Aquatic Buomes

• High Tides - Full Moon/ New Moon - Highest High Tide and Lowest Low Tides

• Low Tides - Third Quarter Moon/ First Quarter Moon - Lowest High Tide and Highest Low Tide 

As tide rises and falls, extreme variation in:

• Wave action (physical disturbance can be high or low depending on location.

• Temperature (extreme heat vs cold)

• Water (desiccation)

• Salinity (high salinity with
  evaporation of salt water and proximity to ocean, low salinity with freshwater runoff from terrestrial environments).

Rocky Intertidal

Common adaptations 

• Attachment devices

• Hard shells that can be tightly closed 

• Holding water inside shells

• Thick outer skins

Estuaries and Salt Marshes

• Estuary: semi-enclosed coastal water body connected to open sea where seawater is measurably diluted with fresh water from lotic systems

• Salt marshes: estuarine marsh communities that contain non- woody emergent vegetation & generally occur in areas protected from wave action

Characteristics of Estuaries/ Salt Marshes

• Low grade slope means minimal disturbance from waves, so muddy substrate needed for plants is maintained. Waves would suspend and wash away mud.

• Contain abundant nutrients and sediments carried downstream by rivers (supports extremely high biological productivity).

• Estuaries often surrounded by tidal salt marshes, which are some of the most productive habitats on Earth.

• Important hatcheries for many species of commercially and ecologically important fish.

Neritic zone

• Waterbodyover the continental shelf

• Stablesubstrate, water, light, and temperature.

• Locationof majority of diversity of sea life, including corals and kelp forests.

Coral reef distribution highly restricted

-Major Neritic ecosystem in tropical regions.

• Water temperatures remain between 68-83°F.

• 30-100 ft of the euphotic zone (shallow, sunlit waters)

• Salinity 35-38 ppt, Low turbidity (clear water).

• Extremely high diversity

• All coral reefs owe their existence to an important symbiotic relationship.

• Coral are Ecosystem Engineers and Keystone Species!

Types of Reefs 

• Actve Volcano

• Barrier Reef

• Frindging Reef

• Atoll

Kelp forests found at higher latitudes

• Major Neritic ecosystem in temperature and cold regions.

• Water temperatures between 42 and 72 °F

• Found in areas of oceanographic upwelling, a process delivering cool, nutrient-rich water from depth to the ocean's surface.

• Dominated by Brown Algae (order Laminariales).

• Provide refuge, shelter, and feeding grounds to diverse species.

• Kelp are also Ecosystem Engineers and Keystone species!

Characteristics of Open Ocean (Oceanic)

• One of the least studied ecosystems on the planet

• Encompasses wide range of habitats from Arctic, Antarctic, to Tropical and Subtropical waters (most of what you see on a global map of oceans is the Oceanic)

• Algae major source of primary production, but only in surface waters

• Commercial fish populations (overharvesting a significant threat)

Epipelagic zone (photic zone)

• To ~ 660 feet depth.

• Zone where enough light is available for photosynthesis.

• Majority of ocean photosynthesis occurs in epipelagic zone of the oceanic.

• Below the Epipelagic, organisms rely on the Biological Carbon Pump for organic matter 

Biological Carbon Pump

• Plants remove CO2 from the surface water where it is dissolved and transform it into living matter through photosynthesis

Mesopelagic zone

~660-3000 ft

• Not enough light for photosynthesis, transitioning to complete darkness at bottom.

• Example organisms include heterotrophic bacteria, swordfish, squid (many bioluminescent).

• Many organisms rise to the epipelagic zone at night to feed.

Bathypelagic zone

• Pitch black (no light)

• 3300 to 13000 ft

• animals survive by predation or consuming the detritus falling from above "marine snow“.

• squid, octopus, anglerfish, hatchet fish, many with bioluminescence.

Abyssopelagic zone

13,000-18,000 ft

(abyssal zone)

• Pressure 500x standard atmospheric pressure.

• 0-3 °C around the world

• squid; echinoderms, basket star, swimming cucumber, and sea pig; sea spider.

• Many species transparent and eyeless.

