Photic Pelagic Waters

I. Location A. From surface to 200m (average) B. Where photosynthesis takes place

II. Environmental Characteristics A. Sunlight 1. Plenty of sunlight 2. Where most oxygen for planet is produced 3. Wide variety of photosynthetic organisms

B. T  1. Much warmer than deep sea (for the most part) 2. Changes from day to day (sometimes within the day) 3. Has seasonal changes (warm during summer, cooler during winter) 4. Varies from place to place

C. Pressure 1. Upper photic – not much 2. Lower photic – bit more, but nothing like the deep sea D. O 2 - #1 producers of oxygen, so plenty E. Food – Not a problem; more food than anywhere else

F. Habitat 1. Surface water is in constant motion – waves, tides and currents 2. Really no place to hide or rest – open water 3. Can’t rest for long – will be eaten or starve

III. Importance of Photic Waters A. All primary productivity for ocean occurs here B. Start of the basis of the marine food chain C. Place where humans like D. Richest part of the ocean

IV. Types of Organisms A. Plankton – organisms at the mercy of the ocean; drifters 1. Phytoplankton – planktonic plants plants at the mercy of the ocean a) Basis of the marine food chain b) Photosynthetic - #1 producers of oxygen c) Most microscopic – diatoms, dinoflagellates; Protistas Diatoms dinoflagellates

d) Seaweed & kelp – true plants at mercy of ocean e) Without phytoplankton – NO LIFE f) Produce more oxygen than anything else Where did the phytoplankton go!!?

2. Zooplankton – planktonic “animals” a) Most microscopic – copepods, larvae of many invertebrates (crab, shrimp) b) Some mega plankton – jellyfish, sunfish (one of largest fish in sea) c) Second step in the marine food chain Mola mola

B. Nekton – directed swimmers, NOT at the mercy of the ocean 1. Includes all vertebrae marine life, fish, adult invertebrates 2. Must have special adaptations to live in “open” waters 3. Most nekton “hydrodynamic” – streamlined to move through water easily, fins retractable, eyes flushed with head, powerful tails

4. There is more nekton then any other type of animals (except insects)

V. Two Very Important Phytoplankton and One Zooplankton A. Diatoms – unicellular, microscopic algae (phytoplankton) 1. Looks like a “petri dish”, usually a golden-brown color 2. No means of locomotion 3. Made of silica -> makes siliceous ooze

4. Feeds over half the marine life 5. Millions upon millions throughout every ocean 6. Probably most important organism on this planet

B. Dinoflagellates – unicellular, microscopic algae; phytoplankton 1. Has locomotion – flagella -> “whip like” projection

2. Causes red tides - a massive killing of marine life a) Dinoflagellates suddenly multiply in large numbers – millions & millions b) They have a toxin that poison and suffocates marine life c) In such large numbers, the dinoflagellates tint the water red -> red tide

d) DO NOT EAT OYSTERS, FISH, OR CLAMS DURING A RED TIDE!!! e) Have been known to harm humans (Not attacked, but swallowed)

C. Copepods – microscopic, shrimp like zooplankton 1. Feed on phytoplankton 2. Second step in marine food chain 3. Filter feeders 4. Most have bioluminescence 5. Have adaptations to keep from sinking into “Death Zone”, below the light

VI. Adaptations of Photic Water Organisms A. Main goal is to stay in the photic zone – fall below will die (T , Pressure, no food) B. Many have “projections” – fins, hair, spines, etc 1) Increases surface volume of “body” 2) Slows sinking rate

C. Body shape 1) Most are flat – easier to stay afloat 2) Streamlined – move through water fast; 3) Extra fat – blubber -> help larger animals stay afloat 4) “Air” bladder – many fish, allows them to stay “suspended”

D. Coloring 1) Counter-shaded -> dark on top, light on bottom, blends in with environment 2) Striping – dark, light banded – blends with wave action 3) Plankton – usually brownish or clear (hard to see)

4) Some brightly colored – “coral reef” blending 5) Nekton – generally silver, gray E. Speed 1. Nekton – usually very fast, if not will be eaten or starve 2. Plankton don’t have to worry

F. Defense 1. Being big or very small 2. “Swim in schools” 3. Being fast 4. Coloring - hard to see

VII. The Benthos Organisms A. Benthos – organisms that live in or on the bottom of the ocean B. Includes – crabs, clams, sea stars, barnacles, snails, octopus, some fish, coral, etc…

C. Three Types 1) Epifauna – live on top of the ocean floor 2) Infauna – lives in or burrow into the sediments of the ocean floor 3) Sessile – permanently attached; like barnacles

D. Most benthos on continental shelf E. Harsh environment 1) Constant changes in salinity levels 2) Constant and heavy waves, currents & tide action 3) Constant change in water T  4) “Home” constantly moving (unless on rocks)

F. Adaptations 1) Excellent burrowers – can dig in sediments very fast 2) Usually have a “shell” for protection (keep from getting crushed – waves, seds) 3) Cryptic coloring – can change or “patterned” after sediments

4) Some have great “stick ‘um” power – cling to rocks, etc,, 5) Special feeding lots of food in this area; mostly tiny “particles” a) filter feeders -> “rake in” food particles (usually with antenna or “hands”)

b) siphon feeders -> “siphon” in water with food particles c) detritus feeders – feed on small particles of decaying matter

VIII. Miscellaneous A. The photic zone is a vast area B. Includes many species of organisms C. Variety of adaptations, colors, sizes, etc… D. 99% of all studies in the ocean are in the photic zone E. Still many unanswered questions F. Without the photic zone, there would be NO LIFE!

IX. Importance of the photic waters A. Start of food chain 1. primary productivity – energy that comes from photosynthesis 2. #1 producers of photosynthesis – phytoplankton 3. 20% of the phyto sink below the photic zone & die

4. the sinking of dead organisms is called detritus 5. 90% of food for benthic comes from detritus 6. about 95% of all marine “food” begins in the photic zone 7. Without phytoplankton = no life

B. Nutrients not found readily in photic zone 1. Nutrients needed to help go through photosynthesis 2. most nutrients found below photic zone 3. need a nice mixing of waters a. upwellings – a current that brings nutrients from the deep to the surface

b. winter mixing – surface waters become colder & sink 1) this forces nutrients to surface 2) excellent winter mixing in Gulf of Mexico – very productive 3) the tropics & the polar regions – not very good mixing leads to poor primary productivity – but clear waters

C. Factors that affect primary productivity 1. Types of organisms – more phytoplankton = more “food” 2. Sunlight – needed for photosynthesis 3. T  & seasons – affects amount of nutrients 4. Amount of nutrients – can’t live on sunshine alone