Spelling suggestions: "subject:"benthic"" "subject:"enthic""
271 |
Παρακολούθηση της οικολογικής ποιότητας των λιμνοθαλασσών Κοτύχι & Πρόκοπος της Δ. Ελλάδας : ανάλυση των βιοκοινωνιών των υδρόβιων μακρόφυτων και μακροασπόνδυλων στα πλαίσια εφαρμογής της οδηγίας 2000/60/ΕΕ για τα ύδαταΦυττής, Γεώργιος 05 July 2012 (has links)
Τα υδρόβια μακρόφυτα και τα βενθικά μακροασπόνδυλα μελετήθηκαν εποχικά σε δύο λιμνοθάλασσες της Δυτικής Ελλάδας (Κοτύχι και Πρόκοπος), με σκοπό την ανάλυση της χωρικής και εποχικής διακύμανσης των βιοκοινωνιών τους. Η λιμνοθάλασσα Κοτύχι παρουσιάζει μεγαλύτερη επικοινωνία με τη θάλασσα, ενώ ο Πρόκοπος έχει μεγαλύτερο βαθμό απομόνωσης από τη θάλασσα.
Τα υδρόβια μακρόφυτα αποτελούν κύριο στοιχείο των λιμνοθαλασσών. Συνολικά και στις δύο περιοχές μελέτης βρέθηκαν 22 taxa μακροφύτων (αγγειόσπερμα και μακροφύκη), εκ των οποίων τα 8 αποτελούν νέες αναφορές για την περιοχή μελέτης. Συγκεκριμένα, βρέθηκαν 16 taxa στο Κοτύχι (2 ροδοφύκη, 8 χλωροφύκη, 5 αγγειόσπερμα, 1 στρεπτόφυτο) και 14 στον Πρόκοπο (1 ροδοφύκος, 5 χλωροφύκη, 5 αγγειόσπερμα, 3 στρεπτόφυτα). Τα αγγειόσπερμα Ruppia cirrhosa και Potamogeton pectinatus ήταν κυρίαρχα και στις δύο λιμνοθάλασσες. Κυρίαρχο taxon στο Κοτύχι ήταν και το χλωροφύκος Cladophora glomerata, ενώ για τον Πρόκοπο το αγγειόσπερμο Zannichellia pallustris ssp. pedicellata. H βιομάζα των υδρόβιων μακροφύτων παρουσίασε μεγάλη αύξηση κατά τη διάρκεια της θερινής περιόδου.
Στο Κοτύχι απαντούν 28 taxa υδροβίων μακροασπονδύλων, ενώ στον Πρόκοπο 19. Η οικογένεια των Chironomidae (Miscellanea) και το Lekanesphaera monodi (Καρκινοειδή) ήταν τα κυρίαρχα taxa και για τις δύο λιμνοθάλασσες. Η ποικιλότητα (Η’) της βενθικής πανίδας κυμάνθηκε από 1,3 έως 2,6 στο Κοτύχι και από 0,7 έως 2,4 στον Πρόκοπο.
Τα αποτελέσματα της ιεραρχικής ομαδοποίησης (Cluster analysis) σε σύνολο 72 δειγματοληπτικών επιφανειών, με βάση την αφθονία των υδρόβιων μακροφύτων στις δύο περιοχές μελέτης, ανέδειξαν 5 ομάδες βλάστησης. Στην ομάδα Ι κυρίαρχο taxon είναι το αγγειόσπερμο Zostera noltii, ενώ στις ομάδες ΙΙa και ΙΙb κυριαρχεί το αγγειόσπεrμο Ruppia cirrhosa, με διαφορετική αντιπροσώπευση των συνοδών ειδών. Στην ομάδα ΙΙIa κυριαρχούν τα αγγειόσπερμα Potamogeton pectinatus και Zannichellia pallustris ssp. pedicellata, ενώ η ομάδα ΙΙIb κυριαρχείται από το Zannichellia pallustris ssp. pedicellata που συνοδεύεται από το χλωροφύκος Ulva intestinalis. O έλεγχος των διαφορών των ομάδων βλάστησης, με βάση τη διακύμανση των περιβαλλοντικών τους παραμέτρων πραγματοποιήθηκε με τον έλεγχο Mann - Whitney U. Στατιστικά σημαντικές διαφορές υπάρχουν μεταξύ της ομάδας ΙΙb με τις ομάδες Ι και ΙΙIb, όσον αφορά το βάθος και μεταξύ της ομάδας ΙΙb και ΙΙΙa, όσον αφορά την αναλογία διαφάνεια/βάθος και τη συγκέντρωση του ολικού φωσφόρου.
Τα αποτελέσματα της ιεραρχικής ομαδοποίησης (Cluster analysis) σε σύνολο 36 δειγματοληπτικών επιφανειών, με βάση την αφθονία των υδρόβιων μακροασπονδύλων ανέδειξαν δύο ομάδες βενθικής πανίδας σε επίπεδο ομοιότητας περίπου 50% (Bray curtis similarity 50%) που αντιστοιχούν στις δύο λιμνοθάλασσες. Η ομάδα που αντιστοιχεί στο Κοτύχι κυριαρχείται από την οικογένεια Chironomidae και η ομάδα που αντιστοιχεί στον Πρόκοπο κυριαρχείται από την οικογένεια Οstracoda.
O έλεγχος Mann - Whitney U έδειξε ότι οι δύο λιμνοθάλασσες διαφέρουν με βάση τις αβιοτικές παραμέτρους σε επίπεδο σημαντικότητας p<0,001 στο βάθος, την αναλογία διαφάνεια/βάθος, τη συγκέντρωση του ολικού φωσφόρου, χλωροφύλλης –α και ολικών αιωρούμενων στερεών. Ο Πρόκοπος παρουσίασε μεγαλύτερο βάθος (0,87m) από το Κοτύχι (0,56m) και μεγαλύτερη διακύμανση των παραπάνω παραμέτρων. Γενικά, τα αποτελέσματα της ανάλυσης κύριων συνιστωσών (PCA) και της ανάλυσης ANOSIM, που αφορούν τις περιβαλλοντικές παραμέτρους έδειξαν ότι η διακύμανση των περιβαλλοντικών παραμέτρων παρουσίασε εποχικό και χωρικό πρότυπο και στις δύο λιμνοθάλασσες με τη μεγαλύτερη διακύμανση τους να παρατηρείται στον Πρόκοπo. Κατά τη διάρκεια της θερινής περιόδου ειδικά στον Πρόκοπο καταγράφηκαν πολύ χαμηλές τιμές διαλυμένου οξυγόνου (χαμηλότερη τιμή: 0,34 mg/l), ακραίες τιμές αλατότητας (μέγιστη τιμή: 38,43 psu) και αυξημένες τιμές pH (μέγιστη τιμή: 9,95). Αυτή η εποχική διακύμανση των περιβαλλοντικών παραμέτρων προκαλεί έντονο φυσικό στρες στους υδρόβιους οργανισμούς επηρεάζοντας την αφθονία και εξάπλωση τους.
