Complex sentence: This free-floating nature can allow for increased hemocyanin density over hemoglobin and increased oxygen carrying capacity, likewise free-floating hemocyanin can increase viscosity and increase the energy expenditure needed to pump blood.
Split into simpler sentences: This free-floating nature can allow for increased hemocyanin density over hemoglobin and increased oxygen carrying capacity. On the other hand, free-floating hemocyanin can increase viscosity and increase the energy expenditure needed to pump blood.