Ch 15

Life near the Surface

• LIFE NEAR THE SURFACE• Epipelagic• Surface to 200 meters

Zone facts

• Shallowest, warmest, best lit• Location of nearly all the primary production• Ocean currents carry epipelagic plankton into

shallow water where it is consumed by suspension feeders (animals, including filter feeders, that eat particles suspended in the water column

Zone facts

• Epipelagic fishes and zooplankton provide food not only to other marine communities, but also to land dwelling birds, mammals, and humans

• Epipelagic lacks deposit feeders (animals that eat organic matter that settles to the bottom) because there is no bottom

PLANKTON

• Plankton includes the drifting organisms that are found at most depths in the water column

• Thrive in epipelagic • Femtoplankton: too small to catch in a net.

Viruses. Also called virioplankton• Picoplankton: archaea and bacteria• Net plankton: can be caught in nets

Net Plankton

• Subdivided on the basis of size• Micro• Meso• Macro• mega

Plankton Division by Size

Plankton Division by Time in the Plankton

• Holoplankton – the entire life of the organism is spent in the plankton

• Meroplankton – only a portion of the life of the plankton is spent in the plankton (larval forms of fish, molluscs, crustaceans, etc) –seen at right

Another plankton division

• Phytoplankton: perform photosynthesis• Zooplankton: do not perform photosynthesis.

Zooplankton are the main source of nourishment for the young of many fish species, as well as much larger animals that strain the water for food. Zooplankton, which is made up of the larval stages of creatures such as echinoderms, eels, fish, mollusks, crustaceans and coral as well as tiny creatures like copepods, rotifers and krill, feeds almost exclusively upon phytoplankton.

• Together, phytoplankton and zooplankton make up the biomass known simply as plankton.

Phytoplankton

• Primary producers• Single celled or simple chains of cells• Perform more than 95% of the photosynthesis

in the ocean• This accounts to nearly half the world’s

primary production and produces nearly half the oxygen in our atmosphere

Phytoplankton: Diatoms and Dinoflagellates

• Phytoplankton are traditionally represented by diatoms and by dinoflagellates because they are “net plankton”

Diatoms

Diatoms

• The Bacillariophyta are the diatoms• Cannot move in water under their own power• Silica shells• Reproduce by cellular division (asexual)• Extremely important primary producers• Can be pennate (elongate) or centric (circular)

Pennate and circular Diatoms

• 1:07 “beautiful diatoms”• http://www.youtube.com/watch?v=0z-zBy3U

QQE

Dinoflagellates

Dinoflagellates

• Able to swim• 1200 species with unique shapes reinforced by

plates of cellulose• Two, long flagella in the groove of the body• Reproduction by cellular division (asexual)• Prefer warm water: tropics• Many are known to be bioluminescent• With nutrients and warmth, they may bloom• “Red tides”, Pfiesteria

Dinoflagellates 4 minutes

• http://www.youtube.com/watch?v=o5ESHXKGBvA

Sponge Bob PLANKTON

• http://www.youtube.com/watch?v=4LCagXzuOTg

Journal Assignment

• “Red Tide”• Cause and effect• Page 338-339• An additional internet source• One full page

• The most dramatic effect of dinoflagellates on life around them comes from the coastal marine species which "bloom" during the warm months of summer. These species reproduce in such great numbers that the water may appear golden or red, producing a "red tide". When this happens many kinds of marine life suffer, for the dinoflagellates produce a neurotoxin which affects muscle function in susceptible organisms. Humans may also be affected by eating fish or shellfish containing the toxins. The resulting diseases include ciguatera (from eating affected fish) and paralytic shellfish poisoning, or PSP (from eating affected shellfish, such as clams, mussels, and oysters); they can be serious but are not usually fatal. About 2% are known to be toxic

Red tide

• http://www.youtube.com/watch?v=OUeAMzoKNWg

Red sea

• Why is the Red sea red?• Of course it's not actually red, but sometimes it

appears that way. Located between the East African coast and the Saudi Arabian peninsula, the Red Sea got its name because of a type of algae called Trichodesmium erythraeum, which is found in the sea. When these blooms of algae die off they appear to turn the blue-green color of the ocean to a reddish-brown

Cyanobacteria

• Oldest fossils…..3.5 billion years• Bacteria• Formerly known as blue green algae• Some can go through nitrogen fixation which

improves growth in low nutrient conditions• Also an extremely important primary producer• Many grow in filamentous colonies with other

cyanobacterial cells• Stagnant pond water- toxic- death

Table 15.1

• Page 336

What is the largest species of Plankton?

