| 1. |
- van Duyl, F. C., et al.
(författare)
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Dark CO2 fixation into phospholipid-derived fatty acids by the cold-water coral associated sponge Hymedesmia (Stylopus) coriacea (Tisler Reef, NE Skagerrak)
- 2020
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Ingår i: Marine Biology Research. - : Informa UK Limited. - 1745-1000 .- 1745-1019. ; 16:1, s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- Many cold-water sponges harbour microorganisms of which the role in the sponge host remains enigmatic. Here, we show a transfer of fixed inorganic carbon by sponge-associated microbes to its host, the cold-water coral encrusting sponge Hymedesmia (Stylopus) coriacea. Sponge were collected at approx. 100 m depth and incubated for 1.5–2.5 days with 13C labelled dissolved inorganic carbon (DIC) as tracer. Total DIC fixation rates ranged from 0.03–0.11 mmol C × mmol Csponge × d−1. 13C-tracer was recovered in bacterial-specific (i.e. short and branched) and sponge-specific (very long-chained) phospholipid-derived fatty acids (PLFA's), but was not incorporated into archaeal lipids. 13C-incorporation in biomarkers such as C16:1w7c and C18:1w7c indicated that nitrifying and/or sulphur-oxidizing bacteria (chemoautotrophs) were likely active in the sponge. Trophic transfer of microbially-fixed carbon to the sponge host was confirmed by recovery of label in very long chain fatty acids (VLCFA's) including C26:2 and C26:3. Tracer accumulation into several VLCFA's continued after removal of 13C-DIC, while tracer in most bacteria-specific PLFA's declined, indicating a transfer and elongation of bacterial-specific PLFA's to sponge-specific PLFA's. This implies that PLFA precursors released from chemo- as well as heterotrophic microbes in sponges contributed to the synthesis of VLCFA's, identifying sponge-associated bacteria as symbionts of the sponge. © 2020, © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
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| 2. |
- Van Oevelen, D., et al.
(författare)
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Niche overlap between a cold-water coral and an associated sponge for isotopicallyenriched particulate food sources
- 2018
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 13:3
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Tidskriftsartikel (refereegranskat)abstract
- The cold-water coral Lophelia pertusa is an ecosystem engineer that builds reef structures on the seafloor. The interaction of the reef topography with hydrodynamics is known to enhance the supply of suspended food sources to the reef communities. However, the reef framework is also a substrate for other organisms that may compete for the very same suspended food sources. Here, we used the passive suspension feeder Lophelia pertusa and the active suspension feeding sponge Hymedesmia coriacea as model organisms to study niche overlap using isotopically-enriched algae and bacteria as suspended food sources. The coral and the sponge were fed with a combination of 13C-enriched bacteria/15Nenriched algae or 15N-enriched bacteria/13C-enriched algae, which was subsequently traced into bulk tissue, coral skeleton and dissolved inorganic carbon (i.e. respiration). Both the coral and the sponge assimilated and respired the suspended bacteria and algae, indicating niche overlap between these species. The assimilation rates of C and N into bulk tissue of specimens incubated separately were not significantly different from assimilation rates during incubations with co-occurring corals and sponges. Hence, no evidence for exploitative resource competition was found, but this is likely due to the saturating experimental food concentration that was used. We do not rule out that exploitative competition occurs in nature during periods of low food concentrations. Food assimilation and respiration rates of the sponge were almost an order of magnitude higher than those of the coldwater coral. We hypothesize that the active suspension feeding mode of the sponge explains the observed differences in resource uptake as opposed to the passive suspension feeding mode of the cold-water coral. These feeding mode differences may set constraints on suitable habitats for cold-water corals and sponges in their natural habitats. © 2018 van Oevelen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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| 3. |
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| 4. |
- Larsson, Ann I., 1965, et al.
(författare)
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Tolerance to long-term exposure of suspended benthic sediments and drill cuttings in the cold-water coral Lophelia pertusa
- 2013
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Ingår i: Marine Pollution Bulletin. - : Elsevier BV. - 0025-326X. ; 70:1-2, s. 176-188
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Tidskriftsartikel (refereegranskat)abstract
- The cold-water coral Lophelia pertusa was exposed to suspended particles (<63 mu m) for 12 weeks. Skeletal growth was significantly lower under exposure concentrations of similar to 25 mg l(-1) than similar to 5 mg l(-1) and there was a trend of lower growth rates when exposed to water-based drill cuttings than to natural benthic sediment. Polyp extension was less in corals exposed to higher material concentrations, which provides a possible explanation for observed skeletal growth differences between particle concentrations. Particle exposure had no significant impact on respiration or proportions of tissue and fatty acids in corals. The volume of additional cleaning mucus released by exposed corals was low and release did not significantly affect coral energy expenditure. Our results indicate that L. pertusa polyps can deal comparatively well with enhanced particle deposition rates and suspended matter concentrations. However, a small pilot experiment indicated that coral larvae might be particularly vulnerable to high particle concentrations. (c) 2013 Elsevier Ltd. All rights reserved.
