Imperiled Freshwaters Quiz 2 Terms

Pollution

• Human manufactured or human-derived contaminant of a natural system

• Natural substance that increases in concentration to problematic levels due to human activities

Point source pollution

localized and stationary source of pollution

Non-point source pollution

diffuse pollution that does not come from a single discrete source

Limiting factor

environmental condition that restrict growth, distribution, or abundance of organisms

Law of the minimum

whatever nutrient that is in lowest abundance relative to demand will limit growth

Top down food web regulation Bottom up food web regulation Nitrogen fixation

Top-down food web regulation refers to how predator populations control the structure and dynamics of prey populations within an ecosystem, while bottom-up food web regulation emphasizes how resource availability, like nutrients and energy, influences the populations of organisms. Nitrogen fixation is the process by which certain organisms convert atmospheric nitrogen into a form that plants can use.

Bioavailable

• able to be taken up by or consumed by organisms

Internal phosphorus loading/nutrient regeneration

The release of phosphorus from sediments back into the water column, often triggered by changes in water chemistry or anaerobic conditions, which can contribute to algal blooms and eutrophication.

Acute exposure

• refers to the short-term exposure of an organism to a toxic substance at high concentrations.

• large pulse over short period of time

Chronic exposure

• refers to the long-term exposure of an organism to a toxic substance at low concentrations, often over an extended period of time.

• low doses over long periods of time

Lethal response

causing death

Non-lethal response

not causing death

Instantaneous response

immediate response

Cumulative response

response to numerous exposures

Carcinogenic

• increasedformationofcancerouscells

Native species

• species that evolved in the local environment or that dispersed to the environment by natural means

• Native communities generally evolve together

  • Species evolve or arrive to fill open niches, or roles, in the ecosystem

  • Populations and communities are generally stable over time (but still dynamic!).

Exotic species

• a species transported by humans outside its natural range and introduced into a new environment*

  • AKA: alien species, non-native species, non-indigenous species

Invasive species

• an exotic species that persists and reproduces in its new environment and spreads greatly in distribution

• MAY negatively impact new environment or human interests

Establishment

• Introduced species develops a reproducing population

  •Not all introduced species become established
  

Environmental filters

• filters: conditions that prevent species from establishing

• Temp, light, water availability, shelter, salinity, water chemistry

Biotic filters

• Filters: conditions that prevent species from establishing

• Predators, food availability, parasites and pathogens, competition

Spread

• expansion of the area the newly established species occupies

• This depends on how well the newly established species: • Reproduces

• Disperses locally

Biodiversity

the number of different species in a community

Invasional meltdown

• Previous invasions lead to more invasions

• Direct or indirect positive interactions among invasive

Haber-Bosch process

synthesizes ammonia (NH₃) from nitrogen (N₂) and hydrogen (H₂) using high pressure (~150-300 atm), high temperature (~400-500°C), and an iron-based catalyst

Algal bloom

• a rapid increase in algae in water, often caused by excess nutrients like nitrogen and phosphorus from pollution. Some blooms produce toxins (harmful algal blooms, or HABs) that harm aquatic life and humans. They can deplete oxygen, leading to dead zones where marine life cannot survive. Common causes include agricultural runoff, wastewater discharge, and climate change.

Harmful algal bloom (HAB)

Algal blooms that cause harm to the ecosystem, humans, human livelihoods, human lifestyles

• unsightly

• smells bad

• hamper boating and recreation

• decrease drinking water quality

• reduce oxygen in water → kills fish

cyanobacteria

• Photosynthetic bacteria grouped with algae

• Sometimes called blue green algae Ancient and amazing organisms! Natural part of algal community

Cyanobacteria HAB

• an algal bloom composed of cyanobacteria

• CyanoHABS are a common type of HAB in freshwater ecosystems

Mutagenic

• increased mutation rate in cells

Teratogenic

• increased rate of birth defects

Lethal dose 50 (LC50)

• concentration that causes death. Subscript denotes % mortality

Effective concentration 50 (EC50)

• concentration that causes some effect other than death. Subscript denotes % showing effect

Bioconcentration

• compounds move into organisms from the water

Bioaccumulation

• bioconcentration plus the amount acquired from food.

Biomagnification

• increase in concentration from the bottom to the top of the foodweb

Propagule pressure

Propagules are units that are able to reproduce

• Individuals (asexually reproducing)

• Fragments

• Seeds

Propagule size

the number of individuals arriving during an introduction event

Propagule number

the number of introduction events

Suspension feeder

• eat algae suspended in the water

Piscivorous

are animals that primarily eat fish. They can be found in various ecosystems, including oceans, rivers, and lakes. Examples include sharks, dolphins, ospreys, penguins, and some large fish like pike and barracuda. Piscivores play a crucial role in maintaining aquatic food chains by regulating fish populations.

Planktivores

organisms feed on plankton, including tiny animals (zooplankton) and plants (phytoplankton). Examples include small fish like anchovies and baleen whales. They play a key role in aquatic ecosystems.

Ecosystem engineers/engineering

changing the physical structure

Biotic resistance

The biodiversity of an ecosystem allows it to resist invasion

• Biodiversity: the number of different species in a community

• Diverse communities have strong interspecies interactions • Competition

• Predation/herbivory • Parasitism

Ballast water

is water carried in ships' tanks to maintain stability and balance. It is taken on in one location and discharged in another, often carrying various marine species, which can lead to the spread of invasive species and environmental issues when released into different ecosystems.

Natural eutrophication

accumulation of nutrients in a waterbody, increasing the productivity of that waterbody

Cultural eutrophication

accelerated eutrophication of a waterbody due to human activities.

Oligotrophic lake

• Low nutrient concentration

• Low productivity

• Lots of light

• Lots of oxygen

• “young”lake

Eutrophic lake

• High nutrient concentration

• High productivity

• Less light

• Low oxygen at the bottom

• “aged”lake

Mesotrophic lake

• moderate level of nutrients, such as nitrogen and phosphorus.

• balanced ecosystems, with healthy levels of plant and animal life.

• They are often characterized by clear water and support a variety of fish species.

Algae

• Single or multicellular, plant like organisms that photosynthesize

-Diverse Important components of lake food webs Regulate lake oxygen dynamics

Eutrophication

• accumulation of nutrients in a waterbody, increasing the productivity of that waterbody

• More nutrients enter the lake
  More aquatic plants, more algae Sediments build up

• More decomposition of dead plants/algae