Midterm 3 Flashcards

Question

Fish schools and nutrients hotspots

Answer 1

High fish biomass sites= 10x more N and P nutrient hotspots attract herbivorous fishes -increases in herbivory prevents strong increase in macroalgae at hotspots (higher average bites per minute) -results in an increase in coral growth (75%) at hotspots

Answer 2

corals with aggregations of resident grunts -30% more tissue mass -25% more tissue N -29% more zoozanthellae -70% **higher growth rate**

Answer 3

-seabirds aggregate in very high densities -catch food in open ocean and move nutrients and terrestrial sediments to reefs

Answer 4

-Native (N) vs Palm (P) forests -abundance of birds was higher with native forests than palm -native forests had higher N, zooplankton, more nutrients -more manta rays in native forests due to increasing zooplankton

Answer 5

High rats=low seabirds -less nutrients are imported to the reef because of the decrease in seabirds Island without rats -damselfish grow faster (more nutrients) -more herbivorous fish -higher bio erosion and herbivory -different algal communities (CCA)

Answer 6

Successful restoration program that eradicated rats on the Tetiaroa Atoll

Answer 7

-**Vectors**:Organism introduced to new habitat (intentional introductions, boat propellers, underbelly of ships) -**frequent invasion**: repeated introductions/vectoring events -**ecological compatibility**: survive abiotic template and exploit resources-> good invaders, likely generalists, withstand lots of habitats and stresses -**survival of initial population bottleneck**: small population, low genetic diversity -> need rapid local population increases, disturbance many allow low level invader to take over

Answer 8

1. **introduction**:organism has to overcome a major geographic barrier (via human interactions). However, these fail to maintain populations over long periods of time 2. **naturalization**:local environment (biotic and abiotic) and reproductive barriers are overcome and regular reproduction occurs 3. **invasion**: overcome dispersal barriers

Answer 9

-deeper sections (below 30-40m) -down to 150m -upper vs lower mesophotic - transition -still has photosynthetic organisms -buffered from major bleaching and storm events, lower disturbance rates -community similarity btwn shallow and deep decreases with depth -very bottom of light range -larger eyes, organisms are more red

Answer 10

-low light and wave exposure- minimal temp gradient -relatively high nutrients -corals tend to have ‘plate’ morphologies to gather light/limited wave exposure

Answer 11

-fewer herbivores (low primary production),high planktivores -distinct fish assemblages upper vs lower -upper:spp that exist in shallow and deep water -lower dominated by 2 mesophotic specialists (filterfeeding) - 30-40m: turf algae, fleshy macro algae and corals -40-90m: bryozoans, black corals and sponges -endemism: only exists in specific location

Answer 12

MCE: mesophotic coral ecosystem -species that are limited to a specific area -higher endemism in mesophotic reefs, compared to shallow reefs -increases with latitude

Answer 13

Mostly in situ -remotely operated vehicles (ROVs) -rebreather diving -ARMS: autonomous reef monitoring structure Deeper reefs host significantly different brachyuran communities, and have a much lower total abundance -4-27 unique morphospecies per depth -3 out of 69 morphospecies across entire depth range

Answer 14

-increased heterotrophy, more energy from eating zooplank -reduced energy requirements -still have photosynthetic symbionts, which are morphologically different from shallow coral symbionts-> more efficient at photosynthesis -leptoseris: lower photosynthetic pigment concentration -chlorophyll b isn’t produced by symbionts->strong relationship with endolithic algae (low light adaptation) -superior light harvesting comes from skeletal morphology, not pigment concentration-> lets in light and allows it to bounce around the coralite (reflects light) and maximizing photosynthesis

Answer 15

-manta rays travel between shallow and mesophotic reefs and moves nutrients back and forth -upper 10m during the day -deeper water throughout the night to feed -role as an ecological link btwn epipelagic and mesopelagic habitats

Answer 16

-possible serves as refuges for corals to recover after disturbance -unexpectedly large areal extent of mesophotic reefs -it is important to understand the connectivity across the depth gradient

Answer 17

-deep reefs proposed as refuges against major disturbances affecting shallow reefs -they provide coral propagules to aid in shallow reef recovery -primarily upper mesophotic depths (30-60m) -> deep enough to escape disturbances but shallow enough to have overlap in species

Answer 18

Brooding species (Agaricia fragilis): depth-associated genetic differences in the brooding spp (different populations) -connectivity over ecological time scale is limited -didn’t exchange genetic material Broadcasting spp (Stephanocoenia intersepta): no genetic structuring btwn depths (same populations) -substantial potential for vertical connectivity -did exchange genetic material Reseeding potential of deep reefs may apply to only a small number of spp (<25% of corals)

