Kelp forest

Kelp forests are underwater areas with a high density of kelp. They are recognized as one of the most productive and dynamic ecosystems on Earth.[1] Smaller areas of anchored kelp are called kelp beds.

Kelp forest distribution map
Global distribution of kelp that locally form forests.

Kelp forests occur worldwide throughout temperate and polar coastal oceans.[1] In 2007, kelp forests were also discovered in tropical waters near Ecuador.[3]

Physically formed by brown macroalgae, kelp forests provide a unique, three-dimensional habitat for marine organisms[4] and are a source for understanding many ecological processes. Over the last century, they have been the focus of extensive research, particularly in trophic ecology, and continue to provoke important ideas that are relevant beyond this unique ecosystem. For example, kelp forests can influence coastal oceanographic patterns[5] and provide many ecosystem services.[6]

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 herbivores from their normal population regulation and result in the overgrazing of kelp and other algae.[7] This can rapidly result in transitions to barren landscapes where relatively few species persist.[8][9] 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.


The term kelp refers to marine algae belonging to the order Laminariales (phylum: Heterokontophyta). Though not considered a taxonomically diverse order, kelps are highly diverse structurally and functionally.[6] The most widely recognized species are the giant kelps (Macrocystis spp.), although numerous other genera such as Laminaria, Ecklonia, Lessonia, Alaria, and 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 rockfish, and many invertebrates, such as amphipods, shrimp, marine snails, bristle worms, and brittle stars. Many marine mammals and birds are also found, including seals, sea lions, whales, sea otters, gulls, terns, snowy egrets, great blue herons, and cormorants, as well as some shore birds.[10]

Frequently considered an ecosystem engineer, kelp provides a physical substrate and habitat for kelp forest communities.[11] 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:[8]

  • The 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 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 pneumatocysts, 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[12]). 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 surface layer.[12] Water flow and turbulence facilitate nutrient assimilation across kelp fronds throughout the water column.[13] 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 cm vertically per day. Some species, such as Nereocystis, are annuals, while others such as Eisenia are perennials, living for more than 20 years.[14] 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.[8]

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.[8] 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.[15][16] This general absence of kelp from the tropics is believed to be mostly due to insufficient nutrient levels associated with warm, oligotrophic waters.[8] One recent study spatially overlaid the requisite physical parameters for kelp with mean oceanographic conditions has produced a model predicting the existence of subsurface kelps throughout the tropics worldwide to depths of 200 m. 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 validated 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.[3] The importance of this contribution has been rapidly acknowledged within the scientific community and has prompted an entirely new trajectory of kelp forest research, particularly emphasizing the potential for a spatial refuge from climate change also the explanations to evolutionary patterns of kelps worldwide.[17]

Ecosystem architecture

Rockfish around kelp Monterey Bay Aquarium
Rockfish swimming around giant kelp
Diver in kelp forest
A diver in a kelp forest off the coast of California
Kelp Forest off of Anacapa Island California
A kelp forest off of the coast of Anacapa Island, California
Giantkelp2 300
Giant kelp uses gas-filled floats to keep the plant 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:[8]

  • 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.[8] 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.[18][19][20] 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 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.[18] In addition, pelagic fishes and marine mammals are loosely associated with kelp forests, usually interacting near the edges as they visit to feed on resident organisms.

Trophic ecology

Seaurchin 300
Sea urchins like this purple sea urchin can damage kelp forests by chewing through kelp holdfasts
Mother sea otter with rare twin baby pups (9137174915)
The sea otter is an important predator of sea urchins.
Calliostoma annulatum
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.[21][22] This allows kelp to grow and subsequently support herbivores, which in turn support consumers at higher trophic levels.[23] 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,[24] 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.[19] However, the removal of multiple predators can effectively release urchins from predator pressure and allow the system to follow trajectories towards kelp forest degradation.[25] Similar examples exist in Nova Scotia,[26] South Africa,[27] Australia[28] and Chile.[29] 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.[30][31][32]

