Principles of marine degradation 1

contents and introduction

by Dr J Floor Anthoni (2004)
www.seafriends.org.nz/issues/cons/degrade.htm
Environmental degradation has become the most serious threat to the health of our seas, particularly to our coastal seas. But because it is so difficult to see, while progressing only slowly, most people and scientists have remained obtuse (= blind to the obvious). For instance, practically no scientific research has been done anywhere in the world, into how degradation works or how it can be measured. This large chapter therefore attempts to put my personal thoughts and observations into a coherent framework that may perhaps become the beginning of a new and eventually large discipline of science. Please note that this whole chapter covers entirely my own findings and speculations, since no references can be found in either the scientific literature or textbooks. If you are neither a diver nor a scientist, you may still find this chapter fascinating, because in the end, degradation will affect your life and even more so that of your children. Although the principles outlined here are universally applicable, I have from necessity, restricted myself to examples from New Zealand seas. This chapter will grow as new insight is gained.
The naturalist's achievement is first and foremost a personal one, a state of mind representing a profound understanding of and with the natural world. It cannot be shared like the predictive power of a scientific theory. Nevertheless this understanding is among the precious and extraordinary qualities which justify human existence. - R H Peters (1992)

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this long chapter consists of 4 parts: part1(contents), part2, part3, part4 according to their colours

introduction An introduction to the problem and its origins.
 degradation principles Although little is known of degradation, nonetheless certain principles can be formulated to help understand it.
cycles and trends
How do cycles and trends work? Are they natural or unnatural?
DMS cycle Could the increase in rainfall have been produced by the plankton? Are we entering a disastrous vicious cycle?
resilience Some organisms are sensitive whereas others are more robust. Why?
 indicators of doom A long list of indicators showing what to look for.
indicator species Do indicator species have things in common? Which organisms are good indicators of which threats?
 the cleaning gang Many organisms have beneficial effects on their surroundings, mitigating or postponing the ill effects of degradation. When they die, their environment may go through a critical period.
unhappiness Many organisms display a kind of unhappiness or ill health before dying. These are important warnings as they are visible on organisms which have not yet disappeared and which may recover without surrendering their space.
 timeline
As degradation intensifies, it manifests itself in more and more symptoms. The timeline chronicles degradation events and when symptoms were first seen. The timeline has been placed in a separate document because it is updated regularly and relates only to the situation in New Zealand. Only reading is believing! (4 pages)
examples This chapter has restricted itself to the principles of degradation without giving many examples. Follow the documents below to familiarise yourself with the various visual aspects of degradation. This section will grow as more images become available. For now, just imagine the outcry of indignation had these images come from our National Parks!
decay: many photographic examples in several chapters, richly annotated (large)
related pages
on this web site
Read the important chapters below to gain a more thorough understanding
Soil: a large section on the origins, functioning, sustainability and loss of soil. Very important.(large)
Resource management: understanding stressors and resilience and much more. (28p)
Biodiversity: understanding the variety of life and how the sea differs from the land. (32p)
Introduction to habitats: understanding what it means to live in the sea. (14p)
Principles of conservation: understanding threats and their remedies and why many won't work. (30p)
Marine conservation: principles of marine conservation and differences between land and sea. (34p)
The intertidal rocky shore: principles and factors, illustrated by many examples and species. (80p)
The plankton balance hypothesis: how plankton feeds and kills, and what this means. Very important to understand degradation. (10p)
The Dark Decay Assay: a new method to measure the activity of planktonic decomposers, enabling amateurs to measure degradation in lakes, rivers and the sea. Read how the most important ecological laws of this planet were discovered using the DDA. The sea does not work as previously thought! Only reading is believing!
Internet links scirus Elsevier's impressive science search engine to find science done on degradation. Try if you can find any, preferably before publication of this chapter (2004).
For comments, corrections or suggestions, please e-mail the author Dr Floor Anthoni.
Note! for best printed results, set your page up with a left margin of 1.5cm (0.3") and right margin of 1.0cm (0.2"). Read printing instructions.
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Introduction
Degradation of the sea is not new, since it has been with us for as long as Man changed his environment. But in recent times it has been accelerating because of the multiplying effect of increases in populations, wealth and wastes. To feed more people better, we need more arable land and more water for irrigation. Although agricultural engineering has produced better crops, these also need more fertiliser and pesticides. At the dawn of genetic engineering (GE), we can only guess at the benefits expected of it. But for now we must assume that for many years to come, it will be 'business as usual' and the many problems negating previous progress appear to be accelerating.

