Seasonal morphological variability in an in situ Cyanobacteria monoculture: example from a persistent Cylindrospermopsis bloom in Lake Catemaco, Veracruz, Mexico
Por:
Lind, Owen, Davalos-Lind, Laura, Lopez, Carlos, Lopez, Martin, Dyble Bressie, Juli
Publicada:
1 ene 2016
Resumen:
The phrase cyanobacteria bloom implies a transient condition in which
one to few species dominates communities. In this paper we describe a
condition in which the bloom is of multi-year duration consisting of
different morphologies of a single cyanobacteria species. Lake Catemaco,
Veracruz, Mexico maintained a year-round massive (108 trichomes L-1)
population of potentially toxin-producing cyanobacteria,
Cylindrospermopsis spp. The trichomes are present as straight and coiled
morphotypes. The relative trichome morphology abundance varied with
rainy (June-October) and dry seasons (November-May), but total trichome
abundance did not vary. Coiled trichomes and heterocytes (occurring only
on coiled trichomes) were significantly more abundant, both absolutely
and relatively, during the dry season. Both coiled trichome and
heterocyte mean volumes were significantly smaller during the rainy
season than during the dry season. Biovolumes were largest in January
when water temperature was 5 degrees C cooler suggesting buoyancy as a
morphology-determining factor. However, with a more than three-fold
lower TIN concentration during the dry season, we hypothesized that the
coiled morphotype became abundant primarily because it formed
heterocytes, which the straight morphotype did not. Spatial trichome and
heterocyte abundance differences were small among the 15 lake sites
(average CV for all dates: 20%). However, there was a pattern of
increased heterocyte and coiled trichome abundance from lake inflow, as
a nitrogen source, to outflow during the rainy season. The total volume
of heterocytes per litre of lake water increased progressively four-fold
from a minimum early in the rainy season to a maximum at the end of the
dry season. Morphological diversity, as seen in Lake Catemaco, can
partially compensate for the lack of species diversity in determination
of community structure.
Filiaciones:
Lind, Owen:
Baylor Univ, Ctr Reservoir & Aquat Syst Res, Waco, TX 76798 USA
Baylor Univ, Dept Biol, Waco, TX 76798 USA
Davalos-Lind, Laura:
Baylor Univ, Ctr Reservoir & Aquat Syst Res, Waco, TX 76798 USA
Baylor Univ, Dept Biol, Waco, TX 76798 USA
Lopez, Carlos:
Univ Zulia, Dept Biol, Zooplankton Lab, Maracaibo 4011, Venezuela
Lopez, Martin:
Univ Nacl Autonoma Mexico, Lab Marine Pollut, Inst Marine Sci & Limnol, Circuito Exterior S-N,Ciudad Univ, Mexico City 04510, DF, Mexico
Dyble Bressie, Juli:
NOAA, NW Fisheries Sci Ctr, 2725 Montlake Blvd E, Seattle, WA 98112 USA
All Open Access, Gold
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