The transition from macroalgal (i.e. kelp forest) to denuded landscapes dominated by sea urchins (or ‘urchin barrens’) is a widespread phenomenon,[6][33][34][35] often resulting from trophic cascades like those described above; the two phases are regarded as alternative stable states of the ecosystem.[36][37] The recovery of kelp forests from barren states has been documented following dramatic perturbations, such as urchin disease or large shifts in thermal conditions.[25][38][39] 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 seastars, isopods, kelp crabs, and herbivorous fishes.[8][30] 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 plants; when drift subsidies are unavailable, grazers directly impact the physical structure of the ecosystem.[40][41] Many studies in Southern California have demonstrated that the availability of drift kelp specifically influences the foraging behavior of sea urchins.[42][43] Drift kelp and kelp-derived particulate matter have also been important in subsidizing adjacent habitats, such as sandy beaches and the rocky intertidal.[44][45][46]

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.[18][23] Large-scale environmental disturbances have offered important insights concerning mechanisms and ecosystem 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.[47][48][49][50][51] 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, 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.[36][41] 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.[52]
  • El Niño-Southern Oscillation (ENSO) events involve the depression of oceanographic thermoclines, severe reductions of nutrient input, and changes in storm patterns.[36][53] 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.[39][42][54] 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.[36][55]
  • Overfishing higher trophic levels that naturally regulate herbivore populations is also recognized as an important stressor in kelp forests.[7][32][56] As described in the previous section, the drivers and outcomes of trophic cascades are important for understanding spatial-temporal patterns of kelp forests.[24][25][30]

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.[57]

Human use

Kelp forests have been important to human existence for thousands of years.[58] 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.[59] 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.[60][61] 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.

Threats and management

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.[62] With respect to kelp forests, major issues of concern include marine pollution and water quality, kelp harvesting and fisheries, invasive species, and climate change.[6] 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.[7] 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.[63][64][65][66]

In many places, managers have opted to regulate the harvest of kelp[22][67] and/or the taking of kelp forest species by fisheries.[6][56] 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.[68][69] Direct benefits of MPAs to fisheries (for example, spillover effects) have been well documented around the world.[7][70][71][72] Indirect benefits have also been shown for several cases among species such as abalone and fishes in Central California.[73][74] 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.[36][75][76]


