Quiz
Rocky reefs
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Questions in this quiz (21)
1Sections of rocky reef kelp ecosystem
Canopy
ØFronds lying on [blank_start]surface[blank_end] or midwater
ØMost [blank_start]light[blank_end]
Ø[blank_start]Most[blank_end] wave action
Understory
Ø[blank_start]Fronds[blank_end] erect or close to [blank_start]bottom[blank_end]
ØLess [blank_start]light[blank_end]
ØLess [blank_start]wave[blank_end] action
Ø[blank_start]Highest[blank_end] diversity of marine life in kelp forest
ØArea of [blank_start]stipes[blank_end]
Algal turf
Ø[blank_start]Short[blank_end] clumps, filaments and encrusting algae
Ø[blank_start]Least[blank_end] light
Ø[blank_start]Little[blank_end] to [blank_start]no[blank_end] wave influence
ØArea of [blank_start]holdfasts[blank_end] of larger kelp, [blank_start]invertebrates[blank_end], And [blank_start]red[blank_end] algae (especially abundant)
Algal community changes with water [blank_start]depth[blank_end]- Asurface
- Blight
- CMost
- DFronds
- Ebottom
- Flight.
- Gwave
- HHighest
- Istipes
- JLeast
- KLittle
- LShort
- Mno
- Nholdfasts
- Oinvertebrates
- Pred
- Qdepth
2What is a rocky reef?
• Hard [blank_start]substrate[blank_end] (rocks)
–various types (e.g. volcanic, sedimentary, etc.) –not [blank_start]living[blank_end] (e.g., not [blank_start]corals[blank_end] or [blank_start]bivalve[blank_end] shells)
• Usually along continental [blank_start]shelves[blank_end]
• Usually in [blank_start]temperate[blank_end] and [blank_start]subtropical[blank_end] areas (but also in [blank_start]tropical[blank_end] areas where corals can’t grow -- e.g., deep or [blank_start]murky[blank_end], or areas where there is high upwelling or where it is colder. eg found in the [blank_start]Galapogos[blank_end], despite it being a [blank_start]tropical[blank_end] area.
• Typically [blank_start]structurally[blank_end] complex (e.g., crevices to hide in)
• Often with [blank_start]algae[blank_end] attached to rocks...
a particular [blank_start]type[blank_end] of rocky reef with algae attached are [blank_start]kelp[blank_end] forests
kelp forests are v extensivein [blank_start]western[blank_end] coasts of [blank_start]s[blank_end] africa and [blank_start]w[blank_end] america- Asubstrate
- Bliving
- Ccorals
- Dbivalve
- Eshelves
- Fsubtropical
- Gtropical
- Htemperate
- Itropical.
- Jmurky
- KGalapogos
- Lstructurally
- Malgae
- Nkelp
- Otype
- Pwestern
- Qs
- Rw
3What is a kelp bed?
