Meesters, E.H.W.G.

The potential Outstanding Universal Value and natural heritage values of Bonaire National Marine Park: an ecological perspective

The Southern Caribbean forms a separate biogeographic province for marine mollusks and marine fish faunas. The terrestrial desert and xeric shrublands and Venezuelan mangrove ecosystems are not yet represented on the World Heritage List or on any national Tentative List. In addition BNMP is located in the Caribbean Islands Hotspot and two Ramsar sites which are also recognized as Key Biodiversity Areas (Important Bird Areas) are found in the boundaries of BNMP. Any terrestrial extension of the proposed nomination could add additional IBAs and include vegetation ecoregions not represented.

However, there are a large number of natural World Heritage Sites with marine values and the combination of mangrove, seagrass and coral, and even saliñas or hypersalinity, is found in several other marine World Heritage Sites. The comparison analysis highlighted the importance of BNMP to make itself distinctive for criteria vii. For criteria ix the difficulty in finding specific information on parrotfish or herbivore biomass, carbonate production or coral reef growth, % hard coral cover and % algal cover suggests that the chosen attributes will fill a gap in ecological processes.

We identify three action points by which to further increase the Bonaire Marine Park nomination prospects as a World Heritage site: a terrestrial extension, a 12 miles zone extension and a transboundary extension. While the last option is expected to increase prospects most, the first and second option are more feasible to establish. Both of them would increase the integrity of Bonaire Marine Park. A terrestrial extension would include xeric shrubland which is not yet represented in any World Heritage site. The 12 miles zone extension would include endangered species, which demonstrates the global importance, as well as new species, which uniqueness still needs to be demonstrated and requires further research.

This report describes the potential Outstanding Universal Value of the Bonaire National Marine Park from an ecological perspective, that is, according to World Heritage natural criteria vii and ix as defined by the Operational Guidelines for the Implementation of the World Heritage Convention (UNESCO, 2013).

The Bonaire National Marine Park is an outstanding example of a fringing coral reef that has evolved to one of the most diverse reef in the Caribbean.

The Bonaire Marine Park, protected since 1979 and declared a National Park in 1999, includes one of the healthiest coral reef in the Caribbean and two Ramsar sites which include mangrove forests and seagrass meadows, globally important for 4 species of endangered species of marine turtles and at least 29 species of migratory waterbirds and a nursery habitat for many reef fish species. The coral reef is characterized by one of the highest cover of living corals in the Caribbean, large schools of grazing fish for biological control of macroalgae and the reef has an important function as a source of larvae for tropical ecosystems downstream.

The seascape of Bonaire Marine Park offers spectacular seaviews of crystal clear water in different shades of blue, contrasted by green coastal vegetation, white sandy beaches, hypersaline saliñas in different shades of pink in the south and steep limestone cliffs in the north. The high visibility of the crystal clear water and colourful underwater scenery offer spectacular and diverse views of large Montastrea coral mounds in the north, a unique double reef parallel to the fringing reef in the south and waving gorgonian fields on the exposed east coast reef. The fringing reef supports large schools of reef fish and over 500 species, including globally threatened species of sharks and rays and a resident population of impressive tarpons.

The proposed property encompasses all the biophysical and ecological processes that characterise a natural and sustainable ecosystem: the highest carbonate production rate in the Caribbean, large coral colonies and high parrotfish grazing rate. These components of a resilient reef, combined with the location of Bonaire outside of the Caribbean hurricane belt, result in the highest hard coral cover and one of the lowest macro algae cover in the Caribbean.

Well established standards of protection, management and monitoring ensure that the coral reef and associated mangrove and seagrass ecosystems of the Bonaire Marine Park will continue to evolve naturally and to support human uses for the foreseeable future in a sustainable way for generations to come. Bonaire is a volcanic oceanic island with steep reef slopes and lies is a small but unique southern Caribbean arid zone outside the principal hurricane belt. This means that the reefs are relatively little- stressed by sediment, freshwater and hurricane disturbance. The island is structurally fortuitous with conditions essential for the long-term support of healthy coral reefs. As reefs in the region continue to rapidly decline, the arid southern Caribbean represents the last best hope for regional coral reefs and the relative importance of Bonaire’s reefs will continue to increase in the future due to their exceptional resilience. The Bonaire Marine Park is the oldest established marine park in the Caribbean and includes two no-use marine reserves and two no-take fish reserves. Fishing on the ecological important parrotfish is traditionally low on Bonaire and has been banned completely in the entire marine park since 2010.

