Thalassiosira baltica
Ostenfeld, 1901
Common Name:
A centric diatom
Synonyms and Other Names:
Coscinodiscus polyacanthus var. balticus Grunow, 1880, Coscinodiscus balticus Grunow ex Cleve, 1891, Coscinodiscus subtilis var. fluviatilis Lemmermann, 1904
Identification:
This cylindrical diatom displays flat or somewhat concave valves that form chains via long connecting threads. There may be 2–5 marginal labiate processes between the valve face and the mantle, 4–6 central pore-like fultoportulae on the valve face, and generally 2 rings of fultoportulae on the mantle. Areolae are loculate, often hexagon-shaped, and arranged in radial rows. Silicification may vary from population to population (Edlund et al. 2000, Hasle 1978, Hasle and Syvertsen 1990).The diameter of T. baltica in Lake Ontario is around 16–27 µm but may be as great as 120 µm in other regions. Diameter could be inversely related to salt content in water (Edlund et al. 2000, Hasle 1978).
Size:
diameter <120 microns, smaller in Great Lakes
Native Range:
Exact native range is unclear. The type locality is the Baltic Sea and a large number of records exist from this sea, polar seas, inland Eurasian seas, and many parts of coastal Europe. Thalassiosira baltica has also been recorded off the coasts of Japan and the western United States (Edlund et al. 2000, Hasle 1978, Hasle and Syvertsen 1990).
|
|
|
This map only depicts Great Lakes introductions.
|
|
Great Lakes Nonindigenous Occurrences:
Thalassiosira baltica was first recorded in sediment cores from Lake Ontario around 1988 (Edlund et al. 2000). It has since been recorded in Lake Erie and Lake Superior (US EPA 2008).
Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Thalassiosira baltica are found here.
Table last updated 5/1/2024
† Populations may not be currently present.
Ecology:
Thalassiosira baltica is a euryhaline species that grows rapidly and often occurs in areas experiencing anthropogenic impacts. It may form resting cells that could survive dark, anoxic conditions. It can very likely tolerate ballast water exchange, as it has survived conditions with conductivity as low as 300 µmho/cm in Lake Ontario and salinity as high as 44‰ in other regions of the world. Growth rates reach a maximum at salinities around 4–8‰, but growth at 80% or more of the maximum rate has still been recorded at salinities varying from 0.5–20‰. Below a salinity of 2‰, growth may vary depending on the exact ionic composition of water in which populations occur. In the Baltic and Arctic Seas, T. baltica occurs most abundantly in areas influenced by large Canadian and Siberian rivers or other regions of relatively low salinity. It typically does not occur in regions of relatively high salinity such as the Oslofjord. Thalassiosira baltica is consumed by copepods and its skeleton may remain completely intact in fecal pellets. Thalassiosira baltica settles out of the water column much faster in fecal pellets than when it is not consumed (Hasle and Syvertsen 1990, Paasche 1975, Schrader 1971).
Means of Introduction:
Thalassiosira baltica was very likely introduced water to the Great Lakes basin in ballast (Edlund et al. 2000).
Status:
Established where recorded.
Great Lakes Impacts:
Summary of species impacts derived from literature review. Click on an icon to find out more...
There is little or no evidence to support that Thalassiosira baltica has significant environmental impacts in the Great Lakes.
Realized:
The introduction and establishment of T. baltica were accompanied by the extirpation of the native diatom Stephanodiscus niagarae in Lake Ontario, both estimated as occurring around 1988 (Edlund et al. 2000, Julius et al. 1998). It is not clear whether T. baltica caused this local extinction or if lake change or another biological explanation (e.g., silica limitation inhibiting sexual reproduction in S. niagarae) drove the observed species turnover (Edlund et al. 2000).
There is little or no evidence to support that Thalassiosira baltica has significant socio-economic impacts in the Great Lakes.
There is little or no evidence to support that Thalassiosira baltica has significant beneficial effects in the Great Lakes.
Management:
Regulations (pertaining to the Great Lakes region)
There are no known regulations for this species.
Note: Check federal, state/provincial, and local regulations for the most up-to-date information.
Control
Biological
There are no known biological control methods for this species.
Physical
There are no known physical control methods for this species
Chemical
There are no known chemical control methods for this species.
Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.
Remarks:
Thalassirosira baltica may be synonymous with T. subsalina from the Baltic Sea. The two may or may not be one species that varies morphologically with changing salinity (Hasle 1978).
References
(click for full reference list)
Author:
Kipp, R.M., M. McCarthy, and A. Fusaro
Contributing Agencies:
Revision Date:
9/12/2019
Citation for this information:
Kipp, R.M., M. McCarthy, and A. Fusaro, 2024, Thalassiosira baltica Ostenfeld, 1901: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI, https://nas.er.usgs.gov/queries/greatLakes/FactSheet.aspx?Species_ID=2717&Potential=N&Type=0&HUCNumber=DGreatLakes, Revision Date: 9/12/2019, Access Date: 5/1/2024
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.