Marine Ecology Exam 2

Deposit feeders

Ingest sediment and get most of their nutrition from microbes

Steller's sea cow

Was hunted to extinction

Characteristics of Polar seas, Antarctic (subtidal/pelagic)

- There are diatoms and krill dominating the planktonic niche which is common in these cold regions

- Also the dominance of marine mammals is more common in cold regions, Specifically seal presence as well

Effects hunting of whales may have had on the rest of this food web

- Reduced nutrient cycling, Whales feed at depth and defecate at the surface, providing iron and nitrogen that fertilize phytoplankton. Reduced whale populations decreased this nutrient availability, resulting in less phytoplankton.

- Declining Krill and Food Web Collapse: In the Southern Ocean, the slaughter of baleen whales was linked to a decline in krill populations, contradicting the idea that more whales mean more food for other species.

- Loss of Deep-Sea Biodiversity ("Whale Falls")

Polar bears

- Family Ursidae

- Polychlorinated biphenyls (PCBs), industrial chemicals that accumulate in marine life

- Threatened by habitat loss

- Blubber, semi-aquatic

Sea Otter

- Most aquatic carnivore

- Family Mustelidae

- No blubber, relies on thick fur to keep warm, denser fur than any other mammal

- Nostrils and ears can close

Pinnipedia

- Seals and sea lions

- Layer of blubber

- Slow reproduction; long-lived adults

- Many are polygamous and territorial on breeding grounds - largest, most aggressive males collect a harem

- long eyes, optimized to see prey underwater

- short snout, maintains heat

Sea lions and fur seals

- Have external ears

- Family Otariidae

- Have dense layer of hairs closeto the skin, Traps air, Waterproof

- Can move rear flippersforward (rotate pelvis), and front flippers forwardso can walk on land withall 4 limbs

Family Otariidae

Sea lions and fur seals

Family Phocidae

True or earless seals

True or earless seals

- Eats mostly fish and squid

- Family Phocidae

- Have rear flippers that can not be moved forward On land

- Can overheat -- lose heat bywaving flippers in the air whileincreasing blood flow to theextremities

Family Odobenidae

Walruses

Walruses

- Huge body, sparse hair, coarse mustache, robust canines / tusks (sexual characteristic/ sediment probing)

- Feeds mostly on benthic invertebrates, like clams and worms

- Family Odobenidae

- Can use tusks to staysuspended at air hole

Order Sirenia

- Manatees, dugong, extinct Steller's sea cow

- Lots of blubber, Front flippers but no rear limbs

- Only 4 species left, and all are in danger of extinction

-

Vessel collisions, Cold weather, Poor water quality, Harmful algal blooms, Loss of seagrass beds

Reasons for Manatee population decease in Florida

Order Cetacea

- Whales, dolphins and porpoises

- Muscular tail ends in a pair of fin-like horizontal flukes

- Nostrils are on top of the head

- larger animals have less SA/V and lose heat less quickly

- have a very thick layer of insulating blubber

- Bradycardia

Bradycardia

- Slowing of heartbeat during dives

- Order Cetacea

- The blood supply is cut off from some organs during dive (some muscles, digestive system, kidneys) blood is shunted to the CNS [brain]and heart)

Diving and locomotion in Cetacea

- Higher oxygen capacity per volume of blood (more hemoglobin)

- Muscles contain myoglobin, better at storing oxygen than hemoglobin

- Dark color of whale meat is due to the presence of both myoglobin and hemoglobin, as well as lower amounts of fat within the muscle

Osmotic Regulation Cetacea

- Whales derive most of their water from metabolic break down of their prey

- Make very concentrated urine

Toothless/Baleen Whales

- Have two nostrils and a symmetrical skull

- Have rows of flexible, fibrous plates (baleen) that hang from the upper jaws

-Myoglobin pigment better at sorting oxygen than hemoglobin

- Higher oxygen capacity per volume of blood allows to maximize oxygen for deep diving

- Mysticeti

Grey whales Role in the Ecosystem

- When take mouthfuls of sediment leave large, irregular depressions and can be a major structuring force of benthic communities

- A baleen whale that feeds on benthos

Cetacea vocalizations

- Some whales (humpbacks, finbacks and blue whales) create low frequency sounds that can be detected hundreds of km away

- Some humpback songs may be used to attract mates or mediate male-male interactions during breeding season

