Marine Ecology Exam 1

Benthic

Bottom

Demersal

Things associated with the bottom

Pelagic

Open ocean (not close to shore)

Intertidal 

Shore that experiences tides

Subtidal

Below the effect of tides

Euphotic zone, PAR, UV

200 m deep. Some things can photosynthesize

PAR = Photosynthetic active radiation 

UV = ultraviolet 

Thermocline

Changes in temp

Halocline

Salt gradient

Pychocline

Density gradient

Cold water and warm water have different densities

Fresh water goes on top because it is less dense than salt water

Siddon & Wittman

Where is marine productivity the highest & why? Who does this producing mainly?

Along the coast

Higher nutrient availability due to terrestrial runoff and nutrients from deep water inflow 

shallow waters, warm, density of organisms high

Done by phytoplankton: diatoms

What are the challenges for marine organisms vs terrestrial?

1) Buoyancy

Organisms that photosynthesize or those that eat those that do need to be able to float to be on surface for sunlight 

Neutral bouyancy

Not floating, not sinking (staying wherever you are)

What is primary productivity & what influences it?

Photosynthetic organisms that take CO2 and produce sugars, biomass

Influenced by: 

sunlight

amount of photosynthetic organisms 

nitrogen, phosphorus availability (nutrients)

water

How would we measure productivity remotely?

infared maps, fluorescence (absorption of light)

Why do plankton need to photosynthesize?

light, warmth, nutrients

What do protrusions (points, edges, fins) do to drag? 

Lots of drag, sink slower 

What do cuddlefish, squids have that allows them to float?

Cuddle bone, squid pen: almost like foam but is a bone full ofairthat allows them to float (air sacs)

What do sharks have that allows them to float?

-No air sacs

Have a very fatty, oily liver (oil less dense than water) which allows them to float 

General anatomy differences between derived and ancestral fish

Derived: have a swim bladder, network of blood vessels can deflate/inflate, swim bladder w/ air

Ancestral: swim bladder connected to gut, not vascular system 

Viscosity

the state of being thick, sticky and semifluid in consistency due to internal friction. Measure of resistance to flow

Turbulent flow

Unequal pressure, swirly, foamy

Going around an object: part and rejion with pressure differences

Laminar flow

Smooth, parallel layers of flow

Going around an object: Part and rejoin smoothly

Is drag higher or lower with turbulent flow?

Higher

Why does flow matter?

How much energy the organism needs to use to move

Organisms might need better shapes to help them move through better 

What does an organism with streamline shape do to flow?

Laminar, allows streamlines to connect smoothly

You walking through air vs water: which has higher RE?

Air = high RE

water = low RE

Turtle swimming quickly vs. slowly: what has higher RE?

Quickly = high RE

Slowly = low RE

Fruit fly swimming through water slowly: high or low RE?

Low RE

Is high RE and low RE laminar or turbulent?

high RE = turbulent

low RE = laminar

What does high viscosity, low speed, and small objects mean in terms of RE? 

Low RE 

More fliud = more laminar

Reynolds Number

Dimensionless index that describes flow around an object

RE = (PU²)/(MU/L)

P = density

V = velocity

M = dynamic viscosity

L = characteristic length

Boundary layer

thin layer of fluid near a surfact where viscous effects are significant, causing the fluid’s velocity to vary from 0 at the surface to the free stream velocity further away

Implications of boundary layer for gas exchange

boudnary layer can act as a barrier to efficient gas exchange, particularly in low-flow environments

many benthic organisms actively circulate water past their respiratory surfaces, such as gills to inc gas exchange

awuatic insects may perform push-ups to inc water flow and oxygen uptake

Implication of boundary layer for food

effect on fluid dynamics is curical for how marine organisms access food, nutrients

thick boundary layer in slow-moving water can prevent suspended food particles from reaching org feeding structures (esp sessile org)

corals use cilia to create evortices that mix the boundary layers enhancing th egas exchange and nutruent delivery of their polyps 

Profile drag

drag of the fluid against the object (Friction)

Forces directly onto fish face

Induced drag

drag that is induced by the shape causing the water to move around it (resistance)

As speed inc what happens to profile and induced drag

Profile drag inc

Induced drag dec

How do fish handle induced drag?

