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- Baden, Susanne P., 1952, et al.
(author)
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Accumulation and elimination kinetics of manganese from different tissues of the Norway lobster Nephrops norvegicus (L.)
- 1999
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In: Aquatic Toxicology. - 0166-445X. ; 46:2, s. 127-137
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Journal article (peer-reviewed)abstract
- The exposure of marine benthic animals to dissolved manganese (Mn) occurs from metalliferous outlets or the enhanced flux of dissolved manganese from sediments during hypoxia. A prerequisite to valid interpretation of manganese concentrations measured in animals in situ is a thorough understanding of accumulation and elimination rates of this metal by relevant target tissues in organisms exposed to environmentally realistic manganese concentrations. Norway lobster, Nephrops norvegicus, accumulated manganese when exposed to solutions of < 0.06 (background), 5 and 10 mg Mn l(-1) for 20 days and was allowed to eliminate any accumulated manganese in undosed sea water for a further 20 days. During this period individual N. norvegicus were dissected into a number of components (brain, ventral ganglion, haemolymph, midgut gland, gills and exoskeleton) and the manganese concentration of each was analysed. Manganese accumulation reached a plateau after 1.25 days in all tissues except for midgut gland, which continued to accumulate manganese during the entire exposure period. In general, the manganese elimination was significantly slower than accumulation and reached a plateau after 1.25-2.5 days (except the gills) following exposure to clean sea water. The accumulation factor (AF), when compared to maximum concentrations in control and exposed animals, was highest in the haemolymph (x 88) followed by nerve tissue (x 22) at the 10 mg Mn l(-1) exposure. The concentration factor (CF), when comparing manganese accumulation in tissues (wet weight) with exposure concentration, was 1.2-3.5 and for most tissues was similar for both exposure concentrations or slightly higher in the 5 mg Mn l(-1) exposure-indicating net accumulation of manganese in all tissues with a saturation effect with increasing exposure concentrations. Thus, from these experiments it may be concluded that measured manganese concentrations in N. norvegicus give an indication of recent exposure to manganese concentrations in the bottom waters of their habitats. (C) 1999 Elsevier Science B.V. All rights reserved.
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| 4. |
- Eriksson, Susanne P., 1964, et al.
(author)
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Behaviour and tolerance to hypoxia in juvenile Norway lobster (Nephrops norvegicus) of different ages
- 1997
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In: Marine Biology. - 0025-3162. ; 128:1, s. 49-54
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Journal article (peer-reviewed)abstract
- The annual occurrence of hypoxia (<25% oxygen saturation) in the bottom waters along the Swedish west coast coincides with the postlarval settlement of Norway lobster, Nephrops norvegicus (L.). This study investigates behaviour and the experimental effects of low oxygen concentrations in juvenile N. norvegicus of different ages. All experimental individuals were reared to the juvenile (postlarval) stage in the laboratory and then given sediment as a substratum. Behavioural responses to low oxygen concentrations were tested in early and late Postlarvae 1 exposed to normoxia (>80% oxygen saturation, pO(2) > 16.7 kPa), moderate hypoxia (30% oxygen saturation, pO(2) = 6.3 kPa) and hypoxia (25% oxygen saturation, pO(2) = 5.2 kPa). The experiments were run for a maximum period of 24 h or until individuals died. Behaviour was studied using sequential video recordings of four behavioural activities: digging, walking, inactivity or flight (escape swimming up into the water column). Behaviour and mortality changed with lowered oxygen concentrations; energetically costly activities (such as walking) were reduced, and activity in general declined. In normoxia, juveniles initially walked and then burrowed, but when exposed to hypoxia they were mainly inactive with occasional outbursts of escape swimming. To increase oxygen availability the juveniles were observed to raise their bodies on stilted legs (similar to adults in hypoxic conditions), but oxygen saturations of 25% were lethal within 24 h. The results suggest that the main gas exchanges of early postlarval stages occur over the general body surface. Burrowing behaviour was tested in Postlarvae 1 and 2 of different ages held in >80% oxygen saturation for 1 wk. The difference in time taken to complete a V-shaped depression or a U-shaped burrow was measured. The results showed a strong negative relationship between postlarval age and burrowing time, but all individuals made a burrow. Juveniles were more sensitive to hypoxia than adults. Thus, the possible consequences of episodic hypoxia for the recruitment of Nephrops norvegicus and for the recolonization of severely affected areas are discussed.
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| 5. |
- Eriksson, Susanne P., 1964, et al.
(author)
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Manganese in the haemolymph and tissues of the Norway lobster, Nephrops norvegicus (L.), along the Swedish west coast, 1993-1995
- 1998
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In: Hydrobiologia. - 0018-8158. ; 376, s. 255-264
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Journal article (peer-reviewed)abstract
- Spatial and temporal differences in manganese levels in Norway lobsters, Nephrops norvegicus, were compared with the concentrations of manganese in their environment. Animals were collected twice yearly (spring and autumn) from seven stations along the Swedish west coast and from one site in the Faroe Islands, during 1993-94, and analysed for manganese tissue concentration and content. Animals were also collected from the Swedish stations in the autumn of 1995 and compared with animals from a stressful environment, frequently exposed to hypoxia. There were large spatial differences and the animals collected in the Faroe Islands contained (in most tissues) one order of magnitude less manganese than the animals collected along the Swedish west coast. The manganese level of the haemolymph correlated most closely with the manganese concentration the animal was exposed to in the field. The manganese concentration of the female gonad tissue did however not differ with space nor time and remained stable around 5.1 mu g Mn g(-1) dw tissue throughout the investigation. Animals taken from an area with known repeated hypoxia in the bottom water, had high levels of manganese in especially the gills. Their mean manganese concentration was over 20 times higher (1560 mu g Mn g(-1) dw tissue) than the manganese concentration in animals from the other Swedish stations. They also had more than threefold the amount of manganese in the brain, giving a mean concentration of 193 mu g Mn g(-1) dw tissue.
