These macroalgal fronds tend to be utilized by benthos in the intertidal zone close to the shore. Macroalgae and macroalgal detritus have also been shown to be an important food source for benthic organisms, because macroalgae shed old fronds. In this habitat, seaweed must withstand rapidly changing temperature and salinity and occasional drying. Others have adapted to live in tidal rock pools. The deepest living seaweed are some species of red algae. In some areas, littoral seaweed colonies can extend miles out to sea. At the surface, they are only wetted by the tops of sea spray, while some species may attach to a substrate several meters deep. ![]() Seaweed occupies various ecological niches. In addition, there are few genera (e.g., Sargassum and Gracilaria) which do not live attached to the sea floor, but float freely. Another common requirement is an attachment point, and therefore seaweed most commonly inhabits the littoral zone (nearshore waters) and within that zone, on rocky shores more than on sand or shingle. These are seawater (or at least brackish water) and light sufficient to support photosynthesis. ![]() Two environmental requirements dominate seaweed ecology. The stipe and blade are collectively known as the frond.Įcology Seaweed covers this rocky seabed on the east coast of Australia Haptera: finger-like extension of the holdfast that anchors to a benthic substrate.Holdfast: basal structure providing attachment to a substrate.Stipe: stem-like structure, may be absent.Kelp, float: a flotation-assisting organ between the lamina and stipe.pneumatocyst, air bladder: a flotation-assisting organ on the blade.Lamina or blade: flattened structure that is somewhat leaf-like.Seaweed's appearance resembles non- woody terrestrial plants. The following table lists a very few example genera of seaweed. The number of seaweed species is still discussed among scientists, but most likely there are several thousand species of seaweed. In addition, bluegreen algae ( Cyanobacteria) are occasionally considered in seaweed literature. They lack one common multicellular ancestor, forming a polyphyletic group. Generally, it is one of several groups of multicellular algae: red, green and brown. The term refers to both flowering plants submerged in the ocean, like eelgrass, as well as larger marine algae. "Seaweed" lacks a formal definition, but seaweed generally lives in the ocean and is visible to the naked eye. The IPCC Special Report on the Ocean and Cryosphere in a Changing Climate recommends "further research attention" as a mitigation tactic. Because of their importance in marine ecologies and for absorbing carbon dioxide, recent attention has been on cultivating seaweeds as a potential climate change mitigation strategy for biosequestration of carbon dioxide, alongside other benefits like nutrient pollution reduction, increased habitat for coastal aquatic species, and reducing local ocean acidification. In recent years, seaweed farming has become a global agricultural practice, providing food, source material for various chemical uses (such as carrageenan), cattle feeds and fertilizers. Humans have a long history of cultivating seaweeds for their uses. Other forces also threaten some seaweed ecosystems a wasting disease in predators of purple urchins has led to a urchin population surge which destroyed large kelp forest regions off the coast of California. ![]() For example, mechanical dredging of kelp destroys the resource and dependent fisheries. Natural seaweed ecosystems are sometimes under threat from human activity. Seaweed species such as kelps provide essential nursery habitat for fisheries and other marine species and thus protect food sources other species, such as planktonic algae, play a vital role in capturing carbon, producing at least 50% of Earth's oxygen. The term includes some types of Rhodophyta (red), Phaeophyta (brown) and Chlorophyta (green) macroalgae. Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. Seaweeds can be found in the following groupsĪscophyllum nodosum exposed to the sun in Nova Scotia, Canada Dead man's fingers ( Codium fragile) off the Massachusetts coast in the United States The top of a kelp forest in Otago, New Zealand Informal group of macroscopic marine algae
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