As tuna is swimming, water must move around it (induced drag), faster the tuna swims it can outrun its own induced drag 

Low drag shape

Wide point is 1/3 back from the front

Do more circular fish have high or low drag?

Moves slow, wide point not 1/3 back from front, more drag

Bernoulli Principle

Look at slide for pic.

Fast speed- high pressure (top) = has to travel faster to reach end because it is a longer distance 

Slow-speed - high pressure (bottom)

Difference in speed causes pressure differences 

Why is an urchin stuck on bottom/how does it move?

Water moves above you fast, water doesn’t move below you = lift

Sea worm, how does it come out?

As water moves above bump where worm is (needs to move faster to get over bump), this pulls worm up

Does water have high or low viscosity and density?

High density and viscosity, very frictional against surface

End fin of a fish term

Caudal

Ancestral vs derived swimming patterns 

the more of a body the fish uses to swim, the more ancestral the fish is

the less of a body the fish uses to swim, the more derived the fish is

4 types of swimming

1) Anguilliform = eel

2) Subcarangiform = body + tail 

3) Carangiform = more caudal 

4) thunniform = tail (tuna), just caudal 

Boxfish = ancestral or derived?

Derived

Very stiff body, just uses its fins

Doesn’t move far

Siddon & Whitman

What is the goal of ecologists in general?

Investigate the pattern of why this is there and this isn’t

Siddon & Whitman

What resources are limited in the rocky intertidal? How about subtidal?

Space

What factors influence the patterns of what uses space on rocks?

Ability to withstand tides/waves, predators, can you find the food you need there

Siddon & Whitman

What general observation did they make about the distribution of organisms in the subtidal? 

Halfway Rock Gulf of Maine, US

On the exposed side from 1-3m deep, prey dominated (kelp, mussels). Predators (sea urchins, seastars) were absent from 1-3m and were restricted to areas below 3m deep. 

On the protected side the predators come up and eat in shallow waters

Siddon & Whitman

What hypotheses did they test?

Wanted to investigate the reason for the tidal zonation

1) The scarcity of sea urchins and seastars at shallow exposed areas is maintained by dislodgement

2) The hydrodynamic forces inhibit sea urchin and seastar movement in these areas

(Are the waves/hydradynamic forces too strong and literally sweeping predators away or making it impossible for them to get into those zones in the first place?)

Siddon & Whitman

Methods

1) Community structure = abundance of each org at sites 

2) Hydrodynamic site characteristics = velocity measurements 

3) Attachment strengths = max forces needed to dislodge sea urchins and seastars

4) Hydrodynamic force calculations = forces calculated for S, M, L of each species over range of water velocities and compared to attachment strengths to predict the probability of dislodgement 

5) Transplant exp = placed known amounts of urchins and seastars in both sites 

Siddon & Whitman

Main findings 

1) Routine water velocity (waves) were not strong enough to dislodge the urchins and seastars. You would need large velocity (not typical conditions) to dislodge 95% of them

2) transplant exp: urchins and seastars remained in shallow clearings with most water stress (where flow was strong)

3) water wasn’t strong enough to dislodge but it was enough to inhibit their movement

4) chronic low-level water flow inhibited their movement and foraging ability. Prey remain in those shallow high flow zones because predator can’t do anything

Elser

What general observations did they make?

Paradigms of N and P limitations in diff ecosystems:

N as primary limitins nutrient in terrestrial and marine

P as main limiting nutrient in lakes

Recent work has shown that N and P limitations are actually equal in lakes, which prompted this meta-analysis

Elser

What hypothesis did they test? 

Determine if patterns of nutrient limitation differ across systems. Does N and P have similar limitations in diff ecosystems because the mechanisms of autotrophs are the same or are there diff limitations becuase of processes controlling the amounts of N + P? 

Elser

What is nutrient limitation? 

When the growth and productivity of an organisms or ecosystem are restricted by a shortage of either N or P. 

These nutrients are essential for plant growth and various biochemical processes, and when their availability falls below the needs of the organism it limits their ability to thrive, leading to reduced primary production and ecosystem function.

