INVESTIGADORES
FERNANDEZ SEVERINI Melisa Daiana
congresos y reuniones científicas
Título:
Plankton features vs environmental quality in the inner zone of Bahía Blanca Estuary (Argentina)
Autor/es:
HOFFMEYER MÓNICA SUSANA; BARRIA DE CAO MARÍA SONIA; BERASATEGUI ANABELA ANAHÍ; PETTIGROSSO ROSA; DUTTO MARÍA SOFÍA; LOPEZ ABBATE MARÍA CELESTE; BIANCALANA FLORENCIA; FULCO KARIN; FERNÁNDEZ SEVERINI MELISA DAIANA; MENÉNDEZ MARÍA CLARA; DIODATO SOLEDAD LORENA; BARNECH BIELSA GUADALUPE; CHAZARRETA CARLO JAVIER
Lugar:
Liverpool
Reunión:
Simposio; European Marine Biology Symposium 2009; 2009
Institución organizadora:
School of Biological Sciences, University of Liverpool
Resumen:
<!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;
mso-font-charset:0;
mso-generic-font-family:roman;
mso-font-pitch:variable;
mso-font-signature:-1610611985 1107304683 0 0 159 0;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;
mso-font-charset:0;
mso-generic-font-family:swiss;
mso-font-pitch:variable;
mso-font-signature:-1610611985 1073750139 0 0 159 0;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{mso-style-unhide:no;
mso-style-qformat:yes;
mso-style-parent:"";
margin-top:0cm;
margin-right:0cm;
margin-bottom:10.0pt;
margin-left:0cm;
line-height:115%;
mso-pagination:widow-orphan;
font-size:11.0pt;
font-family:"Calibri","sans-serif";
mso-fareast-font-family:"Times New Roman";
mso-bidi-font-family:"Times New Roman";
mso-ansi-language:EN-GB;
mso-fareast-language:EN-US;}
.MsoChpDefault
{mso-style-type:export-only;
mso-default-props:yes;
mso-ascii-font-family:Calibri;
mso-ascii-theme-font:minor-latin;
mso-fareast-font-family:Calibri;
mso-fareast-theme-font:minor-latin;
mso-hansi-font-family:Calibri;
mso-hansi-theme-font:minor-latin;
mso-bidi-font-family:"Times New Roman";
mso-bidi-theme-font:minor-bidi;
mso-fareast-language:EN-US;}
.MsoPapDefault
{mso-style-type:export-only;
margin-bottom:10.0pt;
line-height:115%;}
@page Section1
{size:612.0pt 792.0pt;
margin:70.85pt 3.0cm 70.85pt 3.0cm;
mso-header-margin:35.4pt;
mso-footer-margin:35.4pt;
mso-paper-source:0;}
div.Section1
{page:Section1;}
-->
The inner zone of
Bahía Blanca Estuary is associated with an intense industrial, maritime
activity and periodic dredging. A monthly biomonitoring has been carried out as
of 2006 in
order to determine a planktonic baseline in this area and establish ecological
indicators of system health. Environmental data as well as information on the
taxonomic composition, biomass, abundance and diversity of phyto, micro, meso-
and macrozooplankton were recorded along seven stations of the Principal
Channel in 2007. 53 phytoplanktonic taxa were found whereas 22 taxa of the
microzooplankton, were observed. 70 meso- macrozooplanktonic taxa were found.
Crustaceans were the dominant fraction, the copepods Acartia tonsa
(native) and Eurytemora americana (invader) being the dominant ones.
Mesozooplankton showed highest mean abundance and biomass values in summer and
ending winter. These values coincided with A. tonsa (6,232 ind m-3) and E.
americana (18,543 ind m-3) population peaks, the latter being the highest
than those recorded to date. Macrozooplankton was scarce and presented maximum
abundance and biomass in summer which coincided with the mysidacean Arthromysis
magellanica (212.24 ind m-3) population peak. Changes in the temporal and
spatial distribution of phyto- and microzooplankton composition which lead to
changes in the diversity values, were recorded with respect to data from
1996-1997 (Pettigrosso & Barría de Cao, 2007; Popovich, 2007). In
addition, variations in the temporal and spatial composition of micro-, meso-
and macrozooplankton, a higher abundance and biomass, and differences in
specific diversity were recorded in the present research with respect to those
mentioned historic data (Hoffmeyer, 1994; Hoffmeyer, 2004). Several ecological
processes must have been occurring in the studied biotic associations such as
changes in predation interactions as well as competition and perturbation of
niches (Pianka, 1982), which is evidenced by the recently observed changes in
the composition and in the abundance patterns. In addition, the effects of
acute pollution by toxic substances, in some punctual sites within this area,
could have influenced the spatial and temporal distribution. The use of
bio-ecological monitoring in aquatic ecosystems subjected to anthropogenic
pressure, such as rivers and coasts, has intensified since the 90s due to the
high sensitivity of the biotic community to respond with some advance to small
environmental changes of global or local type (Davis & Simon, 1995).
Determine the causes of the observed changes at a systemic level, is a complex
and difficult goal to achieve only from field data, mainly due to the likely
synergies between the different factors and processes. In this case, it would
be neccesary to add experimental works, through which to test hypotheses
arising from the observational data.