- Amsterdam, Noord-Holland, Netherlands
Marine organism are often kept, cultured, and experimented on in running seawater aquaria. However, surprisingly little attention is given to the nutrient composition of the water flowing through these systems, which is generally assumed... more
Marine organism are often kept, cultured, and experimented on in running seawater aquaria. However, surprisingly little attention is given to the nutrient composition of the water flowing through these systems, which is generally assumed to equal in situ conditions, but may change due to the presence of biofouling organisms. Significantly lower bacterial abundances and higher inorganic nitrogen species (nitrate, nitrite, and ammonium) were measured in aquarium water when biofouling organisms were present within a 7-year old inlet pipe feeding a tropical reef running seawater aquaria system, compared with aquarium water fed by a new, biofouling-free inlet pipe. These water quality changes are indicative of the feeding activity and waste production of the suspension- and filter-feeding communities found in the old pipe, which included sponges, bivalves, barnacles, and ascidians. To illustrate the physiological consequences of these water quality changes on a model organism kept in the...
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The natural beauty of coral reefs attracts millions of tourists worldwide resulting in substantial revenues for the adjoining economies. Although their visual appearance is a pivotal factor attracting humans to coral reefs current... more
The natural beauty of coral reefs attracts millions of tourists worldwide resulting in substantial revenues for the adjoining economies. Although their visual appearance is a pivotal factor attracting humans to coral reefs current monitoring protocols exclusively target biogeochemical parameters, neglecting changes in their aesthetic appearance. Here we introduce a standardized computational approach to assess coral reef environments based on 109 visual features designed to evaluate the aesthetic appearance of art. The main feature groups include color intensity and diversity of the image, relative size, color, and distribution of discernable objects within the image, and texture. Specific coral reef aesthetic values combining all 109 features were calibrated against an established biogeochemical assessment (NCEAS) using machine learning algorithms. These values were generated for ∼2,100 random photographic images collected from 9 coral reef locations exposed to varying levels of an...
Recruitment of the sea urchin Diadema antillarum philippi, 1845 was studied on artificial recruitment panels along the leeward coast of the island of Curaçao, southern Caribbean. Data were compared with historical data from the same coast... more
Recruitment of the sea urchin Diadema antillarum philippi, 1845 was studied on artificial recruitment panels along the leeward coast of the island of Curaçao, southern Caribbean. Data were compared with historical data from the same coast that were collected before (1982-1983) and after (1984) the Caribbean-wide mass mortality of Diadema in October 1983. Average recruitment rates observed in 2005 were
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The composition, ecology and environmental conditions of mesophotic coral ecosystems near the lower limits of their bathymetric distributions remain poorly understood. Here we provide the first in-depth assessment of a lower mesophotic... more
The composition, ecology and environmental conditions of mesophotic coral ecosystems near the lower limits of their bathymetric distributions remain poorly understood. Here we provide the first in-depth assessment of a lower mesophotic coral community (60-100 m) in the Southern Caribbean through visual submersible surveys, genotyping of coral host-endosymbiont assemblages, temperature monitoring and a growth experiment. The lower mesophotic zone harbored a specialized coral community consisting of predominantly Agaricia grahamae, Agaricia undata and a "deep-water" lineage of Madracis pharensis, with large colonies of these species observed close to their lower distribution limit of ~90 m depth. All three species associated with "deep-specialist" photosynthetic endosymbionts (Symbiodinium). Fragments of A. grahamae exhibited growth rates at 60 m similar to those observed for shallow Agaricia colonies (~2-3 cm yr(-1)), but showed bleaching and (partial) mortality w...
