'{{Short description|Underwater areas highly dense with kelp}} {{ocean habitat topics|image=[[File:Kelp forest.jpg|250]]|caption=Kelp forest}} '''Kelp forests''' are underwater areas with a high density of [[kelp]], which covers a large part of the world's coastlines. Smaller areas of anchored kelp are called '''kelp beds'''. They are recognized as one of the most productive and dynamic [[ecosystem]]s on Earth.<ref name="Mann (1973)">Mann, K.H. 1973. Seaweeds: their productivity and strategy for growth. Science 182: 975-981.</ref><ref>{{Cite journal |last1=Pessarrodona |first1=A|last2=Assis|first2=J|last3=Filbee-Dexter|first3=K|last4=Burrows|first4=M T|last5=Gattuso|first5=J-P|last6=Duarte|first6=C.M.|last7=Krause-Jensen|first7=D|last8=Moore|first8=P.J.|last9=Smale|first9=D.A.|last10=Wernberg |first10=T|date=23 July 2020 |title=Global Seaweed Productivity |journal=Science Advances|volume=8|issue=37 |page=eabn2465|doi=10.1126/sciadv.abn2465 |pmid=36103524|pmc=9473579|hdl=10754/681467|hdl-access=free}}</ref> Although algal kelp forest combined with [[coral reef]]s only cover 0.1% of Earth's total surface, they account for 0.9% of global [[Primary production|primary productivity]].<ref>See Fig. 3 in {{Cite journal |doi=10.3390/soilsystems2040064|doi-access=free|title=Non-Flat Earth Recalibrated for Terrain and Topsoil|year=2018|last1=Blakemore|first1=Robert|journal=Soil Systems|volume=2|issue=4|page=64}}</ref> Kelp forests occur worldwide throughout [[temperate]] and [[polar region|polar]] coastal oceans.<ref name="Mann (1973)" /> In 2007, kelp forests were also discovered in [[tropical]] waters near [[Ecuador]].<ref name="Graham et al. 2007">Graham, M.H., B.P. Kinlan, L.D. Druehl, L.E. Garske, and S. Banks. 2007. Deep-water kelp refugia as potential hotspots of tropical marine diversity and productivity. Proceedings of the National Academy of Sciences 104: 16576-16580.</ref> [[File:Kelp forest distribution map.png|thumb|244px|{{center|Global distribution of kelp forests}}]] {{Quote box |title = |quote = "I can only compare these great aquatic forests...with the terrestrial ones in the intertropical regions. Yet if in any country a forest was destroyed, I do not believe so nearly so many species of animals would perish as would here, from the destruction of kelp. Amidst the leaves of this plant numerous species of fish live, which nowhere else could find food or shelter; with their destruction the many cormorants and other fishing birds, the otters, seals and porpoise, would soon perish also; and lastly, the Fuegian[s]...would...decrease in numbers and perhaps cease to exist. |source = – [[Charles Darwin]], 1 June 1834, Tierra del Fuego, Chile<ref>Darwin, C. 1909. ''The Voyage of the Beagle''. The Harvard Classics Volume 29. New York, USA: P.F. Collier & Son Company.</ref> |align = right |width = 252px |quoted = |salign = right |sstyle = }} Physically formed by brown [[macroalgae]], kelp forests provide a unique habitat for marine organisms<ref>Christie, H., Jørgensen, N.M., Norderhaug, K.M., Waage-Nielsen, E., 2003. Species distribution and habitat exploitation of fauna associated with kelp (Laminaria hyperborea) along the Norwegian coast. Journal of the Marine Biological Association of the UK 83, 687-699.</ref> and are a source for understanding many ecological processes. Over the last century, they have been the focus of extensive research, particularly in [[Trophic dynamics|trophic]] ecology, and continue to provoke important ideas that are relevant beyond this unique ecosystem. For example, kelp forests can influence coastal [[Oceanography|oceanographic]] patterns<ref>Jackson, G.A. and C.D. Winant. 1983. Effect of a kelp forest on coastal currents. Continental Shelf Report 2: 75-80.</ref> and provide many [[ecosystem services]].<ref name="Steneck 2002">Steneck, R.S., M.H. Graham, B.J. Bourque, D. Corbett, [[Jon Erlandson|J.M. Erlandson]], [[James A. Estes|J.A. Estes]] and M.J. Tegner. 2002. Kelp forest ecosystems: biodiversity, stability, resilience and future. Environmental Conservation 29: 436-459.</ref> However, the influence of humans has often contributed to kelp [[forest degradation]]. Of particular concern are the effects of [[overfishing]] nearshore ecosystems, which can release [[herbivore]]s from their normal population regulation and result in the [[overgrazing]] of kelp and other algae.<ref name="Sala1998">Sala, E., C.F. Bourdouresque and M. Harmelin-Vivien. 1998. Fishing, trophic cascades, and the structure of algal assemblages: evaluation of an old but untested paradigm. Oikos 82: 425-439.</ref> This can rapidly result in transitions to [[Urchin barren|barren landscapes]] where relatively few species persist.<ref name="Dayton 1985a">Dayton, P.K. 1985a. Ecology of kelp communities. Annual Review of Ecology and Systematics 16: 215-245.</ref><ref>Norderhaug, K.M., Christie, H., 2009. Sea urchin grazing and kelp re-vegetation in the NE Atlantic. Marine Biology Research 5, 515-528</ref> Already due to the combined effects of [[overfishing]] and [[climate change]],<ref>{{Cite journal |last1=Filbee-Dexter |first1=Karen |last2=Feehan |first2=Colette J. |last3=Scheibling |first3=Robert E. |date=2016-02-03 |title=Large-scale degradation of a kelp ecosystem in an ocean warming hotspot |url=https://www.int-res.com/abstracts/meps/v543/p141-152/ |journal=Marine Ecology Progress Series |language=en |volume=543 |pages=141–152 |doi=10.3354/meps11554 |bibcode=2016MEPS..543..141F |issn=0171-8630}}</ref> kelp forests have all but disappeared in many especially vulnerable places, such as [[Tasmania]]'s east coast and the coast of [[Northern California]].<ref>{{Cite web|last1=Morton|first1=Adam|last2=Cordell|first2=Marni|last3=Fanner|first3=David|last4=Ball|first4=Andy|last5=Evershed|first5=Nick|title=The dead sea: Tasmania's underwater forests disappearing in our lifetime|url=http://www.theguardian.com/environment/ng-interactive/2020/feb/24/the-dead-sea-tasmanias-underwater-forests-disappearing-in-our-lifetime|access-date=2020-10-22|website=the Guardian|language=en}}</ref><ref>{{Cite web|last=Steinbauer|first=James|title=What Will It Take to Bring Back the Kelp Forest? - Bay Nature Magazine|url=https://baynature.org/article/bringing-back-kelp/|access-date=2020-10-22|website=Bay Nature|language=en-US}}</ref> The implementation of [[marine protected areas]] is one management strategy useful for addressing such issues, since it may limit the impacts of fishing and buffer the ecosystem from additive effects of other environmental stressors. == Kelp == {{main|Kelp}} The term [[kelp]] refers to [[marine algae]] belonging to the [[Order (biology)|order]] Laminariales (phylum: [[Ochrophyta]]). Though not considered a taxonomically diverse order, kelps are highly diverse structurally and functionally.