The global comparative analysis identified opportunities to build the case for BNMP as a distinct and important area potentially worthy of international recognition. The comparisons did not clearly highlight how BNMP is irreplaceable, however the findings do suggest that it is representative of a healthy Caribbean coral reef ecosystem. BNMP fills a gap in the marine biogeography as there is no World Heritage Site in the Southern Caribbean.

 

 

Date
2016
Data type
Research report
Theme
Governance
Legislation
Research and monitoring
Report number
C145/14
Geographic location
Bonaire

Marine assessment guideline for BOPEC and Nustar operations

As part of the permit, Rijkswaterstaat requested an ecological monitoring and evaluation framework guideline to accompany the permit-application for the activities of BOPEC (Bonaire) and Nustar (St. Eustatius), related to the activities of the loading and unloading of oil and oil-related-products. IMARES has been asked to develop a tailored guideline to assist in the design of a monitoring plan by BOPEC and Nustar. The current document is the requested guideline. A complete monitoring proposal by the license holder must subsequently be developed on the basis of this guideline. The generic framework developed by Becking and Slijkerman (2012) was applied and made more specific for this guideline. The basic steps undertaken were: 1. Establishing the context in which the project will take place. 2. Scoping of the project activities, their pressures and the environmental descriptors relevant to the potential impact area. 3. Assessment and evaluation of the anticipated pressures on the selected biological and environmental descriptors. The guidance thus contains an overview of relevant activities and their pressures. In addition, biological descriptors were selected based on the most important relationships to the planned activities and anticipated pressures. The scope of monitoring is based on the major linkages between activities, -pressures and -ecosystem descriptors. A distinction is made between baseline and accident monitoring. Baseline monitoring is necessary to guarantee that background levels and patterns of change over time are known. This should be done also at control sites to make sure that a natural pattern (e.g. bleaching) is not confused as an effect of pollution on the impact sites. Both control sites and impact sites to perform baseline monitoring are recommended in this report. Accident monitoring is the assessment of the environmental status following accidents. Polluted sites should be identified and monitored. In parallel, all baseline monitoring should be continued. Due to wind and currents, there is a high likelihood that oil spilled at Nustar will float to the coast of Saba. Therefor it is necessary to check the coast of Saba as well after an oil spill. The baseline monitoring should be a continuous process with and regular effort, while accident related monitoring is incidental, only but directly after a spill or accident. Each type of monitoring requires different frequencies (Chapter 6).

Date
2016
Data type
Research report
Theme
Research and monitoring
Report number
C056/16
Geographic location
Bonaire
St. Eustatius

Distribution and characterization of deep water cyano-bacterial mats occurring along the west coast of Bonaire (Caribbean Netherlands)

Student Report 

Areas like the Caribbean reefs are a biodiversity hotspot. Deeper waters are shown to be of importance for the structure and composition of biological marine communities, but until now only a view studies have been performed on mesophotic reefs (30-100m depth). During three exploratory dives in a submarine along the coast of Bonaire, widespread fields of benthic cyanobacterial mats (BCMs) were found from 45m till 90m depth. These mats are dense structures consisting of different microbial organisms, dominated by cyanobacteria. No previous studies are available of such mats at these depths. Therefore the first aim of this study was to map the distribution of deep BCMs along the west coast of Bonaire, including Klein Bonaire, and to gather more bathymetric data. Almost 30% of the Bonairean west coast contained BCMs. Thereof 44% were found in front of Kralendijk or its suburbs along the coast. BCMs were only found on relative flat and sandy bottoms. Therefore it is thought that the presence of flat and sandy bottoms play a key role in the development of BCMs, but pollution associated with populated areas might play an important role as well. More research is needed to investigate how big the effect of pollution on BCMs formation is and if this can be minimized. 

