Learn: EMES 442 Fall 2026 Term Exam 1

Azoic theory

Edward Forbes proposed that no life existed below 300 fathoms (~1,800 ft). Michael Sars later disproved the theory by finding organisms below that depth.

H.M.S. Challenger

expedition that provided first global view of marine biology, led by Wyville Thomson and John Murray from 1872-1876. Explored all seas but the Arctic

Bathybius theory

The idea that all life arose from a primordial slime (disproved by Challenger expedition)

Neuston

organisms associated with the sea surface (including microorganisms)

Plankton

organisms that live suspended in the water (may have some ability to move but cannot counteract ocean currents or turbulence)

Epifaunal

organisms living on the seabed surface

Benthos

animals and plants associated with the seafloor

Infaunal

organisms that can burrow within the soft seabed

Semi-infaunal

organisms living partially buried within the sediment but partially projecting into the water column

Primary producer

an organism capable of using the energy derived from light or a chemical substance to make energy-rich organic compounds

Primary consumer

an organism that consumes a primary producer

Top down effect

occurs when predators consume their prey

Bottom up effect

changes in lower trophic levels exert strong effects on ecosystem

nonconsumptive effect

the presence of a predator causes prey species to retreat to shelter. This reaction reduces predation at the next level down in the food chain

Primary production

the synthesis of organic compounds from CO2, principally occurring through photosynthesis

photosynthesis

process by which an organisms captures the light energy from the sun and uses it to make energy-rich organic matter (CO2+H2O-->CH2O+O2)

respiration

the process by which an organisms breaks down organic matter to release chemical energy such as ATP, NADH (CH2O+O2-->CO2+H2O)

compensation depth

the depth at which the light intensity is sufficient for a cell to have equal photosynthesis and respiration

critical depth

the depth at which the integrated rates of photosynthesis and respiration are equal

What is an HNLC region and why can it occur?

High Nutrient, Low Chlorophyll. Major nutrients may be abundant, while a trace nutrient, especially iron (Fe), limits phytoplankton growth. The current lecture specifically identifies Fe limitation.

GPP

gross primary production, the total carbon fixed

NPP

net primary production, amount of C made into new phytoplankton biomass and available to primary consumers (GPP-respiration)

Oligotrophic

low nutrients, low rates of primary production

Eutrophic

high nutrients, high rates of primary production

Mixing depth

The depth above which water is thoroughly mixed by wind. A phytoplankton bloom can develop when the mixing depth is shallower than the critical depth.

harmful algal blooms (HABs)

rapid growth of phytoplankton/algae where some species produce toxins. Exposure and accumulation of such toxins have effects on marine food chains and human health

Ciguatera

Food poisoning caused by toxic dinoflagellates (genus: Gamierdiscus) that produce ciguatoxin that bio-accumulates in carnivorous fish

the microbial loop

the process by which dissolved organic matter is returned to higher trophic levels through incorporation into bacterial biomass

bacteriophage

a virus that infects a bacterial host

viral shunt

the transfer of energy and nutrients from living organisms into the dissolved phase through the process of viral lysis

How does rising atmospheric CO2 affect the ocean?

Rising atmospheric CO2 contributes to ocean warming and thermal anomalies. When CO2 dissolves in seawater, hydrogen ion concentration increases, pH decreases, and carbonate availability decreases. This can make calcium carbonate formation more difficult for marine calcifiers.

upwelling

upward movement of cold, nutrient rich water from the deep to surface

What does the Keeling Curve show?

The Keeling Curve shows the long term rise in atmospheric CO2 together with seasonal fluctuations. The class material showed approximately 428 ppm in August 2026.

Zooplankton

Heterotrophic plankton, including protists and animals, that drift with currents or cannot consistently swim against them. They connect primary producers and microbes with higher trophic levels.

Holoplankton

organisms that spend all their life in the water column and not on/in the seabed

Meroplankton

organisms that spend part of their time in the water column but also spend time in the benthos

Ichthyoplankton

the eggs and larvae of fish

Burgess Shale fossils

important fossil site that represents an early snapshot of the complexity of evolving life systems that evolved from simpler, pre-Cambrian forms. These life forms were buried in an underwater avalanche of fine mud that preserved detailed structures

What major developments helped shape marine biology?

Aristotle contributed early observations of marine organisms. Linnaeus developed systematic classification. Cuvier advanced comparative anatomy. Edward Forbes proposed the Azoic Theory. Later exploration and technology greatly expanded marine biology.

environmental sex determination (ESD)

Sex is determined after fertilization by environmental conditions. In sea turtles, warmer incubation generally produces more females and cooler incubation more males

How is the global ocean conveyor belt initiated?

