. This report summarizes the methods and general results of the Vegetation Inventory for Vicksburg National Military Park. Appendices include descriptions of vegetation types, a field key to the types, a list of plant species, and accuracy assessment contingency tables. This report is supplemented by the project data, which include: spatial database containing map polygon attributes. Geospatial products are in Universal Transverse Mercator (UTM) projection, Zone 15, using the North American Datum of 1983. all field data (plot, observation point, and accuracy assessment point) stored in a Microsoft Access database metadata for all digital products The data and reports produced by this investigation reside at: https://irma.nps.gov/App/ and/or at: http://biology.usgs.gov/npsveg/

Mississippi↗

USGS2012

Local and landscape associations between wintering dabbling ducks and wetland complexes in Mississippi

Landscape features influence distribution of waterbirds throughout their annual cycle. A conceptual model, the wetland habitat complex, may be useful in conservation of wetland habitats for dabbling ducks (Anatini). The foundation of this conceptual model is that ducks seek complexes of wetlands containing diverse resources to meet dynamic physiological needs. We included flooded croplands, wetlands and ponds, public-land waterfowl sanctuary, and diversity of habitats as key components of wetland habitat complexes and compared their relative influence at two spatial scales (i.e., local, 0.25-km radius; landscape, 4-km) on dabbling ducks wintering in western Mississippi, USA during winters 2002–2004. Distribution of mallard ( Anas platyrhynchos ) groups was positively associated with flooded cropland at local and landscape scales. Models representing flooded croplands at the landscape scale best explained occurrence of other dabbling ducks. Habitat complexity measured at both scales best explained group size of other dabbling ducks. Flooded croplands likely provided food that had decreased in availability due to conversion of wetlands to agriculture. Wetland complexes at landscape scales were more attractive to wintering ducks than single or structurally simple wetlands. Conservation of wetland complexes at large spatial scales (≥5,000 ha) on public and private lands will require coordination among multiple stakeholders.

Mississippi↗

USGS2012

A quantitative assessment of the conservation benefits of the Wetlands Reserve Program to amphibians

The Mississippi Alluvial Valley (MAV) originally consisted of nearly contiguous bottomland hardwood (BLH) forest encompassing approximately 10 million hectares. Currently, only 20–25% of the historical BLH forests remain in small patches fragmented by agricultural lands. The Wetlands Reserve Program (WRP) was established to restore and protect the functions and values of wetlands in agricultural landscapes. To assess the potential benefit of WRP restoration to amphibians, we surveyed 30 randomly selected WRP sites and 20 nearby agricultural sites in the Mississippi Delta. We made repeat visits to each site from May to August 2008 and performed both visual encounter and vocalization surveys. We analyzed the encounter history data for 11 anuran species using a Bayesian hierarchical occupancy model that estimated detection probability and probability of occurrence simultaneously for each species. Nine of the 11 species had higher probabilities of occurrence at WRP sites compared to agriculture. Derived estimates of species richness were also higher for WRP sites. Five anuran species were significantly more likely to occur in WRP than in agriculture, four of which were among the most aquatic species. It appears that the restoration of a more permanent hydrology at the WRP sites may be the primary reason for this result. Although amphibians represent only one group of wildlife species, they are useful for evaluating restoration benefits for wildlife because of their intermediate trophic position. The methods used in this study to evaluate the benefit of restoration could be used in other locations and with other groups of indicator species.

