Studies in Fe bioavailability : co-limitation of primary productivity by iron, light, and nitrate in the Beaufort Sea, and direct iron-siderophore uptake mechanisms in Fe deficient phytoplankton ...

• Main Author: Taylor, Rebecca Lynn
• Format: Text
• Language: English
• Published: University of British Columbia 2011
• Subjects: Arctic; Arctic Ocean; Beaufort Sea; Phytoplankton
• Online Access: https://dx.doi.org/10.14288/1.0053264; https://doi.library.ubc.ca/10.14288/1.0053264

This study explores two relevant questions in the realm of iron (Fe) bioavailability to phytoplankton. First, does Fe availability limit (or co-limit) growth of indigenous plankton communities in the Arctic Ocean? Second, can phytoplankton internalize ferrated siderophores with a non-reductive uptake mechanism? To address the first question, an 8-day grow out experiment was conducted in the Beaufort Sea in early September 2009, during which light, Fe, and nitrate (NO₃⁻) levels were manipulated. Bottles were sampled on days 0, 2, 4, 6, and 8 for accessory pigments, size-fractionated chlorophyll α, phytoplankton abundance and composition, nutrients, Fe quotas and uptake rates. It was found that NO₃⁻ was limiting plankton growth at the time of sampling. The community also appeared to be light limited. Additionally, co-limitation of primary production by Fe and light at light levels ≤ 10 % surface irradiance (I₀) was observed. These results have interesting implications about how the seasonality of NO₃⁻, light, ...