In polar regions, seawater becomes cold and salty. This increases its density and causes it to sink. Surface water moves in to replace the sinking water, helping drive deep ocean circulation.

What is chemosynthesis at hydrothermal vents and cold seeps?

Chemosynthesis is the production of organic matter using energy from chemical substances rather than sunlight. Chemosynthetic microbes form the base of food webs at hydrothermal vents and cold seeps.

What are the three key components of marine biology?

Functional biology, ecology, and biodiversity. Functional biology examines how organisms function. Ecology examines interactions among organisms and their environment. Biodiversity examines the variety of life.

intertidal zone

ranges of depths between highest/lowest extent of the tides

subtidal zone

entire remainder of the sea from low water tidemark to greatest depth of the ocean

neritic zone

(aka continental shelf) includes all seafloor and open water habitats between the high water mark and the shelf edge

How is marine primary production measured?

Carbon 14 method, light dark bottle method, and satellite observations. Carbon 14 measures carbon fixation. Light dark bottles use changes in oxygen. Satellites estimate productivity using ocean color and chlorophyll related observations.

What factors affect marine primary production?

marine primary production?Light, nutrients, temperature, mixing and circulation, water clarity, phytoplankton community, and grazing.

examples and general characteristics of photosynthetic marine organisms

diatoms, dinoflagellates, cyanobacteria, seaweeds, sea grasses (be able to recognize a picture). All contain chlorophyll a

abundance of bacteria/viruses per 1 L seawater

1 billion bacterial cells per liter, 10 billion viruses per liter

How are NPP and GPP calculated using light dark bottles?

NPP equals the change in oxygen in the light bottle. GPP equals the change in the light bottle minus the change in the dark bottle. The dark bottle represents respiration.

How does primary production vary with environmental conditions?

Tropical waters are commonly limited by nutrients. Temperate waters vary seasonally with light and nutrients. Polar waters are strongly affected by limited light. Mixing also affects whether phytoplankton remain in the illuminated zone.

planktotrophic larval dispersal

Larvae feed while in the plankton. They have small and numerous eggs, spend about 10 to 40 days in the plankton, and generally have greater dispersal.

lecithotrophic larval dispersal

Larvae rely on yolk reserves rather than feeding in the plankton. They have larger and fewer eggs, spend about 0 to 5 days in the plankton, and generally have poorer dispersal.

Distinguishing characteristics of Porifera

Simple sessile multicellular animals made of loosely aggregated specialized cells. They lack true tissues and organs and generally filter feed. They are supported by spicules and or spongin.

What is a cnidocyte and nematocyst?

A cnidocyte is a specialized stinging cell that contains a nematocyst. When stimulated, the nematocyst rapidly discharges a thread used for prey capture or defense.

distinguishing characteristics of plathelminthes

Bilaterally symmetrical, flat, unsegmented worms.

What distinguishes Ctenophora?

Ctenophores are comb jellies. They possess eight rows of cilia called combs that are used for locomotion.

Distinguishing characteristics of Nematoda

Unsegmented cylindrical roundworms with a pseudocoelom.

Distinguishing characteristics of Annelida

Worms characterized by segmented bodies. Marine examples include polychaetes.

Distinguishing characteristics of Mollusca

A diverse group including snails, slugs, bivalves, squid, and octopuses. Many possess a mantle and specialized feeding structures.

Distinguishing characteristics of Arthropoda

Characterized by an exoskeleton, segmented body, and jointed appendages. Marine examples include crustaceans and horseshoe crabs.

echinodermata distinguishing characteristics

calcareus endoskeleton, locomotion by water vascular system

chordata distinguishing characteristics

Chordates possess a notochord at some stage of development. Marine invertebrate chordates include tunicates and sea squirts.

basic biology of sponges

1. choanocytes pump water through ostia

2. food particles are transferred to the mesohyl where digestion takes place by archaeocyte cells

3. filtered water is expelled through the oscula

hydrozoa distinguishing characteristics

generally colonial with distinct polyps for feeding and reproduction

scyphozoa distinguishing characteristics

the "common jellyfish" that alternates between polyp and medusa forms

anthozoa distinguishing characteristics

lacks a medusa stage

sea snake characteristics

found in indo-west pacific, ectotherms, prey upon fish, air breathers, must drink freshwater, excrete excess salt via salt glands, not native to Atlantic Ocean

marine iguana characteristics

The Galapagos marine iguana is the only marine lizard. It is ectothermic, mainly feeds on submerged algae, and warms its body in the sun before diving.

why did marine iguanas shrink?

