Final answer:
Deep-sea bacteria that utilize chemosynthesis rather than photosynthesis are least affected by the absence of sunlight, whereas photosynthetic organisms like algae and water lilies would be greatly impacted.
Step-by-step explanation:
The organism that is least affected by the absence of sunlight would be the ones that do not rely on photosynthesis for their energy needs. Underwater ecosystems often have areas where sunlight does not penetrate, and certain organisms have adapted to these conditions. For example, in hydrothermal vents, bacteria have evolved to extract energy from inorganic chemicals through a process known as chemosynthesis, rather than relying on sunlight for photosynthesis. On the other hand, photosynthetic organisms like algae and plants would be greatly affected, as their primary energy source is sunlight.
Photosynthetic organisms that rely on sunlight to produce energy through photosynthesis include plants and certain types of algae. These organisms use a mixture of pigments to absorb a range of light wavelengths for photosynthesis. However, those that grow in deep waters, under dense canopies in rainforests, or within areas that are shaded or dark must have adapted strategies to cope with low light conditions.
Thus, photosynthetic organisms such as the water lily, which depend on floating leaves to capture sunlight at the water's surface, would struggle in the absence of sunlight. Conversely, organisms adapted to environments with no light, such as certain deep-sea bacteria, would be least affected by its absence.