Bonaire

Potential and limits of combining studies of coarse- and fine-grained sediments for the coastal event history of a Caribbean carbonate environment

The coastal deposits of Bonaire, Leeward Antilles, are among the most studied archives for extreme-wave events (EWEs) in the Caribbean. Here we present more than 400 electron spin resonance (ESR) and radiocarbon data on coarse-clast deposits from Bonaire’s eastern and western coasts. The chronological data are compared to the occurrence and age of fine-grained extremewave deposits detected in lagoons and floodplains. Both approaches are aimed at the identification of EWEs, the differentiation between extraordinary storms and tsunamis, improving reconstructions of the coastal evolution, and establishing a geochronological framework for the events. Although the combination of different methods and archives contributes to a better understanding of the interplay of coastal and archive-related processes, insufficient separation, superimposition or burying of coarse-clast deposits and restricted dating accuracy limit the use of both fine grained and coarse-clast geoarchives to unravel decadal- to centennial-scale events. At several locations, distinct landforms are attributed to different coastal flooding events interpreted to be of tsunamigenic origin. Coastal landforms on the western coast have significantly been influenced by (sub)-recent hurricanes, indicating that formation of the coarse-clast deposits on the eastern coast is likely to be related to past events of higher energy.

 

Date
2013
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Bonaire

What's Bonaire's nature worth? 2011-2012

This Initiative draws attention to the economic benefits of biodiversity and highlights the growing costs of biodiversity loss and ecosystem degradation. Insight in the value of ecosystems and biodiversity can support decision makers to make wise and inclusive decisions for long-term sustainable economic development.

Information on the Total Economic Value (TEV) of Bonaire’s nature is used to build a strategy to advocate for the effective conservation measures on Bonaire. The TEV is the sum of the ecosystem services provided by the marine and terrestrial ecosystems of Bonaire. In total, more than 10 different services have been valued on monetary terms. The most relevant services that were estimated in extensive sub-studies include the following:

  • Local cultural and recreational values
  • International tourism value 
  • Fisheries values 
  • Non-use value 
  • Coastal protection value 
  • Functional Valuation of Ecosystem Services on Bonaire 

Through the use of simulation models, scenario development and cost & benefit analysis the efficacy of various interventions is determined. Cost-benefit analysis of different scenarios provides an objective means of deciding which interventions produces the highest yield. Such an integral approach ultimately ensures the betterment of Bonaire’s environment while at the same time warranting sustainable economic development.

Date
2013
Data type
Media
Theme
Research and monitoring
Geographic location
Bonaire

Ecological values of the 12 miles zone of Bonaire

In 2015 an Expert group assessed the ten Dutch World Heritage candidate sites and advised the Ministry of Education, Culture and Science with regards to the potential nomination of Bonaire National Marine Park. The conclusion was that further research is needed to demonstrate its Outstanding Universal Value (OUV). According to the Expert group, the current size and boundaries of BNMP do not contain features which qualify the property as unique, hence extension of the BNMP boundaries was recommended. Possibilities for extension are the island Curaçao, the islands off the coast of Venezuela and the 12 miles zone.

In collaboration with the Ministry of Economic Affairs it was decided to start by studying the nature values of the 12 miles zone of Bonaire, because this is the most feasible boundary extension. The 12 miles zone of Bonaire has a total area of almost 360,000 ha, which is a 74-fold enlargement compared to the 4,860 ha of the current boundaries of BNMP.

The objective was to determine the existence of potential nature values per zone based on the following criteria: rare, threatened or characteristic species; rare, untouched or undisturbed geomorphological features; important physical oceanographic features; potential ecosystem services. An inventory of previous studies by IMARES and available data from two deep sea expeditions in 2000 and 2013 were incorporated in this study.

Our review updates the current state of knowledge on the deep sea of the Caribbean Sea, focussing on the 12 miles zone of Bonaire. It provides a general framework for the decision making process on the boundary extension of the potential World Heritage Site and how to strengthen the potential OUV.

The available information shows that the 12 miles zone contains some attributes that will strengthen the OUV to some extent, such as the discovery of 16 species new to science at the deeper reef of Bonaire and the presence of some species endemic to the Southern Caribbean Ecoregion. Convincing documentation is still lacking, however evidence from past deep sea expeditions indicates that further studies of deep water biodiversity will likely easily yield a wealth of new species. Also potential offshore sea mounts within the 12 miles zone of Bonaire may be worthwhile investigating, by mapping the seafloor through a bathymetric survey. These potential habitats, structures and new species in the 12 miles zone of Bonaire could greatly add to the OUV of the BNMP.