Οι κυριότερες συσχετίσεις των αβιοτικών παραμέτρων που προέκυψαν από την ανάλυση Spearman είναι η θετική συσχέτιση του ολικού φώσφορου με τη χλωροφύλλη – α, τα ολικά αιωρούμενα στερεά και τη σταθερά απορρόφησης – α, η αρνητική συσχέτιση της αναλογίας διαφάνειας/βάθος με τον ολικό φώσφορο και τη χλωροφύλλη – α και του διαλυμένου οξυγόνου στο υπόστρωμα με τη συγκέντρωση φωσφορικών ιόντων, ολικού αζώτου, ολικού άνθρακα και οργανικού άνθρακα στο ίζημα.
Σύμφωνα με τα αποτελέσματα της ανάλυσης πλεονασμού (RDA), τo pH, η συγκέντρωση των ολικών αιωρούμενων στερεών της χλωροφύλλης - α, το βάθος, η θερμοκρασία και η σταθερά απορρόφησης Κ φαίνεται να παίζουν τον πιο σημαντικό ρόλο στην εξάπλωση & αφθονία των μακροφύτων. Όσον αφορά την εξάπλωση και αφθονία των υδρόβιων μακροασπονδύλων, σύμφωνα με την ανάλυση πλεονασμού (RDA), πιο σημαντικό ρόλο φαίνεται να παίζουν το βάθος, η συγκέντρωση των ολικών αιωρούμενων σωματιδίων, η θερμοκρασία και το pH.
Γενικά, στις δύο λιμνοθάλασσες καταγράφηκε χαμηλός ειδών μακροφύτων και μακροαπονδύλων, όπως και σε άλλες λιμνοθάλασσες της Ελλάδας (Reizopoulou and Nicolaidou 2004, Kevrekidis 2004, Mogias and Kevrekidis 2005). Ο χαμηλότερος αριθμός ειδών και ατόμων μακροασπονδύλων παρατηρήθηκε κατά τη διάρκεια της θερινής περιόδου. Τα αποτελέσματα έδειξαν επίσης ότι ο αριθμός ειδών, η ποικιλότητα και η αφθονία, των βενθικών μακροασπονδύλων σχετίζεται ισχυρά με την υδρόβια βλάστηση και το βαθμό απομόνωσης από τη θάλασσα. Ο αριθμός ειδών και ατόμων μακροασπονδύλων παρουσιάστηκε αυξημένος στον τύπο ενδιαιτήματος, όπου κυριαρχούν τα αγγειόσπερμα, ενώ παρουσιάστηκε μειωμένος σε γυμνό υπόστρωμα. Επίσης, ο αριθμός ειδών και ατόμων μακροασπονδύλων εμφανίζεται μειωμένος με την αύξηση της απόστασης από τη θάλασσα.
Τα αποτελέσματα της ανάλυσης πλεονασμού (RDA) έδειξαν ότι τα μαλάκια παρουσιάζουν καλύτερη συσχέτιση με το αγγειόσπερμο Zostera noltii και τα συνοδά του είδη, ενώ τα καρκινοείδη παρουσιάζουν καλύτερη συσχέτιση με τα αγγειόσπερμα Ruppia cirrhosa, Potamogeton pectinatus και Zannichellia pallustris ssp. pedicellata και τα συνοδά τους είδη. Τα Miscellanea δείχνουν καλύτερη συσχέτιση με τα ευκαιριακά είδη υδροβίων μακροφύτων. Το Gammarus insensibilis παρουσίασε συνεμφάνιση με το χλωροφύκος Chaetomorpha linum, το οποίο αποτελεί μέρος της διατροφής του (Sheader & Sheader 1987, Bamber et al. 1992).
Στην παρούσα εργασία συζητούνται περαιτέρω η οικολογική ποιότητα των δύο λιμνοθαλασσών και οι χωρικές και χρονικές διακυμάνσεις των περιβαλλοντικών παραμέτρων καθώς και οι επιδράσεις τους στη δομή και λειτουργία των βιοκοινωνιών των μακροφύτων και μακροασπονδύλων. / Aquatic macrophytes and benthic macroinvertebrates were studied seasonally in two coastal lagoons (Kotychi and Prokopos) located in Western Greece, in order to investigate spatial and temporal trends. Kotychi lagoon presents a better communication with the sea, while Prokopos has a high degree of confinement. Both ecosystems receive seasonally freshwater input by streams.
The submerged aquatic macrophytes constituted a major component of the ecosystems studied. In total were found 22 taxa of aquatic macrophytes (angiosperms and macroalgae), 16 taxa for Kotychi (2 Rhodophyta, 8 Chlorophyta, 5 Magnoliophyta, 1 Streptophyta) and 14 taxa for Prokopos (1 Rhodophyta, 5 Chlorophyta, 5 Magnoliophyta, 3 Streptophyta). Ruppia cirrhosa, and Potamogeton pectinatus were dominant in both lagoons. Kotychi lagoon was also dominated by Cladophora glomerata and Prokopos by Zannichellia pallustris ssp. pedicellata, while the biomass of aquatic species peaked during summer period.
The total number of macroinvertebrates found in the lagoons was 28 taxa for Kotychi and 19 for Prokopos. Chironomidae (Miscellanea) and Lekanesphaera monodi (Crustacea) were dominant in both lagoons, while Kotychi was also dominated by Monocorophium insidiosum (Crustacea), and Prokopos by Ostracoda (Crustacea). Benthic diversity (Η’) ranged from 1.3 to 2.6 in Kotychi and from 0.7 to 2.5 in Prokopos.
