Marine Biology- Exam 2 Questions and Answers | Latest 2026 Update
Q: What are the three types of benthic deep sea sediments?
Answer:
-Siliceous ooze (10%): derived from diatoms and radiolarians Calcareous ooze
(50%): derived from coccolithophores, forams, and pteropods Red clay (40%): least
organic matter, high Mn and Fe content Food in the Benthic Deep Sea (small-scale
heterogeneity) -Surface appears homogenous But burrowing animals create food
patches Other animals are attracted Food in the Benthic Deep Sea (Whale Fall)
-Santa Catalina Basin, 1200m Discovered in 1987 during Alvin dive (at this point, all
flesh was gone) Revisited through 1995 Blue or Fin whale Living on Whale Bones:
Abundant microbial mats >40,000 invertebrates 6 species of bivalves 8 species of
gastropods 23 species of polychaetes 3 species of crustaceans 1 species of brittle star
Characteristics of Deep Sea Organisms -Few filter feeders (<7% of species) Few
herbivores and few strict carnivores Many deposit feeders
,Q: Many scavengers Hydrothermal Vent Communities -1977 Alvin dive by marine
geologists Searching for predicted "hydrothermal vents" Surprising discovery of
rich biological communities Tube worms, giant clams, mussels, crabs, snails,
polychaetes Chemosynthesis -No digestive tract Bacteria inhabit trophosome
("feeding body") Sulfide, oxygen, CO2, delivered by worms Carbohydrate
released by bacteria What is the H2S problem in polychaetes?
Answer:
Cytochrome c oxidase is poisoned by H2S as H2S outcompetes O2 for hemoglobin
binding, the solution is 3 types of hemoglobin that bind both H2S and O2 What is the
source of H2S? -Water mixes with vent fluids H2S and many other chemicals are
released from vents Clams, mussels, have symbiotic bacteria too Individual vents last
only a few days Colonization of Hydrothermal Vents -Vents are short-lived Vents are
separated by thousands of kilometers The habitat between vents is inhospitable How
do animals survive until they make it to a new vent? -Whale bones: they are rich in
lipids Anaerobic metabolism by bacteria produces H2S, bacteria are also food
, Q: Whale bones are stepping stones However, species overlap is minor,
lecithotrophic larvae may survive longer in cold water Cold Seep Communities
-1984 dive by petrologists Searching for oil seep sin Gulf of Mexico Another
discovery of rich biological communities Methane seeps from sediments,
bacteria live in gills of mussels where chemosynthesis is based Lamellibrachia
Tubeworm, contrasts with Riftia: long-lived, slow-growing (tested with dye in
chitin), also has H2S chemosynthesis Nekton Can actively swim in a body of
water What are the characteristics of Nekton?
Answer:
-Capable of active locomotion in water Most are vertebrates Seven classes of
vertebra NO marine amphibians Oldest vertebrate lineages 14,000 marine species
Temperatures to -1.9°C Life span to 100 years Size ranges 7mm to 12m What are the
three classes of fish? Agnatha, Chondrichthyes, Osteichthyes Class: Agnatha -TWO
groups: Hagfish and lampreys Cartilaginous skeleton
Q: What are the three types of benthic deep sea sediments?
Answer:
-Siliceous ooze (10%): derived from diatoms and radiolarians Calcareous ooze
(50%): derived from coccolithophores, forams, and pteropods Red clay (40%): least
organic matter, high Mn and Fe content Food in the Benthic Deep Sea (small-scale
heterogeneity) -Surface appears homogenous But burrowing animals create food
patches Other animals are attracted Food in the Benthic Deep Sea (Whale Fall)
-Santa Catalina Basin, 1200m Discovered in 1987 during Alvin dive (at this point, all
flesh was gone) Revisited through 1995 Blue or Fin whale Living on Whale Bones:
Abundant microbial mats >40,000 invertebrates 6 species of bivalves 8 species of
gastropods 23 species of polychaetes 3 species of crustaceans 1 species of brittle star
Characteristics of Deep Sea Organisms -Few filter feeders (<7% of species) Few
herbivores and few strict carnivores Many deposit feeders
,Q: Many scavengers Hydrothermal Vent Communities -1977 Alvin dive by marine
geologists Searching for predicted "hydrothermal vents" Surprising discovery of
rich biological communities Tube worms, giant clams, mussels, crabs, snails,
polychaetes Chemosynthesis -No digestive tract Bacteria inhabit trophosome
("feeding body") Sulfide, oxygen, CO2, delivered by worms Carbohydrate
released by bacteria What is the H2S problem in polychaetes?
Answer:
Cytochrome c oxidase is poisoned by H2S as H2S outcompetes O2 for hemoglobin
binding, the solution is 3 types of hemoglobin that bind both H2S and O2 What is the
source of H2S? -Water mixes with vent fluids H2S and many other chemicals are
released from vents Clams, mussels, have symbiotic bacteria too Individual vents last
only a few days Colonization of Hydrothermal Vents -Vents are short-lived Vents are
separated by thousands of kilometers The habitat between vents is inhospitable How
do animals survive until they make it to a new vent? -Whale bones: they are rich in
lipids Anaerobic metabolism by bacteria produces H2S, bacteria are also food
, Q: Whale bones are stepping stones However, species overlap is minor,
lecithotrophic larvae may survive longer in cold water Cold Seep Communities
-1984 dive by petrologists Searching for oil seep sin Gulf of Mexico Another
discovery of rich biological communities Methane seeps from sediments,
bacteria live in gills of mussels where chemosynthesis is based Lamellibrachia
Tubeworm, contrasts with Riftia: long-lived, slow-growing (tested with dye in
chitin), also has H2S chemosynthesis Nekton Can actively swim in a body of
water What are the characteristics of Nekton?
Answer:
-Capable of active locomotion in water Most are vertebrates Seven classes of
vertebra NO marine amphibians Oldest vertebrate lineages 14,000 marine species
Temperatures to -1.9°C Life span to 100 years Size ranges 7mm to 12m What are the
three classes of fish? Agnatha, Chondrichthyes, Osteichthyes Class: Agnatha -TWO
groups: Hagfish and lampreys Cartilaginous skeleton