  1. ^ a b Mann, K.H. 1973. Seaweeds: their productivity and strategy for growth. Science 182: 975-981.
  2. ^ Darwin, C. 1909. The Voyage of the Beagle. The Harvard Classics Volume 29. New York, USA: P.F. Collier & Son Company.
  3. ^ a b 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.
  4. ^ 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.
  5. ^ Jackson, G.A. and C.D. Winant. 1983. Effect of a kelp forest on coastal currents. Continental Shelf Report 2: 75-80.
  6. ^ a b c d e Steneck, R.S., M.H. Graham, B.J. Bourque, D. Corbett, J.M. Erlandson, J.A. Estes and M.J. Tegner. 2002. Kelp forest ecosystems: biodiversity, stability, resilience and future. Environmental Conservation 29: 436-459.
  7. ^ a b c d 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.
  8. ^ a b c d e f g h Dayton, P.K. 1985a. Ecology of kelp communities. Annual Review of Ecology and Systematics 16: 215-245.
  9. ^ Norderhaug, K.M., Christie, H., 2009. Sea urchin grazing and kelp re-vegetation in the NE Atlantic. Marine Biology Research 5, 515-528
  10. ^ Kelp forests provide habitat for a variety of invertebrates, fish, marine mammals, and birds NOAA. Updated 11 January 2013. Retrieved 15 January 2014.
  11. ^ Jones, C.G., J. H. Lawton and M. Shachak. 1997. Positive and negative effects of organisms as physical ecosystem engineers. Ecology 78: 1946-1957.
  12. ^ a b 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.
  13. ^ 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.
  14. ^ Steneck, R.S. and M.N. Dethier. 1994. A functional group approach to the structure of algal-dominated communities. Oikos 69: 476-498.
  15. ^ Joly, A.B. and E.C. Oliveira Filho. 1967. Two Brazilian Laminarias. Instituto de Pesquisas da Marinha 4: 1-7.
  16. ^ Petrov, J.E., M.V. Suchovejeva and G.V. Avdejev. 1973. New species of the genus Laminaria from the Philippines Sea. Nov Sistem. Nizch. Rast. 10: 59-61.
  17. ^ 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.
  18. ^ a b c 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.
  19. ^ a b 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.
  20. ^ 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.
  21. ^ Jackson, G.A. 1977. Nutrients and production of giant kelp, Macrocystis pyrifera, off southern California. Limnology and Oceanography 22: 979-995.
  22. ^ a b 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.
  23. ^ a b Carr, M.H. 1994. Effects of macroalgal dynamics on recruitment of a temperate reef fish. Ecology 75: 1320-1333.
  24. ^ a b 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.
  25. ^ a b c 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.
  26. ^ 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.
  27. ^ 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.
  28. ^ Andrew, N.L. 1993. Spatial heterogeneity, sea urchin grazing, and habitat structure on reefs in temperate Australia. Ecology 74: 292-302.
  29. ^ Dayton, P.K. 1985b. The structure and regulation of some South American kelp communities. Ecological Monographs 55: 447-468.
  30. ^ a b c 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.
  31. ^ 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.
  32. ^ a b Halpern, B.S., K. Cottenie and B.R. Broitman. 2006. Strong top-down control in Southern California kelp forest ecosystems. Science 312: 1230-1232.
  33. ^ Lawrence, J.M. 1975. On the relationships between marine plants and sea urchins. Oceanography and Marine Biology, An Annual Review. 13: 213-286.
  34. ^ Hughes, T.P. 1994. Catastrophes, phase shifts and large-scale degradation of a Caribbean coral reef. Science 265: 1547-1551.
  35. ^ Siversten, K. 2006. Overgrazing of kelp beds along the coast of Norway. Journal of Applied Phycology 18: 599-610.
  36. ^ a b c d e 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.
  37. ^ Pearse, J.S. 2006. Ecological role of purple sea urchins. Science 314: 940-941.
  38. ^ Lafferty, K.D. 2004. Fishing for lobsters indirectly increases epidemics in sea urchins. Ecological Applications 14: 1566-1573.
  39. ^ a b 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.
  40. ^ 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.
  41. ^ a b 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.
  42. ^ a b 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.
  43. ^ Harrold, C. and D.C. Reed. 1985. Food availability, sea urchin grazing and kelp forest community structure. Ecology 66: 1160-1169.
  44. ^ 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.
  45. ^ 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.
  46. ^ 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.
  47. ^ 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.
  48. ^ Stull, J.K. 1989. Contaminants in sediments near a major marine outfall: history, effects and future. OCEANS ’89 Proceedings 2: 481-484.
  49. ^ 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.
  50. ^ 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.
  51. ^ 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.
  52. ^ Kennelly, S.J. 1987. Physical disturbances in an Australian kelp community. I. Temporal effects. Marine Ecology Progress Series 40: 145-153.
  53. ^ McPhaden, M.J. 1999. Genesis and evolution of the 1997-1998 El Niño. Science 283: 950-954.
  54. ^ 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.
  55. ^ 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.
  56. ^ a b 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. Erlandson, 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.
  57. ^ 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.
  58. ^ Simenstad, C.A., J.A. Estes and K.W. Kenyon. 1978. Aleuts, sea otters, and alternate stable-state communities. Science 200: 403-411.
  59. ^ Pringle Did Humans Colonize the World by Boat?
  60. ^ 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.
  61. ^ 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.
  62. ^ Scheffer, M., S. Carpenter, J.A. Foley, C. Folke and B. Walter. 2001. Catastrophic shifts in ecosystems. Nature 413: 591-596.
  63. ^ 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.
  64. ^ Tilman, D., C.L. Lehman, and C.E. Bristow. 1998. Diversity-stability relationships: statistical inevitability or ecological consequence? The American Naturalist 151: 277-282.
  65. ^ Stachowicz, J.J., R.B. Whitlatch and R.W. Osman. 1999. Species diversity and invasion resistance in a marine ecosystem. Science 286: 1577-1579.
  66. ^ 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.
  67. ^ 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.
  68. ^ 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.
  69. ^ 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.
  70. ^ Bohnsack, J.A. 1998. Application of marine reserves to reef fisheries management. Australian Journal of Ecology 23: 298-304.
  71. ^ 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.
  72. ^ 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.
  73. ^ Paddack, M.J. and J.A. Estes. 2000. Kelp forest fish populations in marine reserves and adjacent exploited areas of Central California. Ecological Applications 10: 855-870.
  74. ^ Rogers-Bennett, L. and J.S. Pearse. 2001. Indirect benefits of marine protected areas for juvenile abalone. Conservation Biology 15: 642-647.
  75. ^ 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.
  76. ^ Halpern, B.S. and R.R. Warner. 2002. Marine reserves have rapid and lasting effects. Ecology Letters 5: 361-366.

