Benthic foraminifers from the continental shelf and slope of the Gulf of Mexico: an indicator of shelf hypoxia

Osterman, Lisa E.

doi:10.1016/s0272-7714(02)00352-9

Cited by 66 publications

(49 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…See Appendix 2 for more information on all identified species and on the groups of rare species. In addition, the number of planktonic foraminifers, ostracods, the Ammonia Elphidium (AE) Index (Sen Gupta et al, 1996), and the PEB Index (Osterman, 2003) are also reported in Table 2. powdered sample were leached repeatedly with hot 6 M HC, and the combined leachates were processed for Pu after the addition of a 242 Pu yield tracer.…”

Section: Methods and Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Biological, Physical, And Chemical Data From Gulf of Mexico Core PE0305-GC1

Osterman¹,

Swarzenski²,

Hollander³

2010

Open-File Report

View full text Add to dashboard Cite

Section: Methods and Resultsmentioning

confidence: 99%

“…Benthic foraminifers provide a proxy to track the development of hypoxia prior to 1985 (Blackwelder et al, 1996;Sen Gupta et al, 1996). Previous work (Osterman, 2003) determined that the relative occurrence of three low-oxygen-tolerant species is highest in the hypoxia zone (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Biological, Physical, And Chemical Data From Gulf of Mexico Core PE0305-GC1

Osterman¹,

Swarzenski²,

Hollander³

2010

Open-File Report

View full text Add to dashboard Cite

“…Our previous work established the use of the relative abundance of three low-oxygen-tolerant benthic foraminifers (Pseudononion atlanticum, Epistominella vitrea, and Buliminella morgani) as a proxy for the present hypoxic conditions on the Louisiana shelf (Osterman, 2003). This proxy, named the PEB index, can be used in sediment cores to document low-oxygen conditions.…”

Section: An Evaluation Of An Enclosed Methods For the Determination Ofmentioning

confidence: 99%

USGS science in Florida: proceedings of Florida Integrated Science Center meeting, Orlando, Florida, May 3-5, 2005

2005

Open-File Report

View full text Add to dashboard Cite

Human health and ecological concerns have arisen regarding Florida's spring waters as a steady increase in nitrate concentrations has been observed during the past 30 years. Springs discharge nearly 8 billion gallons per day and provide base flow for many rivers in Florida that flow toward coastal areas. Increased nitrogen loads in spring runs and streams have led to the formation of nuisance algal mats and exotic species of rooted aquatic plants. In response to these concerns by the State of Florida, several research studies have been using naturally-occurring isotopic and other chemical tracers to determine sources of nitrate contamination and age of ground water discharging from springs. Since 1997, more than 60 water samples have been collected from 44 springs and analyzed for isotopes ( 15 N, 3 H/ 3 He, 18 O, 2 H, 13 C) and other chemical indicators (chlorofluorocarbons (CFCs), major ions, dissolved gases, and SF 6 ). Delta 15 N values of nitrate ranged from 2.6 to 12.9 per mil (median = 5.8 per mil) and indicated that nitrate in most spring waters originated from synthetic fertilizers. Mean transit times of ground water from the Upper Floridan aquifer that discharges from these springs ranged from 5 to 39 years, based on measured concentrations of CFCs, 3 H/ 3 He, and SF 6 and various flow system models. Concentrations of these multiple transient tracers are consistent with a two-component hydrologic model with mixtures of varying proportions of young water (<8 years) from the shallow part of the aquifer and older water (20-50 years) from the deeper part of the flow system. Given residence times of 20 to 40 years for ground water discharging from most springs, it likely will take decades for nitrate concentrations to decrease to near background levels, even with immediate reductions in nitrogen inputs at the land surface. The landscape, hydrology, and ecology of Lake Wales Ridge, central Florida, are unique in many respects. The Ridge is the highest and most prominent topographic feature in peninsular Florida and contains one of the largest collections of rare and endangered species in the United States (Dobson and others, 1997), one of the highest concentrations of endemic species in North America (Martin, 1998), and more than 200 lakes, most of which are seepage lakes with significant ground-water inflow. Lake Wales Ridge (subsequently referred to as 'the Ridge') is also one of the most intensely cultivated citrus regions in the world, with citrus groves covering about 25 percent (170 square miles) of the land area. Geologically, the Ridge is underlain by highly permeable marine sands forming relict Miocene-Holocene paleoislands which support some of the oldest ecologic communities in Florida. Ground water and surface water are closely linked in this region where ground-water inflow contributes more than 80 percent of the net water input to some lakes (Sacks and others, 1998). Ground water is the primary drinking-water supply in this region. The unconfined surficial aquifer supplies drinking water for s...