<ref name="Steneck 2002"/> The most widely recognized species are the giant kelps (''[[Macrocystis]]'' spp.), although numerous other genera such as ''[[Laminaria]]'', ''[[Ecklonia]]'', ''[[Lessonia (alga)|Lessonia]]'', ''[[Nereocystis]]'', ''[[Alaria (alga)|Alaria]]'', and ''[[Eisenia (alga)|Eisenia]]'' are described. A wide range of sea life uses kelp forests for protection or food, including fish. In the North Pacific kelp forests, particularly [[Sebastidae|rockfish]], and many [[invertebrate]]s, such as [[amphipod]]s, [[shrimp]], [[marine snail]]s, [[bristle worm]]s, and [[brittle star]]s. Many marine mammals and birds are also found, including seals, sea lions, whales, [[sea otter]]s, gulls, terns, [[snowy egret]]s, [[great blue heron]]s, and cormorants, as well as some shore birds.<ref>[http://oceanservice.noaa.gov/facts/kelplives.html Kelp forests provide habitat for a variety of invertebrates, fish, marine mammals, and birds] NOAA. Updated 11 January 2013. Retrieved 15 January 2014.</ref> Frequently considered an [[ecosystem engineer]], kelp provides a physical substrate and habitat for kelp forest communities.<ref>Jones, C.G., J. H. Lawton and M. Shachak. 1997. Positive and negative effects of organisms as physical ecosystem engineers. Ecology 78: 1946-1957.</ref> In algae (kingdom [[Protista]]), the body of an individual organism is known as a [[thallus]] rather than as a plant (kingdom [[Plantae]]). The morphological structure of a kelp thallus is defined by three basic structural units:<ref name="Dayton 1985a"/> * The [[holdfast (biology)|holdfast]] is a root-like mass that anchors the thallus to the sea floor, though unlike true roots it is not responsible for absorbing and delivering nutrients to the rest of the thallus. * The [[Stipe (botany)|stipe]] is analogous to a plant stalk, extending vertically from the holdfast and providing a support framework for other morphological features. * The [[fronds]] are leaf- or blade-like attachments extending from the stipe, sometimes along its full length, and are the sites of nutrient uptake and photosynthetic activity. In addition, many kelp species have [[pneumatocyst]]s, or gas-filled bladders, usually located at the base of fronds near the stipe. These structures provide the necessary buoyancy for kelp to maintain an upright position in the water column. The environmental factors necessary for kelp to survive include hard substrate (usually rock or sand), high nutrients (e.g., nitrogen, phosphorus), and light (minimum annual [[irradiance]] dose > 50 E m⁻²<ref name="Druehl 1981">Druehl, L.D. 1981. The distribution of Laminariales in the North Pacific with reference to environmental influences. Proceedings of the International Congress on Systematic Evolution and Biology 2: 248-256.</ref>). Especially productive kelp forests tend to be associated with areas of significant oceanographic [[upwelling]], a process that delivers cool, nutrient-rich water from depth to the ocean's [[mixed layer|mixed surface layer]].<ref name="Druehl 1981"/> Water flow and turbulence facilitate nutrient assimilation across kelp fronds throughout the water column.<ref>Wheeler, W.N. 1980. Effect of boundary layer transport on the fixation of carbon by the giant kelp ''Macrocystis pyrifera''. Marine Biology 56: 103-110.</ref> Water clarity affects the depth to which sufficient light can be transmitted. In ideal conditions, giant kelp (''Macrocystis'' spp.) can grow as much as 30–60&nbsp;cm vertically per day. Some species, such as ''Nereocystis'', are [[annual plant|annual]]s, while others such as ''Eisenia'' are [[perennial plant|perennial]]s, living for more than 20 years.<ref>Steneck, R.S. and M.N. Dethier. 1994. A functional group approach to the structure of algal-dominated communities. Oikos 69: 476-498.</ref> In perennial kelp forests, maximum growth rates occur during upwelling months (typically spring and summer) and die-backs correspond to reduced nutrient availability, shorter photoperiods, and increased storm frequency.<ref name="Dayton 1985a"/> Kelps are primarily associated with [[temperate]] and [[arctic]] waters worldwide. Of the more dominant genera, ''Laminaria'' is mainly associated with both sides of the [[Atlantic Ocean]] and the coasts of [[China]] and [[Japan]]; ''Ecklonia'' is found in [[Australia]], [[New Zealand]], and [[South Africa]]; and ''Macrocystis'' occurs throughout the northeastern and southeastern [[Pacific Ocean]], [[Southern Ocean]] archipelagos, and in patches around Australia, New Zealand, and South Africa.<ref name="Dayton 1985a"/> The region with the greatest diversity of kelps (>20 species) is the northeastern Pacific, from north of [[San Francisco, California]], to the [[Aleutian Islands]], Alaska. Although kelp forests are unknown in tropical surface waters, a few species of ''Laminaria'' have been known to occur exclusively in tropical deep waters.<ref>Joly, A.B. and E.C. Oliveira Filho. 1967. Two Brazilian ''Laminarias''. Instituto de Pesquisas da Marinha 4: 1-7.</ref><ref>Petrov, J.E., M.V. Suchovejeva and G.V. Avdejev. 1973. New species of the genus ''Laminaria'' from the Philippine Sea. Nov Sistem. Nizch. Rast. 10: 59-61.</ref> This general absence of kelp from the tropics is believed to be mostly due to insufficient nutrient levels associated with warm, [[oligotroph]]ic waters.<ref name="Dayton 1985a"/> One recent study spatially overlaid the requisite physical parameters for kelp with mean oceanographic conditions and produced a model predicting the existence of subsurface kelps throughout the tropics worldwide to depths of {{Convert|200|m|ft|abbr=on}}. For a hotspot in the [[Galapagos Islands]], the local model was improved with fine-scale data and tested; the research team found thriving kelp forests in all eight of their sampled sites, all of which had been predicted by the model, thus validating their approach. This suggests that their global model might actually be fairly accurate, and if so, kelp forests would be prolific in tropical subsurface waters worldwide.<ref name=" Graham et al. 2007"/> The importance of this contribution has been rapidly acknowledged within the scientific community and has prompted an entirely new trajectory of kelp forest research, highlighting the potential for kelp forests to provide marine organisms spatial refuge under climate change and providing possible explanations for evolutionary patterns of kelps worldwide.