Date
2016
Data type
Research report
Theme
Research and monitoring
Report number
C026/16
Geographic location
Bonaire

Negative effects of gardening damselfish Stegastes planifrons on coral health depend on predator abundance

On Bonaire, we studied the effects of predator abundance and habitat availability on the abundance of the threespot damselfish Stegastes planifrons, a species that creates algal gardens at the expense of live coral cover. Across 21 sites, predator biomass ranged from 12 to 193 g m−2 (mean = 55.1; SD = 49.1) and benthic cover of S. planifrons’ preferred habitat (corals of the Orbicella species complex) ranged from 2.2 to 38.0% (mean = 14.3; SD = 9.6). Across these gradients, the local abundance of S. planifrons was significantly and negatively related to preda- tor biomass, but not to habitat availability. Increased local abundance of S. planifrons corre- sponded to an increasingly larger proportion of coral colonies affected by its ‘farming behavior’, resulting in an increased prevalence of coral disease. Thus, predators indirectly affected the com- position of reef communities around Bonaire by controlling damselfish abundance. Furthermore, the abundance of S. planifrons could not be correlated with its preferred habitat, despite such cor- relations having been observed elsewhere in the Caribbean. 

Date
2015
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Bonaire

‘Quick scan’ to assess the prevalence of dermal parasites among coral reef fishes of Bonaire.

In the past, diseases and infections have had dramatic impacts on Caribbean coral reef ecosystems (e.g. white band disease in corals (Pantos and Bythell, 2006); mass mortality of the sea urchin Diadema (Lessions, 2005)). Regular monitoring of reef organisms for signs of disease and infections may be important as an “early warning system” to possibly prevent devastating outbreaks. 
In September 2013 an unusual number of reef fish species (e.g. Scaridae (Fig. 1.1 , Acanthuridae and Pomacanthidae) infected with dermal parasites were observed during a dive at Salt Pier (M. de Graaf, pers. obs.). In September 2014 one princess parrotfish infected with dermal parasites was dissected and internal and external samples were send to the Central Veterinairy Institute (CVO) in Lelystad (Netherlands) for further histopathological examination. According to CVO the parrotfish suffered from a microspore parasitic infection of the skin, muscles and digestive tract. The cysts caused fibrotic abscesses and necrosis on the fins.

Similar dermal parasites were observed in a recent survey of coral reef fishes on Curaçao and the observed external blemishes were associated with infections by trematodes (digenean metacercaria), turbellarians and protozoans (Cryptocaryon) (Bernal et al., 2015). Bernal et al. (2015) reported that infection rates of coral reef fish on Curacao were almost ten times higher compared to infection rates of coral reef fish surveyed in Mexico and Belize. To date, only anecdotal observations exist of parasite infections on coral reef fish on Bonaire but no quantitative assessment of the prevalence of dermal parasites is available. 
The objective of the Helpdeskvraag was to:
1) conduct a “quick scan” to determine the current prevalence of dermal parasites among the coral reef fish of Bonaire, and

2) advise EZ on possible consequences and future actions depending on the outcome of the “quick scan”. 

 

Date
2015
Data type
Research report
Theme
Research and monitoring
Report number
C055/15
Geographic location
Bonaire
Image

Fisher and diver perceptions of coral reef degradation and implications for sustainable management

Fishers and divers are the major resource users of Caribbean coral reefs. On Curaçao and Bonaire, reef condition is good relative to the Caribbean average, but fishes and corals have greatly declined over the last few decades. We interviewed 177 fishers and 211 professional SCUBA divers to assess their views on the extent and causes of degradation. Fishers know fish stocks are severely depleted and declining, whereas divers were aware of declines but had “shifted baselines” and consider the reefs healthy. Fishers and divers differ in perceptions of the causes and appropriate remedies for decline. Fishers generally blame external factors such as changes in climate, currents, or industrial fishing offshore, whereas divers primarily blame overfishing and coastal development. Nevertheless, the great majority of both fishers and divers support more management of both fishing and diving. Thus the social climate is ripe for balanced and strong restrictions on both groups for reef recovery and sustainable use. Exclusion of both fishers and divers from protected areas of significant size around the islands would be a major step forward towards the long-term conservation of reef resources.

Date
2015
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Bonaire
Curacao

Bonaire National Marine Park—Algal Survey and Inventory

The Littler’s team [including Barrett Brooks, Don Hurlbert, Barbara Watanabe and Larry Gorenflo (Conservation International)] traveled to the island of Bonaire, Netherlands Antilles (1 Nov 06 to 14 Nov 06). The purpose of this expedition was to assist the Ministry of Nature Affairs for the Netherlands Antilles (MINA) and the Center for Applied Biodiversity Science at Conservation International to assess the current status of Bonaire’s marine flora. The team collected over 300 specimens from the upper reef to a depth of 56 m. This assessment increased the known species reported from Bonaire by 35% (Appendix II, List of Species). The marine flora is typical of many Caribbean reefs with no specific areas of extremely high diversity or unique species composition. Also included in this evaluation are over 100 digital images (Appendix III), properly identified to the species level in most cases. These images may be used by managers in web sites, oral presentation, training manuals, brouchures, etc., to make marine plant identification possible for Bonaire’s many divers, volunteers, conservationists or interested agencies.
The team surveyed the health of the reefs using key indicator species (recognized from our >30 continuous years of coral-reef research) in reference to the growing problems associated with eutrophication and overfishing along tropical and subtropical shorelines worldwide. The ecological responses of corals and macroalgae to nutrient enrichment and release from predation have been repeatedly cited as priority areas in need of further research (National Research Council, 2000; Littler & Littler 2006).

