Survey of Oceanography
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30OceanicEnvironmentsandTheirEffectonSeaLifeb.pptxOceanic Environments and Their Effect on Sea Life
By: John Van Leer
Nov 8, 2019
Buoyancy is important a) Reduces need for structural support. b) Gas filled chambers such as swim bladders or gas sacks in kelp. c) Oils & Fats for energy storage and buoyancy. d) Polar bears have hollow hair, seabirds treat feathers with preen. e) Fat layer under the skin or buoyancy compensators and wet or dry suits for human divers.
Osmotic Processes regulate salt content compared to sea water. a) Fish Blood has half the salinity of seawater but fish must drink seawater, so they excretes salt excess across their gills. b) Sharks and Rays have about the same salinity as the ocean by maintaining high levels of urea to retain water. c) Sponges do not regulate. d) Sea birds excrete excess salts with salt glands on their beaks. e) Humans use reverse osmosis devices or a solar still to remove salt from drinking water.
Salinity in primitive organisms like a sea cucumber is not regulated. While higher organisms like bony fishes regulate their salinity to about half that of sea water. Water losses by osmosis through the skin is offset by excretion through gills and urine.
Temperature changes change metabolism. a) Seabirds, tunas, great white sharks & mammals temperature regulate, which is easier in large sizes. This gives them a competitive advantage as they can swim faster. b) People use fat layers, wet or dry suits or suits with circulating hot water to maintain body temperatures.
Bottom Types include: a)Mud b) Silt c) Sand d) Gravel d) Boulder e) Bare Rock f) or even Permafrost.
Pressure - No Problem if no gas bubbles. a) Humans must be protected from pressure or breath air at the same pressure, as the depth where they are located. b) Problems arise with gas solubility in different tissues like muscle, bone or fat. So, human divers can get the bends or an embolism, by decompressing too rapidly.
Common breathing gasses contain Oxygen, Nitrogen and Carbon Dioxide. If diving below 100 feet, Nitrogen may become narcotic, so deeper diving may be done with Heliox a mixture of Helium and Oxygen. In 1000 foot depths, a diver my require a mixture of Hydrogen and Oxygen.
Buoyancy contributes to the support of marine plants and animals
Many species of Benthic Algae have trapped gas bubbles built into their structure, to lift their fronds toward the sea surface, for more efficient use of solar energy.
Kelp forests in water depths of a hundred feet or more are common along the West Coast of the USA. With a warming ocean, kelp forest may need help pumping neutrients upward through the thermocline. (see DRAWDOWN)
Primary productivity measures the amount of carbon that is fix by plants.
Zones of life are constrained by tides, light and depth.
Rocky Shore lines have different zones depending on the tide level. How long can marine organisms be exposed to air? On the bright side they may escape predation.
Light penetration is limited to the upper few hundred meters, even in the clearest tropical ocean waters. In turbid waters, the depth of penetration is much less, so photosynthesis is more limited.
Nutrients like nitrogen and phosphorous, or minor nutrients are taken up by phytoplankton in the near surface layer of the ocean. Dying organisms sink taking their nutrients with them. This is often called the nutrient pump or the carbon pump.
Plants have respiration which takes up oxygen when there is not enough light.
High primary production of phytoplankton may be reduced by grazing of herbivores, leaving a small standing crop.
Only a small part of life in the ocean is visible to the naked eye, while the majority can’t even be seen with an optical microscope.
The biota are divided into producers (Autotrophs) and consumers (Heterotrophs).
Camouflage is used to hide prey from predator and visa versa. Note: The Countershading which war planes have copied the salmon looks silver from below but matches the darker bottom when viewed from above.
Pigment cells in a fishes skin can be controlled in some species like a flounder.
The ratio of surface area to volume determines the drag force on a sinking or buoyant cell. So, larger cells sink or rise much faster than small ones
Currents can present problems such as the transport small creatures, like phytoplankton, who must go with flow, they might be subducted along a convergent front, and involuntarily moved out of the photic zone.
Phytoplankton are usually small to microscopic, so that mixed layer turbulence will keep them suspended in the photic zone for a long time.
Larval forms of familiar organism like barnacles, may not resemble the adult form.
Identifying color schemes, like the Sargent Major allow self identification. Like zebra stripes, they could be disorienting to a predator, confronting a dense school.
Star fish can reproduce from a single arm, making them very hard to kill.
Flat fish, like this little peacock flounder, blend with the bottom and can even cover themselves with sand for a perfect match. Note: Both eyes are on the upside.
Clown fish are immune to the stinging cells of the anemone and hide there for protection and food.
Taxonomic Categories of a few Marine Organisms
Arctic Productivity occurs in a shorter period than in the Subtropics.
Phytoplankton and Zooplankton biomass vary with stability and solar input.
Solar energy drives the whole system. Note: The Zooplankton lag behind the Phytoplankton biomass.
Bongo nets can fish with two different mesh sizes at the same time. Note: The small current meters in the mouth of each net to estimate the number of cubic meters of water filtered by each net.
Seasonal and geographic variability of primary productivity as seen in surface pigment concentration observed by earth satellite.
Although upwelling zones are only about 1% of the ocean area they account for about half the fish caught.
Comparison of Gross Primary Productivity on Land and in the Ocean.
The small things in the ocean greatly outnumber the large things, which depend on them. Microbial forms would be correspondingly more abundant.
Oceanic Food Production
Dissolved Organic Matter is a catchall phrase for the vast store of organic matter in the ocean, includes naked DNA sloughed off by passing fish and other creatures.
Trophic levels in the Antarctic is much simpler than in a tropical ocean setting.
The amount of biomass in the ocean varies with latitude and season.
Productivity varies with latitude.
Harmful Algal Blooms, like Ciguatera poisoning occur in specific locations.
Parasitic Shellfish Poisoning Locations
The Phosphorous Cycle on land an in the sea has become more important with Climate change concerns.
Nitrogen Cycle even involves Lightning.
