scholarly journals Sex-associated variations in coral skeletal oxygen and carbon isotopic composition of <i>Porites panamensis</i> in the southern Gulf of California

2015 ◽  
Vol 12 (22) ◽  
pp. 18795-18827 ◽  
Author(s):  
R. A. Cabral-Tena ◽  
A. Sánchez ◽  
H. Reyes-Bonilla ◽  
A. H. Ruvalcaba-Díaz ◽  
E. F. Balart
Keyword(s):  
Gulf Of California ◽  
Growth Parameters ◽  
Isotope Composition ◽  
Seasonal Pattern ◽  
Carbon Isotopic Composition ◽  
Coral Growth ◽  
Metabolic Effects ◽  
Published Data ◽  
Isotope Record ◽  
Δ18o And Δ13c

Abstract. Coral δ18O variations are used as a proxy for changes in near sea surface temperature and seawater isotope composition. Skeletal δ13C of coral is frequently used as a proxy for solar radiation because most of its variability is controlled by an interrelationship between three processes: photosynthesis, respiration, and feeding. Coral growth rate is known to influence the δ18O and δ13C isotope record to a lesser extent. Recent published data show differences in growth parameters between female and male coral; thus, skeletal δ18O and δ13C are hypothesized to be different in each sex. To assess this difference, this study describes changes in the skeletal δ18O and δ13C record of four female and six male Porites panamensis coral collected in Bahía de La Paz, whose growth bands spanned 12 years. The isotopic data were compared to SST, precipitation, PAR, chlorophyll a, and skeletal growth parameters. Porites panamensis is a known gonochoric brooder whose growth parameters are different in females and males. Splitting the data by sexes explained 81 and 93 % of the differences of δ18O, and of δ13C, respectively, in the isotope record between colonies. Both isotope records were different between sexes. δ18O was higher in female colonies than in male colonies, with a 0.31 ‰ difference; δ13C was lower in female colonies, with a 0.28 ‰ difference. A difference in the skeletal δ18O implies an error in SST estimates of &amp;approx; 1.0 °C to &amp;approx; 2.6 °C. The δ18O records showed a seasonal pattern that corresponded to SST, with low correlation coefficients (−0.45, −0.32), and gentle slopes (0.09 ‰ °C−1, 0.10 ‰ °C−1) of the δ18O–SST relation. Seasonal variation in coral δ18O represents only 52.37 and 35.66 % of the SST cycle; 29.72 and 38.53 % can be attributed to δ18O variability in seawater. δ13C data did not correlate with any of the environmental variables; therefore, variations in skeletal δ13C appear to be driven mainly by metabolic effects. Our results support the hypothesis of a sex-associated difference in skeletal δ18O and δ13C signal, and suggest that environmental conditions and coral growth parameters affect skeletal isotopic signal differently in each sex.

scholarly journals Sex-associated variations in coral skeletal oxygen and carbon isotopic composition of <i>Porites panamensis</i> in the southern Gulf of California

2016 ◽  
Vol 13 (9) ◽  
pp. 2675-2687 ◽  
Author(s):  
Rafael A. Cabral-Tena ◽  
Alberto Sánchez ◽  
Héctor Reyes-Bonilla ◽  
Angel H. Ruvalcaba-Díaz ◽  
Eduardo F. Balart
Keyword(s):  
Environmental Variables ◽  
Gulf Of California ◽  
Growth Parameters ◽  
Isotope Composition ◽  
Carbon Isotopic Composition ◽  
Coral Growth ◽  
Metabolic Effects ◽  
Published Data ◽  
Isotope Record ◽  
Δ18o And Δ13c

