Aquatic Biomes and Ecosystems

Aquatic Biomes

• Salinity refers to the amount of salt in a body of water, dictating which species can survive there.
• Water depth affects sunlight penetration, crucial for plant photosynthesis below the surface.
• Water flow influences oxygen levels, determining the survival of plants and organisms.
• Temperature affects dissolved oxygen levels; warmer water holds less oxygen, supporting fewer aquatic organisms.
• Rivers have high oxygen levels due to flowing water mixing with air and carry nutrient-rich sediments.
• Lakes are standing bodies of freshwater, divided into zones.
• The littoral zone is shallow with emergent plants.
• The limnetic zone allows light penetration, enabling photosynthesis but lacking rooted plants, with phytoplankton present.
• The profundal zone is too deep for sunlight to reach for photosynthesis.
• The benthic zone is the murky bottom with nutrient-rich sediments, inhabited by invertebrates.
• A wetland is an area with soil submerged or saturated in water for at least part of the year, shallow enough for emergent plants.
• Wetland plants are adapted to submerged roots.
• Wetlands store excess water during storms, reducing floods, and recharge groundwater by absorbing rainfall.
• Wetland plant roots filter pollutants, and high water and nutrient levels support abundant plant growth.
• Estuaries are where rivers meet the ocean, mixing fresh and saltwater, leading to high productivity.
• High nutrient levels in sediments are deposited by rivers.
• Salt marshes are estuary habitats in temperate climates, serving as breeding grounds for fish and shellfish.
• Mangrove swamps are estuary habitats along tropical coasts.
• Coral reefs are diverse marine biomes in warm, shallow waters, featuring a mutualistic relationship between coral and algae.
• Coral provides CO2 to algae and creates a calcium carbonate exoskeleton and algae supply sugar (energy) to coral through photosynthesis.
• Intertidal zones are coastlines between high and low tide, where organisms must withstand waves and sunlight/heat.
• Intertidal organisms like barnacles, sea stars, and crabs have tough outer shells.
• These shells prevent drying out (desiccation) during low tide.
• Open oceans have low productivity per area, supporting mostly algae and phytoplankton.
• Open oceans produce much of Earth's oxygen and absorb atmospheric CO2.
• The photic zone is where sunlight reaches for photosynthesis.
• The aphotic zone (abyssal) is too deep for sunlight.

Carbon Cycle

• The carbon cycle involves carbon molecules moving between sources and sinks.
• Fossil fuel digging releases carbon into the atmosphere faster than natural processes.
• Global temperature is directly related to carbon increase.
• Carbon sinks store more carbon than they release (e.g., ocean, plants, soil).
• Carbon sources release carbon into the atmosphere (e.g., fossil fuel combustion, animal burps, deforestation, cellular respiration).
• Photosynthesis removes CO2 from the atmosphere, converting it to glucose and serves as a CO2 sink.
• Cellular respiration breaks down organic compounds for energy, releasing CO2.
• Cellular respiration and photosynthesis cycle carbon between the biosphere and atmosphere quickly.
• Direct exchange allows CO2 to move between the atmosphere and ocean, influencing ocean CO2 levels and acidification.
• Algae, phytoplankton, coral reefs, and shelled organisms use CO2 in the ocean.
• Sedimentation is the process of marine organisms dying where their carbon containing remains sinks to the ocean floor.
• Burial is the compression of carbon sediments into sedimentary stone, creating long term storage of C.
• Fossil fuels form from fossilized organism remains, storing carbon.
• Extraction and combustion involve digging up/mining and burning fossil fuels, releasing CO2.
• Fossil fuel formation (burial) is slower than extraction and combustion.
• Fossil fuels are extracted and combusted at a higher rate than their formation leading to increased CO2 in the atmosphere.

Nitrogen Cycle

• The nitrogen cycle involves nitrogen-containing molecules moving between sources and sinks.
• Sources release nitrogen into the atmosphere.
• Sinks remove nitrogen from the atmosphere..
• Nitrogen reservoirs hold nitrogen for a short time compared to the carbon cycle.
• The atmosphere is the largest nitrogen reservoir, existing as unusable N2 gas.
• Nitrogen fixation converts N2 gas into usable NH3 or NO3.
• Nitrogen is critical for DNA and amino acids.
• Nitrogen fixation can be natural (bacteria, lightning) or synthetic (combustion).
• Bacterial fixation involves symbiotic bacteria and plant root nodules.
• Synthetic fixation involves combusting fossil fuels to produce fertilizers.
• Assimilation involves plants and animals taking in and incorporating nitrogen to build proteins and DNA.
• Plants access nitrogen directly from the soil, while animals consume plants or other animals.
• Ammonification is when Soil bacteria converting waste and dead biomass back into NH3 and returning it into the soil.
• Nitrification converts NH4 into nitrite (NO2) and then nitrate (NO3) by soil bacteria.
• Denitrification converts soil NO3 into nitrous oxide (N2O) gas, returning it to the atmosphere.
• Nitrous oxide (N2O) release contributes to climate change, while ammonia volatilization leads to acid rain.
• Volatilization also results in loss of nitrogen for crops.
• Synthetic fertilizer use can cause nitrate leaching, entering water bodies and fueling algae growth.