Cetacea Migration

- Many baleen whales feed in the summer in the polar regions; during winter they migrate to warmer water; breed and remain until calves put on blubber layer (grey whales - 11,200 miles round trip)

- Whales may have a geomagnetic sense

MELON

- fat-filled structure, acoustical lens

- 40% of body length in sperm whales

Echolocation

Sounds produced by movement of air through nasal passage and associated air sacs

Ambergris

- Squid beaks and other undigested food accumulates in the gut of sperm whales as globs of sticky material

- An ingredient in fine perfumes

Whaling

- Products: blubber - 'train oil' for soap and lamp oil; baleen (whalebone); meat; ambergris, spermaceti

- First to be seriously depleted was the north Atlantic right whale

Marine Mammals Protection Act (MMPA)

- 1972 (US)

- Prevents taking (hunting, capturing, killing, harassing)and prohibits most importations of marine mammals and products using them

- Defined the objective of management not in terms of how many could be harvested, but how many were left in the wild

Status of Marine Mammals (IWC)

- Whaling in Japan and Norway

- Aboriginal subsistence whaling

- Grey whale, protected since 1947, has made a comeback

- Numbers of blue whales increasing

Macrobenthos

benthic organisms that are greater than 0.5 mm

Meiobenthos

Benthic organisms (animals or plants) 0.1 to 0.5 mm in size

Microbenthos

less than 0.1 mm; protozoa and bacteria

Deposit feeders

- Ingest sediment

- Digest organic matter and microbial organisms

- Abundant in areas with lots of organic carbon deposition (detritus)

Suspension feeders

- Capture particles from the water

- Often in areas of higher flow

Sorting

Estimate of range of particle sizes

Sand Burrowing

not compressible; must push sand aside and compress water in interstices

Mud Burrowing

Particles often adhere to each other

Hydromechanical burrowing

- Muscle contraction working against rigid, fluid filled chamber (skeleton)

- Form penetration anchor first to allow further extension of body into sediment

- Form terminal anchor to allow pulling of rest of body into the sediment

- May propagate/continue cracks that form in sediment

Thixotropy

Physical phenomenon of a gel becoming liquid when pressure is applied or it is stirred - saturated sand agitated by a burrowing organism acts like a liquid and it takes less energy to burrow than one might expect

Mechanical displacement

digging

Oxygen profile in sediment

- Strong vertical chemical gradients

- Caused by lack of water flow in soft sediments and biological activity in sediments

- Oxygenated in surface; rapid decline due to aerobic respiration

RPD

- Redox (reduction/oxidation) potential discontinuity

- Chemical boundary between oxygenated and reduced sediments

Hydrogen sulfide

- In anoxic zone

- Produced by sulfate- reducing bacteria

Light brown oxidized layer

- Aerobic photosynthesizers and heterotrophic aerobic bacteria

- Near the surface of the sediment

Gray Layer

- Transition between light brown oxidized layer and reduced black layer in ocean floor sediment

- H_2S oxidizing bacteria at RPD

Reduced Black Layer

- Heterotrophic bacteria that use terminal electron acceptors other than oxygen below RPD including Sulfate reducing bacteria

- break down organic matter using sulfate as terminal electron acceptor and reducing it to H_2S

- In deeper sediments get methanogenic bacteria that produce methane as a byproduct of anaerobic respiration

- Surface

- Within sediment

- Tentacles

- Swallowing sediment

- Siphoning

Types of deposit feeding

Microbial stripping hypothesis

- Deposit feeders are most efficient at digesting and assimilating benthic microbes (diatoms, bacteria)

- Some sediments have low amounts of living material, so deposit feeders may process large amounts of low quality sediment to get adequate nutrition

POM

- Particulate organic matter

- Fragmentation, Leaching, Microbial decay

- Deposit feeders help stimulate decomposition by fragmenting Particulate organic matter, and increasing microbial activity (even though they then eat the microbes)

Phytodetritus

- Falls from surface water when phytoplankton die and sink

- Can be big seasonal pulse after spring blooms

- Easy to digest and high nutritional quality (high protein and lipid)

- Degrades over time

Coprophagy

consumption of feces

Biogenically graded beds

- Produced by actions of some deposit feeders

- select fine particles, leaving coarse behind

Passive suspension feeding

- Protrude feeding organ into current and collect particles

- e.g., some hydroid cnidarians

Active suspension feeding

- Create a feeding current

- Mostly a low Reynolds number situation

- e.g. Bivalve, Barnacle

Infaunal Suspension Feeding

- Organism buried in sediment, but can create current and bring in water

- Burrowing polychaetes (use specialized parapodia) and mollusks (ciliated gill, inhalant siphon, ciliated palp)