Subsequently a BCMs characterisation study was performed. Hereby, the focus was on the light availability in the mesophotic waters and the light-harvesting pigments of BCMs. At 14.5m depth light of 600nm and higher frequencies was almost completely filtered out and at a depth of 61.4m the 5% light intensity left ranged between 460nm and 500nm. While analyzing the phycobilisome pigments, clear PUB and PEB absorption peaks were found, but no clear PC and APC peaks were found, which is unexpected since these pigments are thought to be always present. Therefore it would be interesting to perform more research on the presence of the phycobilisomes in these BCMs, to find an explanation for these results. Twelve hydrophobic pigments were found, including zeaxanthin, which originates from cyanobacteria. Deep samples contained more pigments than shallow samples (p=0.005). Moreover, deep samples compared to shallow samples contained on average 47% more of the light absorbing pigment chlorophyll c3 (p < 2.20-16) and 62% less of the light protecting pigment zeaxanthin (p = 4.62-8). These results are according to expectations and indicate that these BCMs are adapted to the life on the ‘dark’ mesophotic reefs.

Date
2016
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire

Occurrence of deep water Cyanobacterial Mats surrounding Bonaire

Student Report 

The abundance of CyanoBacterial Mats (CBMs) at a depth of 50-90m was mapped along the west coast of Bonaire. Simultaneously local conditions (i.e. nutrient concentrations, temperature, salinity, pH, and light intensity) were measured and compared with locations where CBMs were absent. Most CBMs were found near Kralendijk. Differences in temperature and salinity levels between sites with and without CBMs were found, but nutrient concentrations were similar. The species composition in samples of the deep water CBMs were compared with samples of CBMs at 15m depth. All CBMs had a rich species consortia of bacteria, averagely consisting out of 7821 different species (OTUs). The composition between shallow and deep CBMs was found to be significantly different. Moreover, a gradient was seen in the abundances of cyanobacterial genera between the different locations of deep CBMs, which suggests that all deep CBMs have a comparable species composition with different abundances adapted to the local conditions. Overall, the presence of the deep CBMs seems to be related to a combination of multiple parameters: sufficient nutrients which are likely caused by eutrophication events, a relatively flat sandy bottom and low wave energy. 

keywords CyanoBacterial Mats, CBM, deep, genera, Illumina sequencing, species composition

 

Date
2015
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire

Spatio–temporal variation in stable isotope signatures (δ13C and δ15N) of sponges on the Saba Bank

Sponges are ubiquitous on coral reefs, mostly long lived and therefore adaptive to changing environmental conditions. They feed on organic matter withdrawn from the passing water and they may harbor microorganisms (endosymbionts), which contribute to their nutrition. Their diets and stable isotope (SI) fractionation determine the SI signature of the sponge holobiont. Little is known of spatio–temporal variations in SI signatures of d13C and d15N in tropical sponges and whether they reflect variations in the environment. We investigated the SI signatures of seven common sponge species with different functional traits and their potential food sources between 15 and 32 m depth along the S-SE and E-NE side of the Saba Bank, Eastern Caribbean, in October 2011 and October 2013. SI signatures differed significantly between most sponge species, both in mean values and in variation, indicating different food preferences and/or fractionation, inferring sponge species-specific isotopic niche spaces. In 2011, all sponge species at the S-SE side were enriched in d13C compared to the E-NE side. In 2013, SI signatures of sponges did not differ between the two sides and were overall lighter in d13C andd15N than in 2011. Observed spatio–temporal changes in SI in sponges could not be attributed to changes in the SI signatures of their potential food sources, which remained stable with different SI signatures of pelagic (particulate organic matter (POM): d13C -24.9‰, d15N +4.3‰) and benthic-derived food (macroalgae: d13C-15.4‰, d15N +0.8‰). Enriched d13C signatures in sponges at the S-SE side in 2011 are proposed to be attributed to predominantly feeding on benthic-derived C.