But there are also compounding effects. As more and more forests were converted to arable lands, it changed the world's weather and climates quite profoundly, resulting in even more problems. Everywhere in the world the weather now oscillates between larger extremes of heat, drought, flooding and so on. Such fluctuations do not help sustainability, reason why the soils of our Earth are washing into the seas at an ever increasing rate.

Most of the heat transferred from equator to poles and from sea to the continents happens by winds laden with moisture. Because of the enormous amounts of energy locked up and released by evaporation, condensation and rainfall, air circulation takes care of over 60% of all heat transport on Earth. The remaining part is done by ocean currents. Because of the short-circuit in the water cycle (due to deforestation), less moisture reaches the centres of continents and less heat is dispersed this way, resulting in extremes in temperatures and drought. At the same time, winds increase their intensity (due to higher temperature differences), travelling mainly along continental margins where rains become heavier. These combined changes in weather all over the world bring with them large increases in erosion. In NZ the problem has been exacerbated by the sudden abolishment of subsidies on fertiliser in 1986.

The stable soils of the world that have been cultivated for a long time (many centuries) are not causing undue problems, but as good land became scarce, more marginal lands were opened up in places that were either too steep, too wet, too dry, too hot or too cold. After 50 years (typically) such lands become 'tired' and turn into wastelands with little cover, ready to be washed away into the sea. New Zealand is a classic example of this. Only recently have estimates been made of the soil loss in our country, amounting to over 270 million tonnes per year. But my own observations have shown the amount of soil loss almost to be doubling each decade since the subsidy on fertiliser was abolished in 1986. It was the reason for establishing Seafriends and writing this web site while researching 'Why are we losing so much so fast?'. Please read the soil section to quickly inform yourself.
 
 
 

Soil statistics for New Zealand
The following statistics aim to illustrate the problem with soil loss in New Zealand. Total land area: 27,050,000ha. Soil loss estimated at 270 million tonnes per year or 10t/ha which is about 5-10 times the sustainable rate of 1-2 t/ha. 
New Zealand loses between 200 and 300 million tonnes of soil to the oceans every year. This rate is about 10 times faster than the rest of the world, and accounts for between 1.1 and 1.7 percent of the world's total soil loss to the oceans, despite a land area of only 0.1 percent of the world's total. [1]

The use of Synthetic fertiliser consumption is up 21% during 1996 to 2002. The Nitrogen fertiliser urea consumption is up 160% during 1996 to 2002. [2]
Land under irrigation is increasing at a rate of around 55% nationally each decade [3]

Most rivers in farming areas, particularly in lowlands, generally fail to meet recommended guidelines as a result of contamination from increased nutrients, turbidity and animal faecal matter. [1]

New Zealand soils were formed under very slow metabolising forests, resulting in deep B and C horizons (subsoils). Correspondingly, natural erosion was very low, and rivers, lakes and seas clear. NZ aquatic and marine organisms have evolved in clear waters, reason that they are affected so much today. [4]

[1] Parliamentary Commissioner for the Environment paper “Growing for good – Intensive farming, sustainability and New Zealand’s environment” released in October 2004 and downloadable from www.pce.govt.nz
[2] Statistics NZ 1996 – 2003a
[3] Lincoln Environmental 2000c. Lincoln Agricultural University
[4] Floor Anthoni.


 
deep soils in New ZealandDeep soils in New Zealand
New Zealand has a number of problems arising from its unique situation. Over 60 million years of isolation has given it the non-deciduous Podocarp forests that grow slowly while producing persistent leaf litter which decomposes only slowly. Its mild sea climate produces rain in all seasons, such that soils developed in a continuum of available moisture. As a result, deep subsoils developed underneath the native forests and because of this depth, these subsoils also formed slowly above the underlying bedrock. Natural erosion was unusually low and the marine organisms of NZ evolved in these conditions of clear seas.
After deforestation, the top soils provided a rich matrix for grasslands but these top soils eventually thinned, depending on slope and available moisture. As the top soils thinned, the natural fertility was lost and fertilisation became more than necessary. Eventually the subsoil became bare, allowing rain drops to impact directly on the subsoil loams. From here on erosion accelerated rapidly with consequent problems in the sea. Then in 1986 the subsidy on fertiliser was abolished, resulting in underfertilisation of hill country, and a rapid increase in soil loss.
Another important factor is the environment's ability to absorb moisture. Native forests retained water on leaves, bark and the very porous top soil. The temperate loams are also able to absorb moisture inside the layered crystal structure of clay. Once forests became pastures, the ability of the environment to store moisture diminished considerably, resulting in increased run-off with associated gully and river erosion. Now the soils are exposed to repetitive cycles of wetting and drying, which is detrimental to soil fertility while also accelerating soil loss.