• Rocky reefs with [blank_start]macroalgae[blank_end]
–[blank_start]kelp[blank_end] [blank_start]forest[blank_end]: canopy forming kelps reach sea
surface (e.g., [blank_start]Macrocystis[blank_end])- giant [blank_start]pacific[blank_end] kelp, can grow v fast
–kelp [blank_start]bed[blank_end]: [blank_start]shorter[blank_end] kelps don’t reach surface
Kelp forests can refer to any type of [blank_start]brown[blank_end] [blank_start]seaweed[blank_end] that can form a [blank_start]canopy[blank_end]
• Highly [blank_start]productive[blank_end]- lots of carbon fixation
In terms of primary production, kelp forests are the temperate equivalent of [blank_start]coral reefs[blank_end] and the marine temperate version of [blank_start]tropical rain forests[blank_end]
• [blank_start]Additional[blank_end] structural [blank_start]complexity[blank_end] to the rocky reef, eg lots of [blank_start]juvenile[blank_end] fish living in the [blank_start]understory[blank_end]- Amacroalgae
- Bkelp
- Cforest
- DMacrocystis
- Epacific
- Fbed
- Gshorter
- Hbrown
- Iseaweed
- Jcanopy
- Kproductive
- Lcoral reefs
- Mtropical rain forests
- Ncomplexity
- OAdditional
- Pjuvenile
- Qunderstory
4Kelp forests can refer to any type of brown seaweed that can form a canopy
- ATrue
- BFalse
5True Kelp (Order Laminariales)
• [blank_start]Large[blank_end], [blank_start]brown[blank_end] [blank_start]sub[blank_end]tidal seaweeds
• Very [blank_start]strong[blank_end] holdfasts to stay attached
• Form [blank_start]dense[blank_end] forests on the [blank_start]west[blank_end] coast of [blank_start]North[blank_end] [blank_start]America[blank_end]
• “[blank_start]Brown[blank_end] algae” indicates the mix of photosynthetic pigments it has- ALarge
- BSmall
- Cbrown
- DRed
- EGreen
- FOrange
- Gsub
- HSupra
- ISuper
- Jstrong
- KWeak
- Ldense
- MSparse
- Nwest
- ONorth
- PNorth.
- QWest
- RAmerica
- SSouth
- TAfrica
- UBrown
- VRed.
- WGreen.
6Kelp is not a foundation species
- ATrue
- BFalse
7Kelp is a [blank_start]foundation[blank_end] species
Definition: A species that has a [blank_start]strong[blank_end] role in [blank_start]structuring[blank_end] the ecological community. without it you have a really [blank_start]different[blank_end] ecological community
Ø Can be in [blank_start]any[blank_end] trophic level...primary producers, secondary consumers,
predators...
Ø Sometimes used interchangeably with “[blank_start]keystone[blank_end] species”
[blank_start]sea[blank_end] stars are a [blank_start]keystone[blank_end] species in the [blank_start]intertidal[blank_end] environments, [blank_start]corals[blank_end] are, big dominant [blank_start]predators[blank_end], eg wolves, grizzly in Yellowstone and polar bears,
getting rid of them [blank_start]may[blank_end] lead to a [blank_start]phase[blank_end] shift from one [blank_start]community[blank_end] to another- Afoundation
- Bprimary
- Cstrong
- Dweak
- Eintermediate
- Fstructuring
- Gcontrolling
- Hdeveloping
- Imaintaining
- Jdifferent
- Ksimilar
- Lany
- Mone
- Nkeystone
- Oprimary
- Papex
- Qintertidal
- Rsubtidal
- Scoastal
- Tphase
- Uslow
- Vtimely
- Wecological
- Xcommunity
- Yecosystem
- Zpopulation
- AAmay
- ABmay not
- ACsea
- ADthrowing
- AEkeystone
- AFfoundation
- AGcorals
- AHweeds
- AIrocks
- AJpredators
- AKconsumers
- ALcarnivores
8General kelp and seaweed structure
• Seaweeds [blank_start]do[blank_end] lack ‘true’ leaves, stems, or [blank_start]roots[blank_end]
• Flat [blank_start]blades[blank_end] [blank_start]instead[blank_end] of leaves
- [blank_start]high[blank_end] surface area to volume ratio
– Chlorophyll [blank_start]is[blank_end] concentrated here
– [blank_start]High[blank_end] SA/V to maximize [blank_start]nutrient[blank_end] absorption
• [blank_start]Air[blank_end] filled pneumatocysts allow blades to [blank_start]float close to the surface[blank_end]
– Grape to volleyball sized
– Blades closer to light
• [blank_start]Stipe[blank_end] - strong, [blank_start]flexible[blank_end] link between blades and holdfast
– provides Shock absorption
– [blank_start]is[blank_end] Photosynthetic
• Holdfasts
- [blank_start]are[blank_end] root-like structures