External links

  • "Kelp Forest & Rocky Subtidal Habitats".
  • "Kelp Watch". Tasmania, Australia: Department of Primary Industries, Water & Environment. Excellent general information on kelp forests, as well as specific information on Tasmanian kelp forests.
  • "Monterey Bay Aquarium Kelp Cam". Monterey Bay Aquarium. Watch a live feed from the kelp forest exhibit.
Bidenichthys beeblebroxi

Bidenichthys beeblebroxi is a species of common reef fish of the Bythitidae family, and one of three species in the genus Bidenichthys. The species is found in the coastal waters off North Island and northern South Island, New Zealand. It is a common, uniformly gray-brown fish, ranging from SL 6.5–9.5 centimetres (2 1⁄2–3 3⁄4 in) long in one study, found in holes beneath rocks and boulders in kelp forest and other reef habitats from the surface down to depths of 30 metres (98 ft). The species was described by Paulin in 1995.The species was named after the character Zaphod Beeblebrox in Douglas Adams' The Hitchhiker's Guide to the Galaxy.The common names gray or grey brotula and orange cuskeel were used to describe Bidenichthys consobrinus (F. W. Hutton, 1876) prior to Paulin's 1995 redescription of B. consobrinus and description of B. beeblebroxi, in which Paulin referred to "the common grey brotula, here described as a new species [B. beeblebroxi], and Hutton's 'consobrinus'...".

Carmel Pinnacles State Marine Reserve

Carmel Pinnacles State Marine Reserve (SMR) is a marine protected area in Carmel Bay including a unique underwater pinnacle formation with adjacent kelp forest, submarine canyon head, and surfgrass. Carmel Bay is adjacent to the city of Carmel-by-the-Sea and is near Monterey, on California’s central coast.

Cascade effect (ecology)

An ecological cascade effect is a series of secondary extinctions that is triggered by the primary extinction of a key species in an ecosystem. Secondary extinctions are likely to occur when the threatened species are: dependent on a few specific food sources, mutualistic (dependent on the key species in some way), or forced to coexist with an invasive species that is introduced to the ecosystem. Species introductions to a foreign ecosystem can often devastate entire communities, and even entire ecosystems. These exotic species monopolize the ecosystem's resources, and since they have no natural predators to decrease their growth, they are able to increase indefinitely. Olsen et al. showed that exotic species have caused lake and estuary ecosystems to go through cascade effects due to loss of algae, crayfish, mollusks, fish, amphibians, and birds. However, the principal cause of cascade effects is the loss of top predators as the key species. As a result of this loss, a dramatic increase (ecological release) of prey species occurs. The prey is then able to overexploit its own food resources, until the population numbers decrease in abundance, which can lead to extinction. When the prey's food resources disappear, they starve and may go extinct as well. If the prey species is herbivorous, then their initial release and exploitation of the plants may result in a loss of plant biodiversity in the area. If other organisms in the ecosystem also depend upon these plants as food resources, then these species may go extinct as well. An example of the cascade effect caused by the loss of a top predator is apparent in tropical forests. When hunters cause local extinctions of top predators, the predators' prey's population numbers increase, causing an overexploitation of a food resource and a cascade effect of species loss. Recent studies have been performed on approaches to mitigate extinction cascades in food-web networks.

Ecological extinction

Ecological extinction is "the reduction of a species to such low abundance that, although it is still present in the community, it no longer interacts significantly with other species".Ecological extinction stands out because it is the interaction ecology of a species that is important for conservation work. They state that "unless the species interacts significantly with other species in the community (e.g. it is an important predator, competitor, symbiont, mutualist, or prey) its loss may result in little to no adjustment to the abundance and population structure of other species".This view stems from the neutral model of communities that assumes there is little to no interaction within species unless otherwise proven.

Estes, Duggins, and Rathburn (1989) recognize two other distinct types of extinction:

Global extinction is defined as "the ubiquitous disappearance of a species".

Local extinction is characterized by "the disappearance of a species from part of its natural range".

Graus nigra

Graus nigra is a species of sea chub endemic to the Pacific waters off the coast of Chile. This species grows to a length of 64.6 centimetres (25.4 in) TL. It is also popular as a game fish. This species is the only known member of its genus, and is known locally as vieja negra (meaning “old black” in Spanish).


Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera.Kelp grows in "underwater forests" (kelp forests) in shallow oceans, and is thought to have appeared in the Miocene, 23 to 5 million years ago. The organisms require nutrient-rich water with temperatures between 6 and 14 °C (43 and 57 °F). They are known for their high growth rate—the genera Macrocystis and Nereocystis can grow as fast as half a metre a day, ultimately reaching 30 to 80 metres (100 to 260 ft).Through the 19th century, the word "kelp" was closely associated with seaweeds that could be burned to obtain soda ash (primarily sodium carbonate). The seaweeds used included species from both the orders Laminariales and Fucales. The word "kelp" was also used directly to refer to these processed ashes.

Lovers Point State Marine Reserve

Lovers Point State Marine Reserve (SMR) is one of four small marine protected areas located near the cities of Monterey and Pacific Grove, at the southern end of Monterey Bay on California’s central coast. The four MPAs together encompass 2.96 square miles (7.7 km2). The SMR protects all marine life within its boundaries. Fishing and take of all living marine resources is prohibited.

Monterey Bay Aquarium

Monterey Bay Aquarium is a nonprofit public aquarium in Monterey, California. Known for its regional focus on the marine habitats of Monterey Bay, it was the first to exhibit a living kelp forest when it opened in October 1984. Its biologists have pioneered the animal husbandry of jellyfish and it was the first to successfully care for and display a great white shark. The organization's research and conservation efforts also focus on sea otters, various birds, and tunas. Seafood Watch, a sustainable seafood advisory list published by the aquarium beginning in 1999, has influenced the discussion surrounding sustainable seafood.

Early proposals to build a public aquarium in Monterey County were not successful until a group of four marine biologists affiliated with Stanford University revisited the concept in the late-1970s. Monterey Bay Aquarium was built at the site of a defunct sardine cannery and has been recognized for its architectural achievements by the American Institute of Architects. Along with its architecture, the aquarium has won numerous awards for its exhibition of marine life, ocean conservation efforts, and educational programs.

Monterey Bay Aquarium receives around two million visitors each year. It led to the revitalization of Cannery Row, and produces hundreds of millions of dollars for the economy of Monterey County. In addition to being featured in two PBS Nature documentaries, the aquarium has appeared in film and television productions.

National Aquarium (Baltimore)

The National Aquarium - also known as National Aquarium in Baltimore and formerly known as Baltimore Aquarium - is a non-profit public aquarium located at 501 East Pratt Street on Pier 3 in the Inner Harbor area of downtown Baltimore, Maryland in the United States. Constructed during a period of urban renewal in Baltimore, the aquarium opened on August 8, 1981. The aquarium has an annual attendance of 1.5 million visitors and is the largest tourism attraction in the State of Maryland. The Aquarium holds more than 2,200,000 US gallons (8,300,000 l) of water, and has more than 17,000 specimens representing over 750 species. In 2003, the National Aquarium and the much older independent National Aquarium in Washington joined as one National Aquarium with two sites until 2013. The National Aquarium's mission is to inspire conservation of the world's aquatic treasures. The aquarium's stated vision is to confront pressing issues facing global aquatic habitats through pioneering science, conservation, and educational programming.The National Aquarium houses several exhibits including the Upland Tropical Rain Forest, a multiple-story Atlantic Coral Reef, an open ocean shark tank, and Australia: Wild Extremes, which won the "Best Exhibit" award from the Association of Zoos and Aquariums in 2008. The aquarium also has a 4D Immersion Theater. The aquarium opened a marine mammal pavilion on the adjacent south end of Pier 4 in 1990, and currently holds seven Atlantic bottlenose dolphins. Of the seven, six were born at the National Aquarium, one was born at another American aquarium.

Nature's Microworlds

Nature's Microworlds is a 2012 British nature documentary series. Produced by the BBC, the series is narrated by Steve Backshall and produced by Doug Mackay-Hope. There are thirteen thirty-minute episodes in the series, which was first broadcast on BBC Four. Each episode focuses on its eponymous region, exploring the wildlife of the microclimate found there: The featured ecosystems include the archipelago of volcanic islands known as the Galapagos, the grasslands of the Serengeti in Africa, the Amazon rainforest covering most of South America, the kelp forest located in California's Monterey Bay, the Okavango Delta where the Okavango River empties into a wetland surrounded by the Kalahari Desert, and the Arctic wilderness of the Svalbard archipelago.