TED: The Secret Life of Plankton

• http://www.ted.com/talks/lang/en/the_secret_life_of_plankton.html

• 6 minutes

Oceanic Research Group: Plankton Ocean Drifters 11 minutes

• http://www.ted.com/talks/lang/en/the_secret_life_of_plankton.html

Bioluminescence

• Production and emission of light by a living organism• Bioluminescence is a naturally occurring form of

chemiluminescence where energy is released by a chemical reaction in the form of light emission.

• creatures produce the chemicals luciferin (a pigment) and luciferase (an enzyme).The luciferin reacts with oxygen to create light. The luciferase acts as a catalyst to speed up the reaction, which is sometimes mediated by cofactors such as calcium ions or ATP.

• The chemical reaction can occur either inside or outside the cell.

• ATP(energy) + Luciferin (substrate)+ Luciferase(enzyme) + O2(oxidizer) == == light (photons)

• The energy in photons can vary with the frequency (color) of the light. Different types of substrates (Luciferins) in organisms produce different colors. Marine organisms emit blue light, jellyfish emit green, fireflies emit greenish yellow, railroad worms emit red , and Glow worms and fungi emit blue-green light ( appears blue to the eye close up but is actually in the green light spectrum ).

• Ninety percent of deep-sea marine life are estimated to produce bioluminescence in one form or another. Most marine light-emission belongs in the blue and green light spectrum, the wavelengths that can transmit through the seawater most easily.

Functions of Bioluminescence

• Camouflage• Mimicry• Attracting mates• Distraction• Repulsion• Communication• illumination

• Fish• Anglerfish• Cookie-cutter shark• Flashlight fish• Gulper eel• Lanternfish• Marine hatchetfish• Midshipman fish• Pineconefish• Viperfish

• Marine invertebrates• many cnidarians

– Sea pens– coral– Aequorea victoria, a jellyfish

• certain Ctenophores or "comb jellies"• certain echinoderms (e.g. Ophiurida)• certain crustaceans

– ostracods– copepods– krill

• two species of chaetognaths• certain molluscs

– certain clams, bivalves– certain nudibranchs, sea slugs– certain cephalopods

• Octopus – Bolitaenidae

• Vampire squid• Sepiolida• Teuthida

– Colossal Squid– Mastigoteuthidae– Sparkling Enope Squid

• Microorganisms• Dinoflagellates (e.g. Noctiluca scintillans,

Pyrodimium bahamense

Bioluminescence surfing

• http://www.youtube.com/watch?v=uUbIWqiynBY

Weird, wonderful world of biolumnescence 12:46

• http://www.ted.com/talks/lang/en/edith_widder_the_weird_and_wonderful_world_of_bioluminescence.html

Edith Widder: Glowing life in an underwater world 17:20

• http://www.ted.com/talks/lang/en/edith_widder_glowing_life_in_an_underwater_world.html

Table 15.1

• Nanoplankton– Coccolithophorids-shells of calcium carbonate,

thrive in low light and nutrient areas– Cryptophytes– Silicoflagellates-star shaped internal skeleton of

silica• Picoplankton– Cyanobacteria

“DT’s Live Phytoplankton Lab”

• Phytoplankton Lab

• Use page 341 in your text to answer question 5

Zooplankton

• The first step in the flow of energy from phytoplankton is zooplankton

• They are herbivores• They are the vital link between phytoplankton

and the rest of the community

• Very few zooplankton are strict herbivores and those that eat phytoplankton also eat other zooplankton occasionally. Most are carnivores

• “Night swimmers”- deeper water during the day and come up at night

Most common: protozoans

• Eat picoplankton and nanoplankton, which are the most abundant phytoplankton

• Without protozoans, much of the primary production in the epipelagic would go unutilized

• Most important protozoans are flagellates (move with a flagella)

• Protozoan grazers: ciliates, foraminiferans, radiolarians

Types of Zooplankton• Nanaplanktonic flagellates• Cnidarians (jellyfish)• Rotifera (• Chaetognatha (arrow worms)• Marine Gastropods• Polychaeta (annelid worms)• Copepods• Cladocerans• Krill (feed on diatoms. Krill is important food source for some

whales)• Insect larvae• Tunicates

krill

Krill

• small, shrimp-like crustaceans essentially the fuel that runs the engine of the Earth’s marine ecosystems- especially the polar seas since they prefer cold water

• Krill feed on phytoplankton• They are the main staple in the diets of

literally hundreds of different animals, from fish, to birds, to baleen whales.

• most of the life forms in the Antarctic would disappear without them

• Alarmingly, there are recent studies that show Antarctic krill stocks may have dropped by 80 percent since the 1970s. Scientists attribute these declines in part to ice cover loss caused by global warming. This ice loss removes a primary source of food for krill: ice-algae.

Krill …..FYI

• Scientists estimate that the total weight of all the Antarctic krill is more than the total weight of all humans on Earth.

