The Foraminifera of Chincoteague Bay, Assateague Island, and the Surrounding Areas: a Regional Distribution Study

2018 ◽  
Vol 48 (3) ◽  
pp. 223-240 ◽  
Author(s):  
Alisha M. Ellis ◽  
Jaimie E. Shaw ◽  
Lisa E. Osterman ◽  
Christopher G., Smith
Keyword(s):  
Salt Marshes ◽  
Census Data ◽  
Regional Distribution ◽  
Environmental Parameters ◽  
Anthropogenic Pollution ◽  
Organic Content ◽  
Mechanical Destruction ◽  
Distribution Study ◽  
Chincoteague Bay ◽  
Assateague Island

Abstract Foraminiferal census data from Chincoteague Bay, Newport Bay, the salt marshes of Assateague Island, adjacent mainland salt marshes, and the inner-shelf, were assessed to determine the current assemblages in Chincoteague Bay, and how the different environments surrounding the bay, and the gradients within the bay, influence the microfossil distribution. Determining the current background distribution and its drivers allows for future comparisons to determine paleoenvironmental conditions, impacts from natural and anthropogenic pollution, and the influence of climate change. Foraminiferal census data were compared to sedimentological characteristics and environmental parameters, exhibiting strong correlations with salinity, sediment organic content, and grain-size. Foraminiferal distributions exhibited a gradient from an assemblage dominated by Elphidium cf. E. excavatum near Chincoteague inlet to an assemblage dominated by Ammonia parkinsoniana and Ammobaculites cf. Ab. exiguus in the more restricted central and northern portions of the bay. The sites closest to the mouth of Trappe Creek in Newport Bay, along the western side of Chincoteague Bay and in the central bay, had a greater relative abundance of dead agglutinated taxa compared with the majority of sites in Chincoteague Bay. Despite the overwhelming dominance of calcareous taxa throughout the bay, dissolution may affect the preservation potential of Cribroelphidium poeyanum and Haynesina germanica in the northern and central portions of Chincoteague Bay, as indicated by seasonal pH data. Similarly, the sandy back-barrier lagoonal sites exhibited relatively low densities, potentially a result of dissolution or mechanical destruction.

scholarly journals Temporal and spatial variability of heavy metals in Marudu Bay, Malaysia

2016 ◽  
Vol 45 (3) ◽  
Author(s):  
Tan Kar Soon ◽  
Delta Jenetty Denil ◽  
Julian Ransangan
Keyword(s):  
Heavy Metals ◽  
Surface Sediment ◽  
Environmental Parameters ◽  
Organic Content ◽  
Terrestrial Organic Matter ◽  
Total N ◽  
Anthropogenic Inputs ◽  
Baseline Concentration ◽  
Temporal And Spatial Variability ◽  
Geochemical Normalization

AbstractThe current study was conducted to estimate the baseline concentration of heavy metals in the surface sediment of Marudu Bay. Environmental parameters were measured at the seafloor and samples of the surface sediment were collected at monthly intervals for the period of 12 months. The organic content, total N, total P and concentration of 16 trace metals in the surface sediment were analyzed. The baseline concentration of metals was estimated by geochemical normalization. Anthropogenic inputs of metals were then estimated by calculating the enrichment factor for each element. The result demonstrated that the C/N ratio of sediment at Marudu Bay varies from 15 to 342, which indicates the dominance of terrestrial organic matter. The baseline concentration of V, Fe, Mn, Zn, Ti, Rb and Sr were 26.74 mg kg

scholarly journals Incorporating Geographical Scale and Multiple Environmental Factors to Delineate the Breeding Distribution of Sea Turtles

Drones ◽  
2021 ◽  
Vol 5 (4) ◽  
pp. 142
Author(s):  
Liam C. Dickson ◽  
Kostas A. Katselidis ◽  
Christophe Eizaguirre ◽  
Gail Schofield
Keyword(s):  
Sea Turtles ◽  
Regional Distribution ◽  
Environmental Parameters ◽  
Environmental Data ◽  
Offshore Wind ◽  
Loggerhead Sea Turtles ◽  
Change Models ◽  
Terrestrial Environments ◽  
Aircraft System ◽  
Marine Megafauna

