Allelopathy can be important in aquatic organisms, especially algae, plants, and bacteria. All major groups of aquatic primary producers produce allelochemicals that act against their competitors, especially by interfering with enzymatic action or photosynthesis. Emerging wetland plants use allelochemicals that oppose each other. Planktonic macrophytes such as Eichhornia are allelopathic because they must compete with other primary producers for nutrients dissolved in water. Rooted macrophytes often get their nutrients from the sediments, but they can be shaded by epiphytic algae growing on them and phytoplankton growing on them. These macrophytes often use allelopathy to compete with primary producers that affect their ability to gather light. Such interactions are responsible for the sharp shift between phytoplankton and macrophyte dominance in shallow lakes. Allelopathies also occur in benthic and pelagic microalgae and cyanobacteria. Allelopathy seems to be strongest in still waters where the chemicals released can affect nearby competitors. No profit. An exception could be local interactions between benthic algae. In many aquatic species, polyploid specimens are viable and specimens with heterogeneous chromosome sets are usually sterile. The fact that specimens raised in fish farms are sterile may be advantageous in production, either because greater growth occurs or because specimens are used in sanctuary reintroduction programs to prevent the introduction of invasive species. Transmission of an aquatic species is the movement of that species within its geographical range. Migration generally occurs to support stressed populations, improve genetic traits, or restore locally failing species (GESAMP, 1991). Department of Energy's Office of Fuel Development to develop renewable transportation fuels from algae. Many aquatic organisms benefit from production on land and vice versa. In addition to leaves, large amounts of fruits, flowers, seeds, insects, and droppings fall from the canopy into the stream, providing an important source of energy and nutrition for the biota. These are mouthbrooders commonly found in cichlids. Involvement of males in parental care is common among fish, with males building nests, guarding eggs and brood, and may even participate in mouthbrooders. Introduction is the movement of a species beyond its current geographical range. Introductions are designed to introduce new taxa to the flora and fauna of the environment. Diverse communities of emerging, submerged, and floating aquatic plants, especially those with brightly colored flowers, add to the overall beauty of lakes and ponds. One is that abundant native plant populations reduce the effectiveness of exotic invasive vegetation to colonize lakes and ponds. Also, when the aquatic plant community is balanced, it is more likely that other aquatic organisms such as fish and plankton will also be balanced. Another thing to note is that even healthy communities of native aquatic plants can become thorny requiring active management to maximize the use of water bodies for recreation. Dense emerging plant communities crowd out the more desirable slow-growing plants, and when floating plants completely cover a body of water, it can create frustrating fishing conditions. Ultimately, it's all about finding the right balance for each individual aquatic ecosystem. Among the grasses and reeds, microscopic creatures and invertebrates feed on a wide variety of fish, shrimp, crabs, mammals, reptiles, amphibians and birds.