6% Declines in phytoplankton over the last 10 years map right: Satellites Many of the areas showing an increasing trend appear along the coasts, in red, while most of the dark blue areas indicate a decreasing trend. Units for the top two panels are milligrams of chlorophyll per cubic meter.
Lakes are also damaged by acid rain. Fish die off, and that removes the main source of food for birds. Acid rain can even kill fish before they are born when the eggs are laid and come into contact with the acid.
Fish usually die only when the acid level of a lake is high; when the acid level is lower, they can become sick, suffer stunted growth, or lose their ability to reproduce.
Also, birds can die from eating "toxic" fish and insects.
Transport Currently, both the railway industry and the aeroplane industry are having to spend a lot of money to repair the corrosive damage done by acid rain. Also, bridges have collapsed in the past due to acid rain corrosion.
Humans can become seriously ill, and can even die from the effects of acid rain. One of the major problems that acid rain can cause in a human being is respiratory problems.
Many can find it difficult to breathe, especially people who have asthma. Asthma, along with dry coughs, headaches, and throat irritations can be caused by the sulphur dioxides and nitrogen oxides from acid rain.
Acid rain can be absorbed by both plants (through soil and/or direct contact) and animals (from things they eat and/or direct contact). When humans eat these plants or animals, the toxins inside of their meals can affect them. Brain damage, kidney problems, and Alzheimer's disease has been linked to people eating "toxic" animals/plants.
Since the Industrial Revolution Concentration of Carbon Dioxide from trapped air measurements for the DE08 ice core near the summit of Law Dome, Antarctica. (Data measured by CSIRO Division of Atmospheric Research from ice cores supplied by Australian Antarctic Division)
The ctenophore Mnemiopsis , introduced to the Black Sea and Caspian •Island populations are particularly sensitive to introductions. The introduction of goats to Abingdon island in the Galapagos wiped out the abingdon tortoise
Biodiversity is highest in the tropical Rainforest
Ethical reasons for conserving biodiversity are that all species have a right to live on this planet.
Ecological reasons are that species live with great interaction and dependence on each other. If one species dies out, a food chain is disrupted, therefore disrupting all of the other species as well.
Economic reasons are that the rainforest is a source of materials important to human life. Medicinal substances can be taken from a variety of plants in the rain forest, and ecotourism offers a new source of funds for the many impoverished nations these forests exist in.
The index of diversity is used as a measure of the range and numbers of species in an area. It usually takes into account the number of species present and the number of individuals of each species. It can be calculated by the following formulae:
D = N(N-1) ∑n(n-1)
D= Diversity index
n = number of individuals of a each species found in an area.
N = total # of organisms of all species found in an area.
The simpson diversity index is a measure of species richness.
A high value of D suggests a stable and ancient site.
In extreme environments the diversity of organisms is usually low (has a low index number). This may result in an unstable ecosystem in which populations are usually dominated by abiotic factors . The abiotic factor(s) are extreme and few species have adaptations allowing them to survive. Therefore food webs are relatively simple, with few food chains, or connections between them – because few producers survive. This can produce an unstable ecosystem because a change in the population of one species can cause big changes in populations of other species.
species abundance of both individual and/or groups of interacting species. Overexploitation may include over fishing and over harvesting
Historically, humans have fished the oceans, which never seemed to pose a problem due to their abundant resources. Gear (fish trap, gill nets, electro-fishing) and vessel efficiency modifications have caused a significant decrease in fish populations.
A fishery is an area with an associated fish population which is harvested for its commercial or recreational value. Fisheries can be wild or farmed.
Population dynamics describes the ways in which a given population grows and shrinks over time, as controlled by birth, death, and emigration or immigration. It is the basis for understanding changing fishery patterns and issues such as habitat destruction, predation and optimal harvesting rates.
The population dynamics of fisheries is used by fisheries scientists to determine sustainable yields
Virtual Population Analysis is a modeling technique commonly used in fisheries science for reconstructing fish numbers using information on death of individuals each year. This death is usually partitioned into catch by fishing industry and natural mortality.
Capture-Mark-Recapture Method day one, mark and release the fish. The next day, repeat the sequential sampling and also records the total number of fish marked and unmarked so we can use to estimate of fish population density.
The overall catch has decreased fish stocks in many areas of the United States, as catches in each area exceed the maximum number of fish that these fishermen are allowed to take.
Age structure : If all the age groups are harvested recruitment of young fish into the reproductive group will be reduced. The answer is to use a net with a big enough mesh size that lets the young fish escape
Limiting factors : If the limiting factors in the environment change so does the population growth rate
Limiting factors set the carrying capacity (K) of an environment
Increasing limiting factors will cause K to drop
Fixed quotas cannot cope with this
Data: For MSY to work accurate data in fish populations is needed (population size, age structure, recruitment rates)