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ABSTRACT Algal turf communities are ubiquitous on coral reefs in the Caribbean and are often dominated by N2-fixing cyanobacteria. However, it is largely unknown (1) how much N2 is actually fixed by turf communities and (2) which factors... more
ABSTRACT Algal turf communities are ubiquitous on coral reefs in the Caribbean and are often dominated by N2-fixing cyanobacteria. However, it is largely unknown (1) how much N2 is actually fixed by turf communities and (2) which factors affect their N2 fixation rates. Therefore, we compared N2 fixation activity by turf communities at different depths and during day and night-time on a degraded versus a less degraded coral reef site on the island of Curacao. N2 fixation rates measured with the acetylene reduction assay were slightly higher in shallow (5–10-m depth) than in deep turf communities (30-m depth), and N2 fixation rates during the daytime significantly exceeded those during the night. N2 fixation rates by the turf communities did not differ between the degraded and less degraded reef. Both our study and a literature survey of earlier studies indicated that turf communities tend to have lower N2 fixation rates than cyanobacterial mats. However, at least in our study area, turf communities were more abundant than cyanobacterial mats. Our results therefore suggest that turf communities play an important role in the nitrogen cycle of coral reefs. N2 fixation by turfs may contribute to an undesirable positive feedback that promotes the proliferation of algal turf communities while accelerating coral reef degradation.
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... Article Juvenile Coral Abundance Has Decreased by More Than 50% in Only Three Decades on a Small Caribbean Island Mark JA Vermeij 1,2, *, Judith Bakker 2 , Noam van der Hal 2 and Rolf PM Bak 3 ... pond to bro e 4. Density ent coloure... more
... Article Juvenile Coral Abundance Has Decreased by More Than 50% in Only Three Decades on a Small Caribbean Island Mark JA Vermeij 1,2, *, Judith Bakker 2 , Noam van der Hal 2 and Rolf PM Bak 3 ... pond to bro e 4. Density ent coloure grey). eas the dens in juvenile ...
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Navassa is a small (4.64 km2), uninhabited, oceanic island approximately 50 km off the southwest tip of Haiti (Figure 4.1) under the jurisdiction of the US Fish and Wildlife Service. The island is a raised dolomite plateau ringed by... more
Navassa is a small (4.64 km2), uninhabited, oceanic island approximately 50 km off the southwest tip of Haiti (Figure 4.1) under the jurisdiction of the US Fish and Wildlife Service. The island is a raised dolomite plateau ringed by vertical cliffs that descend to a sloping ...
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Holobionts are species-specific associations between macro- and microorganisms. On coral reefs, the benthic coverage of coral and algal holobionts varies due to natural and anthropogenic forcings. Different benthic macroorganisms are... more
Holobionts are species-specific associations between macro- and microorganisms. On coral reefs, the benthic coverage of coral and algal holobionts varies due to natural and anthropogenic forcings. Different benthic macroorganisms are predicted to have specific microbiomes. In contrast, local environmental factors are predicted to select for specific metabolic pathways in microbes. To reconcile these two predictions, we hypothesized that adaptation of microbiomes to local conditions is facilitated by the horizontal transfer of genes responsible for specific metabolic capabilities. To test this hypothesis, microbial metagenomes were sequenced from 22 coral reefs at 11 Line Islands in the central Pacific that together span a wide range of biogeochemical and anthropogenic influences. Consistent with our hypothesis, the percent cover of major benthic functional groups significantly correlated with particular microbial taxa. Reefs with higher coral cover had a coral microbiome with higher...
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ABSTRACT. Coral mortality has increased in recent decades, making coral recruitment more important than ever in sustaining coral reef ecosystems and contributing to their resilience. This review summarizes existing information on... more
ABSTRACT. Coral mortality has increased in recent decades, making coral recruitment more important than ever in sustaining coral reef ecosystems and contributing to their resilience. This review summarizes existing information on ecological factors affecting scleractinian ...
