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  • 1
    Electronic Resource
    Electronic Resource
    Oxygen bioavailability and haemoglobins in the brine shrimp Artemia franciscana (1992)
    Springer
    Marine biology 113 (1992), S. 193-200 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Bioavailability of oxygen for the saline-water invertebrate Artemia franciscana was studied, since both oxygen concentration and oxygen diffusion rate change with salinity. Total haemoglobin concentration and the relative contribution of each of three haemoglobins was measured in specimens acclimated to different salinities and oxygen concentrations. Both haemoglobin concentration and contribution were influenced by salinity and the group observed (males, females with and females without eggs). Multiple regression analysis showed that total haemoglobin concentration was better correlated with oxygen concentration than oxygen partial pressure. The relative proportions of haemoglobins 1, 2 and 3 were better correlated with oxygen partial pressure than oxygen concentration. These results are related to the oxygen carrying capacity and oxygen affinity of the haemolymph. Our results show that oxygen bioavailability in a saline-water environment depends on the response (relative contribution of Hb1, Hb2 and Hb3 or total haemoglobin concentration) that is studied. They also show that oxygen concentration and oxygen partial pressure have a different physiological impact on brine shrimp.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00347271
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    Paper (German National Licenses)
    Fulltext
  • 2
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    Kinetics of waterborne strontium uptake in the common carp,Cyprinus carpio, at different calcium levels (2000)
    SETAC
    In:  Environmental Toxicology and Chemistry, 19 (3). pp. 622-630.
    Details
    Publication Date: 2015-07-24
    Description: The uptake kinetics of strontium in the commoncarp(Cyprinus carpio) were characterized in vivo, exposing preac-climated fish to a wide range of Sr2+ (0.27 μM–10.0 mM) and Ca2+ (10 μM–10 mM) concentrations in water; 85Sr, 45Ca, and 47Ca were used as tracers in determining the uptake, and the possibility of adsorption of the tracers to the exterior of the fish were verified. The uptake rates were determined in the whole body, gills, and blood of the fish after an exposure period of 3 h and were analyzed as a function of the free-ion activity of strontium and calcium in water. With the increase of Sr2+ concentration in the exposure water, Sr2+ uptake did not increase linearly but displayed Michaelis–Menten saturation kinetics, and with the increase of Ca2+ concentration, Sr2+ uptake decreased significantly in the whole body, gills, and blood. The competitive inhibition model fitted to the pooled data for whole-body uptake explains about 94% of the variation in Sr2+ uptake and 71% in Ca2+ uptake, indicating a competitive type of interaction during the transport of these metal ions across the biological interfaces. The maximum uptake rate of Sr2+ (JmaxSr) was estimated to be 243.0 μmol/kg/h and that of Ca2+ (JmaxCa) 119.4 μmol/kg/h. The apparent Km for Sr2+ uptake increased greatly with the increase of Ca2+ concentration in water (186, 789, and 5,515 μM for 35, 348, and 3,480 μM Ca2+, respectively). Estimation of the true Km for Sr2+ uptake (KmSr) and its inhibitor constant for Ca2+ (KiCa) yielded the values of 96.3 and 28.5 μM, respectively. These values are very close to those obtained for Ca2+ uptake (KmCa = 24.9 and KiSr = 100.9 μM). This model provides a mechanistic description of the effect of calcium on strontium uptake from water and, vice versa, in carp.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1002/etc.5620190314
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
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    Toxicity of proton–metal mixtures in the field: Linking stream macroinvertebrate species diversity to chemical speciation and bioavailability (2010)
    Elsevier
    Details
    Publication Date: 2023-11-29
    Description: Understanding metal and proton toxicity under field conditions requires consideration of the complex nature of chemicals in mixtures. Here, we demonstrate a novel method that relates streamwater concentrations of cationic metallic species and protons to a field ecological index of biodiversity. The model WHAM-FTOX postulates that cation binding sites of aquatic macroinvertebrates can be represented by the functional groups of natural organic matter (humic acid), as described by the Windermere Humic Aqueous Model (WHAM6), and supporting field evidence is presented. We define a toxicity function (FTOX) by summing the products: (amount of invertebrate-bound cation) × (cation-specific toxicity coefficient, αi). Species richness data for Ephemeroptera, Plecoptera and Trichoptera (EPT), are then described with a lower threshold of FTOX, below which all organisms are present and toxic effects are absent, and an upper threshold above which organisms are absent. Between the thresholds the number of species declines linearly with FTOX. We parameterised the model with chemistry and EPT data for low-order streamwaters affected by acid deposition and/or abandoned mines, representing a total of 412 sites across three continents. The fitting made use of quantile regression, to take into account reduced species richness caused by (unknown) factors other than cation toxicity. Parameters were derived for the four most common or abundant cations, with values of αi following the sequence (increasing toxicity) H+ 〈 Al 〈 Zn 〈 Cu. For waters affected mainly by H+ and Al, FTOX shows a steady decline with increasing pH, crossing the lower threshold near to pH 7. Competition effects among cations mean that toxicity due to Cu and Zn is rare at lower pH values, and occurs mostly between pH 6 and 8.
