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Appearance and establishment of diazotrophic cyanobacteria in Lake Kinneret, Israel
Author(s) -
HADAS O.,
PINKAS R.,
MALINSKYRUSHANSKY N.,
NISHRI A.,
KAPLAN A.,
RIMMER A.,
SUKENIK A.
Publication year - 2012
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.2012.02792.x
Subject(s) - phytoplankton , cylindrospermopsis raciborskii , biology , nitrogen fixation , aphanizomenon , ecology , heterocyst , water column , cyanobacteria , subtropics , environmental science , anabaena , nutrient , nitrogenase , genetics , bacteria
Summary 1. We propose that the appearance and establishment of Nostocales (cyanobacteria) species of the genera Aphanizomenon and Cylindrospermopsis in the warm subtropical Lake Kinneret (Sea of Galilee, Israel) from 1994 was linked to changes in climate conditions and summer nitrogen (N) availability. 2. From 1994 to 2009, an increase in frequency of events of elevated water temperature (>29 °C) in summer, and to some extent a greater frequency of lower summer wind speed events, affected water turbulence and water column stratification, thus providing better physical conditions for the establishment of these populations. 3. In recent years, N‐depleted conditions in Lake Kinneret in early summer have promoted the development and domination of Nostocales that could gain an ecological advantage owing to their N 2 ‐fixing capability. 4. Nitrogen fixation rates coincided both with heterocyst abundance and with Nostocales biomass. The N supplied to the lake via nitrogen fixation ranged from negligible quantities when Nostocales represented only a minor component of the phytoplankton community to 123 tonnes when Cylindrospermopsis bloomed in 2005. This high N 2 fixation rate equals the average summer dissolved inorganic nitrogen load to the lake via the Jordan River.