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Kelp Forests Unit One CINMS Kelp Forests Lesson Objectives: Students will be able to do the following: • Identify the parts of a kelp and explain their function • Compare and contrast the components of the kelp forest with a terrestrial forest • Describe one monitoring technique used within the kelp forest Key concepts: algae, blade, stipe, holdfast, alternation of generations, sporophyte, seasonality, ecological interdependence, monitoring Kelp Overview Kelps belong to a the blades, their serrated edges help group of to increase water mixing. This drives photosynthetic more nutrients past the kelp plants. organisms known as These nutrients are then absorbed algae. Algae range in by all parts of the kelp. Kelps also size from microscopic single celled need sunlight for photosynthesis. diatoms to large brown kelps. Kelps Clear water allows various are characterized by three main wavelengths of sunlight to penetrate parts: blades, stipes, and to lower depths. Almost all of these holdfasts. The blades are similar to wavelengths of light can be used for the leaves of land plants. They are photosynthesis in the blades. The the photosynthetic factories of the blades are kept near the surface by kelp. It is here that energy from tiny floats. These hollow gas filled sunlight and nutrients from the water bladders are called pneumatocysts. are combined to produce food. Kelp blades also allow Stipes of kelps look like the stems of photosynthesis on both their top and plants, but they do not perform bottom surfaces for maximum food nutrient transport functions like the production. stems of plants. Their main function is to provide support for the kelp blades. The holdfasts, similar in appearance to the roots of land plants, help to anchor the kelp on hard surfaces. Although kelps resemble land plants, they are uniquely adapted to life in cool, clear, moving water. They depend on moving water to provide a steady supply of nutrients for photosynthesis. As water flows by ©Project Oceanography 21 Spring 2002 Unit One CINMS Kelps are designed up to ten years, but the to reproduce in water blades or fronds only through a complex last for a few months. As process known as the blades are torn from alternation of the plants by wave generations. In this action, they begin to process, the large kelp forms make decay. This decayed spores or cells. These spores are material helps recycle released into the water where they nutrients through the system. As the are dispersed. Under the right cycle of reproduction continues, the conditions, these spores develop into kelp plants form thick forest areas. microscopic male and female stages. When a male sperm fertilizes a These forests are found along the female egg, it makes a plant that rocky shores of South America, produces spores. This tiny plant, South Africa, southern Australia, and called a sporophyte, anchors itself to the western coast of North America. the bottom using its holdfast. As it There are many different kinds of grows, it begins to split. kelps and over 20 different species This growth center is are found in California alone. We will called the apical be taking a closer look at some of meristem. When it splits the more common kelps found along each part of it becomes a the California coast. These include blade or a stipe. This the giant kelp (Macrocystis pyrifera), kelp continues to grow oarweed (Laminaria setchellii), bull until it becomes a giant plant that kelp (Nereocystis luetkeana), and produces spores. The cycle begins featherboa (Egregia menziesii). again. The kelp plants may grow for Characteristics of Kelp Forests Kelp forests have some The forest layers help describe this characteristics in complex ecosystem. The uppermost common with forests layer of the kelp forest is called the found on land. They canopy. Along the California coast, are complex the giant kelp is the main algae ecosystems that found in this layer. Among the fronds support many in the kelp canopy live bryozoans, interconnected food hydroids, mysids, amphipods, webs. They provide a variety of isopods, crabs, snails, nudibranchs, habitats for animals at all trophic and juvenile fish of all sorts. Some of levels. They can be divided into these animals feed directly on the layers including the canopy, kelp and are capable of considerable understory, and forest floor. They damage if not kept in control. progress through seasonal cycles. Controlling them are the predatory fish usually found in the mid-level of ©Project Oceanography 22 Spring 2002 Unit One CINMS the forest. Kelp surfperch, pipefish, and nutrients change with natural clingfish, tubesnouts, and giant cycles. The spring season begins as kelpfish are active March winds blow surface waters predators here. offshore. This creates upwelling as Kelp bass and nutrient-rich waters are brought up various rockfish from the depths. At the same time, often prey on the days are lengthening. More sunlight smaller fish. Kelp increases kelp growth. The kelps crabs and kelp snails feed