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| 5. |
- Mueller, C. E., et al.
(författare)
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Opportunistic feeding on various organic food sources by the cold-water coral Lophelia pertusa
- 2014
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 11:1, s. 123-133
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Tidskriftsartikel (refereegranskat)abstract
- The ability of the cold-water coral Lophelia pertusa to exploit different food sources was investigated under standardized conditions in a flume. The tested food sources, dissolved organic matter (DOM, added as dissolved free amino acids), bacteria, algae, and zooplankton (Artemia) were deliberately enriched in 13C and 15N. The incorporation of 13C and 15N was traced into bulk tissue, fatty acids, hydrolysable amino acids, and the skeleton (13C only) of L. pertusa. Incorporation rates of carbon (ranging from 0.8–2.4 μg C g−1 DW d–1) and nitrogen (0.2–0.8 μg N g−1 DW d–1) into coral tissue did not differ significantly among food sources indicating an opportunistic feeding strategy. Although total food assimilation was comparable among sources, subsequent food processing was dependent on the type of food source ingested and recovery of assimilated C in tissue compounds ranged from 17% (algae) to 35% (Artemia). De novo synthesis of individual fatty acids by L. pertusa occurred in all treatments as indicated by the 13C enrichment of individual phospholipid-derived fatty acids (PLFAs) in the coral that were absent in the added food sources. This indicates that the coral might be less dependent on its diet as a source of specific fatty acids than expected, with direct consequences for the interpretation of in situ observations on coral nutrition based on lipid profiles.
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| 6. |
- Mueller, C. E., et al.
(författare)
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The Symbiosis between Lophelia pertusa and Eunice norvegica Stimulates Coral Calcification and Worm Assimilation
- 2013
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:3
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the interactions between the cold-water coral Lophelia pertusa and its associated polychaete Eunice norvegica by quantifying carbon (C) and nitrogen (N) budgets of tissue assimilation, food partitioning, calcification and respiration using 13C and 15N enriched algae and zooplankton as food sources. During incubations both species were kept either together or in separate chambers to study the net outcome of their interaction on the above mentioned processes. The stable isotope approach also allowed us to follow metabolically derived tracer C further into the coral skeleton and therefore estimate the effect of the interaction on coral calcification. Results showed that food assimilation by the coral was not significantly elevated in presence of E. norvegica but food assimilation by the polychaete was up to 2 to 4 times higher in the presence of the coral. The corals kept assimilation constant by increasing the consumption of smaller algae particles less favored by the polychaete while the assimilation of Artemia was unaffected by the interaction. Total respiration of tracer C did not differ among incubations, although E. norvegica enhanced coral calcification up to 4 times. These results together with the reported high abundance of E. norvegica in cold-water coral reefs, indicate that the interactions between L. pertusa and E. norvegica can be of high importance for ecosystem functioning.
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| 7. |
- Orejas, C, et al.
(författare)
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Cold-water corals in aquaria: advances and challenges. A focus on the Mediterranean
- 2019
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Ingår i: Mediterranean Cold-Water Corals: Past, Present and Future. - : Springer. - 2213-719X. - 9783319916071
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Bokkapitel (refereegranskat)abstract
- Knowledge on basic biological functions of organisms is essential to understand not only the role they play in the ecosystems but also to manage and protect their populations. The study of biological processes, such as growth, reproduction and physiology, which can be approached in situ or by collecting exemplars and rearing them in aquaria, is particularly challenging for deep-sea organisms such as cold-water corals (CWCs). Present experimental work and monitoring of deep-sea populations is still a chimera. Only a handful of research institutes or companies have been able to install in situ marine observatories in the Mediterranean Sea or elsewhere, which facilitate for a continuous monitoring of deep-sea ecosystems. Hence, today’s best way to obtain basic biological information on these organisms is (1) working with collected samples and analysing them post-mortem and / or (2) cultivating corals in aquaria in order to monitor biological processes and investigate coral behaviour and physiological responses under different experimental treatments. The first challenging aspect is the collection process, which implies the use of oceanographic research vessels in most occasions, since these organisms inhabit areas between ca. 150 m to more than 1,000 m depth, and specific sampling gears. The next challenge is the maintenance of the animals on board (in situations where cruises may take weeks) and their transport to home laboratories. Maintenance in the home labs is also extremely challenging since special conditions and set ups are needed to conduct experimental studies to obtain information on the biological processes of these animals. The complexity of the natural environment from which the corals were collected cannot be exactly replicated within the laboratory setting; a fact which has led some researchers to question the validity of work and conclusions drawn from such undertakings. It is evident that aquaria experiments cannot perfectly reflect the real environmental and trophic conditions where these organisms occur, but: (1) in most cases we do not have the possibility to obtain equivalent in situ information and (2) even with limitations, they produce relevant information about 117 the biological limits of the species, which is especially valuable when considering potential future climate change scenarios. This chapter includes many contributions from different authors and it intends to be both, a practical “handbook” for conducting CWC aquaria work, while at the same time, to offer an overview on the CWC research conducted in Mediterranean labs equipped with aquaria infrastructure. Experiences from Atlantic and Pacific laboratories with extensive experience with CWC work have also contributed to this chapter, as their procedures are valuable to any researcher interested in conducting experimental work with CWC in aquaria. It was impossible to include contributions from all labs in the world currently working experimentally with CWCs in the laboratory, but at the conclusion of the chapter we attempt, to our best of our knowledge, to supply a list of laboratories with operational CWC aquaria facilities.
