The second is from a salt-water sample I just took. It shows two orientations of the same species.
2 diatoms
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Charles Krebs
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2 diatoms
The first is a freshwater specimen I photographed a few years back, but just recently came across this file.
The second is from a salt-water sample I just took. It shows two orientations of the same species.
The second is from a salt-water sample I just took. It shows two orientations of the same species.
Ha, nice one Charlie, the saltwater thingy is Coscinodiscus wailesii, a battleship of a diatom. It's an introduced nuisance species, can form blooms that produce a lot of mucus. When the bloom dies, the breakdown of the mucus takes all oxygen out of the water. Some decades ago it regularly bloomed along the south coast of England, and they were talking about meters (!) of mucal slib on the sea floor.
Rene
Rene
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Charles Krebs
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René,
Thanks for the identification. Interesting. I've dragged my little plankton net a few times here in Puget Sound (WA) this summer and had always come up with a real mixed "soup" of phytoplankton and zooplankton. In this last sampling, the water was quite "clear" and devoid of the species I had found all summer, but it had a very large number of this (large!) diatom.
Thanks for the identification. Interesting. I've dragged my little plankton net a few times here in Puget Sound (WA) this summer and had always come up with a real mixed "soup" of phytoplankton and zooplankton. In this last sampling, the water was quite "clear" and devoid of the species I had found all summer, but it had a very large number of this (large!) diatom.
Funny, I never thought of concept with diatoms. What was it's "native" geographical location?It's an introduced nuisance species
Hi Charlie,
Nothing more I can add to this:
Distribution
Coscinodicus wailesii has been found throughout the Pacific Ocean since its first description. It is an invasive species in the Atlantic Ocean, first observed in 1977 in the English Channel (Boalch & Harbour 1977), misidentified as Coscinodiscus nobilis, and along the U.S. East coast in the late 1970s. It is absent from a 1964-74 survey of diatoms along the U.S. East coast (Marshall 1976). It appeared in Narragansett Bay in 1978 (Hargraves unpubl.; and found in the Chesapeake Bay in 1980 (Marshall, 1982). The earlier report of the species from Chesapeake Bay (Patten et al. 1963) cannot be confirmed. During the next decade it spread to the South Atlantic, both eastern (Senn 2002) and western (Fernandes et al. 2001; Lutz et al. 2006) sides. It was not present in the Indian Ocean during the 1964-65 R/V ‘Meteor’ expedition according to Simonsen (1974); current status in the Indian Ocean could not be confirmed but it may have also invaded there. Its ability to survive long periods in darkness (Nagai 1995) suggests that transport in ballast water may have aided in its distribution. It is mostly found in coastal and shelf waters, and is apparently absent from boreal and polar environments.
Author(s): Hargraves, Paul
Comment (0)
Nothing more I can add to this:
Distribution
Coscinodicus wailesii has been found throughout the Pacific Ocean since its first description. It is an invasive species in the Atlantic Ocean, first observed in 1977 in the English Channel (Boalch & Harbour 1977), misidentified as Coscinodiscus nobilis, and along the U.S. East coast in the late 1970s. It is absent from a 1964-74 survey of diatoms along the U.S. East coast (Marshall 1976). It appeared in Narragansett Bay in 1978 (Hargraves unpubl.; and found in the Chesapeake Bay in 1980 (Marshall, 1982). The earlier report of the species from Chesapeake Bay (Patten et al. 1963) cannot be confirmed. During the next decade it spread to the South Atlantic, both eastern (Senn 2002) and western (Fernandes et al. 2001; Lutz et al. 2006) sides. It was not present in the Indian Ocean during the 1964-65 R/V ‘Meteor’ expedition according to Simonsen (1974); current status in the Indian Ocean could not be confirmed but it may have also invaded there. Its ability to survive long periods in darkness (Nagai 1995) suggests that transport in ballast water may have aided in its distribution. It is mostly found in coastal and shelf waters, and is apparently absent from boreal and polar environments.
Author(s): Hargraves, Paul
Comment (0)
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Charles Krebs
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- Location: Issaquah, WA USA
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Abel,
As I recall, the first image was taken with the S Plan Apo 100/1.40 using the Zeiss "Ultra-Condenser" (darkfield, oil). That objective has an adjustable aperture to permit darkfield.
The drum shaped diatoms (Coscinodiscus wailesii ... thanks Rene) in the second image are very large diatoms. That was taken in brightfield with a 10X objective (image cropped a fair amount).
As I recall, the first image was taken with the S Plan Apo 100/1.40 using the Zeiss "Ultra-Condenser" (darkfield, oil). That objective has an adjustable aperture to permit darkfield.
The drum shaped diatoms (Coscinodiscus wailesii ... thanks Rene) in the second image are very large diatoms. That was taken in brightfield with a 10X objective (image cropped a fair amount).