Introduction to Marine Life

Some Essential Characteristics of Life Made of cells Getting energy Growth and development Reproducing Respond to environment Maintaining homeostasis

Ocean Ecosystem An ecosystem is a level of organization that includes living things and their environment Living things cannot exist without their environment Most of our planet is covered by the ocean or marine ecosystem

Structure and Function of an Ecosystem What the ecosystem is made up of and how it works are linked and influence each other… STRUCTURE Abiotic factors Biotic factors FUNCTION Interactions between living things Cycling

ABIOTIC and BIOTIC FX Physical or non-living parts of the environment that influence living things are called abiotic factors examples: Living factors which influence living things are called biotic factors examples:

Abiotic Factors in the Ocean Inorganic nutrients like: C,N,H,P,S,Fe,Si Motion in the ocean: upwelling, currents, tides Dissolved materials like gases and salts Climate: temperature, light, pressure Variations in time and space

Biotic Factors Characteristics of living things Diversity: Many different types of species Interactions between living things: symbiosis, competition and predation

LAND vs OCEAN Ocean is wetter than land –Materials can be dissolved in ocean water –gametes can be dispersed more easily –Harder for smaller things to move through water Ocean is more vast than land –Harder to find mates and food Ocean is more supportive than land –Body structure will be different than land animals Living in aquatic environment will shape biology and adaptations of marine life

Salinity: Stenohaline (steno-) Organisms withstand only small variation in salinity Typically live in open ocean Euryhaline ( eury- ) Organisms withstand large variation in salinity Typically live in coastal waters, e.g., estuaries

Salinity: Osmoconformers Do not expend energy removing water or salt from their bodies Gain or lose water at a regular rate/ internal salinity similar to seawater Typically stenohaline Osmoregulators Maintain a stable internal osmolarity by homeostasis Marine examples maintain an internal salinity lower than seawater Typically euryhaline

Saltwater vs Freshwater Fish

Marine Fish continued… Need to maintain body water Marine fish are at risk of ‘dehydrating’, and freshwater fish are at risk of having their cells burst from the uptake of too much water

Temperature Ectotherm ( ecto-) Body temp varies with the temp of their environment Can thrive even at higher latitudes by overwintering, migration, burrowing, natural antifreeze Examples: most fish, amphibians, reptiles and most invertebrates

Temperature Endotherm ( endo-) Body temp is produced metabolically ie: breakdown from food In some cases animal needs 5 times the food energy to stay alive as compared to an ectotherm of same weight Examples: All birds and mammals; tuna; skunk cabbage; some insects like butterflies and bees

Temperature Species in warmer seawater tend to be smaller then relatives in colder water More appendages in warmer seawater Tropical organisms grow faster, live shorter, reproduce more often More diversity in warmer seawater Total amount of life is greater in cooler seawater (lots of nutrients)

Temperature Stenothermal –Organisms withstand small variation in temp –Typically live in open ocean Eurythermal –Organisms withstand large variation in temp –Typically live in coastal waters

REPRODUCTION Animals in marine environment have many strategies for “success” Egg production is “costly” and there are tradeoffs for each strategy for reproduction R-strategy….produce many offspring with low probability of survival K strategy… produce less young but heavily invested in offspring so higher chance of survival

More on Reproduction Specific methods of producing offspring… Fission, budding, eggs hatching externally, eggs hatching internally, live births, some marine animals are born in freshwater, some are born on land, etc… Reproducing in water allows for a lot of external reproduction

GROWTH and DEVELOPMENT Life history…cycle from birth to reproduction Animals often look very different in early life history from their adult form Many marine orgs undergo metamorphosis dependent on environmental conditions Larval stages are often food for higher trophic levels

Size in the Ocean As an organism gets larger it’s volume increases faster than it’s surface area. The S/V ratio is maximal at small sizes Small S/V ratios help fight against sinking but are also best for exchanging gases and nutrients

Physical Support Phytoplankton example Must live in the upper water column. Must remain buoyant. How to resist sinking?...take advantage of water’s viscosity. Be small…more specifically, have a small volume but larger surface area…think about an ant with a parachute! Sinking is a bigger problem in warm water because warm water is less viscous.

Staying Afloat Appendages to increase surface area Oil in micro-organisms to increase buoyancy Fewer support structures in cold rather than warm seawater

Physical Support Larger orgs (swimmers) are streamlined Flattened / tapered bodies Would you rather be a Ferrari, or a minivan?