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Genomics and metagenomics have revolutionized our understanding of marine microbial ecology and the importance of microbes in global geochemical cycles. However, the process of DNA sequencing has always been an abstract extension of the... more
Genomics and metagenomics have revolutionized our understanding of marine microbial ecology and the importance of microbes in global geochemical cycles. However, the process of DNA sequencing has always been an abstract extension of the research expedition, completed once the samples were returned to the laboratory. During the 2013 Southern Line Islands Research Expedition, we started the first effort to bring next generation sequencing to some of the most remote locations on our planet. We successfully sequenced twenty six marine microbial genomes, and two marine microbial metagenomes using the Ion Torrent PGM platform on the Merchant Yacht Hanse Explorer. Onboard sequence assembly, annotation, and analysis enabled us to investigate the role of the microbes in the coral reef ecology of these islands and atolls. This analysis identified phosphonate as an important phosphorous source for microbes growing in the Line Islands and reinforced the importance of L-serine in marine microbia...
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Research Interests: Morphogenesis, Quantitative analysis, Biological Sciences, Software, Computer Simulation, and 12 moreAnthozoa, Computer Model, Animals, Caribbean region, Experimental Study, Morphological Variation, Three Dimensional, Quantitative Analysis, Light Availability, Species Specificity, X ray Computed Tomography, and Simulation Model
Research Interests: Carbon, Diet, Porifera, Multidisciplinary, Anthozoa, and 4 moreAnimals, Bacteria, PLoS one, and Organic Chemicals
The use of molecular data for species delimitation in Anthozoa is still a very delicate issue. This is probably due to the low genetic variation found among the molecular markers (primarily mitochondrial) commonly used for Anthozoa.... more
The use of molecular data for species delimitation in Anthozoa is still a very delicate issue. This is probably due to the low genetic variation found among the molecular markers (primarily mitochondrial) commonly used for Anthozoa. Ceriantharia is an anthozoan group that has not been tested for genetic divergence at the species level. Recently, all three Atlantic species described for the genus Isarachnanthus of Atlantic Ocean, were deemed synonyms based on morphological simmilarities of only one species: Isarachnanthus maderensis. Here, we aimed to verify whether genetic relationships (using COI, 16S, ITS1 and ITS2 molecular markers) confirmed morphological affinities among members of Isarachnanthus from different regions across the Atlantic Ocean. Results from four DNA markers were completely congruent and revealed that two different species exist in the Atlantic Ocean. The low identification success and substantial overlap between intra and interspecific COI distances render the Anthozoa unsuitable for DNA barcoding, which is not true for Ceriantharia. In addition, genetic divergence within and between Ceriantharia species is more similar to that found in Medusozoa (Hydrozoa and Scyphozoa) than Anthozoa and Porifera that have divergence rates similar to typical metazoans. The two genetic species could also be separated based on micromorphological characteristics of their cnidomes. Using a specimen of Isarachnanthus bandanensis from Pacific Ocean as an outgroup, it was possible to estimate the minimum date of divergence between the clades. The cladogenesis event that formed the species of the Atlantic Ocean is estimated to have occured around 8.5 million years ago (Miocene) and several possible speciation scenarios are discussed.
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... disturbed reefs, certain species had disappeared from the community, showed a different population structure (eg Colpophyllia natans and Diploria ... life-history strategies associated with each reproduc-tive mode (Szmant 1986,... more
... disturbed reefs, certain species had disappeared from the community, showed a different population structure (eg Colpophyllia natans and Diploria ... life-history strategies associated with each reproduc-tive mode (Szmant 1986, Harrison & Wallace 1990, Hughes & Connell 1999 ...
