Aquatic Ecosystems Biodiversity AP Environmental Science Aquatic Systems

Aquatic Ecosystems & Biodiversity AP Environmental Science

Aquatic Systems • Earths Surface: – 71% Ocean (Marine) – 2. 2% Fresh Water • Total Water – 97% Ocean (Marine) – 3% Fresh Water

Aquatic Ecosystems & Biodiversity NICHES & ORGANISMS

Four Major Types of Organisms in Aquatic Ecosystems • Plankton– Free-floating, weakly swimming, one-celled organisms. – Phytoplankton, Zooplankton, Ultraplankton • Benthos: bottom feeders – Craps, filter-feeders, etc – Upwelling brings this “marine snow” back up to the surface for other fish as well • Necton: fish, turtles, whales • Decomposers: mostly bacteria

Niches

Phytoplankton • Phytoplankton (plant plankton) – Aquatic Ecosystems are mostly dependent on these photosynthetic organisms to support the food web – In oceans, most photosynthetic activity is near coastlines • Nitrogen, phosphorous, other nutrients runoff into the ocean • Ocean currents distribute nutrients and phytoplankton by carrying them away from shore • Description – small drifting plants • Niche – they are producers that support most aquatic food chains • Example – cyanobacteria & many types of algae

Zooplankton • Zooplankton (animal plankton) • Description – herbivores that feed on phytoplankton or other zooplankton • Niche – food stock for larger consumers • Example – krill; small crustaceans

Ultraplankton • Ultraplankton (photosynthetic bacteria) • Extremely small plankton • Responsible for as much as 70% if the primary productivity near the ocean’s surface.

Nekton • Description – larger, strong-swimming consumers • Niche – top consumers in the aquatic ecosystem • Example – fish, turtles, and whales

Benthos • Description – bottom-dwelling creatures • Niche – primary consumers, decomposers • Example – barnacles, oysters, and lobsters

Key Factors that Determine Biodiversity of Organisms in Aquatic Ecosystems • • • Temperature Dissolved Oxygen (DO) Sunlight Availability Nutrient Availability Turbidity – Cloudiness of the water – Can limit photosynthetic activity

Aquatic Ecosystems & Biodiversity MARINE ECOSYSTEMS (OCEAN)

Marine Ecosystems Natural Capital Ecological Services • • Climate moderation CO 2 absorption Nutrient Cycling Waste Treatment Reduce Storm impact Habitat & Nursery areas Biodiversity Scientific Information Economic Services • • • Food Animal & Pet Feed Pharmaceuticals Harbors & Transportation Routes Costal habitats for humans Recreation Employment Oil & Natural Gas Minerals Building materials

Marine Ecosystems • Vertical Stratification – Light/temperature decrease with depth – Photic zone – light reaches (about 20 m) • Littoral – shoreline • Intertidal – are exposed by low tide Continental Shelf

Two Major Life Zones of Oceans Coastal • Interacts with land = affected by human activities • High productivity 10% of all oceans but 90% of all marine species • Plenty of sunlight and nutrients • Estuaries, coastal wetlands, mangroves, barrier islands, sandy shores, coral reefs Continental Shelf

Two Major Life Zones of Oceans Open Ocean • Euphotic Zone: lighted, rich in phytoplankton, low nutrient levels (excpet during upwellings), high levels of DO • Bathyal Zone: dimly lit middle zone, no producers, zooplankton & small fish live here • Abyssal Zone: dark, cold, little DO, filter feeders, hydrothermal vents, low productivity

Marine Ecosystems • Deep Ocean – Relatively low productivity – Around equator, many fish and phytoplankton – Sargasso Sea – blankets of brown algae support many diverse animals – Deep-sea thermal ventschemosynthetic • Tubeworms, mussels, microbes • Thousands of microscopic organisms

Marine Ecosystems • Coral Reefs: – High productivity/diversity • Home to ¼ all marine species – – – Protect shorelines Shelter fish, worms, crustaceans, etc. Shallow warm waters, sunlight Dependent on photosynthetic algae Coral Bleaching: warms waters are killing coral. • 1/3 destroyed by 2006, by 2030 60% expected to be gone

Gray reef shark Sea nettle Green sea turtle Blue tang. Fairy basslet Parrot fish Brittle star Algae Hard corals Sergeant major Banded coral shrimp Phytoplankton Coney Symbiotic algae Zooplankton Blackcap basslet Sponges Moray eel Bacteria Producer to primary consumer Primary to secondary consumer Secondary to higher-level consumer All producers and consumers to decomposers Fig. 8 -12, p. 177

Marine Ecosystems • Mangroves – Trees that grow in salt water – Calm, shallows, tropical coastlines – Stabilize shorelines – Nurseries for fish, shrimp, other commercial species – Clear-cut for timber, make room for fisheries • Mangroves provide protection for these fish they are being removed for. – Reduced catches, falling income

Marine Ecosystems • Estuaries: – Bays where rivers empty into the sea – High productivity/diversity – “dead zones” : excess nutrients stimulate bacteria that uses O 2 needed for other life • Tide-pools: – Depressions in rocky shoreline that flood at high tide, retain water at low tide – Specialized species • Starfish, sea anemone, ect.

