Nocturnal variation of the zooplankton community in coral reef substrates at Isla del Coco National Park (Eastern Tropical Pacific)

Abstract

Introduction: Zooplankton is a major link in coral reef food webs and a source of nutrients for corals. Demersal zooplankton in coral reefs makes diel migrations at night to avoid predation by fish and corals, increasing abundance and biomass at night. Objectives: To study the composition and variation of the demersal and pelagic zooplankton community at night and to increase the taxonomic knowledge of the benthic copepod fauna over different substrates of a coral reef. Methods: Traps made of plastic, with a 100 μm mesh size collector cup attached, were placed for 12 hours between 5-10 m depth over four substrates: (1) sand, (2) small and (3) big colonies of Porites lobata, and (4) dead and alive corals. Sampling started at dusk (1800 h), and the collector cups were collected and replaced at 2100 and 0000, and the last samples removed at down (0600 h). Results: The highest abundance of zooplankton was capture over P. lobata colonies between 0000 to 0600 h. Copepods (adults, copepodites, and nauplii) dominated the community structure and were more abundant during all the time intervals and substrates. Pelagic copepods were more abundant than the benthic, however, not more diverse. Among the benthic copepods, 20 new records of harpacticoids and calanoids were registered for Isla del Coco and Costa Rican waters. Appendicularians and decapod larvae were also abundant. Changes in coral reef community structure were related with time and not with the kind of substrate, although some taxa were found only in a specific time interval or substrate. Conclusions: Community structure and abundance of demersal and pelagic coral reef zooplankton in Chatham Bay were dominated by copepods, larvaceans and decapod larvae, similar to other coral reefs around the world. The highest abundance peak of organisms in the water column between 0000 to 0600 h could be related to diel migration.

Emigration patterns of motile cryptofauna and their implications for trophic functioning in coral reefs

“…Calanoid copepods are an abundant group of emergent zooplankton (Alldredge & King, 1977), indeed were 6‐ to 15‐fold more abundant in the emergence traps compared with the remaining treatments, and contributed most to the total biomass of emergent fauna. The mean density of Appendicularia (0.02 ± 0.01 ind cm −3 ) in emergence traps was greater than in previous reports on the Great Barrier Reef (Alldredge & King, 1977) and elsewhere (Esquivel‐Garrote & Morales‐Ramírez, 2020). Appendicularia are predominantly pelagic (Gorsky & Fenaux, 1998) but have been found in demersal plankton samples on the Great Barrier Reef (e.g., Grutter et al, 2022).…”

“…Emergent zooplankton is a distinct group of marine invertebrates that migrate in response to external factors including moon phase, tides, water flow, and temperature (Alldredge & King, 1980 , 1985 ; Cortes et al, 2017 ; Esquivel‐Garrote & Morales‐Ramírez, 2020 ; Kramer et al, 2013a ; Porter & Porter, 1977 ). While our emergence traps captured the lowest density (0.13 ± 0.03 ind cm −3 ) and biomass (0.15 ± 0.03 mg cm −3 ) of cryptofauna from rubble (mean ± SD; n = 12), these values are within the ranges of those reported previously for emergent zooplankton from other benthic habitat types on the Great Barrier Reef (Alldredge & King, 1977 ; Sorokin & Sorokin, 2009 , 2010 ).…”

“…The zooplankton commonly comprises the early life‐history stages of many benthic taxa that disperse through the water column (Esquivel‐Garrote & Morales‐Ramírez, 2020 ; Palmer, 1988 ; Warwick et al, 1986 ). We found crustacean zoea, gastropod, and bivalve veligers, and fish larvae in emergence traps, which highlights the importance of rubble in supporting cryptofauna ontogenesis (Wolfe, Kenyon, & Mumby, 2021 ).…”

Nighttime migrations and behavioral patterns of Pempheris schwenkii

“…These zooplankton assemblages consist of diverse invertebrates, especially small, motile crustaceans, which are more abundant in exposed positions during night than during the day ( Longley, 1927 ; Hobson, 1965 , 1968 ; Starck & Davis, 1966 ). The composition of the available plankton differs markedly between day and night, with generally larger meroplanktonic forms (especially crustaceans and annelids) rising from the bottom into the water column after dark ( Alldredge & King, 1977 ; Porter & Porter, 1977 ; Esquivel-Garrote & Morales-Ramírez, 2020 ). Only a few swimming fish groups, such as Clupeidae and Atherinidae, may compete for this rich food resource with Pempheridae ( Hobson, 1974 ).…”

Diversity of marine plankton in coral reef ecosystems at Gosong Island, Southwest Aceh

“…Its important assignment is as part of the dynamic trophic [11]. According to [12] *Corresponding author: ananingtyas.s@gmail.com zooplankton has a close relationship with coral reef food webs and is a source of food for corals. Even [13] stated that most of the zooplankton live on coral reefs.…”