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The Janzen-Connell hypothesis states that host-specific biotic enemies (pathogens and predators) promote the coexistence of tree species in tropical forests by causing distance- or density-dependent mortality of seeds and seedlings.... more
The Janzen-Connell hypothesis states that host-specific biotic enemies (pathogens and predators) promote the coexistence of tree species in tropical forests by causing distance- or density-dependent mortality of seeds and seedlings. Although coral reefs are the aquatic analogues of tropical forests, the Janzen-Connell model has never been proposed as an explanation for high diversity in these ecosystems. We tested the central predictions of the Janzen-Connell model in a coral reef, using swimming larvae and settled polyps of the common Caribbean coral Montastraea faveolata. In a field experiment to test for distance- or density-dependent mortality, coral settler mortality was higher and more strongly density dependent in locations down-current from adult corals. Survival did not increase monotoilically with distance, however, revealing the influence of fluid dynamics around adult corals in structuring spatial patterns of mortality. Complementary microbial profiles around adult coral heads revealed that one potential cause of settler mortality, marine microbial communities, are structured at the same spatial scale. In a field experiment to test whether factors causing juvenile mortality are host specific, settler mortality was 2.3-3.0 times higher near conspecific adults vs. near adult corals of other genera or in open reef areas. In four laboratory experiments to test for distance-dependent, host-specific mortality, swimming coral larvae were exposed to water collected near conspecific adult corals, near other coral genera, and in open areas of the reef. Microbial abundance in these water samples was manipulated with filters and antibiotics to test whether the cause of mortality was biotic (i.e., microbial). Juvenile survivorship was lowest in unfiltered water collected near conspecifics, and survivorship increased when this water was filter sterilized, collected farther away, or collected near other adult coral genera. Together these results demonstrate for the first time that the diversity-promoting mechanisms embodied in the Janzen-Connell model can operate in a marine ecosystem and in an animal. The distribution of adult corals across a reef will thus influence the spatial pattern of juvenile survival. When rare coral species have a survival advantage, coral species diversity per se becomes increasingly important for the persistence and recovery of coral cover on tropical reefs.
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Reproductive patterns were studied in closely related coral species of the genus Madracis on Curaçao, Netherlands Antilles. Gonadal development of six sympatric species was examined over a 13-month period. Reproductive differences among... more
Reproductive patterns were studied in closely related coral species of the genus Madracis on Curaçao, Netherlands Antilles. Gonadal development of six sympatric species was examined over a 13-month period. Reproductive differences among Madracis species are small. All species are hermaphroditic brooders and show similar patterns in gamete development. Timing of gamete maturation is positively correlated with seawater temperature in all
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(Phacelocyanthus flos, Caryophyllidae) consists of integrated clusters of small (0.5–1.5 cm) corallites whose skeleton is connected by a common base (Figs. 1 and 2). This species lives attached to and encrusts the underside of overhangs,... more
(Phacelocyanthus flos, Caryophyllidae) consists of integrated clusters of small (0.5–1.5 cm) corallites whose skeleton is connected by a common base (Figs. 1 and 2). This species lives attached to and encrusts the underside of overhangs, cave ceilings, and hard structures at depths from 20–355 m (Cairns 1979).
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The development of a coral community was monitored for 6 years (1998–2004) on 46 m2 of artificial settlement substrate in Curaçao, Netherlands Antilles. Growth and survival of recruits (n=1385) belonging to 16 different species were... more
The development of a coral community was monitored for 6 years (1998–2004) on 46 m2 of artificial settlement substrate in Curaçao, Netherlands Antilles. Growth and survival of recruits (n=1385) belonging to 16 different species were quantified in relation to characteristics of the benthic community developing around them. The early life history dynamics (i.e. growth rate, growth strategy and survival) of corals differed
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Recruitment of the sea urchin Diadema antillarum philippi, 1845 was studied on artificial recruitment panels along the leeward coast of the island of Curaçao, southern Caribbean. Data were compared with historical data from the same coast... more
Recruitment of the sea urchin Diadema antillarum philippi, 1845 was studied on artificial recruitment panels along the leeward coast of the island of Curaçao, southern Caribbean. Data were compared with historical data from the same coast that were collected before (1982-1983) and after (1984) the Caribbean-wide mass mortality of Diadema in October 1983. Average recruitment rates observed in 2005 were equal to 2.2 times lower compared to those observed before the D. antillarum die-off (1982 and 1983), but 56.5 times higher than those observed after the die-off in 1984. The increase in recruitment rates between 1984 and 2005 was 5-51 times greater than the increase in abundance of adult individuals over the same period. This suggests that despite the largely recovered recruitment rates of this important reef herbivore, unknown sources of high post-settlement mortality currently prevent a similar recovery of its adult population.
