Aureoumbra lagunensis

Aureoumbra lagunensis
Scientific classification Edit this classification
Domain: Eukaryota
Clade: Diaphoretickes
Clade: SAR
Clade: Stramenopiles
Phylum: Gyrista
Subphylum: Ochrophytina
Class: Dictyochophyceae
Order: Sarcinochrysidales
Family: Sarcinochrysidaceae
Genus: Aureoumbra
Species:
A. lagunensis
Binomial name
Aureoumbra lagunensis
D.A.Stockwell, DeYoe, Hargraves & P.W.Johnson

Aureoumbra lagunensis is a unicellular planktonic marine microalga that belongs in the genus Aureoumbra under the class Pelagophyceae.[1] It is similar in morphology and pigments to Aureococcus anophagefferens and Pelagococcus subviridis.[2] The cell shape is spherical to subspherical and is 2.5 to 5.0 μm in diameter.[1] It is golden-coloured and is encapsulated with extracellular polysaccharide layers and has a single chloroplast structure with pigments.[1]

Aureoumbra lagunensis thrives in a warm hypersaline environment as the greatest cell density has been found in water with salinity higher than 40 PSU and with temperatures between 25–30 °C (77–86 °F).[2] Generally, the density of A. lagunensis is in the order of 106 cells mL−1, being higher in the summer months with lower abundance during the winter.[2]

Aureoumbra lagunensis causes harmful algal blooms and was the dominant microalga in the 7 year long brown tide (1990 - 1997) that happened in Laguna Madre, Texas.[3] Its dominance over other coexisting phytoplankton is in part associated with its encapsulating mucus layer of exopolymer secretions (EPS) and its ability to revert from vegetative and resting cell forms.[3][4] The A. lagunensis blooms cause a substantial increase in light attenuation, which in turn contributes to marine biodiversity loss, particularly phytoplankton communities and benthic invertebrates. A. lagunensis thrives in low-light conditions, where it can maintain high growth rates at 150 umol photons m−2 s−1,[5] thus an increase in light attenuation causes a positive feedback which further perpetuates blooms.

Aureoumbra lagunensis nutrient uptake is unlike other common microalgae. It uptakes inorganic nitrogen in the form of ammonium (NH4+) and nitrite (NO2−) and organic nitrogen in the form of urea, but does not utilize nitrate (NO3−).[2][6][7][8] It uses environment dissolved organic phosphorus as the sole source to regenerate phosphate for growth.[9]

  1. ^ a b c DeYoe, Hudson R.; Stockwell, Dean A.; Bidigare, Robert R.; Latasa, Mikel; Johnson, Paul W.; Hargraves, Paul E.; Suttle, Curtis A. (December 1997). "Description and Characterization of the Algal Species Aureoumbra Lagunensis Gen. et Sp. Nov. and Referral of Aureoumbra and Aureococcus to the Pelagophyceae". Journal of Phycology. 33 (6): 1042–1048. doi:10.1111/j.0022-3646.1997.01042.x. ISSN 0022-3646. S2CID 86479200.
  2. ^ a b c d Cite error: The named reference :7 was invoked but never defined (see the help page).
  3. ^ a b Liu, Hongbin; Buskey, Edward J. (2000). "The exopolymer secretions (EPS) layer surrounding Aureoumbra lagunensis cells affects growth, grazing, and behavior of protozoa". Limnology and Oceanography. 45 (5): 1187–1191. Bibcode:2000LimOc..45.1187L. doi:10.4319/lo.2000.45.5.1187. ISSN 1939-5590. JSTOR 2670711.
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  9. ^ Sun, Ming-Ming; Sun, Jin; Qiu, Jian-Wen; Jing, Hongmei; Liu, Hongbin (2012-03-15). "Characterization of the Proteomic Profiles of the Brown Tide Alga Aureoumbra lagunensis under Phosphate- and Nitrogen-Limiting Conditions and of Its Phosphate Limitation-Specific Protein with Alkaline Phosphatase Activity". Appl. Environ. Microbiol. 78 (6): 2025–2033. doi:10.1128/AEM.05755-11. ISSN 0099-2240. PMC 3298125. PMID 22247172.