13 rocky intertidal corals whales(1)

8/10/2019 13 Rocky Intertidal Corals Whales(1)

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Intertidal Ecology

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Outline1. Zonation

upper limit set by physical environmentlower limit set by biological interactions

competition predation

2. Species Diversity within a Rocky Intertidal Community keystone predator ( Pisaster )

set by periodic disturbance3. Trophic Cascading Effects

Sea Otters and Kelp Forests Example

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Vertical Zonation the hallmark of the intertidal zone

Communities are divided into distinct bands, or zones, at characteristicheights in the intertidal.

Species are not randomly distributed throughout the intertidal zone, but ratherare arranged within relatively narrow vertical ranges. The zones look like sharply divided belts easily distinguished by the colors of theassemblage (i.e. community) of organisms that live there

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Physical Stresses: Often set Upper Limit to SpeciesDistributions:

1. Desiccation

2. Temperature 3. Food Availability4. Wave Energy

5. Salinity

6. Dissolved Oxygen

Stress Factors

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1. Competition for Space note that space on a rock to attachis the valuable resource that is inshort supply in the intertidal

2. Predation

Biological Interactions: O ften set Lower Limit toSpecies Distributions:

Biological Factors

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The Cause of Zonation: A Simple Barnacle Example

1. The Upper Limit of both species (grey and rock barnacles) is determined by emersion; larvae that settle too high in the intertidal dry out and die ( physicalfactor ).

Little grey barnacles can tolerate drying better thanrock barnacles , so they settle higher in the intertidal.

2. At Lower Levels , where the rock barnacles cansurvive, the rock barnacle out competes the little grey

barnacle for space ( biological factor ) and this sets to lower limit for the little grey barnacle.

3. The Lowest Limit of the adult rock barnacles isdetermined by competition from mussels, and

predation by whelks or sea stars ( biological factors ).

Grey Barnacles

Rock Barnacles

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Summary:

General Rule of Zonation upper limit at which a species can

occur in the intertidal is usuallydetermined by physical factors ,

lower limit is usually determined by biological factors

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Species Diversity within a Rocky IntertidalCommunity

1. Keystone Predators

2. Intermediate Disturbance

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Starsh Predation:

1. Mussels can out compete most of the otherintertidal organisms for valuable space

2. Pisaster (Starsh) predation sets the lowerdistributional limit to mussels and below thisdistributional limit other species can settle in

3. The removal of Pisaster allows mussels to takeover and this leads to a decrease in thecommunitys species diversity (just musselsremain).

Sets Lower Limits of Mussel Distributions inRocky Intertidal

Leads to Higher Species Diversity within aRocky Intertidal Community

(Paine, 1966)

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Keystone Predators: Predators that have effects on their communities

that are proportionately much greater than their abundance wouldsuggest are know as keystone predators

A rocky intertidalstarsh called Pisaster is a classic type ofkeystone predator

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Massive Die-Off of Starsh Along the US Westcoast

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1. Physical disturbance (e.g., wave energyfrom storms and log damage) can openup gaps or patches in the rockyintertidal.

2. Intermediate Disturbance Hypothesis - disturbance maximizes species diversity

by periodically removing competitivelydominant species and allowing lesscompetitive species to reestablish

themselves

Physical Disturbance Can Also Regulate Species Diversity within

a Community

Note : Too much disturbance keeps the rock bare with few species. Too littledisturbance allows the dominant competitor for space to take over and form amonoculture (single species)

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Trophic Cascade:

Sea Otter-Kelp Forest Example1. Sea Otters eat sea urchins

2. Sea urchins are herbivores thateat tiny young kelp (before they

grow large). 3. Removal of sea otters allows sea

urchins to grow to highabundance

4. Low abundance of sea otters leads to high abundance of seaurchins and low abundance ofkelp forests 2004 KenAshman

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Summary1. Zonation

upper limit set by physical environment

lower limit set by biological interactions competition

predation 2. Species Diversity

Pisaster (starsh) - A Keystone Species

intermediate disturbance

3. Trophic Cascade Effects Sea Otters and Kelp Forests

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Coral Reefs

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Coral Anatomy

Calcium Carbonate Support StructureNOTE: the process of building a calcium carbonate reef structure layer-by-layer is a very slow process:


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Zooxanthellae arechlorophyll-containing algalsymbionts that live in the

tissue of the coral polyp

Corals receive 60- 90% of their overall nutrition from

photosynthetic-derived products!!!

