Oceanography Essay Questions

Discuss why schooling behavior is adaptive to fishes.

Schooling behavior large groups of organisms swim in tightly spaced formation. Schooling confuses the predators and makes it harder to for a predator to successfully isolate a fish from the school for predation.

Tropical oceans are generally characterized by low net primary productivity. What are three environments that are exceptions to this and what factors contribute to their higher productivity?

1) Equatorial upwelling: Where trade winds drive westerly equatorial currents on either side of the equator, Ekman transport causes surface water to diverge toward higher latitudes. nutrient-rich water from depths of up to 200 meters. Equatorial upwelling is best developed in the eastern Pacific Ocean Coastal Upwelling Coral Reefs

How does the ocean's salinity vary with depth on different latitude location?

1) For the low-latitudes, a decrease in salinity with depth, higher salinity at the surface because surface water salinity is high due to evaporation and little to no precipitation and runoff. 2) For the high-latitudes, an increase in salinity with depth, lower salinity at the surface due to abundant precipitation and runoff and the melting of freshwater icebergs. In addition, cool temperatures limit the amount of evaporation that takes place.

What are the impacts of marine plastics in the ocean?

1) Ingestion, 2) Enganglement, 3) Habitat Damage, and 4) Non-native species etc.

Discuss how latitude and climatological processes affect seawater salinity.

1) Precipitation in the form of rain and snow decreases ocean salinity 2) river runoff and sea ice melting (such as icebergs) also add fresh water to the surface ocean decreasing salinity. 3) Evaporation increases the salinity of the surface ocean because water evaporates from the ocean increasing solute concentration. 4) When sea ice forms only water freezes in ice formation leaving the salt ions behind, increasing the sea surface salinity.

Describe the most common tail fin modifications and discuss the swimming styles associated with each fin modification.

1) Rounded fins are flexible and useful in accelerating and maneuvering at slow speeds. 2) Truncate fins and forked fins are found on faster fish; the fins are somewhat flexible for better propulsion but are also used for maneuvering. 3) Lunate fins are found on fast-cruising fish such as tuna, marlin, and swordfish; the fins are very rigid and useless for maneuverability but very efficient for propulsion. 4) Heterocercal fins are asymmetrical, with most of their mass and surface area in the upper lobe. Sharks have a heterocercal fin, which produces significant lift and is necessary because sharks have no swim bladder and tend to sink when they stop moving.

Discuss the adaptations used by marine organisms to prevent sinking.

1) Some animals have internal structures containing gas, which significantly reduce their average density. animals use either an internal, rigid gas container or a swim bladder to achieve neutral buoyancy, using the amount of air in their bodies to regulate their density, so they can remain at a particular depth without expending energy to do so. Larger animals often have the ability to swim, but if their bodies are denser than seawater, they must exert more energy to propel themselves through the water. 2) Floating animals range in size from microscopic shrimplike organisms to relatively large species, such as the familiar jellies. Microscopic forms of zooplankton usually have a hard shell called a test. Most types of microscopic zooplankton have adaptations to increase the surface area of their bodies (or shells) so they can remain in the sunlit surface waters near their food source. In addition, some organisms produce low-density fats or oils to stay afloat. Many larger forms, such as jellies, have soft, gelatinous bodies with little if any hard tissue, which reduces their density and allows them to stay afloat.

Explain the difference between a territorial sea and the Exclusive Economic Zone (EEZ).

1) Territorial seas: extend 12 miles from shore, owned by coastal nations, jurisdiction over the natural resources in their coastal oceans and seafloors 2) Exclusive Economic Zone (EEZ): extends jurisdiction to 200 nautical miles (the continental shelf). right to regulate fisheries, mineral rights, and pollution regulations within the EEZ.

What is the origin of the salt ions in seawater?

1) chemically weathered rock material carried by rivers, 2) volcanic gases, and 3) the remnants of marine organisms (shells, tests, calcareous body parts, for example). Other sources may include the atmosphere and biologic interactions.

List and briefly describe the four types of estuaries based upon origin and give an example of each.

1) coastal plain estuary: as sea level rises and floods existing river valleys. Also called drowned river valleys. Chesapeake Bay, Delaware Bay 2) fjord: floods a glaciated valley as sea level rises. Water-carved valleys have V-shaped profiles, but fjords are U-shaped valleys with steep walls. along the coasts of Alaska, Canada, New Zealand, Chile, and Norway. 3) bar-built estuary: separated from the open ocean by sand bars that are deposited parallel to the coast by wave action. common along the US Gulf Coast and East Coast, including Laguna Madre in Texas and Pamlico Sound in North Carolina. 4) tectonic estuary: forms when faulting or folding of rocks creates a restricted downdropped area into which the sea has flooded. California's San Francisco Bay

Why do algal blooms frequently occur during spring and fall in temperate oceans?

