The cadmium-phosphate relationship in brine: biological versus physical control over micronutrients in sea ice environments

Hendry, Katharine Rosemary, Rickaby, Rosalind E. M., De Hoog, Jan C. M., Weston, Keith and Rehkamper, Mark 2010. The cadmium-phosphate relationship in brine: biological versus physical control over micronutrients in sea ice environments. Antarctic Science 22 (1) , pp. 11-18. 10.1017/S0954102009990381

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Abstract

Despite supporting productive ecosystems in the high latitudes, the relationship between macro- and micronutrients in sea ice environments and their impact on surface productivity is poorly documented. In seawater, the macronutrient phosphate and the micronutrient cadmium follow similar distributions, which are controlled by biological processes in surface waters. We investigated cadmium and phosphate in sea ice brine, and the biological and physical processes controlling their distribution. Cadmium concentrations in sea ice brine ranged from 0.09–2.4 nmol kg-1, and correlated well with salinity. Our results show that micronutrients in sea ice are most probably sourced from the seawater from which it froze rather than external sources such as atmospheric deposition. The weak correlation between sea ice cadmium and phosphate, and the positive relationship between cadmium and biomass, suggests against biological uptake being a principal control over micronutrient distribution even in a highly productive setting. Instead, brine expulsion and dilution play a dominant role in cadmium distribution in sea ice. Nutrient dilution within brine channels during melting, and contrasting sea ice and open water phytoplankton populations, suggests that late spring sea ice is not a significant source of nutrients or biomass to seawater. We suggest that future changes in sea ice seasonality may impact nutrient distribution and Antarctic marine ecosystems.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Subjects:	G Geography. Anthropology. Recreation > GC Oceanography
Uncontrolled Keywords:	Antarctica coastal waters ; Biogeochemistry ; Nnutrients ; Trace elements
Additional Information:	Pdf uploaded in accordance with publisher's policy at http://www.sherpa.ac.uk/romeo/issn/0954-1020/ (accessed 21/02/2014).
Publisher:	Cambridge University Press
ISSN:	0954-1020
Date of First Compliant Deposit:	30 March 2016
Last Modified:	11 May 2023 11:40
URI:	https://orca.cardiff.ac.uk/id/eprint/7522

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