Cluster analysis (Bray Curtis similarity) distinguished 5 vegetation groups based on 72 sampling plots. Group I, was dominated by Zostera noltii, groups IIa and IIb were both dominated by Ruppia cirrhosa, but they present different abundance in companion opportunistic species. Group IIIa was dominated by Potamogeton pectinatus and Zannichellia pallustris ssp. pedicellata and group IIIb by Zannichellia pallustris ssp. pedicellata and Ulva intestinalis. Mann - Whitney U – test showed that means of environmental variables such as depth, total P and the ratio transparency/depth differed significantly among groups IIb, IIIa and IIIb.
Cluster analysis (Bray Curtis similarity) distinguished two groups of macroinvertebrates, based on 36 sampling plots. Group I represents Kotychi lagoon by Chironomidae and group II represents Prokopos lagoon II dominated by Ostracoda.
Mann - Whitney U – test showed that means of environmental variables such as depth, the ratio transparency/depth, total P, chl-a and TSM differed significantly between the two lagoons. Prokopos (0,87m) is a deeper lagoon than Kotychi (0,56m) and presented higher values of the ratio transparency/depth, total P, chl-a and TSM. Generally, PCA and ANOSIM analysis showed that there is a seasonal and spatial fluctuation of environmental variables in the two lagoons. Prokopos showed widest range of the environmental variables among seasons. In Prokopos lagoon during summer period recorded very low values of D.O. (lowest value: 0,34 mg/l), high salinity (max. value: 38,43 psu) and pH (max. value: 9,95). The high seasonal fluctuations of environmental variables create a natural stress to aquatic organisms affecting their abundance.
The results of Spearman analysis showed that total P was positively correlated with chl-a, TSM and attenuation coefficient K and the ratio transparency/depth was negatively correlated with total P and chl-a. Also, sediment’s D.O. was negatively correlated with orthophosphates, total nitrogen, total and organic carbon in the sediment. The results of RDA analysis showed that pH, TSM, chl-a, depth, attenuation coefficient K and temperature play the most important role in the abundance and distribution of aquatic macrophytes. Depth, TSM, temperature and pH influence the distribution and abundance of benthic mavroinvertebrates.
Generally, both lagoon showed low number of species of macrophytes and macroinvertebrates, similarly with other Greek lagoons (Reizopoulou and Nicolaidou 2004, Kevrekidis 2004, Mogias and Kevrekidis 2005). The lowest number of species and individuals of macroinvertebrates was recorded during the summer period. Moreover, results showed that species richness, diversity, and abundance of benthic macroinvertebrates were strongly related to aquatic vegetation and degree of confinement. The number of species and individuals of macroinvertebrates increased in the habitat where angiosperms were the dominated macrophytes. On the other hand, the number of species and individuals of macroinvertebrates presented lower values in bare substrates. Also, the number of species and individuals of macroinvertebrates presented a reduction at the sampling stations which have a high distance from the sea, in both lagoons.
RDA analysis showed that Mollusca prefer as a habitat the angiosperm Zostera noltii and its companion species. Crustacea showed better relation with angiosperms Ruppia cirrhosa, Potamogeton pectinatus and Zannichellia pallustris ssp. pedicellata and their companion species. Miscellanea showed better relation with the opportunistic species of aquatic macrophytes. Gammarus insensibilis presented co-occurrence with Chaetomorpha linum, which is a part of its diet, as referred also, in Sheader & Sheader (1987) and Bamber et al. (1992).
In the current study the ecological evaluation of the two coastal lagoons, the spatial and temporal fluctuations of environmental variables and their influence to the structure and function of biotic communities are further discussed.
|
272 |
Efeito do sedimento fino de origem terrestre sobre a fauna de macroinvertebrados bentônicos em riachos / Effect of Fine sediment on benthic macroinvertebrate in subtropical streamsVasconcelos, Márlon de Castro January 2007 (has links)
O aporte de sedimento fino é um dos principais agentes causadores de impactos a ecossistemas aquáticos. Este trabalho teve por finalidade avaliar por experimentalmente o efeito do sedimento fino sobre a fauna de macroinvertebrados bentônicos em um riacho subtropical. O local escolhido foi o rio Forqueta no distrito de Barra do Ouro pertencente ao município de Maquiné, RS. Foi adicionado por tratamento cerca 3138 cm3 de sedimento fino, separado em duas frações: areia fina (0 mm a 0,250mm) e areia grossa (0,25 mm a 1mm), em dois níveis, com e sem sedimento. Os dados foram analisados através por meio de uma Análise de Variância (ANOVA) de dois fatores para abundância total, riqueza e riqueza rarefeita, além de uma Análise de Variância Multivariada (MANOVA) para abundância relativa e composição de espécies e de uma Análise de Correspondência Canônica (pCCA), esta última, para avaliar o quanto eventos de perturbações influenciam a fauna aquática. A interação entre a velocidade do fluxo e os fatores envolvendo sedimentos também foram avaliados. O sedimento fino afetou negativamente a abundância total, a riqueza e a composição de espécies, mas não a riqueza rarefeita e a abundância relativa.O fluxo foi um importante fator para a distribuição da fauna avaliada, sendo a abundância, riqueza e a riqueza rarefeita maior em áreas com maior fluxo. Houve interação do fluxo com a areia fina, aumentando seu efeito sobre a abundância total e riqueza rarefeita em locais com maior velocidade de fluxo. A pCCA mostrou que eventos pontuais e de curta duração de acréscimo de sedimento fino não são danosos à fauna aquática. Os resultados obtidos mostram que o sedimento fino afeta de forma negativa a fauna de macroinvertebrados bentônicos em riachos, e este efeito negativo se dá por diversas formas, tais como redução do hábitat, perda da qualidade do alimento, estresse fisiológico e por outros. A relação da fauna com a velocidade pode ser atribuída às preferênciasecológicas dos grupos encontrados. Por alguns resultados divergirem de estudos prévios, o efeito do sedimento fino sobre a fauna aquática deve ser mais bem estudado. / One of the main forms by which aquatic ecosystems are impacted is the input of fine sediment. The objective of our study was to determinate by one experiment the effect of fine sediment on benthic macroinvertebrates in subtropical streams. The study area was the Forqueta River in Barra do Ouro district of Maquiné city, Rio Grande do Sul, Brazil. It’s was added 3138 cm3 of sediment, in two fractions: fine sand (0mm – 0.25mm) and coarse sand (0.25mm – 1mm) into the river with two levels (with or without sediment) . The data were analyzed by Analysis of Variance (ANOVA two-way) for abundance, richness and rarefied richness, the last one intended to compare species richness based on an equivalent number of individuals. Using Multivaried Analysis of Variance (MANOVA) we examined the effect of fine sediment on relative abundance and composition of species. Sediment was used as one factor in four levels. A Partial Canonical Correspondence Analysis (pCCA) was used to examine the effect of the disturbance event on communities. The interaction between the flow and the factors of the sediment was examined. There was a negative effect of fine sediment on abundance, richness and species composition, but the effect was null on relative abundance and rarefaction of species richness. The flow was important for distribution of individuals colleted. The abundance, species richness and rarefied richness were highest on places with fastest flows. The flow increased the effect of fine sand on abundance and rarefied richness. The pCCA showed that disturbance events of small frequency consisting of input of terrestrial sediment have no negative effects on benthic macroinvertebrate. The relationship between flow and benthic macroinvertebrates can be attributed to the ecological preferences of species. These results showed that fine sediment impact is harmful for benthic macroinvertebrates in streams, particularly in termsof abundance. This negative effect may be a consequence of loss of habitat, reduced food quality, physiological stress and others forms. Because some results differ from other studies, the effect of the fine sediment on the benthic macroinvertebrates needs to be better studied.
