OCE 3008 (Fi) Ch.13 - Biological Productivity and Energy Transfer

Photosynthesis

Biological process in which an organism, like plants, algae, and bacteria will convert solar radiation from sunlight into chemical energy into the form of sugar.

Primary Producers

Plants, algae, and bacteria are ____________ ___________________. Phytoplankton for example, are responsible for the majority of photosynthesis in the ocean.

Biomass (2x)

________________ is the total mass of all organisms. 99.9% of the oceans ________________ relies directly or indirectly on photosynthesis for food.

Plankton Net

This is a very fine piece of mesh that scientists tow behind a research vessel and use to collect plankton samples.

It allows scientists to directly measure primary productivity.

bottle

Another way aside from measuring primary productivity in the ocean is through the measure of radioactive carbon in seawater. Scientists use ______________ experiments to quantify rates of photosynthesis and respiration.

SeaWiFS (Sea-viewing Wide Field of View Sensor)

This is a device in which scientists measure primary productivity in the ocean.

This device is a satellite that uses a sensor to collect data on the ocean color.

This device was able to quantify data since phytoplankton would use a green pigment known as chlorophyll during photosynthesis.

This device was launched in 1997 and ended in 2010.

MODIS (Moderate Resolution Imaging Spectroradiometer)

This is a satellite sensor used by NASA still today that measures a wide range of Earth's properties like vegetation, land cover, and the ocean's primary productivity.

It does this by measuring 36 spectral frequencies through ocean fluorescence. It even collects data on phytoplankton productivity.

Nutrient Availability

Solar Radiation (Sunlight)

What are the two major factors that affect primary productivity in the ocean?:

Nutrients (Nutrient Availability)

This is the most important factor affecting distribution of marine life.

This factor is mostly the highest in productivity along the continental margins, but is generally limited in the pelagic region of the ocean.

Redfield Ratio

This is a number that describes the relative proportion of nutrients (specifically Carbon : Nitrogen : Phosphorus) when they are not limiting.

Usually on average this number is 106:16:1 (C:N:P).

This number is a standard proportion used to understand nutrient and cycling and productivity in many marine ecosystems.

Eutrophication

This is the process in which a body of water becomes overly enriched with nutrients, like nitrogen or phosphorus.

Such enrichment can lead to excessive growth of algae and aquatic plants which can then disrupt the ecosystem by depleting oxygen and possibly harming aquatic life.

False (It limits biological productivity)

(T or F): The lack of nutrients can help with biological productivity.

Solar Radiation (Sunlight)

One of the major factors affecting primary productivity.

This factor is available in the uppermost surface of the ocean all the way to the shallow part of the seafloor.

Compensation Depth

This is a certain depth in the ocean where the net photosynthesis gain becomes zero.

This is because at this depth, the losses in respiration equals the gains from photosynthesis in the ocean.

Ocean Winds

Ocean Stratification (Layers of the ocean)

Primary Productivity (In the ocean)

Solar energy has a major impact on:

visible light

Most solar energy is in the _______________ ______________ portion of the electromagnetic spectrum.

True

(T or F): The ocean selectively absorbs longer-wavelength colors first. With that being said, red wavelengths are the first absorbed.

False (Blue wavelengths penetrate the deepest, so they are in fact the last to be absorbed.

(T or F): Blue wavelengths are the first to be absorbed by the ocean.

Secchi Disk

This is a flat, white disk that can be lowered into the water by a rope until it is barely visible.

It measures the clarity of the water.

Oligotrophic

This refers to a body of water that is relatively low in productivity.

An example of this would be the open ocean. Its color is dark blue due to limited light from being scattered through water molecules.

Upwelling

This is the flow of deep water to the surface due to offshore Ekman transport.

Sites with this flow of water are high in productivity.

Anthophyta

These are a type of photosynthetic marine organism that is only found in shallow coastal waters.

It is a flowering plant in the plant kingdom that require sunlight. They are primarily seagrasses and mangroves.

They also act as important sources of food, habitat, and protection for nearshore animals.

Macroscopic Algae

These are one of the photosynthetic synthetic organisms of the sea that are large enough to be seen without a microscope.

One species, green algae are common in freshwater. Their color comes from the chlorophyll in their composition.

Red Algae, is the most abundant and most widespread species. It varies is colors and sizes, but is found in warm and cold waters in the outer edge of the sublittoral zone.

Brown Algae, are another type that are found in the mid-latitudes, and in more cold water. These include kelp, which is the most largest algae.

Microscopic Algae

These are one of the photosynthetic organisms of the sea that are invisible to the naked eye.

