pH Regulation and Tissue Coordination Pathways Promote Calcium Carbonate Bioerosion by Excavating Sponges.

Coral reefs are threatened by a multitude of environmental and biotic influences. Among these, excavating sponges raise particular concern since they bore into coral skeleton forming extensive cavities which lead to weakening and loss of reef structures. Sponge bioerosion is achieved by a combination of chemical dissolution and mechanical chip removal and ocean acidification has been shown to accelerate bioerosion rates.

In-situ incubation of a coral patch for community-scale assessment of metabolic and chemical processes on a reef slope.

Anthropogenic pressures threaten the health of coral reefs globally. Some of these pressures directly affect coral functioning, while others are indirect, for example by promoting the capacity of bioeroders to dissolve coral aragonite. To assess the coral reef status, it is necessary to validate community-scale measurements of metabolic and geochemical processes in the field, by determining fluxes from enclosed coral reef patches.

Effect of different seawater Mg concentrations on calcification in two benthic foraminifers.

Magnesium, incorporated in foraminiferal calcite (Mg/Ca), is used intensively to reconstruct past seawater temperatures but, in addition to temperature, the Mg/Ca of foraminiferal tests also depends on the ratio of Mg and Ca in seawater (Mg/Ca). The physiological mechanisms responsible for these proxy relationships are still unknown. This culture study investigates the impact of different seawater [Mg] on calcification in two benthic foraminiferal species precipitating contrasting Mg/Ca: , producing low-Mg calcite and , producing intermediate-Mg calcite.

Unexpected biotic resilience on the Japanese seafloor caused by the 2011 Tōhoku-Oki tsunami.

On March 11(th), 2011 the Mw 9.0 2011 Tōhoku-Oki earthquake resulted in a tsunami which caused major devastation in coastal areas. Along the Japanese NE coast, tsunami waves reached maximum run-ups of 40 m, and travelled kilometers inland.

TRANSCRIPTOME ANALYSES REVEAL DIFFERENTIAL GENE EXPRESSION PATTERNS BETWEEN THE LIFE-CYCLE STAGES OF EMILIANIA HUXLEYI (HAPTOPHYTA) AND REFLECT SPECIALIZATION TO DIFFERENT ECOLOGICAL NICHES(1).

Coccolithophores, especially the abundant, cosmopolitan species Emiliania huxleyi (Lohmann) W. W. Hay et H.

Foraminifera promote calcification by elevating their intracellular pH.

Surface seawaters are supersaturated with respect to calcite, but high concentrations of magnesium prevent spontaneous nucleation and growth of crystals. Foraminifera are the most widespread group of calcifying organisms and generally produce calcite with a low Mg content, indicating that they actively remove Mg(2+) from vacuolized seawater before calcite precipitation. However, one order of foraminifera has evolved a calcification pathway, by which it produces calcite with a very high Mg content, suggesting that these species do not alter the Mg/Ca ratio of vacuolized seawater considerably.