Answer 19

>60m lack of live coral habitat >70m majority of fisheries spp found from shallow Mesophotic reefs fish>MPAs Mesophotic depths essential fish habitat and refuge

Answer 20

-water clarity is key for photosynthesis and coral health -high levels of sedimentation=low water clarity and low photosynthesis

Answer 21

Mucus entanglement, ciliary action, tentacular manipulation -comes at an energetic cost->less energy for coral maintenance -increase energy to shed sediments->mucus production -sedimentation can directly kill corals -sediments create spaces of mortality where they settle on the coral

Answer 22

-suppresses coral recruitment and replenishment of coral larvae

Answer 23

-sediments bound in algal turfs suppresses herbivory -positive feedback on algal growth -negative feedback on corals Increase sediment=suppression of herbivory = increase algal growth

Answer 24

-oxybenzone on coral larval survival -at high concentrations oxybenzone does affect the morphology of coral larvae and it begins to calcify -at very high concentrations the larvae die -increases bleaching, decreases PS -increases DNA damage in larvae ->genotoxicant -causes larval deformation-skeletal endocrine disrupter -the concentrations tested were similar to concentrations seen in the ocean

Answer 25

-zinc oxide has been found to be more harmful to coral photo systems than chemical sunscreens -zinc oxide causes coral bleaching ->symbiosis breakdown -unsure if the concentrations of zinc tested matches the concentrations seen in the ocean -titanium oxide = minimal impact to corals

Answer 26

-corals usually do well in waters where inorganic nutrient concentrations are low -more ammonium (NH4) = faster coral growth -ammonium vs nitrate -corals don’t have the mechanisms to use nitrate, they can’t regulate it->symbiont is less reliant on coral -amount of chlorophyll in cells is increased by ammonium in zoozanthellae->significantly more with ammonium->makes symbionts more effective -ammonium coals send more C back to corals

Answer 27

-nitrate exacerbated bleaching prevalence and duration in Acropora -nitrate tripled coral mortality in Pocillopora (symbionts are more selfish, less willing to give corals carbon -no effect of urea -nitrate=human-derived -urea=fish derived

Answer 28

Nutrients increase disease severity -increase in tissue loss-> more susceptible to disease and heat stress -disease progresses faster when nutrients are added

Answer 29

-partially enclosed Bay -few inhabitants until 1930s -high biodiversity and large % of coral color -Kaneohe Marine Corps Air station released sewage into the bay (5 million a day) -nitrate major N type in sewage Results: large decline in coral cover and large macroalgae bloom -phase shift from coral dominated to algal dominated -the area recovered once sewage outflow stopped -sewage also caused disease in fishes

Answer 30

-23 nuclear tests -water to 55,000 degrees C -shock waves to 70m deep -completely decimated the area of corals Present Day: ~150 spp -if we leave reefs alone, generally they can recover

Answer 31

-one of the most pressing issues in reef deterioration and coral mortality -fast emergence, high virulence, widespread distribution -30% of corals worldwide lost to disease during the last 30yrs

Answer 32

Caribbean Combination of: -density of human population -temp -coral diversity is lower in the Caribbean -low herbivore biomass and richness -high rates of algal growth

Answer 33

-responsible for the significant reduction in coral cover -70s: coral cover was 40-60% -2002: <10% coral cover

Answer 34

-1980s: white band disease killed majority of Acropora in Caribbean -up to 98% of Acropora in Caribbean disappeared -resulted in a transition from Acropora to Agaricia -1980s and before: Acropora was dominant -1990s to present: Agaricia was dominant

Answer 35

-‘new’ disease as of 2015 -started in Florida and spread throughout the Caribbean -agent is unknown, but likely bacteria->responds to antibiotics -rapid spread -rapid coral mortality -affects up to 25 coral spp -high prevalence: up to 100% of colonies of some spp, typical disease prevalence in 5-10%, kills in weeks to months

Answer 36

-rare and patchy nature of the incidence of disease -difficulty of in situ distinction btwn disease tissue loss and other mortality, and distinguishing btwn other diseases

Answer 37

-difficulty culturing potential pathogens from marine environment -difficulty isolating pathogens and reinfecting to show causative agent -difficulty in providing genetically uniform experimental animals for infection and transmission studies -complexity of coral holobiont -deficient understanding of coral defenses