Abstract. Coral δ18O variations are used as a proxy for changes in sea surface temperature (SST) and seawater isotope composition. Skeletal δ13C of coral is frequently used as a proxy for solar radiation because most of its variability is controlled by an interrelationship between three processes: photosynthesis, respiration, and feeding. Coral growth rate is known to influence the δ18O and δ13C isotope record to a lesser extent than environmental variables. Recent published data show differences in growth parameters between female and male coral in the gonochoric brooding coral Porites panamensis; thus, skeletal δ18O and δ13C are hypothesized to be different in each sex. To test this, this study describes changes in the skeletal δ18O and δ13C record of four female and six male Porites panamensis coral collected in Bahía de La Paz, Mexico, whose growth bands spanned 12 years. The isotopic data were compared to SST, precipitation, photosynthetically active radiation (PAR), chlorophyll a, and skeletal growth parameters. Porites panamensis is a known gonochoric brooder whose growth parameters are different in females and males. Splitting the data by sexes explained 81 and 93 % of the differences of δ18O, and of δ13C, respectively, in the isotope record between colonies. Both isotope records were different between sexes. δ18O was higher in female colonies than in male colonies, with a 0.31 ‰ difference; δ13C was lower in female colonies, with a 0.28 ‰ difference. A difference in the skeletal δ18O could introduce an error in SST estimates of  ≈  1.0 to  ≈  2.6 °C. The δ18O records showed a seasonal pattern that corresponded to SST, with low correlation coefficients (−0.45, −0.32), and gentle slopes (0.09, 0.10 ‰ °C−1) of the δ18O–SST relation. Seasonal variation in coral δ18O represents only 52.37 and 35.66 % of the SST cycle; 29.72 and 38.53 % can be attributed to δ18O variability in seawater. δ13C data did not correlate with any of the environmental variables; therefore, variations in skeletal δ13C appear to be driven mainly by metabolic effects. Our results support the hypothesis of a sex-associated difference in skeletal δ18O and δ13C signal, and suggest that environmental conditions and coral growth parameters affect skeletal isotopic signals differently in each sex. Although these findings relate to one gonochoric brooding species, they may have some implications for the more commonly used gonochoric spawning species such as Porites lutea and Porites lobata.

Climate and land-use effects on hydrological and vegetation signals during the last three millennia: Evidence from sedimentary leaf waxes in southwestern Morocco

The Holocene ◽  
2021 ◽  
pp. 095968362098805
Author(s):  
Asmae Baqloul ◽  
Enno Schefuß ◽  
Martin Kölling ◽  
Lydie Dupont ◽  
Jeroen Groeneveld ◽  
...  
Keyword(s):  
Land Use ◽  
Carbon Isotope ◽  
Vegetation History ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Economic Stress ◽  
Published Data ◽  
Leaf Waxes ◽  
Argan Tree ◽  
Precipitation Changes

The southwest of Morocco is considered to be an area of refuge within the Mediterranean region, hosting the endemic tropical Argan tree. This region is presently subject to severe droughts, desertification and land degradation, and likely facing increased climate variability and socio-economic stress in the future. Here, we use the stable hydrogen and carbon isotope composition (δD and δ13C) of plant-waxes in a high-resolution marine sediment core (GeoB8601-3) collected off Cape Ghir in southwestern Morocco, in combination with published data on pollen and XRF element ratios from the same archive. We aim to reconstruct the hydroclimate and vegetation history during the last 3000 years. Stable carbon isotope compositions of leaf waxes (δ13Cwax) show that natural vegetation in southwestern Morocco consists of C3 plants. Minor variations in δ13Cwax were positively correlated to changes in stable hydrogen isotope compositions of leaf waxes (δDwax) before 700 CE. Changes in rainfall amounts and water use efficiency indicate a clear vegetation response to precipitation changes and thus to climate forcing. After 700 CE, δDwax and δ13Cwax became de-coupled suggesting that the plant wax discharge and their isotope signals were no longer solely controlled by climate; the waxes likely mainly originate from the lowlands and carry an enriched (dry) δD signal but a depleted 13C signature. The depletion of δ13Cwax correlates with the increase of Argan pollen concentration in the record. The period between ~700 and 900 CE coincides with the Arabization of Morocco which had an impact on the demographic composition of the country leading to new agricultural habits and, as a result, on the land-use triggering a higher erosion of lowland material by the Souss River.

scholarly journals INDICADORES ECOLÓGICOS DE LA ESTRUCTURA DE LA COMUNIDAD FITOPLANCTÓNICA EN BAHÍA CONCEPCIÓN, GOLFO DE CALIFORNIA, MÉXICO