|
273 |
Preparing for offshore renewable energy development in the MediterraneanBray, Laura January 2017 (has links)
The development of offshore wind farms and marine renewable energy devices in the Mediterranean is central to both national, and international, energy strategies for countries bordering the Mediterranean Sea. The ecological impacts of marine renewable energy development in the Mediterranean region, although essential for policy makers, are as yet unknown. The Northern Adriatic is identified as a plausible site for offshore wind farm development. Using the wider region (Adriatic and Northern Ionian) as a case study, this thesis examines the likely impact to the marine environment if an offshore wind farm is established. Site suitability, based on wind speed, bathymetry, and larvae connectivity levels are investigated along with the plausibility of the turbines operating as artificial reefs in the area. As offshore wind farms may alter the larval connectivity and supply dynamics of benthic populations, a connectivity map was constructed to identify areas of high and low connectivity in the Adriatic Sea. The Puglia coast of Italy is a likely larval sink, and displays some of the highest connectivity within the region, suggesting potential inputs of genetic materials from surrounding populations. Considering offshore wind farms could operate as artificial reefs, an in-situ pilot project was established to simulate the presence of wind turbines. Macroinvertebrates colonized the new substrata within the first few months but were lower in abundance when compared to a natural hard substrata environment. Time, turbine location, and the material used for turbine construction all affected the macro-invertebrate communities. In addition, fish abundances, and diversity were lower around the simulated OWF foundations in comparison to a natural hard substrata environment, and no increases in fish abundance occurred around the simulated turbines when compared to reference sites of soft substrata. This observation was validated with the use of an ecosystem modelling software (Ecopath with Ecosim), which simulated the overall ecosystem level impacts that would occur if 50 offshore monopile wind turbines were introduced to the Northern Ionian and colonized by macroinvertebrate communities. When compared to the baseline scenario (no simulated introduction of an OWF), the introduction of new habitat had no discernible impacts to the structure or functioning of the marine ecosystem. Noticeable changes to the ecosystem were only apparent if fishing restrictions were enforced in parallel with the simulated offshore wind farm; the ecosystem appears to become more structured by top down predation. In addition seabirds are also impacted by the reduction of fishing discards as a food source. These results are the first attempt to quantify the suspected benefits of offshore wind farms operating as de-facto marine protected areas.
|
274 |
Paleoecologia de foraminíferos bentônicos do holoceno superior da baía de Sepetiba, Rio de Janeiro / Benthic foraminiferal paleoecology of upper holocene of Sepetiba Bay, Rio de JaneiroKarina Jennings da Silva 15 March 2006 (has links)
Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Esta dissertação desenvolve-se a partir de análises da microfauna de foraminíferos bentônicos dos sedimentos holocênicos da Baía de Sepetiba e do Manguezal de Guaratiba. A Baía de Sepetiba é um corpo de água semi- confinado, que é parte integrante do complexo Costeiro Guaratiba-Sepetiba no sudoeste do Rio de Janeiro. Para a realização do trabalho foram utilizados seis testemunhos da área do manguezal de Guaratiba e cinco da parte interna da Baía de Sepetiba. Foram classificados 108 espécies de foraminíferos bentônicos, 70 da Ordem ROTALIIDA, 28 da Ordem TEXTULARIIDA e 10 da Ordem MILIOLIDA. A distribuição dos foraminíferos no testemunho BS-02 mostra um aumento quali-quantitativo em direção ao topo, enquanto que o BS-03 mostra uma diminuição. De acordo com o Índice de Diversidade de Fisher, os dois testemunhos evidenciam um domínio de ambiente de salinidade normal para a baía. A presença de espécies características de águas frias no testemunho BS-02 indicam existir entrada de correntes frias na baía, bem como uma fauna de transição, decorrente do fluxo de correntes oceânicas trazer espécies de diferentes províncias geográficas para dentro desta. O testemunho BS-03, possivelmente marca dois eventos, um transgressivo de menor magnitude e um regressivo, que segue até os dias atuais. / This work was developed from analysis of benthic foraminifera associations encountered in Sepetiba Bay and Guaratiba Mangrove holocenic sediments. Sepetiba Bay is a semi-confined body of water, that is a part of Sepetiba- Guaratiba Coastal complex at Rio de Janeiro southwest. It has been used six cores from Guaratiba Mangrove and five cores from Sepetiba Bay. It has been identified 108 species of benthic foraminifera, 70 of ROTALIIDA Order, 28 of TEXTULARIIDA Order and 10 of MILIOLIDA Order. The distribution of specimens in core BS-02 increases the number of species as well as number of individuals upwards, while in core BS-03 decreases. Agreed Fisher Index, the two cores display existence of a normal salinity environment for Sepetiba Bay during the Holocene. The occurrence of characteristics species from cold water in core BS-02 point out an influence of cold currents in bay as well as a transition fauna function of ocean currents that bring species from different geographical provinces. Core BS-03 possibly high-lights two sea-level events, a transgressive event of minor order and a regressive event that happens until today.
