Papers by Sander Scheffers
Journal of Coastal Research an International Forum For the Litoral Sciences, Nov 1, 2006
... beaches (Slagbaai, Boca Bartol, Salin a Term, Nukowe) showed minor changes, in particular in ... more ... beaches (Slagbaai, Boca Bartol, Salin a Term, Nukowe) showed minor changes, in particular in ... Along shorelines exposed to the hurricane with the power of thousands of giant ... Extremelyhigh-energy wave deposits inside the Great Barrier Reef, Australia: determining the cause ...
Coastline Reports, 2011
Abstract The 2004 Indian Ocean Tsunami (IOT), generated by an exceptionally strong rupture of the... more Abstract The 2004 Indian Ocean Tsunami (IOT), generated by an exceptionally strong rupture of the Sunda Arc, devastated vast coastal areas all around the Indian Ocean. Besides killing> 230,000 people and massively destroying human infrastructure its impact ...
Coral Reefs, 2010
Large colonies of the ascidian Trididemnum solidum were observed during benthic surveys at Bonair... more Large colonies of the ascidian Trididemnum solidum were observed during benthic surveys at Bonaire, Netherlands Antilles, in January 2009. Mean cover of T. solidum was recorded in a total of 72, randomly located, 30 m long by 1.3-m-wide photo transects, in four replicate transects at three depths (5, 10, and 20 m) in each of six locations along the northwest coast of Bonaire. Locations were chosen due to their remoteness from human development. Photographs were analyzed using CPCe. T. solidum occupied 10.4% ± 3.8 (mean ± SE) of available substrata (sensu at the 20-m site at the Saliña Tern location. Mean T. solidum cover of available substrata (all sites pooled) significantly increased with depth (P £ 0.05) with 0.2% ± 0.1 at 5 m, 3.2% ± 0.6 at 10 m, and 6.3% ± 0.8 at 20 m. While T. solidum colonies occurred on various substrata, aggressive overgrowth of scleractinian corals including Montastraea spp. and Agaricia agaricites and the hydrocoral Millepora spp. were frequently observed. recorded a 900% increase in the number of T. solidum colonies on neighboring Curaçao between 1978 and 1993. Daily availability of larvae ), fast growth rates, and high mobility ) make T. solidum a potentially superior competitor over corals in environments altered by disturbance . High abundance of the aggressive T. solidum ascidian recorded at deeper reefs in this study is of concern and highlights another threat to Bonaire's coral reefs, especially as deeper reefs are considered to be relatively undisturbed .
Page 166. 157 Reading the chapter of extreme wave events in nearshore geo-bio-archives of Bonaire... more Page 166. 157 Reading the chapter of extreme wave events in nearshore geo-bio-archives of Bonaire (Netherlands Antilles) initial results from Lagun and Boka Bartol Max Engel, Andreas Bolten, Helmut Brückner, Gerhard ...
Palaeogeography, Palaeoclimatology, Palaeoecology, 2010
A general lack of accounts of palaeo-tsunami deposits in back barrier environments throughout the... more A general lack of accounts of palaeo-tsunami deposits in back barrier environments throughout the Caribbean and diverging and conflicting interpretation of onshore coarse-clast deposits and landforms on the Leeward Netherlands Antilles (Bonaire, Curaçao, Aruba) encouraged the investigation of coastal stratigraphies along the coast of Bonaire. This work was conducted in order to (i) identify overwash deposits and reconstruct the regional history of high-energy wave events and (ii) provide a scientific basis for local hazard assessment. Vibracores and push cores at the windward (Playa Grandi, Lagun) and leeward coast (Saliña Tam, Klein Bonaire) were analyzed in terms of sedimentary characteristics, geochemical composition and fossil content. The coring sites in exposure to wave energy, foreshore morphology, sediment budgets, relief gradient and vegetation cover. Accordingly the pattern of subsurface overwash deposits varies significantly from site to site depending on exposure direction. For instance, although a prominent layer of sand and shell debris identified at the Lagun embayment (2000-1700 BP) has a counterpart at the sheltered lagoon of Saliña Tam, it is obviously absent at the northern coast. Along the entire island major layers of extreme wave deposits were radiocarbon dated to around 3300 BP, 2000-1700 BP and >500 BP. Sedimentary characteristics, bedforms and geochemical signatures did not provide unequivocal evidence for either tsunami or hurricane storm surge. However, evidence from the taphonomic characteristics of mollusc shells (articulation, fragmentation, rounding, encrustations, abrasion/dissolution) found within candidate coarse sediment layers and by comparison with the marginal sediment input of recent category 4/5 hurricane storm surges, the deposits were classified as representatives for palaeo-tsunami events.