<ref>Santelices, B. 2007. The discovery of kelp forests in deep-water habitats of tropical regions. Proceedings of the NationalAwan Riak Academy of Sciences 104: 19163-19164.</ref> == Ecosystem architecture == [[File:Rockfish around kelp Monterey Bay Aquarium.jpg|thumb|[[Sebastidae|Rockfish]] swimming around [[Macrocystis pyrifera|giant kelp]]]] [[File:Diver in kelp forest.jpg|thumb|A diver in a [[kelp]] forest off the coast of California]] [[File:Kelp Forest off of Anacapa Island California.jpg|thumb|right|A kelp forest off of the coast of Anacapa Island, California]] [[File:Giantkelp2 300.jpg|thumb|right|[[Giant kelp]] uses gas-filled floats to keep the thallus suspended, allowing the kelp blades near the ocean surface to capture light for photosynthesis.]] The architecture of a kelp forest ecosystem is based on its physical structure, which influences the associated species that define its community structure. Structurally, the ecosystem includes three guilds of kelp and two guilds occupied by other algae:<ref name="Dayton 1985a"/> *Canopy kelps include the largest species and often constitute floating canopies that extend to the ocean surface (e.g., ''Macrocystis'' and ''Alaria''). *Stipitate kelps generally extend a few meters above the sea floor and can grow in dense aggregations (e.g., ''Eisenia'' and ''Ecklonia''). *Prostrate kelps lie near and along the sea floor (e.g., ''Laminaria''). *The [[benthic]] assemblage is composed of other algal species (e.g., filamentous and foliose functional groups, articulated corallines) and sessile organisms along the ocean bottom. *Encrusting coralline algae directly and often extensively cover geologic substrate. Multiple kelp species often co-exist within a forest; the term understory canopy refers to the stipitate and prostrate kelps. For example, a ''Macrocystis'' canopy may extend many meters above the seafloor towards the ocean surface, while an understory of the kelps ''Eisenia'' and ''Pterygophora'' reaches upward only a few meters. Beneath these kelps, a benthic assemblage of foliose red algae may occur. The dense vertical infrastructure with overlying canopy forms a system of microenvironments similar to those observed in a terrestrial forest, with a sunny canopy region, a partially shaded middle, and darkened seafloor.<ref name="Dayton 1985a"/> Each guild has associated organisms, which vary in their levels of dependence on the habitat, and the assemblage of these organisms can vary with kelp morphologies.<ref name="Foster 1985">Foster, M.S. and D.R. Schiel. 1985. The ecology of giant kelp forests in California: a community profile. US Fish and Wildlife Service Report 85: 1-152.</ref><ref name="Graham2004">Graham, M.H. 2004. Effects of local deforestation on the diversity and structure of Southern California giant kelp forest food webs. Ecosystems 7: 341-357.</ref><ref>Fowler-Walker, M.J., B. M. Gillanders, S.D. Connell and A.D. Irving. 2005. Patterns of association between canopy-morphology and understory assemblages across temperate Australia. [[Estuarine, Coastal and Shelf Science]] 63: 133-141.</ref> For example, in California, ''Macrocystis pyrifera'' forests, the [[nudibranch]] ''[[Melibe leonina]]'', and [[skeleton shrimp]] ''Caprella californica'' are closely associated with surface canopies; the kelp perch ''Brachyistius frenatus'', rockfish ''[[Sebastes]]'' spp., and many other fishes are found within the stipitate understory; [[brittle stars]] and turban snails ''[[Tegula (gastropod)|Tegula]]'' spp. are closely associated with the kelp holdfast, while various herbivores, such as sea urchins and abalone, live under the prostrate canopy; many seastars, hydroids, and [[benthic]] fishes live among the benthic assemblages; solitary corals, various [[gastropods]], and [[echinoderms]] live over the encrusting coralline algae.<ref name="Foster 1985"/> In addition, [[pelagic fish]]es and [[marine mammals]] are loosely associated with kelp forests, usually interacting near the edges as they visit to feed on resident organisms. == Trophic ecology == [[File:Seaurchin 300.jpg|thumb|right|Sea urchins like this [[Strongylocentrotus purpuratus|purple sea urchin]] can damage kelp forests by chewing through kelp [[holdfast (biology)|holdfast]]s]] [[File:Mother sea otter with rare twin baby pups (9137174915).jpg|thumb|right|The [[sea otter]] is an important predator of [[sea urchin]]s]] [[File:Calliostoma annulatum.jpg|thumb|right|The jeweled top snail ''[[Calliostoma annulatum]]'' grazing on a blade of giant kelp]] Classic studies in kelp forest ecology have largely focused on trophic interactions (the relationships between organisms and their [[food webs]]), particularly the understanding and top-down trophic processes. Bottom-up processes are generally driven by the abiotic conditions required for primary producers to grow, such as availability of light and nutrients, and the subsequent transfer of energy to consumers at higher trophic levels. For example, the occurrence of kelp is frequently correlated with oceanographic upwelling zones, which provide unusually high concentrations of nutrients to the local environment.<ref>Jackson, G.A. 1977. Nutrients and production of giant kelp, ''Macrocystis pyrifera'', off southern California. Limnology and Oceanography 22: 979-995.</ref><ref name="Dayton1999">Dayton, P.K. M.J. Tegner, P.B. Edwards and K.L. Riser. 1999. Temporal and spatial scales of kelp demography: the role of the oceanographic climate. Ecological Monographs 69: 219-250.</ref> This allows kelp to grow and subsequently support herbivores, which in turn support consumers at higher [[trophic level]]s.<ref name="Carr">Carr, M.H. 1994. Effects of macroalgal dynamics on recruitment of a temperate reef fish. Ecology 75: 1320-1333.</ref> By contrast, in top-down processes, predators limit the biomass of species at lower trophic levels through consumption. In the absence of predation, these lower-level species flourish because resources that support their energetic requirements are not limiting. In a well-studied example from Alaskan kelp forests,<ref name="Estes1995">[[James A. Estes|Estes, J.A.]] and D.O. Duggins. 1995. Sea otters and kelp forests in Alaska: generality and variation in a community ecological paradigm. Ecological Monographs 65: 75-100.