Ronald Osinga

Ronald Osinga
Wageningen University & Research | WUR · Department of Aquaculture and Fisheries

Doctor of Philosophy

About

131
Publications
51,484
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3,625
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Publications

Publications (131)
Article
Full-text available
The massive die-off of the sea urchin Diadema antillarum in 1983–1984 is one the main reasons for low coral recruitment and little coral recovery in the Caribbean. As the natural recovery of D. antillarum is slow to non-existent, multiple restoration studies have been attempted. There are currently three different approaches to obtain individuals f...
Preprint
The increase of macroalgae at degraded reefs impedes ecosystem services and calls for effective methods to facilitate a return to coral dominance. Removal of macroalgae (i.e. browsing) is typically realized by fish, but the role and identity of browsers at the heavily-fished East African Coast is still largely unknown. This study investigated how b...
Article
Full-text available
To support the use of marine demosponges for collagen production in integrated culture settings, we investigated a low–cost, easily applicable and sustainable production method for the culture of Chondrosia reniformis Nardo, 1847 (Demospongiae, Chondrosiida, Chondrosiidae). Novel methods were tested to culture this collagen-rich demosponge in three...
Article
Full-text available
p>Caribbean coral reefs are in decline and the deployment of artificial reefs, structures on the sea bottom that mimic one or more characteristics of a natural reef, is increasingly often considered to sustain ecosystem services. Independent of their specific purposes, it is essential that artificial reefs do not negatively affect the already stres...
Article
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Plumes of re-suspended sediment potentially smother and clog the aquiferous system of filter-feeding sponges with unknown implications for their health. For the first time, we examined the physiological responses of repeated exposure to natural sediment in the glass sponge Vazella pourtalesii, which forms dense sponge grounds in Emerald Basin off N...
Article
Ocean warming has severe impacts on coral reef ecosystems with frequent incidences of coral bleaching. In addition, eutrophication poses an increasing threat to coral reef environments and has been found to increase the vulnerability of corals to thermal bleaching. Eutrophication has accelerated in recent years with coastal nutrient loads expected...
Article
Full-text available
Sponges are ubiquitous components of various deep-sea habitats, including cold water coral reefs, and form deep-sea sponge grounds. Although the deep sea is generally considered to be a food-limited environment, these ecosystems are known to be hotspots of biodiversity and carbon cycling. To assess the role of sponges in the carbon cycling of deep-...
Article
Full-text available
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 c...
Preprint
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...
Article
Full-text available
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 tr...
Article
Full-text available
In this study, we compared the early fish colonization of three types of artificial reefs deployed in the coastal waters of Saba and St Eustatius in the Caribbean: reef balls®, layered cakes and piles of locally obtained basaltic rock. As an indicator of performance, three fish assemblage parameters (abundance, biomass, species richness) were measu...
Article
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Coral bleaching due to global warming currently is the largest threat to coral reefs, which may be exacerbated by altered water quality. Elevated levels of the UV filter oxybenzone in coastal waters as a result of sunscreen use have recently been demonstrated. We studied the effect of chronic oxybenzone exposure and elevated water temperature on co...
Preprint
Full-text available
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...
Preprint
Full-text available
We studied the effect of chronic oxybenzone exposure and elevated temperature on coral health. Microcolonies of Stylophora pistillata and Acropora tenuis were cultured in 20 flow-through aquaria, of which 10 were exposed to oxybenzone at a field-relevant concentration of ~0.06 μg L ⁻¹ at 26 °C. After two weeks, half of the corals experienced a heat...
Poster
Full-text available
Poster presentation on herbivory and corallivory on coral nurseries, at WIOMSA 2019
Article
Coral mariculture involves time-consuming removal of fouling. On natural reefs, this service is provided by grazers. As natural reefs also harbour corallivores, it is debated whether reef-bound fish have a positive or negative effect on coral maricultured near natural reefs. This study quantified the net impact of herbivorous and corallivorous fish...
Article
Full-text available
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, plat...
Article
Full-text available
Recent research suggests that prior exposure of several months to elevated irradiance induces enhanced thermal tolerance in scleractinian corals. While this tolerance has been reported at the species level, individual coral colonies may react differently due to individual variability in thermal tolerance. As thermal anomalies are predicted to becom...
Data
Figure S1: Image of light spectrum. Spectrum of Orphek PR-156W.
Data
Table S2: Table displaying significant main effects and interactions (excluding colony). Summary of significant main effects and interactions based on factorial analysis of variance for photographic analyses and fluorescence (EQY).
Data
Figure S2: Image of each group of ramets after fragging and during heat stress. Photographs of Stylophora pistillata ramet (one ramet per group) after fragging, and during heat stress (day 44, 51 and 57). Control treatment (CT). Experimental treatment (ET). Colony 1 (C1), Colony 2 (C2) and Colony 3 (C3).
Data
Figure S3: Image of DGGE gel (Symbiodinium ITS2). DGGE gel displaying Symbiodinium community based on ITS2.
Data
Table S1: Table displaying significant main effects and interactions (including colony). Summary of significant main effects and interactions based on factorial analysis of variance for specific growth rate (during light treatment), cell density, chlorophyll a and photographic analyses, linear mixed model for fluorescence (EQY) and permutational mu...
Article
Full-text available
In 2010, Dutch dredging and marine contractor, Van Oord, launched a Coral Rehabilitation Initiative as part of its Sustainability and Marine Ingenuity agenda. The key challenge was to demonstrate that already proven small-scale coral breeding techniques can be scaled-up and applied in practice to promote environmental gain around marine infrastruct...
Article
Full-text available