They produce food for 99% of marine animals and are mostly planktonic phytoplankton.

An example includes, golden algae (chrysophyta), which are diatoms that are made of silica.

Coccolithophores

These are microscopic algae with calcium carbonate (CaCO3) shells, that form the base of many marine food webs.

They are found in temperate and warmer waters.

Dinoflagellates (Phylum Pyrrophyta)

These are microscopic algae that possess flagella for locomotion.

They have red pigments, which can lead to red tides when there is an algal bloom, this algal bloom in particular is very harmful since their is a decrease in dissolved oxygen ultimately killing fish.

These organisms cellulose are found to be promising for the development of functional materials of biomedical applications through biodegradation.

Harmful Algal Blooms (HABs)

This is the rapid increase in the concentration of algae in a body of water- which can be very harmful.

This increase of algae usually is occurs April through September and is the most dangerous in the Northern Hemisphere.

These may also produce toxins in the ocean and inadvertently consumed by fish and shellfish.

Paralytic Shellfish Poisoning (PSP)

If a human were to eat an affected fish/shellfish from a harmful algal bloom, they would get ______________ _______________ ___________________.

Ciguatera

This disease is caused by eating fish that have fed on toxic dinoflagellates.

Most common cause in seafood poisoning.

cultural

The speeding up of natural eutrophication is through human activities and is known as _______________ eutrophication.

Dead Zones

This is an area in a body of water, with extremely low oxygen concentration and very little life. Dissolved oxygen levels are usually less than 2 mg/L.

This area is anoxic and suffocates any bottom dwellers and less mobile organisms.

Usually located at the mouths of major rivers or at spring runoffs.

1960s, five (five hundred), coastlines

Global dead zone have been on a significant increase since the _______s. There are more than __ hundred worldwide. They are concentrated along _____________________.

Gulf of Mexico (Gulf of Mexico Dead Zone)

This is the second largest dead zone in the world.

It forms each summer.

The runoff of nutrients, fertilizers, and nitrates from Mississippi River drainage basin are what contribute to the algal blooms for this dead zone.

Photosynthetic Bacteria

These are photosynthetic marine organisms that are extremely small.

They exert critical influence on marine ecosystems and primary productivity.

Examples include:

Synechococcus

Prochlorococcus - the most abundant of all. They are half of the world ocean's photosynthetic biomass and are the most photosynthetic organism on earth.

one, 4000.

Regional primary productivity values vary from _____ gC/m^2/year to ________ gC/m^2/year. This variability is due to uneven distribution of nutrients and changes in the availability of sunlight.

Biological Pump

This is the removal of organic matter and nutrients from the euphotic zone to the deep water/sea floor through the sinking of dead surface dwelling organisms.

True

(T or F): Of the 9% of organic matter that is decomposed in the deep ocean, only 1% reaches the ocean floor.

False (Gyres prevent the resupply of nutrients through downwelling).

(T or F): Subtropical gyre thermoclines and pycnoclines increase the resupply of nutrients to the surface.

latitude

Globally, Annual primary productivity varies with _________________ because of thermocline/pycnocline and the impact of vertical mixing.

Polar Ocean Productivity

This explains how the productivity in polar oceans is primarily influenced by seasonal changes in sunlight and nutrient availability. In the summer there is more sunlight, the winter not as much; more dark.

Different types of plankton exhibit different patterns of productivity throughout the year: phytoplankton (diatoms) start to bloom in May. While zooplankton are mostly productive in June.

True

(T or F): Primary Productivity in high latitudes is limited by solar energy.

False (High latitude ocean waters are isothermal).

(T or F): Ocean waters in high latitudes change in temperature as depth increases.

reproduce

In the summer of polar ocean waters, plankton remain at the surface of the ocean and continuously __________________. This allows blue whales to wait for the maximum number of zooplankton to appear and eat them.

False (Blue whales primarily need zooplankton (specifically Krill) for their diet in order to grow).

(T or F): Blue whales do not need zooplankton as a part of their diet.

limits

In tropical oceans, nutrient availability ___________ primary productivity in tropics.

Equatorial Upwellings

Coastal Upwellings

Coral Reefs

In tropical oceans, what areas can there be high primary productivity?:

Availability of sunlight

Availability of nutrients

In temperate oceans, productivity is limited by?:

True

(T or F): With temperate oceans, there is a high seasonal productivity pattern. For example, the winter has many nutrients and little sunlight, whilst the summer has few nutrients and a lot of sunlight.

Spring Bloom

A middle-latitude (temperate ocean) bloom of phytoplankton that occurs during the spring and is limited by the availability of nutrients.