Naturalseasponge.com

Classification of Living Things Taxonomy / Systemactics Every organism has a two part name unique to itself Genus species or Genus species –Prevents confusion if a species is known by many common names There are several ways to classify animals at higher levels of organization

Evolution of Life Evidence supports that first life evolved in the oceans ~3.5 bya –Photosynthesis began 2.5 mya –For 2.3 by all life was single celled –About 1.2 bya more complex mutlicellular life evolved –Life forms have become more diverse –Fossil record reveals patterns of evolution and extinction

Oceans throughout Geologic Time es/663x/public/photos/603_P01_G02w.jpg ?itok=1ZEpu8Ijhttp://ocean.si.edu/sites/default/files/styl es/663x/public/photos/603_P01_G02w.jpg ?itok=1ZEpu8Ij

Kingdoms of Life Classification

Cellular Differences Prokaryotes – Kingdom Moneran / bacteria group –Lack a nucleus and membrane bound organelles Eukaryotes- All other kingdoms –Have a nucleus and membrane bound organelles

Lifestyles of Marine Orgs Planktonic Nekton Benthic

Plankton Most biomass on Earth consists of plankton Phytoplankton –Autotrophic (diatoms, coccolithophores) Zooplankton –Heterotrophic Bacterioplankton –The most abundant photosynthetic organism on earth Half of all the photosynthetic biomass in ocean Virioplankton –Viruses (mostly attack plankton)

Types of Plankton Holoplankton –Entire lives as plankton –Ex. copepod Meroplankton –Part of lives as plankton –Juvenile or larval stages –Ex. Blue crab

interactive.usc.edu/.../archives/2005/08/

Nekton Independent swimmers Ex…fish, marine mammals

Benthos Live on surface of sea floor or buried in sediments Most abundant in shallower water Ex. Marine worms, crabs, lobsters

FOOD WEBS Trophic level… position or feeding level Producers…base of the food web and create sugars from sun’s energy or chemical energy Consumers…eat other living things Food webs are the connection between many food chains in an ecosystem

Marine Food Chain Phytoplankton…single celled plant like orgs (diatoms) Zooplankton…tiny animal life that drift thru the water and graze on plankton (copepod) Secondary consumers…filter feed out zoo and phytoplankton (silverside or clam) Tertiary consumers…predators that feed on smaller fish in level below (bluefish) Apex predators…efficient hunters, opportunistic feeding habits (eat what is available) (tuna, sharks, billfish) Higher level consumers…predators that feed on smaller fish in level below (bluefish or flounder)

10% Rule Higher trophic level orgs…larger in size and fewer in number than those at lower levels. each trophic level transfers 10% of its energy each level supports a smaller total biomass to compensate loss of food value. 90% loss is used for growth, reproduction, repair etc…

What Does 10% Rule Mean? 100,000 lbs of phytoplankton feed 10,000 lbs of copepods, 10,000 lbs copepods feed 1,000 lbs of silversides 1,000 lbs silversides feed 100 lbs of mackerel 100 lbs of mackerel feed 10 lbs of bluefin tuna tuna nourishes only one pound of apex predator

OTHER FOOD ROLES Decomposers… break down food and nutrients left over from predation or in dead orgs or waste Omnivores…feed on consumers and producers Microbial loop…bacteria help make available even smaller nutrients called DOM (dissolved organic matter) that would otherwise be lost

Gas Exchange and Carbon Cycle Oceans absorb and store large amounts of CO 2 –Contain about 50 X the amount found in the atmosphere biological pump -some of the absorbed CO 2 is used in the food web by phytoplankton, or used to make shells and then consumed and pooped out gas is trapped in the deep ocean (sequestered) until brought to surface by currents

Ocean Acidification CO 2 is changed to carbonic acid as it dissolves in seawater –More CO 2 dissolving, more acidic ocean is becoming –30% increase in acidity since IR Marine life that produce calcium carbonate shells are negatively impacted by increasing acidity (coral, clams, mussels, oysters, some algae)

The photos below show what happens to a pteropod’s shell when placed in sea water with pH and carbonate levels projected for the year The shell slowly dissolves after 45 days. Photo credit: Used with permission, National Geographic ImagesNational Geographic Images