Diel vertical migration of copepods and its environmental drivers in subtropical Bahamian blue holes

• Published in: Aquatic ecology Vol. 55; no. 4; pp. 1157 - 1169
• Main Authors: Sha, Yongcui, Zhang, Huan, Lee, Marcus, Björnerås, Caroline, Škerlep, Martin, Gollnisch, Raphael, Herzog, Simon David, Ekelund Ugge, Gustaf, Vinterstare, Jerker, Hu, Nan, Pärssinen, Varpu, Hulthén, Kaj, Nilsson, P. Anders, Rengefors, Karin, Brönmark, Christer, Langerhans, R. Brian, Hansson, Lars-Anders
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.12.2021; Springer; Springer Nature B.V
• Subjects: Aquatic crustaceans; Bahamas; Biologi; Biological Sciences; Biology; Biomedical and Life Sciences; Blue hole; Calanoid copepod; Chlorophyll; Chlorophyll a; Colour; Copepoda; Cyclopoid copepod; Depth; Distribution; Ecological Modelling Group; Ecology; Ecosystems; Ekologi; Ekologisk modellering; Food availability; Food chains; Food chains (Ecology); Food resources; Food supply; Food webs; Freshwater & Marine Ecology; Interspecific relationships; Life Sciences; Natural Sciences; Naturvetenskap; Night; Pigmentation; Plankton; Predation; Predators; Seasonal variation; Seasonal variations; Seasonality; Segregation; Surface water; Ultraviolet radiation; Vertical distribution; Vertical migration; Vertical migrations; Zooplankton; Calanoid copepod; Ultraviolet radiation; Food availability; Vertical distribution; Predation; Cyclopoid copepod; Blue hole; Bahamas
• ISSN: 1386-2588; 1573-5125; 1573-5125
• DOI: 10.1007/s10452-020-09807-4

Diel vertical migration (DVM) is the most common behavioral phenomenon in zooplankton, and numerous studies have evaluated DVM under strong seasonality at higher latitudes. Yet, our understanding of the environmental drivers of DVM at low latitudes, where seasonal variation is less pronounced, remains limited. Therefore, we here examined patterns of vertical distribution in copepods in six subtropical Bahamian blue holes with different food web structure and tested the role of several key environmental variables potentially affecting this behavior. Day and night samplings showed that copepods generally performed DVM, characterized by downward migration to deeper depths during the day and upward migration to surface waters at night. Across all blue holes, the daytime vertical depth distribution of calanoid copepods correlated positively with both predation risk and depth of food resources (Chlorophyll a ), but was less affected by ultraviolet radiation (UVR). A potential explanation is that since UVR is a continuous threat across seasons, zooplankton have established photoprotective pigmentation making them less vulnerable to this threat. The copepods also showed a size-structured depth segregation, where larger individuals were found at deeper depths during the day, which further strengthens the suggestion that predation is a major driver of DVM in these systems. Hence, in contrast to studies performed at higher latitudes, we show that despite the constant exposure to UVR, predator avoidance and food availability are the most pronounced drivers of copepod DVM at those low latitudes, suggesting that the main driver of DVM may vary among systems, but also systematically by latitude.