1 Introduction
Bacteria play a vital role in every ecosystem. They reflect rapidly the changes in
environment due to their short multiplication time. Because bacterial cells surface is
relatively large compared to their volume, microorganisms produce significant
amounts of carbon dioxide by their respiration and therefore influence CO 2 concentrations in the hydrosphere and, indirectly, in the atmosphere. Together with
phytoplankton, microorganisms are responsible for the carbon cycle in freshwater
and marine ecosystems (Hoppe et al. 2002). They are supporting not only the organic
matter decay and mineralization, but also contribute to feeding the higher levels of
trophic chains (so called microbial loop) (Azam et al. 1983; Pomeroy 1974) by
incorporating the dissolved organic matter (DOM) into the trophic web. This activity
of recycling the nutrients is recognized as the basic process providing proper Arctic
marine ecosystems functioning (Nielsen and Hansen 1999; Iversen and Seuthe 2011;
Lara et al. 2013). DOM of the land origin is used by microorganisms as the energy
source in coastal and estuary areas (Zweifel and Hagstrom 1995; Moran and Hodson
1994). The main sources of bacteria nourishment are substances produced during
organic matter and feces decay (Lampert 1978; Elbrächter 1991; Nagata and Kirchman 1992), as well as leftovers of zooplankton sloppy feeding and substances
secreted by phytoplankton (Sharp 1977; Obernosterer and Herndl 1995). Availability of substrates and water temperature influence bacterial growth rates, when
bacteriovorus and bacteriophages regulate the bacteria number and their biomass
(Thingstad and Sakshaug 1990; Payet and Suttle 2008). Bacteria may live floating in
the water as a single cells or in consortia on some solid particles; therefore the
presence of particulate inorganic matter (PIM) creates a favourable habitat for larger
colonies. Typical values of TBN in polar marine ecosystems usually vary between
several thousands up to a few millions of cells in 1 cm
3 (Table 1).
Research in the Arctic region were limited in the past because of the access
difficulties, but in recent decades polar region gained growing concern. Fjords of
western Spitsbergen are one of the best explored arctic marine ecosystems, however
microbial part of their biocenosis is still not so well known. In the past, bacterial
abundance and biomass were investigated mostly in Kongsfjorden (Iversen and
Seuthe 2011; Wängberg et al. 2008; Jankowska et al. 2005; Jiang et al. 2005). Also
other detailed microbiological research were done in Kongsfjorden: isolation of
cultivable bacteria (Prasad et al. 2014) and studying of microbial communities
composition by the molecular methods (Piquet et al. 2010; Zeng et al. 2013).
Hornsund is a less explored region—in 1985 the microbiological study was initiated by Zajączkowska and Zajączkowski (1989). Recently, single colony isolates
from sediments were done by Rasol et al. (2014).
In this study the research of basic microbiological parameters was done to
compare marine ecosystems of Hornsund and Kongsfjorden during the same
summer. The purpose was to study the abundances, biomass and distribution of
bacterial assemblages in the area of two arctic fjords. Also the relations with the
physical water parameters was analyzed.
116
A. Kalinowska et al.
Bacteria play a vital role in every ecosystem. They reflect rapidly the changes in
environment due to their short multiplication time. Because bacterial cells surface is
relatively large compared to their volume, microorganisms produce significant
amounts of carbon dioxide by their respiration and therefore influence CO 2 concentrations in the hydrosphere and, indirectly, in the atmosphere. Together with
phytoplankton, microorganisms are responsible for the carbon cycle in freshwater
and marine ecosystems (Hoppe et al. 2002). They are supporting not only the organic
matter decay and mineralization, but also contribute to feeding the higher levels of
trophic chains (so called microbial loop) (Azam et al. 1983; Pomeroy 1974) by
incorporating the dissolved organic matter (DOM) into the trophic web. This activity
of recycling the nutrients is recognized as the basic process providing proper Arctic
marine ecosystems functioning (Nielsen and Hansen 1999; Iversen and Seuthe 2011;
Lara et al. 2013). DOM of the land origin is used by microorganisms as the energy
source in coastal and estuary areas (Zweifel and Hagstrom 1995; Moran and Hodson
1994). The main sources of bacteria nourishment are substances produced during
organic matter and feces decay (Lampert 1978; Elbrächter 1991; Nagata and Kirchman 1992), as well as leftovers of zooplankton sloppy feeding and substances
secreted by phytoplankton (Sharp 1977; Obernosterer and Herndl 1995). Availability of substrates and water temperature influence bacterial growth rates, when
bacteriovorus and bacteriophages regulate the bacteria number and their biomass
(Thingstad and Sakshaug 1990; Payet and Suttle 2008). Bacteria may live floating in
the water as a single cells or in consortia on some solid particles; therefore the
presence of particulate inorganic matter (PIM) creates a favourable habitat for larger
colonies. Typical values of TBN in polar marine ecosystems usually vary between
several thousands up to a few millions of cells in 1 cm
3 (Table 1).
Research in the Arctic region were limited in the past because of the access
difficulties, but in recent decades polar region gained growing concern. Fjords of
western Spitsbergen are one of the best explored arctic marine ecosystems, however
microbial part of their biocenosis is still not so well known. In the past, bacterial
abundance and biomass were investigated mostly in Kongsfjorden (Iversen and
Seuthe 2011; Wängberg et al. 2008; Jankowska et al. 2005; Jiang et al. 2005). Also
other detailed microbiological research were done in Kongsfjorden: isolation of
cultivable bacteria (Prasad et al. 2014) and studying of microbial communities
composition by the molecular methods (Piquet et al. 2010; Zeng et al. 2013).
Hornsund is a less explored region—in 1985 the microbiological study was initiated by Zajączkowska and Zajączkowski (1989). Recently, single colony isolates
from sediments were done by Rasol et al. (2014).
In this study the research of basic microbiological parameters was done to
compare marine ecosystems of Hornsund and Kongsfjorden during the same
summer. The purpose was to study the abundances, biomass and distribution of
bacterial assemblages in the area of two arctic fjords. Also the relations with the
physical water parameters was analyzed.
116
A. Kalinowska et al.