Coral Energetics

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Limits to Coral Net Growth

1. Temperature

2. Sunlight

3. Space to Grow 4. Predation

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Temperature: Limits Coral Growth to Tropical Latitudes Optimal 26-28C

Restricted 18-36C

Sunlight: Limits Coral Growth to a depth range extending from the oceansurface down to maximum of about 25 metersLight required for zooxanthellae to photosynthesize

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http://upload.wikimedia.org/wikipedia/commons/thumb/c/cb/20_Grad_Isotherme.png/1024px-20_Grad_Isotherme.png

Boundary for 20 C Isotherm : Most corals live within this boundary. Note thecooler waters caused by upwelling on the southwest coast of Africa and off thecoast of Peru.

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Location of Coral Reefs

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http://www.nature.com/scitable/knowledge/library/coral-reefs-15786954

Because corals rely heavilyon the photosynthesis ofZooxanthellae, they have adepth limit, set by light

levels, below which theycannot grow effectively -

this limit is typically about25 meters

Depth Limit Where Corals Can Grow is Set by Light

Requirements

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Coral Reef Formation1. A new island forms (e.g., mantle hot spot

or ocean-ocean plate collision) and a fringing reef develops in shallow sunlit waters close to shore of the island

2. The island slowly sinks with age (crustcools and thins) and at the same time thecoral slowly upward by slowly secreting itscalcium carbonate support structure layer-

by-layer - this eventually forms a barrierreef .

3. At time point the entire island is submergedand all that is left is the reef - referred tonow as coral atoll . http://www.nature.com/scitable/knowledge/library/coral-reefs-15786954

fringing reef

barrier reef

coral atoll

new island

l i

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NOTE: If the island sinks too fast , or sealevel rises too fast , and the reef cannot keepup with its upward growth , it eventually stopsgrowing because it becomes too submerged in

deep/dark waters

These dead reefs are referred to as drownedreefs

Coral Reef Formation

http://www.nature.com/scitable/knowledge/library/coral-reefs-15786954

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Corals Compete for Space: With Other Corals and With Macroalgae

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Corals Competing with Other Corals: Sweeper Tentacles

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Corals Competing with Other Corals: Sweeper Tentacles

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The competitiveadvantage for takingover space is shifted in

favor of macroalgae when nutrients fromagricultural activitiesrun off the coast andonto coral reefs

Competition with Macroalgae

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Predation by Crown of Thorns Starsh ( Acanthaster )

1. This starsh is animportant predator ofcorals

2. One of the main sources ofcoral mortality

3. Eutrophic conditionsincrease phytoplanktonabundance that enhances

the growth of Acanthaster larvae that eventually leads to large increases inabundance of adults andsubsequent high coralmortality

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Coral Bleaching1. It is the zooxanthellae algae that give

corals all of their beautiful naturalcolors

2. Coral bleaching is the name given to anevent where corals expel theirsymbiotic zooxanthellae algae due toenvironmental stress such as unusually

warm water

3. Corals can recover and regain theirzooxanthellae if the stress is small or

short-lived (a couple of weeks) 4. Coral death follows if the stress is

extreme and/or prolonged.

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http://www.reefpix.org/albums/album62/DSCN1595.jpg

Corals are extremely sensitive to rises is sea temperature. Just 1 oC above normal for a period of a few weeks is enough to result in coral beaching.

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Regions Were: Caribbean, Atlantic coast of South America, Western Pacic, Central Pacic, EasternPacic, North Pacic, South East Asia, North East Asia, Western Indian Ocean and Eastern Indian Ocean.Data collected from over 3800 bleaching records from nearly 100 countries in the ReefBase bleaching reportdatabase (http://www.reefbase.org, Dec 23, 2002).

Number of Regions Reporting Coral Bleaching Worldwide

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The global Average Loss of Coral is Now at About 27% !!!