 
Chronic decline of fish at the Poor KnightsIs it really serious?
It is human nature to remain obtuse (=blind to the obvious) until bad times knock on one's own door. The calls of visionaries and those who have a keen sense of perception remain unheeded as also newspapers do not wish to bring bad news for their advertising revenues. We also have grown used to our problems going away due to the concerted efforts of scientists and the application of new technology. Why should we be worried?
The fact that none of our existing mainland marine reserves are working, as they are all degrading, is carefully hushed up and funding is not made available for studying the new threat from degradation. The diagram shown here was compiled from information in a scientific study done for the Department of Conservation (DSIS142), which cost the tax payer over NZ$280,000. It was done to show that marine reserves are working because snappers (Chrysophrys auratus) return after a complete ban on fishing in the Poor Knights Islands, located about 20km out in sea, in late 1998 (after the first sample on the diagram). 
This diagram shows the abundance of the fish that normally belong to the Poor Knights and breed there. These are not seasonal stragglers or migratory fish. Scientists counted the number of fish in a 125 square metre transect, which equals roughly the size of a tennis court. Notice the use of three different scales, but the picture is undeniable: fish are disappearing. This is what we have been seeing for over fifteen years as also the water quality deteriorated. Remember that this is the best of our coastal marine reserves, so it takes little imagination how all the others fare. Yet the scientists who collected and published this information, did not notice it and mentioned not one word about it in their report! Note how sweep (Scorpis lineolatus) are increasing their numbers, as these really belong to near-coastal waters, demonstrating that the water quality at the Poor Knights is deteriorating alarmingly. So, should we be alarmed if even our best marine reserve located on the edge of the continental shelf, is helplessly degrading?
 
 
In a recent study, marine scientists quantified coastal marine communities in 13 marine reserves spanning the length of New Zealand. They looked at algal communities and their grazers, particularly the green sea urchin Evechinus chloroticus. They also noted environmental variables such as slope of the substrate (rock) and made an estimate of the fetch (distance over open water) as a measure of wave exposure. To their credit, they also included degradation variables of Secchi disc visibility (the opposite of turbidity) and the percentage sediment cover. They also included the maximum transect depth even though they did not dive deeper than 12m. Their most important result is the proof that degradation (=turbidity + sediment) is by far the most decisive factor on what grows where. In other words, the seascape cannot be understood without understanding degradation
Effects of environment variables
25  turbidity/ visibility
18  sediment cover
10  maximum depth of transect
  7  slope, aspect
  6  fetch, wave exposure
  4  sea urchins in the open
  0.5  marine reserve or not
Yet it took us over 15 years of prodding to get them interested in this very important phenomenon! Note how the presence of sea urchins also plays a role (of course) but that marine reserves have practically no effect at all, proof that they do not save the environment against degradation. Why did the report not mention these points?

Shears NT, Babcock R C (2004): Indirect effects of marine reserve protection on New Zealand's rocky coastal marine communities. DOC Science Internal Series DSIS192 (free on DOC's web site www.doc.govt.nz)
 
 

Eutrophication symptoms reported by mainstream science
  • disturbance of a 'balance' within the plankton, refected in the Redfeld Ratio of N:P:Si=16:1:1.
  • non-siliceous plankton species (dinoflagellates etc.) dominate vs siliceous ones (diatoms, flagellates).
  • increased plankton primary production (phytoplankton) compared to benthic (bottom) primary production.
  • increase in phytoplankton but a decrease in zooplankton.
  • growth of micro algae and nuisance species and opportunistic species, particularly in fresh water.
  • harmful algal blooms (HABs) of non-siliceous species (dinoflagellates etc.).
  • microbial foodwebs (bacteria) dominate compared to linear food chain (zooplankton to fish).
  • reduction in species and biomass.
  • gelatinous zooplankton (jellies) dominates vs crustacean zooplankton (krill etc.).
  • suspension feeders (seasquirts, sponges) and burrowing detritus feeders (worms, etc) dominate
  • oxygen depletion and H2S (hydrogensulphide) formation.
  • death.

Note that all the above observations are supported and further explained by our discovery of the Plankton Balance and further discoveries with the Dark Decay Assay (DDA).

In this section we'll discuss the principles behind marine degradation and how it manifests itself, in order to better understand what is going on in the sea.


go to part2 <=> go to part3 <=> go to part4
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