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| 6. |
- Eriksson, Susanne P., 1964, et al.
(author)
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Stress Biology and Immunology in Nephrops norvegicus
- 2013
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In: Advances in Marine Biology. - : Elsevier. - 0065-2881. ; 64, s. 149-200
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Journal article (peer-reviewed)abstract
- The Norway lobster Nephrops norvegicus lives at low-light depths, in muddy substrata of high organic content where water salinities are high and fluctuations in temperature are moderate. In this environment, the lobsters are naturally exposed to a number of potential stressors, many of them as a result of the surficial breakdown of organic material in the sediment. This process (early diagenesis) creates a heterogeneous environment with temporal and spatial fluctuations in a number of compounds such as oxygen, ammonia, metals, and hydrogen sulphide. In addition to this, there are anthropogenically generated stressors, such as human-induced climate change (resulting in elevated temperature and ocean acidification), pollution and fishing. The lobsters are thus exposed to several stressors, which are strongly linked to the habitat in which the animals live. Here, the capacity of Nephrops to deal with these stressors is summarised. Eutrophication-induced hypoxia and subsequent metal remobilisation from the sediment is a well-documented effect found in some wild Nephrops populations. Compared to many other crustacean species, Nephrops is well adapted to tolerate periods of hypoxia, but prolonged or severe hypoxia, beyond their tolerance level, is common in some areas. When the oxygen concentration in the environment decreases, the bioavailability of redox-sensitive metals such as manganese increases. Manganese is an essential metal, which, taken up in excess, has a toxic effect on several internal systems such as chemosensitivity, nerve transmission and immune defence. Since sediment contains high concentrations of metals in comparison to sea water, lobsters may accumulate both essential and non-essential metals. Different metals have different target tissues, though the hepatopancreas, in general, accumulates high concentrations of most metals. The future scenario of increasing anthropogenic influences on Nephrops habitats may have adverse effects on the fitness of the animals.
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| 7. |
- Eriksson, Susanne P., et al.
(author)
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Stress biology and immunology in Nephrops norvegicus
- 2013
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In: The ecology and biology of Nephrops norvegicus. - Amsterdam : Academic Press. ; , s. 149-200
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Book chapter (pop. science, debate, etc.)abstract
- The Norway lobster Nephrops norvegicus lives at low-light depths, in muddy substrata of high organic content where water salinities are high and fluctuations in temperature are moderate. In this environment, the lobsters are naturally exposed to a number of potential stressors, many of them as a result of the surficial breakdown of organic material in the sediment. This process (early diagenesis) creates a heterogeneous environment with temporal and spatial fluctuations in a number of compounds such as oxygen, ammonia, metals, and hydrogen sulphide. In addition to this, there are anthropogenically generated stressors, such as human-induced climate change (resulting in elevated temperature and ocean acidification), pollution and fishing. The lobsters are thus exposed to several stressors, which are strongly linked to the habitat in which the animals live. Here, the capacity of Nephrops to deal with these stressors is summarised. Eutrophication-induced hypoxia and subsequent metal remobilisation from the sediment is a well-documented effect found in some wild Nephrops populations. Compared to many other crustacean species, Nephrops is well adapted to tolerate periods of hypoxia, but prolonged or severe hypoxia, beyond their tolerance level, is common in some areas. When the oxygen concentration in the environment decreases, the bioavailability of redox-sensitive metals such as manganese increases. Manganese is an essential metal, which, taken up in excess, has a toxic effect on several internal systems such as chemosensitivity, nerve transmission and immune defence. Since sediment contains high concentrations of metals in comparison to sea water, lobsters may accumulate both essential and non-essential metals. Different metals have different target tissues, though the hepatopancreas, in general, accumulates high concentrations of most metals. The future scenario of increasing anthropogenic influences on Nephrops habitats may have adverse effects on the fitness of the animals.
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| 9. |
- Nilsson Sköld, Helen, 1970, et al.
(author)
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Motoric impairment following manganese exposure in asteroide chinoderms
- 2015
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In: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 167, s. 31-37
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Journal article (peer-reviewed)abstract
- In the oceans, naturally occurring manganese (Mn) is released from the sediments during events of hypoxia. While neuro- and immuno-toxic effects of bioavailable manganese are well documented for crustaceans, studies of similar effects of manganese on other marine invertebrates are comparatively few. Here, we developed a new functional test “the repeated turning assay” to investigate if manganese exposure at ∼12 mg L−1 affected motoric behaviour of two asteroid echinoderms, the Common sea star, Asterias rubens, and the Black brittle star, Ophiocomina nigra. By measuring of the turning-over capacity, from dorsal to ventral position, after one and two weeks of manganese exposure, we showed that for both species Mn exposure significantly delayed the ability to turn. After a recovery period of two weeks, the capacity of turning-over was not restored to that of unexposed animals neither for A. rubens nor for O. nigra. Further investigation of sea stars showed that Mn accumulated ∼5 fold in the tube feet, organs involved in their turning-over activity, and the high concentration remained after the recovery period. In the tube feet we also recorded an increased activity of acetylcholinesterase (AChE), here used as a proxy for neuromuscular disturbances. The results indicated that Mn induces neuromuscular disturbance in echinoderms which is important news, given that previous studies have concluded that adult echinoderms are relatively tolerant to Mn.
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