Hadalpelagic zone

18,000-35,000 ft
(Mt Everest = 29k altitude

• Deepest trenches in ocean (Mariana Trench 7 miles deep)

• Pressure 1000x standard atmospheric pressure.

Important abiotic factors differentiating marine ecosystems:

• 1)  Light

• 2)  Temperature

• 3)  Salinity

• 4)  Oxygen

• 5)  Pressure

• 6)  Nutrients

(1) LIGHT

• Decreases with LATITUDE at the surface (like terrestrial environments, light intercepted by water is function of both angle of incidence and hours sunlight)

• Also decreases with DEPTH.

• All primary production (photosynthesis) is in Epipelagic zone

Ultraviolet = 10 -400 nm 

Visible light = 400 -780 nm 

Infrared = 780nm -1mm 

nm = nanometers

(2) Temperature

Surface temperature decreases with LATITUDE

Temperature also decreases with depth

Change in temperature with increasing depth depends on latitude.

• Temperature at the ocean’s surface varies greatly with latitude

• Temperature of deep water (below mesopelagic) varies little with latitude

Coral reefs extremely sensitive to high temperature

Coral bleaching event (a marine heat wave):

• At high temperature, symbiotic zooxanthellae produce reactive oxygen species toxic to coral.

• Coral expels zooxanthellae shortly before dying.

Organisms at poles adapted to extreme cold may also be affected by warming oceans

(3) Salinity

varies slightly at ocean surface

• Higher salinity around 30 northand 30 south latitude(where freshwater precipitation is low)

• Lower Salinity At Equator(where freshwater precipitation is higher)

• Lowest Salinity At Poles(where melting is very high).

• Salinity also changes with depth

• Surface factors: • Precipitation • Melting ice

Osmoregulation- Managing salinity

Osmosis: water passes through semipermeable membrane to location of highest solute concentration.

To maintain salt balance, fish have evolved to:

1) retain water
2) use their gills and kidneys to secrete solutes.

Tree Swallow

(4) OXYGEN (O2)

Profile between 0 and 60 N latitude

oxygen initially decreases with depth to a minimum at bottom of Mesopelagic (twilight zone)

The decrease is function of:

• Diffusion of atmospheric oxygen into water (only occurs at surface).

In contrast with oxygen at low latitudes, at North Pole oxygen is higher at surface and changes little with depth.

Oxygen concentrations affected by temperature:

Poles:

• High saturation concentration of oxygen in cold water

• High mixing due to lack of a strong thermocline

• Rapid transport to deep water due to water currents.

Tree Swallow June 9, 2021

Lenape Park, Uni

Equator:

• Low saturation concentration of oxygen in warm water

• Strong thermocline limits mixing of surface with deep waters.

• Deep waters with higher oxygen come from poles!

Tree Swallow June 9, 2021

Lenape Park, Uni

Antarctic and polar water sinks and travels (slowly) between oceans and towards equator in deep currents

(5) Water pressure

Pressure increases one atmosphere for every 33 feet (10.06 meters) increase depth.

Pressure at sea level:
• 14 psi (pounds per square inch)

Pressure at 35,000 feet depth:

• 16,000 psi

• No light and near freezing temperature!

• Organisms found there are highly adapted to great pressure, so can’t survive outside that environment.

(6) Nutrients

errestrial sources can also cause extreme oxygen depletion in coastal waters:

Hypoxic water:

Dissolved oxygen concentrations less than 2-3 mg/L.

Anoxic water:

Dissolved oxygen concentrations ~0 mg/L.

Effects:

Ability of marine species to survive low dissolved oxygen not well documented.

A remarkable number of Eutrophic and Hypoxic coastal sites exist around the world.

Surface currents (different from deep ocean currents) form part of five major oceanic gyres.

urface currents are driven by global patterns of air circulation that result from Coriolis force.

Earths rotation on its axis causes Coriolis force.

Coriolis force causes easterly and westerly patterns of air circulation.

Circulating patterns of air drive surface currents in ocean (through friction).

• Northern hemisphere gyres = clockwise.

• Southern hemisphere gyres = counter-clockwise

Gyres move not only heat, but also garbage!