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ronald osinga
Wageningen University, Aquaculture and Fisheries Group, Faculty Member
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Research Interests: Zoology, Animal Science, Plant Biology, Biology, Ecology, and 4 moreIncubation, Predation, Coral, and Brine shrimp
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R script for daily detritus production as percentage of body weight for various species and shedder types
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Percentage of proliferating choanocytes in Halisarca caerulea specimens, incubated with BrdU for either 6 hours or 10 hours
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R scripts for percentage of proliferating choanocyte and mesohyl cells per individual
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This mini‐review evaluates the use of marine sponges in integrated culture systems, two decades after the idea was first proposed. It was predicted that the concept would provide a double benefit: sponges would grow faster under higher... more
This mini‐review evaluates the use of marine sponges in integrated culture systems, two decades after the idea was first proposed. It was predicted that the concept would provide a double benefit: sponges would grow faster under higher organic loadings, and filtration by sponges would improve water quality. It is promising that the growth of some commercially interesting sponges is indeed faster in organically enriched areas. The applicability of sponges as filters for undesired microorganisms has been confirmed in laboratory studies. However, upscaled farming studies need to be done to demonstrate the value of sponges for in situ bioremediation of sewage discharge or waste produced by fish cages. In addition, a new idea is presented – the use of sponges as an engine to convert dissolved organic matter (DOM) into particulate organic matter (POM) that can be consumed by deposit feeders through a chain of processes termed the sponge loop. A theoretical design of an integrated culture ...
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Sponges are ubiquitous components of various deep-sea habitats, including cold water coral reefs and deep-sea sponge grounds. Despite being surrounded by oligotrophic waters, these ecosystems are known to be hotspots of biodiversity and... more
Sponges are ubiquitous components of various deep-sea habitats, including cold water coral reefs and deep-sea sponge grounds. Despite being surrounded by oligotrophic waters, these ecosystems are known to be hotspots of biodiversity and carbon cycling. To assess the role of sponges in the carbon cycling of deep-sea ecosystems, we studied the energy budgets of six dominant deep-sea sponges (the hexactinellid species Vazella pourtalesi, and demosponge species Geodia barretti, Geodia atlantica, Craniella zetlandica, Hymedesmia paupertas and Acantheurypon spinispinosum) in an ex situ aquarium setup. Additionally, we determined morphological metrics for all species (volume, dry weight (DW), wet weight (WW), carbon (C) content, and ash-free dry weight (AFDW)) and provide species-specific conversion factors. Oxygen (O2) removal rates averaged 3.3 ± 2.8 µmol O2 DWsponge h−1 (all values mean ± SD), live particulate (bacterial and phytoplankton) organic carbon (LPOC) removal rates averaged 0....
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To support the successful application of sponges for water purification and collagen production, we evaluated the effect of depth on sponge morphology, growth, physiology, and functioning. Specimens of Eastern Mediterranean populations of... more
To support the successful application of sponges for water purification and collagen production, we evaluated the effect of depth on sponge morphology, growth, physiology, and functioning. Specimens of Eastern Mediterranean populations of the sponge Chondrosia reniformis (Nardo, 1847) (Demospongiae, Chondrosiida, Chondrosiidae) were reciprocally transplanted between 5 and 20 m depth within the Kaş-Kekova Marine Reserve Area. Control sponges at 5 m had fewer but larger oscula than their conspecifics at 20 m, and a significant inverse relationship between the osculum density and size was found in C. reniformis specimens growing along a natural depth gradient. Sponges transplanted from 20 to 5 m altered their morphology to match the 5 m control sponges, producing fewer but larger oscula, whereas explants transplanted from 5 to 20 m did not show a reciprocal morphological plasticity. Despite the changes in morphology, the clearance, respiration, and growth rates were comparable among al...
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Effects of depth and turbidity on the in situ pumping activity of the Mediterranean sponge Chondrosia reniformis (Nardo, 1847) were characterized by measuring osculum diameter, oscular outflow velocity, osculum density per sponge and... more
Effects of depth and turbidity on the in situ pumping activity of the Mediterranean sponge Chondrosia reniformis (Nardo, 1847) were characterized by measuring osculum diameter, oscular outflow velocity, osculum density per sponge and sponge surface area at different locations around the Bodrum peninsula (Turkey). Outflow velocity was measured using a new method based on video analysis of neutrally buoyant particles moving in the exhalant stream of sponge oscula, which yielded results that were in good comparison to other studies. Using the new method, it was shown that for C. reniformis, oscular outflow had a location-dependent, in most cases positive relationship with oscular size: bigger oscules process more water per cm2 of osculum surface. Turbidity and depth both affected sponge pumping in a negative way, but for the locations tested, the effect of depth was more profound than the effect of turbidity. Depth affected all parameters investigated except sponge size, whereas turbid...