Date
2006
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire

Deep-water sponges (Porifera) from Bonaire and Klein Curaçao, Southern Caribbean

Four submersible dives off the coast of Bonaire (Caribbean Netherlands) and Klein Curaçao (Curaçao) to depths of 99.5–242 m, covering lower mesophotic and upper dysphotic zones, yielded 52 sponge specimens belonging to 31 species. Among these we identified 13 species as new to science. These are Plakinastrella stinapa n. sp., Pachastrella pacoi n. sp., Characella pachastrelloides n. sp., Geodia curacaoensis n. sp., Caminus carmabi n. sp., Discodermia adhaerens n. sp., Clathria (Microciona) acarnoides n. sp., Antho (Acarnia) pellita n. sp., Parahigginsia strongylifera n. sp., Calyx magnoculata n. sp., Neopetrosia dutchi n. sp., Neopetrosia ovata n. sp. and Neopetrosia eurystomata n. sp. We also report an euretid hexactinellid, which belongs to the rare genus Verrucocoeloidea, recently described (2014) as V. liberatorii Reiswig & Dohrmann. The remaining 18 already known species are all illustrated by photos of the habit, either in situ or ‘on deck’, but only briefly characterized in an annotated table to confirm their occurrence in the Southern Caribbean. The habitat investigated - steep limestone rocks, likely representing Pleistocene fossil reefs - is similar to deep-water fossil reefs at Barbados of which the sponges were sampled and studied by Van Soest and Stentoft (1988). A comparison is made between the two localities, showing a high degree of similarity in sponge composition: 53% of the present Bonaire-Klein Curaçao species were also retrieved at Barbados. At the level of higher taxa (genera, families) Bonaire-Klein Curaçao shared approximately 80% of its lower mesophotic and upper dysphotic sponge fauna with Barbados, despite a distance between them of 1000 km, indicating high faunal homogeneity. We also preliminarily compared the shallow-water (euphotic) sponge fauna of Curaçao with the combined data available for the Barbados, Bonaire and Klein Curaçao mesophotic and upper dysphotic sponges, which resulted in the conclusion that the two faunas show only little overlap

Date
2014
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
Bonaire
Curacao

A review of coral reef restoration techniques

In this review the following three reef restoration techniques are discussed: 1. Coral gardening, 2. Larval seeding, and 3. Reef balls. These techniques are commonly used in the Caribbean and have widely different approaches. Coral gardening utilize the natural process of asexual reproduction through fragmentation to provide new coral clones for population growth. Healthy wild colonies are once clipped/fragmented and further grown (and cloned multiple times) in an underwater nursery and ultimately transplanted to the reef.
In contrast, larval seeding is based on the sexual reproduction of corals, where large amounts of coral eggs and sperm are collected in the field with subsequent fertilization in the lab. The coral recruits are then made to settle and grown in aquaria until a certain size, after which they are transplanted to the reef. Reef balls are artificial concrete structures designed to provide shoreline protection and sometimes shelter for fish, while at the same time providing substrate for natural recruitment and attachment of benthic organisms such as corals.
A general introduction to coral reproduction is provided to show how life history characteristics are used in restoration efforts and how these can affect the genetic variation within coral populations. The three approaches are compared based on:
1. Survival of fragments and larvae before transplantation to the reef.
2. Survival of transplants at the restoration site.
3. Introduction of exogenous material.
4. Indirect effects of coral restoration on the reef.
5. Genetic diversity.
6. Feasibility and effectiveness.
The main advantages of the production of colonies from fragments are that it bypasses the early larval stages where mortality is high and that new colonies can be grown completely in the field. Generally, the asexual reproduction technique demands less advanced expertise and the public outreach of this method is high because volunteers can easily be incorporated into the program. Furthermore, results become apparent relatively soon since the used species are relatively fast growing. However, there is the risk of creating populations with little genetic variability and the method is only applicable to branching coral species. Presently the method is mainly used for one single species, namely staghorn coral (Acropora cervicornis).
Larval seeding (sexual reproduction) is arguably the best method since it ensures natural genetic diversity and can be used with many species. The disadvantage with this method is that it demands a reasonably high level of expertise and takes more time than the asexual production of new colonies by fragmentation. Also a high percentage of new colonies is lost during the early stages. It is still mostly in the development phase.
Reef balls may increase fish biomass and protect shorelines, but their potential for coral reef restoration is judged to be limited due to the generally low levels of natural recruitment to these structures.
The restoration techniques suffer presently from a lack of independent scientific publications with good data to validate survival, regeneration, and growth rates of colonies in the different phases of the restoration program.
Different populations of the branching Acropora species can differ fundamentally in reproductive characteristics and may respond differently to environmental change. Their difference in strategy may also be a result of adaptation to local environmental factors. All studies and protocols thus stress the necessity to adapt methods to specific locations and environments.
Consideration of genetic factors is essential because the long-term success of restoration efforts (depending on resilience of the populations) may be influenced by genetic diversity of restored coral populations. The use of molecular tools may aid managers in the selection of appropriate propagule sources, guide spatial arrangement of transplants, and help in assessing the success of coral restoration projects by tracking the performance of transplants, thereby generating important data for future coral reef conservation and restoration projects.
It is proposed to study genetic variation in the natural populations around the islands of the Dutch Caribbean and within the various restoration projects in progress. Additionally, it is recommended to assess survival, growth and regeneration of fragments ánd mother colonies in the field. We recommend to combine characteristics of the two main coral restoration techniques (fragmentation and larval rearing) to create a new hybrid approach to increase survival of sexually derived colonies and genetic diversity. In addition, the cost-effectiveness of the larval seeding method should be ascertained and compared with the fragmentation method.
We conclude by pointing out that reef restoration can only be successful if environmental conditions are adequate for survival and growth of coral colonies. This will mean that presently the selection of restoration sites with good environmental conditions is crucial. Thus, active management of anthropogenic stressors is a prerequisite for reef restoration — if a reef is not effectively managed and chronic stressors persist or develop, restoration will ultimately fail. Reef restoration must only be considered as complementary to management tools that address the wider causes of reef degradation.