- [blank_start]do[blank_end] keep seaweeds anchored to the [blank_start]bottom[blank_end]
– [blank_start]Unlike[blank_end] true roots, holdfasts [blank_start]don’t[blank_end] absorb nutrients- Ado
- Bdon't
- Croots
- Dflowers
- Eblades
- Fpaddles
- Gstructures
- Hinstead
- Ias well as
- Jhigh
- Klow
- Lis
- Mis very un-
- NHigh
- OLow
- PAverage
- Qnutrient
- ROxygen
- SLight
- TAir
- UWater
- VCO2
- WHydrogen
- XOxygen
- Yfloat close to the surface
- Zbe neutrally buoyant
- AAsink
- ABmaintain their horizontal structure
- ACStipe
- ADStripe
- AEStalk
- AFBlade
- AGPhloem
- AHflexible
- AIridgid
- AJis
- AKis not
- ALare
- AMare not
- ANdo
- AOdont't
- APbottom
- AQrock
- ARalgal turf
- ASUnlike
- ATLike
- AUdon’t
- AVdo
9note- for the half covered one dont include the cyst in the answer
- ABlades
- BHoldfast
- CStipe
- DThallus
10Canopy kelps extend 5-[blank_start]4[blank_end]5 m above the substrate,
[blank_start]stipitate[blank_end] kelps usually extends less than 2 m above the substrat, [blank_start]prostrate[blank_end] kelps often drape the seafloor.
[blank_start]Phylogenetically[blank_end] not close but due to [blank_start]convergent[blank_end] evolution they form the same morphology.- A4
- Bstipitate
- Cprostrate
- DPhylogenetically
- Econvergent
11Life in kelp understory
• Kelp stipes -- tube-forming p[blank_start]olychaetes[blank_end], bry[blank_start]ozoans[blank_end], other [blank_start]sessile[blank_end] organisms
• Surf perches ([blank_start]eat[blank_end] small crustaceans)
• Topsmelt and Blue rockfish (pl[blank_start]ankton[blank_end] feeders)
• Larvae of [blank_start]benthos[blank_end]
- Aolychaetes
- Bozoans
- Csessile
- Deat
- Eankton
- Fbenthic organisms
12 Steller's sea cow (Hydrodamalis gigas)
• Order Sirenia: includes manatees and dugongs
• Up to 10 meters long (~5-10 tonnes), other Sirenians
are much smaller (~4-5 metres in length)
• Grazed almost exclusively on [blank_start]kelp[blank_end] in the [blank_start]canopy[blank_end]
Ø It had no [blank_start]teeth[blank_end], just broad bony pads to chew kelp
lived in kelp [blank_start]forests[blank_end] where [blank_start]predators[blank_end] eg sharks couldn’t go
couldn’t dive down bc so much blubber they were too [blank_start]buoyant[blank_end]
• Range: northern [blank_start]Pacific[blank_end] ocean (Be[blank_start]ring[blank_end] sea)
• During the Pl[blank_start]eisto[blank_end]cene (last [blank_start]inter[blank_end]glacial) it ranged
much further south
• [blank_start]Hunted[blank_end] to extinction ~ 250 years ago, just 30 years
after it was discovered
Ø Each p[blank_start]opulation[blank_end] only produced few offspring per
year, [blank_start]long[blank_end] generation times, and [blank_start]low[blank_end] population growth, making it highly susceptible to extinction.- Akelp
- Bcanopy
- Cteeth
- Dpredators
- Eforests
- Fbuoyant
- GPacific
- Hring
- Iinter
- Jeisto
- KHunted
- Llong
- Mlow
- Nopulation
13Organisms associated with algal turf
• Kelp holdfast -- small invertebrates, b[blank_start]rittle[blank_end] stars, p[blank_start]olychaetes[blank_end], sea u[blank_start]rchins[blank_end], cr[blank_start]abs[blank_end]
• Many species of ad[blank_start]ult[blank_end] rockfishes and kelp bass (herbi[blank_start]vor[blank_end]es)
• She[blank_start]eph[blank_end]ead (eats cr[blank_start]a[blank_end]bs, ur[blank_start]chi[blank_end]ns)
• Abalone (eat l[blank_start]ive[blank_end] kelp, dr[blank_start]ift[blank_end] kelp, and [blank_start]algal[blank_end] turf)- Arittle
- Brchins
- Cabs
- Dolychaetes
- Eult
- Fvor
- Geph
- Ha
- Ichi
- Jive
- Kift
- Lalgal
14 Global distribution of kelp forests
Not found in the [blank_start]tropics[blank_end] because they are too [blank_start]hot[blank_end] and [blank_start]nutrient[blank_end] poor
Not found in [blank_start]Polar[blank_end] systems due to [blank_start]ice[blank_end] scour and l[blank_start]ight[blank_end] limitation
Only found in [blank_start]temperate[blank_end] regions
n temperate regions go from A[blank_start]laska[blank_end] down to B[blank_start]aj[blank_end]a C[blank_start]alifornia[blank_end]
then from starts again in northern P[blank_start]eru[blank_end].