</ref> [[sea otters]] (''Enhydra lutris'') control populations of herbivorous [[sea urchins]] through predation. When sea otters are removed from the ecosystem (for example, by human exploitation), urchin populations are released from predatory control and grow dramatically. This leads to increased herbivore pressure on local kelp stands. Deterioration of the kelp itself results in the loss of physical ecosystem structure and subsequently, the loss of other species associated with this habitat. In Alaskan kelp forest ecosystems, sea otters are the [[keystone species]] that mediates this [[trophic cascade]]. In Southern California, kelp forests persist without sea otters and the control of herbivorous urchins is instead mediated by a suite of predators including lobsters and large fishes, such as the [[California sheephead]]. The effect of removing one predatory species in this system differs from Alaska because redundancy exists in the trophic levels and other predatory species can continue to regulate urchins.<ref name="Graham2004"/> However, the removal of multiple predators can effectively release urchins from predator pressure and allow the system to follow trajectories towards kelp forest degradation.<ref name="Pearse&Hines">Pearse, J.S. and A.H. Hines. 1987. Expansion of a central California kelp forest following the mass mortality of sea urchins. Marine Biology 51: 83-91.</ref> Similar examples exist in [[Nova Scotia]],<ref>Scheibiling, R.E. and A.W. Hennigar. 1997. Recurrent outbreaks of disease in sea urchins ''Strongylocentrotus droebachiensis'' in Nova Scotia: evidence for a link with large-scale meteor logic and oceanographic events. Marine Ecology Progress Series 152: 155-165.</ref> South Africa,<ref>Velimirov, B., J.G. Field, C.L. Griffiths and P. Zoutendyk. 1977. The ecology of kelp bed communities in the Benguela upwelling system. Helgoland Marine Research 30: 495-518.</ref> Australia,<ref>Andrew, N.L. 1993. Spatial heterogeneity, sea urchin [[grazing]], and habitat structure on reefs in temperate Australia. Ecology 74: 292-302.</ref> and Chile.<ref>Dayton, P.K. 1985b. The structure and regulation of some South American kelp communities. Ecological Monographs 55: 447-468.</ref> The relative importance of top-down versus bottom-up control in kelp forest ecosystems and the strengths of trophic interactions continue to be the subject of considerable scientific investigation.<ref name="Sala&Graham">Sala, E. and M.H. Graham. 2002. Community-wide distribution of predator-prey interaction strength in kelp forests. Proceedings of the National Academy of Sciences 99: 3678-3683.</ref><ref>Byrnes, J., J.J. Stachowicz, K.M. Hultgren, A.R. Hughes, S.V. Olyarnik and C.S. Thornber. 2006. Predator diversity strengthens trophic cascades in kelp forests by modifying herbivore behavior. Ecology Letters 9: 61-71.</ref><ref name="Halpern2006">Halpern, B.S., K. Cottenie and B.R. Broitman. 2006. Strong top-down control in Southern California kelp forest ecosystems. Science 312: 1230-1232.</ref> The transition from macroalgal (i.e. kelp forest) to denuded landscapes dominated by sea urchins (or ‘[[urchin barrens]]’) is a widespread phenomenon,<ref name ="Steneck 2002"/><ref>Lawrence, J.M. 1975. On the relationships between marine plants and sea urchins. Oceanography and Marine Biology, An Annual Review. 13: 213-286.</ref><ref>Hughes, T.P. 1994. Catastrophes, phase shifts and large-scale degradation of a Caribbean coral reef. Science 265: 1547-1551.</ref><ref>Siversten, K. 2006. Overgrazing of kelp beds along the coast of Norway. Journal of Applied Phycology 18: 599-610.</ref><ref>{{Cite journal |last1=Filbee-Dexter |first1=Karen |last2=Scheibling |first2=Robert E. |date=January 2017 |title=The present is the key to the past: linking regime shifts in kelp beds to the distribution of deep-living sea urchins |url=https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecy.1638 |journal=Ecology |language=en |volume=98 |issue=1 |pages=253–264 |doi=10.1002/ecy.1638 |pmid=28052391 |bibcode=2017Ecol...98..253F |issn=0012-9658}}</ref> often resulting from trophic cascades like those described above; the two phases are regarded as alternative stable states of the ecosystem.<ref name="Dayton1992">Dayton, P.K., M.J. Tegner, P.E. Parnell and P.B. Edwards. 1992. Temporal and spatial patterns of disturbance and recovery in a kelp forest community. Ecological Monographs 62: 421-445.</ref><ref>Pearse, J.S. 2006. Ecological role of purple sea urchins. Science 314: 940-941.</ref><ref>{{Cite journal |last1=Filbee-Dexter |first1=Karen |last2=Scheibling |first2=Robert E. |date=2014-01-09 |title=Sea urchin barrens as alternative stable states of collapsed kelp ecosystems |url=https://www.int-res.com/abstracts/meps/v495/p1-25/ |journal=Marine Ecology Progress Series |language=en |volume=495 |pages=1–25 |doi=10.3354/meps10573 |bibcode=2014MEPS..495....1F |issn=0171-8630}}</ref> The recovery of kelp forests from barren states has been documented following dramatic perturbations, such as urchin disease or large shifts in thermal conditions.<ref name="Pearse&Hines"/><ref>Lafferty, K.D. 2004. Fishing for lobsters indirectly increases epidemics in sea urchins. Ecological Applications 14: 1566-1573.</ref><ref name="Vasquez">Vásquez, J.A., J.M. Alonso Vega and A.H. Buschmann. 2006. Long term variability in the structure of kelp communities in northern Chile and the 1997-98 ENSO. Journal of Applied Phycology 18: 505-519.</ref> Recovery from intermediate states of deterioration is less predictable and depends on a combination of abiotic factors and biotic interactions in each case. Though urchins are usually the dominant herbivores, others with significant interaction strengths include [[starfish|seastars]], [[isopods]], kelp [[crabs]], and [[herbivorous]] fishes.<ref name="Dayton 1985a"/><ref name="Sala&Graham"/> In many cases, these organisms feed on kelp that has been dislodged from substrate and drifts near the ocean floor rather than expend energy searching for intact thalli on which to feed. When sufficient drift kelp is available, herbivorous grazers do not exert pressure on attached thalli; when drift subsidies are unavailable, grazers directly impact the physical structure of the ecosystem.<ref>Cowen, R.K. 1983. The effect of sheephead (''Semicossyphus pulcher'') predation on red sea urchin (''Strongylocentrotus franciscanus'') populations: an experimental analysis. [[Oecologia]] 58: 249-255.</ref><ref name="Ebeling">Ebeling, A.W., D.R. Laur and R.J. Rowley. 1985. Severe storm disturbances and reversal of community structure in a southern California kelp forest. Marine Biology 84: 287-294.</ref> Many studies in Southern California have demonstrated that the availability of drift kelp specifically influences the foraging behavior of sea urchins.<ref name="Dayton 1984">Dayton, P.K. and M.J. Tegner. 1984. Catastrophic storms, El Niño, and patch stability in a southern California kelp community. Science 224: 283-285.