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Hoegh-Guldberg 1999

Projected Rise in Sea Surface Temperature Relative to Coral Bleaching ThresholdDenoted by Solid Horizontal Lines

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Hoegh-Guldberg et al. (2007) Science Vol. 318. pp. 1737 - 1742

1. Increases in CO 2 in the atmosphere lLeads to Increases in oOceanacidity

2. Projected Increases in ocean aAcidity lLead to slowing of calciumcarbonate precipitation and/or eventually coral dissolution

Ocean Acidication

3. An atmosphere above 480 ppm is Expected toEnhance Coral Loss -

We are now at 400ppm

4.Note that Twice Pre-Industrial AtmosphericCO 2 = 550 ppm

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Expected Scenario Of Reef Changes with Increasing Atmospheric CO 2

Hoegh-Guldberg et al. (2007) Science Vol. 318. pp. 1737 - 1742

NOTE : The atmospheric CO 2 concentration is currently at 400 ppm and going up by about 3 ppm each year - so it will reach 450 in about 15 years

375 ppm +1 oC

>500 ppm > +3 oC

450-500 ppm +2 oC

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1.Coral reefs around the world are being degraded at an accelerated pace due to the combined effects of local-scale stressors caused by land-based pollution and by global-scale stressors due to a

warming planet and increased ocean acidication.

2.It is now widely recognized that local-scale stressors on coral reefsshould be minimized as an immediate means of offsetting increasesin global-scale stressors.

3. Managing local water quality conditions to alleviate the pressurefrom global-scale stresses is now a top reef management priority.

Overall:Coral Reefs Around The World Are In Rapid Decline...

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Whales

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1. Whale Evolution

2. Feeding Modes

3. Vocalizations

4. Migration

5. Sound Pollution

6. Whaling

Outline

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Pakicetus hoofed-mammal that is sometimes classied as the earliest whale. It livedaround 53 million years ago (after the age of dinosaurs). It looked rather like adog/wolf with hoofed feet and long, thick tail. The shape of the ear region in the Pakicetus skull is highly unusual and onlyresembles the skulls of whales. The special ear bone feature is diagnostic forcetaceans and is found in no other species.

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Ambulocetus ("walking whale") was an early cetacean that could

walk as well as swim. It lived during early Eocene some 50-49 million years ago. It is a transitional fossil that shows how whales evolved from land-living mammals.

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Rodhocetus lived in the Middle Eocene 46-47 million yearsago, and was still able to walk on land though not very well.

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Dorudon lived during the Eocene about 40 to 36 million years ago.Dorudon reached about 5 meters in length and was a carnivore. Theoverall look of Dorudon was very similar to the modern whale.Dorudon lacked the ability to go on land . It had tiny hind legs that

barely protruded from the body.

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Basilosaurus lived at about the same time as Dorudon in the Eocene 40 to 37million years ago. This creature had a pair of very small hind legs, about 2 feet

long. Its jaw was around 5 feet long and was equipped with cone shaped teethin the front and triangular shaped teeth in the back .

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Evolutionary Divergence of Baleen Whales From Toothed Whales

1. All Baleen Whales ( Mysticetes) are large lter-feeders

2. The exact means by which baleen are used differ among species:

gulp-feeding skim-feeding

bottom plowing

3. The rst members appeared about 35 million years ago . Thesechanges may have been a result of worldwide environmental changeand physical changes in the oceans.

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Mysticetes

(Baleen)

Odontocetes (Toothed)

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Feeding Modes

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Orca (Killer) WhaleOdontocete (Toothed)

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BBC Blue Planet

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Baleen Whales

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Baleen whales feed bygulping large quantities ofseawater and thensqueezing the water

through the baleen lter to retain krill and smallsh.

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Swimming with aHumpback (Baleen) Whale

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Whale Migrations

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Pacic Humpback Migration

1. Summer Feeding at high

latitudes with longday length and lots

of biological productivity

2. Winter Calving at low

latitudes - usually warm, but low orno food

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Global Humpback Migration

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Pacic Grey WhaleMigration

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North Atlantic Right Whale Migration

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Vocalization In WhalesOdontocetes (toothed whales) 1. Produce rapid bursts of clicks and whistles 2. Do not make the long, low-frequency, sounds known as the whale song .3. Single clicks are generally used for echolocation

4. Collections of clicks and whistles are used for communication. 5. The multiple sounds themselves are produced by passing air through a

structure in the head rather like the human nasal passage.