Phosphorus Cycle

• The phosphorus cycle involves phosphorus atoms moving between sources and sinks.
• Major phosphorus reservoirs are rocks and sediments.
• The phosphorus cycle is slow, lacking a gas phase so it does not enter into the atmosphere.
• Phosphorus weathering is a slow process.
• Phosphorus is a limiting nutrient
• All organisms need phosphorus for DNA, ATP (energy), and bone/tooth enamel.
• Phosphorus sources include weathering of rocks containing phosphorus minerals.
• Synthetic sources come from mining phosphate minerals for fertilizers and detergents.
• Plant roots absorb phosphorus and assimilate it into tissues which is then passed into animals and biomass.
• Decomposers then return phosphate to the soil.
• Sedimentation involves phosphate settling to the bottom and compression into sedimentary rock.
• Geological uplift can restart the cycle by exposing rock. The phosphorus cycle begins again with weathering and phosphate release from rock.
• Eutrophication occurs when excess nutrient input which can fuel algae growth.

Hydrologic (Water) Cycle

• The water cycle involves water (H2O) - in different states - between sources and sinks
• H2O cycle is driven by the sun
• The largest reservoir is the ocean.
• Smaller reservoirs are ice caps and groundwater.
• Transpiration and evaporation are key processes that cycle water from liquid to a gas which goes back into the atmosphere.
• Plant stomata release water into the atmosphere, creating a low H2O potential in the leaf.
• Evaporation is when liquid water changes to a gas via the energy of the sun.
• Evapotranspiration is the combined amount of H2O that enters atmosphere from transpiration and evaporation.
• Runoff flows over the surface while Infiltration trickles through the soil down into groundwater aquifers.
• Groundwater aquifers and surface waters are important as they are often exploited by humans and animals.
• Runoff recharges surface waters, but can also carry pollutants.

Primary Productivity

• Primary productivity is the rate at which solar energy is converted into organic compounds.
• It is measured in kcal/m^2/year.
• Higher productivity supports more plant growth, resulting in more biodiversity.
• Respiration loss (RL) involves plants using energy generated by photosynthesis.
• Gross Primary Productivity (GPP) is the total solar energy captured by plants and turned into glucose through photosynthesis.
• Net Primary Productivity (NPP) is the energy leftover for consumers after plants use some for respiration (NPP = GPP - RL)
• Ecological efficiency refers to the portion of solar energy captured by plants and converted into biomass
• 99% of solar energy is reflected or passes through producers without being absorbed.
• Only 1 percent of solar energy striking producers is captured by photosynthesis.
• 40% of GPP supports the growth and reproduction of producers.
• High water availability, temperature, and nutrient availability enable high NPP.

Trophic Levels and the 10% Rule

• Matter and energy are conserved, meaning they change forms (never created or destroyed).
• Energy is never created or destroyed (1st law of thermodynamics).
• Biogeochemical cycles demonstrate conservation of matter.
• Every time energy is transferred, some is lost as heat (2nd law of thermodynamics).
• Trophic pyramids illustrate energy movement through an ecosystem from the bottom up.
• The 10% rule dictates only 10% of energy transfers to the next level.
• Producers (plants) convert sunlight into chemical energy (glucose).
• Primary Consumers are herbivores.
• Secondary Consumers are carnivores and omnivores.
• Tertiary Consumers are animals that eat secondary consumers.
• Example - 1000 kg producers can only support 100 kg of primary consumer, 10 kg of secondary consumer, 1 kg of tertiary consumer.

Calculating Biomass or Energy

• Move the decimal place one spot to the left from one trophic level to the next trophic level (or divide by 10).

Food Webs and Chains

• A food web shows matter and energy flow through an ecosystem.
• Arrows in a food web indicate the direction of the energy flow.
• A food chain is one simple pathway of energy and matter.
• A food web comprises at least two connected food chains.
• Food webs show how population changes impact the ecosystem.
• A trophic cascade occurs when the removal or addition of a top predator affects lower levels.

Intro to Biodiversity

• Biodiversity is the diversity of life.
• Ecosystem diversity is the habitats in a given area.
• Species diversity is the number of different species in an ecosystem.
• Genetic diversity is the differences in genes of individuals within a population.
• Higher biodiversity means higher ecosystem and population health.
• Richness is the total number of species in an ecosystem.
• Evenness measures how balanced an ecosystem is between different species.
• Genetic diversity helps populations respond to environmental stressors.
• Random mutations can cause these variations in the genomes.
• Bottle neck events reduce the size and genetic diversity of an environment when organisms die at random.
• Inbreeding increases chance of harmful mutations and is closely related to family members.
• Ecosystem resilience is ability of ecosystem to return to its original condition after a big disturbance.
• Higher species diversity contributes to higher resilience.

Ecosystem Services

• Ecosystem services provides Measurable economic/financial goods and functions to humans.
• Provisioning services are the goods/products provided to use by ecosystems.
• Regulating services benefits provided by ecosystem processes that moderate natural conditions like climate and air quality.
• Supporting services are natural ecosystems that process functions to support us which can lead to a cheaper and more efficient way of living.
• Cultural services money generated by recreation through activities such as tourism, scientific discoveries made in ecosystem etc.