Mississippi↗

USGS2012

Backwaters in the upper reaches of reservoirs produce high densities of age-0 crappies

Reservoir backwaters are aquatic habitats in floodplains of reservoir tributaries that are permanently or periodically flooded by the reservoir. Like many reservoir arms, backwaters are commonly shallow, littoral habitats, but they differ from arms in various respects, including their support of primarily wetland plant assemblages that are tolerant to flooding. Elsewhere, the reservoir floods mainly upland plants that are less tolerant to flooding, producing a band of barren shoreline along the fluctuation zone. We investigated differences in relative abundance of age-0 crappies Pomoxis spp. in backwaters and arms of widely fluctuating flood control reservoirs, examined the effect of water level, and estimated the likelihood and timing with which these habitats are flooded annually. Higher catch rates of age-0 crappies were obtained in backwater habitats than in arm habitats. When inundated during the crappie spawning season, backwaters provided vegetated habitat at lower water levels than arms. Backwaters flooded earlier than arms and remained flooded longer to provide prolonged nursery habitat. Whereas vegetated habitat was inundated almost yearly in backwaters and arms, inundation that was timed to the onset of spawning occurred less regularly. Because of differences in water elevation, vegetated habitats were flooded in time for crappie spawning about every other year in backwaters but only every third year in arms. Recruitment of age-0 crappies was inversely correlated with high water levels during the months preceding the spawning period, perhaps because early flooding degraded the vegetation. Our results suggest that water levels may be managed during late winter and spring to regularly flood wetland vegetation communities in backwaters; however, water levels should be maintained at or below normal pool and should only irregularly flood upland vegetation in reservoir arms to promote the preservation of such vegetation. Furthermore, management efforts to enhance crappie recruitment should consider the enhancement and preservation of backwaters.

Mississippi↗

USGS2012

Trolling may intensify exploitation in crappie fisheries

In some parts of the USA, anglers targeting crappies Pomoxis spp. are transitioning from mostly stationary angling with a single pole around submerged structures to using multiple poles while drifting with the wind or under power. This shift in fishing methods could result in a change in catch efficiency, possibly increasing exploitation rates to levels that would be of concern to managers. We studied the catch statistics of anglers fishing while trolling with multiple poles (trollers) and those fishing with single poles (polers) in Mississippi reservoirs. Specifically, we tested whether (1) various catch statistics differed between trollers and polers, (2) catch rates of trollers were related to the number of poles fished, and (3) trollers could raise exploitation rates to potentially unsustainable levels. Results showed that participation in the crappie fisheries was about equally split between polers and trollers. In spring, 90% of crappie anglers were polers; in summer, 85% of crappie anglers were trollers. The size of harvested crappies was similar for the two angler groups, but the catch per hour was almost three times higher for trollers than for polers. Catch rates by trollers were directly correlated to the number of poles fished, although the relationship flattened as the number of poles increased. The average harvest rate for one troller fishing with three poles was similar to the harvest rate obtained by one poler. Simulations predicted that at the existing mix of about 50% polers and 50% trollers and with no restrictions on the number of poles used by trollers, exploitation of crappies is about 1.3 times higher than that in a polers-only fishery; under a scenario in which 100% of crappie anglers were trollers, exploitation was forecasted to increase to about 1.7 times the polers-only rate. The efficiency of trolling for crappies should be of concern to fishery managers because crappie fisheries are mostly consumptive and may increase exploitation rates to unsustainable levels.

Mississippi↗

USGS2012

Groundwater and surface-water exchange and resultingnNitrate dynamics in the Bogue Phalia Basin in northwestern Mississippi

During April 2007 through September 2008, the USGS collected hydrogeologic and water-quality data from a site on the Bogue Phalia to evaluate the role of groundwater and surface-water interaction on the transport of nitrate to the shallow sand and gravel aquifer underlying the Mississippi Alluvial Plain in northwestern Mississippi. A two-dimensional groundwater/surface-water exchange model was developed using temperature and head data and VS2DH, a variably saturated flow and energy transport model. Results from this model showed that groundwater/surface-water exchange at the site occurred regularly and recharge was laterally extensive into the alluvial aquifer. Nitrate was consistently reported in surface-water samples ( n = 52, median concentration = 39.8 μmol/L) although never detected in samples collected from in-stream piezometers or shallow monitoring wells adjacent to the stream ( n = 46). These two facts, consistent detections of nitrate in surface water and no detections of nitrate in groundwater, coupled with model results that indicate large amounts of surface water moving through an anoxic streambed, support the case for denitrification and nitrate loss through the streambed.

