MSC Notes Exam 3
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Date Created: 12/06/14
Msc Notes exam 3 Benthic communities Unlike pelagic habitats benthic habitats involve characteristics of both water column and underlying sediments Benthos occurs from the beach to the deepest trenches Many have pelagic larval phase Deeper the community the least amount of animals Littoral zone between the mean low tide and mean high tide called splash or spray zone light and nutrients are not usually limiting factors however tides and waves bring additional challenges depth it covers has to do with gradient of coast In the nearshore or littoral zones light and nutrients are not usually limiting factors However tides and waves bring additional challenges These include extremes in temperature and salinity along with desiccation A Supralittoral B Littoral intertidal zone transition zone to terrestrial depth depends on tidal range narrow zone above normal high temp extremes receives full tide sunlight splash or spray zone altemating cycles of ooding temp extremes and sunlight and dessication some inverts and algae thrive organisms must be tolerate of extremes Rocky Intertidal zone the intertidal zone area between high and low tides all the organisms are impacted by salt and waves high productivity and biodiversity Organisms must be able to withstand desiccation wave shock drastic change in temp and salinity sessile organisms must have strong adhesive These organisms deal with these factors in different way motile animals crawl under rocks or overhang for shelter sessile organisms hang on tightly on rocks and often have low profiles to reduce wave impact and tough shells and tides Nutrition in Coastal ecosystems Autotrophic algae living in photic zone and seagrass beds and benthic algae Seaweed cells aggregated together not truly multicellular attach to rock Benthic herbivores grazers seek out primary producers as food have to anchor themselves some actively eat Suspension feeders most are like these use appendages to strain particulate food matter from the water Filter feeders draw water in through siphon filter out food particles and expel water lots of mollusks Deposit feeders process mud removing food particles Sand dollars low through sediment food particles stick to their mucous coating and are moved towards the mouth by cilia Rocky Shoes Zonation what controls distribution of organisms different organisms occur in different strata rapidly changing salinity temp Supralittoral zone Mean high SPrir18 tide Mean high neap tide C o 395 Midlittoral Mean tide Zone 3 0 Mean low neap tide Mean low spring tide lnfralittoral zone b CONTROLS ON VERTICAL ZONATION the further up thg line thg more stressors the more biological factors come into play Zonation results from Preferential larval settlement and adult movement Larvae of sessile animals settle at height suitable for adults Mobile animals adjust by reponding to light gravity and moisture Different physiological tolerance species higher in intertidal generally more tolerant of desiccation reduced feeding hypoxia and extreme temperature swings Biological interactions such as competition and predation Rocky shores are space limited species capable of overgrowing or undercutting others may dominate Marine predators are limited by tidal cycle usually limits predation to lower part Adaptation to heat stress body size and body shape both in uence the degree of heat stress and desiccation morphology of shell bumps and colors re ect more heat Adaptation to Hypoxia reduction of metabolic rates blood pigments with higher 02 af nity air breathing 9 Waves pressure also impacts the distribution of intertidal organisms l Abrasion particles in suspension or oating debris scrape delicate structures as do oating objects 2 Pressure hydrostatic pressure of a breaking wave could break or damage structures 3 Pressure Drag directional force of water movement may rip apart support structures or dislodge holdfasts water on top of organisms produce lots of pressure Competition for space 2 species of barnacles one genus tends to be higher up on the rocks the other is much lower however there is a zone of overlapcompetition larger one dominates deeper smaller one is above Nutrients few predators makes a great habitat for juveniles Oyster reefs mud ats and seagrass meadows Seagrasses Seagrasses are owering plants Angiosperms that grow entirely underwater They may tolerate or require various concentrations of salt Primary productivity in seagrass beds is among the highest measured 500 4000 g Cm2year Seagrasses provide important habitat for marine species shrimp scallops fishes Seagrasses stabilize sediment High nutrients in soil Trap sediment stabilize area No real predators manatees and turtles Die and become food very important