Tide Pools Rocky Shore Beach Sea star Hermit crab Shore crab High tide Periwinkle Sea urchin Anemone Mussel Low tide Sculpin Kelp Monterey flatworm Barnacles Sea lettuce Nudibranch Fig. 8 -11 a, p. 176

Marine Ecosystems • Barrier Islands – Low, narrow, sandy island parallel to the coastline – Protect inshore lagoons and salt marshes from storms, waves, tides – Critical in preserving coastlines, estuaries, and wetlands – Human occupation speed up erosion of barrier islands, vulnerable to storms

Barrier Islands Beach flea Barrier Beach Peanut worm Blue crab Tiger beetle Clam Dwarf olive High tide Sandpiper Silversides Low tide White sand macoma Sand dollar Ghost shrimp Mole shrimp Moon snail Fig. 8 -11 b, p. 176

Aquatic Ecology & Biodiversity DEGRADING MARINE ECOSYSTEMS

Degradation of Marine Ecosystems • • • Coastal development Pollution Overfishing Fish trawlers Invasive species Climate change

Invasive Species (HIPPCO) • Displace, cause extinction • Undaria (aka wakame) of native species & disrupt ecosystem services & human economies • Usually enters through • Lionfish ballast waters of ships – Ships still carry them if ballast waters are dumped before entering a port • Consumers promote

Coastal Population Growth (HIPPCO) • ~45% of world’s population lived near or along coastlines • Increased growth = more boats, off-shore construction, oil/natural gas drilling • More collisions with boats & sea animals • Noise pollution • 80% ocean pollution comes from coastal activities

Climate Change (HIPPCO) • Rising Sea-Levels – Destroy coral reefs – Swamp low-lying lands – Drown productive coastal wetlands – Destroy mangroves – Increase acidity = less sound absorption = more noise pollution

Overfishing (HIPPCO) • 80% of some wild fish have • Overfishing leads to: been depleted in the last 10 – Most often commercial extinction (no longer -15 years profitable) • Fishery: concentration of – Destroys the marine food an aquatic species suitable chain for commercial harvesting – Allows for invasive species to in a given area take over • Fishprint: an area of ocean needed to sustain the fish consumption of the average person, nation, or world. – Global Fishprint is unstainable!

Industrial Fishing • Trawler fishing – Cod, flounder, shrimp, scallops – Dragging funnel shaped net along the ocean bottom – Scrapes & destroys ocean floor habitats • Purse-seine fishing – Tuna, mackerel, anchovies, herring – Kills other species (like dolphins) not being fished

Industrial Fishing • Long-lining – Swordfish, tuna, sharks, halibut, cod – Use lines up to 100 km long with 1000 s of baited hooks – Kill endangered sea turtles, dolphins, seabirds • Drift-net fishing – Huge nets that hang up to 15 m deep – Leads to overfishing of desired species and traps/kills many unwanted fish (bycatch) along with sea mammals, turtles, birds – 1/3 of all fishing weight is bycatch that is thrown overboard dead or dying

Fish farming in cage Trawler fishing Spotter airplane Sonar Purse-seine fishing Drift-net fishing Long line fishing Float Buoy lines with hooks Deep sea aquaculture cage Fish caught by gills Stepped Art Fig. 11 -8, p. 259

Aquatic Ecosystems & Biodiversity PROTECTING MARINE BIODIVERSITY

Difficulties in Protecting Marine Biodiversity • Ecological Footprint & Fishprint expanding so rapidly, it is hard to monitor their impacts • Most damage is not visible to most people • Most people view the ocean as an inexhaustible resource • Most of the world’s ocean lies outside of a country’s jurisdiction. – Open-access source = tragedy of the commons

Laws & Treaties • 1975 Convention on International Trade in Endangered Species (CITES) • 1979 Global Treaty on Migratory Species • US Marine Mammal Protection Act of 1972 • US Whale Conservation & Preservation Act of 1976 • US Endangered Species Act of 1973 • 1995 International Convention on Biological Diversity

International Whaling Commission Moratorium on Commercial Whaling • Japan hunts and kills ~900 whales a year – On record for scientific purposes – Whale meat sold in restaurants and stores • Norway openly defies the moratorium and kills ~500 -800 whales a year • Iceland kills ~150 whales a year • Traditional in their countries

Other Protections • Educating about Economic Incentives – Sea turtles are worth more alive than dead (ecotourism) – Whale watching • Quotas & Governmental Permissions • Establishing Marine Protected Areas – 4000 worldwide – Only partially protected from human activity • Establishing a global network of marine reserves – Declared off-limits to any human activity to allow recovery

Aquatic Ecosystems & Biodiversity MANAGING FISHERIES

Solutions Managing Fisheries Fishery Regulations Set low catch limits Improve monitoring and enforcement Economic Approaches Reduce or eliminate fishing subsidies Certify sustainable fisheries Protect Areas Establish no-fishing areas Establish more marine protected areas Consumer Information Label sustainably harvested fish Publicize overfished and threatened species Bycatch Use nets that allow escape of smaller fish Use net escape devices for seabirds and sea turtles Aquaculture Restrict coastal locations of fish farms Improve pollution control Nonnative Invasions Kill or filter organisms from ship ballast water Dump ballast water at sea and replace with deep-sea water Fig. 11 -11, p. 267

Aquatic Ecosystems & Biodiversity FRESHWATER ECOSYSTEMS

Why Are Freshwater Ecosystems Important? • Freshwater ecosystems provide major ecological and economic services, and are irreplaceable reservoirs of biodiversity.

