Marine Community Ecology Day 1

Ecologists call relationships between species in a community interspecific interactions Examples are competition, predation, herbivory, and… symbiosis (parasitism, mutualism, and commensalism)

Symbiosis a relationship where two or more species live in direct and intimate contact with one another

1. Mutualism (+/+) an interspecific interaction that benefits both species It may be one of 2 types: * Obligate: one species cannot survive without the other * Facultative: both species can survive alone

Ex. Coral and zooxanthellae (Obligate)

Ex. Cleaner wrasse and larger fish and sharks (facultative)

2. Commensalism (+/0) One species benefits while the other is unaffected Ex. Barnacles on baleen whales

Ex. Remora and tiger shark

Ex. Clown fish and anemone

Parasitism (+/–) one organism, the parasite, derives nourishment from another organism, its host, which is harmed Parasites that live within the body of their host are called endoparasites parasites that live on the external surface of a host are ectoparasites

This is a tapeworm that is often found in the small intestine of minke and sei whales but can also infect dogs and people who eat uncooked infected whale meat or fish (which might carry the larval stages of many parasites.) The eggs of Diplogonoporus, shed in the feces of the whale, are eaten and hatch within small crustaceans called copepods, which are then eaten by small fish, later sieved out of the water by baleen whales such as the minke.

Ichthyophthirius multifiliis

Ex. The Anisakis worm The Most Extreme - Odd Couples number 10 and 9 - YouTube

Marine Community Ecology Day 2

Ecological Niche The total of a species’ use of biotic and abiotic resources an organism’s ecological role Ecologically similar species can coexist in a community if there are one or more significant differences in their niches

Interspecific competition (–/–) occurs when species compete for a resource in short supply Ex. Mussels competing for space

Predation (+/– interaction) refers to interaction where one species, the predator, kills and eats the prey

Adaptations for prey survival Cryptic Coloration (camouflage) ex. flounder

aposematic coloration (warning coloration) The Most Extreme - Venom - YouTube

Batesian mimicry (harmless organism mimics the coloration of another species) World's Most Intelligent Animal - Mimic Octopus - YouTube Ex. Eibli Mimic Tang and an Eibli Angelfish

Herbivory (+/–) refers to an interaction in which an herbivore eats parts of a plant or alga ex. Manatee and seaweed

Injuries due to boat propellers

Ex. Sea urchin feeding on kelp

Dominant species those that are most abundant or have the highest biomass Biomass is the total mass of all individuals in an area exert powerful control over the occurrence and distribution of other species

Ex. phytoplankton

DOMINANT ORGANISMS

Keystone species exert strong control on the health of a community by the ecological roles they play In contrast to dominant species, they are not necessarily abundant in a community VIDEO

Ex. Sea otters

Number of species present 1963 ’64 ’65 ’66 ’67 ’68 ’69 ’70 ’71 ’72 ’73 RESULTS With Pisaster (control) 20 15 10 5 Without Pisaster (experimental)

Abyssal plian, Island, Trench, seamount, continental shelf, slope,