</ref><ref>Harrold, C. and D.C. Reed. 1985. Food availability, sea urchin grazing and kelp forest community structure. Ecology 66: 1160-1169.</ref> Drift kelp and kelp-derived particulate matter have also been important in subsidizing adjacent habitats, such as sandy beaches and the rocky intertidal.<ref>Koop, K., R.C. Newell and M.I. Lucas. 1982. Biodegradation and carbon flow based on kelp (''Ecklonia maxima'') debris in a sandy beach microcosm. Marine Ecology Progress Series 7: 315-326.</ref><ref>Bustamante, R.H., G.M. Branch and S. Eekhout. 1995. Maintenance of exceptional intertidal grazer biomass in South Africa: subsidy by subtidal kelps. Ecology 76: 2314-2329.</ref><ref>Kaehler, S., E.A. Pakhomov, R.M. Kalin and S. Davis. 2006. Trophic importance of kelp-derived suspended particulate matter in a through-flow sub-Antarctic system. Marine Ecology Progress Series 316: 17-22.</ref> == Patch dynamics == Another major area of kelp forest research has been directed at understanding the spatial-temporal patterns of kelp patches. Not only do such dynamics affect the physical landscape, but they also affect species that associate with kelp for refuge or foraging activities.<ref name="Foster 1985"/><ref name="Carr"/> Large-scale environmental disturbances have offered important insights concerning mechanisms and ecosystem [[Resilience (ecology)|resilience]]. Examples of environmental disturbances include: *Acute and chronic [[pollution]] events have been shown to impact southern California kelp forests, though the intensity of the impact seems to depend on both the nature of the contaminants and duration of exposure.<ref>Grigg, R.W. and R.S. Kiwala. 1970. Some ecological effects of discharged wastes on marine life. California Department of Fish and Game 56: 145-155.</ref><ref>Stull, J.K. 1989. Contaminants in sediments near a major marine outfall: history, effects and future. OCEANS ’89 Proceedings 2: 481-484.</ref><ref>North, W.J., D.E. James and L.G. Jones. 1993. History of kelp beds (''Macrocystis'') in Orange and San Diego Counties, California. Hydrobiologia 260/261: 277-283.</ref><ref>Tegner, M.J., P.K. Dayton, P.B. Edwards, K.L. Riser, D.B. Chadwick, T.A. Dean and L. Deysher. 1995. Effects of a large sewage spill on a kelp forest community: catastrophe or disturbance? Marine Environmental Research 40: 181-224.</ref><ref>Carpenter, S.R., R.F. Caraco, D.F. Cornell, R.W. Howarth, A.N. Sharpley and V.N. Smith. 1998. Nonpoint pollution of surface waters with phosphorus and nitrogen. Ecological Applications 8: 559-568.</ref> Pollution can include sediment deposition and [[eutrophication]] from sewage, industrial byproducts and contaminants like [[PCBs]] and heavy metals (for example, copper, zinc), runoff of [[organophosphates]] from agricultural areas, anti-fouling chemicals used in harbors and marinas (for example, [[Tributyltin|TBT]] and [[creosote]]) and land-based pathogens like [[fecal coliform bacteria]]. *Catastrophic storms can remove surface kelp canopies through wave activity, but usually leave understory kelps intact; they can also remove urchins when little spatial refuge is available.<ref name="Dayton1992"/><ref name="Ebeling"/> Interspersed canopy clearings create a seascape mosaic where sunlight penetrates deeper into the kelp forest and species that are normally light-limited in the understory can flourish. Similarly, substrate cleared of kelp holdfasts can provide space for other sessile species to establish themselves and occupy the seafloor, sometimes directly competing with juvenile kelp and even inhibiting their settlement.<ref>Kennelly, S.J. 1987. Physical disturbances in an Australian kelp community. I. Temporal effects. Marine Ecology Progress Series 40: 145-153.</ref> * [[El Niño-Southern Oscillation]] (ENSO) events involve the depression of oceanographic thermoclines, severe reductions of nutrient input, and changes in storm patterns.<ref name="Dayton1992"/><ref>McPhaden, M.J. 1999. Genesis and evolution of the 1997-1998 El Niño. Science 283: 950-954.</ref> Stress due to warm water and [[nutrient depletion]] can increase the susceptibility of kelp to storm damage and herbivorous grazing, sometimes even prompting phase shifts to urchin-dominated landscapes.<ref name="Vasquez"/><ref name="Dayton 1984"/><ref>Edwards, M.S. and G. Hernández-Carmona. 2005. Delayed recovery of giant kelp near its southern range limit in the North Pacific following El Niño. Marine Biology 147: 273-279.</ref> In general, oceanographic conditions (that is, water temperature, currents) influence the recruitment success of kelp and its competitors, which clearly affect subsequent species interactions and kelp forest dynamics.<ref name="Dayton1992"/><ref>Duggins, D.O., J.E. Eckman and A.T. Sewell. 1990. Ecology of understory kelp environments. II. Effects of kelps on recruitment of benthic invertebrates. Journal of Experimental Marine Biology and Ecology 143: 27-45.</ref> *Overfishing higher trophic levels that naturally regulate herbivore populations is also recognized as an important stressor in kelp forests.<ref name="Sala1998"/><ref name="Halpern2006"/><ref name="Jackson2001">Jackson, J.B.C, M.X. Kirby, W.H. Berger, K.A. Bjorndal, L.W. Botsford, B.J. Bourque, R.H. Bradbury, R. Cooke, J. [[Jon Erlandson|Erlandson]], [[James A. Estes|J.A. Estes]], T.P. Hughes, S. Kidwell, C.B. Lange, H.S. Lenihan, J.M. Pandolfi, C.H. Peterson, R.S. Steneck, M.J. Tegner and R.R. Warner. 2002. Historical overfishing and the recent collapse of coastal ecosystems. Science 293: 629-638.</ref> As described in the previous section, the drivers and outcomes of trophic cascades are important for understanding spatial-temporal patterns of kelp forests.<ref name="Estes1995"/><ref name="Pearse&Hines"/><ref name="Sala&Graham"/> In addition to ecological monitoring of kelp forests before, during, and after such disturbances, scientists try to tease apart the intricacies of kelp forest dynamics using experimental manipulations. By working on smaller spatial-temporal scales, they can control for the presence or absence of specific biotic and abiotic factors to discover the operative mechanisms. For example, in southern Australia, manipulations of kelp canopy types demonstrated that the relative amount of ''Ecklonia radiata'' in a canopy could be used to predict understory species assemblages; consequently, the proportion of ''E. radiata'' can be used as an indicator of other species occurring in the environment.<ref>Irving, A.D. and S.D. Connell. 2006. Predicting understory structure from the presence and composition of canopies: an assembly rule for marine algae. [[Oecologia]] 148: 491-502.