Elser

Methods

Looked for studies that added one or both of the elements to ecosystem and recorded its effects 

Elser

Main findings

N mixed response, P similar

Marine tend to be more N limited

Lots of N, P variation in terrestrial

1) P limitation is strong everywhere: Despite vast differences in environment (lake, ocean..), the magnitude of primary producer response to P enrichment is similar across marine, freshwater, tropical ecosystems

2) In freshwater and terrestrial systems, N and P limitations are of equal importance (N wasn’t more limiting on land, P wasn’t more limiting in freshwater)

3) Simultaneous N + P enrichment = produces strongly positive synergistic responses in all 3 ennvironments, suggests that N + P supplies are much more closely balanced in ecosystems, needs both

Elser

Why study this? 

Understanding specific limiting factors in a habitat is key to designing effect and efficient solutions. can’t just add a lot of N and P becuase this might hurt ecosystem, cause algae blooms 

Phylum Porifera = SPONGES

Are sponges terrestrial? 

No. Only 2% are freshwater, rest ocean

5,000 species 

Phylum Porifera = SPONGES

Are they organized at the tissue level? 

No

May be collections of protozoans 

Phylum Porifera = SPONGES

Do they show primitive immune like response?

Yes, self-recognition

Phylum Porifera = SPONGES

Collar cells - choanocytes 

Act as a pump to bring water into the sponge 

Phylum Porifera = SPONGES

How do sponges grow so they can handle flow? 

Collar cells have flaggelar movement through sponge 

Phylum Porifera = SPONGES

Spicules 

Skeleton structures made of calcium carbonate (CaCO3) or silicon dioxide SiO2 

Fiber-like that makes their structure rigid and provide defense against predators

Useful in identification of type of sponge

Phylum Porifera = SPONGES

Reproduction

asexual budding or sexually (usually hermaphroditic with male and female cells scattered throughout the connective tissue) 

Can also be regenerated from broken pieces 

Phylum Cnidaria = Anemones, corals, sea whipes, hydroids, jellyfish

What are 2 defining characteristics? 

Formation of complex intracellular organelles called nematocysts

Planula larvae in life cycle

Phylum Cnidaria = Anemones, corals, sea whipes, hydroids, jellyfish

What are nematocysts?

Stingy parts = Used for gathering food or defense, competition (stinging neighbors)

Produced in special cells called cnidoblasts

Phylum Cnidaria = Anemones, corals, sea whipes, hydroids, jellyfish

Reproduction - what stages? 

Sessile stages and free swimming stage 

Which stage is dominant depends on the species (ex. corals have domanint sessile stage, jellyfish have dominant free swimming stage) 

Phylum Cnidaria = Anemones, corals, sea whipes, hydroids, jellyfish

What is important about the structure of anemone or coral polyp? 

Poop out and eat in same hole (only 1)

Why do some fish have ancestral traits while others have derived traits?

Evolution to fill diff niches ex. derived in coral

Why are shark fins heterocercal (asymmetric)?

biomechanics: more thrust generated from top to bottom, provides lift

What evidence is there that sponges are “ancestral” relative to cnidarians (coral)?

Sponges can do but coral can’t

1) Being able to deposit calcium carbonate

2) simple anatomy 

3) no tissue level organization (just cells doing things) 

Derived vs ancestral fish fins

Derived = pectoral and pelvic stacked on top of each other

Ancestral = both on bottom, pelvic more posterior and pectoral more anterior 

Phylum Annelida = worms

What is thier body structure? 

body is a tube within a tube

hydrostatic skeleton 

tough cuticle 

Phylum Annelida = worms

Class Polychaeta

Defining characteristic: Parapodia 

oar like, bristly arms 

differ from species to species and play an important role in identification 

Phylum Annelida = worms

Class Polychaeta

4 different lifestyles

crawling, pelagic, burrowing, tube-dwelling

Phylum Annelida = worms

Class Polychaeta

Reproduction

dioecious with gametes released into the coelom

many species reproduce en masse at the surface at night

moonlight and artifical light attract spawning masses

Phylum Arthropoda = crustaceans, insects, chelicerates

Where do chelicerates live? 