among continue to grow rapidly until blades in the canopy and often fall summer. In the top layers, long days prey to seabirds. The density of kelp and cool nutrient-rich water create fronds in the canopy affects the the perfect environment for amount of light reaching the bottom phytoplankton. These ocean and so determines the types and producers become abundant abundance of algae on the reef. and feed many animals living in this area. As the canopy The understory lies below the thickens, light is cut off to the lower canopy. This layer has algae of layers. Growth at these levels begins medium height much to slow. As fall approaches, wind like the bushes and directions change. This stops the shrubs of the land upwelling of nutrients. The lack of forest. It also supports a nutrients and sunlight slow the variety of food webs. growth of the forest. The kelp plants These food webs can become weakened and begin to thin. be found in open water The dead blades or kelp shed are pathways, on reef tops, or in cracks torn apart by winter storms. Animals and crevices. Shorter kelp varieties growing on the kelp drift are swept such as oarweed and featherboa are away with the dying fronds. characteristic of this layer. The forest Holdfasts also begin to weaken and floor is the bottom layer. It includes loosen. They roll about driven by the the substrate and benthic moving water. The forest creatures. In the kelp forest, this becomes sparse as winter layer contains many animals. Here progresses. This allows the tunicates, sponges, and anemones sunlight to again penetrate are abundant. to lower levels. As the months pass, days grow The kelp forests progress through longer and winds become favorable. seasons as the amounts of sunlight A new spring season begins. Kelp Forest Monitoring Long-term monitoring programs scientists are better able to provide information about changes in understand the ecological impacts to ecosystem health over long periods long-lived species, the effects of of time. Through these studies, natural cycles that take place ©Project Oceanography 23 Spring 2002 Unit One CINMS infrequently, and human impacts that are more widely dispersed such as change gradually over many years. abalone. A quadrat, in this case, is One such monitoring program was one square meter of designed and supported by the space enclosed by PVC Channel Islands National Park, pipe. To identify the Channel Islands National Marine sample areas, Sanctuary and the California quadrats are laid systematically (with Department of Fish and Game. This a random starting point) along a kelp forest monitoring program was transect. This transect is a line conducted using a identified by a 100 meter tape broad assortment measure. Band transects are larger of animals in a sample areas created using a PVC wide range of pole and a shorter tape measure. habitats. Scientists These band transects are laid looked for sample perpendicular to the main transect. organisms that represented a variety As with the quadrats, selected of trophic levels and life strategies. species are counted along these They included animals of various band transects. Roving fish counts reproductive types such as those are used to monitor all that bud or those that develop from the fish sited within ten fertilized eggs. They also included meters of the transect animals that live attached to the line. These fish are substrate and those that move freely. identified, counted, and Researchers then chose sampling recorded. Additional monitoring sites that represented various techniques include larval recruitment habitats. Once sampling species and platforms, videotapes, and water sites were determined, management quality measurements. personnel designed a cost effective monitoring plan that could be carried Special technology is needed to out by trained volunteers supplied conduct surveys underwater. These with appropriate technology. This include self-contained underwater monitoring plan included using breathing apparatus (SCUBA), quadrats, band transects, and roving surface supplied air, wet suits, and fish counts. dry suits. SCUBA gear allows the diver to move about freely Quadrats are underwater, but limits the amount of used to collect time that the diver can stay density underwater without information on resurfacing. species that have Surface supplied relatively dense air reaches the populations such as algae, sea diver through a urchins, and some sea stars. Band breathing line. This transects are designed to collect line provides a density information on species that continuous source of oxygen and ©Project Oceanography 24 Spring 2002 Unit One CINMS can lengthen the amount of time that By incorporating these and other a diver can spend underwater. Other techniques, the CINP and CINMS lines allow direct communication with staff and many other stakeholders the crew on deck. Dry suits extend are able to collect information that the time divers can remain in colder will help us to better understand this water.
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