</ref> == Human use == [[File:A diver records kelp growth (9296).jpg|thumb|A diver measures kelp growth]] Kelp forests have been important to human existence for thousands of years.<ref>Simenstad, C.A., [[James A. Estes|J.A. Estes]] and K.W. Kenyon. 1978. Aleuts, sea otters, and alternate stable-state communities. Science 200: 403-411.</ref> Indeed, many now theorise that the first colonisation of the Americas was due to fishing communities following the Pacific kelp forests during the last ice age. One theory contends that the kelp forests that would have stretched from northeast Asia to the American Pacific coast would have provided many benefits to ancient boaters. The kelp forests would have provided many sustenance opportunities, as well as acting as a type of buffer from rough water. Besides these benefits, researchers believe that the kelp forests might have helped early boaters navigate, acting as a type of "kelp highway". Theorists also suggest that the kelp forests would have helped these ancient colonists by providing a stable way of life and preventing them from having to adapt to new ecosystems and develop new survival methods even as they traveled thousands of miles.<ref>Pringle [http://discovermagazine.com/2008/jun/20-did-humans-colonize-the-world-by-boat/article_view?b_start:int=1&-C=. ''Did Humans Colonize the World by Boat?'']</ref> Modern economies are based on [[fisheries]] of kelp-associated species such as [[lobster]] and rockfish. Humans can also harvest kelp directly to feed aquaculture species such as [[abalone]] and to extract the compound [[alginic acid]], which is used in products like toothpaste and antacids.<ref>Gutierrez, A., T. Correa, V. Muñoz, A. Santibañez, R. Marcos, C. Cáceres and A.H. Buschmann. 2006. Farming of the giant kelp ''Macrocystis pyrifera'' in southern Chile for development of novel food products. Journal of Applied Phycology 18: 259-267.</ref><ref>Ortiz, M. and W. Stotz. 2007. Ecological and eco-social models for the introduction of the abalone ''Haliotis discus hannai'' into benthic systems of north-central Chile: sustainability assessment. Aquatic Conservation: Marine and Freshwater Ecosystems 17: 89-105.</ref> Kelp forests are valued for recreational activities such as [[SCUBA diving]] and [[kayaking]]; the industries that support these sports represent one benefit related to the ecosystem and the enjoyment derived from these activities represents another. All of these are examples of [[ecosystem services]] provided specifically by kelp forests. The Monterey Bay aquarium was the first aquarium<ref>[https://www.ksbw.com/article/monterey-bay-aquarium-celebrates-its-37th-birthday/38016805# Monterey Bay Aquarium celebrates its 37th birthday]</ref> to exhibit an alive kelp forest. === As carbon sequesters === Kelp forests grow in rocky places along the shore that are constantly eroding carrying material out to the deep sea. The kelp then sinks to the ocean floor and store the carbon where is it unlikely to be disturbed by human activity.<ref>{{Cite web |last=Hurlimann |first=Sylvia |date=4 July 2019 |title=How Kelp Naturally Combats Global Climate Change |url=https://sitn.hms.harvard.edu/flash/2019/how-kelp-naturally-combats-global-climate-change/ |access-date=21 June 2022 |website=Science in the News}}</ref> Researchers from the [[University of Western Australia]] estimated kelp forest around Australia sequestered 1.3-2.8 teragrams of carbon per year which is 27–34% of the total annual [[blue carbon]] sequestered in the Australian continent by [[tidal marsh]]es, [[mangrove forest]]s and [[Seagrass meadow|seagrass beds]].<ref>{{Cite journal |last1=Filbee-Dexter |first1=Karen |last2=Wernberg |first2=Thomas |date=23 July 2020 |title=Substantial blue carbon in overlooked Australian kelp forests |journal=Scientific Reports|volume=10 |issue=1 |page=12341 |doi=10.1038/s41598-020-69258-7 |pmid=32703990 |pmc=7378163 |bibcode=2020NatSR..1012341F }}</ref> Every year 200 million tons of carbon dioxide are being sequestered by macroalgae such as kelp.<ref>{{Cite journal |last1=Krause-Jensen |first1=Dorte |last2=M. Duarte |first2=Carlos |date=12 September 2016 |title=Substantial role of macroalgae in marine carbon sequestration |url=https://www.nature.com/articles/ngeo2790 |journal=Nature Geoscience|volume=9 |issue=10 |pages=737–742 |doi=10.1038/ngeo2790 |bibcode=2016NatGe...9..737K }}</ref> == Threats and management == [[File:Melibe.2.jpg|thumb|right|The nudibranch ''[[Melibe leonina]]'' on a ''[[Macrocystis]]'' frond (California): Marine protected areas are one way to guard kelp forests as an ecosystem. ]] Given the complexity of kelp forests – their variable structure, geography, and interactions – they pose a considerable challenge to environmental managers. Extrapolating even well-studied trends to the future is difficult because interactions within the ecosystem will change under variable conditions, not all relationships in the ecosystem are understood, and the nonlinear thresholds to transitions are not yet recognized.<ref>Scheffer, M., S. Carpenter, J.A. Foley, C. Folke and B. Walter. 2001. Catastrophic shifts in ecosystems. Nature 413: 591-596.</ref> Major issues of concern include marine pollution and [[water quality]], kelp harvesting and fisheries, [[invasive species]],<ref name="Steneck 2002" /> and [[climate change]].<ref>{{Cite web|url=https://www.abc.net.au/news/2019-02-06/scientists-in-race-to-save-giant-kelp-off-tasmanian-coast/10782410|title=95pc of Tasmania's giant kelp is gone, scientists are in a race to save what's left|last=MacDonald|first=Lucy|date=2019-02-06|website=ABC News|language=en-AU|access-date=2020-02-09}}</ref> The most pressing threat to kelp forest preservation may be the overfishing of coastal ecosystems, which by removing higher trophic levels facilitates their shift to depauperate urchin barrens.<ref name="Sala1998" /> The maintenance of [[biodiversity]] is recognized as a way of generally stabilizing ecosystems and their services through mechanisms such as functional compensation and reduced susceptibility to foreign species invasions.<ref>Frost, T.M., S.R. Carpenter, A.R. Ives, and T.K. Kratz. 1995. "Species compensation and complementarity in ecosystem function." ''In'': C. Jones and J. Lawton, editors. Linking species and ecosystems. Chapman and Hall, London. 387pp.</ref><ref>Tilman, D., C.L. Lehman, and C.E. Bristow. 1998. Diversity-stability relationships: statistical inevitability or ecological consequence? The American Naturalist 151: 277-282.</ref><ref>Stachowicz, J.J., R.B. Whitlatch and R.W. Osman. 1999. Species diversity and invasion resistance in a marine ecosystem. Science 286: 1577-1579.