source of nutrients salt marshes are replaced by mangroves in tropics Salt marsh food web 9 driven by detritus supports most organisms As with other estuarine food webs most of the primary production of salt marshes enters the marine environment as detritus The detritus supports large numbers of bacteria which in turn are food for numerous organisms that channel the nutrients to higherorder consumers Mangrove wetlands Habitat and nesting sites for many species of birds Nursery for young fish and invertebrates Lots of hiding spots Rich source of nutrients for many organisms Once again its through detritus of mangroves that support organisms Mangrove Food Web V sunlight 39 V humans C A birds shags herons herbivorous insects A yelloweyed mullet 39 smelt ytoplankton 39 with tidal ow A 200 lter feedegrs p plankton S quot U molluscs 9 I crustaceans rainfall runoff nutrients large predator sh kahawai eels large yellowbelly ounder Sediments Flood Ebb Sediments Larvae Detritus Adults 39 I Nutrients Phytoplankton Larvae Reefs shallow parts of sea oor lots of different types of reefs not just coral reefs Ivory tree coral Oculina varicosa NORTHING 520300 520400 520900 lJ9L Shallow rid spurs OLVVLL 09011 0 lELL O9Zll SNILSVEI OLZLL 091U OHU Deeper grooves OSQU GLQLL SCALE I 139 3039 IIIEIIIEIIIE3IIIE3 0 10 20 30 40 50 80 70 80 30 DEPTH COLOR SCALE USN 7700 77310 77010 520300 520650 IiFiTi1Il3 Does coral morphology differ on a reef Reef crest shallowest large branching corals high wave energy high light Elkhorn coral A palmata Staghorn coral A cervicomis 520300 520350 520400 520450 520500 520550 520100 520750 520000 520050 5205000 Fore reef deeper corals round or plate morphology the coral shape is response to light needs of zooxanthalle Deeper coral can have a moundlike or platelike shape to maximize light capture for zooxanthallae Montastrea Spp Agrarcia spp reefs north of Dry Tortugas often first to colonize in damaged habitats occur at deep depths platelike morphology light limited there Pulley ridge may be the deepest reef in US waters Trophic relationships in coral communities Who s at home corals hard amp soft sponges 76980 ges or So 25 to 30 is supported by continuous subsidy bailouts Overfishing occurs because the sheries are bailed out supported by subsidies economic value is 3 times the total value How do we fix fisheries 1 Better Management Methods of Control Input controls include Limits on the number of fishersboats 0 Gear restrictions Minimum and maximum size limits Closed seasons Closed areas Output controls include Total allowable catches TAC s 0 Bag limits Individual transferable quota ITQ s Theres necessary information that we need to know in order to make a educated decision Necessary information 1 Stock size current and historical Reproductive rate Growth rate Age of sexual maturity Age structure Migratory Natural mortality Species interactions OOlOUIgtUJlJ We also need to completely understand the problems Problems 1 Fish move 2 We can t see them 3 Policy Enforcement The MagnusonStevens Fisheries Act First enacted in 1976 and then reenacted in 1996 and 2006 Gives the federal government authority to manage fisheries in cooperation with regional fisheries councils Claimed the area between 3 and 200 miles offshore as the Exclusive Economic Zone The Magnuson Conservation Act of 1976 Designed to eliminate foreign fishing Designed to restore and conserve fish 2 Less Destructive Fishing Hook and line shing and direct capture are probably the most selective fishing techniques and therefore easiest to manage Larger factory ships and trawlers operate in af uent nations and are highly destructive Smaller scale yet pervasive shing occurs in developing countries in areas of abject poverty Examples Turtle exclusion devices TEDs turtles can escape a net that traps all the other smaller organisms like shrimp that its supposed to catch Bycatch reduction devices BRDs 1 Larger mesh sizes 2 Modification of hooks 3 Escape routes 4 Separation tanks 5 Noise devices Implementation is a possible reason behind the perceived decrease from a 103 to a 46 discard to catch ratio in the Gulf of Mexico since 1994 3 Fish Farming Humans realized long ago that farming was more efficient than hunting and gathering Positives 1 Know population parameters 2 No bycatch 3 Minimal fishing effort 4 Ideal growth rates Negatives 1 Habitat destruction 2 Invasive species 3 Disease 4 Eutrophication 5 Efficiency occurs mainly in East Asia China there is a good amount of fish farms in the US 4 Marine Protected Areas MPAs Uniform MultipleUse Many state and national parks Zoned multipleuse national parks and marine sanctuaries Zoned multipleuse with notake areas rare but some marine sanctuaries and national parks Notake rare but often in federal marine reserves for the