2010 ◽  
Vol 25 (2) ◽  
pp. 95
Author(s):  
G. Verdugo-Díaz ◽  
A. Martínez-López ◽  
I. Gárate-Lizárraga
Keyword(s):  
Water Column ◽  
Gulf Of California ◽  
Phytoplankton Community ◽  
Seasonal Pattern ◽  
Warm Season ◽  
Phytoplankton Abundance ◽  
Important Group ◽  
Clear Seasonal Pattern ◽  
High Species Richness ◽  
Phytoplankton Size

Se presentan los cambios en la distribución espacial de la comunidad fitoplanctónica en Bahía Concepción, B.C.S. de 1991 a 1993. Se estimó la abundancia total, la variación espacio-temporal por fracciones de tamaño (nano y microfitoplancton) y se describe su estructura. Se determinaron 235 taxa, en donde las diatomeas fueron el grupo con mayor riqueza de especies (131). Los géneros más importantes fueron Chaetoceros, Rhizosolenia y Nitzschia. El segundo grupo en importancia fue el de los dinoflagelados (92 especies), representados principalmente por Protoperidinium, Ceratium y Prorocentrum; el tercer grupo fueron los silicoflagelados (9 especies), principalmente del genero Dictyocha. Las diatomeas dominaron en la temporada fría cuando la columna de agua se mantiene homogénea, en tanto que los dinoflagelados prosperaron durante la temporada cálida cuando la columna de agua estuvo estratificada. De este último grupo, 10 especies son tóxicas o potencialmente tóxicas. La abundancia fitoplanctónica total no mostró un comportamiento estacional definido, sin embargo, las variaciones interanuales mostraron un decremento de aproximadamente 25% durante 1992 y 1993, asociado con anomalías positivas de temperatura. A pesar de que las abundancias totales disminuyeron, la contribución porcentual de la fracción nanofitoplanctónica se mantuvo. Ecological indicators of the phytoplankton community structure in Bahía Concepción, Gulf of California, Mexico Seasonal changes in the spatial distribution of the phytoplankton community were determined in Bahía Concepción, B.C.S., from 1991 to 1993. The total abundance and the seasonal variations of phytoplankton size fractions (nanno and microphytoplankton) as well as its structure were determined. A total of 235 taxa were identified. Diatoms were the best represented group due to their high species richness (131). The most important genera were Chaetoceros, Rhizosolenia and Nitzschia. The second important group were dinoflagellates (92 species), represented mainly by Protoperidinium, Ceratium and Prorocentrum. The third numerically important group were the silicoflagellates (9 species). The most representative genus of this group was Dictyocha. A major presence of the diatoms was observed during the cold months with a homogeneous water-column. Major presence of dinoflagellates was recorded during the warm season when the water-column appeared stratified. Ten species of dinoflagellates were considered as toxic or potentially toxic. Total phytoplankton abundance did not show a clear seasonal pattern; nevertheless, the interannual variations exhibited an important decline of about 25 % during 1992 and 1993. These changes were related to positive anomalies of temperature. Altough phytoplankton abundance diminished, the percentage contribution of nannophytoplankton was stable.

Anions and Cations in Ice Cores from Dolleman Island and the Palmer Land Plateau, Antarctic Peninsula

1988 ◽  
Vol 10 ◽  
pp. 121-125 ◽  
Author(s):  
Robert Mulvaney ◽  
David A. Peel
Keyword(s):  
Antarctic Peninsula ◽  
Isotope Composition ◽  
Seasonal Pattern ◽  
Austral Summer ◽  
Ice Cores ◽  
Late Summer ◽  
Ionic Species ◽  
Weddell Sea ◽  
Seasonal Maximum ◽  
A Site

High-resolution anion profiles of Cl-, NO3- and SO4 2− are presented for two cores from the Antarctic Peninsula. A 47.2 m core from a site on the Palmer Land plateau (74°01’S, 70°38’W), spans the period 1942–80, and a 10.5 m core from Dolleman Island (70°35.2’S, 60°55.5’W), on the east coast of the peninsula, spans the period 1973–85. The seasonal pattern of deposition of these species has been determined by reference to the oxygen-isotope composition. Averaged over 38 years, the annual cycle of SO4 2− at Gomez shows a seasonal maximum during the austral summer, and minimum during the winter, whereas the Cl- cycle is more complex and may show the influence of equinoctial storms. The Dolleman core is significantly influenced by the proximity of the Weddell Sea, with a mean Cl- concentration five times greater than in the core from the plateau, and it shows a clear seasonal maximum in late-summer snowfall. There is no significant long-term trend in the 38 years’ data from the plateau site, suggesting that global pollution does not contribute significantly to the anion budget. Both anions and the cations Na+, K+ and H+ have been measured for more than a complete year of snowfall and the balance of ionic species is excellent.

