|Dynamics in carbohydrate composition of Phaeocystis pouchetii colonies during spring blooms in mesocosms|Alderkamp, A.-C.; Nejstgaard, J.C.; Verity, P.G.; Zirbel, M.J.; Sazhin, A.F.; van Rijssel, M. (2006). Dynamics in carbohydrate composition of Phaeocystis pouchetii colonies during spring blooms in mesocosms. J. Sea Res. 55(3): 169-181. dx.doi.org/10.1016/j.seares.2005.10.005
In: Journal of Sea Research. Elsevier/Netherlands Institute for Sea Research: Amsterdam; Den Burg. ISSN 1385-1101, more
Algae; Algal blooms; Mucus; Polysaccharides; Primary production; Phaeocystis Lagerheim, 1893 [WoRMS]; Phaeocystis pouchetii (Hariot) Lagerheim, 1896 [WoRMS]; Marine
algae; polysaccharides; mucus; glucan; laminarin; diel
|Authors|| || Top |
- Alderkamp, A.-C.
- Nejstgaard, J.C.
- Verity, P.G.
- Zirbel, M.J.
- Sazhin, A.F.
- van Rijssel, M.
The colony-forming microalgae Phaeocystis produces two major pools of carbohydrates: mucopolysaccharides in the colony matrix and intracellular storage glucan. Both have different functions and separate degradation pathways in the ecosystem, so a partial precipitation method was developed to distinguish the dynamics of the two pools. Changes in concentration in response to variation in nutrients and irradiance were followed during a spring bloom of Phaeocystis pouchetii colonies in mesocosms near Bergen, Norway. Upon nutrient limitation, the carbohydrate to carbon ratio of the colonies increased from 15% during the growth phase, to more than 50% during the decline phase. During the growth phase of the bloom, the carbohydrate concentration and composition were influenced by irradiance: glucan concentrations showed strong diel dynamics and increased with higher light levels, whereas mucopolysaccharide concentrations were unaffected. During the exponential growth phase, glucan contributed 6-11% to P. pouchetii carbon, depending on the time of the day. During the decline of the bloom, the glucan contribution increased up to 60%. We provide further evidence for the concept that the Phaeocystis colony matrix is built with a relatively small but constant amount of carbohydrates, compared to the large quantities of glucan produced during Phaeocystis spring blooms. Since a major part of Phaeocystis primary production is recycled in the water column by bacteria, this vast glucan injection is a potential determinant of the magnitude and composition of the microbial community following a bloom.