Island Biogeography

• Island biogeography studies ecological relationships on islands.
• Larger islands support more species due to greater ecosystem diversity; islands closer to the mainland support more species.
• Easier travel to the island supports a larger number of species.
• Larger islands have more genetically diverse species.
• Frequent migration brings more, larger more genetically diverse species and population size.
• Closer to mainland means higher species richness - opposite for Further from mainland -.
• Limited space in island will pressure species to adapt to new niches.
• Adaptive radiation where a single species evolves to several new ones.

Ecological Tolerance

• Ecological Range of Tolerance is range of conditions such as temperature, salinity, pH, or sunlight that an organism can endure before injury or death
• Species and individual organisms have a range of tolerance for all the different environmental conditions of their habitat
• Optimal range is where the organism survives and reproduce.
• Physiological stress zone s where the organism can survive but has to experience stress.
• Intolerance zone zone is the range where the organism is going to die.

Natural Disruptions to Ecosystems

• Natural Disturbances are Natural events that disrupt structure or function of an ecosystem
• Natural disturbances can occur on periodic, episodic, or random timeframes.
• Changes in the Earths tilt can influence the temperature over a long period.
• Wildlife wildlife may migrate as a result of natural disruptions.

Adaptations.

• All populations have some genetic diversity, or variability in genomes of individuals
• Adaptation - a new trait that increases an organism’s fitness (ability to survive and reproduce)
• Natural selection - organisms that are better adapted to their environment survive and reproduce more offspring
• Selective pressure and force - the environmental condition that kills individuals that don’t have the adaptation
• Environment an organism lives in determines which traits are adaptations
• The more rapidly an environment changes, the less likely a species in the environment will be to adapt to those changes
• The more rapidly an environment changes, species may migrate out of, or die out.
• Environmental change decreases ability to adapt and increases morality.
• The longer the lifespan of the organism, the slower the rate of evolution.

Ecological Succession

• Ecological Succession a series of predictable stages of growth that a forest goes through.
• Primary Succession starts from bare rock in an area with no previous soil.
• Moss and lichen spores carried by the wind grow directly on rocks, breaking them down to form soil.
• Weathering of rocks combined with organic matter from moss and lichen FORMS INITIAL SOIL
• Secondary Succession starts from previously established soil in an area where a disturbance cleared out majority of plant life.
• Pioneer species are still the first species that arrive in this area through wind.
• Pioneer or early successional species appear first, when the ground is simply bare rock or soil due to recent disturbances.
• EXAMPLE Moss, lichen (bare rock) or wildflowers, raspberries, grasses/sedges
• Mid successional species appear after pioneer species have developed soil with more nutrients by cycles of growth and death
• Shrubs and fast trees can appear here and are sun tolerant
• Late successional species or climax community species appear last, after soil is depend and enriched with nutrients by cycles of growth and death by early and mid successional species.

Specialist and Generalist Species

• Specialists - smaller range of tolerance, or narrower ecological niche makes them more prone to extinction.
• Specific food requirements means less ability to adapt to new conditions.
• Generalists have Larger range of tolerance, broader niche makes them less prone to extinction and more likely to be invasive.
• Broad food requirements means high adaptability.

K-selected and r-selected species

• K-selected species have few offspring and heavy parental care.
• Usually reproduced many times and have long lifespan and long time to sexual maturity means low biotic potential means slow population growth rate.
• K-selected is more likely to be disrupted by environmental changes or invasive species.
• Have lower reproduction rate.
• r-selected species produce many offspring and have little parental care and often reproduce only once.
• Often Insect, fish, plants.
• r-selected Often shorter lifespan and are quick to sexual maturity means high biotic potential means high population growth rate.
• r-selected Have high biotic potential so need to reproduce more and more to ensure that at least some of them will survive.
• Is often more likely to be invasive.
• K-selected Long life span slow population growth rate, stable and are regulated by density dependent factor.
• R-selected Short life span fast population growth rate highly variable are regulated by an Independent factor.

Survivorship Curves

• A survivorship curve is the relative survival rates of a group of individuals of the same age in a population
• Type 1 has Low survivorship early in life and then steady decline as age gets older.
• Type two steadily decreasing survivorship throughout life.
• Type three have High survivorship early in life and then steep decline in old age.

Carrying Capacity

• Carrying Capacity (k) is Number of individuals in a population that an ecosystem can support
• Highest population size an ecosystem can support is based on food, water and habitat
• Die-Off - sharp decrease in population size when resource depletion (overshoot)
• When populations exceed carrying capacity, there is overshoot
• If resource depletion is severe, there can be total population crash

Population Growth and Resource Availability

• Population growth is limited by environmental factors, especially by the available resources and space.
• Population characteristics
  • Size - total number of individuals in a given area at a given time
  • Density - number of individuals per area
  • Distribution - how individuals in population are spaced out compared to each other
  • Sex ratio - Ratio of males to females
  • Limiting resources can prevent population growth Population size - (immigrations + births) - (emigrations + deaths)