protection of endangered species No impact No access Within Park 1 increase fish stocks sizes reproduction 2 preserve biodiversity 3 increase nonconsumptive value 4 provide baseline for scientific research Outside Park 9 poorly studied time is an issue 1 Spillover 2 Increase market value older larger individuals found more in Paci c pretty much all salmon are like this you can tell the difference from aquaculture salmon and wild caught by their color 2 Crustaceans especially shrimp 3 Bivalves muscles clams most prevalent is oyster 4 Seaweed 1 fish from aquaculture Cyprinids carp mostly raised in shallow ponds Other Miscellaneous Marine Mollusks Clams Scallos and Pectens Mussels Shrimps Prawns Marine Fish Salmons and Trouts Miscellaneous Freshwater Fish most aquaculture practiced globally is just small ponds like carp ponds 2 is oysters maj ority of aquaculture is freshwater but it is marine aquaculture that gets all the press lots of debate if we should do aquaculture l fishmeal use fake food takes a lot of energy to make it look at how much feed you put in to biomass out there is more fishmeal than fish out if you look at appropriation of marine primary production properly managed marine aquaculture has the potential to be a more efficient system for producing fish than fishing 2 pollution causes terrible land erosion freshwater ponds with waste and unconsumed food too much waste ponds turn anoxic or hypoxic induce dino agellate growth algal blooms theres an idea to go offshore deep water waste does not make such an impact What is a wave A wave is an undulating disturbance that moves across the sea surface Waves are complicated phenomena when a wave travels it propagates energy but there is no real transfer of mass Has circularorbital pattern Waves form and dissipate as a result of the following forces Disturbing forces and Restoring Forces The most common disturbing force is energy transferred to the sea surface by the wind but earthquakes landslides and volcanism can trigger large tsunamis Japanese harbor wave The restoring force for small capillary waves is cohesion ie the property that allows water molecules to stick to each other by hydrogen bonding For larger waves gravity serves as the primary restoring force In all cases waves contain energy which is not present at equilibrium Ocean Waves are extremely persistent as well as ubiquitous Waves transport energy across vast distances entire ocean basins Waves play an important role in airsea interactions for instance in how carbon dioxide gets from the atmosphere into the ocean or how hurricanes gain energy from the ocean a little bit of oil can calm waters oil on troubled waters The Anatomy of an Ocean Wave a sinusoid o Crest o Trough 0 Wave height crest to trough distance 0 Wave amplitude o Wavelength 0 Wave period and frequency ie Wavelength Tu T 0 0 Crest l 0 T Height p P P of Distance 7 or time Trough a WAVE PARAM ETERS Wave period the time it takes for one complete wavelength to pass a fixed point Wave period is used to classzfjz waves Capillary waves periods lt 1 10 second or wl lt 173 cm 0 Chop periods of l second eg Biscayne Bay 0 Swells periods of 10 seconds open ocean waves at shore Tsunamis periods of minutes to l0 s of minutes Direction of wave motion water depth 2 wavelength a DEEPWATER WAVE Because of variable wind intensity and duration e g during a storm you often get lots of different waves formed with different wavelengths and periods Wave trains Fetch gti Dispersion 5 3 3 W V ii l W in Seas Ocean swell Wave Pro le a DEEPWATER WAVE TRANSFORMATIONS As Waves move out you get Sorting or Dispersion as faster waves moves out ahead of others Wave interactions When wave trains meet they tend to interact and the crests and troughs may cancel or reinforce each other This can be hard to predict Extreme rogue or freak waves are usually defined as unlikely events based on some probability distribution Rogue waves and episodic waves Generation of rogue waves is not well understood Land falling storm right side Landfallmg Storm Right Side Strongest Winds Storm 8 rqe 39ea e39 W quot3 F away rquot1ly 3 Resonance ampli cation may occur if period of basin is close to period of natural forcing Tsunami Sometimes incorrectly called tidal waves Better term is seismic sea wave Wavelengths as much as 100200 km Since the average ocean depth is 4 km tsunamis behave as shallow water waves Hence their speed depends on the water depth and can be as high as 760 kmhr Periods range from 8 to 30 minutes Tides Tsunamis are usually triggered by earthquakes They are particularly common in the Pacific because of the abundance of plate boundaries Tsunamis can also be created by large sea oor slumps or volcanic island by trenches A ship in the open ocean may never even notice a tsunami passing by This