Also found in s A[blank_start]frica[blank_end], A[blank_start]ustrali[blank_end]a, J[blank_start]apan[blank_end], Ch[blank_start]ina[blank_end], up to No[blank_start]rway[blank_end].
What controls the distribution of kelp beds?
• Substrate: require h[blank_start]ard[blank_end] substrates to attach
• [blank_start]Light[blank_end]: They need l[blank_start]ight[blank_end] to p[blank_start]hotosynthesise[blank_end] (so close to the [blank_start]surface[blank_end])
• Nutrients: They need lots of [blank_start]dissolved[blank_end] [blank_start]inor[blank_end]ganic nutrients to support [blank_start]photosynthesis[blank_end]
• This is why kelp beds are limited to the temperate zones, but their distribution can be extended in [blank_start]up[blank_end]welling zones!- Atropics
- Bhot
- Cnutrient
- DPolar
- Eice
- Fight
- Gtemperate
- Hlaska
- Iaj
- Jalifornia
- Keru
- Lfrica
- Mustrali
- Napan
- Oina
- Prway
- Qard
- Rsurface
- SLight
- Tight
- Uhotosynthesise
- Vdissolved
- Winor
- Xphotosynthesis
- Yup
15What causes kelp deforestation?
Remember, Upwellings are s[blank_start]easonal[blank_end], but they also vary among years (e.g. [blank_start]El-Nino[blank_end] events)
Anomalies of physical conditions that push the physiological tolerance of kelps– e.g.
El-[blank_start]Nino[blank_end] events, temperature or s[blank_start]alinity[blank_end] anomalies
El- Niño causes [blank_start]reversal[blank_end] of normal weather patterns, the events are cyc[blank_start]lical[blank_end].
normally off the coast of p[blank_start]eru[blank_end] there is much upwelling of [blank_start]cold[blank_end], nutrient [blank_start]rich[blank_end] water, El Niño brings an intrusion of [blank_start]warm[blank_end] water from the [blank_start]west[blank_end], increasing sea [blank_start]surface[blank_end] temperatures and [blank_start]decreasing[blank_end] nut[blank_start]rient[blank_end] levels.
La [blank_start]Niña[blank_end] reduces temperatures and kelp cover [blank_start]increases[blank_end] during these years.
• Storms (removes k[blank_start]elp[blank_end] and/or sea urchins)
• Sea urchins getting out of control (due to p[blank_start]redators[blank_end], food l[blank_start]imitation[blank_end], etc) (urchins eat d[blank_start]rift[blank_end] kelp, if no d[blank_start]rift[blank_end] kelp they [blank_start]eat[blank_end] the holdfasts)
Sea urchins are h[blank_start]erbivores[blank_end] and potentially destructive to kelp
• Urchins normally pa[blank_start]ssively[blank_end] feed on drift kelp (free-floating k[blank_start]elp[blank_end] detritus)
• When d[blank_start]rift[blank_end] kelp is l[blank_start]imited[blank_end], and urchins start to experience f[blank_start]ood[blank_end] limitation, and their feeding b[blank_start]ehavior[blank_end] changes
Aggregate into a feeding “[blank_start]front[blank_end]”
• Start to feed on l[blank_start]ive[blank_end] kelp holdfasts, rather than d[blank_start]rift[blank_end] kelp.
