Dynamics in carbohydrate composition of Phaeocystis pouchetii colonies during spring blooms in mesocosms

AC Alderkamp*, JC Nejstgaard, PG Verity, MJ Zirbel, AF Sazhin, M van Rijssel, V.N Sazhin

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

25 Citations (Scopus)

Abstract

The colony-forming microalgae Phaeocystis produces two major pools of carbohydrates: in 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 Phacocystis 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. (c) 2005 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)169-181
Number of pages13
JournalJournal of Sea Research
Volume55
Issue number3
DOIs
Publication statusPublished - Apr-2006

Keywords

  • algae
  • polysaccharides
  • mucus
  • glucan
  • laminarin
  • diel
  • BELGIAN COASTAL WATERS
  • NORTH-SEA
  • FOOD-WEB
  • PRYMNESIOPHYCEAE COLONIES
  • POLYSACCHARIDE HYDROLYSIS
  • BIOCHEMICAL-COMPOSITION
  • SOUTHERN-OCEAN
  • VERTICAL FLUX
  • TROPHIC FATE
  • PHYTOPLANKTON

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