El Nino events caused green algae to die off, replaced with hard to digest brown algae. Iguana who shrank as adaptation to food shortage lived longer

What are the five orders of true seabirds?

What are the five orders of true seabirds?Procellariiformes are tubenose birds. Pelecaniformes are pelicans. Suliformes are boobies and relatives. Charadriiformes are gulls, terns, and relatives. Sphenisciformes are penguins.

What are major nesting and reproductive characteristics of seabirds?

Many seabirds nest in colonies. They generally have small clutch sizes, long incubation periods, long chick-rearing periods, and extensive parental care.

How do seabirds maintain salt and water balance?

Nasal salt glands remove excess salt. Seabirds also excrete uric acid rather than urea, which reduces water loss.

How does olfaction help seabirds forage?

Many seabirds have well developed olfactory bulbs and use odors to locate productive feeding areas. Some can detect compounds associated with plankton activity and feeding areas.

What are three major feeding strategies of seabirds?

What are three major feeding strategies of seabirds?Aerial feeding, diving and swimming, and kleptoparasitism.

What methods can scientists use to study marine microbes?

What methods can scientists use to study marine microbes?Molecular techniques, microscopy, and culturing approaches.

What cues can marine larvae use when selecting a settlement site?

Light, salinity, depth, pressure, current speed, adults present, chemical cues, substrate quality, and bacteria.

What are some major groups of zooplankton?

Ciliates, foraminiferans, radiolarians, jellyfish, siphonophores, comb jellies, arrow worms, polychaetes, pteropods, copepods, krill, salps, and larvaceans.

Why are there no truly marine amphibians?

Amphibians have highly permeable skin. In seawater, this would be a poor barrier and could cause dehydration and ionic imbalance.

examples of adaptations in marine mammals

streamlined body for efficient swimming, rapid breathing to extract oxygen, nostrils on top of head, more red blood cells (and hemoglobin per cell), bradycardia, restricted blood flow to non-essential tissues, avoiding "the bends", echolocation, delayed implantation, migration

oxygen conservation methods of marine mammals

preferentially gliding over swimming when diving

pycnocline

rapid change in density over a short vertical distance

thermocline

rapid change in temperature over a short vertical distance

nekton

larger organisms that swim in the watercolumn and can move against a current or turbulence

epipelagic zone

upper 200 meters of water

mesopelagic zone

200-1000 meters

bathypelagic zone

1000-4000 meters

abyssopelagic zone

4000-6000 meters

hadal zone

>6000 meters (seabeds and in waters of trenches)

protists

single-celled zooplankton, usually feed on bacteria and consumed by larger zooplankton

epithelial cells (sponges)

form protective barriers by lining body surfaces and internal cavities, performing functions like secretion, absorption, and sensory perception

What are spicules and spongin?

Spicules are sharp mineral or protein structures that provide support and can deter predators. Spongin is a flexible fibrous protein that provides support and can hold spicules together

Approximately how much of Earth is covered by ocean?

About 71 percent of Earth's surface is covered by ocean and about 29 percent is land.

cnidaria phylum, general features

- Have "true tissue" organization

- Two tissue layers : ectoderm and endoderm, held by mesoglea

- Often alternate between polyp and or medusa stages

- Stinging cells (nematocysts) are commonly found on tentacles

- 3 main classes: Hydrozoa, Scyphozoa, Anthozoa

characteristics of a true seabird

marine dependency, life cycle at sea, waterproof feathers, salt glands, specialized feet, diving/plunge-diving, long-distance flight

kleptoparasitism

- Feed on food or eggs of other birds

- Grabbing food, pulling feathers, and forced regurgitation

- Opportunistic: rob visible food, attack own species

- Specialized: give calls to startle the bird into dropping food

- Frigate bird, skua, gull, tern

characteristics of sea turtles

- Vertebrates and Ectothermic

- All species but the Leatherback have the backbone and ribs fused to shell

- Air-breathing (lungs)

- Possess salt glands which help excrete the

salt taken in when they drink seawater

(located near the eyes)

- oviparous

- prefer shallower waters

characteristics of mesozoic marine reptiles

- Do not share a common body form

- Most have some degree of streamlining for hydrodynamics and modification of appendages into joint-stiffened paddles or flippers

- Some were small, but most were large/gigantic

- Most were predators that fed on invertebrate and vertebrate prey (small to large)

- Few herbivores