Answer 38

-1st reported coral disease -worldwide distribution now reported (1st Caribbean, now in Indo-Pacific) -<2% of population affected -significant relationship with H2O temp and nutrients -> more pathogenic -causative agent: beggiatoa -Cyanobacteria, gliding bacterium with sulfur incisions, sulfate-reducing bacteria, other bacteria, fungi

Answer 39

-fungal disease that has been affecting gorgonians since 1980s -causative agent: Aspergillosis sydowii -spores germinate on coral surface and hyphae penetrate and spread in coral tissue -once infected coral tissue can’t be used to filter feed, tissue becomes hardened -primary and secondary infections -coral response: gall that encapsulates fungus -A. Sydowii may not be the only pathogen Where did it come from:movement of dust storms from Sahara desert, moving terrestrial organisms or Orinoco river plume (sediments with fungi get trapped in corals)

Answer 40

-aka patchy necrosis -causative agent: Serratia marcescens (common fecal enterobacterium)->associated with waterborne infection in tropical waters and hospital-spread infections -often present in sewage -Corallophila abbreviata: a corallivorous snail that is a reservoir and vector of S. marcescens->holds bacteria in mouth and passes it from coral to coral

Answer 41

-Florida’s mystery coral-killer identified -bacterial disease -genus of causative agent: Sphyngomonas -Denner IDed new genus and species as Auratimonas coralicida

Answer 42

-40 diseases reported worldwide -only 9 with identified pathogens

Answer 43

-bleaching -nutrients -plastics -tourism/breakage -fishing

Answer 44

-high temps and bleaching can leave corals more vulnerable to disease -can quickly kill part or all of the coral colony -lag effect (bleaching 1st, disease 2nd)

Answer 45

It increases severity by increasing the stress of the corals -corals with yellow and and aspergillosis experienced more tissue loss with added nutrients

Answer 46

Plastics increase coral disease <10% disease prevalence for corals without plastic ~100% disease prevalence for corals in contact with plastic -massive and branching corals are most affected by -vectoring new microbes into corals -physical interaction of plastic with corals

Answer 47

Increased interaction with tourists=increased coral breakage -more susceptible to coral disease by increasing their stress

Answer 48

MPAs vs fished area -more disease in regularly fished areas -there is a positive relationship between diseases and butterflyfishes -removal of butterflyfish predators=higher butterflyfish population=increase abundance of disease bc butterflyfish act as a vector

Answer 49

-increased CO2 level->increased greenhouse gas->increased sea temperature->increase coral stress and bleaching

Answer 50

-CO2 becomes limiting (carbon limited) -energy from sunlight must go somewhere -reactive oxygen species (ROS): damage cellular mechanisms of corals -light and heat interact to drive bleaching -bleached corals are not dead->they will starve to death if they do not recover their symbionts

Answer 51

-temp of water = very warm -nearly 100% mortality of corals—from coral dominant to coral depauperate system -system becomes dominated by macroalgae

Answer 52

1997-98 -worst global bleaching on record -all ocean basins -strong El Niño/La Nina cycle ~16% of global reefs say almost complete mortality -El Nino in Indian Ocean (1998): 80-90% of corals bleached and died, 20% of corals died worldwide

Answer 53

-wind moves from east to west -drives equatorial currents -drives strong up welling in East Pacific (cold water moves from deep to surface) -high pressure in east, low pressure in west -higher volume of water in west compared to east -warmer water in west, cooler in east

Answer 54

-slower winds -slower equatorial currents -no longer have upwelling in east and high water levels in west->these levels that were in the west, migrate to east and warm the whole Pacific

Answer 55

winners: slow growing, encrusting corals losers: faster growing, branching corals -less tissue = lower survivorship -more tissue = more photoproductive, more energy reserves -differing symbionts -bleaching can also reorganize communities

Answer 56

One week at a time 1 degree C above summer average max temp -average max at Moorea = 29, then 1 week at 30= 1 DHW -takes into account intensity and duration -2 DHW = 1 wk staying at 2 degrees OR 2 wk at 1 degree -DHW over 4 C= significant coral bleaching -DHW over 8 C = widespread bleaching and some mortality

Answer 57

DHW <8 = all good, very little coral mortality DHW >8 = die

Answer 58

1994: humans pressures = larger threat than climate change 2000: climate change = larger threat than human pressures

Answer 59

-one of the strongest El Niños on record -a mass bleaching event followed -bleaching events are becoming more intense and more frequent -frequency now= 4-6 years

Answer 60

-GBR—decades decline in corals-over 50% loss -coincident with COTS outbreaks increase in bleaching -most mortality came from COTS and cyclones