Date
2015
Data type
Research report
Theme
Research and monitoring
Report number
IMARES C028/14
Geographic location
Bonaire
Curacao
Image
Acropora cervicornis (staghorn coral) restoration

Nutrient Enrichment and Eutrophication on Fringing Coral Reefs of Bonaire and Curaçao, Netherlands Antilles, 2006-2008

Land-based nutrient pollution is a major stressor on coral reef communities around the Caribbean region and globally. To assess the status of nutrient enrichment and eutrophication on Bonaire and Curacao’s coral reefs, we conducted a comparative nutrient monitoring program that included seasonal sampling for nutrients (ammonium, nitrate, DIN, SRP, TDN, TDP), phytoplankton biomass (Chl a), stable nitrogen isotopes (ð15N) in reef macroalgae, and biotic cover (point count analysis of video transect data) of shallow and deep reef sites between March 2006 and June 2008. Ammonium dominated the DIN pool on both islands and the highest concentrations (~10 µM) occurred on Bonaire’s reef sites adjacent to the Cargill salt ponds. DIN concentrations averaged > 1 µM on both shallow and deep reefs of both islands, indicating that these reefs are now above the DIN threshold noted to support expansion of algal turf, macroalgae and coral diseases. SRP concentrations averaged ~ 0.1 µM on both islands, a level that also represents the SRP threshold for eutrophication on coral reefs. DON and DOP dominated the TDN and TDP pools; TDN/TDP ratios averaged 52 on Bonaire and 45 on Curacao, indicating strong P-limitation of algal growth. Mean Chl a concentrations were higher on Curacao (0.25 µg/l) than Bonaire (0.19 µg/l) and the highest Chl a concentrations on both islands occurred on reefs adjacent to urbanized, nutrient enriched areas. In contrast, low Chl a values of ~ 0.05-0.1 µg/l occurred at the upstream reef sites and the offshore reference site, underscoring the importance of land-based nutrient enrichment to microbial growth and eutrophication on fringing reefs of both islands. The highest macroalgal ð15N values (> + 3 ‰) occurred at the MegaPier and Piscadera Bay on Curacao, which reflects the highest watershed sewage nitrogen inputs of all reef sites in the study. The lower ð15N (< + 2 ‰) values at the other reef sites reflect lower levels of sewage treatment as well as contributions from other nitrogen sources (nitrogen fixation, atmospheric inputs) that have lower source ð15N values. Reefs on both islands were dominated (~ 75 % cover) by benthic algae but showed distinct differences in algal composition; Bonaire’s reefs had high cover of turf and low cover of macroalgae compared to the opposite pattern on Curacao. Our results suggest that the recent expansion of benthic algae and loss of coral cover on reefs in Bonaire and Curacao are not simply the result of top-down human pressures (e.g., overfishing) alone, but also reflect strong bottom-up effects from land-based nutrient pollution.

The data of the study can be found here

Date
2011
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire
Curacao