Combined physical, chemical and biological factors shape Alexandrium ostenfeldii blooms in The Netherlands


Contact
Bernd.Krock [ at ] awi.de

Abstract

Harmful algal blooms (HABs) are globally expanding, compromising water quality worldwide. HAB dynamics are determined by a complex interplay of abiotic and biotic factors, and their emergence has often been linked to eutrophication, and more recently to climate change. The dinoflagellate Alexandrium is one of the most widespread HAB genera and its success is based on key functional traits like allelopathy, mixotrophy, cyst formation and nutrient retrieval migrations. Since 2012, dense Alexandrium ostenfeldii blooms (up to 4500 cells mL−1) have recurred annually in a creek located in the southwest of the Netherlands, an area characterized by intense agriculture and aquaculture. We investigated how physical, chemical and biological factors influenced A. ostenfeldii bloom dynamics over three consecutive years (2013–2015). Overall, we found a decrease in the magnitude of the bloom over the years that could largely be linked to changing weather conditions during summer. More specifically, low salinities due to excessive rainfall and increased wind speed corresponded to a delayed A. ostenfeldii bloom with reduced population densities in 2015. Within each year, highest population densities generally corresponded to high temperatures, low DIN:DIP ratios and low grazer densities. Together, our results demonstrate an important role of nutrient availability, absence of grazing, and particularly of the physical environment on the magnitude and duration of A. ostenfeldii blooms. Our results suggest that predicted changes in the physical environment may enhance bloom development in future coastal waters and embayments.



Item Type
Article
Authors
Divisions
Primary Division
Programs
Primary Topic
Publication Status
Published
Eprint ID
44584
DOI https://www.doi.org/10.1016/j.hal.2017.02.004

Cite as
Brandenburg, K. M. , Domis, L. N. d. S. , Wohlrab, S. , Krock, B. , John, U. , van Scheppingen, Y. , van Donk, E. and Van de Waal, D. B. (2017): Combined physical, chemical and biological factors shape Alexandrium ostenfeldii blooms in The Netherlands , Harmful Algae, 63 , pp. 146-153 . doi: https://www.doi.org/10.1016/j.hal.2017.02.004


Download
[thumbnail of Brandenburg_2017.pdf]
Preview
PDF
Brandenburg_2017.pdf

Download (1MB) | Preview
Cite this document as:

Share


Citation

Geographical region
N/A

Research Platforms
N/A

Campaigns
N/A


Actions
Edit Item Edit Item