Biomassa e densidade do zooplâncton no Parque Estadual Marinho da Pedra da Risca do Meio (Ceará, Brasil)

Abstract

Plankton is an important component in the maintenance of marine life, especially with regard to the food chain. Zooplankton (animal fraction, with heterotrophic organisms) has significant relevance as it is the main link between phytoplankton and other organisms at higher trophic levels, thus enabling the exchange of energy. In addition, they can play the role of environmental bioindicators. The Pedra da Risca do Meio Marine State Park (PEMPRIM) is located 10 nautical miles from the capital of Ceará, Fortaleza, and is a fully submerged conservation unit. However, data on the biological diversity of the region are scarce. The main objective of this work is to analyze and compare zooplankton density and biomass in the Park. Plankton collection was carried out at 10 stations, five of which are within the Marine Park and five in the surroundings of the Conservation Unit; being three before the perimeter of the Park and two after the Park. Nets of 65, 200 and 300 μm were used and a total of 30 zooplankton samples were collected, which were then stored in the plankton collection Profa. Mariana Ferreira de Menezes from the Plankton Laboratory at LABOMAR/UFC. The particulate organic biomass was higher in the 65 μm network, with a mean of 0.91 mg/m3 and a standard deviation of 0.36; for the 200 and 300 μm nets, the average was 0.34 mg/m3 and 0.21 mg/m3, with standard deviations of 0.12 and 0.08, respectively. Regarding density, holoplankton (organisms that spend their entire life cycle in plankton) had higher values in the three networks used, with a minimum of 1.08 ind/m3 in the 300 μm network and a maximum of 457.42 ind /m3 in the 65 μm network; while meroplankton (planktonic larvae that will spend the rest of their life cycle as benthos or nekton) recorded a minimum value of 0.23 ind/m3 in the 300 μm net and a minimum of 376.42 ind/m3 in the 65 μm net. The results obtained are consistent with the reality of the state where the Park is located and also of the Brazilian northeast region.