Tag Archives: water pollution

Three Simple Facts About Jellyfishes

How long does it take for the jellyfish to stay alive out of sea water? Do jellyfishes melt in the rain? What ecological role do jellyfishes play in the marine ecosystem? These are three questions answered in this article. Read on to find out.

The trip to Kitu-Kito, a tourist destination north of Puerto Princesa, on board a raft made of large PVC tubings, appeared to be uneventful until tiny blobs of jellyfishes of different sizes gained our group’s attention. While a scourge to swimmers, the jellyfishes became a subject of photographic interest for me.

Various sizes of jellyfishes bob out of the water, from 5-inch diameter ones with venomous tentacles to the cute, half-inch juveniles. Here are two of them:

jelly fishes
Two jellyfishes swim about in the food container filled with water.

How Long Can Jellyfishes Stay Out of the Water?

Taken by curiosity and instinctively, our boatman caught one of the jellyfishes and placed it on the front edge of the raft. The transparent jellyfish helplessly throbbed just like a heart on the wooden surface indicating that it is alive. Its gelatinous bell (its head) looks edible.

The taste of nata de coco flashed in my mind. I had that urge to slice and eat the chewy head.

I wonder if it tastes like nata de coco? Are jellyfishes edible? The boatman said, “Yes, it is.”

The jellyfish, in fact, is a delectable delicacy in Asia. These are dried, preserved and shipped to restaurants in Japan, China, and Thailand. But I never had the chance to taste it and will not venture to do so unless everybody is eating it.

jellyfish with tentacles
The jellyfish looks like nata de coco, a chewy, translucent, jelly like foodstuff produced by the fermentation of coconut water.

“How long can jellyfishes survive out of the water?” asked one of my friends. Being a biologist, and, not knowing exactly how long it will take for these animals to stay out of the water, I retorted, “Let’s use a timer to find out.” And so we did.

Glancing once in a while and observing the jellyfish for its tell-tale throb of life somewhere in the middle of its body, we waited until no discernible movement to indicate life is evident. After a while and looking at my watch’s timer, I blurted out to the group: “48 minutes.”

Now we learned that jellyfishes could survive that long out of sea water. If it does not return within that period to the deeper parts of the sea during the rush of sea water towards low tide levels, then it gets isolated and fried under the sun or get dehydrated. Thus, it somehow distributes nutrients along the coastline as it becomes a part of the beach ecosystem food chain.

Do Jellyfishes Melt in the Rain?

Another question sprang up. “Is it true that jellyfishes melt when out of the water and exposed to the rain?”

Honestly, I could not think of a good reason why jellyfishes will melt in the rain. They’re not ice cream or made of ice. I have heard this wrong notion on many occasions. And so I simply said, “I don’t think so,” explaining a bit about the composition of animal tissue.

As if to confirm my point, by sheer coincidence, it rained that afternoon despite the generally fair weather in the morning. The raft shook with every gust of wind that pass our way and alarmed almost everyone. I have been through this situation many times in the field and I feel confident that the wind will settle in a few moments.

The raindrops fell on the jellyfish, washing it through and through. The jellyfish, of course, did not melt. It’s still there.

3. Ecological Value of Jellyfishes

Jellyfishes form part of the marine food chain. They prey mainly on the zooplankton. In turn, they are favorite diets of sea turtles. Thus, they help stabilize the marine ecosystem.

Transparent plastics thrown into sea water sometimes get mistaken for jellyfishes. This is the reason many sea turtles die as plastics block their gut and keep them full when, in reality, they are without food in their stomachs.

© 2014 September 8 P. A. Regoniel

Water Pollution: Sources, Transport and Distribution of Heavy Metals

Heavy metals are considered as persistent water pollutants. Where do heavy metals come from, and how are these toxic substances transported and distributed? This article reviews several literature along these concerns.

The introduction of substantial chemical, physical or biological material into the coastal zone from land-based sources due to industrialization as well as natural processes such as land erosion affects the organisms living in it. This is so considering that the process involves discharge of insidious and persistent toxic pollutants such as pesticides, heavy metals and other nondegradable and bioaccumulative chemical compounds.

