Marine biodiversity Threats & Conservation

What is biodiversity? Variety of life –Species –Genes –Habitats

Three domains of life Bacteria Archaea Eukarya –All present in the ocean –Bacteria, archaea are poorly known—few thousand or tens of thousand of species known –230,000 or so marine plants and animals

Diversity in different ocean zones Pelagic – open ocean, upper 200 meters –Very low biodiversity –Dominated by floating animals in 4 groups, mainly copepods. Only some 2000 species 1-2 mm long May be largest biomass

Ocean biodiversity Benthic habitats much more diverse –Includes coral reefs –Remember: benthic means bottom, not necessarily deep

Value of biodiversity Goods and services This is an IMPORTANT general idea: what goods or services does nature (in this case, the marine environment) provide? Food Oxygen Drugs Carbon storage Weather moderation Coastal protection (mangroves) The goods and services to the left have monetary value What about: –Beauty –Stewardship of nonhuman life –Other?

Marine food webs Primary producers –Bottom of food web –Photosynthesizers –In ocean: tiny cyanobacteria that are responsible for 2/3 of the production (of biomass) –More generally: PHYTOPLANKTON, which means ``floating plants’’

Marine food webs Phytoplankton –Limited by nutrient availability –Nutrients such as iron Iron fertilization as a technique to slow global warming

Marine food webs Next level: ZOOPLANKTON –Floating animals –Grazers Then, various levels of larger grazing animals, culminating in large predators –Tuna, sharks, groupers, cod, etc

Threats Fisheries –Target top predators Compare to terrestrial food webs Climate change –Increasing temperature of sea water –More carbon dioxide  increased acidity CO 2 + H 2 O  carbonic acid

threats Pollution –Most pollutants ultimately enter the oceans Oil Nutrients – carried by rivers to the sea Atmospheric deposition – mercury

Most oil in the sea is from land-based operations –Including dumping oil when changing motor oil

Nutrients: dead zones

Atmospheric deposition: mercury Burning fossil fuels –Especially coal-burning power plants Incinerating municipal wastes –Found in common household products, including fluorescent bulbs, thermometers, batteries

Atmospheric deposition: mercury Mercury enters marine and freshwater systems –Concentration grows up the food chain –BIOACCUMULATION