Reading Material

Question 1

Martin et al (1990)

Primary production limits

Answer 1

Offshore Drake Passage waters (Antarctic) have dissolved iron levels so low that phytoplankton were able to use less than 10% of the major nutrients available to them.

Question 2

Harrison and Cota (1991)

Primary production limits

Answer 2

Nutrient concentrations in Arctic surface waters are considerable lower in contrast to the Antarctic.
Productivity and algal biomass correlate positively with nutrient availability.
Enrichment bioassays showed that nitrogen limits algal ice biomass in estuarine waters.

Question 3

Tovar-Sanchez et al (2007)

Secondary production

Answer 3

Presence of krill has a significant impact on ambient iron concentrations.
Iron release rate was shown to reflect food availability.
Results show that krill plays a major role in iron cycling in the Southern Ocean, and influences iron residence time in the upper water column.

Question 4

Falk-Peterson et al (2009)

Secondary production

Answer 4

Canals species convert low-energy carbs in ice algae and phytoplankton into high-energy wax esters.
These are transferred through the food chain, and act as a major source of energy for fish, birds and marine mammals.

Question 5

Rudels et al (1990)

Stratification

Answer 5

Influences on stratification in the Arctic are dominated by freezing and melting.
Sea ice moves relative to water, and a low-density surface layer is created as ice drifts over and melts on warmer waters.
Nutrients are added by inflows of Pacific waters and rivers.
As there is no mixing, nutrients are trapped.

Question 6

Lotterhos (2010)

Broadcast spawning

Answer 6

One strategy is called spermcasting, where the male releases sperm into the surrounding water.
Females retain their eggs on the surface.
Females are able to integrate sperm concentrations in the water over the life of the egg.
This method has high fertilisation rates.

Adult polychaete may increase viscosity of spawned material when turbulence is high to reduce the rapid dilution of gametes.

Question 7

Heath (1977)

Simultaneous hermaphroditism

Answer 7

Simultaneous hermaphroditism gives an advantage to organisms that are widespread or sluggish, as they have a low frequency of reproductive contacts.

It is not seen in more species because maintaining two reproductive systems is energetically costly, and there is a reduced number of offspring due to accidental self-fertilisation.

Question 8

Chimitova (2011)

Epitoky

Answer 8

The presence of epitokous males of S. Stepposa is linked to population density.
Epitzoky could give an advantage in competition between males when the population density is high.

Question 9

Hess (1993)

Parental care

Answer 9

Caribbean jawfish show male mouth brooding.

This limits male mating success, as polygyny is constrained or prohibited.

Question 10

Towle (1997)

Adaptation in estuaries

Answer 10

Carcinus maenas has high levels of Na+/H+ antiporter protein and mRNA, which respond to salinity reduction.

Question 11

Osuya and Feeney (1978)

Adaptation in polar ecosystems

Answer 11

Antifreeze glycoproteins were isolated from the blood of Arctic polar cod, and compared to the antifreeze glycoprotein of the Antarctic bald rockcod.
Composition of the active region was close to identical.
The proteins had identical fundamental structures.

Question 12

Sanders et al (1991)

Rocky shores

Answer 12

Intertidal limpits from the genus Lottia have heat shock proteins that respond to protein damage caused by temperature.
Found to be important for limpets in the upper end of their physiological temperature range at higher tidal heights.

Question 13

Gosselin et al (1990)
Primary production (polar vs. tropical)

Answer 13

In the Canadian Arctic, ice-algal growth is found to be light-limited at the beginning season, followed by silicon limitation.

Question 14

Pennington et al (2006)
Primary production (polar vs. tropical)

Answer 14

Primary production in the tropics is determined by the supply of macronutrients below the thermocline.
Biological production is highest where the thermocline is shallow and intersects the lighted euphotic zone.
Primary production is largely increased above oligotrophic subtropical gyres, with enhanced rates of nutrient supply.

Question 15

Doolan 2010

Age (polar vs. tropical)

Answer 15

450 million year old reef, in Isle la Motte, Vermont, is known for preservation and size of its fauna.

Question 16

Vacchi et al (2012)

Diverse habitat types/nursery grounds (tropical vs. polar)

Answer 16

Antarctic silverfish is a dominant pelagic fish in continental shelf waters in high Antarctic regions.
Uses ice as a nursery ground, trapping eggs in ice platelets under sea ice during spring.

Question 17

Robertson and Duke (1987)

Diverse habitat types/nursery grounds (tropical vs. polar)

Answer 17

Post-larval and juvenile fish are 4-10x more abundant in mangroves compared to other near-shore tropical habitats.

Question 18

Sarimento et al (1998)

Oxygen and CO2

Answer 18

• Increased oceanic stratification due to global warming
• Increased rainfall, leading to surface freshening
  Reduces the downward flux of oceanic uptake of anthropogenic CO2.

Question 19

Whitmarsh et al (2015)

Climate

Answer 19

Over last 16 years, there has been a slowing/reduction in long-term increase of oceanic surface temperatures.
Changes in Atlantic ocean circulation are thought to have reduced heat uptake.

Question 20

Rayman (2000)

Diet

Answer 20

Selenium is an essential trace mineral found in fish, such as rockfish, tuna, herring, and salmon.
Acts as an antioxidant, and catalyst for active thyroid hormone.
Counteracts the development of virulence and inhibits the progression of HIV into AIDs.

Question 21

Ling et al (2009)

Overfishing

Answer 21

In Tamzanian kelp beds, overfishing of predatory fish and removal of large predatory lobsters reduced the resilience of kelp beds against invasive sea urchins.
This increases the risk of a catastrophic shift to widespread sea urchin barrens.

Question 22

Mullon et al (2005)

Fisheries collapse

Answer 22

Number of fishery collapses are stable throughout time since the 1950s, indicating no improvement in the overall management of fisheries.

Question 23

Edinger et al (1998)

Environmental issues in fisheries and aquaculture

Answer 23

Anchor-damaged reefs from fishing experienced 50% less biodiversity than undamaged reefs in the same region.

Question 24

Marine Conservation Society (2017)

Environmental issues in fisheries and aquaculture

Answer 24

Hybrid fish (from genetic dilution of wild stock) are likely to have no genetic adaptations to survive in the wild.
This can lead to a decline of future population numbers and resilience.

Question 25

Rees et al (1998)

Light (deep sea)

Answer 25

Coelenterazine is a luciferin with antioxidative properties.

Its original function is thought to be the detoxification of deleterious oxygen derivatives.

When colonising deeper ocean, exposure to oxidative stress is considerably reduced, due to reduced light irradiance and lower oxygen levels.
This likely lead to a functional shift to its light-emitting function.

Question 26

Gibbs and Somero (1989)

Pressure

Answer 26

Inhibition of maximal velocity of Na+/K+-ATPase increases at high pressures.

Na+/K+-ATPases of deep sea fish were less inhibited by pressure than shallow-living species.

Question 27

Higgs et al (2014)

Food (deep sea)

Answer 27

Food falls are where the carcasses of large pelagic vertebrates sink to the sea floor.

Looked at the effects of food falls from whale sharks and mobulid rays.
Found that carcasses supported moderate communities of Zoarcidae scavenging fish, up to 50 individuals per carcass.
Estimated that carcasses provide long-term food supply, from weeks to months, for deep sea organisms.