is because the wave height is lost over the very long wavelength As a tsunami comes ashore the wave is compressed into a smaller volume and then builds steeply and breaks It thus behaves like any other shallow water wave just much bigger Wave heights of tsunamis when they come ashore average 1020 m but can reach 35 m or more If crest arrives first get big wave If trough arrives first get rapid drop in sea level Particularly common in Pacific A tide is a periodic variation of the sea surface height produced and affected by Gravitational pull of the Sun and Moon Rotation of the Earth Three Types of Tidal Patterns Diurnal One high and one low daily Semidiurnal One high and one low every 12 hours with nearly equal highs and lows Semidiurnal Mixed Two tidal cycles per day but uneven highs and lows Occurs where get combination of diurnal and semidiurnal patterns Rising tide ood tide Falling tide ebb tide How do Tides arise First let s consider the Earth M00n system There is a net attraction toward the moon due to the effect of gravity on the water facing the moon a GRAVITATIONAL FORCE I There is also a net outward centrifugal acceleration on the opposite face of the Earth Bulge of water X1 4 to Balance point T 39 or center of mass of the earthmoon system b CENTRIFUGAL FORCE I These forces are equal and opposite to maintain the overall equilibrium I Note that there is both latitudinal and longitudinal variation latitudinal due to shape of bulge longitudinal due to Earth rotation First quarter New moon 1 Water envelope c b SPRING TIDES NEAP TIDES Highest tidal range Smallest tidal range Crests and trough reinforce each other Crests and trough cancel each other out Spring tides highest tidal ranges the earth s axis is slightly tipped the moon is straight up so the bulge is asymmetrically displaced l E 6 5 North Pole 39 0 I day To Time gt p T Moon High latitudes diurnal tides 0 L i 1 l V I 285 I Declination L 3 N E 9 1 o I day I Time gt i t2t39 mry Midlatitudes mixed tides u ge 0 water on side facing the Moon T Stationary 3 bulge of water south 3 g on side facing Poe away from I the Moon 0 I day Time Zgt Low latitudes semidiurnal tides Highest latitudes diurnal tides Low latitudes semidiurnal tides Midlatitudes semidiurnal mixed tides the following are all in theory its not really like that in real life in real life there are continents and a uniform global ocean Equilibrium Tidal Theory Explanation that assumes no continents and a uniform global ocean Theory says you should get diurnal tides at high latitudes semidiurnal at low latitudes and mixed tides in between The problem is that you can t use the previous discussion to accurately predict tides at any one location Dynamic Tidal Theory I Continents disrupt the moonfollowing wave around the globe I Because the tidal wave is contained within individual ocean basins it can oscillate back and forth as a standing wave I The long wavelength of the tide means that it behaves as a shallow water wave hence its speed is controlled by water depth and its arrival can be affected by the slope of the continental shelf etc Motion through gaps between continents and around capes leads to diffraction Moving tidal wave is affected by Coriolis Progressive standing and rotary standing waves I When the wave traverses the ocean like a shallowwater wave it is termed a progressive tide I If a basin is such that the wavelength is twice the length of the basin a standing wave is formed I Coriolis then produces a clockwise spiral termed a rotary standing wave I Node amphidromic point may be associated with bottom features I Tidal behavior at any given onshore location depends very much on the local geometry The tide is funneled into an increasingly narrow space with no place to go highest tide is in Bay of Fundy Tidal Bores When the confining mouth of a river forces the incoming tide wave to move faster than the theoretical shallowwater wave speed for that depth you get what is called a tidal bore The forced wave breaks forming a spilling wave front that moves upriver Predicting tides There are roughly 150 different factors that in uence the tides We have dwelt on only a handful Only through observations over a very long period of time has it been possible to create tide tables for individual locations Meteorological phenomena also in uence tides I e g Storm surge can add to the tidal effect Since astronomical data are not sufficient to calculate tides predictions are based on actual tidal measurements in many areas over an extended period For these observations NOAA maintains a network of l75 tide stations that house equipment to take the following measurements every six minutes 0 tide levels 0 wind speed and direction 0 water current speeds and directions air and water temperatures 0 barometric pressure Coastal