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Research Interests: Engineering, Physics, Chemistry, Biology, Coral Reefs, and 16 moreSound, Marine Larval Biology & Ecology, Marine Embryos and Larvae, Medicine, Multidisciplinary, Anthozoa, Movement, Animals, Life Cycle, PLoS one, Noise Pollution, Larval Behavior, Caribbean Corals, Marine Environment, Larva, and Reef Fish
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Research Interests: Computed Tomography, Carbon, Regional development, Morphogenesis, Biological Sciences, and 12 moreglobal Climate change, 3-D Imaging, Anthozoa, Diffusion, Animals, Three Dimensional, Simulation Study, Simulation experiment, X ray Computed Tomography, Dissolved Inorganic Carbon, Marine ecosystem, and Oxygen Consumption
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Much of coral reef ecology has focused on how human impacts change coral reefs to macroalgal reefs. However, macroalgae may not always be a good indicator of reef decline, especially on reefs with significant sea urchin populations, as... more
Much of coral reef ecology has focused on how human impacts change coral reefs to macroalgal reefs. However, macroalgae may not always be a good indicator of reef decline, especially on reefs with significant sea urchin populations, as found in Kenya and Hawaii. This study tests the effects of trophic interactions (i.e. herbivory by fishes and sea urchins) and spatial competition (between algae and coral) on algal community structure of reefs surrounding two Hawaiian Islands that vary in their level of human impacts. Reef-building organisms (corals and crustose coralline algae) were less abundant and turf algae were more abundant on Maui as compared to Lanai, where human impacts are lower. In contrast to previous studies, we found no evidence that macroalgae increased with human impacts. Instead, low turf and macroalgal abundance were best explained by the interactive effects of coral cover and sea urchin abundance. Fishing sea urchin predators appeared to have cascading effects on the benthic community. The absence of sea urchin predators and high sea urchin densities correspond to a disproportionately high abundance of turf and crustose coralline algae. We propose that high turf algal abundance is a better indicator of reef decline in Hawaii than high macroalgal abundance because turf abundance was highest on reefs with low coral cover and few fish. The results of this study emphasize that understanding changes in community composition are context-dependent and that not all degraded reefs look the same.
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Restoration of degraded coral reef communities is dependent on successful recruitment and survival of new coral planulae. Degraded reefs are often characterized by high cover of fleshy algae and high microbial densities, complemented by... more
Restoration of degraded coral reef communities is dependent on successful recruitment and survival of new coral planulae. Degraded reefs are often characterized by high cover of fleshy algae and high microbial densities, complemented by low abundance of coral and coral recruits. Here, we investigated how the presence and abundance of macroalgae and microbes affected recruitment success of a common Hawaiian coral. We found that the presence of algae reduced survivorship and settlement success of planulae. With the addition of the broad-spectrum antibiotic, ampicillin, these negative effects were reversed, suggesting that algae indirectly cause planular mortality by enhancing microbial concentrations or by weakening the coral’s resistance to microbial infections. Algae further reduced recruitment success of corals as planulae preferentially settled on algal surfaces, but later suffered 100% mortality. In contrast to survival, settlement was unsuccessful in treatments containing antibiotics, suggesting that benthic microbes may be necessary to induce settlement. These experiments highlight potential complex interactions that govern the relationships between microbes, algae and corals and emphasize the importance of microbial dynamics in coral reef ecology and restoration.
