191
14
Phytoplankton Assemblages as an
Indicator of Water Quality in Seven
Temperate Estuarine Lakes
in South-East Australia
Dongyan Liu, R. J. Morrison and R. J. West
R. J. Morrison () · D. Liu · R. J. West
School of Earth and Environmental Sciences,
University of Wollongong, 2522 Wollongong, NSW, Australia
e-mail: johnm@uow.edu.au
D. Liu
Yantai Institute of Coastal Zone Research, Chinese Academy of
Sciences, 264003 Yantai, Shandong Province, Pepole’s Republic
China
Abstract
Phytoplankton species diversity and their ecological characteristics in seven coastal estuaries of different eutrophication status in southeast Australia were described. Seasonal patterns in physical and chemical properties of the waters were assessed over 2 years, along
with chlorophyll a data and phytoplankton numbers and diversity. It was found that the
phytoplankton species composition and biomass pattern reflected the characteristics of temperature, salinity, nutrients, and habitat in the studied estuaries. A total of 145 species were
identified in the different lakes with Diatom and Dinoflagellete species being the main
contributors to phytoplankton diversity. Seasonal patterns of phytoplankton assemblages
showed that maxima occurred in winter or spring, being mainly affected by temperature
and nutrient availability. The eutrophic indicative signals of the phytoplankton species distributions appear to be diminished by the presence of large seagrass beds and extensive
macroalgae growth.
Keywords
Eutrophication · Estuaries · Phytoplankton
14.1 Introduction
There are more than 130 estuaries in New South Wales
(NSW), Australia, with about 50 % of them considered as
Intermittently Closed and Open Lakes or Lagoons (ICOLLs)
(Roy et al. 2001). These ICOLLs range from small mostly
closed lagoons to large open lakes and are very important
catchments for local (recreation) and fish nursery. Over recent decades, urbanization, habitat modification, population
growth, and agriculture have significantly influenced the
ecosystems of these estuaries, e.g., about 17 % of mangroves
and 21 % of saltmarshes have been lost since European settlement (Turner et al. 2004). Moreover, the water quality of
estuaries near the large population centers has been deteriorating owing to rising nutrient levels and other chemical pollutants (Scanes et al. 2007).
Phytoplankton can be greatly impacted by environmental change, especially increases in nutrients, and microalgal
blooms have been widely observed in Australian estuaries
and reported by scientists and governments over the past two
decades (e.g., Ajani et al. 2001, 2002). Little information is
available, however, on phytoplankton assemblages in the estuaries of NSW and such information has therefore not been
commonly used in the assessment of water quality. Thus, a
comprehensive understanding of the phytoplankton communities including species composition, biomass and seasonal
patterns, is urgently required for improving the environmental management of the estuaries of NSW.
In contrast to coastal rivers and embayments, which have
free exchange with ocean waters, only limited research
A. A. Ansari, S. S. Gill (eds.), Eutrophication: Causes, Consequences and Control,
DOI 10.1007/978-94-007-7814-6_14, © Springer Science+Business Media Dordrecht 2014
14
Phytoplankton Assemblages as an
Indicator of Water Quality in Seven
Temperate Estuarine Lakes
in South-East Australia
Dongyan Liu, R. J. Morrison and R. J. West
R. J. Morrison () · D. Liu · R. J. West
School of Earth and Environmental Sciences,
University of Wollongong, 2522 Wollongong, NSW, Australia
e-mail: johnm@uow.edu.au
D. Liu
Yantai Institute of Coastal Zone Research, Chinese Academy of
Sciences, 264003 Yantai, Shandong Province, Pepole’s Republic
China
Abstract
Phytoplankton species diversity and their ecological characteristics in seven coastal estuaries of different eutrophication status in southeast Australia were described. Seasonal patterns in physical and chemical properties of the waters were assessed over 2 years, along
with chlorophyll a data and phytoplankton numbers and diversity. It was found that the
phytoplankton species composition and biomass pattern reflected the characteristics of temperature, salinity, nutrients, and habitat in the studied estuaries. A total of 145 species were
identified in the different lakes with Diatom and Dinoflagellete species being the main
contributors to phytoplankton diversity. Seasonal patterns of phytoplankton assemblages
showed that maxima occurred in winter or spring, being mainly affected by temperature
and nutrient availability. The eutrophic indicative signals of the phytoplankton species distributions appear to be diminished by the presence of large seagrass beds and extensive
macroalgae growth.
Keywords
Eutrophication · Estuaries · Phytoplankton
14.1 Introduction
There are more than 130 estuaries in New South Wales
(NSW), Australia, with about 50 % of them considered as
Intermittently Closed and Open Lakes or Lagoons (ICOLLs)
(Roy et al. 2001). These ICOLLs range from small mostly
closed lagoons to large open lakes and are very important
catchments for local (recreation) and fish nursery. Over recent decades, urbanization, habitat modification, population
growth, and agriculture have significantly influenced the
ecosystems of these estuaries, e.g., about 17 % of mangroves
and 21 % of saltmarshes have been lost since European settlement (Turner et al. 2004). Moreover, the water quality of
estuaries near the large population centers has been deteriorating owing to rising nutrient levels and other chemical pollutants (Scanes et al. 2007).
Phytoplankton can be greatly impacted by environmental change, especially increases in nutrients, and microalgal
blooms have been widely observed in Australian estuaries
and reported by scientists and governments over the past two
decades (e.g., Ajani et al. 2001, 2002). Little information is
available, however, on phytoplankton assemblages in the estuaries of NSW and such information has therefore not been
commonly used in the assessment of water quality. Thus, a
comprehensive understanding of the phytoplankton communities including species composition, biomass and seasonal
patterns, is urgently required for improving the environmental management of the estuaries of NSW.
In contrast to coastal rivers and embayments, which have
free exchange with ocean waters, only limited research
A. A. Ansari, S. S. Gill (eds.), Eutrophication: Causes, Consequences and Control,
DOI 10.1007/978-94-007-7814-6_14, © Springer Science+Business Media Dordrecht 2014