A physicochemically constrained seawater culturing system for production of benthic foraminifera

Abstract

We present an apparatus and procedure for culturing deep‐sea (i.e., bathyal) benthic foraminifera under physicochemically constrained conditions. A 1600‐L recirculating culture system was constructed to contribute negligible trace metal contamination; the system was housed in an environmental room maintained near in situ temperatures but at atmospheric pressure. Peristaltic pumps continuously circulated 3 mL seawater min−1 from the reservoir to 9 to 12 culture chambers. A 2‐mm‐thick layer of high‐purity clay‐sized silica substrate was used to minimize the impact of sedimentary microhabitats. Physicochemical parameters (salinity, alkalinity, pH, temperature) varied <2% throughout two culture experiments. Trace metal concentrations were initially set near open‐ocean values and remained constant (i.e., within our analytical precision) during the experiments. Culture seawater was equilibrated with atmospheric CO2, thus dissolved inorganic carbon δ13C varied ~1‰ over the course of each experiment, reflecting the seasonal atmospheric CO2 isotopic variation. Culture seawater δ18O varied ~0.2‰. Each culture chamber was inoculated with as many as 100 foraminifers of single or multiple species. Pre‐existing foraminiferal calcite was identified by fluorescent labeling prior to specimen introduction into culture. The cultures remained viable for >200 d in each experiment and produced up to 2,800 individuals per culture. The growth and reproduction of benthic foraminifera in a physicochemically constrained culture provide a new method for the experimentation and validation of geochemical proxies.

Heavy metal incorporation in foraminiferal calcite: results from multi-element enrichment culture experiments with &lt;i&gt;Ammonia tepida&lt;/i&gt;

“…De Nooijer et al (2007) also report that Cu binding to calcein is negligible. Hintz et al (2004) argue that measured Mg/Ca ratios in calcein labelled chambers were of the same magnitude as the ratios in unlabelled chambers. Similarly, showed that calcein does not affect the incorporation of the elements Mg and Sr into foraminiferal calcite.…”

“…Although Lu and Allen (2002) report that Cu incorporation competes with Mg and Ca (its incorporation is reduced at increased Ca and/or Mg concentrations), Hintz et al (2004) as well as suggest that the (trace) element incorporation is not affected by the use of calcein. De Nooijer et al (2007) also report that Cu binding to calcein is negligible.…”

Biometry and dissolution features of the benthic foraminifer Ammonia aomoriensis at high pCO2

“…After their classification, the selected specimens were exposed to calcein-stained seawater (4 mg l -1 ) for 2 wk (Bernhard et al 2004, Barras et al 2009) and then placed into 300 ml transparent polycarbonate culture vessels, 30 specimens to a vessel. Each vessel contained 10 small active, 10 larger active and 10 large inactive specimens (Fig.…”

“…Experimental setup. Culturing of Ammonia aomo riensis was performed in a flow-through system following the concept of Hintz et al (2004) (Fig. 1).…”

Modelling δ13C in benthic foraminifera: Insights from model sensitivity experiments

“…Since it is notoriously difficult to culture deep-sea benthic foraminifera in the laboratory under insitu conditions, culture experiments are often limited to shallowwater species (Chandler et al, 1996), or specimen taken from water depths shallower than 250 m (Wilson-Finelli et al, 1998;Havach et al, 2001). Culturing systems like those developed by Hintz et al (2004) have allowed for systematic experiments on deep sea benthic foraminifera (Nomaki et al, 2005(Nomaki et al, , 2006McCorkle et al, 2008;Barras et al, 2010;Filipsson et al, 2010). From a theoretical point of view, progress has mostly been made on planktonic foraminifera Zeebe et al, 1999).…”