</ref><ref>Elmqvist, T., C. Folke, M. Nyström, G. Peterson, J. Bengtsson, B. Walker and J. Norberg. 2003. Response diversity, ecosystem change and resilience. Frontiers in Ecology and the Environment 1: 488-494.</ref> More recently, the 2022 IPCC report states that kelp and other seaweeds in most regions are undergoing mass mortalities from high temperature extremes and range shifts from warming, as they are stationary and cannot adapt quick enough to deal with the rapidly increasing temperature of the Earth and thus, the ocean.<ref>{{Cite web |title=Climate Change 2022: Impacts, Adaptation and Vulnerability |url=https://www.ipcc.ch/report/ar6/wg2/ |access-date=2022-02-28 |website=www.ipcc.ch |language=en}}</ref> In many places, managers have opted to regulate the harvest of kelp<ref name="Dayton1999"/><ref>Stekoll, M.S., L.E. Deysher and M. Hess. 2006. A remote sensing approach to estimating harvestable kelp biomass. Journal of Applied Phycology 18: 323-334.</ref> and/or the taking of kelp forest species by fisheries.<ref name="Steneck 2002"/><ref name="Jackson2001"/> While these may be effective in one sense, they do not necessarily protect the entirety of the ecosystem. [[Marine protected areas]] (MPAs) offer a unique solution that encompasses not only target species for harvesting, but also the interactions surrounding them and the local environment as a whole.<ref>Allison, G.A., J. Lubchenco and M.H. Carr. 1998. Marine reserves are necessary but not sufficient for marine conservation. Ecological Applications 8: S79-S92.</ref><ref>Airamé, S., J.E. Dugan, K.D. Lafferty, H. Leslie, D.A. MacArdle and R.R. Warner. 2003. Applying ecological criteria to marine reserve design: a case study from the California Channel Islands. Ecological Applications 13: S170-S184.</ref> Direct benefits of MPAs to fisheries (for example, spillover effects) have been well documented around the world.<ref name="Sala1998"/><ref>Bohnsack, J.A. 1998. Application of marine reserves to reef fisheries management. Australian Journal of Ecology 23: 298-304.</ref><ref>Gell, F.R. and C.M. Roberts. 2003. Benefits beyond boundaries: the fishery effects of marine reserves. Trends in Ecology and Evolution 18: 448-455.</ref><ref>Willis, T.J., R.B. Millar and R.C. Babcock. 2003. Protection of exploited fish in temperate regions: high density and biomass of snapper ''Pagrus auratus'' (Sparidae) in northern New Zealand marine reserves. Journal of Applied Ecology 40: 214-227.</ref> Indirect benefits have also been shown for several cases among species such as abalone and fishes in Central California.<ref>Paddack, M.J. and [[James A. Estes|J.A. Estes]]. 2000. Kelp forest fish populations in marine reserves and adjacent exploited areas of Central California. Ecological Applications 10: 855-870.</ref><ref>Rogers-Bennett, L. and J.S. Pearse. 2001. Indirect benefits of marine protected areas for juvenile abalone. Conservation Biology 15: 642-647.</ref> Most importantly, MPAs can be effective at protecting existing kelp forest ecosystems and may also allow for the regeneration of those that have been affected.<ref name="Dayton1992"/><ref>Babcock, R.C., S. Kelly, N.T. Shears, J.W. Walker and T.J. Willis. 1999. Changes in community structure in temperate marine reserves. Marine Ecology Progress Series 189: 125-134.</ref><ref>Halpern, B.S. and R.R. Warner. 2002. Marine reserves have rapid and lasting effects. Ecology Letters 5: 361-366.</ref> === Kelp forest restoration in California === [[File:Fish swarm through the kelp forest.jpg|thumb|Fish [[Shoaling and schooling|swarming]] through a kelp forest]] In the 2010s, Northern California lost 95% of its kelp ecosystems due to marine heatwaves.<ref>{{Cite web|date=2021-03-18|title=Hitting Rock Bottom: The Disappearance of California's Underwater Forests|url=https://andthewest.stanford.edu/2021/hitting-rock-bottom-the-disappearance-of-californias-underwater-forests/|access-date=2021-08-11|website=The Bill Lane Center for the American West, Stanford University|language=en}}</ref><ref>{{Cite web|last=Kerlin|first=Kat|date=2019-10-21|title=California's Crashing Kelp Forest|url=https://climatechange.ucdavis.edu/news/californias-crashing-kelp-forest/|access-date=2021-08-11|website=Science and Climate|language=en-US}}</ref><ref>{{Cite web|last=University of California Santa Cruz|date=2021-03-05|title=The collapse of Northern California kelp forests will be hard to reverse|url=https://phys.org/news/2021-03-collapse-northern-california-kelp-forests.html|access-date=2021-08-11|website=phys.org|language=en}}</ref><ref>{{Cite web|date=2020-05-27|title=5 Reasons to Protect Kelp, the West Coast's Powerhouse Marine Algae|url=https://pew.org/2LXdtHi|access-date=2021-08-11|website=[[Pew Research Center]]}}</ref> Kelp bed recovery efforts in California are primarily focusing on [[sea urchin]] removal,<ref>{{Cite web|last=Foster|first=Michael S|date=2013|title=Kelp Forests in California|url=https://repository.si.edu/bitstream/handle/10088/21627/SCMS39_Lang_10.pdf?sequence=1|website=Smithsonian Contributions to the Marine Sciences}}</ref> both by scuba divers,<ref>{{Cite journal|last1=Williams|first1=Jonathan P.|last2=Claisse|first2=Jeremy T.|last3=Ii|first3=Daniel J. Pondella|last4=Williams|first4=Chelsea M.|last5=Robart|first5=Matthew J.|last6=Scholz|first6=Zoe|last7=Jaco|first7=Erin M.|last8=Ford|first8=Tom|last9=Burdick|first9=Heather|last10=Witting|first10=David|date=2021-04-15|title=Sea urchin mass mortality rapidly restores kelp forest communities|url=https://www.int-res.com/abstracts/meps/v664/p117-131/|journal=Marine Ecology Progress Series|language=en|volume=664|pages=117–131|doi=10.3354/meps13680|bibcode=2021MEPS..664..117W |s2cid=234106934 |issn=0171-8630}}</ref> and by [[sea otter]]s, which are natural predators.<ref>{{Cite web|title=New Findings on Kelp Forest Restoration|url=http://dornsifelive.usc.edu/uscseagrant/new-findings-on-kelp-forest-restoration/|access-date=2021-08-11|website=USC Sea Grant - USC Dana and David Dornsife College of Letters, Arts and Sciences|language=en}}</ref><ref>{{Cite web|title=Saving California's kelp forests|url=https://www.cnn.com/interactive/2021/07/saving-californias-kelp-forests-cte-spc/|access-date=2021-08-11|website=[[CNN]]}}</ref><ref>{{Cite web|date=2021-06-21|title=New Study Finds Hope for Restoration of Kelp Beds and Commercial Fisheries|url=https://polycentric.cpp.edu/2021/06/new-study-finds-hope-for-restoration-of-kelp-beds-and-commercial-fisheries/|access-date=2021-08-11|website=PolyCentric|language=en-US}}</ref><ref>{{Cite web|date=2021|title=Project: Palos Verdes|url=https://sea-trees.org/pages/palos-verdes-kelp|access-date=2021-08-11|website=SeaTrees, by Sustainable Surf|language=en}}</ref><ref>{{Cite web|last=Hohman|first=R|date=2019|title=Sonoma-Mendocino Bull Kelp Recovery Plan, for Greater Farallones National Marine Sanctuary and California Department of Fish & Wildlife|url=https://farallones.org/wp-content/uploads/2019/06/Bull-Kelp-Recovery-Plan-2019.pdf|access-date=2021-08-11|website=Greater Farallones Association}}</ref> A brown alga, ''[[Sargassum horneri]]'', an invasive species first spotted in 2003, has also been a concern.