|
275 |
Papel do peixe Malacanthus Plumieri (Actinopterygii) na estrutura dos bancos de rodolitos do Arquipélago de Fernando de Noronha - BrasilVeras, Priscila de Cerqueira January 2016 (has links)
Orientador: Prof. Dr. Guilherme Henrique Pereira Filho / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Evolução e Diversidade, 2016. / Engenheiros Ecossistemicos (EE) modulam a disponibilidade de recursos no ambiente. Este e o caso dos rodolitos (i.e. gnodulos de vida livreh compostos por mais de 50% de algas calcarias incrustantes que formam bancos em fundos inconsolidados) que promovem habitats para diversos organismos. Por outro lado, muitos desses organismos modulam condicoes para o crescimento de rodolitos. Esta interacao resulta na criacao de redes altamente dependentes de EEs. O peixe Malacanthus plumieri move rodolitos para a construcao de montes. Esta movimentacao altera o estado fisico de nodulos e, possivelmente, contribua para a diferenciacao das comunidades associadas. Portanto, avaliamos se as comunidades de macrofauna vagil (> 500¿Êm) presentes nos montes sao afetadas de forma positiva, negativa ou neutra em relacao a area controle (i.e. sem interferencia do M. plumieri). Alem disso, procuramos identificar as principais variaveis fisicas, que sao alteradas pelo peixe, que predizem a estrutura da macrofauna associada aos rodolitos. Para tanto, amostramos no Arquipelago de Fernando de Noronha 30 rodolitos na area controle e 30 nos montes. Cada nodulo foi individualmente inserido em sacolas de nylon com malha de 500¿Êm. Os epibiontes foram removidos e identificados. Mensuramos volume e diametros de cada rodolito e quantificamos o peso seco das macroalgas e do sedimento. Observamos que rodolitos da area controle apresentaram maior quantidade de macroalgas epifitas e sedimentos aprisionados quando comparados com rodolitos presentes nos montes (t=-0,04, p<0,001 e t=-0,54, p <0,001; respectivamente). A bioturbacao causada por M. plumieri altera as condicoes para o estabelecimento da macroalgas, reduzindo as taxas de sedimentos aprisionados. Como resultado, ha uma reducao na abundancia, riqueza e densidade de macroinvertebrados (t=-7,42, p<0,001; t=-7,92, p<0,001; t=-2,84, p<0,01; respectivamente). Portanto, M. plumieri afeta indiretamente a comunidade de macroinvertebrados vageis. Em contraste com outros estudos, o efeito da coexistencia destes EEs parece ser antagonico (i.e. positivo para a abundancia e riqueza de ictiofauna e negativo para macroalgas e macroinvertebrados). Assim, mudancas estruturais no sistema, embora promovidas pelo mesmo EE, influenciam comunidades de diferentes maneiras e sao dependentes da escala dos organismos em questao. / Ecosystem engineers (EE), such as rhodoliths, control the availability of resources in the environment, providing habitats for other organisms, as other algae and many animals. Some of these organisms are able to modulate the environmental conditions where rhodoliths grow, thus forming a highly dependent network. The sand tilefish Malacanthus plumieri, for example, moves rhodoliths to build mounds over their burrows. This behavior changes the physical medium in which the nodules are, and therefore, their associated communities¿ structure and composition. We assessed the effect of communities associated with mounds in comparison to non-mounded areas (i.e. rhodolith areas without the interference of the tilefish). Additionally, we seek to identify the main physical variables changed by the action of M. plumieri in predicting the structure of the macrofauna associated with rhodoliths. Rhodoliths from non-mounded areas showed higher amounts of epiphytic macroalgae and sediment trapped on rhodoliths than mounds (t=-0.04, p<0.001 and t=-0.54, p<0.001, respectively). Bioturbation caused by M. plumieri alters the conditions for macroalgae establishment, reducing the trapped sediment. As a result, there is also a reduction in the abundance, richness and density of macroinvertebrates (t=-7.42, p<0.001, t=-7.92, p<0.001, t=-2.84, p<0.01 respectively). The ecosystem role of M. plumieri indirectly affects the vagile macrofauna community. In contrast to other studies, the coexistence of these EEs (i.e. rhodoliths and tilefishes) seems to be antagonistic (i.e. positive for the abundance and richness of ichthyofauna and negative for macroalgae and macroinvertebrates). Thus, structural changes in the system, although promoted by the same EE, influence communities in different ways depending on the scale of the organisms in question.
|
276 |
MACROINVERTEBRADOS DA LAVOURA DE ARROZ IRRIGADO TRATADA COM OS AGROTÓXICOS CARBOFURAN E PENOXSULAM / THE RICEFIELD MACROINVERTEBRATES TREATED WITH CARBOFURAN AND PENOXSULAN PESTICIDESCamargo, Bruna Vielmo 24 September 2010 (has links)
The rice cultivation (Oryza sativa) has been target of speculations because of its
effects in the environment. The intensive pesticides uses in the ricefields have
contributed in a meaningful manner to many things related to this crop. The purpose
of this study was to compare the benthic macroinvertebrates community in an
irrigated rice farm treated with pesticides Carbofuran (insecticide) and Penoxsulam
(herbicide) comparing to a control farm. The experiment was accomplished in an
experimental lowland area, from the Crop Science Departament of the Universidade
Federal de Santa Maria, during the harvest 2008/2009. To a benthic fauna sampling,
it was used a Corer sampler. It was accomplished five benthic macroinvertebrates
sampling during the study, the delimitation was in blocks divided, by chance, with
three repetitions, and the sampling happened in 3rd, 14th, 28th and 56th day after the
water entrance in the system. Besides, it was accomplished the following
determination: pH, temperature, dissolved oxygen and the pesticides persistence in
the water. The analysed pesticides, the Penoxsulam herbicide showed the biggest
water persistence, that was detected until the sampling day (56th day), without much
oscillation in its concentration according to the studied period. Among the sampling
organisms, Chironomidae was the dominant group in the three treatments. This way,
the total individuals abundance in this study was confirmed by this family organisms,
which didn t suffer a variation among the treatments during the sampling days (twoway-
ANOVA). The analyses variance, which evaluated the total macroinvertebrates
abundance and the taxon richness, detected interactions between the day sampling
factors and the (two-way- ANOVA) treatments. The posterior test (Tukey HSD)
showed the abundance in the community in the 8th day the sampling was different in
parcels treated with Penoxsulam and Carbofuran. However, on the other samplings,
the organisms total abundance was similar in the two treatments (Carbofuran,
Penoxsulam and Control). The posterior taxons richness comparison showed that
just in the 56th sampling day the macroinvertebrates richness in the controlled parcels
was superior than in the parcels treated with Carbofuran insecticide. The Diversity
Shannon level varied during the sampling days, but there wasn t a meaningful
difference in the (two-way-ANOVA) treatment. The results indicated that the
macroinvertebrates colonization process in the control areas didn t have a
meaningful variation related to the areas treated with Penoxsulam Carbofuran,
showing that the tested pesticides didn t affected the benthic fauna colonization, in
the ricefields. On the other hand, it was verified a subtle diversity along to the
successional process evaluated in this study (from the 3rd to the 56th day). / O cultivo de arroz (Oryza sativa) tem sido alvo de especulações devido aos efeitos deste
sobre o ambiente. A utilização intensiva de agrotóxicos em lavouras de arroz tem
contribuído de maneira significativa para as inúmeras questões que estão surgindo sobre
esta cultura. Dessa forma, o objetivo desse estudo foi comparar a estrutura da comunidade
de macroinvertebrados bentônicos em lavoura de arroz irrigado tratada com os agrotóxicos
Carbofuran (inseticida) e Penoxsulam (herbicida) em relação a uma lavoura controle. O
experimento foi desenvolvido na área experimental de várzea, do Departamento de
Fitotecnia da Universidade Federal de Santa Maria, durante a safra agrícola 2008/2009.