• Dislodge them from the bed f[blank_start]loor[blank_end]
This can create an urchin [blank_start]barren[blank_end], where Kelp forest has been deforested by urchin grazing. Cru[blank_start]sto[blank_end]se cor[blank_start]alli[blank_end]ne algae replaces all other sea[blank_start]weed[blank_end]s.
In a Kelp forest with low densities of [blank_start]urchins[blank_end]. Mix of kelp and other types of tu[blank_start]rf[blank_end] algae.
Urchin barrens are [blank_start]widespread[blank_end], and can vary in du[blank_start]ration[blank_end]- Aeasonal
- BEl-Nino
- CNino
- Dalinity
- Ereversal
- Flical
- Geru
- Hcold
- Irich
- Jwarm
- Kwest
- Lsurface
- Mdecreasing
- Nrient
- ONiña
- Pincreases
- Qelp
- Rredators
- Simitation
- Trift
- Urift
- Veat
- Werbivores
- Xssively
- Yelp
- Zrift
- AAimited
- ABood
- ACehavior
- ADfront
- AEive
- AFrift
- AGloor
- AHbarren
- AIalli
- AJsto
- AKweed
- ALurchins
- AMrf
- ANwidespread
- AOration
16When urchins get out of control, they initiate a “[blank_start]phase[blank_end] shift” in kelp b[blank_start]ed[blank_end] ecosystems
ØDefinition: When an e[blank_start]cosystem[blank_end] changes from one s[blank_start]table[blank_end] state to another due to per[blank_start]turbation[blank_end]s. In this case, the ecosystem changes from a kelp [blank_start]forest[blank_end] to an urchin [blank_start]barren[blank_end].
• These shifts are [blank_start]widely[blank_end] distributed, are sometimes but not always r[blank_start]eversible[blank_end], and can vary in d[blank_start]uration[blank_end].
General kelp health
• Healthy abundant kelps provide abundant d[blank_start]etritus[blank_end] for urchins, keep them in check
• The wh[blank_start]iplash[blank_end] motion of the kelp will also deter u[blank_start]rchins[blank_end] from entering the kelp [blank_start]forest[blank_end], and will prevent them from at[blank_start]taching[blank_end] to the kelp
• Therefore, any physiological or environmental source of stress for the kelp can pr[blank_start]omote[blank_end] urchins- Aphase
- Bed
- Ctable
- Dcosystem
- Eturbation
- Fforest
- Gbarren
- Hwidely
- Ieversible
- Juration
- Ketritus
- Liplash
- Mrchins
- Nforest
- Otaching
- Pomote
17The sea otter-driven trophic cascade
A [blank_start]chain[blank_end]-reaction within [blank_start]food[blank_end] webs that results from changing p[blank_start]opulation[blank_end] d[blank_start]ensities[blank_end] at higher [blank_start]trophic[blank_end] levels, shifting the d[blank_start]ominance[blank_end] and im[blank_start]pact[blank_end] of co[blank_start]nsumers[blank_end] in lower levels.