This interpretation was supported by significant differences in water mass constituents between sides in October 2011. Elevated NO3 and dissolved organic matter concentrations point toward a stronger reef signal in reef overlying water at the S-SE than N-NE side of the Bank in 2011. The depletions of d13C and d15N in sponges in October 2013 compared to October 2011 concurred with significantly elevated POM concentrations. The contemporaneous decrease in d15N suggests that sponges obtain their N mostly from benthic-derived food with a lower d15N than pelagic food. Average proportional feeding on available sources varied between sponge species and ranged from 20% to 50% for benthic and 50% to 80% for pelagic-derived food, assuming trophic enrichment factors of 0.5‰ ± sd 0.5 for d13C and 3‰ ± sd 0.5 for d15N for sponges. We suggest that observed variation of SI in sponges between sides and years were the result of shifts in the proportion of ingested benthic- and pelagic-derived organic matter driven by environmental changes. We show that sponge SI signatures reflect environmental variability in space and time on the Saba Bank and that SI of sponges irrespective of their species-specific traits move in a similar direction in response to these environmental changes.

Date
2018
Data type
Scientific article
Theme
Research and monitoring
Document
Journal
Geographic location
Saba bank

News item: Hyperspectral Coral Reef Classification (HCRC)

The Dutch Caribbean island Bonaire has protected its marine resources for more than 35 years and has been ranked as one of the Caribbean’s top dive destinations much due to its wide range of easy accessible diving sites, clear waters and relatively healthy coral reef ecosystem. The importance of coral reefs is multifunctional and provides ecosystem services not only to attract tourism and therefore income, but also as a natural barrier to protect the coast, and as a habitat for many species, providing food as well.

The general consensus is that the extent and biodiversity of Bonaire’s coral reef is decreasing due to local and regional anthropogenic and global climate pressures. However, the last extensive study of the coral coverage of the reef ecosystem was performed in 1985 by Van Duyl who created an underwater atlas of Bonaire and Curaçao. In order to update this atlas of Bonaire’s coral reefs, a hyperspectral mapping campaign was performed in October 2013 using the Wageningen UR Hyperspectral Mapping System (HYMSY) with 101 spectral channels.

In June 2016, with the help of STINAPA Bonaire, Sander Mucher and Erik Meesters were able to perform an extensive diving campaign to collect in-situ information in 18 transects perpendicular to the coastline across the western coast. Detailed photographs of the sea bottom were taken by diving from a depth of 20-30 meters towards sea level on the coast. Photographs were geotagged by another person snorkelling exactly above the diver with a GPS in a waterproof box and making overview pictures of the sea bottom as well. This in-situ information was used to interpret the hyperspectral imagery made by the HYMSY camera.      

The HYMSY camera consists of a custom pushbroom spectrometer (range 450–950nm, FWHM 9nm, ~20 lines/s, 328 pixels/line), a consumer camera (collecting 16MPix raw image every 2 seconds), a GPS-Inertia Navigation System (GPS-INS), and synchronization and data storage units. The weight of the system at take-off is 2.0kg allowing it to be mounted on varying platforms. On Bonaire the system was flown on two platforms: 1) on a Cessna airplane to provide a coverage for whole coastline, and 2) on a kite pulled by boat or car to provide a subset coverage in higher resolution. With the Cessna the whole west coast of the island was mapped. The Aerial images were collected at 150mm ground sampling distance (GSD) and the hyperspectral data in 2m GSD. The data were mosaicked and geo-rectified to form hyperspectral maps of the western and southern coastal area of Bonaire.

In order to interpret the data more consistently, the hyperspectral data were corrected for the water depth into at-ground-reflectance factor units. A bathymetric model was used for the calibration of the hyperspectral imagery based on a former field campaign by measuring water depth at specific locations along the western coast. The final bathymetric model that we used was based on extrapolation of the terrestrial digital elevation model through fitting with additional in-situ bathymetric measurements on sea. A more detailed bathymetric model would of course have been preferred to calibrate the hyperspectral data with a 1 meter spatial resolution. Due the limited penetration of green and red light though the water, it was decided to use only the first 15 hyperspectral bands in the violet-blue -cyan till green range (Band 1 = 450.0 nm to Band 15 = 520.0 nm). This means that spectral measurements can be made to a maximum depth of 20 – 30 meters.

The classification of the hyperspectral data is almost finished and is classified in simple classes such as sand, pavement, rubble, soft and hard corals and various mixtures of these at a pixel level of 1 meter spatial resolution. Examples of the coral reef hyperspectral classification are given below. The new map is freely accessible via DCBD

 

Date
2016
Data type
Media
Theme
Education and outreach
Research and monitoring
Geographic location
Bonaire

Is Saba Bank becoming a ‘sponge reef’?