Fall Bloom

A middle-latitude (temperate ocean) bloom of phytoplankton that occurs during the fall and is limited by the availability of sunlight.

False (Mid-Latitude oceans).

(T or F): The highest overall productivity occurs in high latitude oceans.

Biotic Community (Biota)

This is known as the assemblage of organisms that interact within a definable environment or habitat.

Ecosystem

This refers to the biotic community and how it interacts with the abiotic environment.

uni(directional)

Energy flow is _____directional based on solar energy input.

entropy

Animals (heterotrophs) expend mechanical and heat energy. The residual energy then dissipates in their ecosystem as heat thus increasing ______________.

Producers

This is one of the three general categories of organisms in an ecosystem.

This type nourishes themselves with photosynthesis or chemosynthesis.

They are autotrophic.

Consumers

This is one of the three general categories of organisms in an ecosystem.

This type will eat other organisms.

They are heterotrophic

Decomposers

This is one of the three general categories of organisms in an ecosystem.

This type tends to break down dead organisms or waste.

They are heterotrophic.

Herbivores

This is a type of consumer that eats plants or algae.

Carnivores

This is a type of consumer that eats other animals.

Omnivores

This is a type of consumer that eats both plants/algae and animals.

Bacteriovores

This is a type of consumer that eats bacteria.

Detritus

These include the dead and decaying remains of the products produced by organisms.

Decomposers, like bacteria, break these down.

Biogeochemical Cycles

This is the pathway in which essential elements like carbon, nitrogen, and water follow through the Earth's ecosystems.

For example, decomposition is what converts organic molecules to usable forms of nutrients.

Suspension (Filter Feeding)

Benthic feeding strategy in which the organism takes in seawater and filters out usable organic matter.

Examples would be barnacles or clams.

Deposit Feeding

Benthic feeding strategy in which the organism takes in detritus and sediment and extracts usable organic matter.

Examples include detritivores.

Carnivorous Feeding

Benthic feeding strategy where an animal captures and eats other animals.

An example would include fish or sea stars.

Trophic Level

This refers to the level at which an organism is currently in on a food web.

Chemical energy is transferred from producers to consumers. Specifically, 10% of energy is transferred between each level.

Feeding population levels are slightly larger than prey levels.

Gross Ecological Efficiency

This refers to the ratio of energy passed to the next higher trophic level divided by energy received from the level below it.

The lowest trophic level has about 2% efficiency, while consumers have 10% efficiency.

Food Chain

This is the linear sequence of organisms through which energy is transferred.

A primary producer is preyed upon by an herbivore -> which in turn is preyed upon by one or more carnivores.

Fisheries target lower levels though, making them more efficient.

Food Web

This is the branching network of many consumers and their interconnected food chains.

Consumers in this branched network are more likely to survive as they have multiple prey/alternative food sources.

Oceanic Biomass Pyramid

This is a structured pyramid in which the number of individuals and total biomass decreases with each successive trophic level because of the amount of available energy decreases.

In this pyramid, organisms increase in size (physical size) as it moves up.

Standing Stock

This term refers to the amount (fish, according to this topic) of biomass present in a specific area or ecosystem at any given time.

Overfishing

This occurs when the fish stock has been harvested too rapidly.

This is because juveniles have not been sexually mature enough to reproduce.

You'd see a reduction in the Maximum Sustainable Yield (MSY), which is the just the average catch or yield that can be taken from a population.

80

_____ percent of 523 world marine fish stocks have either been fully exploited, overexploited, or depleted/recovering.

66 (million), 88 (million)

Today an average of ___ million tons of fish are harvested each year. In 1988, there was a peak at ____ million tons. This does not include bycatch, or illegal false reported catches.

Marine Mammal Protection Act (MMPA)

A US federal law that was enacted in 1972 (Textb. claims 1992) that prohibits the take of marine mammals, especially dolphins, from US citizens anywhere.

Purse seines, a method of harvesting marine animals, have been modified to easily release any dolphins caught.

This law has banned the use of Driftnets and Gill nets in 1989.

Fisheries Management

This is the process in regulating and overseeing fishing activity with the goal of maintaining a long-term fishery.

This is done by:

)Assessing stocks/ecosystems

)Analyzing fishing practices

)Establishing areas closed to fishing

)Enforcing catch limits

Human Employment

Self-sustaining marine ecosystems

International waters

Difficulty enforcing laws

What are some conflicting interests and challenges when it comes to regulating fishing:?

Ecosystem-based Fishery Management

This is a more holistic approach to manage fish stocks including fish habitat, migration/dispersal, and predator-prey dynamics.

This approach focuses on ecosystem and not a single species.