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| 8. |
- Purser, A., et al.
(författare)
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The influence of flow velocity and food concentration on Lophelia pertusa (Scleractinia) zooplankton capture rates
- 2010
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Ingår i: Journal of Experimental Marine Biology and Ecology. - 0022-0981. ; 395:1-2, s. 55-62
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Tidskriftsartikel (refereegranskat)abstract
- Lophelia pertusa is the most significant framework building scleractinian coral in European seas, yet the reproductive strategy, longevity, growth and food capture rates for the species remain poorly understood. In this study an experimental investigation into the ability of L pertusa to capture zooplankton from suspension was conducted. By direct ROV sampling approximately 350 L pertusa polyps were collected from the Tisler reef, Norway and maintained under temperature controlled conditions in recirculating flumes. These polyps were subdivided into three replicate groups of similar to 120 polyps and maintained in waters with flow velocities of 2.5 cm s(-1) or 5.0 cm s(-1). Suspended Artemia sauna nauplii food concentrations of between 345 and 1035 A. sauna l(-1) were introduced. L pertusa net capture rates were assessed by monitoring the reduction in suspended A. sauna concentration in each flume over 24 h. Maximum net capture rates were higher in flumes with a 2.5 cm s(-1) flow regime, at 73.3 +/- 2.0 A. salina polyp(-1) h(-1) (mean +/- SD) than those with 5 cm s(-1) flow (19.8 +/- 11.8 A. sauna polyp(-1) h(-1)). Maximum net capture rates were lower in flumes with A. sauna densities of <690 A. salina l(-1) than in flumes with higher food densities under comparable flow velocities. The maximum net capture rates observed represent maximum carbon capture rates of 66.4 +/- 2.0 mu g C polyp(-1) h(-1) and 17.9 +/- 10.7 mu g C polyp(-1) h(-1) under 2.5 and 5 cm(-1) s(-1) flow speeds respectively. The results of this study indicate that L pertusa captures zooplankton more efficiently under slower flow velocities. (C) 2010 Elsevier B.V. All rights reserved.
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| 9. |
- van Oevelen, D., et al.
(författare)
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Food selectivity and processing by the cold-water coral Lophelia pertusa
- 2016
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 13:20, s. 5789-5798
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Tidskriftsartikel (refereegranskat)abstract
- Cold-water corals form prominent reef ecosystems along ocean margins that depend on suspended resources produced in surface waters. In this study, we investigated food processing of C-13 and N-15 labelled bacteria and algae by the cold-water coral Lophelia pertusa. Coral respiration, tissue incorporation of C and N and metabolically derived C incorporation into the skeleton were traced following the additions of different food concentrations (100, 300, 1300 mu g CL-1) and two ratios of suspended bacterial and algal biomass (1 : 1, 3 : 1). Respiration and tissue incorporation by L. pertusa increased markedly following exposure to higher food concentrations. The net growth efficiency of L. pertusa was low (0.08 +/- 0.03), which is consistent with its slow growth rate. The contribution of algae and bacteria to total coral assimilation was proportional to the food mixture in the two lowest food concentrations, but algae were preferred over bacteria as a food source at the highest food concentration. Similarly, the stoichiometric uptake of C and N was coupled in the low and medium food treatment, but was uncoupled in the high food treatment and indicated a comparatively higher uptake or retention of bacterial carbon as compared to algal nitrogen. We argue that behavioural responses for these small-sized food particles, such as tentacle behaviour, mucus trapping and physiological processing, are more likely to explain the observed food selectivity as compared to physical-mechanical considerations. A comparison of the experimental food conditions to natural organic carbon concentrations above CWC reefs suggests that L. pertusa is well adapted to exploit temporal pulses of high organic matter concentrations in the bottom water caused by internal waves and downwelling events.
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