<ref>{{Cite web|date=2017-04-17|title=Marine Invasive Species - Channel Islands National Park|url=https://www.nps.gov/chis/learn/nature/marine-invasive-species.htm|access-date=2021-08-11|website=U.S. National Park Service|language=en}}</ref><ref>{{Cite web|last=Ritchie|first=Erika I|date=2020-09-08|title=An Orange County marine biologist wants to weed the ocean to help kelp grow|url=https://www.ocregister.com/2020/09/08/an-orange-county-marine-biologist-wants-to-weed-the-ocean-to-help-kelp-grow|access-date=2021-08-11|website=[[Orange County Register]]|language=en-US}}</ref> The [[Sunflower sea star]] is an important keystone species which helps control sea urchin abundance, but an outbreak of [[Sea star wasting disease]] and a vulnerability to [[climate change]] has led to its critical endangerment.<ref>{{Cite web |title=Sunflower Sea Star Proposed for Endangered Species Act Protection |url=https://biologicaldiversity.org/w/news/press-releases/sunflower-sea-star-proposed-for-endangered-species-act-protection-2023-03-15/ |access-date=2023-11-30 |website=Center for Biological Diversity |language=en}}</ref> Researchers at the Bodega Marine Laboratory of UC Davis are developing replanting strategies, and volunteers of the Orange County Coastkeeper group are replanting giant kelp.<ref>{{Cite web|last=|date=2021-01-12|title=Kelp: California's Coastal Forests|url=https://marinescience.ucdavis.edu/blog/kelp-californias-coastal-forests|access-date=2021-08-11|website=Coastal and Marine Sciences Institute, UC Davis|language=en}}</ref><ref>{{Cite web|title=Kelp Reforestation Program|url=https://www.coastkeeper.org/restoration/kelp-reforestation-program/|access-date=2021-08-11|website=Orange County Coastkeeper|language=en-US}}</ref> Humboldt State University began cultivating bull kelp in its research farm in 2021.<ref>{{Cite web|date=2021-07-12|title=Kelp is on the Way|url=http://now.humboldt.edu/news/kelp-is-on-the-way/|access-date=2021-08-11|website=Humboldt State Now}}</ref> Research efforts at the state level to prevent kelp forest collapse in California were announced in July 2020.<ref>{{Cite web|last=Leitzell|first=Katherine|date=2020-07-06|title=New research to address kelp forest crisis in California|url=https://caseagrant.ucsd.edu/news/new-research-to-address-kelp-forest-crisis-in-california|access-date=2021-08-11|website=California Sea Grant|language=en}}</ref> At the federal level, H.R. 4458, the Keeping Ecosystems Living and Productive (KELP) Act, introduced July 29, 2021, seeks to establish a new grant program within [[National Oceanic and Atmospheric Administration|NOAA]] for kelp forest restoration.<ref>{{Cite web|last=Bittenbender|first=Steve|date=2021-08-10|title=Huffman-sponsored bill seeks grant funding to restore kelp forests|url=https://www.seafoodsource.com/news/environment-sustainability/huffman-sponsored-bill-seeks-grant-funding-to-restore-kelp-forests|access-date=2021-08-11|website=SeafoodSource}}</ref> == Global Conservation Efforts == The [[United Nations Environment Programme]] Norwegian Blue Forests Network 2023 report titled 'Into the Blue: Securing a Sustainable Future for Kelp Forests' documents a global decline in kelp forests, with an annual reduction rate of 1.8%. Over the past 50 years, 40-60% of these [[Ecosystem|ecosystems]] have degraded due to factors such as climate change, poor water quality, and [[overfishing]]. The report underscores the urgency of implementing global conservation efforts and emphasizes the need for international cooperation to adopt area-based management strategies. These strategies aim to mitigate the aforementioned impacts and enhance the resilience and sustainability of kelp forests.<ref name=":0">United Nations Environment Programme, & Norwegian Blue Forests Network (2023). ''Into the Blue: Securing a Sustainable Future for Kelp Forests''. <nowiki>https://wedocs.unep.org/20.500.11822/42255</nowiki>.</ref> Kelp forest restoration, practiced in 16 countries over 300 years, has gained momentum, particularly from 2009 to 2019, involving diverse societal sectors such as academia, governments, and businesses. Large-scale restoration successes demonstrate its feasibility, with the best outcomes often near existing kelp forests, emphasizing the importance of preventing their decline. However, challenges persist, including the need for cost-effective methods, funding mechanisms, and adaptations to climate change. This restoration work not only supports [[Ecology|ecological]] recovery but also offers significant social and economic benefits, aligning with the [[Sustainable Development Goals|United Nations Sustainable Development Goals]] (SDGs), and underscores the importance of multi-sector collaboration.<ref name=":0" />{{Rp|page=135}} NIGGER ==See also== * [[Aquaculture of giant kelp]] {{clear}} == References == {{reflist|32em}} == External links == {{Commons category|Kelp forests}} *{{cite web|url=http://bonita.mbnms.nos.noaa.gov/sitechar/kelp.html |website=noaa.gov|title=Kelp Forest & Rocky Subtidal Habitats|archive-url=https://web.archive.org/web/20070322210905/http://bonita.mbnms.nos.noaa.gov/sitechar/kelp.html|archive-date=2007-03-22}} *{{cite web|url=http://www.kelpwatch.tas.gov.au/ |website=tas.gov.au|title=Kelp Watch|publisher= Department of Primary Industries, Water & Environment |location=[[Tasmania]], [[Australia]]|archive-url=https://web.archive.org/web/20041204200449/http://www.kelpwatch.tas.gov.au/|archive-date=2004-12-04}} Excellent general information on kelp forests, as well as specific information on Tasmanian kelp forests. *{{cite web|url=http://www.mbayaq.org/efc/efc_hp/hp_kelp_cam.asp |website=mbayaq.org|title=Monterey Bay Aquarium Kelp Cam|publisher=[[Monterey Bay Aquarium]]|archive-url=https://web.archive.org/web/19991128010927/http://www.mbayaq.org/efc/efc_hp/hp_kelp_cam.asp|archive-date=1999-11-28}} Watch a live feed from the kelp forest exhibit. {{aquatic ecosystem topics|expanded=marine}} {{Biomes}} {{Authority control}} [[Category:Aquatic ecology]] [[Category:Fishing industry]] [[Category:Brown algae]]'