Nature of America

Nature of America is a series of twelve self-adhesive stamp sheets that the United States Postal Service released annually between 1999 and 2010 starting with the Sonoran Desert sheet and ending with the Hawaiian Rain Forest Sheet. Like the Celebrate the Century stamp series, these were printed on large sheets 9"x8¾" (233mm x 171mm), but differed from the former in that they were self adhesive and not gummed.

Osaka Aquarium Kaiyukan

The Osaka Aquarium Kaiyukan (海遊館, Kaiyūkan, known as the Kaiyukan) is an aquarium located in the ward of Minato in Osaka, Japan, near Osaka Bay. It is one of the largest public aquariums in the world, and is a member of the Japanese Association of Zoos and Aquariums (JAZA).

The aquarium is about a five-minute walk from Osakako Station on the Osaka Municipal Subway Chūō Line, and is next to the Tempozan Ferris Wheel.

Pterygophora californica

Pterygophora californica is a large species of kelp, commonly known as stalked kelp. It is the only species in its genus Pterygophora (Ruprecht, 1852). It grows in shallow water on the Pacific coast of North America where it forms part of a biodiverse community in a "kelp forest".

Shifting baseline

A shifting baseline (also known as sliding baseline) is a type of change to how a system is measured, usually against previous reference points (baselines), which themselves may represent significant changes from an even earlier state of the system.

The concept arose in landscape architect Ian McHarg's 1969 manifesto Design With Nature in which the modern landscape is compared to that on which ancient people once lived. The concept was then considered by the fisheries scientist Daniel Pauly in his paper "Anecdotes and the shifting baseline syndrome of fisheries". Pauly developed the concept in reference to fisheries management where fisheries scientists sometimes fail to identify the correct "baseline" population size (e.g. how abundant a fish species population was before human exploitation) and thus work with a shifted baseline. He describes the way that radically depleted fisheries were evaluated by experts who used the state of the fishery at the start of their careers as the baseline, rather than the fishery in its untouched state. Areas that swarmed with a particular species hundreds of years ago, may have experienced long term decline, but it is the level of decades previously that is considered the appropriate reference point for current populations. In this way large declines in ecosystems or species over long periods of time were, and are, masked. There is a loss of perception of change that occurs when each generation redefines what is "natural".

Most modern fisheries stock assessments do not ignore historical fishing and account for it by either including the historical catch or use other techniques to reconstruct the depletion level of the population at the start of the period for which adequate data is available. Anecdotes about historical populations levels can be highly unreliable and result in severe mismanagement of the fishery.The concept was further refined and applied to the ecology of kelp forests by Paul Dayton and others from the Scripps Institution of Oceanography. They used a slightly different version of the term in their paper, "Sliding baselines, ghosts, and reduced expectations in kelp forest communities". Both terms refer to a shift over time in the expectation of what a healthy ecosystem baseline looks like.

Solromar, California

Solromar is a small unincorporated community in Ventura County, California, United States. Located at the north end of the Malibu coast, the community is just upcoast from Leo Carillo State Park. The community lies on a narrow coastal terrace along Pacific Coast Highway amidst some of the most striking and diverse coastal terrain in Ventura County.County Line Beach Park lies in-between portions of the residential areas on the ocean side of the highway. A popular surf spot mentioned by the Beach Boys in their 1963 hit song "Surfin' USA", the beach is also popular for scuba diving and freediving with easy access, abundant kelp forest, and reefs.

Solromar had a post office from 1944 to 1956. The post office selected the name from a list of twenty submissions by the residents. The Spanish words sol, oro, and mar were combined to suggest the description "golden sunset on the sea".This is the only residential community on the Malibu coast north of the Los Angeles County line. When Malibu incorporated as a city in Los Angeles County, this was the only community along the Malibu coast that was not included within the city limits. This portion of the south coast of Ventura County typically uses Malibu for the address as it is within a Malibu zip code. Sewer service in the area is provided by individual septic tank systems.California native garden and a monarch butterfly waystation were constructed as part of the MariSol subdivision. The U.S. Army Corps of Engineers has found a 0.9-foot per year (0.27 m) erosion rate for the shoreline with major erosion occurring during the winter months.

Splash and Bubbles

Splash and Bubbles is an American computer-animated children's television series created by John Tartaglia. The series debuted on PBS Kids on November 23, 2016, after Wild Kratts: Creatures of the Deep Sea. It is produced using motion capture that blends with animatronic interfaces which enables the crew to make animation.