Poster:

Objectives

• Assess sponge and coral cover
• Quantify the diversity and health of the sponge assemblages on Saba Bank 

Date
2016
Data type
Maps and Charts
Theme
Research and monitoring
Geographic location
Saba bank

Wave-swept coralliths of Saba Bank, Dutch Caribbean

During a recent reef coral survey at the submarine Saba Bank (Eastern Caribbean), an uncommon and diverse assemblage of unattached scleractinian corals (coralliths) was encountered, which has not been reported from the Atlantic before. Four different types of these free-living (unattached) corals were distinguished. They were observed on a relatively flat seafloor (15–20 m deep) with poor coral cover and full exposure to oceanic swell. Much of the substratum was not consolidated and consisted mainly of sand and fragments of branching coralline algae. One of the four types is the (1) anthocyathus stage in the life history of the free-living species Manicina areolata and Meandrina danae. The other three are coralliths formed as ecophenotypic varieties: (2) spheroidal–amoeboidal (= globular and (sub)massive) in Porites astreoides, Siderastrea radians, S. siderea, and Stephanocoenia intersepta; (3) tumbleweed-like (= globular and ramose) in Porites divaricata and P. furcata; and (4) discoidal (flat and circular with short branches) in Madracis decactis and possibly in M. cf. auretenra. This assemblage of free-living corals is likely related to a combination of abiotic factors consisting of wave exposure (swell), depths that waves can reach, a horizontal sea floor with little relief, an unconsolidated substratum, and low coral cover.

Date
2017
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Saba bank

Saba Bank Symposium: summary and recommendations

Introduction:

Since 2010, the Saba Bank falls under the jurisdiction of The Netherlands. Spanning an area of 2000km2, the Saba Bank houses the largest coral reef in the Caribbean Netherlands with a great diversity of species. The past 5 years the Dutch Ministry of Economic Affairs has funded research on the biodiversity, health and ecological functioning of the bank. On 8 December 2016 The Saba Bank Symposium was organised with 11 speakers and a panel discussion on the knowledge gaps and future perspectives of the bank. With this letter we provide an overview of results and future directions for policy and research.

Key message:

We need to improve the resilience of the Saba Bank to cope with the effects of climate change and fisheries. 

Date
2017
Data type
Research report
Theme
Research and monitoring
Report number
Policy Letter 1700555 JA-bc /BO-11- 019.02-008
Geographic location
Saba bank

40 Years of benthic community change on the Caribbean reefs of Curaçao and Bonaire: the rise of slimy cyanobacterial mats

Over the past decades numerous studies have reported declines in stony corals and, in many cases, phase shifts to fleshy macroalgae. However, long-term studies documenting changes in other benthic reef organisms are scarce. Here, we studied changes in cover of corals, algal turfs, benthic cyanobacterial mats, macroalgae, sponges and crustose coralline algae at four reef sites of the Caribbean islands of Curaçao and Bonaire over a time span of 40 yr. Permanent 9 m2quadrats at 10, 20, 30 and 40 m depth were photographed at 3- to 6-yr intervals from 1973 to 2013. The temporal and spatial dynamics in the six dominant benthic groups were assessed based on image point-analysis. Our results show consistent patterns of benthic community change with a decrease in the cover of calcifying organisms across all sites and depths from 32.6 (1973) to 9.2% (2013) for corals and from 6.4 to 1% for crustose coralline algae. Initially, coral cover was replaced by algal turfs increasing from 24.5 (1973) to 38% around the early 1990s. Fleshy macroalgae, still absent in 1973, also proliferated covering 12% of the substratum approximately 20 yr later. However, these new dominants largely declined in abundance from 2002 to 2013 (11 and 2%, respectively), marking the rise of benthic cyanobacterial mats. Cyanobacterial mats became the most dominant benthic component increasing from a mere 7.1 (2002) to 22.2% (2013). The observed increase was paralleled by a small but significant increase in sponge cover (0.5 to 2.3%). Strikingly, this pattern of degradation and phase change occurred over the reef slope down to mesophotic depths of 40 m. These findings suggest that reefs dominated by algae may be less stable than previously thought and that the next phase may be the dominance of slimy cyanobacterial mats with some sponges.

Date
2017
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
Bonaire
Curacao