Algal growth is limited by nutrient availability (usually nitrogen and phosphorus) and light availability.

Why are upwelling zones generally more productive than coastal oceans?

Coastal oceans: shallow, higher nutrient inputs coming from terrestrial run-off. However, more turbidity in coastal waters, which limits the depth reached by solar radiation. Upwelling zone: upwelling brings cold, nutrient-rich waters up from depth to the surface. Colder water holds more oxygen than warmer waters. Upwelling zones provide nutrients which stimulate photosynthesis.

Compare and contrast warm and cold water marine species in terms of life span, body size, and relative abundance.

Cold water is denser and has a higher viscosity than warm water. 1) Floating organisms are physically smaller in warm waters than in colder waters. Small organisms expose more surface area per unit of body mass, which helps them maintain their position in the lower viscosity and density of warm seawater more easily. 2) Warm-water species often have ornate plumage to increase surface area. 3) Tropical organisms apparently grow faster, have a shorter life expectancy, and reproduce earlier and more frequently than those in colder water. 4) There are more species in warm waters, but the total biomass of plankton in colder, high-latitude waters greatly exceeds that of the warmer tropics. associated with the upwelling of nutrients, which in turn supports a vast biomass of phytoplankton.

What is coral bleaching? List the environmental conditions that contribute to the development of coral bleaching.

Coral bleaching describes the loss of color in corals that causes them to turn white, as if bleach has been poured on the reef. Corals are very temperature sensitive and coral bleaching is usually associated with elevated water temperatures that cause the coral's colorful symbiotic partner—zooxanthellae algae—to be expelled. Scientific studies suggest that reactive oxygen builds up in the coral's tissues and becomes toxic when temperatures are excessively warm, causing the coral to shed its normally beneficial algae.

Discuss the conditions that limit the distribution of corals worldwide.

Corals are found in areas worldwide where the annual minimum water temperature is generally above 18-20°C. In addition, corals generally need high light levels, low sediment levels, and a hard substrate for larval corals to settle and attach themselves to. In contrast, coastlines subjected to upwelling and/or extensive freshwater and sediment input from rivers generally do not support extensive coral reefs.

Discuss osmotic balance in freshwater and saltwater fishes.

Freshwater fish: their bodies have a higher solute concentration than their environment (hypertonic). not drink water, constantly excreting excess water by producing high volumes of dilute urine, the cells of freshwater fishes are also salt permeable. Marine fishes: their environments have higher salt (hypotonic), have a lower solute concentration in their body. constantly drinking water while excreting small volumes of highly concentrated urine.

List the major constituents dissolved in seawater in decreasing concentration.

Over 99% of the dissolved solids in seawater that exist in ionized form are chloride, sodium, sulfate, magnesium, calcium, and potassium.

Discuss the sources of information used by scientists to reconstruct climatic data prior to the era of modern climate records

Proxy for the climate record 1) Air bubbles trapped in polar continental ice sheets can be used to date the ice layer and estimate global temperature. 2) land-based ice, such as mountain glaciers, provides additional paleoclimate data. 3) Growth rings in ancient trees also yield information about past climate. 4) Ocean sediment analyses provide additional data about past climatic variation.

Briefly discuss the human-caused greenhouse gases in terms of their relative concentrations in the atmosphere and their relative contributions to global warming.

Several gases released by human enhancing greenhouse effect: carbon dioxide, methane, nitrous oxides, and CFCs. 1) carbon dioxide currently has the greatest concentration and the second greatest rate of increase (next to methane). Although carbon dioxide has a lower infrared absorption capability (on a per mole basis) compared to other greenhouse gases, it is the most abundant and thus has the greatest relative contribution to increasing the greenhouse effect. 2) Methane concentration is increasing the fastest of these gases and has 25 times the infrared radiation absorption of carbon dioxide, but is currently three orders of magnitude lower in concentration. 3) CFCs used as refrigerants and propellants have a disproportionately large absorptive effect, but are either stable or decreasing in concentration. 4) Nitrous oxides are thought to be about 5% of the relative contribution to the increasing greenhouse effect.

Define symbiosis and compare and contrast the different types of symbiotic relationships and give an example of each.