show abstract

“…Mackensen et al [1995] related E. vitrea to coarse grain sizes and low carbonate contents of the sediment from the South Atlantic and Hayward et al [2006] to the presence of terrigenous mud in shelf areas from New Zealand. It has been suggested that E. vitrea is tolerant to high accumulation rate settings [Blackwelder et al, 1996] and exhibits some tolerance to anoxia [Blackwelder et al, 1996;Gustafsson and Nordberg, 2000;Osterman, 2003;Platon et al, 2005]. Deposition of phytodetritus does not trigger increased reproduction of this species [Gustafsson and Nordberg, 2001;Gooday and Hughes, 2002] but rather an upward migration to shallower depths in the sediment [Ernst et al, 2005].…”

Section: Pa4218mentioning

confidence: 99%

Paleoceanography of the southern Agulhas Plateau during the last 150 ka: Inferences from benthic foraminiferal assemblages and multispecies epifaunal carbon isotopes

et al. 2007

View full text Add to dashboard Cite

[1] Benthic foraminiferal assemblages and the carbon isotope composition of the epifaunal benthic foraminifera Epistominella exigua and Fontbotia wuellerstorfi have been investigated along core MD02-2589 located at the southern Agulhas Plateau (41°26.03 0 S, 25°15.30 0 E, 2660 m water depth). This study aims to evaluate changes in the benthic paleoenvironment and its influence on benthic d 13 C with a notable focus on E. exigua, a species associated with phytodetritus deposits and poorly studied in isotope paleoceanographic reconstructions. The benthic foraminiferal assemblages (>63 mm) show large fluctuations in species composition suggesting significant changes in the pattern of ocean surface productivity conceivably related to migrations of the Subtropical Convergence (STC) and Subantarctic Front (SAF). Low to moderate seasonality and relatively higher food supply to the seafloor are indicated during glacial marine isotope stages (MIS) 6, 4, and 2 and during MIS 3, probably associated with the northward migration of the SAF and confluence with the more stationary STC above the southern flank of the Agulhas Plateau. The lowest organic carbon supply to the seafloor is indicated from late MIS 5b to MIS 4 as a consequence of increased influence of the Agulhas Front (AF) and/or weakening of the influence of the STC over the region. Episodic delivery of fresh organic matter, similar to modern conditions at the core location, is indicated during MIS 5c-MIS 5e and at Termination I. Comparison of this paleoenvironmental information with the paired d 13 C records of E. exigua and F. wuellerstorfi suggests that organic carbon offsets d 13 C of E. exigua from ambient bottom water d 13 C DIC , while its d 13 C amplitude, on glacial-interglacial timescales, does not seem affected by changes of organic carbon supply to the seafloor. This suggests that this species calcifies preferentially during the short time span of the year when productivity peaks and phytodetritus is delivered to the seafloor. Therefore E. exigua, while offset from d 13 C DIC , potentially more faithfully records the amplitude of ambient bottom water d 13 C DIC changes than F. wuellerstorfi, notably in settings such as the Southern Ocean that experienced substantial changes through time in the organic carbon supply to the seafloor.Citation: Diz, P., I. R. Hall, R. Zahn, and E. G. Molyneux (2007), Paleoceanography of the southern Agulhas Plateau during the last 150 ka: Inferences from benthic foraminiferal assemblages and multispecies epifaunal carbon isotopes, Paleoceanography, 22, PA4218,

show abstract

Benthic foraminifers from the continental shelf and slope of the Gulf of Mexico: an indicator of shelf hypoxia

Cited by 66 publications

References 22 publications

Biological, Physical, And Chemical Data From Gulf of Mexico Core PE0305-GC1

Biological, Physical, And Chemical Data From Gulf of Mexico Core PE0305-GC1

USGS science in Florida: proceedings of Florida Integrated Science Center meeting, Orlando, Florida, May 3-5, 2005

Paleoceanography of the southern Agulhas Plateau during the last 150 ka: Inferences from benthic foraminiferal assemblages and multispecies epifaunal carbon isotopes

Contact Info

Product

Resources

About