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The effect of herbivory and nutrient enrichment on the growth of invasive and native macroalgal species was simultaneously studied in two biogeographic regions: the Caribbean and Hawaii. Herbivores suppressed growth of invasive algae in... more
The effect of herbivory and nutrient enrichment on the growth of invasive and native macroalgal species was simultaneously studied in two biogeographic regions: the Caribbean and Hawaii. Herbivores suppressed growth of invasive algae in their native (Caribbean) and invaded range (Hawaii), but despite similar levels of herbivore biomass, the intensity of herbivory was lower in Hawaii. Algal species with a circumtropical distribution did not show a similar effect of herbivores on their growth. Nutrient enrichment did not enhance growth of any algal species in either region. The reduction in herbivore intensity experienced by invasive algae in Hawaii rather than an escape from (native) herbivores provided invasive macroalgae with “enemy release” sensu the Enemy Release Hypothesis (ERH). Since native, Hawaiian herbivores still feed and even prefer invasive algae over native species, invasion scenario’s that involve predation (e.g. the ERH) could be falsely dismissed when invasive species are only studied in their invasive range. We therefore argue that escape from herbivores (i.e. enemy release) can only effectively be determined with additional information on the intensity of predation experienced by an invasive species in its native range.
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Patterns of fluorescence and colony tissue, colour were studied (field observations and epifluorescence microscopy) in six species of the coral genus Madracis over depth from 10 to 60 m at a reef slope in Curaçao. Two functions showed up:... more
Patterns of fluorescence and colony tissue, colour were studied (field observations and epifluorescence microscopy) in six species of the coral genus Madracis over depth from 10 to 60 m at a reef slope in Curaçao. Two functions showed up: (1) Decrease in number of colourmorphs (n = 25) with depth suggests a photo-protective function where short wavelengths (e.g. UV) are transformed to long wavelengths, (2) Green fluorescence, observed in four species over their entire depth range, transforms radiation to wavelengths useful for photosynthesis. The observed patterns in fluorescence between species did not correspond to the current taxonomic classification. Our results do not support the usefulness of fluorescence as a taxonomic tool in corals.
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Research Interests: Geography, Technology, Microbial Ecology, Coral Reefs, Ecophysiology, and 26 moreMetagenomics, Environmental Biotechnology, Biological Sciences, Environmental Sciences, Anthozoa, Microbes, Animals, Archaea, Ecosystems, Bacteria, Coral Reef, Iron, Seawater, Seaweed, Microorganisms, Rhodophyta, Ships, Microbial Activity, Pacific ocean, Genomic Library, Calcium Carbonate, Virulence Factors, Benthic Communities, Phase Shift, Microbial community, and Phase Shifter
Research Interests: Engineering, Physics, Chemistry, Biology, Coral Reefs, and 16 moreSound, Marine Larval Biology & Ecology, Marine Embryos and Larvae, Medicine, Multidisciplinary, Anthozoa, Movement, Animals, Life Cycle, PLoS one, Noise Pollution, Larval Behavior, Caribbean Corals, Marine Environment, Larva, and Reef Fish
We investigate the relationship between habitat heterogeneity and morphological variation in the Caribbean coral species-complex, Madracis pharensis/decactis. This complex showed strong but incomplete morphospecies habitat-matching on a... more
We investigate the relationship between habitat heterogeneity and morphological variation in the Caribbean coral species-complex, Madracis pharensis/decactis. This complex showed strong but incomplete morphospecies habitat-matching on a small spatial scale. We find that only one Madracis morphospecies dominates in environments consisting of either few vertical or few horizontal habitats, whereas in environments consisting of a mixture of horizontal and vertical habitats both morphospecies are common. We demonstrate that the observed patterns of morphospecies habitat-matching cannot be explained by a pure polyphenic model, where morphological variants are induced by a genotype-by-environment interaction at their settling site. Instead, we suggest that habitat-matching results in whole or in part from genetically predetermined factors. We present support for the hypothesis that this pattern of habitat-matching is due to habitat- and morphospecies-specific selective factors. Our study describes how a variable environmental factor, i.e. habitat distribution, has a non-linear effect on the spatial distribution of these morphospecies, thereby influencing the genetic organization of the Madracis coral complex at the ~+1–10 km spatial scale.