Para a amostragem da fauna bentônica, utilizou-se um amostrador tipo Corer. Realizaramse
cinco amostragens de macroinvertebrados bentônicos ao longo do estudo, sendo que o
delineamento foi de blocos ao acaso com três repetições, e as amostragens ocorreram no
3°, 14°,28° e 56° dia após a entrada de água no sistema. Além destes, foram realizadas as
seguintes determinações: pH, temperatura, oxigênio dissolvido e persistência dos
agroquímicos na água. Dos agrotóxicos analisados, o que apresentou maior persistência na
água foi o herbicida Penoxsulam, o qual foi detectado até o último dia de amostragem (56°
dia), sem muita oscilação em suas concentrações ao longo de todo o período de estudo.
Dentre os organismos amostrados, Chironomidae foi o grupo dominante nos três
tratamentos. Dessa forma, a abundância total de indivíduos deste estudo foi regida pela
abundância exclusiva de organismos desta família, a qual não variou entre os tratamentos,
ao longo dos dias de amostragem (ANOVA two-way). As análises de variância, que
avaliaram a abundância total de macroinvertebrados e a riqueza de táxons, detectaram
interações entre os fatores dias de amostragem e tratamentos (ANOVA two-way). O teste a
posteriori (Tukey HSD) mostrou que a abundância da comunidade no 8° dia de amostragem
diferiu entre as parcelas tratadas com Penoxsulam e Carbofuran. No entanto, nos demais
dias de amostragem, a abundância total de organismos foi similar entre todos os
tratamentos ( Carbofuran, Penoxsulam e Controle) Já a comparação a posteriori da riqueza
de táxons revelou que apenas no 56° dia amostral a riqueza de macroinvertebrados nas
parcelas controle foi superior a das parcelas tratadas com o inseticida Carbofuran. O Índice
de Diversidade de Shannon variou ao longo dos dias de amostragem, porém não houve
diferença significativa entre os tratamentos (ANOVA two-way). De uma forma geral, os
resultados indicam que o processo de colonização pelos macroinvertebrados nas áreas
controle não variou significativamente em relação as áreas tratadas com Penoxsulam
Carbofuran, demonstrando assim que os agrotóxicos testados não afetaram a colonização
da fauna bentônica, nas áreas de cultivo de arroz irrigado. No entanto, verificou-se um
aumento sutil da diversidade ao longo do processo sucessional avaliado neste estudo (do 3°
ao 56° dia).
|
277 |
IMPACTO DE AGROTÓXICOS USADOS NA LAVOURA DE ARROZ IRRIGADO EM ORGANISMOS BENTÔNICOS / THE IMPACT OF PESTICIDES ON BENTHIC ORGANISMS IN FLOODED RICEFIELDSBaumart, Joele Schmitt 23 February 2010 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this project was to investigate the impact of different
pesticides used in the ricefield on the density and diversity of benthic organisms. In
the experiment, two collects of soil were made to identify and quantify benthic
organisms, one in the 28th and other in the 84th days after the entry of water in the
ricefield. We used a cylindrical collector of PVC (Curer) with 0.10 m in diameter
(0.01 m2) at a depth of 0.10 m. Samples were collected in the irrigated plots that
received the following treatments: TO - Imazethapyr + Imazapic (ONLY ®), TB -
Bispyribac-sodium (NOMINEE 400SC), TQ - Quinclorac (FACET PM), TF - Fipronil
(STANDACK) and TC - control. The number of replicates for each treatment was 12
samples per day. The collected material was stored in plastic bags and taken to the
laboratory, where it was washed in sieves of 0.25 mm and re-packed in plastic
bottles and then immediately stained (Rose-Bengal), and fixed with absolute
ethanol. After fixing, the organisms were separated and identified to the lowest
taxonomic level possible, using specialized bibliographies. Throughout the period of
ricefield, data on the following parameters of irrigation water were recorded:
dissolved oxygen, pH, temperature, alkalinity, hardness, turbidity, conductivity and
persistence of pesticides used. To verify differences in the physical-chemical,
between treatments, we used a TWO-WAY-ANOVA (treatment and time) and a
PCA. An ANOVA one criterion was used to verify differences in taxa between
treatments and a MANOVA was used to examine differences in fauna composition
between treatments and trophic guilds. There were no differences among abiotic
data and the treatment, but differences were found in the time of cultivation.
Concerning the persistence of pesticides, the herbicide quinclorac was the most
persistent, detected up to the 84th day. The lower persistence of the herbicide
ONLY® was detected until the 21st day. In the first sample a total of 1971 animals
was collected from all treatments, separated into four phyla: Arthropoda (Insecta,
Arachnida and Crustacea), Mollusca (Gastropoda), Anellida (Oligochaeta and
Hirudinea) and Nematoda. In the second group of samples, 2295 individuals were
identified among all treatments. The same phyla were present, but the diversity of
insects was higher than in the previous collection. The MANOVA showed
differences between the fauna composition of the treatments evaluated, and
between collections, as well as among the fauna composition of the same trophic
guild in the different treatments. Based on these results we conclude that the
pesticides did not affect the physical and chemical parameters of water, however,
these products can cause stress on the benthic community at the beginning of
culture for a period of approximately one month after the entry of water in the plots.