Primarily terrestrial 

Also horseshoe crabs and sea spiders 

Phylum Arthropoda = crustaceans, insects, chelicerates

Where do crustaceans live?

Marine and freshwater

Phylum Arthropoda = crustaceans, insects, chelicerates

Arthropod characteristics

Segmented bodies with some or all of the segments bearing jointed appendages 

chitinous exoskeleton, muscular connection inside the joints 

Phylum Arthropoda = crustaceans, insects, chelicerates

Pros of chitin vs. cons 

Pros = tough, stiff skeleton for protection 

Cons = hard to grow, have to malt (vulnerable until new skeleton forms) 

Phylum Arthropoda = crustaceans, insects, chelicerates

Arthropod segments: Two types of body regions 

Arthropod segments are grouped into body regions

Some have two regions, some have three

1) cephalothorax, abdomen

2) head, thorax, abdomen (lobster) 

Phylum Arthropoda = crustaceans, insects, chelicerates

Class Crustacea 

What barnacle anatomy? 

HIGHLY DERIVED 

Reduced head and 6 segmented thorax (six pairs of feather like appendages which are used for suspension feeding) 

Phylum Arthropoda = crustaceans, insects, chelicerates

Class Crustacea 

Barnacle reproduction 

Since they are sessile, they have long penis to search for female

Phylum Arthropoda = crustaceans, insects, chelicerates

Subclass copepoda

What is a defining characteristic? Where are they most abundant? 

No abdominal appendages 

Abundant in the plankton and benthic communities but due to small size escape notice 

Phylum Arthropoda = crustaceans, insects, chelicerates

Order Euphausiacea

What is a defining characteristic? 

Krill = Apart of arctice foodweb (small group)

Have 8 pairs of walking feet instead of 5 like most decapods

Phylum Arthropoda = crustaceans, insects, chelicerates

Order Isopoda 

What are defining characteristics?

Dorsoventrally compressed

Parasites → after particles that go by fish, not parasitic to the ifsh itself 

Phylum Arthropoda = crustaceans, insects, chelicerates

Order Decapoda

What is defining characteristics?

Large carapace that covers the thorax on the dorsal and sides

Segmentation is only visible from the ventral surface 

Phylum Arthropoda = crustaceans, insects, chelicerates

Shrimps

What are defining characteristics? 

Active and efficient swimmers, pleopods are well-developed for swimming

comercially important 

Phylum Bryozoa

What are they? Are they seaweed? What are their diff forms? 

Large and conspicuous colonies usually not recognized as animals 

incorrectly called seaweed 

primarly marine but some species are freshwater

Some may be soft and bushy, (Bugula) leafy and crisp, (Thalamoporella) or hard and crust like (Membranipora or Schizoporella)

Phylum Mollusca = clams, oysters, cuddlefish, stags, squids

What do they look like?

Wide variety of forms but all built around the same basic plan: bilateral symmetry, foot, shell, gut, gill, mantle cavity.

Phylum Mollusca = clams, oysters, cuddlefish, stags, squids

How do they see? 

Have either simple eyes or complex eyes (similar to human eye but evolved separately)

Sense organs, optic tentacles, simple eyes

Cephalopods have highly developed eyes (distinct images and possibly color) 

Phylum Mollusca = clams, oysters, cuddlefish, stags, squids

How do they reproduce? 

Those with indirect development have freeswimming trochophore larva (larval stage)

Phylum Mollusca = clams, oysters, cuddlefish, stags, squids

Different classes what organisms are in them?

chitons, whelks, cone shells, littorines, limpets, sea slugs, sea hares, mussels, scallops, nautilus

Phylum chordata = tunicates, lancelets, vertebrates (majority), invertebrates

Subphylum = urochordata (sea squirts/tunicates) 

What is a defining characteristic of this subphylum? 

Notochord and nerve cord are found ONLY in larval stage 

Most are filter feeders (Have two holes) 

Free swimming in larval stage but sessile in adult stage 

Mammalia - pinnipeds “feather-footed”

What percentage of marine mammals do they make up? 

What are the 3 categories and their percentages? 

34-36 species (25% of marine mammals) 

19 Phocids - 90% (seals) 

14-16 otariids (sea lions) 

1 odobenid (walrus) 

10%