BCPS Outdoor Science Education
Review Sheet for Envirothon – AQUATICS
Student participants need to have a firm grasp of vocabulary and related aquatic
concepts in order to do well on the Aquatics section of the Envirothon competition. The
items on this review sheet cover the basic material on which students will be assessed. If
students are not familiar with the vocabulary and concepts, then additional research and
study time is recommended.
General vocabulary: (Refer to separate document for definitions and suggested use)
Alkalinity
Allochthonous
Anadromous
Anoxia/Anoxic
Autochthonous
Autotroph
Benthic
Brackish
Catadromous
Conductivity
Detritus
Estuary
Hardness
Heterotroph
Lentic Zone
Lotic Zone
Macroinvertebrate
Non-point Source Pollution
pH
Periplankton
Phytoplankton
Plankton
Point Source Pollution
Riparian Forest Buffer
Salinity
Turbidity
Watershed
Wetland
Zooplankton
Stream (lotic ecosystems) terminology: (Refer to separate document for definitions and
suggested use)
Base Flow
Channel
Discharge
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Pool
Reach
Riffle
Run
Sinuosity
Stream order – be able to define and label on a diagram
Stream Reach Perspectives: longitudinal, planiform, and cross-sectional
Water cycle terminology: Be able to draw and label the hydrologic cycle
Aquifer
Condensation
Evaporation
Groundwater
Infiltration
Percolation
Precipitation
Runoff
Surface water
Transpiration (sometimes called evapo-transpiration)
Relationships:
As water temperature decreases, Dissolved Oxygen (DO) level increases
As water temperature increases, DO level decreases
As salinity increases, water density increases
Water is most dense at 4°C, water freezes at 0°C (32°F), water boils at 100°C (212°F)
Healthy ecosystems usually have high species diversity with a variety of many species
but fewer individuals of each species
Unhealthy ecosystems often have low species diversity with low numbers of species but
higher numbers of individuals of each species
Water quality issues: Be able to describe process and impacts of the following
(refer to separate 3 page document set up as tables)
Acidification
Biological magnification
Soil erosion and sedimentation
Eutrophication
Pesticide runoff
Thermal pollution
Urbanization and impervious surfaces
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Aquatic food chains/webs:
Autotrophs – phytoplankton (including algae, diatoms, some dinoflagellates),
Submerged Aquatic Vegetation (SAVs) (e.g., wild celery, eelgrass, redhead grass),
Floating Aquatic Vegetation (FAVs) (e.g., duckweed), Emergent Aquatic Vegetation
(EAVs) (e.g., cattails)
Submerged Aquatic Vegetation (SAVs) are extremely important in aquatic
habitats since they not only are an important source of food but they also add
oxygen to the water, provide shelter to numerous heterotrophs, slow wave action
and erosion, and trap sediments and pollutants.
Heterotrophs – zooplankton (including some dinoflagellates), macroinvertebrate insects
(e.g., caddisflies, mayflies, stoneflies), shellfish (e.g., oysters, clams, mussels),
crustaceans (e.g., shrimp, crab), fish (e.g., rockfish – striped bass, white perch, bluegill,
brook trout), birds (e.g., great blue heron), mammals (e.g., muskrat)
Aquatic macroinvertebrates reflect the water quality of the stream.
Macroinvertebrates that are very sensitive to water pollution include stoneflies,
mayflies, and caddisflies. These organisms disappear quickly if water quality
deteriorates and their disappearance greatly impacts the stream food web since
they are fed upon by the higher level consumers. The greater the biodiversity of
macroinvertebrates, the greater is the biodiversity of fish and other organisms
(that depend on the macroinvertebrates for food).
Maryland aquatic invasive (non-native or exotic) species
Algae (diatoms) – Didymo
SAVs – Eurasian water milfoil, hydrilla, water chestnut
Wetland Plants - Phragmites, purple loosestrife
Invertebrates - zebra mussel, green crab, Chinese mitten crab
Fish - northern snakehead, brown trout, grass carp, common carp
Birds - mute swan
Mammals – nutria
Chesapeake Bay watershed:
 largest estuary in North America
 64,000 square miles
 approximately 16+ million people live in the Bay watershed
 six states (MD, VA, DE, WV, PA, NY) and Washington, DC
 50+ tributaries (Susquehanna River, Potomac River, James River, etc.
Salinity gradients in the Bay:
 Depth gradient: As depth increases, salinity increases
 North/South gradient: The farther north you go in the Bay, the lower the salinity
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The farther south you go in the Bay, the greater the salinity
East/West gradient: The more east you go in the Bay (towards the Eastern Shore),
the higher the salinity
The more west you go in the Bay (away from the Eastern Shore), the lower the
salinity
Fish anatomy and identification - remember to look at specific anatomical features and
know your vocabulary in order to use the Fish Key (refer to fish-specific handouts)
Fins
Mouth position
Lateral line
Rays/Spines
Scales
Barbels
Tail shapes
Thermal stratification of lakes and ponds: (Important terms are in bold print)
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The thermal stratification of lakes is due to changes in the temperature at different
depths in the lake. Temperatures change from season to season to create a cyclic
pattern that is repeated from year to year
In the winter (if the air temperature is cold enough), water freezes at the top due
to the most dense water (4°C) sinking to the bottom and the water at the surface
continuing to drop to freezing temperature (0°C) and forming ice
In the summer, water is usually warmer at the top and colder at the bottom
Oligotrophic (nutrient poor) lakes or ponds are more likely to show stratification
than eutrophic (nutrient rich) lakes or ponds because oligotrophic lakes are
deeper and usually have very clear water
Stratification layers form in deeper ponds or lakes – epilimnion (top layer),
hypolimnion (bottom layer), thermocline (area of rapidly changing temperature
and density between the epilimnion and hypolimnion layers)
Monomictic – a pond or lake forms stratification layers only once a year and has
one period of mixing per year
Dimictic –a pond or lake forms stratification layers twice a year and two periods
of mixing occur per year (usually referred to as the spring overturn and fall
overturn)
Other zones:
o Littoral – area around the edge of the body of water where photosynthesis
occurs
o Limnetic – layer of open water (away from the edge) where
photosynthesis occurs
o The littoral and limnetic zones are synonymous with the epilimnion
o Profundal – area of deep water where not enough light penetrates for
photosynthesis to occur (synonymous with the hypolimnion
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