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In this study, novel methods were tested to culture the collagen-rich sponge Chondrosia reniformis Nardo, 1847 (Demospongiae, Chondrosiida, Chondrosiidae) in the proximity of floating fish cages. In a trial series, survival and growth of... more
In this study, novel methods were tested to culture the collagen-rich sponge Chondrosia reniformis Nardo, 1847 (Demospongiae, Chondrosiida, Chondrosiidae) in the proximity of floating fish cages. In a trial series, survival and growth of cultured explants were monitored near a polluted fish farm and a pristine control site. Attachment methods, plate materials, and plate orientation were compared. In a first trial, chicken wire-covered polyvinyl chloride (PVC) was found to be the most suitable substrate for C. reniformis (100% survival). During a second trial, survival on chicken wire-covered PVC, after six months, was 79% and 63% for polluted and pristine environments, respectively. Net growth was obtained only on culture plates that were oriented away from direct sunlight (39% increase in six months), whereas sponges decreased in size when sun-exposed. Chicken wire caused pressure on explants and it resulted in unwanted epibiont growth and was therefore considered to be unsuitable ...
Research Interests: Marine Biology, Chemistry, Marine Ecology, Marine Aquaculture, Marine Science, and 13 moreAquaculture, Medicine, Sponges, Mariculture, Marine Biology and Oceanography, Sponge, Sponges and Marine Invertebrates, Integrated multitrophic aquaculture, Benthic invertebrates, Marine Sponges, Marine Drugs, Integrated Multi-Trophic Aquaculture, and Pharmacology and pharmaceutical sciences
Rates of dark respiration and net photosynthesis were measured on six replicate clonal fragments of the stony coral Galaxea fascicularis (Linnaeus 1767), which were incubated under twelve different combinations of dissolved oxygen (20%,... more
Rates of dark respiration and net photosynthesis were measured on six replicate clonal fragments of the stony coral Galaxea fascicularis (Linnaeus 1767), which were incubated under twelve different combinations of dissolved oxygen (20%, 100% and 150% saturation), dissolved carbon dioxide (9.5 and 19.1 μmol L(-1)) and water flow (1-1.6 cm s(-1) versus 4-13 cm s(-1)) in a repeated measures design. Dark respiration was enhanced by increased flow and increased oxygen saturation in an interactive way, which relates to improved oxygen influx into the coral tissue. Oxygen saturation did not influence net photosynthesis: neither hypoxia nor hyperoxia affected net photosynthesis, irrespective of flow and pH, which suggests that hyperoxia does not induce high rates of photorespiration in this coral. Flow and pH had a synergistic effect on net photosynthesis: at high flow, a decrease in pH stimulated net photosynthesis by 14%. These results indicate that for this individual of G. fascicularis,...
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Although many coral reefs have shifted from coral-to-algal dominance, the consequence of such a transition for coral-algal interactions and their underlying mechanisms remain poorly understood. At the microscale, it is unclear how... more
Although many coral reefs have shifted from coral-to-algal dominance, the consequence of such a transition for coral-algal interactions and their underlying mechanisms remain poorly understood. At the microscale, it is unclear how diffusive boundary layers (DBLs) and surface oxygen concentrations at the coral-algal interface vary with algal competitors and competitiveness. Using field observations and microsensor measurements in a flow chamber, we show that coral (massive Porites) interfaces with thick turf algae, macroalgae, and cyanobacteria, which are successful competitors against coral in the field, are characterized by a thick DBL and hypoxia at night. In contrast, coral interfaces with crustose coralline algae, conspecifics, and thin turf algae, which are poorer competitors, have a thin DBL and low hypoxia at night. Furthermore, DBL thickness and hypoxia at the interface with turf decreased with increasing flow speed, but not when thick turf was upstream. Our results support ...
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Summary Many scleractinian coral species host epizoic acoelomorph flatworms, both in aquaculture and in situ. These symbiotic flatworms may impair coral growth and health through light-shading, mucus removal and disruption of... more
Summary Many scleractinian coral species host epizoic acoelomorph flatworms, both in aquaculture and in situ. These symbiotic flatworms may impair coral growth and health through light-shading, mucus removal and disruption of heterotrophic feeding. To quantify the effect of epizoic flatworms on zooplankton feeding, we conducted video analyses of single polyps of Galaxea fascicularis (Linnaeus 1767) grazing on Artemia nauplii in the presence and absence of symbiotic flatworms. 18S DNA analysis revealed that flatworms inhabiting G. fascicularis belonged to the genus Waminoa (Convolutidae), which were hosted at a density of 3.6±0.4 individuals polyp−1. Polyps hosting flatworms exhibited prey capture rates of 2.2±2.5, 3.4±4.5 and 2.7±3.4 nauplii polyp−1 30 min−1 at prey concentrations of 250, 500 and 1,000 nauplii L−1, respectively. Polyps that had their flatworms removed displayed prey capture rates of 2.7±1.6, 4.8±4.1 and 16.9±10.3 nauplii polyp−1 30 min−1. Significant main and intera...