Trophic Ecology
Bottom-up vs. Top-down control of c[blank_start]ommunity[blank_end] structure
Bottom up = [blank_start]productivity[blank_end] driven
Top-down = Trophic [blank_start]cascades[blank_end]
predator -> h[blank_start]erbivore[blank_end] -> primary [blank_start]producer[blank_end] (s[blank_start]econd[blank_end] level organism (herbivore) releases the lowest level to proliferate)
e.g., Fish -> [blank_start]Zoo[blank_end]plankton -> [blank_start]Phyto[blank_end]plankton
Effects of trophic cascades are stronger in [blank_start]simple[blank_end] systems (marine) than in [blank_start]complex[blank_end] systems (terrestrial)
Inter[blank_start]annual[blank_end] variability in top [blank_start]predators[blank_end] can induce [blank_start]inter[blank_end]annual differences in otters, urchins and kelps
eg in the Aleutians, [blank_start]Alaska[blank_end], there is a [blank_start]simple[blank_end] food web with intermediate diversity,
Whales eat m[blank_start]ore[blank_end] otters possibly because their other food sources (e.g. [blank_start]seals[blank_end]) are declining
The trophic cascade may also affect coastal [blank_start]bioeros[blank_end]ion rates...- Achain
- Bfood
- Copulation
- Densities
- Etrophic
- Fominance
- Gpact
- Hnsumers
- Iommunity
- Jproductivity
- Kcascades
- Lerbivore
- Mproducer
- Necond
- OZoo
- PPhyto
- Qsimple
- Rcomplex
- Sannual
- Tpredators
- Uinter
- VAlaska
- Wsimple
- Xseals
- Yore
- Zbioeros
18In W[blank_start]estern[blank_end] N[blank_start]orth[blank_end] A[blank_start]tlantic[blank_end], there is a Simple food webs, with very strong interactions.
The p[blank_start]rostrate[blank_end] Laminar kelp, sea urchins and the Atlantic cod. the c[blank_start]oastal[blank_end] cod was hunted to e[blank_start]xtinction[blank_end]. The cod are functionally similar to the sea [blank_start]otters[blank_end].
A bit further North at N[blank_start]ova[blank_end] S[blank_start]cotia[blank_end], there was similar dynamics to Maine in terms of p[blank_start]redator[blank_end] collapse (case of the cod), but there urchin [blank_start]diseas[blank_end]e is also important. [blank_start]disease[blank_end]s can have a v quick effect bc in high population d[blank_start]ensities[blank_end] it spreads f[blank_start]aster[blank_end] therefore v short [blank_start]la[blank_end]g.
Recovery of kelp after [blank_start]urchin[blank_end] disease episode encouraged c[blank_start]rabs[blank_end] to migrate into kelp beds.
These feed on urchin [blank_start]larva[blank_end]e, preventing urchin [blank_start]recruit[blank_end]ment!
Therefore, although we’ve seen many more urchins settle since the return of kelp, almost none of them survive due to crab p[blank_start]redation[blank_end]!
They also feed on diseased a[blank_start]dult[blank_end] urchins.- Aestern
- Borth
- Ctlantic
- Drostrate
- Extinction
- Foastal
- Gotters
- Hova
- Icotia
- Jredator
- Kdiseas
- Ldisease
- Mensities
- Naster
- Ola
- Purchin
- Qrabs
- Rlarva
- Srecruit
- Tredation
- Udult
19IN [blank_start]southern[blank_end] California, [blank_start]High[blank_end] in diversity. [blank_start]Rarely[blank_end] shift to barrens, [blank_start]Otters[blank_end]wereremovedfromC[blank_start]alifornia[blank_end]manyyearsago (between 150-200 years), yet phase shifts were only apparent recently, Manydiversec[blank_start]onsumers[blank_end]includingpredatorsand herbivores that could have f[blank_start]unctional[blank_end]ly replaced ot[blank_start]ters[blank_end] or [blank_start]urchins[blank_end], thereby b[blank_start]ufferin[blank_end]g the ec[blank_start]osystem[blank_end] from change.
• However,we’vesystematicallyremovedmanyofthese commercially valuable consumers such as ab[blank_start]alone[blank_end], s[blank_start]heephea[blank_end]d, [blank_start]spiny[blank_end] lobster etc.
