Sand bar opening in a coastal lagoon (Iquipari) in the northern region of Rio De Janeiro State: hydrological and hydrochemical changes.
نویسندگان
چکیده
The aim of this paper was to verify hydrological and hydrochemical changes in the Iquiparí Lagoon water column, during three months, as related to an artificial sand bar opening. A drastic reduction in water volume occurred 28 hours after the sand bar opening, exposing the bottom sediment. This was densely colonized by submerged aquatic plants, which were dominant in the ecosystem metabolism, specially near the sand bar. An increase in salinity values, and dissolved and total nutrient concentrations, was observed during the sand bar opening period. In contrast, chlorophyll a concentration decreased. These changes were associated with: 1) mix of remained brackish and marine waters; 2) nutrient release from sediments by physical processes; and 3) submerged plant death. After the sand bar closure, lagoon metabolism was completely regulated by a dense phytoplankton community. We observed that the sand bar opening resulted in an extensile replacement of the lagoon's water and a change in the community mainly responsible for the ecosystem metabolism.
منابع مشابه
Palynological evidence of the replacement of the hygrophilous forest by field vegetation during the last 7,000 years B.P. in the northern coast of Rio de Janeiro, Brazil.
Historians claim that European colonizers of the northern coast of Rio de Janeiro State found vast herbaceous fields when arrived in this region. Hypotheses about the origin of these fields include forest burning by the Goitacás indians and periodical floods by the Paraíba do Sul River and the lagoon system. The palynologycal analysis of two lake cores obtained in the municipality of Campos dos...
متن کاملScale to Assess Leaders' Perceptions about their Workers' Digital Addiction
Background: With the evolution of technologies and the mobility factor, new digital devices have emerged, influencing human behavior and provoking diverse dependencies due to their abusive use. Collective environments begin to exhibit the symptoms of such dependencies, compromising people's quality of life (QOL). The objective of the present study was to valida...
متن کاملSeasonal hydrochemical variation in a tropical coastal lagoon (Açu Lagoon, Brazil).
Hydrochemical conditions in the Açu Lagoon are described using spatial and temporal variations of various limnological variables (water temperature, dissolved oxygen, electric conductivity, total alkalinity, carbon dioxide, dissolved and total nutrients (N, P and Si), and chlorophyll a). Collected data was used in order to understand the structure and functioning of an enclosed coastal lagoon s...
متن کاملEnvironmental changes and zooplankton temporal and spatial variation in a disturbed Brazilian coastal lagoon.
The Imboassica lagoon, located in the Municipality of Macaé (RJ), is separated from the sea by a sand bar, and its surroundings are partially occupied by residential areas. This coastal lagoon has undergone environmental degradation due to sewage input and artificial sand bar openings. The temporal and spatial variation of environmental variables and zooplankton were studied monthly for four ye...
متن کاملA fuzzy approach to the evaluation of human factors in ultrasonic nondestructive examinations
Human factors are among the main elements affecting the reliability of nondestructive examinations (NDE). In a man-machine system, human reliability is affected by many factors (performance shaping factors) whose influence on reliability cannot be easily expressed quantitatively. This paper identifies and ranks 59 perform-ance shaping factors by using a fuzzy reasoning method and proposes a pro...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Brazilian journal of biology = Revista brasleira de biologia
دوره 62 1 شماره
صفحات -
تاریخ انتشار 2002