Answer 61

-2014-2017 -started in Republic of Kiribati, Kiritimati Island (2013)—in the very middle of alter 2 (most severe bleaching) -in 2016: 90% coral loss

Answer 62

-mass bleaching GBR 2016 (most severe) -cyclone Winston saved South GBR by mixing up water and cooling it down, also making the water more turbid and cutting down on light intensity -increase in DHW=increase in coral bleaching (very strong correlation) -estimated at least 50-60% coral loss in North GBR->some reefs had over 90% loss -areas became dominated by macroalgae

Answer 63

-75% of fish spp declined -50% declined by less than 50% -coral bleaching most affects the fish that are most associated with corals -1998 bleaching event: cryptobenthic fish community changes after bleaching ,75% of Acropora and 100% of Montipora -no change in fish spp richness/diversity (# of types of fish didn’t change) -winners: generalist planktivores (damselfish rely on food from open ocean, not super dependent on corals) -losers: coral specialists (gobies strongly depend on live corals)

Answer 64

-corals physical structure doesn’t change when bleached -they visually change (lose color), making it easier for predators to see the prey

Answer 65

-Eliat, Red Sea -fish were infected with streptococcus iniae (a bacteria) -fish started dropping dead (ocean floor was covered with dead fish) -piscivores and grazers seemed to be the most susceptible -rapid increase in sea temp, compromised fishes’ immune system, making them more susceptible to infection

Answer 66

-Holocene: temperature was increased, Acropora distribution was more north -present day: temperature was decreased compared to Holocene, Acropora distribution was more south -recently Acropora have been discovered in the north due to the increase in sea temperature

Answer 67

-range shifts moving water water spp poleward -many herbivores follow, migrating towards temperate reefs -alter herbivores-algal interactions, migration of herbivores to temperate -increase in herbivores and water temp (macroalge doesn't have defenses against tropical herbivores) -ideal place for coral larvae to settle, little compatition from algae

Answer 68

Resilience: ability of a population to recover after suffering a disturbance Resistance: ability of a population to withstand a disturbance

Answer 69

Coral reefs shifting from a coral dominant ecosystem to a macroalgae dominant ecosystem

Answer 70

Natural: -huricanes/cyclones/typhoons -COTS Anthropogenic: -bleaching -disease -sedimentation -dynamic fishing -ship grounding

Answer 71

-wave energy greatest in shallow water -reef crests seriously affected (branching corals) -may facilitate asexual reproduction—fragments from colonies -impacts down 20-30m and occasionally 50m Damage: -colonies shatter, fragments damage neighbors -deeper corals are damaged by shallow corals ‘falling’ -bioerosion weakens colonies, increasing hurricane damage -tissue damage from sand scouring -secondary mortality (disease, predation)

Answer 72

-herbivores often control macroalgal growth -reduces abundance of magroalgae -whether magroalgae develops depends on grazing pressure -macroalgae can overgrow adult corals (but rare) -macroalgae can increase after coral mortality (extra space to colonies) -macroalgae prevents coral recruitment

Answer 73

-decades of overfishing -Hurricane Allen (1980) -sea urchin disease —causing high urchin mortality -Hurricane Gilbert (1988) -White band disease on Acroporids

Answer 74

A)healthy reef (high fish, modest urchins, coral dominated) B)semi unhealthy reef (low fish, high urchins—herbivory is maintained, moderate coral-algae ratio) C)unhealthy reef (aka modern-day Jamaica) (low fish and urchins, high algae, low coral)

Answer 75

-For given environmental conditions only 1 state possible -relatively easy to move from one state towards another

Answer 76

For given condition, could be either state -takes big change of conditions to make state change significantly -very hard to move it back -‘flip and lock’ -alternative stable state -‘unstable’ btwn states, so state heads towards one or the other

Answer 77

Low resilience: small disturbance drives shift to algal state High resilience: high herbivores, can withstand more frequent and larger disturbances

Answer 78

Draw diagram

Answer 79

An increased number of disturbances can reduce coral cover enough that the reef is pushed past the threshold and makes it very difficult for the reef to recover to being coral dominant -high grazing would be the only reason why a reef can survive multiple disturbances

Answer 80

Initially was high coral cover and grazing 1. Hurricane Allen (1980): resulted in decrease in coral cover, didn’t cross over threshold, started to recover due to high grazing 2. Urchin disease (1983): wiped out a lot of urchins, loss of herbivory, pushed past threshold, system became algal dominant, still has highish coral cover 3. Hurricane Gilbert and White band disease on Acroporids (1988): significant decrease in coral cover System remains at low grazing (no urchins) and low resilience -could recover if there was a drastic increase in grazing