Water Stands in Some Freshwater Systems and Flows in Others • Standing (lentic) bodies of freshwater – Lakes – Ponds – Inland wetlands • Flowing (lotic) systems of freshwater – Streams – Rivers

Freshwater Ecosystems Vertical Stratification • Four zones based on depth and distance from shore 1. Littoral zone • • • 2. Near shore where rooted plants grow High biodiversity Turtles, frogs, crayfish, some fish Limnetic zone • • • Open, sunlight area away from shore Main photosynthetic zone Some larger fish

Freshwater Ecosystems Vertical Stratification 3. Profundal zone • • • Deep water too dark for photosynthesis Low oxygen levels Some fish 4. Benthic zone • • Decomposers Detritus feeders Some fish Nourished primarily by dead matter

Lakes • Some lakes have more nutrients than others. • Oligotrophic lakes – Low levels of nutrients and low NPP – Very clear water • Eutrophic lakes – High levels of nutrients and high NPP – Murky water with high turbidity • Mesotrophic lakes • Cultural eutrophication of lakes from human input of nutrients

Eutrophication • The Effect of Nutrient Enrichment on a Lake • Eutrophication: Changes that take place after a water systems receives excess nutrients (usually nitrates & phosphates) from runoff. Fig. 8 -17, p. 182

Freshwater Ecosystems • Lakes – Vertical zones • Open water: plankton, microscopic plants, animals, & protists, water striders, mosquitoes • Water column – variety of fish • Benthos: bottom, snails, worms, fish, other organisms • Littoral: plants – Conditions that affect lake productivity • Nutrient availability, nitrates, phosphates • Suspended matter, silt, affects depth of light • Depth • Temperature • Currents • Bottom: muddy, sandy, rocky floor • Connections to other ecosystems

Freshwater Ecosystems • Lakes

Freshwater Streams and Rivers Carry Water from the Mountains to the Oceans • Surface water – Precipitation that does not sink into the ground or evaporate. • Runoff – Surface water that flows into streams • Watershed, drainage basin – Area of land that delivers runoff into a stream • Three aquatic life zones – Source zone – Transition zone – Floodplain zone

Streams & Rivers

Streams & Rivers • Source Zone – – Usually shallow, cold, clear, fast flowing streams Lack nutrients & producers Trout, algae, mosses High DO • Transition Zone – – Merging of small streams into wider, deeper, warmer streams Higher turbidity (not as clear) Less DO than source zone streams Bass • Floodplain Zone – – Streams join wider, deeper, slower moving rivers Higher temperatures, Less DO Rooted aquatic plants, algae, cyanobacteria, carp, catfish Deltas area where the mouth of a river dumps into the ocean (coastal wetlands & estuaries)

Streams & Rivers

Rivers

Freshwater Ecosystems • Wetlands – Shallows, land surface that is submerged part of the year – Rich biodiversity – Essential for breeding and migrating birds • 5% of US is wetlands, but 1/3 of endangered species call the wetlands home – Retain storm water, control flooding, filter/purify urban and farm runoff – Swamps- wetlands w/ trees – Marshes- wetlands w/o trees – Bogs – areas of saturated ground (usually composed of peat) – Fens – bogs fed by groundwater, mineral rich, specially adapted plant species – Swamps & Marshes- high productivity – Bogs & Fens – low productivity

Freshwater Ecosystems

Human Activities Are Disrupting and Degrading Freshwater Systems • Impact of dams and canals on rivers • Impact of flood control levees and dikes along rivers • Impact of pollutants from cities and farms on streams, rivers, and lakes • Impact of drained wetlands

Aquatic Ecosystems & Biodiversity PROTECTING FRESHWATER ECOSYSTEMS

We Can Preserve and Restore Wetlands • Laws for protection – Zoning laws steer development away from wetlands – In U. S. , need federal permit to fill wetlands greater than 3 acres • Mitigation banking – Can destroy wetland if create one of equal area – Ecologists argue this as a last resort

Human-Created Wetland in Florida Fig. 11 -12, p. 268

Freshwater Ecosystems Are under Major Threats • • Think: HIPPCO 40% of world’s rivers are dammed Many freshwater wetlands destroyed Invasive species Threatened species Overfishing Human population pressures

We Can Protect Freshwater Ecosystems by Protecting Watersheds • Freshwater ecosystems protected through – Laws – Economic incentives – Restoration efforts • Wild rivers and scenic rivers – 1968 National Wild and Scenic Rivers Act