Marine Ecology Progress Series
Abundance, growth rates and nutrient limitation of the heterotrophic bacteria present in the reef... more Abundance, growth rates and nutrient limitation of the heterotrophic bacteria present in the reef water column and reef cavity water were measured on a fringing reef at Curaçao (Netherlands Antilles). Bacterial in situ growth rates were measured using dialysis bags. Nutrient limitation was measured using bioassays with different amendments of inorganic nutrients (nitrate, ammonium, phosphate) and dissolved organic carbon (glucose). Cell sizes were measured in the reef water column and over an intra-cavity gradient inside reef cavities, from the cavity center to the wall of the cavity. Bacterial abundance was lower in cavities, while growth rates were on average 3.6 times higher than in open reef water. The bacterial community in open reef water was limited in its growth by all nutrients, in contrast to cavity water, in which bacteria were limited by phosphate. Cell volumes decreased significantly from open reef water towards the cavity wall. Results suggest that conditions in cavities have a positive effect on bacterial growth. Growth limitation by N is alleviated through enhanced mineralization in cavities. Through rapid exchange with the ambient water, cavities enrich the overlying reef water with inorganic N.
Marine Ecology Progress Series, 2005
Abundance, growth rates and nutrient limitation of the heterotrophic bacteria present in the reef... more Abundance, growth rates and nutrient limitation of the heterotrophic bacteria present in the reef water column and reef cavity water were measured on a fringing reef at Curaçao (Netherlands Antilles). Bacterial in situ growth rates were measured using dialysis bags. Nutrient limitation was measured using bioassays with different amendments of inorganic nutrients (nitrate, ammonium, phosphate) and dissolved organic carbon (glucose). Cell sizes were measured in the reef water column and over an intra-cavity gradient inside reef cavities, from the cavity center to the wall of the cavity. Bacterial abundance was lower in cavities, while growth rates were on average 3.6 times higher than in open reef water. The bacterial community in open reef water was limited in its growth by all nutrients, in contrast to cavity water, in which bacteria were limited by phosphate. Cell volumes decreased significantly from open reef water towards the cavity wall. Results suggest that conditions in cavities have a positive effect on bacterial growth. Growth limitation by N is alleviated through enhanced mineralization in cavities. Through rapid exchange with the ambient water, cavities enrich the overlying reef water with inorganic N.
The island of Bonaire is part of the Leeward Netherlands Antilles and lies 90 km off the Venezuel... more The island of Bonaire is part of the Leeward Netherlands Antilles and lies 90 km off the Venezuelan coast. It mainly consists of two upper cretaceous cores of basalt, andesite, and dacite, fringed by a sequence of Quaternary marine limestone terraces. These well-defined platforms formed by in-situ growth of coral reefs and deposition of coral debris during high stands of sea level and subsequent exposure due to slow tectonic uplift. Bonaire has a semi-arid climate with an average annual precipitation of less than 500 mm, though large year-to-year variation occurs. Due to its peripheral position within the Caribbean hurricane belt the island rarely experiences severe storm events. Nevertheless, along the eastern windward coast several high-energy wave impacts of mid- to late Holocene age have created a well-diversified sedimentary record. Broad ramparts of imbricated coral rubble north of Lac Bai are 4 m high, proceed up to 400 m inland, and follow the shore over a distance of 12 km. Reef communities of the island's eastern sublittoral obviously never regenerated after their destruction during extreme wave events. Furthermore, massive boulders of up to 260 tons are distributed over the broad elevated Pleistocene reef platform deriving from the foreshore zone (Scheffers et al., 2008). The windward nearshore morphological depressions provide excellent conditions for preserving sedimentary inputs of exceptionally large wave impacts. We carried out numerous vibracorings and gravity corings inside shallow sinkholes on the Pleistocene terrace north of Lac Bai and the landward floodplain of the Lagun embayment at Washikemba. Several vibracorings of up to 5 m below surface at Lagun show multiple interruptions of continuous sedimentation patterns by poorly-sorted shell hash within a carbonate-rich matrix of marine origin. The lowermost bioclastic unit dates back before 6000 BP. Within a superimposed layer of pure mangrove peat another cluster of shells, partly broken, is intercalated. 3.25 m below surface, an erosional surface separates the peat from a third mollusc debris facies. The high-energy impact obviously caused sustained modifications of ecological conditions and the sedimentary environment since it destroyed the local mangrove population, indicated by subsequent fine-grained terrestrial sedimentation documented in the cores. In this contribution we present the approach of tracing high-energy deposits in onshore geoarchives of Bonaire's windward coast by implementing a broad interdisciplinary spectrum of analytical methods. It also will be discussed whether the episodic sedimentation patterns identified here are due to tsunamis or exceptionally large tropical storms. Scheffers, S.R., Haviser, J., Browne, T., Scheffers, A. (2008) Tsunamis, hurricanes, the demise of coral reefs and shifts in prehistoric human populations in the Caribbean. Quaternary International, doi:10.1016/j.quaint.2008.07.016.
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Papers by Sander Scheffers