scholarly journals Stable isotopic signatures in modern wood bison (Bison bison athabascae) hairs as telltale biomarkers of nutritional stress

2020 ◽  
Vol 98 (8) ◽  
pp. 505-514 ◽  
Author(s):  
Juliette Funck ◽  
Cade Kellam ◽  
C. Tom Seaton ◽  
Matthew J. Wooller
Keyword(s):  
Isotope Composition ◽  
Seasonal Pattern ◽  
Nitrogen Isotope ◽  
Nutritional Stress ◽  
Bison Bison ◽  
Long Distance ◽  
Isotopic Signatures ◽  
Wood Bison ◽  
And Behavior ◽  
Long Distance Movement

Assessing the challenges faced by wildlife populations is key to providing effective management but is problematic when dealing with populations in remote locations. Analyses of the stable carbon and nitrogen isotope composition (expressed as δ13C and δ15N values) of sequentially grown tissues, such as hairs, can be used to track changes in the eco-physiology of organisms. We generated δ13C and δ15N values from sequentially sampled (n = 465) hairs taken from wood bison (Bison bison athabascae Rhoads, 1898) (n = 27). Samples were taken from individuals prior to and after their release from captivity into the lower Innoko–Yukon river area of Alaska in 2015. Twenty months after release, individuals had a distinct seasonal pattern in δ13C values. Hairs from individuals that experienced food scarcity or long-distance movement were sampled as case studies. Nutritional stress in these cases lead to a rise in δ15N values and a decrease in δ13C values. Applications of δ13C and δ15N analyses of bison tail hairs could provide wildlife managers a valuable and minimally invasive tool to better understand bison seasonal metabolic status and determine the historical health and behavior of living and dead individuals.

Oxygen–carbon isotope composition of Middle Jurassic–Cretaceous molluscs from the Saratov–Samara Volga region and main climate trends in the Russian Platform–Caucasus

2019 ◽  
Vol 498 (1) ◽  
pp. 101-127 ◽  
Author(s):  
Yuri D. Zakharov ◽  
Vladimir B. Seltser ◽  
Mikheil V. Kakabadze ◽  
Olga P. Smyshlyaeva ◽  
Peter P. Safronov
Keyword(s):  
Carbon Isotope ◽  
Middle Jurassic ◽  
Isotope Composition ◽  
Russian Platform ◽  
Volga Region ◽  
Published Data ◽  
Climate Trends ◽  
Late Mesozoic ◽  
Oxygen And Carbon Isotope ◽  
Epipelagic Zone

AbstractOxygen and carbon isotope data from well-preserved mollusc shells and belemnite rostra are presented from the Jurassic (Bathonian, Callovian and Tithonian) and Cretaceous (Aptian, Turonian, Campanian and Maastrichtian) of the Saratov–Samara Volga region, Russia. New data provide information on the resulting trends in palaeoclimate and in palaeoceanography and palaeoecology in the late Mesozoic. Palaeotemperatures calculated from Jurassic–Cretaceous benthic (bivalves and gastropods) and semi-pelagic (ammonites) molluscs are markedly higher than those calculated from pelagic belemnites using oxygen isotopes. This is probably due to various mollusc groups of the Saratov–Samara area inhabiting different depths in the marine basins (e.g. epipelagic v. mesopelagic). Our isotope records, combined with a review of previously published data from shallow-water fossils from the Saratov–Samara area and adjacent regions permits us to infer temperature trends for the epipelagic zone from the Middle Jurassic to Cretaceous in the Russian Platform–Caucasus area. The Jurassic–Cretaceous belemnites from the Russian Platform and the Caucasus have a lower δ13C signature than the contemporaneous brachiopods, bivalves and ammonites.

