Details

Autor(en) / Beteiligte

• Poulton, Alex J.
• Mayers, Kyle M.J.
• Daniels, Christopher J.
• Stinchcombe, Mark C.
• Woodward, E. Malcolm S.
• Hopkins, Joanne
• Wihsgott, Julianne U.
• Widdicombe, Claire E.

Titel

Dissolution Dominates Silica Cycling in a Shelf Sea Autumn Bloom

Ist Teil von

• Geophysical research letters, 2019-06, Vol.46 (12), p.6765-6774

Ort / Verlag

Washington: John Wiley & Sons, Inc

Erscheinungsjahr

2019

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Autumn phytoplankton blooms represent key periods of production in temperate and high‐latitude seas. Biogenic silica (bSiO2) production, dissolution, and standing stocks were determined in the Celtic Sea (United Kingdom) during November 2014. Dissolution rates were in excess of bSiO2 production, indicating a net loss of bSiO2. Estimated diatom bSiO2 contributed ≤10% to total bSiO2, with detrital bSiO2 supporting rapid Si cycling. Based on the average biomass‐specific dissolution rate (0.2 day−1), 3 weeks would be needed to dissolve 99% of the bSiO2 present. Negative net bSiO2 production was associated with low‐light conditions (<4 E·m−2·day−1). Our observations imply that dissolution dominates Si cycling during autumn, with low‐light conditions also likely to influence Si cycling during winter and early spring. Plain Language Summary Small marine microalgae called diatoms are responsible for significant levels of primary production in support of marine ecosystems. Diatom cells are formed from silica dissolved in seawater; however, diatom cells may also readily dissolve in seawater. Observationsof silica uptake and dissolution during the autumn period of enhanced microalgal productivity in a shelf seafound a nonliving detrital pool of diatomaceous material, which was dissolving faster than the few diatomspresent were making new cells. These observations highlight that certain periods of the year may be associated with rapid rates of dissolution and hence are important for recycling of material prior to the winter period when nutrient budgets in the water‐column are set for the following year. Key Points Rates of biogenic silica dissolution were greater than rates of production during late autumn A large fraction of detrital biogenic silica was present, with living biomass a minor fraction Low‐light and high detrital biogenic silica promotes net dissolution rather than net production