Vertical distribution of Macrocystis is apparently affected more by local conditions than by preferences or a specific range of depths. It lives in cold, clear waters where it forms large, dense kelp forests that provide habitat for thousands of other marine species. Giant Kelp (Macrocystis pyrifera) Status of the Population: The size and distribution of giant kelp beds has fluctuated greatly during the past 30 years. Kelp canopies have generally declined since1967, when the California Department conducted the first statewide survey documenting the size and distribution of â¦ Though it resembles a tall grass, giant kelp is not a plant. 2006). Description: Thallus of this golden brown canopy kelp may reach a length of 30 m (99 ft). The mass distribution along the fronds of Macrocystis is examined for plants collected from California and New Zealand. A conical, richly branched holdfast (haptera) hosts several stipes, which branch dichotomously into vine-like fronds with blades to ~ 50 cm (20 in) long at regular intervals. Macrocystis integrifolia has the northernmost distribution of the two species, from Alaska to Monterey, California in the low intertidal and subtidal. The vertical distribution pattern of algae was determined using three permanent transects extending from the upper intertidal to the Macrocystis pyrifera belt at zero mean low water (MLW). For example, given year-round suitably low water temperatures, ample nutrients, and protection from wave action, both M. pyrifera and â¦ luxurians J.D.Hooker & Harvey , 1847 Macrocystis luxurians ( J.D.Hooker & Harvey ) J.Agardh , 1848 datasets have provided data to the NBN Atlas for this species.. Browse the list of datasets and find organisations you can join if you are interested in participating in a survey for species like Macrocystis pyrifera (Linnaeus) C.Agardh Macrocystis is the most widely distributed kelp genus in the world, with an amphitropical distribution that spans the west coasts of North and South America and also includes Argentina, South Africa, Australia, New Zealand, and most of the sub-Antarctic islands (Neushul 1971, cited in Hernandez-Carmona et al. California coastline is the home of a wide distribution of the giant kelp, Macrocystis pyrifera. Analysis of fronds classified according to length and condition yields polynomial curves for cumulative mass as a function of distance above the holdfast. M. pyrifera also provides the largest single source of fixed carbon in Southern California and is â¦ The distance between the transects was approximately 50 m. Attaining lengths of up to 50 meters (Hoek et al., 1995), it is among the largest of the marine producers. Distribution: Macrocystis pyrifera is common along the coast of the eastern Pacific Ocean, from Baja California north to southeast Alaska, and is also found in the southern oceans near South America, South Africa, Australia, and New Zealand. Macrocystis tenuifolia Postels & Ruprecht, 1840 Macrocystis pyrifera var. The giant kelp Macrocystis pyrifera and the bull kelp Nereocystis luetkeana are the dominant canopy-forming kelps in this region, and make up the major forests within the MBNMS. Reaching heights of more than 100 feet (30 m), the giant kelp is the largest seaweed and the largest of all marine algae. Concentrations of nutrients in the vicinity of the giant kelp (Macrocystis pyrifera) off San Diego, California, varied seasonally.Surface nitrate concentrations were low for most of the year (usually <1 µM), higher during winter.Nitrate concentrations below 4.5âm depth usually exceeded 1 µM and were highest during spring upwelling, lowest during summer. Abstract.