Ocean acidification not likely to affect the survival and fitness of two yemperate benthic foraminiferal species: results from culture experiments

Specimens of Bolivina argentea and Bulimina marginata, two widely distributed temperate benthic foraminiferal species, were cultured at constant temperature and controlled pCO2 (ambient, 1000 ppmv, and 2000 ppmv) for six weeks to assess the effect of elevated atmospheric CO2 concentrations on survival and fitness using Adenosine Triphosphate (ATP) analyses and on shell microfabric using high-resolution SEM and image analysis. To characterize the carbonate chemistry of the incubation seawater, total alkalinity and dissolved inorganic carbon were measured approximately every two weeks. Survival and fitness were not directly affected by elevated pCO2 and the concomitant decrease in seawater pH and calcite saturation states (Omega c), even when seawater was undersaturated with respect to calcite. These results differ from some previous observations that ocean acidification can cause a variety of effects on benthic foraminifera, including test dissolution, decreased growth, and mottling (loss of symbiont color in symbiont-bearing species), suggesting that the benthic foraminiferal response to ocean acidification may be species specific. If so, this implies that ocean acidification may lead to ecological winners and losers even within the same taxonomic group.

Benthic and fish community composition as well as water quality along the Thousand Islands north of the megacity Jakarta, Indonesia

Worldwide, coral reefs are challenged by multiple stressors due to growing urbanization, industrialization and coastal development. Coral reefs along the Thousand Islands off Jakarta, one of the largest megacities worldwide, have degraded dramatically over recent decades. The shift and decline in coral cover and composition has been extensively studied with a focus on large-scale gradients (i.e. regional drivers), however special focus on local drivers in shaping spatial community composition is still lacking. Here, the spatial impact of anthropogenic stressors on local and regional scales on coral reefs north of Jakarta was investigated. Results indicate that the direct impact of Jakarta is mainly restricted to inshore reefs, separating reefs in Jakarta Bay from reefs along the Thousand Islands further north. A spatial patchwork of differentially degraded reefs is present along the islands as a result of localized anthropogenic effects rather than regional gradients. Pollution is the main anthropogenic stressor, with over 80 % of variation in benthic community composition driven by sedimentation rate, NO2, PO4 and Chlorophyll a. Thus, the spatial structure of reefs is directly related to intense anthropogenic pressure from local as well as regional sources. Therefore, improved spatial management that accounts for both local and regional stressors is needed for effective marine conservation.

Absolute abundances of benthic and planktonic foraminifers in samples of ODP Hole 149-901A (Table 1)

Dark gray laminated silty claystones (Unit II) drilled at Site 901 contain Tithonian benthic foraminifer assemblages that indicate a neritic depositional environment and probably dysaerobic bottom-water conditions. Three benthic foraminifer zones are distinguished within Unit II. The upper part of the unit is dominated by Spirillina polygyrata, contains Globospirillina spp. (Samples 149-901A-3R-1, 10-12 cm, to 149-901A-3R-1, 75-77 cm) and is interpreted as late Tithonian. Samples 149-901A-3R-1, 87-89 cm, to 149-901A-6R-1, 74-76 cm, contain Epistomina uhligi and Lingulina franconica and are probably early Tithonian. The early Tithonian Neobulimina atlantica Zone is characterized by the occurrence of the zonal marker and Epistomina uhligi and reaches from Sample 149-901A-6R-1, 128-130 cm, to the base of the drilled-sequence. The sediments and benthic foraminiferal assemblage characteristics of the Tithonian-aged sequence in Hole 901A are unknown elsewhere in the Atlantic and may represent deposition in a marginal shelf basin with increased terrigenous and organic flux.

Simulation Model of Benthic Antarctic Assemblages (SIMBAA), link to PC-executable

SIMBAA is a spatially explicit, individual-based simulation model. It was developed to analyse the response of populations of Antarctic benthic species and their diversity to iceberg scouring. This disturbance is causing a high local mortality providing potential space for new colonisation. Traits can be attributed to model species, e.g. in terms of reproduction, dispersal, and life span. Physical disturbances can be designed in space and time, e.g. in terms of size, shape, and frequency. Environmental heterogeneity can be considered by cell-specific capacities to host a certain number of individuals. When grid cells become empty (after a disturbance event or due to natural mortality of of an individual), a lottery decides which individual from which species stored in a pool of candidates (for this cell) will recruit in that cell. After a defined period the individuals become mature and their offspring are dispersed and stored in the pool of candidates. The biological parameters and disturbance regimes decide on how long an individual lives. Temporal development of single populations of species as well as Shannon diversity are depicted in the main window graphically and primary values are listed. Examples for simulations can be loaded and saved as sgf-files. The results are also shown in an additional window in a dimensionless area with 50 x 50 cells, which contain single individuals depicted as circles; their colour indicates the assignment to the self-designed model species and the size represents their age. Dominant species per cell and disturbed areas can also be depicted. Output of simulation runs can be saved as images, which can be assembled to video-clips by standard computer programs (see GIF-examples of which "Demo 1" represents the response of the Antarctic benthos to iceberg scouring and "Demo 2" represents a simulation of a deep-sea benthic habitat).

Oxygen isotope composition of benthic foraminifera ofthe Florida Street

We present a new method for the quantitative reconstruction of upper ocean flows for during times in the past. For the warm (T>5°C) surface ocean, density can be accurately reconstructed from calcite precipitated in equilibrium with seawater, as both of these properties increase with decreasing temperature and increasing salinity. Vertical density profiles can be reconstructed from the oxygen isotopic composition of benthic foraminifera. The net volume transport between two vertical density profiles can be calculated using the geostrophic method. Using benthic foraminifera from surface sediment samples from either side of the Florida Straits (Florida Keys and Little Bahama Bank), we reconstruct two vertical density profiles and calculate a volume transport of 32 Sv using this method. This agrees well with estimates from physical oceanographic methods of 30-32 Sv for the mean annual volume transport. We explore the sensitivity of this technique to various changes in the relationship between temperature and salinity as well as salinity and the oxygen isotopic composition of seawater.