¿Puede la contaminación orgánica afectar la tasa de crecimiento de los octocorales en el Caribe?

Organic pollution in the Havana coastline is affecting octocorals assemblages, and little is known about its effect on the growth rate (GR). A fi xed belt transect (250 x 2 m) was used to locate the colonies. The GR of Eunicea fl exuosa and Plexaura kuekenthali was signifi cantly higher in the reef with more organic pollution (3,6 cm/año y 4,1 cm/año, respectively) vs. reference sites, which seems to be related to their heterotrophy.La contaminación orgánica en el litoral de La Habana está afectando las asociaciones de octocorales, y poco se conoce su efecto en la tasa de crecimiento (TC). Se empleó un transecto de banda fi jo (250 x 2 m) para localizar las colonias. La TC de Eunicea fl exuosa y Plexaura kuekenthali fue signifi cativamente mayor en el arrecife con más contaminación orgánica (3,6 cm/año y 4,1 cm/año, respectivamente) vs. sitios de referencia, lo que parece estar relacionado con su heterotrofía

Resiliencia en crestas de arrecifes coralinos del este del golfo de Batabanó, Cuba, y factores determinantes probables

RESUMEN Se comparó el grado de resiliencia de seis crestas arrecifales del este del golfo de Batabanó, Cuba. Tres fueron del norte del golfo de Cazones (Tramo Norte) y las restantes, del oeste de Cayo Largo (Tramo Sur). Las del primer tramo fueron las de faro Cazones, Norte de la cresta de cayo Diego Pérez y de faro Diego Pérez. Las otras tres fueron las de cayo Rico, arrecifes Los Ballenatos y arrecifes Hijos de Los Ballenatos. Se emplearon los indicadores biológicos del Protocolo AGRRA. El Tramo Norte presentó las crestas más resilientes, sobre todo la de faro Cazones. Las del Tramo Sur no exhibieron resiliencia. Fueron varios e interrelacionados, los factores aparentemente más determinantes en la resiliencia. Entre estos, cuatro se consideraron como fuerzas motrices: resguardo contra el oleaje, circulación habitual giratoria ciclónica en la ensenada de Cazones, entrada de nutrientes provenientes tanto de la ciénaga de Zapata como de aguas profundas, y abundancia del erizo herbívoro Diadema antillarum. Los demás factores, desencadenados por los anteriores y también interrelacionados, fueron, al parecer la menor afectación por oleaje y sedimentos, estabilización de fragmentos vivos de coral, índices favorables de macroalgas bentónicas, cierta retención de nutrientes y plancton, más alimentación heterotrófica de los corales, mayor auto reclutamiento de corales y del erizo Diadema; mejores condiciones para el asentamiento y viabilidad de los reclutas, y para el recapamiento de corales; mayor crecimiento y recuperación de los corales y mejores condiciones térmicas contra el blanqueamiento de corales ABSTRACT The degree of resilience of six reef crest sites was compared at the east of the Gulf of Batabano, Cuba. Three of them were located north of the Gulf of Cazones (Northern Stretch), while the remaining ones were west of Cayo Largo (Southern Stretch). Those of the Northern Stretch were “Faro Cazones”, north of the crest of cayo Diego Pérez and “Faro Diego Pérez”. The remaining sites were those of the cayo Rico, Los Ballenatos reefs, and Hijos de Los Ballenatos reefs. The AGRRA biological indicators were applied. The Northern Stretch presented the most resilient crests, mainly that of “Faro Cazones”. Those of the Southern Stretch did not reveal signs of resilience. Several interrelated factors were apparently more linked to resilience. Four of them were considered as driving forces: shelter from waves, usual cyclonic revolving water circulation in the Ensenada de Cazones, nutrient input from the Zapata swamp and deep water, and the abundance of the herbivore sea urchin Diadema antillarum. Triggered by these driving forces, the remaining factors apparently were less effect of waves and sediments, stabilization of live coral fragments, favorable benthic macro-algae indices, some retention of nutrient and plankton, increased coral heterotrophic feeding; better conditions for recruit settlement and viability, and for coral re-sheeting; faster coral growth and recuperation and better thermal conditions against coral bleaching

Mean growth rate (cm/year) in height (95% CI) of <i>E</i>. <i>flexuosa</i> and <i>P</i>. <i>kükenthali</i> at sites influenced by discharges from polluted river basins and sites not impacted by those basins.

Mean growth rate (cm/year) in height (95% CI) of E. flexuosa and P. kükenthali at sites influenced by discharges from polluted river basins and sites not impacted by those basins.</p

Pearson´s correlation between the morphometric indicators of <i>P</i>. <i>kükenthali</i> and the microbiological, hydrochemical, and physical variables and stable nitrogen isotopes of <i>P</i>. <i>kükenthali</i>.

FC: fecal coliform bacteria, HB: heterotrophic bacteria, TC: total coliform bacteria, SR: sulfate-reducing bacteria, FE: fecal streptococcal bacteria, DIN: dissolved inorganic nitrogen, and HSI: hydrodynamic stress index. The correlations in black indicate P values (PDF)</p

Fig 8 -

Linear regression between the density and height of E. flexuosa (top) and P. kükenthali (bottom) in the sampling years. The dotted lines represent the upper and lower 95% confidence intervals.</p

Pearson´s correlation between the morphometric indicators of <i>E</i>. <i>flexuosa</i> and the microbiological, hydrochemical, and physical variables and stable nitrogen isotopes of <i>E</i>. <i>flexuosa</i>.

FC: fecal coliform bacteria, HB: heterotrophic bacteria, TC: total coliform bacteria, SR: sulfate-reducing bacteria, FE: fecal streptococcal bacteria, DIN: dissolved inorganic nitrogen, and HSI: hydrodynamic stress index. The correlations in black indicate P values (PDF)</p

Relative size-frequency (based on height) distributions of <i>E</i>. <i>flexuosa</i> along the water quality gradient over the 2008–2016 period.

The percentage of recruits is shown in the ≤ 10 cm size interval (orange numbers). The results of pairwise comparisons of the PERMDISP test are shown (lowercase letters in brackets). N: sampling size. Sampling sites codes are presented in Fig 1.</p

Map of the sampling sites in an area of northwest Cuba.

Principal coordinates analysis (PCO) plot shows the water quality gradient according to the microbiological, hydrochemical and physical variables and stable nitrogen isotopes of two octocorals. The vectors indicate the strongest Spearman’s correlation (r > 0.7) between the variables and the PCO1 and PCO2 axes. The number in parentheses is the location of each site along PCO1. Sa: Playa Salado, CH: Club Habana, IO: Institute of Oceanology, DS: underwater sewage outfall of 180 Street, C30: 30 Street, Pu: La Puntilla, PAM: Parque Antonio Maceo and Ca: Boca de Calderas. FC: fecal coliform bacteria, TC: total coliform bacteria, FE: fecal streptococcal bacteria, HB: heterotrophic bacteria, NH4+: ammonium, NO3- + NO2-: nitrate + nitrite, DIN: dissolved inorganic nitrogen, Vis: water visibility (m), Sed: bottom-sediment accumulation, Efle: E. flexuosa, Pkük: P. kükenthali.</p

Relative size-frequency (based on height) distributions of <i>P</i>. <i>kükenthali</i> along the water quality gradient over the 2008–2016 period.

The percentage of recruits is shown in the ≤ 10 cm size interval (orange numbers). The results of pairwise comparisons of the PERMDISP test are shown (lowercase letters in brackets). N: sampling size. Sampling sites codes are presented in Fig 1.</p