Mississippi↗

USGS2012

CO 2 –rock–brine interactions in Lower Tuscaloosa Formation at Cranfield CO 2 sequestration site, Mississippi, U.S.A.

A highly integrated geochemical program was conducted at the Cranfield CO 2 -enhanced oil recovery (EOR) and sequestration site, Mississippi, U.S.A.. The program included extensive field geochemical monitoring, a detailed petrographic study, and an autoclave experiment under in situ reservoir conditions. Results show that mineral reactions in the Lower Tuscaloosa reservoir were minor during CO 2 injection. Brine chemistry remained largely unchanged, which contrasts with significant changes observed in other field tests. Field fluid sampling and laboratory experiments show consistently slow reactions. Carbon isotopic composition and CO 2 content in the gas phase reveal simple two-end-member mixing between injected and original formation gas. We conclude that the reservoir rock, which is composed mainly of minerals with low reactivity (average quartz 79.4%, chlorite 11.8%, kaolinite 3.1%, illite 1.3%, concretionary calcite and dolomite 1.5%, and feldspar 0.2%), is relatively unreactive to CO 2 . The significance of low reactivity is both positive, in that the reservoir is not impacted, and negative, in that mineral trapping is insignificant.

Mississippi↗

USGS2012

A comparison of artificial incubation and natural incubation hatching success of gopher tortoise (Gopherus polyphemus) eggs in southern Mississippi

Recent studies have found that Gopher Tortoise, Gopherus polyphemus, populations in southern Mississippi exhibit low recruitment, due in part to very low hatching success of their eggs. We sought to determine if the cause(s) of this low hatching success was related to egg quality (intrinsic factors), unsuitability of the nest environment (extrinsic factors), or a combination of the two. In 2003, hatching success was monitored simultaneously for eggs from the same clutches that were incubated in the laboratory and left to incubate in nests. A subset of randomly chosen eggs from each clutch was incubated in the laboratory under physical conditions that were known to be conducive to successful hatching to estimate the proportion of eggs that were capable of hatching in a controlled setting. Hatching success in the laboratory was compared with that of eggs incubated in natural nests to estimate the proportion of eggs that failed to hatch presumably from extrinsic factors. Laboratory hatching success was 58.8%, suggesting that roughly 40% of the eggs were intrinsically incapable of hatching even when incubated under controlled conditions. Hatching success in natural nests, 16.7%, was significantly lower than hatching success in the laboratory, suggesting that approximately 42.1% of eggs were capable of hatching but failed to hatch due to some extrinsic aspect(s) of the nest environment. Thus, the low hatching success of Gopher Tortoise eggs in southern Mississippi appears to be attributable to a combination of intrinsic (egg quality) and extrinsic (nest environment) factors.

Mississippi↗

USGS2012

Provisioning of nestling Dickcissels in native warm-season grass field buffers

We used video cameras in 2008–2009 to record provisioning activities at Dickcissel (Spiza americana) nests in and around Conservation Reserve Program field buffers in north-central Mississippi, USA. We simultaneously observed foraging flight distances of parents. Provisioning rate (P = 0.412), biomass (P = 0.161), and foraging distance (P = 0.159) did not increase with nestling age. Parents delivered larger items to meet demand associated with older nestlings (P = 0.010–0.001). This suggests energetic costs of changes in prey selection were less than costs of increasing the number or distance of provisioning trips. Presence of male helpers increased provisioning rate (P < 0.001) but not biomass (P = 0.992) because males brought smaller prey items (P = 0.001–0.021). Presence of observers 30 m from the nest reduced provisioning rates (P = 0.005) and biomass delivered (P = 0.066). Lack of habitat effects for any aspect of provisioning suggests grass field buffers provided nestling food resources similar to surrounding habitats. Use of continuous video monitoring of nest activity allows well-concealed activities including provisioning and male helping to be directly observed and better quantified.

Mississippi↗