Heteroxanthin as a pigment biomarker for Gonyostomum semen (Raphidophyceae)

Area of Science:

• Environmental Science
• Limnology
• Phycology

Background:

• Algal community shifts are critical environmental issues, but understanding their drivers is hindered by a lack of long-term data.
• Gonyostomum semen, a freshwater alga, has increased in Scandinavian lakes, causing ecological and recreational problems.
• Identifying reliable biomarkers in sediment cores is crucial for reconstructing long-term ecological histories.

Purpose of the Study:

• To identify specific and persistent biomarkers for Gonyostomum semen in cultured strains.
• To evaluate the suitability of identified pigments as biomarkers in paleolimnological studies using dated sediment cores.
• To establish long-term data for understanding the drivers of Gonyostomum semen proliferation.

Main Methods:

• Pigment composition analysis of Gonyostomum semen strains using high-performance liquid chromatography-photometric diode arrays (HPLC-PDA).
• Confirmation of pigment identity using liquid chromatography-mass spectrometry (LC-MS).
• Analysis of dated sediment core samples from Lake Lundebyvann, Norway, for biomarker detection.

Main Results:

• The pigment heteroxanthin was detected in all examined Gonyostomum semen strains, along with chlorophyll a.
• Heteroxanthin was successfully identified in sediment core samples up to 60 years old using HPLC-PDA.
• Heteroxanthin was not detected in other common Norwegian phytoplankton species, confirming its specificity.

Conclusions:

• Heteroxanthin is confirmed as a suitable pigment biomarker for Gonyostomum semen.
• This biomarker can be effectively utilized in paleolimnological studies to reconstruct the historical presence of Gonyostomum semen.
• The findings facilitate improved understanding of the long-term drivers behind Gonyostomum semen blooms in lakes.