Numbers, sizes, and types of diatoms around estuaries for a diatom test

Eiji Kakizaki, Shuji Kozawa, Masahiro Sakai, Nobuhiro Yukawa

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13 Citations (Scopus)


We collected 68 fresh, brackish, and seawater samples from various sites around the estuaries of 2 rivers at high and low tides. Seawater flowed approximately 2.4 (salinity, 2.2% at the site) and 1.2 km (1.8%) upstream of the estuaries, but the surface comprised essentially fresh water up to the mouth. Sites contained 69 to 22,200 diatoms/50 mL of water, and the numbers varied by depth and at sites separated by only approximately 1.2 km. Diatoms ranged from 2.8 to 429 Km (mean range, 16.1Y59.2 Km) in size. Large pennate diatoms populated fresh water areas, and most sedimented before reaching the sea. Numbers of pennate diatoms of less than 20 Km were decreased in areas of seawater. Numbers of centric diatoms tended to increase nearer the sea, and seawater contained large centric diatoms. Brackish water containing large volumes of seawater was easily discriminated by assemblages of marine diatoms, unlike that containing a little seawater, because marine diatoms could be found in fresh water around estuaries. Tides and the nature of the river often altered diatomaceous assemblages at the same estuarial sites. Caution is recommended for forensic interpretation of aqueous media to deduce drowning sites.

Original languageEnglish
Pages (from-to)269-274
Number of pages6
JournalAmerican Journal of Forensic Medicine and Pathology
Issue number3
Publication statusPublished - 09-2011
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Pathology and Forensic Medicine


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