exam 3 Marine Ecology

Ecosystem

The biological community and physical environment within a relatively closed system, in terms of energy flow and cycling of matter

Autotroph

Create own food through things in the environment

Primary productivity

the rate a primary producer incorporated energy into their productivity

Gross primary productivity (Gpp)

Total rate of energy incorporation into primary producers

• can be measured

Net primary productivity (NPP)

Rate of energy incorporation into primary producers minus energy needed to satisify growth and maintenance, via cellular respiration (ATP)

• NPP=GPP-rate of respiration

Net primary productivity measurement

NPP = GPP - rate of respiration

Measuring primary production

Oxygen uptake

Net rate of O² production=direct measure of photosynthesis

Measuring primary production

Radiocarbon technique

measurement of ¹⁴C uptake over time (used as a tracer to follow incorporation of carbon)

• Estimates the uptake and assimilation of CO²

Measuring primary production

Chlorophyll concentration

Rate of photosynthesis based on chlorophyll concentration in seawater samples

• standing measure (not a rate)

Measuring primary production

Satellites/remote sensing

Senses the color of light bouncing off of the water which shows chlorophyll A in the water

Nutrient

chemical that promotes life (survival, growth, and reproduction in a living orgnanism)

Redfield ration

average ratio of nutrient uptake by marine phytoplankton (106 Carbon, 16 nitrogen, 1 phosphorus, 0.0075 iron)

Three carbon cycle pumps

1. Solubility pump

2. Carbonate pump

3. Biological pump

Nitrogen

Most limiting macronutrient in marine environment

high-nutrient low-chlorophyll regions

areas of the ocean where phytoplankton abundance is lower than expected, despite high concentrations of macronutrients

Food chain

Linear sequence showing which orgnaisms consume which other organisms, making a series of trophic levels

Food web

More simple diagram

Grazing

Eaten alive (plankton and plants)

Biodiversity

• increase productivity

• create more resilient ecosystems in the face of environmental change

• be directly valuable to us (ex food, medicine)

Genetic markers

allow identification of population (genome sequencing, mitochondrial DNA)

Individual Species

preserve abundance of target species ( usu charasmative megafauna)

Total biodiversity

focus on hotspots of high diversity

Ecosystem dunction

Concern is focused on species that are important in ecosystem processes, such as primary production, nutrient cycling, and decomposition

Ecosystem services

Ecosystems have human value that can be quantified in money (resources, water supply)

Invasion

Arrival of a species to an area that has not lived there previously

Vector

Means of transport must be available (ex. Ballast water of ships)

Regulation

not allowed to release ballast water while in actual water

Marine Protected Areas

Regulated regions that were established to protect ecosystems, preserve cultural resources (ex Shipwrecks, archeological sites) or sustain fisheries

Atlantic Cod

Overfished to the point of genetic drift

Stocks

Populations that reproductively isolated

• Fisheries do so for management

• Identified with acoustic tags and/or molecular markers

Drift nets

For catching animals at the top of the water column

Floating longline

for catching things in the middle

Otter reawl

Drags along the floor

• bad for benthic organisms

Bycatch

Unintended catch

Avoiding bycatch

• turtle exclusion devises

• specialty trawl nets

• circle hooks are less likely to cause internal damage than J-hooks

• fishing at night to avoid seabird bycatch

• avoiding “hot spots”

Smart fish regulations

to produce a good fisheries model, we must account for all contributions to reproduction, growth, and mortality throughout the life cycle of the fishery resource species

Tragedy of the commons

Economic principle that individuals overexploit a shared resources for self gain