Growth 50 of the population of the industrialized world lives within 100 km of a coastline This narrow fringe accounts for lt 20 of US land area but over half of the population and housing supply Since WW 11 there has been a general migration from the interior to the coasts of the world especially in the US Many different types of coasts Constructional coast Hawaii and Galapagos Steep coast fjord Sea cliffs and stacks rocky S Australian Coast waves undercut rocks Tectonic uplift and narrow shelf Glacial built coastlines Tropical coral reefs and mangrove coasts Salt marshes and swamps Deltas river ef uent pours into the sea Controls on Coastal Processes I Preexisting topography I Sediment supply I Tectonic in uences I Hydrographic Setting Wave climate Exposure to ocean swells Tides Exposure to tsunamis I Climatic setting Sea Level Wave interaction as waves feel the bottom they build and break carry sediment speed of the wave is determined by shallowness more shallow more slow the wave is refraction 9 waves bend as they come in As shallow water waves approach shore they interact with the shoaling sea oor remember wave speed is related to water depth Refraction Bending of waves because of varying water depths underneath Diffraction Change in direction of waves as they pass through an opening or around a barrier in their path Re ection WAVE DlLCf07l Waves re ect off objects such a way that the angle at which they approach the barrier equals the angle at which they re ect off the barrier Barrier Islands migrate landward by 9 sand washing over island washover sediments are dumped over during storms exacerbated as sea level rises 9 sand gets caught in the inlet tidal deltas 9 sand eroding and depositing on the deepening seaward shelf Tidal delta space between barrier islands movement of water brings sand Coastal erosion if you have permafrost conditions on the coastline it keeps the sediment and coastline intact sea ice is the same sea ice and permafrost are melting and coastlines are vulnerable to erosion not all coastlines behave the same way to rising sea level Mangroves In South Florida mangroves trap and bind sediment and can protect and even build new land Armoring beaches short term protects real estate Beach renourishment bring new sand can degrade the coastal environment when you pump stuff from offshore you put finer sand on it that moves offshore In addition humans can cause erosion by Damming rivers Cutting artificial inlets which disrupt sand ow Constructing groins and other structures which block sand ow Destroying shore vegetation and dunes Using wrong sand for renourishment Marine Resources World economies began a period of unprecedented growth in the decades following World War II The human population on Earth also more than doubled during this time period Though at one time it was thought that the ocean and its resources were almost limitless in fact they are not Marine resources fall into two categories Living and nonliving Nonliving Offshore Oil and Gas Methane Hydrates potentially Alternate Energy Sources Wind and Tidal 0 Sand and Gravel Manganese Nodules Who owns the 0cean s resources Deepwater Horizon April 20 2010 Explosion ll Rig Crew Killed 0 5 million barrels spilled Exxon valdex I Alaska oil ship I Spilled 260000 barrels of oil What are oil and gas Hydrocarbon formation is a thermochemical process that requires 1 a Source of organic material what geologists call a source rock 2 Heat and 3 lots of Time plastic is hydrocarbonpetroleum derivative longer hydrocarbon chain more soliddense liquid The high temperatures required for oil and gas formation come from deep burial Source rock 9 original rock or sediment that has organic matter a lot of it Ex black shale has to have thermal maturation Where does the organic matter come from In the oceans it s mostly sourced from plankton However under normal ocean conditions very little organic matter typically accumulates in the sediments on the sea oor Why the faster you bury organic material the more it will stay in sediment its also a function of how well preserved the organic materials are best in anoxichypoxic conditions no organisms to take it up The absence of a benthic fauna under anoxic conditions is the key to enhanced organic carbon burial and the production of petroleum source rocks the Black sea is the largest body of anoxic water on Earth today has an estuarine circulation there were large scale ocean anoxic events in earth history periods of deep ocean anoxia and widespread deposition of organic rich black shales significant for generation of hydrocarbon source rocks OAE ocean anoxic events cretaceous period is one show up in black shale horizons drill into sediments Epicontinental sea Shelf Lowoxygen Figure 171 6 Earth System History Second Edition 0 1 How do