Os montes de MALACANTHUS PLUMIERI agem como modificadores da diversidade no fundo oceânico?
Data
2020-12-17
Autores
Souza, Erica Panachuk 
Orientadores
Yokoyama, Leonardo Querobim
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Um dos principais processos ecológicos que regulam a estrutura de comunidades e o funcionamento de ecossistemas é a heterogeneidade ambiental. Este processo é mediado por fatores físicos, químicos e biológicos que se inter-relacionam para aumentar as condições de ocupação de um determinado ambiente. No caso dos fatores biológicos, os ecossistemas marinhos e costeiros possuem diversos agentes biológicos que promovem a heterogeneidade ambiental, levando ao aumento da variedade de habitats e, consequentemente, da disponibilidade de recursos. Esses organismos atuam como engenheiros do ecossistema e, em alguns casos, podem alterar a paisagem do fundo oceânico. Um exemplo desses agentes é o peixe Malacanthus plumieri (Bloch, 1786) que constrói montes utilizando diferentes tipos de materiais disponíveis no assoalho oceânico, como fragmentos de rocha e corais, rodolitos, conchas e carapaças de cracas. Estas estruturas possuem materiais de diferentes tamanhos, inclusive, formando um substrato inconsolidado na base dos montes. Esses montes alteram as características físico-químicas do sedimento (oxigenação e microhabitats, por exemplo), e, portanto, seria esperado que a diversidade da macrofauna bentônica fosse maior no sedimento inconsolidado no interior dos montes do que em seu entorno. Partindo desse pressuposto, o objetivo deste trabalho foi analisar se a presença dos montes construídos por M. plumieri modificam a composição e a estrutura da macrofauna bentônica do substrato inconsolidado. Nossos resultados nos permitem afirmar que houve interferência positiva dos montes na riqueza e diversidade da macrofauna bentônica presente no sedimento inconsolidado localizado no interior dessas estruturas, sendo Polychaeta o táxon mais numeroso nesses espaços, seguido por Malacostraca e Gastropoda. No sedimento externo aos montes, os três principais táxons registrados foram Polychaeta, Malacostraca e Nematoda. Táxons como Polyplacophora, Turbellaria, Ophiuroidea, Echinoidea e Holothuroidea foram registrados exclusivamente no interior dos montes, enquanto Nematoda foi encontrado apenas nas adjacências dessas estruturas. Com isso, concluímos que a presença dos ninhos alterou o substrato arenoso na região analisada do Arquipélago de Alcatrazes.
One of the main ecological processes that regulate the structure of communities and the functioning of ecosystems is environmental heterogeneity. This process is mediated by physical, chemical, and biological factors that interrelate to increase the conditions of occupation of a given environment. In the case of biological factors, marine and coastal ecosystems have several biological agents that promote environmental heterogeneity, leading to an increase in the variety of habitats and, consequently, in the availability of resources. These organisms act as ecosystem engineers and, in some cases, can alter the seafloor landscape. An example of these agents is the fish Malacanthus plumieri (Bloch, 1786) which builds mounds using different types of materials available on the ocean floor, such as rock fragments and corals, rhodolites, shells and barnacle shells. These structures have materials of different sizes, even forming an unconsolidated substrate at the base of the mounds. These mounds alter the physicochemical characteristics of the sediment (oxygenation and microhabitats, for example), and, therefore, it would be expected that the diversity of benthic macrofauna would be greater in the unconsolidated sediment inside the mounds than in its surroundings. Based on this assumption, the objective of this work was to analyze whether the presence of mounts built by M. plumieri modify the composition and structure of the benthic macrofauna of the unconsolidated substrate. Our results allow us to affirm that there was a positive interference of the hills in the richness and diversity of the benthic macrofauna present in the unconsolidated sediment located inside these structures, with Polychaeta being the most numerous taxa in these spaces, followed by Malacostraca and Gastropoda. In the sediment outside the mounds, the three main taxa recorded were Polychaeta, Malacostraca and Nematoda. Taxons such as Polyplacophora, Turbellaria, Ophiuroidea, Echinoidea and Holothuroidea were recorded exclusively inside the hills, while Nematoda was found only in the vicinity of these structures. Thus, we conclude that the presence of the nests altered the sandy substrate in the analyzed region of the Alcatrazes Archipelago.
One of the main ecological processes that regulate the structure of communities and the functioning of ecosystems is environmental heterogeneity. This process is mediated by physical, chemical, and biological factors that interrelate to increase the conditions of occupation of a given environment. In the case of biological factors, marine and coastal ecosystems have several biological agents that promote environmental heterogeneity, leading to an increase in the variety of habitats and, consequently, in the availability of resources. These organisms act as ecosystem engineers and, in some cases, can alter the seafloor landscape. An example of these agents is the fish Malacanthus plumieri (Bloch, 1786) which builds mounds using different types of materials available on the ocean floor, such as rock fragments and corals, rhodolites, shells and barnacle shells. These structures have materials of different sizes, even forming an unconsolidated substrate at the base of the mounds. These mounds alter the physicochemical characteristics of the sediment (oxygenation and microhabitats, for example), and, therefore, it would be expected that the diversity of benthic macrofauna would be greater in the unconsolidated sediment inside the mounds than in its surroundings. Based on this assumption, the objective of this work was to analyze whether the presence of mounts built by M. plumieri modify the composition and structure of the benthic macrofauna of the unconsolidated substrate. Our results allow us to affirm that there was a positive interference of the hills in the richness and diversity of the benthic macrofauna present in the unconsolidated sediment located inside these structures, with Polychaeta being the most numerous taxa in these spaces, followed by Malacostraca and Gastropoda. In the sediment outside the mounds, the three main taxa recorded were Polychaeta, Malacostraca and Nematoda. Taxons such as Polyplacophora, Turbellaria, Ophiuroidea, Echinoidea and Holothuroidea were recorded exclusively inside the hills, while Nematoda was found only in the vicinity of these structures. Thus, we conclude that the presence of the nests altered the sandy substrate in the analyzed region of the Alcatrazes Archipelago.
Descrição
Citação
SOUZA, Erica Panachuk. Os montes de MALACANTHUS PLUMIERI agem como modificadores da diversidade no fundo oceânico? 2021. 32 f. Dissertação (Mestrado em Biodiversidade e Ecologia Marinha e Costeira) - Instituto do Mar, Universidade Federal de São Paulo, Santos, 2021.