This effect is reduced over time so that the benthic community tends to restructure
after the period of greatest activity of pesticides in water. / O objetivo deste estudo foi investigar o impacto da utilização de diferentes
agroquímicos, empregados na lavoura de arroz irrigada por inundação, sobre a
densidade e riqueza de organismos bentônicos. No experimento, foram realizadas
duas amostragens de solo para identificar e quantificar organismos bentônicos,
uma no 28º e outra no 84º dia após a entrada de água na lavoura. Utilizou-se um
coletor cilíndrico de PVC (Corer) com 0,10 m de diâmetro (0,01 m2) na
profundidade de 0,10 m. As amostragens foram realizadas em parcelas que
receberam os seguintes tratamentos: TO -imazethapyr + imazapic (ONLY®); TB -
bispyribac-sodium (NOMINEE 400SC); TQ - quinclorac (FACET PM); TF - fipronil
(STANDACK) e TC - controle. O número de réplicas para cada tratamento foi de 12
amostras por dia amostral. O material coletado foi armazenado em sacos plásticos
e levado para o laboratório, onde foi lavado em peneiras de 0,25mm, reacondicionado
em frascos plásticos e logo em seguida corado (Rosa-de-Bengala) e
fixado com álcool etílico absoluto. Após a fixação os organismos foram triados e
identificados até o menor nível taxonômico possível, utilizando-se bibliografias
especializadas. Durante todo o período da cultura do arroz foram registrados os
dados dos seguintes parâmetros da água de irrigação: Oxigênio dissolvido, pH,
temperatura, alcalinidade, dureza, turbidez, condutividade e persistência dos
pesticidas utilizados. Para verificar diferenças quanto aos fatores físico-químicos,
entre os tratamentos, utilizou-se uma ANOVA de dois critérios (tratamento e tempo)
e uma PCA. Uma ANOVA de um critério foi utilizada para verificar diferenças dos
táxons entre os tratamentos e uma MANOVA foi empregada para analisar
diferenças na composição da fauna entre os tratamentos e guildas tróficas. Não se
observou diferenças nos dados abióticos em relação aos tratamentos, mas sim em
relação ao tempo de cultivo. Com relação à persistência dos pesticidas, o herbicida
Quinclorac foi o mais persistente, detectado até o 84º dia. A menor persistência foi
do herbicida Only, detectado até o 21º dia. Na primeira amostragem foram
coletados um total de 1971 organismos entre todos os tratamentos, pertencentes a
quatro filos: Arthropoda (Insecta, Arachnida e Crustacea), Mollusca (Gastropoda),
Anellida (Hirudinea e Oligochaeta) e Nematoda. Na segunda coleta foram
identificados 2295 organismos entre todos os tratamentos. Os mesmos filos
estiveram presentes, porém a riqueza de insetos foi maior que na coleta anterior. A
Manova mostrou haver diferenças entre as composições da fauna dos tratamentos
avaliados, e entre as coletas, bem como na composição da fauna, de uma mesma
guilda trófica, nos diferentes tratamentos. Com base nestes resultados é possível
concluir que os pesticidas utilizados não afetaram os parâmetros físico-químicos da
água, entretanto, esses produtos podem causar estresse na comunidade bentônica
no início da cultura, por um período de aproximadamente um mês após a entrada
de água nas parcelas. Este efeito é reduzido com o passar do tempo, de maneira
que a comunidade bentônica tende a se reestruturar após o período de maior ação
dos pesticidas na água.
|
278 |
Efeito do sedimento fino de origem terrestre sobre a fauna de macroinvertebrados bentônicos em riachos / Effect of Fine sediment on benthic macroinvertebrate in subtropical streamsVasconcelos, Márlon de Castro January 2007 (has links)
O aporte de sedimento fino é um dos principais agentes causadores de impactos a ecossistemas aquáticos. Este trabalho teve por finalidade avaliar por experimentalmente o efeito do sedimento fino sobre a fauna de macroinvertebrados bentônicos em um riacho subtropical. O local escolhido foi o rio Forqueta no distrito de Barra do Ouro pertencente ao município de Maquiné, RS. Foi adicionado por tratamento cerca 3138 cm3 de sedimento fino, separado em duas frações: areia fina (0 mm a 0,250mm) e areia grossa (0,25 mm a 1mm), em dois níveis, com e sem sedimento. Os dados foram analisados através por meio de uma Análise de Variância (ANOVA) de dois fatores para abundância total, riqueza e riqueza rarefeita, além de uma Análise de Variância Multivariada (MANOVA) para abundância relativa e composição de espécies e de uma Análise de Correspondência Canônica (pCCA), esta última, para avaliar o quanto eventos de perturbações influenciam a fauna aquática. A interação entre a velocidade do fluxo e os fatores envolvendo sedimentos também foram avaliados. O sedimento fino afetou negativamente a abundância total, a riqueza e a composição de espécies, mas não a riqueza rarefeita e a abundância relativa.O fluxo foi um importante fator para a distribuição da fauna avaliada, sendo a abundância, riqueza e a riqueza rarefeita maior em áreas com maior fluxo. Houve interação do fluxo com a areia fina, aumentando seu efeito sobre a abundância total e riqueza rarefeita em locais com maior velocidade de fluxo. A pCCA mostrou que eventos pontuais e de curta duração de acréscimo de sedimento fino não são danosos à fauna aquática. Os resultados obtidos mostram que o sedimento fino afeta de forma negativa a fauna de macroinvertebrados bentônicos em riachos, e este efeito negativo se dá por diversas formas, tais como redução do hábitat, perda da qualidade do alimento, estresse fisiológico e por outros. A relação da fauna com a velocidade pode ser atribuída às preferênciasecológicas dos grupos encontrados. Por alguns resultados divergirem de estudos prévios, o efeito do sedimento fino sobre a fauna aquática deve ser mais bem estudado. / One of the main forms by which aquatic ecosystems are impacted is the input of fine sediment. The objective of our study was to determinate by one experiment the effect of fine sediment on benthic macroinvertebrates in subtropical streams. The study area was the Forqueta River in Barra do Ouro district of Maquiné city, Rio Grande do Sul, Brazil. It’s was added 3138 cm3 of sediment, in two fractions: fine sand (0mm – 0.25mm) and coarse sand (0.25mm – 1mm) into the river with two levels (with or without sediment) . The data were analyzed by Analysis of Variance (ANOVA two-way) for abundance, richness and rarefied richness, the last one intended to compare species richness based on an equivalent number of individuals. Using Multivaried Analysis of Variance (MANOVA) we examined the effect of fine sediment on relative abundance and composition of species. Sediment was used as one factor in four levels. A Partial Canonical Correspondence Analysis (pCCA) was used to examine the effect of the disturbance event on communities. The interaction between the flow and the factors of the sediment was examined. There was a negative effect of fine sediment on abundance, richness and species composition, but the effect was null on relative abundance and rarefaction of species richness. The flow was important for distribution of individuals colleted. The abundance, species richness and rarefied richness were highest on places with fastest flows. The flow increased the effect of fine sand on abundance and rarefied richness. The pCCA showed that disturbance events of small frequency consisting of input of terrestrial sediment have no negative effects on benthic macroinvertebrate. The relationship between flow and benthic macroinvertebrates can be attributed to the ecological preferences of species. These results showed that fine sediment impact is harmful for benthic macroinvertebrates in streams, particularly in termsof abundance. This negative effect may be a consequence of loss of habitat, reduced food quality, physiological stress and others forms. Because some results differ from other studies, the effect of the fine sediment on the benthic macroinvertebrates needs to be better studied.
