Reading Material Flashcards
(27 cards)
Martin et al (1990)
Primary production limits
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.
Harrison and Cota (1991)
Primary production limits
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.
Tovar-Sanchez et al (2007)
Secondary production
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.
Falk-Peterson et al (2009)
Secondary production
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.
Rudels et al (1990)
Stratification
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.
Lotterhos (2010)
Broadcast spawning
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.
Heath (1977)
Simultaneous hermaphroditism
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.
Chimitova (2011)
Epitoky
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.
Hess (1993)
Parental care
Caribbean jawfish show male mouth brooding.
This limits male mating success, as polygyny is constrained or prohibited.
Towle (1997)
Adaptation in estuaries
Carcinus maenas has high levels of Na+/H+ antiporter protein and mRNA, which respond to salinity reduction.
Osuya and Feeney (1978)
Adaptation in polar ecosystems
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.
Sanders et al (1991)
Rocky shores
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.
Gosselin et al (1990) Primary production (polar vs. tropical)
In the Canadian Arctic, ice-algal growth is found to be light-limited at the beginning season, followed by silicon limitation.
Pennington et al (2006) Primary production (polar vs. tropical)
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.
Doolan 2010
Age (polar vs. tropical)
450 million year old reef, in Isle la Motte, Vermont, is known for preservation and size of its fauna.
Vacchi et al (2012)
Diverse habitat types/nursery grounds (tropical vs. polar)
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.
Robertson and Duke (1987)
Diverse habitat types/nursery grounds (tropical vs. polar)
Post-larval and juvenile fish are 4-10x more abundant in mangroves compared to other near-shore tropical habitats.
Sarimento et al (1998)
Oxygen and CO2
- Increased oceanic stratification due to global warming
- Increased rainfall, leading to surface freshening
Reduces the downward flux of oceanic uptake of anthropogenic CO2.
Whitmarsh et al (2015)
Climate
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.
Rayman (2000)
Diet
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.
Ling et al (2009)
Overfishing
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.
Mullon et al (2005)
Fisheries collapse
Number of fishery collapses are stable throughout time since the 1950s, indicating no improvement in the overall management of fisheries.
Edinger et al (1998)
Environmental issues in fisheries and aquaculture
Anchor-damaged reefs from fishing experienced 50% less biodiversity than undamaged reefs in the same region.
Marine Conservation Society (2017)
Environmental issues in fisheries and aquaculture
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.