you make the deep ocean go anoxic Increase surface productivity and O2 demand make ocean really productive and drive anoxic layer or Decrease the ventilation of the deep ocean by slowing down the deep circulation 0 water was warmer holds less oxygen Other requirement for petroleum accumulations 0 Source Rock Reservoir need good porosity and permeability Traps andor Seals like salt domes most recent discovery in 2007 off Brazil salt deposits formed the seal Types of offshore platforms Shallow standing Offshore anchored oating platforms Methane Hydrates Clathrates huge energy resource big climate unknown form only under certain conditions of temp and pressure found in shelf or slope environments major source of methane greenhouse gases methane has 40X the heat trapping capacity than CO2 But there is less of it in the atmosphere PETM Paleocene Eocene Thermal Maximum represents largest extinction in deep sea very warm period no ice spike in oxygen isotopes re ects carbon isotopes shift in carbon isotope more carbon in ocean at this time a time of massive introduction of isotopically distinct carbon into the earth system represents an injection of methan in ocean replacing carbon estimated 1500 2500 gigatons of CH4 people think its melting methane hydrates as you put carbon in ocean lowers pH more acidic methane makes pH drop during PETM ACEX expedition and Integrated Ocean Drilling Program IODP hydrates can cause mass slumping along continental margins as hydrates melt hold sediment like permafrost Energy use tides like wind power tides use offshore sand and gravel Ocean Cay Bahamas world s largest single mining operation aragonite carbonate sand Managanese modules could be potential source of minerals expensive and question over who owns it Though evidence for orbital pacing of the recent Ice Ages is clear there has been long standing uncertainty about how these relatively weak insolation signals result in such dramatic climatic changes Another problem is that insolation variations are out of phase between the hemispheres and yet glacialinterglacial changes are synchronous Insulation in Northern Hemisphere is inverse but out of phase with southern When we build big glaciers in Northern Hemisphere Ice Cores Ice Cores currently provide up to 800000 years of information about Air temperature e g hydrogendeuterium ratio Gas composition of the atmosphere preserved in bubbles e g carbon dioxide and methane concentrations 0 Volcanic eruptions from aerosols dust extent of deserts Annual layers characterize the ice as seen in the face of the Quelccaya Ice Cap in Peru and in the ice core to the upper right count layers in ice for years there is a clear correlation btw temp and atmospheric CO2 and methane concentrations in air greenhouse gases during this time the rise and fall of CO2 and CH4 with temperature re ect coupled feedbacks Orbitallydriven insolation changes initiate the warmingcooling and this leads to feedbacks through the greenhouse gases For example warming causes the ocean to give up CO2 which further amplifies the warming Changes in ocean productivity also appear to play a major role In the case of methane warming causes additional release of CH4 from permafrost and from tropical wetlands today the rate at which we are putting CO2 into the atmosphere is much faster was about 30 ppm per thousand years now its 30 ppm in 15 years Current level of CO2 is outside bounds of natural variability for at least the last 800 kyrs 0 Rate of change of CO2 is also unprecedented During the last period of deglaciation CO2 rose in the atmosphere at a maximum rate of 30 ppm per thousand years As a result of human activities CO2 levels in the atmosphere have risen 30 ppm in the last 15 years it is very likely that glacialinterglacial CO2 variations have strongly amplified climate variations How do we explain lower CO2 levels in the glacial atmosphere 0 The answer is generally thought to lie in the ocean The ocean contains roughly 60 times as much CO2 as the atmosphere on glacialinterglacial timescales the atmosphere is slave to ocean chemistry Numerous mechanisms have been proposed but one key player is almost certainly the ocean s Biological Pump Biological pump productivity phytoplankton take in CO2 from water and gaseous CO2 comes into the water from the atmosphere some CO2 carbon is stored in organic carbon that sinks into the deep ocean John Martin s Iron Fertilization Hypothesis 0 originally proposed in 1990 to explain low glacial CO2 levels 0 Fertilize ocean by making it more productive and taking in more CO2 High Nutrient Low Chlorophyll HNLC regions where we have high nutrients on surface by Antarctica Iron in ice cores tell us that it can also determine climate during certain time periods the iron comes from dust when you have an ice age