|
279 |
Unique Cellular, Physiological, and Metabolic Adaptations to the Euendolithic Lifestyle in a Boring Cyanobacterium.January 2016 (has links)
abstract: Euendolithic cyanobacteria have the remarkable ability to actively excavate and grow within certain minerals. Their activity leads to increased erosion of marine and terrestrial carbonates, negatively affecting coral reef and bivalve ecology. Despite their environmental relevance, the boring mechanism has remained elusive and paradoxical, in that cyanobacteria alkalinize their surroundings, typically leading to carbonate precipitation, not dissolution. Thus, euendoliths must rely on unique adaptations to bore. Recent work using the filamentous model euendolith Mastigocoleus testarum strain BC008 indicated that excavation relied on transcellular calcium transport mediated by P-type ATPases, but the phenomenon remained unclear. Here I present evidence that excavation in M. testarum involves an unprecedented set of adaptations. Long-range calcium transport is achieved through the coordinated pumping of multiple cells, orchestrated by the localization of calcium ATPases in a repeating annular pattern, positioned at a single cell pole, adjacent to each cell septum along the filament. Additionally, specialized chlorotic cells that I named calcicytes, differentiate and accumulate calcium at concentrations more than 500 fold those of canonical cells, likely allowing for fast calcium flow at non-toxic concentrations through undifferentiated cells. I also show, using 13C stable isotope tracers and NanoSIMS imaging, that endolithic M. testarum derives most of its carbon from the mineral carbonates it dissolves, the first autotroph ever shown to fix mineral carbon, confirming the existence of a direct link between oxidized solid carbon pools and reduced organic pools in the biosphere. Finally, using genomic and transcriptomic approaches, I analyze gene expression searching for additional adaptations related to the endolithic lifestyle. A large and diverse set of genes (24% of 6917 genes) were significantly differentially regulated while boring, including several master regulators and genes expectedly needed under this condition (such as transport, nutrient scavenging, oxidative stress, and calcium-binding protein genes). However, I also discovered the up-regulation of several puzzling gene sets involved in alternative carbon fixation pathways, anaerobic metabolism, and some related to photosynthesis and respiration. This transcriptomic data provides us with several new, readily testable hypotheses regarding adaptations to the endolithic lifestyle. In all, my data clearly show that boring organisms show extraordinarily interesting adaptations. / Dissertation/Thesis / Doctoral Dissertation Microbiology 2016
|
280 |
Estudo biogeoquímico do fósforo no complexo estuarino-lagunar de Cananéia-Iguape (SP): influência do Valo Grande e fluxo bêntico / Biogeochemical study of phosphorus in estuarine lagoon complex of Cananeia-Iguape (SP): Valo Grande influence and benthic fluxLivia Haubert Ferreira Coelho 09 September 2011 (has links)
Este estudo teve como objetivo conhecer a dinâmica do ciclo biogeoquímico do fósforo (P) (fases dissolvidas e particuladas) no Complexo estuarino-lagunar de Cananéia-Iguape considerando a influencia antrópica causada pela abertura do canal do Valo Grande e as possíveis diferenças no fluxo bêntico de PID. Foram observados valores de P dissolvido e particulado superiores no setor norte (Iguape) indicando a influência do aporte do Valo Grande ao estuário. As concentrações de P no sedimento foram maiores também no norte, sendo dominada pela fração inorgânica. Nas estações fixas de Cananéia (verão e inverno), a influência da maré foi evidente, enquanto em Iguape não foi observado sinal considerável. O fluxo do PID observado nas campânulas bênticas foi negativo indicando a remoção para o sedimento, consequente retenção do P neste compartimento. O Valo Grande influenciou o ciclo biogeoquímico do P na região, de forma mais acentuada ao norte do sistema e, a fração particulada em suspensão foi a forma que mostrou maior potencial para exportação de P para o oceano adjacente. O estudo do ciclo biogeoquímico do P em sistemas estuarinos constitui uma excelente ferramenta para o diagnóstico da qualidade ambiental, auxiliando também, os gestores ambientais em suas ações de preservação e manejo. / This study aims to know the dynamic of phosphorus biogeochemical cycle (P) (dissolved and particulate forms) in Cananéia-Iguape Estuarine-Lagoon Complex, considering the anthropogenic influence caused by the opening of Valo Grande channel and the possible differences in DIP benthic flux. Higher values of dissolved and particulate P were observed in the northern sector (Iguape), indicating the influence of the Valo Grande contribution to the estuary. P concentrations in sediment were also higher in the north, and the inorganic fraction prevailed. In Cananéia\'s fixed stations (summer and winter), the influence of the tide was evident, while in Iguape an extensive signal was not observed. The DIP flux observed in the benthic chambers was negative, indicating the removal to the sediment, and therefore the retention of P in this compartment. The Valo Grande influenced the P biogeochemical cycle in this region, the north of the system in a more sharply way. The suspended particulate P form showed the biggest potential to exportation of P to the adjacent ocean. The study of P biogeochemical cycle in estuarine systems is an excellent tool to diagnose environmental quality, also helping environmental managers in their actions of preservation and management.
|
Page generated in 0.0635 seconds