We’re now seeing more [blank_start]urchin[blank_end] barrens in California!
so the main reasons for increasing urchin barrens are:
- [blank_start]El[blank_end]-[blank_start]Niño[blank_end] events (more [blank_start]EL[blank_end] [blank_start]NIño[blank_end]= v important)
- More st[blank_start]orms[blank_end]
- Weak or no [blank_start]upwell[blank_end]ing
- Warmer
- [blank_start]Less[blank_end] nutrients delivered to the coast
- R[blank_start]emoval[blank_end] of large predators
- Release [blank_start]herbivo[blank_end]res from pr[blank_start]edatio[blank_end]n- AHigh
- BRarely
- Csouthern
- DOtters
- Ealifornia
- Fonsumers
- Gunctional
- Hters
- Iurchins
- Jufferin
- Kosystem
- Lalone
- Mheephea
- Nspiny
- Ourchin
- PNiño
- QEl
- REL
- SNIño
- Torms
- Uupwell
- VLess
- Wemoval
- Xherbivo
- Yedatio
20 Continuous vs. discontinuous phase shifts
Continuous (l[blank_start]inea[blank_end]r): path [blank_start]backward[blank_end] is the same as path forward.
F1 and F2 are called [blank_start]tippin[blank_end]g points
D[blank_start]iscontinuous[blank_end] ([blank_start]non[blank_end]-li[blank_start]near[blank_end]): path backward is [blank_start]not[blank_end] the same as path forward.
Discontinuous phase shifts are [blank_start]harder[blank_end] to predict, and [blank_start]harder[blank_end] to reverse[blank_start]![blank_end]
usually happens when theres [blank_start]higher[blank_end] di[blank_start]versity[blank_end]
When do phase shifts reverse?
• Athresholdisthe[blank_start]change[blank_end]inthesystemthatleads to a s[blank_start]hift[blank_end] from one [blank_start]phas[blank_end]e to the other
• Urchin [blank_start]densit[blank_end]y is clearly a threshold for the creation of urchin barren phase
• Is the threshold for reversing it equivalent in magnitude?
– Is reducing urchin density back to its former level enough to switch the system back?
– Not always!
depends upon the [blank_start]ecostem[blank_end] and r[blank_start]egio[blank_end]n in question
Threshold for creating the barren are different than for reversing the barren, bc Feedback processes [blank_start]stabilize[blank_end] phases
Healthy kelps create a lot of processes which l[blank_start]imit[blank_end] urchins;
eg [blank_start]whipla[blank_end]sh decreases urchin grazing,
more kelp= more sp[blank_start]ore[blank_end] production, so more kelp
more kelp= more [blank_start]detrit[blank_end]us so less urchin mi[blank_start]gratio[blank_end]n and less urchin gra[blank_start]zing[blank_end], both of which lead to more kelp, more kelp = greater pr[blank_start]edator[blank_end] abundance, eg more sh[blank_start]epherd[blank_end]s and spiny [blank_start]lobsters[blank_end]
These create [blank_start]positive[blank_end] feedbacks for the [blank_start]kelp[blank_end] bed, and [blank_start]negative[blank_end] feedbacks for the urchin bed
Urchins in barrens create conditions to p[blank_start]romote[blank_end] local urchin re[blank_start]productive[blank_end] success and rec[blank_start]ruitment[blank_end], but that prevent kelp from settling and thriving
eg barren state means less [blank_start]detri[blank_end]tus so [blank_start]greater[blank_end] urchin migration and [blank_start]greater[blank_end] destructive grazing, both of which enhance the [blank_start]barren[blank_end] state.
barren state means lower predator abundance so enforces barren state
Barren state facilitates urchin se[blank_start]ttlem[blank_end]ent and [blank_start]increases[blank_end] urchin fert[blank_start]ilisation[blank_end] rate, both of which increase urchin rec[blank_start]ruitment[blank_end], which facilitates the barren state.