Two Oceans Aquarium

The Two Oceans Aquarium is an aquarium located at the Victoria & Alfred Waterfront in Cape Town, Western Cape, South Africa. The aquarium was opened on the 13 November 1995 and comprises seven exhibition galleries with large viewing windows: The aquarium is named for its location, where the Indian and Atlantic Ocean meet.

Atlantic Ocean Gallery - This gallery allows you to discover the life of the Atlantic Ocean. Such marine life as translucent jellyfish, tiny and rare Knysna seahorse and giant spider crabs are kept here.

I&J Children's Play Centre - Various activities to keep the young visitors entertained. Puppet shows, arts and craft.

Previously known as the Seal Pool Exhibit. Cape fur seal are no longer kept at the aquarium. The last 4 resident seals were sent to another facility in 2007. Various fishes can be found in the pool and the rockhopper penguins also use this pool for their exercise.

Predator Exhibit - This exhibit re-opened on 27 July 2017. This exhibit holds 2 million litres of seawater. 3 ragged-tooth sharks were released on this day, named Lili-May, Dane and Bernie.It is possible to scuba dive in this tank.

I&J Ocean Exhibit - Opened on 16 June 2016. This exhibit holds 1.6 million litres of seawater. Various fishes, rays and turtles to be seen in this exhibit. It is possible to scuba dive in this tank at the aquarium if you hold a PADI Open Water Certificate.

Indian Ocean Gallery - Showcases six exhibits of marine life found in the Indian Ocean. The anemonefish (also known as clownfish) seen in the movie Finding Nemo and his friends and a wealth of other colourful fish can be found in this ocean’s coral reefs.

Kelp Forest Exhibit - (This exhibit reopened on 15 December 2018) / One of the aquarium’s biggest attractions, this underwater forest is home to shoals of silver fishes sparkling through the sunlight.

River Meander Exhibit - African Black-footed penguins, Northern Rockhopper penguins, African black oystercatcher, mole snake, Western Leopard toads, common platannas (African clawed frogs). A river course divided into 3 sections (upper, middle and lower) with freshwater fishes in the exhibit. Various plants from the Western Cape region.

Urchin barren

An urchin barren is an area of the subtidal where the population growth of sea urchins has gone unchecked, causing destructive grazing of kelp beds or kelp forests (specifically the giant brown bladder kelp, Macrocystis). The transition from kelp forest to barren is defined by phase shifts in which one stable community state is shifted to another. There is a theory that both sea urchin barrens and kelp-beds represent alternative stable states, meaning that an ecosystem can exist under multiple states, each with a set of unique biotic and abiotic conditions (i.e. barren except for urchins or flourishing with kelp). Those who argue for this theory propose several criteria: that different self-replacing communities dominate the site; each state exists longer than one complete turnover of the dominant community or species; and that following a disturbance (e.g. a storm), the system returns to the previous state.

Alternatively, another theory known as the continuous phase shift is widely accepted. This describes a transition from one ecosystem state to another where the threshold for the forward shift is at the same level as the threshold for the reverse shift back to the previous state. In other words, a kelp bed can re-establish itself when urchin grazing intensity decreases to the threshold density triggering the initial shift.

Over the past four decades, barrens have been reported along coastlines around the world, everywhere from Nova Scotia to Chile. They can either span over a thousand kilometers of coastline or occur in small patches.Sea urchins eat kelp holdfasts. This can be caused by a lack of sea otters or other predators in the area, which makes it extremely important to protect the ecological balance in a kelp forest. Keystone species such as the sea otter help maintain healthy kelp communities; however, because of overfishing and increased killer whale predation, their numbers are in decline. Off the California coast, storm runoff, erosion and polluted water allow less light to penetrate, weakening the kelp. Sea urchins then can move in and settle.

Despite their name, urchin barrens are usually abundant with marine invertebrate life, echinoderms in particular. Species such as the sunflower starfishes, brittle stars, and the purple sea urchin are common. Although macrofauna such as these are aplenty,

there is little primary productivity among microorganisms. This makes it difficult for newly settled sea urchins (juveniles) to survive, making barrens more dangerous for juveniles than for adults. Once having wiped out a kelp forest, the environment becomes unsupportive of new sea urchin settlement and adults are forced to find a new resource.

Aquatic ecosystems

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.