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Research Interests: Marine Biology, Invertebrates, Marine Aquaculture, Biology, Drug Discovery, and 15 moreAquaculture, Porifera, Medicine, Cnidaria, Marine Natural Products, Pharmaceuticals, Animals, Mollusca, Marine invertebrates, Microorganisms, Microbial Symbionts, Invertebrate, Marine Drugs, Pharmacology and pharmaceutical sciences, and Biological products
Sponge Pump “Darwin's Paradox” asks how productive and diverse ecosystems like coral reefs thrive in the marine equivalent of a desert. De Goeij et al. (p. 108 ) now show that coral reef sponges are part of a highly efficient... more
Sponge Pump “Darwin's Paradox” asks how productive and diverse ecosystems like coral reefs thrive in the marine equivalent of a desert. De Goeij et al. (p. 108 ) now show that coral reef sponges are part of a highly efficient recycling pathway for dissolved organic matter (DOM), converting it, via rapid sponge-cell turnover, into cellular detritus that becomes food for reef consumers. DOM transfer through the sponge loop approaches the gross primary production rates required for the entire coral reef ecosystem.
Research Interests: Science, Biology, Coral Reefs, Medicine, Multidisciplinary, and 8 moreAnthozoa, Animals, Coral Reef, Coral, Sponge, Detritus, Reef, and Microbial Loop
Internal and external feeding on zooplankton may provide scleractinian corals with important nutrients. However, the latter process has never been properly quantified. To quantify the dynamics of zooplankton capture, digestion and release... more
Internal and external feeding on zooplankton may provide scleractinian corals with important nutrients. However, the latter process has never been properly quantified. To quantify the dynamics of zooplankton capture, digestion and release for a scleractinian coral, we performed detailed video analyses of Galaxea fascicularis feeding on Artemia nauplii. A highly dynamic process of prey capture, digestion and release was observed. A single G. fascicularis polyp (N=3) captured 558±67 and released 383±75 Artemia nauplii over a 6 h interval. On average, 98.6% of prey captured was not ingested. Instead, prey items were clustered into aggregates that were digested externally by mesenterial filaments. In addition, we employed carbon, nitrogen and phosphorus analysis of zooplankton before and after digestion by G. fascicularis colonies (N=6). For total organic carbon, 43.1% (0.298±0.148 μg Artemia(-1)) was lost after 6 h of digestion. For total organic nitrogen, total organic phosphorus and ...
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Research Interests: Earth Sciences, Animal Science, Photosynthesis, Biology, Coral Reefs, and 15 moreBiological Sciences, Environmental Sciences, Nutrient Uptake, Respiration, Coral, Metabolic rate, Surface Area, Environmental Conditions, Flow Regime, Growth rate, Flow Rate, Specific Growth Rate, Respiratory Rate, Respiration Rate, and Dry Weight
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In 2009, the European Union funded a collaborative research programme between scientists in the Caribbean, Europe, Australia, and the United States. The project was entitled ‘Future of Reefs in a Changing Environment’ (FORCE) and sought... more
In 2009, the European Union funded a collaborative research programme between scientists in the Caribbean, Europe, Australia, and the United States. The project was entitled ‘Future of Reefs in a Changing Environment’ (FORCE) and sought to help coral reef managers undertake their important work by providing targeted scientific study of the issues, and identify tools and solutions. The research team was broad, with representation across natural and social sciences, a vital combination given that management mostly comprises the modification of peoples’ behaviour and because reefs are important to so many peoples’ livelihood and quality of life. The content and format of this book was developed with the generous input of reef managers througout the region. Our intent was to cover a wide range of critical topics and provide policy and management options throughout. In doing this, we draw on thousands of scientific studies, not just those undertaken by the FORCE project teams. However, where we felt that certain topics had been covered adequately by other resources we opted to point readers towards those resources and only provide a brief summary here.
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In order to improve the methodology for growing and maintaining corals in captivity, a consortium of European zoos, aquaria and academia executed a four-year public/private collaborative research and innovation project (CORALZOO) on the... more
In order to improve the methodology for growing and maintaining corals in captivity, a consortium of European zoos, aquaria and academia executed a four-year public/private collaborative research and innovation project (CORALZOO) on the breeding and husbandry of stony corals. CORALZOO comprised the following topics: (1) sexual and asexual breeding of corals in captivity, including techniques for propagation, feeding and induction of natural coral colony morphogenesis; and (2) coral husbandry: development of generic bioassays to evaluate biotic and abiotic husbandry parameters and to monitor coral health, elaboration of methods for identification and treatment of coral diseases and optimization of transport and acclimation procedures. The results of this project are reviewed.