Hard surface benthic habitat Sampling Issues

- Harder to sample quantitatively

- Dredges that scrape the bottom

- Require direct observation and manipulation

Borers

Rock boring clams, like Penitella, the flat-tipped piddock, can actually bore into rock along the rocky shores

Hard surface benthic habitats

- Strong current and drag

- Organisms that inhabit this habitat must be able to Adjust position, have Flexibility, or be Mobile

- Angle of rocky substrate is important, more algae on horizontal (light); more invertebrates on vertical

- Amount and quality of water column particles is important for these habitats, may cause Sedimentation

- Many suspension feeders

Microphages

Graze on benthic microalgae (e.g., diatoms, cyanobacteria....benthic biofilm)

Macrophages

Graze on benthic macroalgae (e.g., seaweeds) and higher plants (e.g., sea grasses)

Neritic zone

The shallow, nutrient-rich, and sunlit part of the ocean extending from the low-tide mark to the edge of the continental shelf, typically reaching depths of up to 200 meters

Subtidal Environmental Condition

- More variability than open ocean/deep sea; less than intertidal

- Very productive, high nutrients, little stratification, runoff from land

- Wave action (but less than in intertidal zone)

- Temperature, fully mixed water column; seasonal variation

- Debris, runoff, kelp, seagrass, high production of plankton can reduce light penetration

- High production of attached primary producers (kelp and seagrass)

Most subtidal benthic habitats

Are areas with soft sediment, dominated by infauna

Polar Seas

- Drastic changes in photoperiod over the year

- Physical conditions of the Arctic and Antarctic

- Wave action is not as important as in other benthic communities, b/c Ice scours the shoreline and benthos

Anchor ice

- Forms on the bottom to about 30 m

- If it lifts from the bottom it can carry organisms up to the sea ice, where they become entrapped

Antarctic

- High biomass (10-100X than in the arctic)

- Greater benthic species diversity and endemism than in the arctic

- Mostly epifauna (Mostly hard (rock) substrate)

- Fish less important, many fish are endemic

- Icefish have 'Antifreeze', Specialized physiological adaptations to cold

- Lack of shell crushing predators

- Many birds at sea ice edge

Arctic

- Has many forms of Atlantic origin

- Mostly infauna (lots of sediment)

- No specialized endemic fish

- Few birds at sea ice; birds differ longitudinally

- Lots of copepods

Mysticeti

Baleen whales

Odontoceti

- Toothed whales

- Asymmetrical head/melon (fat filled), nasal passages and air sacs allows for echolocation

Factors that limit productivity of phytoplankton in estuaries

- Light penetration, because there is high turbidity so the suspended particles block the phytoplankton's ability to photosynthesize

- Rapid flushing rates can move plankton out of estuary faster then they can grow

- Nitrogen is often limiting

Krill importance Antarctic ecosystems

- They are large zooplankton, but are herbivores, and so can be very efficient links at passing energy phytoplankton

- They are good at feeding on diatoms under the sea ice

- Because they are large and accumulate PUFAs (essential fatty acids) they can be eaten by large organisms like whales and fish and are an efficient trophic link

The benthos is dominated by infauna

Which is true of the Arctic Ocean?

Has extensive salt marshes

Under pristine conditions, which of the following describes a classic East Coast American estuary, but does not hold true for an estuary in Europe?

diffuse predation

When several consumers utilize the same resource, but no single consumer suppresses the resource population

It was the first legislation based on how many animals were in the wild rather than the number that could be hunted

The Marine Mammals Protection Act was novel legislation because

Pneumatocyst

a gas-filled bladder in Kelp

Pisaster

- A classic keystone predator

- Sea Star

Oysters

Important filter feeders in estuaries

Ursus maritimus

Polar bear

Spartina

A dominant salt marsh grass genus

Life cycle and life stages of a kelp

- Alternation of generations (diploid/haploid)

- The kelp is the asexual sporophyte stage and there is a small sexual stage

Zonation

What is this pattern of species being found in different predictable and easily observable parts of the intertidal called?

Diel vertical migration

Migration found in many zooplankton and fish where animals rise toward the surface at night and sink to depth during the daytime.