Mysticetes (baleen whales)1. Often make the long, low-frequency, sounds known as the whale song .2. Have a larynx that appears to play a role in sound production, but it lacks

vocal cords and scientists remain uncertain as to the exact mechanism.

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1. While many toothed whales are capable of using echolocation to detect the size and nature of objects (e.g., prey), this capability has never beendemonstrated in baleen whales.

2. Given the poor visibility of aquatic environments, and the fact that sound travels so well in water, simple sounds may play a role in navigation . Forinstance, the depth of water or the existence of a large obstruction aheadmay be detected by loud low frequency noises made by baleen whales.

The complex and haunting sounds of the Humpback Whale (and some Blue Whales) are believed to be primarily used in sexual selection during matingseason, but the simpler sounds of other whales have a year-round use .

Mysticete Vocalization:Sexual Selection or Navigation

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Bowhead Whale - Shallow, Coastal ArcticSong (two voiced) normal speed

Slide- Kip Reddington

Christopher W Clark

Time

F r e q u e n c y

Spectrograms are used to visualize the whale vocalization

Christopher Clark (Cornell Lab of Ornithology)

1. Time on the x-axis

2. Frequency on the y-axis

3. Loudness is denoted byBrighter Colors

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Time

F r e q u e n c y






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Sources of Anthropogenic Sound in the Ocean

1. Commercial Shipping Engine and Propeller Noise

2. Naval Operations Low Frequency Active Sonar

3. Oil Exploration Seismic Surveys with Explosive Air Guns/Cannons

Repeated Every Ten Seconds, 24 hours a day, For Days and Weeks at a Time

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Bowhead Whale - Shallow, Coastal ArcticSong (two voiced) normal speed

Slide- Kip Reddington

Christopher W Clark

Time

F r e q u e n c y






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Ambient Ship Noise

Low BoatTrafc

High BoatTrafc


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1. Acoustic Habitat is no different than spatial habitat and must be preserved.

2. Noise Pollution is every bit as destructive as other forms of morefamiliar marine pollution (oil, nitrogen, plastic)

Dr. Christopher Clark Cornell Lab of Ornithology...

Noise Pollution

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Whaling...

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Whaling An international convention on whaling culminated in the signing of theInternational Convention for the Regulation of Whaling (ICRW) in 1946 The aim is to "provide for the proper conservation of whale stocks and thus make

possible the commercial whaling and the orderly development of the whaling

industry".

The International Whaling Commission (IWC) was set up under the terms of theICRW to make decisions on quota levels based on the ndings from the ScienticCommittee of the IWC . Countries which are not members of IWC are not bound

by its regulations and conduct their own management programs.

The members of the IWC voted on 23 July 1982 to apply a moratorium to allcommercial whaling beginning in 1985...

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Japan continues to whale by claiming its whaling operation is now for scientic purposes . The IWC allows lethal scientic whaling, but only when it addresses questions vital to management. Numbers vary each year, but on average it is close to 1,000 Minke(not-endangered), 50 Fin (endangered) , 50 Humpback (endangered) and 5 Sperm(endangered) whales each year . NOTE: The IWC found the Japanese research to be unnecessary, and that the same ends could be accomplished by non-lethal methods, but Japan continues this practice

Norway registered an objection/reservation when the 1982 IWC whalingmoratorium was signed, and was thus not bound by it. In 1993 Norway decided toexercise its reservation against the moratorium and resumed domestic commercial whaling.They now take about 600 Minke (not-endangered) whales each year

Iceland issued licenses in October 2006 for a commercial whale hunt in addition to itscontinuing hunt for scientic purposes. Iceland has an exemption to the moratorium

through the reservation it made in 2002 . They take about 150 Fin (endangered) and200 Minke (not-endangered) whales each year .

13 rocky intertidal corals whales(1)

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