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) vers...
Preprint
Full-text available
Zinc levels in artificial seawater are often unnaturally elevated, and thus potentially toxic to aquacultured corals. However, our knowledge of how zinc affects corals is still limited. We tested the effects of zinc supplementation (0, 1, 10 and 100 µg L –1 ) on health, growth, NDVI (a proxy for chlorophyll a ) and overall colouration of the stony...
Preprint
Full-text available
Zinc levels in artificial seawater are often unnaturally elevated, and thus potentially toxic to aquacultured corals. However, our knowledge of how zinc affects corals is still limited. We tested the effects of zinc supplementation (0, 1, 10 and 100 µg L –1 ) on health, growth, NDVI (a proxy for chlorophyll a ) and overall colouration of the stony...
Chapter
Full-text available
Coral reef degradation worldwide and the concomitant increasing demand for corals to supply the marine ornamental trade have been driving the growing interest for coral aquaculture. Captive breeding and propagation of corals among aquarium hobbyists and public aquariums is a well-known and established activity. In contrast, the scientific community...
Article
Full-text available
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 competi...
Article
Full-text available
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...
Article
Full-text available
This study describes in vivo cell turnover (the balance between cell proliferation and cell loss) in eight marine sponge species from tropical coral reef, mangrove and temperate Mediterranean reef ecosystems. Cell proliferation was determined through the incorporation of 5-bromo-2'-deoxyuridine (BrdU) and measuring the percentage of BrdU-positive c...
Article
Full-text available
Coral aquaculture is an activity of growing interest due to the degradation of coral reefs worldwide and concomitant growing demand for corals by three industries: marine ornamental trade, pharmaceutical industry and reef restoration. Although captive breeding and propagation of corals is a well-known activity among aquarium hobbyists and public aq...
Article
Full-text available
The chemical diversity associated with marine natural products (MNP) is unanimously acknowledged as the “blue gold” in the urgent quest for new drugs. Consequently, a significant increase in the discovery of MNP published in the literature has been observed in the past decades, particularly from marine invertebrates. However, it remains unclear whe...
Article
Full-text available
Coral reefs are essential to many nations, and are currently in global decline. Although climate models predict decreases in seawater pH (∼0.3 units) and oxygen saturation (∼5 percentage points), these are exceeded by the current daily pH and oxygen fluctuations on many reefs (pH 7.8-8.7 and 27-241% O2 saturation). We investigated the effect of oxy...
Article
Full-text available
Light spectrum plays a key role in the biology of symbiotic corals, with blue light resulting in higher coral growth, zooxanthellae density, chlorophyll a content and photosynthesis rates as compared to red light. However, it is still unclear whether these physiological processes are blue-enhanced or red-repressed. This study investigated the indiv...
Data
Coral reefs are essential to many nations, and are currently in global decline. Although climate models predict decreases in seawater pH (0.3 units) and oxygen saturation (5 percentage points), these are exceeded by the current daily pH and oxygen fluctuations on many reefs (pH 7.8-8.7 and 27-241% O2 saturation). We investigated the effect of oxyge...
Article
Full-text available
Ever since Darwin's early descriptions of coral reefs, scientists have debated how one of the world's most productive and diverse ecosystems can thrive in the marine equivalent of a desert. It is an enigma how the flux of dissolved organic matter (DOM), the largest resource produced on reefs, is transferred to higher trophic levels. Here we show th...
Article
Corals are an important source of bioactive metabolites.Coral aquaculture for metabolite production is economically viable. Marine natural products (NP) are unanimously acknowledged as the �blue gold� in the urgent quest for new pharmaceuticals. Although corals are among the marine organisms with the greatest diversity of secondary metabolites, gro...
Article
Full-text available
The process of biofouling of marine structures and substrates, such as platforms or ship hulls, proceeds in multiple steps. Soon after the formation of an initial conditioning film, formed via the adsorption of organic particles to natural or man-made substrates, a population of different bacterial taxa associates under the formation of a biofilm....
Article
Full-text available
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 pol...
Article
Full-text available
Heterotrophy is known to stimulate calcification of scleractinian corals, possibly through enhanced organic matrix synthesis and photosynthesis, and increased supply of metabolic DIC. In contrast to the positive long-term effects of heterotrophy, inhibition of calcification has been observed during feeding, which may be explained by a temporal oxyg...
Article
Full-text available
Several factors may affect heterotrophic feeding of benthic marine invertebrates, including water flow rate and polyp context (i.e., the presence of neighbouring polyps). We tested the interactive effects of water flow rate and polyp context on zooplankton feeding by the scleractinian coral Galaxea fascicularis. Single polyps and colonies were incu...
Article
Full-text available
Marine sponges are a rich source of bioactive compounds with pharmaceutical potential. Since biological production is one option to supply materials for early drug development, the main challenge is to establish generic techniques for small-scale production of marine organisms. We analysed the state of the art for cultivation of whole sponges, spon...
Article
Full-text available
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 intensi...
Article
Full-text available
In order to determine optimal feeding regimes for captive corals, prey capture by the scleractinian coral Galaxea fascicularis was determined by measuring clearance of prey items from the surrounding water. Colonies of G. fascicularis (sized between 200 and 400 polyps) were incubated in 1300 ml incubation chambers. Nauplii of the brine shrimp Artem...
Article
Full-text available
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...
Article
Due to global degradation of coral reefs and high demand for scleractinian corals, aquaculture of these marine organisms is gaining importance. To make coral aquaculture economically viable, optimisation of culture protocols is vital. We determined the effects of irradiance and light spectrum on the growth of a model scleractinian coral species, Ga...