Green sea turtles inhabit various EP habitats and feed on marine macroalgae and invertebrates from diverse environments, which is evidenced in variation in bulk tissue SIA and d15N at 16 foraging sites.
Stable isotope values vary among foraging sites, with mean d15N values drastically differing depending on region and site. This suggests that green turtles occupy a wide niche space within EP.
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Seagrasses
Seagrasses play an essential part in the marine food chain. They serve as habitat for various fish, marine mammals and birds as well as protection from predators; in addition they provide important sources of nutrients while sequestering carbon from the atmosphere.
Researchers from ACCSTR have discovered that green turtles use seagrass meadows as foraging habitat. Their results demonstrated that seagrasses form an essential component of male and non-breeding female turtles’ diets – with Thalassodendron ciliatum being present in 90% of sampled turtle gut contents! Furthermore, other sources like substrate consumption, epiphytic cnidarians, and sponges were also considered key parts of these creatures’ daily meals.
Seagrass meadows provide essential sustenance for dugongs (Dugongdugons), green turtles and many other marine organisms including marine mammals such as manatees, conches and urchins; additionally they serve as an important habitat for wading and diving birds, who rely on seagrass meadows as their primary foraging grounds and feed off of detritus produced from the decomposition of seagrass leaves and roots by bacteria.
Jellyfish
Green sea turtles play an integral role in ocean ecosystems. They replenish beach and sea grass nutrients while their diet of jellyfish, crabs and fish helps balance marine vegetation. Furthermore, their reproduction ensures more genetically diverse generations of turtles will emerge – something male turtles returning home beaches and mating with females there can do.
Jellyfish are aquatic invertebrates with free-swimming tentacles characterized by radial symmetry and thousands of tiny stinging cells called nematocysts, which contain thousands of tiny stinging threads capable of paralyzing prey and injecting their victims with toxic venom.
Jellyfishes have an outer body composed of 95% water. These animals are well camouflaged; their only visible feature is their mouth with four to eight oral arms that they use to trap food and drag into its mouth for consumption. Jellyfish don’t possess brains but instead utilize an elaborate nervous system capable of sensing light stimuli and other environmental triggers.
Plankton
The world’s ocean waters are home to a vast variety of organisms known collectively as plankton. Phytoplankton, bacteria and fungi as well as animal-like creatures known as zooplankton all fall under this classification while larger species such as jellyfish and fish eggs or larvae can also be considered planktonic organisms. Plankton refers to any marine organism unable to swim against currents – most typically microscopic forms.
Phytoplankton use sunlight to convert carbon dioxide, found both in air and water, into sugars they can use to grow. They must live in shallow waters where there is sufficient light in order to survive; deep waters simply don’t provide enough light for their survival.
Zooplankton feed off phytoplankton, and are then consumed by larger marine creatures such as krill and baleen whales. Their in turn are preyed upon by larger marine organisms, including sea turtles that rely on both plant and animal sources for sustenance.
Crabs
Crabs play an essential role in the ocean food chain by providing various nutrients to marine organisms and serving as keystone species. Crabs also serve as essential food sources for turtles.
Sea turtles are omnivorous animals, feeding on both plants and animals – including crabs – making up part of their diet. Hatchling green sea turtles eat fish eggs and mollusks while adults tend to feast upon algae, sea grass, small/medium-sized fish as well as crabs in their daily meals.
The green sea turtle (Chelonia mydas) is a large marine turtle found worldwide and gets its name from its characteristically green fat undercarapace.
Researchers speculate that warmer egg temperatures are contributing to the decline of this species by decreasing male turtle numbers; males are essential in breeding with females and producing new generations of turtles.