• Krill can live for TEN years!!!!!

BBC- Whale hunting Krill 3:50

• http://www.youtube.com/watch?v=yMxY4c5SeIs

Happy Feet 2: Krill Free Will 2:22

• http://www.youtube.com/watch?v=01Runa3neb0

• 1:20…..another clip• http://www.youtube.com/watch?v=YAjPJnryzV

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Krill Lab

• Observe frozen krill under a dissecting microscope

Copepods

• Small crustaceans (Phylum Arthropoda)• MACROzooplankton• Most abundant members of the net zooplankton

(70% of the community)• Most numerous group of animals on EARTH• Carnivores (eating other zooplankton), but eat

some phytoplankton • Also eat detritus……..• (that’s a fancy word for organic waste)

• All copepods eat some phytoplankton• Bristles (bristly appendages) act as paddles

and are used to create water currents that draw individual phytoplankton cells close enough for the copepod to grab

Copepod Lab

• Wet mount living copepod samples

Nekton

• Large, strong swimmers such as fishes, marine mammals, squid, sea turtles, and penguins

• Practically all nekton are carnivorous, “predators”• Planktivorous nekton- eat plankton and small

fishes• examples: Whale Shark, Baleen whales, basking

shark• Most species eat other nekton instead of plankton

Life in the Epipelagic

• Living in this environment means finding ways to STAY AFLOAT

• This can be accomplished in various ways including air or lipid filled compartments (increases buoyancy) or by increasing surface area and “drag”

Increasing Buoyancy• Some organisms increase buoyancy by containing

droplets of compartments of lipid which tends to float

• Such organisms include diatoms, copepods and many larval forms

• Other organisms trap air in various structures or compartments to increase buoyancy

• Such organisms include cyanobacteria, cnidarians and even fish (swim bladder!)

Summary chart for “Increased Buoyancy” pg 342

1. Lipids2. Swim bladder3. Large, stiff fins and asymmetrical tails4. Control of composition of body fluids

Increasing Drag and Surface Area• Some organisms increase

their surface area by being flat (as seen top right)

• Others have a variety of spines or appendages to increase their surface area (bottom right)

• In both cases, increasing the surface area promotes “drag” or water resistance which helps keep these organisms afloat

The “Floaters”• Floating organisms are classified

as neuston (float just beneath surface) and pleuston (some “parts” float above and some “parts” float below surface

• At the top right, notice the pleustic Portuguese man ‘o war (Physalia) and the neustic Janthina (purple mollusc at bottom left of photo)

• At the bottom right, notice the pleustic Velella (page 343)

• Both Physalia and Velella use similar air filled sacs

Plankton Races

• Journal page 347– ADAPTATIONS

Predation and Protection from Predation

• Since organisms have virtually no places to hide, they must have other means for finding prey or avoiding being prey

• Fast swimming, protective coloration, migrations and a variety of sense organs are used to accomplish this

Predators and their prey

• 1. vision• 2. lateral line• 3. coloration, camouflage, countershading• 4. swimming• 5. vertical migration

Sense Organs

• Eyes – – eyes can be used to form images or simply to

sense light/dark or patterns– Most organisms is this environment have well

developed eyes– Eyesight is used to capture prey, avoid being prey,

find mates and stay in groups (as applicable)

Sense Organs – Remote Sensing

• Both cartilaginous and bony fish have a lateral line for remote sensing of water movement that can indicate prey or predators are nearby

Sense Organs – Remote Sensing

• Dolphins and other cetaceans use echolocation to navigate pelagic waters

• They also use this remote sense to find prey and avoid predators

Protective Coloration

• To blend in with their environment, organisms can have different types of protective coloration:– Countershading– Camouflage– Transparency

Countershading• In counter shaded

organisms, the ventral side of the organism is lighter than the dorsal side

• This aids the organism in “blending in” because if they are seen from above, their darker dorsal side blends in with the darker water below

• However, if they are seen from below, their lighter ventral side blends in with the better lit water above

Camouflage

• As an example, the sargassum fish, Histrio histrio, is an example of a pelagic organism that uses camouflage for protection from predators

• This fish looks very much like the Sargassum macroalgae it calls home

Transparency

• Another way to hide is to lack coloration completely

• This is the case with most jellyfish, comb jellies, salps, larvaceans, and many zoo- and phytoplankton

Swimming

• Epipelagic predators must be able to swim quickly to capture prey

• This is accomplished by a streamlined body to reduce drag, a strongly forked caudal tail to increase thrust and a narrow caudal preduncle to concentrate energy on the caudal fin

Vertical Migrations• The diagram to the right

shows the vertical migrations of copepods between day and night

• These copepods move into deeper waters during the day to avoid predators

• At night, they move back into shallower waters to feed on phytoplankton

• This predator avoidance comes with a cost – it takes more energy to migrate than to stay in one place

Protecting Ocean Predators

• Scientists estimate that 90% of many pelagic species have been fished out in the last 50 years.