The potential hazard to the marine environment of pollutants depends mostly on their concentration and persistence. Persistent pollutants, such as heavy metals, can remain in the environment unchanged for years (Guzman and Jimenez, 1992). These heavy metals eventually find their way into the tissues of marine organisms as a result of ingestion.

Continuous uptake of heavy metals would lead to an increased concentration in the organisms’ tissues (bioaccumulation) until a saturation point is reached where these metals would interfere with an organism’s vital functions.

Sources of Heavy Metals

In particular, the kinds of heavy metals incorporated in sewage outputs to the aquatic ecosystem vary widely. These are determined principally by the nature of pollution sources whence these metals came.

Possible pollution sources identified by Guzman and Jimenez (1992) include:

1. point sources such as refineries, power plants, ports, dockyards, domestic and industrial sewage;

2. non-point sources such as domestic and industrial sewage, agriculture activities, soil erosion; and

3. unpredictable point sources (e. g. oil waste at sea by tankers, major oil spills.

Discharges of oil at sea by tankers, the use of antifouling and anticorrosive paints to protect vessels and structures, oil spills during shipping and terminal transfers and effluent discharges from refineries are probably among the anthropogenic sources of lead (Pb), chromium (Cr), iron (Fe), copper (Cu), zince (Zn), cadmium (Cd), and vanadium (V) (Guzman and Jimenez, 1992). Also, all metals are normal components of fertilizers, lime and pesticides (Davies, 1980; Alloway, 1990).

Transport and Distribution of Heavy Metals

Owing to the metal’s soluble and particulate nature, heavy metal pollution transcends boundaries. This suggests that a wide range of pollution sources, both natural and anthropogenic, and a very effective mechanism for disturbing metals influence heavy metal transport and distribution (Guzman and Jimenez, 1992).

Rivers appear to be the most important sources of heavy metals in the sea and they carry much larger quantities of the elements as particulates than they do as solutes (Bryan, 1976). These heavy metals which may initially be deposited in one section of a coast or bay tend to be distributed to other regions because of tidal cycles, mixing of water layers and upwelling (Eslemont, 1999), currents, and occasional strong forces in nature such as typhoons, among others. Natural processes prevailing in particular locations influence the concentration of heavy metals.

In Darwin Harbour for example, Eslemont (1999) noted that the strong tidal cycle tends to disperse pollutants. Because of these processes, even the pristine coral reefs are influenced by metal pollution, although at lower levels than the other reefs proximate to pollution sources.

However, the influence of benthic infauna especially on sediment structure, chemistry and transport could not be underestimated. The disturbance of sedimentary deposits by living organisms (bioturbation) could influence sedimentary structure and therefore has important implications for the fate of contaminants. Mazik and Elliot (2000) have demonstrated that there was an increase in bioturbation with increasing distance from the source of pollution.

Literature Cited

Alloway, B. J., 1990. Heavy Metals in Soils. Blackie, London (in Guzman and Jimenez, 1992).

Bryan, G. W. (1976). Heavy metal contamination in the sea. In Marine Pollution (R. Johnston, ed.), pp. 185-302. Academic Press, London (in Guzman and Jimenez, 1992).

Davies, B. E., 1980. Applied Soil Trace Elements. John Wiley & Sons, New York (in Guzman and Jimenez, 1992).

Eslemont, G., 1999. Heavy metals in corals from Heron Island and Darwin Harbour, Australia. Marine Pollution Bulletin, Vol. 38, No. 11, pp. 1051-1054.

Guzman, H. M. and C. E. Jimenez, 1992. Contamination of Coral Reefs by Heavy Metals along the Caribbean Coast of Central America (Costa Rica and Panama). Marine Pollution Bulletin, Vol. 24, No. 11, pp. 554-561.

Mazik, K. and M. Elliott, 2000. The effects of chemical pollution on the bioturbation potential of estuarine intertidal mudflats. Helgoland Marine Research, Vol. 54, Issue 2/3 pp. 99-109.

© 2014 June 12 P. A. Regoniel