Light microscopy identification notes

Valve View: Lanceolate and long. Striation is present and the central raphe is keeled, but both of these can be difficult to see in live specimens under a light microscope (up to x400 objection).

Girdle View: Long rectangular shape

Two large chloroplasts per cell. Oftentimes a gap can be seen in the centre of the cell between the two chloroplasts. Found in colonies of cells sliding against each other, extending and contracting.

Apical axis (μm)	Transapical axis (width) (μm)	Pervalvar axis (height) (μm)	Striae in 10 μm
68 - 250	5 - 8	5 - 10	19 - 24

Of the individual cells measured off the Norfolk coast for this project thus far, the range of apical axes for B. paxillifera has been 62 μm - 116 μm, with a mean average of 90 μm. The range of transapical axes was 3 μm - 7 μm, with a mean average of 5 μm.

References

Hasle, G.R., and Syvertsen, E.E. (1997) Identifying Marine Phytoplankton. pp. 293. Edited by C.R. Tomas. San Diego: Academic Press.

Hoppenrath, M., Elbrächter, M., Drebes, G. (2009) Marine Phytoplankton. pp. 108. Edited by Prof. Dr. Dr. h.c. Volker Mosbrugger. Stuttgart: E. Schweizerbart’sche Verlagsbuchhandlung (Nägele u. Obermiller)

Kraberg, A., Baumann, M and Dürselen, C-D,. (2010) Coastal Phytoplankton Photo Guide for Northern European Seas. pp. 99. München: Verlag Dr. Friedrich Pfeil.

Spaulding, S. (2018) Bacillaria paxillifera. Available at: https://diatoms.org/species/bacillaria_paxillifera (Accessed 24 April 2024)

2023/24	King's Lynn estuary	Wells Quay	Cromer Pier	Gorleston Pier
April		✅	✅	✅
May		✅	✅	✅
June		✅		✅
July			✅	✅
August		✅		✅
September	✅			✅
October	✅			✅
November	✅	✅	✅	✅
December	no data	✅	✅	✅
January		✅	✅	✅
February		✅	✅	✅
March	✅	✅	✅	✅