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Light is one of the most important abiotic factors influencing the (skeletal) growth of scleractinian corals. Light stimulates coral growth by the process of light-enhanced calcification, which is mediated by zooxanthellar photosynthesis.... more
Light is one of the most important abiotic factors influencing the (skeletal) growth of scleractinian corals. Light stimulates coral growth by the process of light-enhanced calcification, which is mediated by zooxanthellar photosynthesis. However, the quantity of light that is available for daily coral growth is not only determined by light intensity (i.e. irradiance), but also by photoperiod (i.e. the light duration time). Understanding and optimizing conditions for coral growth is essential for sustainable coral aquaculture. Therefore, in this study, the question was explored whether more light (i.e. more photons), presented either as irradiance or as light duration, would result in more growth. A series of nine genetically identical coral colonies of Galaxea fascicularis L. were cultured for a period of 18 weeks at different light duration times (8 hours 150 μE m−2 s−1:16 hours dark, 12 hours 150 μE m−2 s−1:12 hours dark, 16 hours 150 μE m−2 s−1:8 hours dark, 24 hours 150 μE m−2 ...
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... 001 grown in the waste water of a sugar refinery 125 Cultivation of marine organisms B. Rinkevich (Israel) Cell cultures ... France) Controlled cultivation of Alexandrium minutum and [33P] orthophosphate cell labeling towards surface... more
... 001 grown in the waste water of a sugar refinery 125 Cultivation of marine organisms B. Rinkevich (Israel) Cell cultures ... France) Controlled cultivation of Alexandrium minutum and [33P] orthophosphate cell labeling towards surface adhesion tests 207 JC Ogbonna, S. Tomiyama ...
Although many coral reefs have shifted from coral-to-algal dominance, the consequence of such a transition for coral –algal interactions and their underlying mechanisms remain poorly understood. At the microscale, it is unclear how... more
Although many coral reefs have shifted from coral-to-algal dominance, the consequence of such a transition for coral –algal interactions and their underlying mechanisms remain poorly understood. At the microscale, it is unclear how diffusive boundary layers (DBLs) and surface oxygen concentrations at the coral –algal interface vary with algal competitors and competitiveness. Using field observations and microsensor measurements in a flow chamber, we show that coral (massive Porites) interfaces with thick turf algae, macro-algae, and cyanobacteria, which are successful competitors against coral in the field, are characterized by a thick DBL and hypoxia at night. In contrast, coral interfaces with crustose coralline algae, conspecifics, and thin turf algae, which are poorer competitors, have a thin DBL and low hypoxia at night. Furthermore, DBL thickness and hypoxia at the interface with turf decreased with increasing flow speed, but not when thick turf was upstream. Our results support the importance of water-mediated transport mechanisms in coral– algal interactions. Shifts towards algal dominance, particularly dense assemblages, may lead to thicker DBLs, higher hypoxia, and higher concentrations of harmful metabolites and pathogens along coral borders, which in turn may facilitate algal overgrowth of live corals. These effects may be mediated by flow speed and orientation.
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Sponges have a remarkable capacity to rapidly regenerate in response to wound infliction. In addition, sponges rapidly renew their filter systems (choanocytes) to maintain a healthy population of cells. This study describes the cell... more
Sponges have a remarkable capacity to rapidly regenerate in response to wound infliction. In addition, sponges rapidly renew their filter systems (choanocytes) to maintain a healthy population of cells. This study describes the cell kinetics of choanocytes in the encrusting reef sponge Halisarca caerulea during early regeneration (0-8 h) following experimental wound infliction. Subsequently, we investigated the spatial relationship between regeneration and cell proliferation over a six-day period directly adjacent to the wound, 1 cm, and 3 cm from the wound. Cell proliferation was determined by the incorporation of 5-bromo-2'-deoxyuridine (BrdU). We demonstrate that during early regeneration, the growth fraction of the choanocytes (i.e., the percentage of proliferative cells) adjacent to the wound is reduced (7.0 ± 2.5%) compared to steady-state, undamaged tissue (46.6 ± 2.6%), while the length of the cell cycle remained short (5.6 ± 3.4 h). The percentage of proliferative choan...
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The world's oceans harbour a large diversity of living organisms. As tropical rainforests have been searched for natural drugs, these marine organisms are being screened for useful products, and a number have been... more
The world's oceans harbour a large diversity of living organisms. As tropical rainforests have been searched for natural drugs, these marine organisms are being screened for useful products, and a number have been found in marine sponges. These are often produced only in trace amounts, and so a large quantity of sponges must be collected to obtain sufficient amounts of