cool air is dried more dust in atmosphere higher wind Fe gets in the water when you have high Fe you have low CO2 inverses CO2 Lquot R3 IIgi39A in a Large C phytopankton 9 T 4 quot e Small xx 7 EA phyto lankton V 200 c g 4 5 2 v PW vi 3 T k gt o 5 MW 3 39 Bacmnm 8 3 e 393 8 L g I gt 3 0 Deep ocean Deep consumers 4quot BEICIQFI8 Sea floor Lower Global average Increases equatorto atmospheric CO2 surface temperature pole temperature T diminishes gradient Higher intensity of More iron moves to E Increases east biological pump ocean via aerosols west wind speeds Recognition that climate can change so rapidly has caused a sweeping reevaluation of processes that drive major changes in the climate system agriculture begins when climate stops changing Rheostat versus Switch models 0 Slow Milankovitch forcing behaves like a rheostat or dimmer switch 0 Abrupt change is like a light switch that ips quickly into a new stable position Technically an abrupt climate change occurs when the climate system is forced to cross some threshold triggering a transition to a new state at a rate determined by the climate system itself and faster than the cause Around the turn of the 20th century the American geologist TC Chamberlin speculated that the Atlantic circulation might change during Ice Ages He noted that quotthe battle between temperature and salinity is a close one no profound change is necessary to turn the balancequot A 3 C 9 O 3 3 UJ Q E C I 3 quot I 2 E g 4 B 39 C 3 i I U I I D I I 0 I I C 1 1 O1 G O Q 39 i E 9 8 U3 39 lt2 C J5 E O 0 L T freshwater inflow to North Atlantic allow salinity to build up the conveyor belt turns back on as salinity decreases the conveyor belt shuts down provides mechanism for rapid warming The Younger Dryas Meltwater connection cold event that punctuates glaciation about 1000 years we see an interval of high O16O18 30 Vibrio species Motile Curved rod with polar agellum Hardy organism Survives in environment Reservoir Marine amp freshwater Viable for years in low temperature salinity Viable but Not culturable Chitin binding protein amp Zooplankton Biofilm formation Killed by high heat acidity dry conditions Seasonality before and after monsoons Explodes in number with high rain input monsoons Facultative pathogen in humans Mechanism for infecting susceptible body tissues damaging host tissue by growing in the gut and are normally present in the environment Easily spread Cholera background Dr John Snow Retrospective Investigation Did an experiment with the wells which he though has the source 2 Water Companies Lambeth Water intake upstream Southwark amp Vauxhall Water intake downstream sewage outfall Mixed distribution Door to door interviews amp Other data sources Water source Cholera casesdeaths first recorded instance of Epidemiology gt gt gt 2 v Strong Trade Winds H 4 dj gt u lt Rainfall Area Moves East 9 H Weak Trade Winds Weak L I I I I I I Tradewinds i H i dino agellate US Middle east coast estuaries Kills fish by consumption first report 1988 in T ilapia aquaculture NCSU Ciguatera fish poisoning subtropical waters Caribbean pacific CFP cigua Spanish Antilles turban snail predominantly in finfish grows with a benthic stage settles on macroalgae gets biomagnified Settles on macroalgae in reef environments Precursors to ciguatoxins consumed by grazing fish Effect biomagnified up the food chain CFP Symptoms analogous to type E botulism scombroid poison orgPO4 poisoning A Symptoms l Gastrointestinal vomiting abdominal pain nausea diarrhea few days Caribbean 2 Neurological numbnesstingling dizziness hotcold perception weeks months years Pacific B Characteristics CTX is toxic to adult humans at pg quantities and fish cannot be purified of CTX Death rare occurs by respiratory shock when fish live viscera are eaten Treatment mannitol infusion 05 10 gkg body weight opens swelling at nodes Reports of z 50000 casesannum but likely underreported l0fold Detritivores on reefs and carnivores can retain CTX for gt 30 months parrotfish jacks barracudas groupers snappers moray eels surgeonfish especially barracuda West Coast HABs PSP ASP Alexandrium catenella Psuedo nitzschia sp PSP Saxitoxin STX from Saxidomus gigcmteus Alaskan butter clam Characteristics In both cyanobacteria Lyngbya and dino agellates 28 analogues Water soluble fats uptake across GI tract Acts to block voltage sensitive Na Channels same site as terodotoxin Symptoms tingling mouth digits GI tract usual suspects and paralysis Several cases from Indian River Lagoon FL due to toxic puffer fish Pyrodinium bahamense Pseud0 m39tzschz39a sp Identified in 1987 as source of ASP from maritime Canada Domoic Acid heatstable water soluble Competes with glutamate for binding site in neurons concentrated in large shell fish
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