| 1. |
- Li, L. S., et al.
(författare)
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CONFLICTING EFFECTS OF PREDATOR CUE AND OCEAN ACIDIFICATION ON THE MUSSEL MYTILUS CORUSCUS BYSSUS PRODUCTION
- 2015
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Ingår i: Journal of Shellfish Research. - : National Shellfisheries Association. - 0730-8000 .- 1943-6319. ; 34:2, s. 393-400
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the impact of ocean acidification and warming on communities and ecosystems is a researcher priority. This can only be achieved through a combination of experimental and field approaches that would allow developing a mechanistic understanding of impacts across level of biological organizations. Surprisingly, most published studies are still focusing on single species responses with little consideration for interspecific interactions. In this study, the impacts of a 3 days exposure to three parameters (temperature, pH, and presence/absence of the predator cue of the crab Charybdis japonica) and their interactions on an ecologically important endpoint were evaluated: the byssus production of the mussel Mytilus coruscus. Tested temperatures (25 degrees C and 30 degrees C) were within the present range of natural variability whereas pH (8.1, 7.7, and 7.4) covered present as well as near-future natural variability. As expected, the presence of the crab cue induced an antipredator response in Mytilus coruscus (significant 10% increase in byssus secretion rate, 22% increase in frequency of shed byssus, and 30% longer byssus). Decreased pH but not temperature had a significant negative impact on the same endpoints (up to a 17% decrease in byssus secretion rate, 40% decrease in frequency of shed byssus, and 10% shorter byssus at pH 7.3 as compared with pH 8.1) with no significant interactions between the three tested parameters. In this study, it has been hypothesized that pH and predator cue have different modes of action and lead to conflicting functional responses (escape response versus stronger attachment). Functional consequences for ecosystem dynamics still need to be investigated.
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| 2. |
- Pernet, Fabrice, et al.
(författare)
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Cracking the myth: Bivalve farming is not a CO2 sink
- 2024
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Ingår i: REVIEWS IN AQUACULTURE. - 1753-5123 .- 1753-5131.
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Forskningsöversikt (refereegranskat)abstract
- Bivalve farming was usually considered as a CO2 source through respiration and calcification, but recent studies suggest its potential as a CO2 sink, prompting exploration of its inclusion in carbon markets. Here we reviewed the scientific basis behind this idea and found that it is not supported by observational and experimental studies. This idea indeed arises from carbon budget models that are based on theoretical misconceptions regarding seawater carbonate chemistry. The main misunderstanding consists of assuming that the carbon trapped in the shell originates from atmospheric CO2 when it mostly comes from (bi)carbonate ions. While these ions originate from atmospheric CO2 through the erosion of minerals over geological time scales, their incorporation into shells does not prompt short-term CO2 compensation. The opposite occurs-calcification releases CO2 in seawater and limits or even prevents the uptake of atmospheric CO2. Some authors suggest that considering the bivalve farm ecosystem could change the perspective on the source/sink issue but there is no evidence for that now. Most ecosystem-based carbon budget models rely on several unverified assumptions and estimates. Although challenging, field measurements must be conducted for monitoring, reporting, and verifying atmospheric CO2 uptake before qualifying for carbon credits. To achieve scientific consensus, we need reinforcing measurement-based studies of CO2 fluxes in shellfish ecosystems, integrating carbon balance models with observational and experimental science, and fostering interdisciplinary collaboration. Although bivalve farming provides numerous environmental benefits and is vital for sustainable aquaculture, there is currently no evidence that it contributes to CO2 capture.
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| 3. |
- Schagerström, Ellen, et al.
(författare)
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Controlled spawning and rearing of the sea cucumber, Parastichopus tremulus
- 2022
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Ingår i: Journal of the World Aquaculture Society. - : Wiley. - 0893-8849 .- 1749-7345. ; 53:1, s. 224-240
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Tidskriftsartikel (refereegranskat)abstract
- The red sea cucumber, Parastichopus tremulus, a cold water species with commercial potential, has recently attracted attention for wild harvest as well as for potential use in integrated multi-trophic aquaculture in Scandinavian countries. Overharvesting has put natural stocks of sea cucumbers at risk in several countries. Our goal was to develop a rearing protocol for P. tremulus to enable sustainable production of this species. This study presents results from spawning and larval rearing conducted in both Norway (NO) and Sweden (SWE) during May-August 2019. We describe spawning induction and behavior, fertilization success, embryonic and auricularia larval development rate for this species under laboratory conditions. The larvae were fed a mixture of three species of live microalgae (SWE) and algal paste (NO). Larval development rate and survival were monitored at four different temperatures (7, 10, 13, and 16 degrees C). Results showed faster development with increasing temperature. Daily food consumption rate was highest at the highest temperature. The combined effects of temperature and food availability on survival were investigated for the same four temperatures and three different feed concentrations. Only food availability affected the mortality rate, with the highest mortality in the low feeding regime of 1,000-2,000 cells ml(-1) day(-1).
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| 4. |
- Xie, Z., et al.
(författare)
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Physiological responses to salinity change and diel-cycling hypoxia in gills of Hong Kong oyster Crassostrea hongkongensis
- 2023
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 570
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Tidskriftsartikel (refereegranskat)abstract
- Global climate change is a frequent cause of salinity fluctuation in seawater, especially in aquaculture sites. Moreover, anthropologic activities often cause seawater eutrophication with the consequence that hypoxia ap-pears often during nighttime. The Hong Kong oyster Crassostrea hongkongensis, as a species that inhabits estuarine and coastal waters, is faced with such challenges. In this study, oyster physiological changes were considered to be closely related to hypoxia and salinity changes. Physiological indices were examined in Hong Kong oysters by employing six treatments to shed light into the effects of diel-cycling hypoxia (periodical hypoxia) and salinity change. Three salinities (10%o, low salinity; 25%o, normal salinity; and 35%o, high salinity) and two types of dissolved oxygen (normoxia, 6 mg/L throughout the day) and periodical hypoxic condition (6 mg/L at daytime for 12 h and 2 mg/L at nighttime for 12 h) were set. After 14-and 28-day exposures, gill tissues were sampled to detect changes in gill ATP production, mitochondrial membrane potential (MMP), mitochondrial reactive oxygen species production (ROS), and gill respiratory metabolic enzymes. Results indicated that periodical hypoxia and salinity change led to increased hexokinase (HK) and pyruvate kinase (PK) (p < 0.05). By contrast, they had no significant effect on mitochondrial number (MN). Adenosine-triphosphate (ATP) production only increased in the early exposure. In addition, low salinity with periodical hypoxia resulted in decreased MMP, lactate dehy-drogenase (LDH), and succinate dehydrogenase (SDH, p < 0.05). On the contrary, periodical hypoxia with high salinity led to increases in ATP and ROS and decreases in SDH, MMP, and LDH (p < 0.05). These results revealed that when diel-cycling hypoxia occurs with salinity change, the gill metabolism of Hong Kong oysters are gradually dominated by glycolysis while aerobic respiration decreases. Moreover, gill functions could be affected although energy accumulation exists during early exposure. Therefore, long-term exposure to periodical hypoxia with salinity change poses risk to the health and growth of Hong Kong oysters, impairing oyster aquaculture and coastal ecosystem health.
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