Temperature is often used to infer how climate influences wildlife distributions; yet, other parameters also contribute, separately and combined, with effects varying across geographical scales. Here, we used an unoccupied aircraft system to explore how environmental parameters affect the regional distribution of the terrestrial and marine breeding habitats of threatened loggerhead sea turtles (Caretta caretta). Surveys spanned four years and ~620 km coastline of western Greece, encompassing low (<10 nests/km) to high (100–500 nests/km) density nesting areas. We recorded 2395 tracks left by turtles on beaches and 1928 turtles occupying waters adjacent to these beaches. Variation in beach track and inwater turtle densities was explained by temperature, offshore prevailing wind, and physical marine and terrestrial factors combined. The highest beach-track densities (400 tracks/km) occurred on beaches with steep slopes and higher sand temperatures, sheltered from prevailing offshore winds. The highest inwater turtle densities (270 turtles/km) occurred over submerged sandbanks, with warmer sea temperatures associated with offshore wind. Most turtles (90%) occurred over nearshore submerged sandbanks within 10 km of beaches supporting the highest track densities, showing the strong linkage between optimal marine and terrestrial environments for breeding. Our findings demonstrate the utility of UASs in surveying marine megafauna and environmental data at large scales and the importance of integrating multiple factors in climate change models to predict species distributions.

Standing Crop of Salt Marshes Surrounding Chincoteague Bay, Maryland-Virginia

1973 ◽  
Vol 14 (2) ◽  
pp. 117 ◽  
Author(s):  
Carolyn W. Keefe ◽  
Walter R. Boynton
Keyword(s):  
Salt Marshes ◽  
Standing Crop ◽  
Chincoteague Bay

scholarly journals Geomorphic influences on the contribution of vegetation to soil C accumulation and accretion in <i>Spartina alterniflora</i> marshes

2017 ◽  
Author(s):  
Tracy Elsey-Quirk ◽  
Viktoria Unger
Keyword(s):  
Spartina Alterniflora ◽  
Environmental Conditions ◽  
Salt Marshes ◽  
Plant Biomass ◽  
Full Range ◽  
Environmental Parameters ◽  
Belowground Biomass ◽  
Soil C ◽  
Accretion Rates ◽  
Biomass Dynamics

Abstract. Environmental conditions have a strong influence on rates plant productivity and decomposition. In salt marshes, hydrology and salinity are important regulators of plant and soil processes, which, in turn, can influence the rate at which marsh ecosystems accumulate C and adjust to sea-level rise. For this study, we examined the influence of multivariate environmental conditions on belowground ingrowth (roots + rhizomes), decomposition and biomass in marshes dominated by Spartina alterniflora across two estuaries and a range of geomorphic settings. Secondly, we examined the influence of belowground plant biomass to soil C density, and C (labile and refractory) accumulation and accretion rates. Study locations occupied a full range of tidal elevations from below mean low water to above mean high water. Salinities ranged from 7–40, and soil properties also varied across marshes. While many of the environmental parameters were correlated across marshes, belowground ingrowth of S. alterniflora was negatively influenced by mean low water height, such that root growth increased with more drainage. Belowground decay rate increased with increasing salinity, but ultimately the percent of mass remaining was similar across marshes, averaging 59 ± 1 %. Above- and belowground biomass dynamics were estuary-dependent. In the coastal lagoon estuary, less flooding and a higher sedimentation rate favored above-and belowground biomass, which, in turn, increased soil C accumulation and accretion rates. Biomass dynamics in the coastal plain estuary, for the most part, were unrelated to environmental predictor variables, and had little influence on the accumulation of soil C or accretion rate. These findings indicate that mineral sedimentation is of utmost importance for promoting belowground biomass and soil C accumulation in sediment-limited systems while in minerogenic systems, belowground biomass may not scale with C accumulation and accretion, which may be influenced more by smaller submillimetre-sized C particles.

scholarly journals Identification of early Llandovery (Silurian) anoxic palaeo-depressions at the western margin of the Murzuq Basin (southwest Libya), based on gamma-ray spectrometry in surface exposures

GeoArabia ◽  
2006 ◽  
Vol 11 (3) ◽  
pp. 101-118 ◽  
Author(s):  
Nuri Fello ◽  
Sebastian Lüning ◽  
Petr Štorch ◽  
Jonathan Redfern
Keyword(s):  
Black Shale ◽  
Gamma Ray ◽  
Regional Distribution ◽  
Uranium Content ◽  
Organic Content ◽  
Black Shales ◽  
Gamma Ray Spectrometry ◽  
Hydrocarbon Source Rock ◽  
Western Margin ◽  
Anoxic Event