    Type: Article , PeerReviewed
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
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    Enhanced olivine dissolution in seawater through continuous grain collisions (2023)
    Elsevier
    Details
    Publication Date: 2024-02-07
    Description: Carbon dioxide removal (CDR) technologies at a gigaton scale need to be developed and implemented within the next decades to keep global warming below 1.5 °C. Coastal enhanced silicate weathering is one of the proposed CDR techniques that aims to accelerate the natural process of CO2-sequestration during marine chemical weathering of silicate minerals. To this end, finely ground rock containing olivine (MgxFe2− xSiO4) could be dispersed in dynamic coastal environments, where local biotic and abiotic factors potentially enhance the weathering process. However, accurate predictions of the olivine dissolution rate and the associated CO2 sequestration under in situ conditions are currently lacking and ecosystem impacts remain to be assessed. Previously, it has been hypothesized that in situ grain collisions, induced by bed load transport due to currents and waves, could accelerate the in situ chemical weathering of olivine particles. To examine this, we investigated the effects of continuous grain tumbling on olivine dissolution in natural seawater. A 70-day experiment was conducted in which forsterite olivine sand was continuously tumbled in filtered seawater at different rotation speeds, and dissolution rates were measured on a weekly basis. Results showed that continuously tumbled olivine dissolved 8 to 19 times faster compared to stagnant (no rotation) conditions. Olivine dissolution was complete and stoichiometric (except for Ni release), air-seawater CO2 exchange was not significantly rate limiting, and minimal particle fragmentation and secondary mineral formation were observed. Hence, we infer that olivine weathering was mainly enhanced via advective pore water flushing, which limits saturation effects at the grain scale. Overall, this study provides evidence that ambient physical stresses in coastal environments could enhance marine silicate weathering, which has implications for both the natural silicon cycle as well as the use of enhanced coastal weathering of silicates as a CDR technique.
    Type: Article , PeerReviewed
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 5
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    (Table 1) Concentrations of organic pollutants in soil samples from Adélie penguin (Pygoscelis adeliae) colonies and reference sites, Hop Island, Antarctica (2007)
    PANGAEA
    In:  Supplement to: Roosens, Laurence; Van Den Brink, Nico W; Riddle, Martin J; Blust, Ronny; Neels, Hugo; Covaci, Adrian (2007): Penguin colonies as secondary sources of contamination with persistent organic pollutants. Journal of Environmental Monitoring, 9(8), 822, https://doi.org/10.1039/b708103k
    Details
    Publication Date: 2023-12-13
    Description: Although long-range atmospheric transport has been described as the predominant mechanism for exposing polar regions to persistent organic pollutants (POPs), recent studies have suggested that bird activity can also contribute substantially to contaminant levels in some environments. However, because the species so far reported have all been migratory, it has not been demonstrated conclusively whether locally elevated contamination represents transport from lower latitudes by the migrating birds or, alternatively, redistribution and concentration of contaminants that were already present in the high-latitude environments. The present study demonstrates, for the first time, that several POPs are present in elevated concentrations in an environment frequented by a non-migratory species (Adelie penguins) that spends its entire life in the Antarctic. Levels of POPs, such as p,p'-DDE, hexachlorobenzene (HCB), chlordanes (CHLs) and polychlorinated biphenyls (PCBs), were 10 to 100-fold higher in soil samples from penguin colonies than from reference areas. This significant difference is likely related to local penguin activity, such as a higher abundance of guano and the presence of bird carcasses. This hypothesis is also supported by a higher percentage of persistent congeners (PCB 99, 118, 138 and 153) in the soil from the colonies compared to the reference areas. This profile of PCB congeners closely matched profiles seen in penguin eggs or penguin blood.
    Keywords: alpha-Hexachlorocyclohexane; beta-Hexachlorocyclohexane; Carbon, organic, total; Chlordane; Chlordane, standard deviation; cis-Chlordane; DATE/TIME; Dichlorodiphenyltrichloroethane; Dichlorodiphenyltrichloroethane, standard deviation; gamma-Hexachlorocyclohexane; Gas chromatography - Mass spectrometry (GC-MS); Group; HAND; Hexachlorobenzene; Hexachlorobenzene, standard deviation; Hexachlorocyclohexane; Hexachlorocyclohexane, standard deviation; Hop_Is; International Polar Year (2007-2008); IPY; ortho,para-Dichlorodiphenyltrichloroethane; Oxychlordane; para,para-Dichlorodiphenyldichloroethane; para,para-Dichlorodiphenyldichloroethylene; para,para-Dichlorodiphenyltrichloroethane; Polybrominated diphenyl ethers; Polychlorinated biphenyl; Polychlorinated biphenyl, standard deviation; Prydz Bay; Sample amount; Sample ID; Sample type; Sampling by hand; trans-Chlordane; trans-Nonachlor
    Type: Dataset
    Format: text/tab-separated-values, 186 data points
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    DATA PANGAEA
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