Presentation on theme: "Threats, Human Benefits, Food Web"— Presentation transcript:
1 Threats, Human Benefits, Food Web Coral ReefsThreats, Human Benefits, Food Web
2 What are corals? Plants or animals? Plants make their own food Animals depend on outside sources for their nutritional requirements
3 They’re animals!Coral animals take advantage of both forms of nutrition by hosting plant-like algae (protists) in their tissues.The majority of the coral’s energy needs are provided by tiny algae called zooxanthellaeZooxanthellae live inside the coral and produce food using the sun’s energy from carbon dioxide and water
4 Toxicity Testing Lab Objectives Measure the effect of various toxic materials on zooplankton.Determine the LD50 (Lethal Dose 50%) for a variety of toxic materials.
5 Lab cont.IntroductionWe handle many materials daily that are toxic. We are often unaware of the degree to which they are toxic. In this laboratory we will look at water solutions of several household materials and determine their toxicity to zooplankton.Measuring toxicity requires a standard method of comparison. A typical method is to determine the concentration of a toxic material that causes 50% mortality in a population of test animals. This is called an LD50 (Lethal Dose 50%) test of toxicity. For a variety of reasons, different animals respond differently to the same toxin. Some animals may be very sensitive to a toxin, whereas others are relatively resistant to its effects. Because species of animals vary, it is important to understand that what is toxic to zooplankton may not necessarily be toxic to other kinds of animals to the same extent.Many household items that we deal with on a regular basis are toxic materials, but we don’t usually think of them as being toxic. It should be instructive to examine several such materials to determine their toxicity.
6 Lab cont. Directions Obtain 5 petri dishes. Label these dishes as follows:100%10%1%0.1%0% (control)
7 Zooxanthellae (zoo-zan-thel-a) Symbiotic relationshipClose relationship between two or more organismsMutualism: benefiting both partnersCorals animals and zooxanthellaeSensitive to high light, variations in the concentrations of salt and especially to high temperaturesUse sunlight for photosynthesisIf sea temperature is too high, zooxanthellae leave, causing the corals to appear brilliant white
8 What is coral bleaching? Bleaching is what happens to corals when sea temperatures are too warm for zooxanthellae to liveZooxanthellae gives coral it’s color, when there is more zooxanthellae, the corals are green/brown
10 Coral Reef Food WebZooxanthellae provide corals with vital nutrients produced through photosynthesisPlant life in the sea is composed of microscopic planktonic algae that comprise the base of the entire marine food chainThe wealth of plant life supports quantities of tiny drifting animals (zooplankton) which feel upon drifting plants, and are ultimately swept across coral reefsCoral polyps feed on zooplankton suspended in the flow of sea waterZooplankton is a substantial part of the coral reef food chain
11 Major threats to coral reefs NaturalHurricanesTyphoonsEl NinoCoral-eating organismsDiseasesOcean AcidificationHumanOver-fishingCoastal developmentSewage and other pollutionRising global temperaturesCarless tourism
12 Over-fishingFishing selectively takes larger, predatory fish off the reef causing explosions of smaller herbivorous fishWhen larger fish become scarce, the herbivorous fish are then targeted by fishermenWithout herbivores, seaweeds can overgrow the corals and smother themDestructive fishing practices include using cyanide to stun fish for capture for the marine aquarium and live fish trades and blast fishing to kill fish for foodFishing methods are not species-specific, so many organisms are killed in the process and habitats that took thousands of years to build are destroyed
14 Coastal DevelopmentCoastal construction often removes mangroves and seagrass beds, which takes away the sediment barrierExcess sediments cover corals, blocking light necessary for their symbiotic zooxanthellaeUnder natural conditions, corals are able to out-compete seaweeds because of the low nutrient content in tropical watersWhen outside nutrients are added, faster growing seaweeds can take over and smother corals
15 Sewage and other pollution Adds unnatural and potentially harmful substances to the reef systems including nutrients, pathogens and trashImplicated in the apparent surge in coral diseases, especially in the CaribbeanGarbage pollutionAir pollutionSewage pollution
16 Rising global temperatures One of the most global threats to coral reef ecosystemsWhat causes global temperatures to rise?Burning of fossil fuelsChanges in land useReduction in forest cover
17 Why Care about Coral Reefs? Healthy Coral Reefs = A Healthy WorldSupport 25% of all marine lifeProvide habitat, income, food, protection, medicineAnimals that live nowhere elseHome to more than 4,000 species of fish, 700 species of coral and thousands of other plant and animal life.Scientists estimate that, in total, more than one million species of plants and animals are associated with coral reef ecosystemsMillions of humans depend on coral reefsCoral reefs provide economic goods and ecosystem services worth about $375 billion each yearCoral reefs protect the beaches
18 Protect 109 countries’ coastlines Coral reefs save lives Several important drugs have already been developed from chemicals found in coral reef organismsCardiovascular diseaseUlcersLeukemiaSkin cancerMore than half of all new cancer drug research focus on marine organisms
19 Global Climate Change and Our Life Styles How to reduce greenhouse gas emissions:Conserve energyBuy a fuel-efficient car and drive less oftenReduce, re-use and recyclePlant treesReduce water useChoose sustainable seafoodEducate yourself!
20 Get the Facts!Coral reefs are in crisis, dying at an alarming rate worldwideAn estimated 25% of coral reefs already disappeared and an estimated two-thirds of all oral reefs are at risk todayAn estimated 88% of the reefs in Southeast Asia, the most species rich reefs on earth, are at riskSince 1975, more than 90% of the reefs in the Florida Keys have lost their living coral coverThe most important fact:There are solutions to this crisis.