MARSILDA QYLI (MEMAJ)*, VALBONA ALIKO
Department of Biology, Faculty of Natural Sciences, Tirana University, Albania
*Corresponding author e-mail: qylimarsilda@yahoo.com
Abstract
Hypoxia is one of the key threats to most of the marine environment. Although motile organisms have the potential to avoid the low oxygen conditions, they can suffer indirect and sub lethal impacts as a result. Little is known of how acute hypoxia affects physiology in crustaceans. The present study assesses the effect of hypoxia on the heart rate, hemolymph glucose levels and lysosomal membrane stability on Mediterranean crab, Carcinus aestuarii. The adult crabs C.aestuarii, were kept in hypoxic waters for 24 hours. Hypoxic conditions (50-60 mm Hg O2) were induced by allowing the crabs to consume their oxygen supply. The hemolymph glucose levels, the heart rate and neutral red retention time (NRRT) as a biomarker of lysosomal membrane stability have been assayed in both treatment (intact and eyestalk-ablated animals) and control groups. The hemolymph glucose level in intact animals were significantly increased (from 38.2 ± 3.2 to 141.2 ± 15.8 mg/dL, F=9.984, df =1, 11, p=0.010 so p<0.05), while in eyestalk-ablated animals has been slightly decreased (from 27±2.4 to 24±1.8 mg/dL, F=0.993, df=1, 10, p=0.343 so p>0.05). Heart rate were significantly increased by 30 % in treatment group after exposure to hypoxic water for 2 hours. NRRT has been significantly reduced in treatment group (from 120±25.2 to 42.3±11.4 min, p<0.05) after exposure to hypoxia. Our findings highlight the importance of understanding how environmental disturbances modify the physiological stress responses of crustaceans to survival hypoxia. Quantifying the relationship between physiological responses and environmental stressors, is crucial for developing mechanistic models that can predict how changes in disturbances over time in coastal ecosystems will impact ecological processes, particularly in the context of global climate change.
Key words: hypoxia, crustacean hyperglycemic hormone(CHH), hemolymph glucose level, heart rate, lysosomal membrane stability