• At the current rate we will have fished out all the large beneficial species by 2048

Discovery Channel • Top 5 predators of the Great Tide• In the Southern Hemisphere, the seasons are flip-flopped from those

in the North, with winter rolling around in June and July. When the weather shifts from hot to cold, the temperatures of ocean currents drop as well. Off the tip of South Africa, home to billions of sardines, chilly waters from Antarctica flow northward. In response, massive shoals of sardines retreat upward toward the South African coastline.

• Whenever the annual sardine run commences, it attracts a hungry following of both fish and foul. Dolphins, seals, breeder whales and others track down the migrating packs of plankton-eating sardines in search of a hearty winter feast. This fascinating feeding frenzy exhibits each predator's specialized hunting tactics and the integral role of the sardine run in the marine ecosystem of the Indian Ocean.

No. 5 Dolphins

• We don't often think of dolphins as predators, but the mammals gobble up sardines in droves. Using sonar communication, common dolphins collectively seek out sardine shoals and then alert other dolphins to the find. During the annual sardine run, dolphins form superpods of up to 5,000 members to chase down their silvery prey.

• Sardines usually swim deep in the water as another defense mechanism. When dolphins locate a shoal, they drive the fish toward the surface and corral groups of them together. The packs of sardines that dolphins round up are called bait balls. Isolating the bait balls in shallower depths also aids other predators, which trail the migration path of the palm-sized fish.

No. 4: Cape Gannets• When the predators of the great tide begin to attack at full force,

black and white Cape gannets dive headfirst into the ocean in a furious barrage of beaks and feathers. With their golden heads splashing into the water at nearly 60 miles per hour (96.5 kilometers per hour), the birds must take the plunge at precise angles to avoid injury or collision. To locate the deep-dwelling sardines, gannets follow dolphin pods.

• The breeding of the Cape gannets corresponds with the timing of the annual sardine run. More than 100,000 winged pairs inhabit Bird Island, off Cape Aghulas, on the eastern coast of South Africa. In the fall, thousands of chicks hatch, just in time to learn to fly, and leave the island to follow the sardine run. But once Cape gannets gorge on sardines, they must watch out for another lurking predator.

No. 3: Seals

• Cape fur seals will stalk the shores of Bird Island in search of vulnerable Cape gannet chicks. But it isn't a taste for avian flesh that compels the blubbery beasts -- it's the sardines in their small bellies. Colonies of Cape fur seals dot the beaches along the coasts of South Africa, southeastern Australia and Tasmania. As opportunistic feeders, the seals also take advantage of the annual sardine run that occurs close to the shoreline.

• As with the fledgling gannets, adolescent seals require the abundant winter sardines to fulfill their dietary needs. But when the two species encounter the same shoal of sardines, it's a risky proposition for the gannets to compete with the Cape fur seals for a meal

No. 2: Sharks

• Arguably the fiercest predator of the sea, sharks are known to attack sizeable fish, but the petite sardines also make the menu. Waiting until the dolphins have completed the task of forming bait balls of sardines, the cold-blooded sharks move in swiftly for the kill. When icy ocean currents push the sardines northward, the mammoth shoals will skim closer to the surface of the ocean near the coastline.

• Unlike the dolphins and Cape gannets, thousands of sharks can attack at will. But without the preformed bait balls, trapping the sardines proves more difficult for the finned hunters.

No. 1: Brooder's Whales

• Though smaller than humpbacks and sperm whales, the Bryde's whale is the largest — and most elusive — predator among those that stalk the annual sardine run. Often swimming alone or in groups of two or three, the 50-foot-long (15-meter-long) Bryde whale rarely reveals itself, barely raising its back out of the water to exhale from its blowhole. Yet millions of sardines trekking up the South African coast will summon the whale from its solitary lifestyle.

• Like sharks, the Bryde's whale arrives late on the scene of a sardine roundup. Then, with gaping jaws, the whale can consume 10,000 sardines, or an entire bait ball, in one gulp.

Ocean predators time line

• http://ocean.si.edu/ocean-over-time/top-predators-timeline

David Gallo: use clip for octopus 5 minutes

• http://www.ted.com/talks/lang/en/david_gallo_shows_underwater_astonishments.html

BBC Predator/Prey Relationships 48:17

• http://www.youtube.com/watch?v=NutiC6fie_I

Create a fish assignment

• Must exhibit all 5 adaptations epipelagic animals use to avoid predators

• Will be displayed in the class

Food webs and microbial loop

• SKIP

Patterns of Production page 350

El Nino