scholarly journals Lower Permian brachiopods from Oman: their potential as climatic proxies

2007 ◽  
Vol 98 (3-4) ◽  
pp. 327-344 ◽  
Author(s):  
L. Angiolini ◽  
D. P. F. Darbyshire ◽  
M. H. Stephenson ◽  
M. J. Leng ◽  
T. S. Brewer ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Isotopic Analysis ◽  
Lower Permian ◽  
Published Data ◽  
Sr Isotope ◽  
Marine Sedimentation ◽  
Ice Accumulation ◽  
Secondary Layer ◽  
Data Points ◽  
Few Data

ABSTRACTThe Lower Permian of the Haushi basin, Interior Oman (Al Khlata Formation to Saiwan Formation/lower Gharif member) records climate change from glaciation, through marine sedimentation in the Haushi sea, to subtropical desert. To investigate the palaeoclimatic evolution of the Haushi Sea we used O, C, and Sr isotopes from 31 brachiopod shells of eight species collected bed by bed within the type-section of the Saiwan Formation. We assessed diagenesis by scanning electron microscopy of ultrastructure, cathodoluminescence, and geochemistry, and rejected fifteen shells not meeting specific preservation criteria. Spiriferids and spiriferinids show better preservation of the fibrous secondary layer than do orthotetids and productids and are therefore more suitable for isotopic analysis. δ18O of −3·7 to −3·1℅ from brachiopods at the base of the Saiwan Formation are probably related to glacial meltwater. Above this, an increase in δ18O may indicate ice accumulation elsewhere in Gondwana or more probably that the Haushi sea was an evaporating embayment of the Neotethys Ocean. δ13C varies little and is within the range of published data: its trend towards heavier values is consistent with increasing aridity and oligotrophy. Saiwan Sr isotope signatures are less radiogenic than those of the Sakmarian LOWESS seawater curve, which is based on extrapolation between few data points. In the scenario of evaporation in a restricted Haushi basin, the variation in Sr isotope composition may reflect a fluvial component.

scholarly journals Use of sulphur and carbon stable-isotope composition of fish scales and muscles to identify the origin of fish

Mineralogia ◽  
2011 ◽  
Vol 42 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Andrzej Trembaczowski
Keyword(s):  
Stable Isotope ◽  
Isotope Composition ◽  
Fish Scales ◽  
Carbon Stable Isotope ◽  
Stable Isotope Composition ◽  
Isotope Record

Use of sulphur and carbon stable-isotope composition of fish scales and muscles to identify the origin of fishδ34S and δ13C analyses were used to determine the origin of trout specimens. The isotope record of their scales and muscles are compared with a database previously obtained from wild- and reared fish coming from Polish rivers and pond farms. The comparison made it possible to find out whether the trout were wild or reared.

Bi-Linear Fatigue and Fracture Approach for Safety Analysis of an Offshore Structure

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Rizwan A. Khan ◽  
Suhail Ahmad
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Fracture Mechanics ◽  
Crack Growth ◽  
Growth Parameters ◽  
Limit State ◽  
Steel Structures ◽  
Published Data ◽  
Offshore Structure ◽  
Structure Degradation

The design of welded structures for the fatigue limit state is normally carried out by means of either linear or bilinear S-N curves, which have been found adequate to predict crack initiation only. To properly assess the effects of the design, fabrication, inspection, and repair strategy for structure degradation due to crack growth, fracture mechanics (FM) models need to be applied. In this paper, alternative S-N and FM formulations of fatigue are investigated. The probabilistic fracture mechanics approach predicts the fatigue life of welded steel structures in the presence of cracks under random spectrum loading. It is based on a recently proposed bi-linear relationship to model fatigue crack growth. Uncertainty modeling, especially on fatigue crack growth parameters, is undertaken with the aid of recently published data in support of the bilinear crack growth relationship. Results pertaining to the fatigue reliability and fatigue crack size evolution are presented using the Monte Carlo simulation technique and the emphasis is placed on a comparison between the linear and bilinear crack growth models. Variations in the system configuration, service life, and coefficients of crack growth laws have been studied on the parametric basis

Sign in / Sign up

Export Citation Format

Share Document