ABSTRACT Following the melting of the Gondwanan icecap and the resulting postglacial sea-level rise, organic-rich shales were deposited in shelfal palaeo-depressions across North Africa and Arabia during the latest Ordovician to earliest Silurian. The unit is absent on palaeohighs that were flooded only later when the anoxic event had already ended. The regional distribution of the Silurian black shale is now well-known for the subsurface of the central parts of the Murzuq Basin, in Libya, where many exploration wells have been drilled and where the shale represents the main hydrocarbon source rock. On well logs, the Silurian black shale is easily recognisable due to increased uranium concentrations and, therefore, elevated gamma-ray values. The uranium in the shales “precipitated” under oxygen-reduced conditions and generally a linear relationship between uranium and organic content is developed. The distribution of the Silurian organic-rich shales in the outcrop belts surrounding the Murzuq Basin has been long unknown because Saharan surface weathering has commonly destroyed the organic matter and black colour of the shales, making it complicated to identify the previously organic-rich unit in the field. In an attempt to distinguish (previously) organic-rich from organically lean shales at outcrop, seven sections that straddle the Ordovician-Silurian boundary were measured by portable gamma-ray spectrometer along the outcrops of the western margin of the Murzuq Basin. It was found that the uranium content of the shales remained largely unaltered by the weathering processes and could therefore be used as a valid proxy parameter to distinguish between pre-weathering organically rich and lean shales. It is now possible to identify and map-out the thickness and approximate organic richness of the black shale using measurement of uranium radiation. Five of the newly measured sections are characterised by uranium-enriched intervals, representing areas of earliest Silurian palaeo-depressions. Major uranium peaks are absent in the spectral gamma-ray curves of two other sections, which are interpreted to mark earliest Silurian palaeo-highs. The new data on the distribution of Silurian black shales from the outcrop belt was integrated with subsurface data from the Murzuq Basin. The resulting map of the distribution of black shales may help with predictions of the occurrence of this unit in less well-explored areas of the basin. Graptolite biostratigraphic data suggests that the anoxic event centred on the middle Rhuddanian, with more oxygenated conditions and onset of deposition of organically leaner shales having commenced sometime during the late Rhuddanian. The presence of anoxic palaeo-depressions during the earliest Silurian within the Ghat outcrop belt indicates that the Tihemboka High at the western margin of the Murzuq Basin could not have been a positive structure during this time.

Will hurricane sedimentation aid southeastern US saltmarsh resiliency in the face of climate change and sea-level rise?

2021 ◽  
Author(s):  
Alice Staro ◽  
Duncan FitzGerald ◽  
Zoe Hughes ◽  
Christopher Hein ◽  
Ioannis Georgiou ◽  
...  
Keyword(s):  
Climate Change ◽  
South Carolina ◽  
Sea Level Rise ◽  
Sea Level ◽  
Storm Surge ◽  
Salt Marshes ◽  
Marsh Surface ◽  
Organic Content ◽  
Southeastern Us ◽  
Hurricane Irma

&lt;p&gt;Coastal saltmarshes are an important and highly diverse ecosystem, shielding the mainland from erosion and flooding. Along the US East Coast these valuable wetlands are endangered due to climate change, sea-level rise, and reduced fluvial sediment fluxes. Although hurricanes are commonly an erosional agent, they may be responsible for delivering significant volumes of sediment to the marsh surface, which could aid resiliency by increasing vertical accretion. This study analyzes marsh sediment cores collected during December 2017 within the Georgia Bight, targeting deposits associated with Hurricane Irma, which caused significant wave energy and storm surge along the coast from Florida to South Carolina in September 2017.&lt;/p&gt;&lt;p&gt;We have focused our initial research on samples from Sapelo Island (Georgia), where Hurricane Irma produced maximum wind velocities of 17.5 m/s and a 1.3 m storm surge, inundating the marsh for 14.8 hrs. We find that Irma-related layers are between 2 and 7 cm thick and well-oxidized. These deposits typically consist of laminated mud with low organic content (LOI: 10-25%) and low bulk density (0.3-0.8 g/cm&lt;sup&gt;3&lt;/sup&gt;). On average, Irma event sediment thickness is 4 times the historical average annual accretion, which in Georgia salt marshes is 1.55 mm.&lt;/p&gt;&lt;p&gt;A direct comparison of Irma-affiliated marsh accretion and historical rates is complicated due to differences in consolidation, rooting and vegetation, and the sedimentation history of the marsh. Nonetheless, the storm layer represents a significant addition of sediment to the marsh surface. Thus, future increases in event sedimentation, associated with increased frequency or severity of storms, could help compensate for sea-level rise and lessen the likelihood or extent of marsh loss due to submergence.&lt;/p&gt;

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