Zooplankton responses to sandbar opening in a tropical eutrophic coastal lagoon

• Published in: Estuarine, coastal and shelf science Vol. 71; no. 3; pp. 657 - 668
• Main Authors: Santangelo, Jayme M., de M. Rocha, Adriana, Bozelli, Reinaldo L., Carneiro, Luciana S., de A. Esteves, Francisco
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.02.2007; Elsevier
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Brachionus calyciflorus; Brachionus havanaensis; Brachionus plicatilis; Brackish water ecosystems; Brazil; coastal lagoons; community resilience; Copepoda; ecosystem disturbance; Fundamental and applied biological sciences. Psychology; Gastropoda; General aspects; Marine; Rotifera; sandbar opening; Synecology; zooplankton; South America; Brazil; America; ASW, Brazil, Rio de Janeiro; ASW, Brazil, Rio de Janeiro, Macae, Imboassica Lagoon; Brazil; community resilience; ecosystem disturbance; zooplankton; sandbar opening; coastal lagoons; Brackish water environment; Perturbation; Coastal lagoon; Eutrophication; Resilience; Opening; Ecosystem; Zooplankton; Community
• ISSN: 0272-7714; 1096-0015
• DOI: 10.1016/j.ecss.2006.09.021

The effects of a disturbance by sandbar opening on the zooplankton community were evaluated through a long-term study in an eutrophic and oligohaline system, Imboassica Lagoon, Rio de Janeiro, Brazil. Zooplankton samples and limnological data were collected monthly from March 2000 to February 2003. Before the sandbar was opened in February 2001, the lagoon showed eutrophic conditions, with high mean nutrient concentrations and low salinity (total nitrogen – TN = 190.28 μM, chlorophyll a content – Chl. a = 104.60 μg/L and salinity = 0.87′). During this period, the zooplankton species present, such as the rotifers Brachionus calyciflorus and Brachionus havanaensis, were typical of freshwater to oligohaline and eutrophic environments. After the sandbar opening, the lagoon changed to a lower trophic status and increased salinity (TN = 55.11 μM, Chl. a = 27.56 μg/L and salinity = 19.64′). As a result, the zooplankton community came to consist largely of the rotifer Brachionus plicatilis, marine copepods and meroplanktonic larvae, mainly Gastropoda. Salinity was the main force structuring the zooplankton community after the sandbar opening. Two years after this episode, the prior zooplankton community had not reestablished itself, indicating a low resilience to this disturbance. The conditions developed prior to a sandbar opening can be crucial to the community responses in the face of this disturbance and for the capacity of the original zooplankton community to re-establish itself.