Des[blank_start]tructive[blank_end] gr[blank_start]azing[blank_end] decreases kelp rec[blank_start]ruitment[blank_end] which [blank_start]increases[blank_end] barren state.
very [blank_start]hard[blank_end] to predict- very r[blank_start]egio[blank_end]n and ti[blank_start]min[blank_end]g specific- Ainea
- Bbackward
- Ctippin
- Discontinuous
- Enon
- Fnear
- Gnot
- Hharder
- Iharder
- J!
- Khigher
- Lversity
- Mchange
- Nhift
- Ophas
- Pdensit
- Qecosystem
- Regio
- Sstabilize
- Timit
- Uwhipla
- Vore
- Wdetrit
- Xgratio
- Yzing
- Zedator
- AAeephead
- ABlobsters
- ACkelp
- ADpositive
- AEnegative
- AFromote
- AGproductive
- AHruitment
- AIdetri
- AJgreater
- AKgreater
- ALbarren
- AMttlem
- ANincreases
- AOilisation
- APruitment
- AQazing
- ARtructive
- ASruitment
- ATincreases
- AUhard
- AVmin
- AWegio
21Another species that sea otters prey upon is the Black [blank_start]abalone[blank_end], Haliotis cracherodii, which is also a [blank_start]graz[blank_end]er.
Eats [blank_start]drift[blank_end] kelp
lives down on the algal turf eats kelp as it drifts into shore
• Lives in the l[blank_start]ow[blank_end] [blank_start]inter[blank_end]tidal – s[blank_start]hallow[blank_end] [blank_start]sub[blank_end]tidal,
• Br[blank_start]oadca[blank_end]st spawns ~once a [blank_start]year[blank_end]
• Juveniles reside in rock crevices to hide from
predators (sea-[blank_start]otters[blank_end], sheep[blank_start]head[blank_end])
• Competition for space with sea-[blank_start]urchins[blank_end]
• Can live >30 [blank_start]years[blank_end]
• Harvested by humans >10,000 years
• Withering foot [blank_start]syndrome[blank_end]
• Endangered (as are [blank_start]sea[blank_end]-otters)
Withering syndrome (WS) is a [blank_start]bacteri[blank_end]al infection that has become highly prevalent in populations inhabiting the warmer waters of California, causing local extinctions of this species.
Ø WS discovered in 1985
Ø It is less prevalent in the cooler waters of Central/n[blank_start]orthern[blank_end] California (more [blank_start]up[blank_end]welling)
Ø Infection rate thought to be largely mediated by water [blank_start]temperature[blank_end] ([blank_start]El[blank_end] Niño and climate change)
At sites where abalone are not yet infected with WS, their abundances are [blank_start]negatively[blank_end] affected by predation from sea-otters.
Abalone [blank_start]density[blank_end] is actually higher in areas with high [blank_start]otter[blank_end] density Why?
• High otter density also means [blank_start]lower[blank_end] [blank_start]urchi[blank_end]n density, increasing the
availability of abalone food (k[blank_start]elp[blank_end]!)
• Juvenile abalone appear to make [blank_start]greater[blank_end] use of rock crevices where
otter densities are high.
high re[blank_start]fuge[blank_end] value- so juveniles not eaten by otters as much S
• [blank_start]Positive[blank_end] relationship between abalone density and habitat with high [blank_start]refuge[blank_end] value
• [blank_start]Positive[blank_end] relationship between abalone density and otter [blank_start]density[blank_end]- Aabalone
- Bgraz
- Cdrift
- Dow
- Einter
- Fhallow
- Gsub
- Hoadca
- Iyear
- Jotters
- Khead
- Lurchins
- Myears
- Nsyndrome
- Osea
- Pbacteri
- Qorthern
- Rup
- Stemperature
- TEl
- Unegatively
- Vdensity
- Wotter
- Xlower
- Yurchi
- Zelp
- AAgreater
- ABfuge
- ACPositive
- ADrefuge
- AEPositive
- AFdensity
Information
- Description
- degree marine ecology Quiz on Rocky reefs, created by Genie V on 11/04/2018.
- Author
- Genie V
- Language
- English
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