Symbiosis is a relationship in which organisms of two different species live together in close association. 1) Mutualism: both organisms benefit from the association. Ex: a cleaner wrasse and a grouper. The grouper has gill and mouth parasites removed by the cleaner wrasse preventing damage to vital parts of the body and the cleaner wrasse gets a meal without expending a lot of energy to forage or hunt for prey. 2) Commensalism: one organism benefits and the other is unaffected. Ex: a remora and a shark. The remora hitches a ride on the shark and gets the scraps left over from the shark's meal while the shark is unaffected by the remora's presence. 3) Parasitism: one organism benefits and the other species is harmed. Ex: gill isopod of fishes. The isopod gets a meal and protection from predators while the fish' s ability to exchange oxygen is compromised.

Coral reefs

Symbiotic microscopic algae living within the tissues of coral and other species allow coral reefs to be highly productive ecosystems. Coral reefs also tend to retain and recycle what little nutrients exist.

Describe the role of Intergovernmental Panel on Climate Change (IPCC).

The Intergovernmental Panel on Climate Change (IPCC) was formed in 1988 in a joint effort of the United Nations Environmental Programme and the World Meteorological Organization and began with more than 200 scientists studying human impact on the world's climate. Over 600 scientists in 40 countries contributed to the 2007 report. The IPCC has issued five reports on global climate change detailing growing scientific evidence that human activities are significantly impacting the world's climate.

What is the Kyoto Protocol? How has this accord impacted worldwide policies regarding greenhouse gas emissions?

This agreement, which is called the Kyoto Protocol (because it was created at an international conference held in 1997 in Kyoto, Japan), sets target reductions for each country. For example, 122 nations (representing 44% of the total worldwide carbon dioxide emissions) ratified the treaty, but the US government never formally agreed to the protocol, citing potential harm to the world economy. Further, the United States has lagged behind other countries in establishing emission reductions of greenhouse gases. But the United States is not alone: In 2011, Canada became the first country to withdraw from the Kyoto Protocol.

Briefly describe some of the differences between cetaceans of the Suborder Odontoceti (toothed whales) with those of the Suborder Mysticeti (baleen whales).

Toothed whales: having teeth for holding onto and orientating captured prey, have one external nasal opening or blowhole, mostly feed upon fishes and larger invertebrates such as squids, the ability to use sound appears to be better developed in the toothed whales, typically smaller than most of the baleen whales baleen whales: have two external nasal openings or blowholes. feed upon zooplankton and smaller fishes.

Explain the processes currently responsible for worldwide sea level rise. How will these changes in sea level affect coastal nations?

Two main factors contribute to the global rise in sea level: (1) thermal expansion of ocean water as it warms and (2) an increase in the amount of water in the ocean from the melting of ice on land. main contributors are: 1. The melting of the Antarctic and Greenland Ice Sheets; 2. The thermal expansion of ocean surface waters; 3. The melting of land glaciers and small ice caps; 4. The thermal expansion of deep-ocean waters

Explain why the majority of marine organisms are benthic.

Variability of habitat -> adaptation -> more species The ocean floor contains numerous benthic environments (such as rocky, sandy, muddy, flat, sloped, irregular, and mixed bottoms) that create different habitats to which organisms have adapted. On the other hand, most of the pelagic environment is quite uniform, no extreme environmental variability to which organisms need to be.

What is the difference between weather and climate? For example, if it rains in a particular location during the day, does that mean that the area has a wet climate? Explain.

Weather describes the conditions of the atmosphere at a given place and time, whereas climate is the long-term average of weather.

Coastal upwelling

Where the prevailing winds blow toward the equator and along western continental margins. nutrient-rich waters from depths of 200 to 900 meters. along the west coasts of continents

Briefly describe some of the changes that are already occurring in the oceans because of global warming.

global ocean surface temperatures have risen by about 0.6°C since 1970. Subsurface waters also are experiencing higher temperatures. Other changes include the melting of polar ice, changes in deep-ocean circulation patterns, rising sea level, and increases in ocean acidity, with corresponding changes in primary and secondary production.

What is longshore drift and how is it related to a longshore current?

net motion of water parallel to the beach, as a result of the zigzag movement of water due to run up (swash) and backwash the movement of sediment in a zigzag fashion caused by the longshore current.

Why is storm-water runoff or drain runoff a significant contributor to non-point source pollution?

point vs. non-point source pollution non-point source pollution - arrives at the ocean via runoff from storm drains. water (and any other material) that goes down a storm drain does not receive any treatment before being emptied into a river or directly into the ocean. On the contrary, sewage treatment plants receive enough waste to process without the additional runoff from storms, so it is important to monitor carefully what is disposed into storm drains.

Briefly describe differences between summertime and wintertime beaches and explain why these differences occur.

seasonal variations in wave activity. summertime beach - light wave activity, a wide, sandy berm, and an overall steep beach face at the expense of the longshore bar. wintertime - heavier, stronger wave activity, a narrow rocky berm, an overall flattened beach face, and a prominent longshore bar.